Publications
This is the shared publication archive for all three research groups in the SLAM cluster, including work from its earlier history as a single group. The list is not fully up to date.
As an additional resource, publications from the Structured Photons group can also be found on Google Scholar.
Notice: when links to PDF files are available, these files are usually copyrighted and may be downloaded for personal use only; any other use requires prior permission of the author and/or the publisher. For open access papers only the link to the publisher page is provided, as the file can be downloaded there. For other papers, you can contact the authors to ask for a reprint.
2026
Fazilah Nothlawala; Bereneice Sephton; Pedro Ornelas; Mwezi Koni; Bruno Piccirillo; Liang Feng; Isaac Nape; Vincenzo D’Ambrosio; Andrew Forbes
Remote engineering of particle-like topologies to visualise entanglement dynamics Journal Article
In: LIGHT, SCIENCE & APPLICATIONS, vol. 15, no. 1, pp. 368, 2026, ISSN: 2047-7538.
@article{nothlawala_remote_2026,
title = {Remote engineering of particle-like topologies to visualise entanglement dynamics},
author = {Fazilah Nothlawala and Bereneice Sephton and Pedro Ornelas and Mwezi Koni and Bruno Piccirillo and Liang Feng and Isaac Nape and Vincenzo D’Ambrosio and Andrew Forbes},
url = {https://doi.org/10.1038/s41377-026-02443-x},
doi = {10.1038/s41377-026-02443-x},
issn = {2047-7538},
year = {2026},
date = {2026-09-01},
urldate = {2026-09-01},
journal = {LIGHT, SCIENCE & APPLICATIONS},
volume = {15},
number = {1},
pages = {368},
abstract = {Skyrmions are a particle-like topology with a quantized skyrmion number, realized across condensed matter and photonic platforms alike. In quantum photonics, they constitute an emerging resource, promising robust quantum information encoding, so far realized as single-photon and bi-photon entangled states. Here we report the first visualization of tripartite entanglement dynamics through topological structure using spin-skyrmion entangled states, where the topology of a single photon is remotely controlled through the spin of its entangled partner. We visualize our tripartite state theoretically by introducing the notion of a topological Bloch sphere that completely captures the entanglement and topological features of the state. By leveraging this state, we realize the first quantum multiskyrmions, comprising multiple localized skyrmions within a single structure, that emulate signatures of their magnetic counterparts. We verify this experimentally and show that traversing our topological sphere reveals entanglement-driven particle-like motion of the localized topological structures. These dynamics unveil a physical manifestation of tripartite entanglement correlations which we illustrate by example of GHZ-like states, enabling a visualization of multiple Bell states encoded within our system. Our work opens exciting possibilities for quantum sensing by mapping complex quantum channel features onto topological observables of multipartite states and offers a promising avenue for harnessing quantum topologies for multi-level encoding quantum communication schemes.},
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Skyrmions are a particle-like topology with a quantized skyrmion number, realized across condensed matter and photonic platforms alike. In quantum photonics, they constitute an emerging resource, promising robust quantum information encoding, so far realized as single-photon and bi-photon entangled states. Here we report the first visualization of tripartite entanglement dynamics through topological structure using spin-skyrmion entangled states, where the topology of a single photon is remotely controlled through the spin of its entangled partner. We visualize our tripartite state theoretically by introducing the notion of a topological Bloch sphere that completely captures the entanglement and topological features of the state. By leveraging this state, we realize the first quantum multiskyrmions, comprising multiple localized skyrmions within a single structure, that emulate signatures of their magnetic counterparts. We verify this experimentally and show that traversing our topological sphere reveals entanglement-driven particle-like motion of the localized topological structures. These dynamics unveil a physical manifestation of tripartite entanglement correlations which we illustrate by example of GHZ-like states, enabling a visualization of multiple Bell states encoded within our system. Our work opens exciting possibilities for quantum sensing by mapping complex quantum channel features onto topological observables of multipartite states and offers a promising avenue for harnessing quantum topologies for multi-level encoding quantum communication schemes.
Maria Gorizia Ammendola; Italo Machuca Flores; Sneha Dey; Francesco Di Colandrea; Andrei Nomerotski; Bereneice Sephton; Carlo Schiano; Corrado Lisio; Vincenzo D’Ambrosio; Lorenzo Marrucci; Patrick Cameron; Filippo Cardano
Tunable quantum interference in free space with a liquid-crystal metagrating Journal Article
In: OPTICA QUANTUM, vol. 4, no. 4, pp. 374–381, 2026.
@article{ammendola_tunable_2026,
title = {Tunable quantum interference in free space with a liquid-crystal metagrating},
author = {Maria Gorizia Ammendola and Italo Machuca Flores and Sneha Dey and Francesco Di Colandrea and Andrei Nomerotski and Bereneice Sephton and Carlo Schiano and Corrado Lisio and Vincenzo D’Ambrosio and Lorenzo Marrucci and Patrick Cameron and Filippo Cardano},
url = {https://doi.org/10.1364/opticaq.597375},
doi = {10.1364/opticaq.597375},
year = {2026},
date = {2026-08-01},
urldate = {2026-08-01},
journal = {OPTICA QUANTUM},
volume = {4},
number = {4},
pages = {374–381},
abstract = {Structured optical materials provide a promising platform for photonic quantum information processing in free space. Beam splitters, a fundamental building block of photonic circuits, have recently been demonstrated in free space using geometric-phase optical elements. These devices coherently mix circularly polarized transverse modes of freely propagating optical fields, including modes carrying orbital angular momentum. In this work, we investigate liquid-crystal metagratings as electrically tunable beam splitters for transverse-momentum optical modes. By exploiting the voltage-controlled birefringence of liquid-crystal metasurfaces, we experimentally tune the splitting ratio of the device and thereby control the degree of two-photon interference between indistinguishable photons. At the output, photons are spatially resolved in different regions of a time-resolved single-photon-sensitive detector, enabling the reconstruction of coincidence maps in the Fourier plane. This approach is readily scalable and enables highly parallel coincidence measurements across a large number of optical modes.},
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Structured optical materials provide a promising platform for photonic quantum information processing in free space. Beam splitters, a fundamental building block of photonic circuits, have recently been demonstrated in free space using geometric-phase optical elements. These devices coherently mix circularly polarized transverse modes of freely propagating optical fields, including modes carrying orbital angular momentum. In this work, we investigate liquid-crystal metagratings as electrically tunable beam splitters for transverse-momentum optical modes. By exploiting the voltage-controlled birefringence of liquid-crystal metasurfaces, we experimentally tune the splitting ratio of the device and thereby control the degree of two-photon interference between indistinguishable photons. At the output, photons are spatially resolved in different regions of a time-resolved single-photon-sensitive detector, enabling the reconstruction of coincidence maps in the Fourier plane. This approach is readily scalable and enables highly parallel coincidence measurements across a large number of optical modes.
Patrick Cameron; Francesco Di Colandrea; Filippo Cardano; Lorenzo Marrucci
Evidence for Counterfactual Violation of Local Conservation Laws in Quantum Events Working paper
2026, (arXiv:2608.09205 [quant-ph]).
@workingpaper{cameron_evidence_2026,
title = {Evidence for Counterfactual Violation of Local Conservation Laws in Quantum Events},
author = {Patrick Cameron and Francesco Di Colandrea and Filippo Cardano and Lorenzo Marrucci},
url = {http://arxiv.org/abs/2608.09205},
doi = {10.48550/arXiv.2608.09205},
year = {2026},
date = {2026-08-01},
urldate = {2026-08-01},
publisher = {arXiv},
abstract = {Physical conservation laws, such as those of energy and momentum, are generally believed to hold exactly and locally in spacetime, including in quantum phenomena. Yet Aharonov, Popescu, and Rohrlich (APR) recently argued, on the basis of a thought experiment, that individual quantum events, unlike ensemble averages, may occasionally violate local conservation laws. Their argument relies on the wave phenomenon known as "superoscillations", which APR themselves discovered more than 30 years ago. Here we provide experimental evidence for such a violation. We extract photons from a small superoscillatory region near the core of an optical vortex and show that their mean transverse momentum is statistically incompatible with a general bound implied by local momentum conservation. The derivation of this bound requires only the theoretically well-supported assumption that the extraction mechanism does not alter the photons' mean transverse momentum. We also detect photons with high transverse momentum at a rate significantly exceeding that predicted by a model assuming local momentum conservation. Because this violation can be established only counterfactually and through postselection, it does not conflict with relativistic causality. Our results may represent the first example of a distinct form of quantum nonlocality that does not explicitly rely on entanglement.},
note = {arXiv:2608.09205 [quant-ph]},
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Physical conservation laws, such as those of energy and momentum, are generally believed to hold exactly and locally in spacetime, including in quantum phenomena. Yet Aharonov, Popescu, and Rohrlich (APR) recently argued, on the basis of a thought experiment, that individual quantum events, unlike ensemble averages, may occasionally violate local conservation laws. Their argument relies on the wave phenomenon known as "superoscillations", which APR themselves discovered more than 30 years ago. Here we provide experimental evidence for such a violation. We extract photons from a small superoscillatory region near the core of an optical vortex and show that their mean transverse momentum is statistically incompatible with a general bound implied by local momentum conservation. The derivation of this bound requires only the theoretically well-supported assumption that the extraction mechanism does not alter the photons' mean transverse momentum. We also detect photons with high transverse momentum at a rate significantly exceeding that predicted by a model assuming local momentum conservation. Because this violation can be established only counterfactually and through postselection, it does not conflict with relativistic causality. Our results may represent the first example of a distinct form of quantum nonlocality that does not explicitly rely on entanglement.
Carlo Schiano; Bereneice Sephton; Elnaz Darsheshdar; Lorenzo Marrucci; Corrado Lisio; Vincenzo D'Ambrosio
Tailoring Spatial Correlations With Quantum Interference Journal Article
In: LASER & PHOTONICS REVIEWS, vol. 20, no. 11, pp. e02895, 2026.
@article{schiano_tailoring_2026,
title = {Tailoring Spatial Correlations With Quantum Interference},
author = {Carlo Schiano and Bereneice Sephton and Elnaz Darsheshdar and Lorenzo Marrucci and Corrado Lisio and Vincenzo D'Ambrosio},
url = {https://doi.org/10.1002/lpor.202502895},
doi = {10.1002/lpor.202502895},
year = {2026},
date = {2026-06-01},
urldate = {2026-06-01},
journal = {LASER & PHOTONICS REVIEWS},
volume = {20},
number = {11},
pages = {e02895},
abstract = {ABSTRACT
Photon correlations represent a central resource in many quantum optics experiments, with applications ranging from quantum information protocols to sensing. Engineering such correlations is often challenging, especially in multi‐particle scenarios. This work describes an effective method for shaping spatial correlations between photons by patterning their distinguishability in a quantum interference setup. How one may write and edit these bi‐photon correlations between the two output channels of a beam‐splitter is presented, where the information encoded remains hidden from conventional intensity measurements. The scheme presented here offers an easy extension to multiparticle scenarios and facilitates the transmission of high‐dimensional quantum information, opening new avenues for applications in quantum technologies and imaging protocols.},
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ABSTRACT
Photon correlations represent a central resource in many quantum optics experiments, with applications ranging from quantum information protocols to sensing. Engineering such correlations is often challenging, especially in multi‐particle scenarios. This work describes an effective method for shaping spatial correlations between photons by patterning their distinguishability in a quantum interference setup. How one may write and edit these bi‐photon correlations between the two output channels of a beam‐splitter is presented, where the information encoded remains hidden from conventional intensity measurements. The scheme presented here offers an easy extension to multiparticle scenarios and facilitates the transmission of high‐dimensional quantum information, opening new avenues for applications in quantum technologies and imaging protocols.
Photon correlations represent a central resource in many quantum optics experiments, with applications ranging from quantum information protocols to sensing. Engineering such correlations is often challenging, especially in multi‐particle scenarios. This work describes an effective method for shaping spatial correlations between photons by patterning their distinguishability in a quantum interference setup. How one may write and edit these bi‐photon correlations between the two output channels of a beam‐splitter is presented, where the information encoded remains hidden from conventional intensity measurements. The scheme presented here offers an easy extension to multiparticle scenarios and facilitates the transmission of high‐dimensional quantum information, opening new avenues for applications in quantum technologies and imaging protocols.
Francesco Di Colandrea; Lorenzo Marrucci; Filippo Cardano
Skyrmionic Polarization Textures in Structured Dielectric Planar Media Journal Article
In: NANOPHOTONICS, vol. 15, no. 3, pp. e70009, 2026.
@article{di_colandrea_skyrmionic_2026,
title = {Skyrmionic Polarization Textures in Structured Dielectric Planar Media},
author = {Francesco Di Colandrea and Lorenzo Marrucci and Filippo Cardano},
url = {https://doi.org/10.1002/nap2.70009},
doi = {10.1002/nap2.70009},
year = {2026},
date = {2026-02-01},
urldate = {2026-02-01},
journal = {NANOPHOTONICS},
volume = {15},
number = {3},
pages = {e70009},
abstract = {ABSTRACT
Skyrmionic patterns of optical fields have recently emerged across diverse photonic platforms. Here, we show that such textures also arise in the polarization eigenstates of light propagation through flat dielectric devices with an engineered, space‐dependent optic axis orientation. We focus on two‐dimensional periodic structures, where propagation through multiple devices maps onto quantum dynamics on a synthetic optical lattice. Adopting the condensed‐matter framework, a spatial period defines an effective Brillouin zone, and polarization eigenstates can be grouped in two bands, with the role of energy played by the opposite phase delay. When such eigenstates exhibit skyrmionic textures, the corresponding lattice model shows the topology of a Chern insulator. We validate these concepts in a system of three tunable liquid‐crystal metasurfaces. Using machine learning, polarization eigenmodes are reconstructed over one spatial period. We identify configurations of the devices' parameters that lead to topologically nontrivial bands, where we directly observe skyrmionic eigenpolarization textures. We also extract local observables of lattice models, such as the Berry curvature and the quantum metric. We finally report a numerical simulation of an all‐optical quantum Hall effect emerging when light propagates through a sequence of such devices, arranged to mimic the effect of an external force on the lattice.},
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ABSTRACT
Skyrmionic patterns of optical fields have recently emerged across diverse photonic platforms. Here, we show that such textures also arise in the polarization eigenstates of light propagation through flat dielectric devices with an engineered, space‐dependent optic axis orientation. We focus on two‐dimensional periodic structures, where propagation through multiple devices maps onto quantum dynamics on a synthetic optical lattice. Adopting the condensed‐matter framework, a spatial period defines an effective Brillouin zone, and polarization eigenstates can be grouped in two bands, with the role of energy played by the opposite phase delay. When such eigenstates exhibit skyrmionic textures, the corresponding lattice model shows the topology of a Chern insulator. We validate these concepts in a system of three tunable liquid‐crystal metasurfaces. Using machine learning, polarization eigenmodes are reconstructed over one spatial period. We identify configurations of the devices' parameters that lead to topologically nontrivial bands, where we directly observe skyrmionic eigenpolarization textures. We also extract local observables of lattice models, such as the Berry curvature and the quantum metric. We finally report a numerical simulation of an all‐optical quantum Hall effect emerging when light propagates through a sequence of such devices, arranged to mimic the effect of an external force on the lattice.
Skyrmionic patterns of optical fields have recently emerged across diverse photonic platforms. Here, we show that such textures also arise in the polarization eigenstates of light propagation through flat dielectric devices with an engineered, space‐dependent optic axis orientation. We focus on two‐dimensional periodic structures, where propagation through multiple devices maps onto quantum dynamics on a synthetic optical lattice. Adopting the condensed‐matter framework, a spatial period defines an effective Brillouin zone, and polarization eigenstates can be grouped in two bands, with the role of energy played by the opposite phase delay. When such eigenstates exhibit skyrmionic textures, the corresponding lattice model shows the topology of a Chern insulator. We validate these concepts in a system of three tunable liquid‐crystal metasurfaces. Using machine learning, polarization eigenmodes are reconstructed over one spatial period. We identify configurations of the devices' parameters that lead to topologically nontrivial bands, where we directly observe skyrmionic eigenpolarization textures. We also extract local observables of lattice models, such as the Berry curvature and the quantum metric. We finally report a numerical simulation of an all‐optical quantum Hall effect emerging when light propagates through a sequence of such devices, arranged to mimic the effect of an external force on the lattice.
Francesco Di Colandrea; Fabrizio Pavan; Sarvesh Bansal; Paola Savarese; Grazia Di Bello; Giulio De Filippis; Carmine Antonio Perroni; Donato Farina; Filippo Cardano
Tomographic Characterization of Non-Hermitian Hamiltonians in Reciprocal Space Journal Article
In: PHYSICAL REVIEW LETTERS, vol. 137, no. 12, 2026.
@article{<LineBreak> 11588_1065874,
title = {Tomographic Characterization of Non-Hermitian Hamiltonians in Reciprocal Space},
author = {Francesco Di Colandrea and Fabrizio Pavan and Sarvesh Bansal and Paola Savarese and Grazia Di Bello and Giulio De Filippis and Carmine Antonio Perroni and Donato Farina and Filippo Cardano},
url = {https://journals.aps.org/prl/abstract/10.1103/rvhd-vsz8},
doi = {10.1103/rvhd-vsz8},
year = {2026},
date = {2026-01-01},
urldate = {2026-01-01},
journal = {PHYSICAL REVIEW LETTERS},
volume = {137},
number = {12},
abstract = {Non-Hermitian Hamiltonians enrich quantum physics by extending conventional phase diagrams, enabling novel topological phenomena, and realizing exceptional points with applications in quantum sensing. Here, we present a programmable liquid-crystal-based photonic platform for implementing nonunitary quantum walks with topological band structures. The novelty of this platform lies in its direct access to the reciprocal space, which enables us to perform a momentum-resolved characterization of the underlying Hamiltonian. We report a complete process tomography of a single step of several walks, from which we retrieve complex-valued energy bands, resolve exceptional points, and detect the associated parity-time symmetry breaking through eigenvector coalescence. Our Letter offers a powerful complementary route to retrieving topology beyond dynamical measurements.},
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Non-Hermitian Hamiltonians enrich quantum physics by extending conventional phase diagrams, enabling novel topological phenomena, and realizing exceptional points with applications in quantum sensing. Here, we present a programmable liquid-crystal-based photonic platform for implementing nonunitary quantum walks with topological band structures. The novelty of this platform lies in its direct access to the reciprocal space, which enables us to perform a momentum-resolved characterization of the underlying Hamiltonian. We report a complete process tomography of a single step of several walks, from which we retrieve complex-valued energy bands, resolve exceptional points, and detect the associated parity-time symmetry breaking through eigenvector coalescence. Our Letter offers a powerful complementary route to retrieving topology beyond dynamical measurements.
Domenico Paparo; Anna Martinez; Andrea Rubano
Broadband and Intense Terahertz Time-Domain Spectroscopy for Investigating Liquid Solutions Journal Article
In: LIQUIDS, vol. 6, no. 1, 2026.
@article{<LineBreak> 11588_1027634,
title = {Broadband and Intense Terahertz Time-Domain Spectroscopy for Investigating Liquid Solutions},
author = {Domenico Paparo and Anna Martinez and Andrea Rubano},
doi = {10.3390/liquids6010001},
year = {2026},
date = {2026-01-01},
urldate = {2026-01-01},
journal = {LIQUIDS},
volume = {6},
number = {1},
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Rojan Abolhassani; Lukas Scarfe; Francesco Di Colandrea; Alessio D'Errico; Khabat Heshami; Ebrahim Karimi
Investigating the performance of adaptive optics on different bases of spatial modes in turbulent channels Journal Article
In: OPTICS EXPRESS, vol. 34, no. 3, pp. 3732–3743, 2026.
@article{<LineBreak> 11588_1030554,
title = {Investigating the performance of adaptive optics on different bases of spatial modes in turbulent channels},
author = {Rojan Abolhassani and Lukas Scarfe and Francesco Di Colandrea and Alessio D'Errico and Khabat Heshami and Ebrahim Karimi},
url = {https://opg.optica.org/oe/fulltext.cfm?uri=oe-34-3-3732},
doi = {10.1364/OE.582413},
year = {2026},
date = {2026-01-01},
urldate = {2026-01-01},
journal = {OPTICS EXPRESS},
volume = {34},
number = {3},
pages = {3732–3743},
abstract = {Quantum key distribution (QKD) allows secure key exchange based on the principles of quantum mechanics, with higher-dimensional photonic states offering enhanced channel capacity and resilience to noise. Free-space QKD is crucial for global networks where fibres are impractical, but atmospheric turbulence introduces severe states’ distortions, particularly for spatial modes. Adaptive optics (AO) provides a pathway to correct these errors, though its effectiveness depends on the encoding basis. Here, we experimentally evaluate a high-speed AO system for orbital angular momentum (OAM) modes, mutually unbiased bases (MUB), and symmetric, informationally complete, positive operator-valued measures (SIC-POVM) up to dimension d = 8 in a turbulent free-space channel. While OAM states are strongly distorted, their cylindrical symmetry makes them optimally corrected by AO, yielding error rates below QKD security thresholds. MUB and SIC-POVM exhibit greater intrinsic robustness to turbulence but are less precisely corrected; however their performance remains within protocol tolerances. These results establish AO as a key enabler of secure, high-dimensional QKD and highlight the role of basis choice in optimizing resilience and correction.},
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Quantum key distribution (QKD) allows secure key exchange based on the principles of quantum mechanics, with higher-dimensional photonic states offering enhanced channel capacity and resilience to noise. Free-space QKD is crucial for global networks where fibres are impractical, but atmospheric turbulence introduces severe states’ distortions, particularly for spatial modes. Adaptive optics (AO) provides a pathway to correct these errors, though its effectiveness depends on the encoding basis. Here, we experimentally evaluate a high-speed AO system for orbital angular momentum (OAM) modes, mutually unbiased bases (MUB), and symmetric, informationally complete, positive operator-valued measures (SIC-POVM) up to dimension d = 8 in a turbulent free-space channel. While OAM states are strongly distorted, their cylindrical symmetry makes them optimally corrected by AO, yielding error rates below QKD security thresholds. MUB and SIC-POVM exhibit greater intrinsic robustness to turbulence but are less precisely corrected; however their performance remains within protocol tolerances. These results establish AO as a key enabler of secure, high-dimensional QKD and highlight the role of basis choice in optimizing resilience and correction.
Martando Rath; Yu Chen; Daniela Stornaiuolo; Aravind Raji; Alexandre Gloter; Antonio Cassinese; Andrea Rubano; Alessia Sambri; Domenico Paparo; Emiliano Di Gennaro; Jérôme Lecourt; Wilfrid Prellier; Francesco Rosa; Nicholas B. Brookes; Giacomo Ghiringhelli; Daniele Preziosi; Marco Salluzzo
Reconfigurable Ferroelectric‐Like Two‐Dimensional Electron Gas at Room Temperature Journal Article
In: ADVANCED MATERIALS, 2026.
@article{<LineBreak> 11588_1063055,
title = {Reconfigurable Ferroelectric‐Like Two‐Dimensional Electron Gas at Room Temperature},
author = {Martando Rath and Yu Chen and Daniela Stornaiuolo and Aravind Raji and Alexandre Gloter and Antonio Cassinese and Andrea Rubano and Alessia Sambri and Domenico Paparo and Emiliano Di Gennaro and Jérôme Lecourt and Wilfrid Prellier and Francesco Rosa and Nicholas B. Brookes and Giacomo Ghiringhelli and Daniele Preziosi and Marco Salluzzo},
doi = {10.1002/adma.74190},
year = {2026},
date = {2026-01-01},
urldate = {2026-01-01},
journal = {ADVANCED MATERIALS},
abstract = {Engineering ferroelectric two-dimensional electron gases (2DEGs) offers a promising route toward nonvolatile and reconfigurable electronic functionalities, yet room temperature implementations remain scarce. Here, we report a room temperature ferroelectric-like 2DEG at the SrO- (Formula presented.) interface between (001) (Formula presented.) (STO) and (Formula presented.) (KNN) thin films. Robust ferroelectricity is confirmed by piezoforce microscopy, optical second harmonic generation, Nb- (Formula presented.) /Ti- (Formula presented.) edges x-ray linear dichroism, scanning transmission electron microscopy, and macroscopic polarization measurements. The ferroelectric polarization enables nonvolatile control of interfacial transport and the realization of reconfigurable conducting channels with arbitrary geometry at room temperature. The coupling between ferroelectric order and 2DEG conductivity arises from the extension of the polarization into the interfacial unit cells hosting the electron gas. These results establish (Formula presented.) / (Formula presented.) heterostructures as a ferroelectric-like oxide electronic platform, opening pathways for low-power, nonvolatile electronic and spin-orbitronic devices.},
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Engineering ferroelectric two-dimensional electron gases (2DEGs) offers a promising route toward nonvolatile and reconfigurable electronic functionalities, yet room temperature implementations remain scarce. Here, we report a room temperature ferroelectric-like 2DEG at the SrO- (Formula presented.) interface between (001) (Formula presented.) (STO) and (Formula presented.) (KNN) thin films. Robust ferroelectricity is confirmed by piezoforce microscopy, optical second harmonic generation, Nb- (Formula presented.) /Ti- (Formula presented.) edges x-ray linear dichroism, scanning transmission electron microscopy, and macroscopic polarization measurements. The ferroelectric polarization enables nonvolatile control of interfacial transport and the realization of reconfigurable conducting channels with arbitrary geometry at room temperature. The coupling between ferroelectric order and 2DEG conductivity arises from the extension of the polarization into the interfacial unit cells hosting the electron gas. These results establish (Formula presented.) / (Formula presented.) heterostructures as a ferroelectric-like oxide electronic platform, opening pathways for low-power, nonvolatile electronic and spin-orbitronic devices.
Maria Parisi; Verónica Vicuña-Hernández; Antonio Borrielli; Antigone Marino; Michele Bonaldi; Enrico Serra; Domenico Paparo; Andrea Rubano; Sareh Golkar; Bruno Piccirillo; Simona Mosca
Optomechanical Analyzer of Azimuthal Quadratures for Structured Light Journal Article
In: APPLIED SCIENCES, vol. 16, no. 15, 2026, ISSN: 2076-3417.
@article{app16157538,
title = {Optomechanical Analyzer of Azimuthal Quadratures for Structured Light},
author = {Maria Parisi and Verónica Vicuña-Hernández and Antonio Borrielli and Antigone Marino and Michele Bonaldi and Enrico Serra and Domenico Paparo and Andrea Rubano and Sareh Golkar and Bruno Piccirillo and Simona Mosca},
url = {https://www.mdpi.com/2076-3417/16/15/7538},
doi = {10.3390/app16157538},
issn = {2076-3417},
year = {2026},
date = {2026-01-01},
urldate = {2026-01-01},
journal = {APPLIED SCIENCES},
volume = {16},
number = {15},
abstract = {We demonstrate optomechanical spatial projection of azimuthally structured optical beams. The system is based on an ultra-low loss circular membrane integrated into an interferometric setup, which exploits the spatial analogies between the mechanical modes and the structured optical fields. A slight geometric asymmetry, originating from a tiny ellipticity introduced during microfabrication, lifts the degeneracy of the membrane modes, producing a spectrally resolved mechanical doublet composed of two orthogonal eigenmodes. Crucially, this doublet provides a phase-sensitive mechanical reference where the spatial orientation of the optical mode is mapped to a distinct resonance frequency, effectively acting as an optical-spatial-to-mechanical spectral projector. Petal-shaped optical intensity distributions, formed by coherent superpositions of orbital-angular-momentum eigenstates with opposite topological charges and generated via a q-plate, are used to probe the membrane in a readout-only regime, where the motion is thermally excited. By rotating the azimuthal orientation of the optical pattern, we observe a controlled redistribution of spectral weight between the two members of the mechanical doublet. The split doublet, therefore, acts as a two-channel mechanical spatial analyzer for azimuthal quadratures. This mechanism yields maximum sensitivity for a topological charge of ℓ=1, as its two-lobed intensity distribution matches well the fundamental azimuthal mechanical modes. Overall, the system provides a wavelength-independent platform for the projection and processing of structured optical fields. Since the analyzer relies on spatial mode matching rather than optical spectral properties, the system can interface with a wide range of optical sources and channels, making it a potentially relevant platform for future structured-light communication architectures.},
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We demonstrate optomechanical spatial projection of azimuthally structured optical beams. The system is based on an ultra-low loss circular membrane integrated into an interferometric setup, which exploits the spatial analogies between the mechanical modes and the structured optical fields. A slight geometric asymmetry, originating from a tiny ellipticity introduced during microfabrication, lifts the degeneracy of the membrane modes, producing a spectrally resolved mechanical doublet composed of two orthogonal eigenmodes. Crucially, this doublet provides a phase-sensitive mechanical reference where the spatial orientation of the optical mode is mapped to a distinct resonance frequency, effectively acting as an optical-spatial-to-mechanical spectral projector. Petal-shaped optical intensity distributions, formed by coherent superpositions of orbital-angular-momentum eigenstates with opposite topological charges and generated via a q-plate, are used to probe the membrane in a readout-only regime, where the motion is thermally excited. By rotating the azimuthal orientation of the optical pattern, we observe a controlled redistribution of spectral weight between the two members of the mechanical doublet. The split doublet, therefore, acts as a two-channel mechanical spatial analyzer for azimuthal quadratures. This mechanism yields maximum sensitivity for a topological charge of ℓ=1, as its two-lobed intensity distribution matches well the fundamental azimuthal mechanical modes. Overall, the system provides a wavelength-independent platform for the projection and processing of structured optical fields. Since the analyzer relies on spatial mode matching rather than optical spectral properties, the system can interface with a wide range of optical sources and channels, making it a potentially relevant platform for future structured-light communication architectures.
Maria Gorizia Ammendola; Nazanin Dehghan; Lukas Scarfe; Alessio D'Errico; Francesco Di Colandrea; Ebrahim Karimi; Filippo Cardano
Compact and programmable large-scale optical processor in free space Journal Article
In: LIGHT, SCIENCE & APPLICATIONS, vol. 15, no. 1, 2026.
@article{<LineBreak> 11588_1044214,
title = {Compact and programmable large-scale optical processor in free space},
author = {Maria Gorizia Ammendola and Nazanin Dehghan and Lukas Scarfe and Alessio D'Errico and Francesco Di Colandrea and Ebrahim Karimi and Filippo Cardano},
doi = {10.1038/s41377-026-02236-2},
year = {2026},
date = {2026-01-01},
urldate = {2026-01-01},
journal = {LIGHT, SCIENCE & APPLICATIONS},
volume = {15},
number = {1},
abstract = {Photonic circuits are central to classical and quantum information processing. While integrated technologies dominate, free-space architectures are emerging as attractive alternatives, offering broad bandwidth and direct manipulation of optical modes without confinement in waveguides. A key challenge for scalability lies in circuit depth, as the number of layers manipulating the optical field typically grows with the system size. Here, we introduce a programmable free-space photonic platform that implements translation-invariant, high-dimensional unitary transformations using only three layers. Information is encoded in structured light modes defined by circular polarization and quantized transverse momenta, and processed with spatial light modulators interleaved with half-wave plates. We implement unitaries that are equivalent to quantum walks over up to 30 time steps, in one- and two-dimensional lattices, distributing a single input mode across more than 7,000 outputs, where conventional approaches would require tens or hundreds of layers. The platform supports diverse quantum walk dynamics, including disorder, synthetic gauge fields, and topological effects, previously explored only in separate experiments. Using coincidence detection with a time-tagging camera, we show compatibility with quantum optics protocols and provide examples of quantum walks of heralded single photons. These results contribute to establishing free-space optical processors as promising resources for high-dimensional quantum simulation and scalable optical information processing.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Photonic circuits are central to classical and quantum information processing. While integrated technologies dominate, free-space architectures are emerging as attractive alternatives, offering broad bandwidth and direct manipulation of optical modes without confinement in waveguides. A key challenge for scalability lies in circuit depth, as the number of layers manipulating the optical field typically grows with the system size. Here, we introduce a programmable free-space photonic platform that implements translation-invariant, high-dimensional unitary transformations using only three layers. Information is encoded in structured light modes defined by circular polarization and quantized transverse momenta, and processed with spatial light modulators interleaved with half-wave plates. We implement unitaries that are equivalent to quantum walks over up to 30 time steps, in one- and two-dimensional lattices, distributing a single input mode across more than 7,000 outputs, where conventional approaches would require tens or hundreds of layers. The platform supports diverse quantum walk dynamics, including disorder, synthetic gauge fields, and topological effects, previously explored only in separate experiments. Using coincidence detection with a time-tagging camera, we show compatibility with quantum optics protocols and provide examples of quantum walks of heralded single photons. These results contribute to establishing free-space optical processors as promising resources for high-dimensional quantum simulation and scalable optical information processing.
2025
Chandroth P. Jisha; Lorenzo Marrucci; Stefan Nolte; Alessandro Alberucci
Spin-dependent routing of optical beams in the bulk of twisted anisotropic media Journal Article
In: PHYSICAL REVIEW A, vol. 112, no. 4, pp. 043521, 2025.
@article{jisha_spin-dependent_2025,
title = {Spin-dependent routing of optical beams in the bulk of twisted anisotropic media},
author = {Chandroth P. Jisha and Lorenzo Marrucci and Stefan Nolte and Alessandro Alberucci},
url = {https://doi.org/10.1103/jm7q-nxy1},
doi = {10.1103/jm7q-nxy1},
year = {2025},
date = {2025-10-01},
urldate = {2025-10-01},
journal = {PHYSICAL REVIEW A},
volume = {112},
number = {4},
pages = {043521},
abstract = {We theoretically discuss a kind of photonic spin-Hall effect (PSHE) for optical beams propagating inside an inhomogeneously twisted anisotropic material. The rotation angle plays the role of an effective gauge field. When the twisting distribution is odd symmetric, the optical beams move along mirror-symmetric trajectories according to their helicity. Connection of this volumetric PSHE with the geometric phase and the Kapitza effect is elucidated.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We theoretically discuss a kind of photonic spin-Hall effect (PSHE) for optical beams propagating inside an inhomogeneously twisted anisotropic material. The rotation angle plays the role of an effective gauge field. When the twisting distribution is odd symmetric, the optical beams move along mirror-symmetric trajectories according to their helicity. Connection of this volumetric PSHE with the geometric phase and the Kapitza effect is elucidated.
Paola Savarese; Sarvesh Bansal; Maria Gorizia Ammendola; Lorenzo Amato; Raouf Barboza; Bruno Piccirillo; Francesco Di Colandrea; Lorenzo Marrucci; Filippo Cardano
Programmable non-Hermitian photonic quantum walks via dichroic metasurfaces Journal Article
In: APL PHOTONICS, vol. 10, no. 8, pp. 086106, 2025.
@article{savarese_programmable_2025,
title = {Programmable non-Hermitian photonic quantum walks via dichroic metasurfaces},
author = {Paola Savarese and Sarvesh Bansal and Maria Gorizia Ammendola and Lorenzo Amato and Raouf Barboza and Bruno Piccirillo and Francesco Di Colandrea and Lorenzo Marrucci and Filippo Cardano},
url = {https://doi.org/10.1063/5.0274332},
doi = {10.1063/5.0274332},
year = {2025},
date = {2025-08-01},
urldate = {2025-08-01},
journal = {APL PHOTONICS},
volume = {10},
number = {8},
pages = {086106},
abstract = {The evolution of a closed quantum system is described by a unitary operator generated by a Hermitian Hamiltonian. However, when certain degrees of freedom are coupled to an environment, the relevant dynamics can be captured by non-unitary evolution operators, arising from non-Hermitian Hamiltonians. Here we introduce a photonic platform that implements non-unitary quantum walks, commonly used to emulate open-system dynamics, in the synthetic space of light transverse momentum. These walks are realized by propagating light through a series of dichroic liquid-crystal metasurfaces that impart polarization-dependent momentum shifts. The non-unitary behavior stems from dichroic dye molecules with polarization-dependent absorption, whose orientation is coupled to that of the liquid crystals. We demonstrate multiple walks up to five time steps, with adjustable levels of dichroism set by the metasurface voltage, which is controlled remotely. This discrete-time process maps onto two-band tight-binding models with reciprocal yet non-Hermitian nearest-neighbor couplings, corresponding to a less-studied class of non-Hermitian systems. Our platform broadens the range of optical simulators for controlled investigations of non-Hermitian quantum dynamics.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The evolution of a closed quantum system is described by a unitary operator generated by a Hermitian Hamiltonian. However, when certain degrees of freedom are coupled to an environment, the relevant dynamics can be captured by non-unitary evolution operators, arising from non-Hermitian Hamiltonians. Here we introduce a photonic platform that implements non-unitary quantum walks, commonly used to emulate open-system dynamics, in the synthetic space of light transverse momentum. These walks are realized by propagating light through a series of dichroic liquid-crystal metasurfaces that impart polarization-dependent momentum shifts. The non-unitary behavior stems from dichroic dye molecules with polarization-dependent absorption, whose orientation is coupled to that of the liquid crystals. We demonstrate multiple walks up to five time steps, with adjustable levels of dichroism set by the metasurface voltage, which is controlled remotely. This discrete-time process maps onto two-band tight-binding models with reciprocal yet non-Hermitian nearest-neighbor couplings, corresponding to a less-studied class of non-Hermitian systems. Our platform broadens the range of optical simulators for controlled investigations of non-Hermitian quantum dynamics.
Radhika Prasad; Nilakshi Senapati; Suman Karan; Abhinandan Bhattacharjee; Bruno Piccirillo; Miguel A. Alonso; Anand K. Jha
Experimental technique for measuring radial coherence Journal Article
In: OPTICS EXPRESS, vol. 33, pp. 11693–11701, 2025.
@article{<LineBreak> 11588_997148,
title = {Experimental technique for measuring radial coherence},
author = {Radhika Prasad and Nilakshi Senapati and Suman Karan and Abhinandan Bhattacharjee and Bruno Piccirillo and Miguel A. Alonso and Anand K. Jha},
doi = {10.1364/OE.544628},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {OPTICS EXPRESS},
volume = {33},
pages = {11693–11701},
abstract = {Coherence refers to correlations between field vibrations at two separate points in degrees of freedom such as space, time, and polarization. In the context of space, coherence theory has been formulated between two transverse positions which can be described either in the Cartesian coordinates or in the cylindrical coordinates. When expressed in cylindrical coordinates, spatial coherence is described in terms of azimuthal and radial coordinates. The description of spatial coherence in radial degree of freedom has been formulated only recently in JOSA A 40, 411 (2023). In the present article, we demonstrate an efficient experimental technique for measuring radial coherence, and we report measurement of radial coherence of two different types of radially partially coherent optical fields.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Coherence refers to correlations between field vibrations at two separate points in degrees of freedom such as space, time, and polarization. In the context of space, coherence theory has been formulated between two transverse positions which can be described either in the Cartesian coordinates or in the cylindrical coordinates. When expressed in cylindrical coordinates, spatial coherence is described in terms of azimuthal and radial coordinates. The description of spatial coherence in radial degree of freedom has been formulated only recently in JOSA A 40, 411 (2023). In the present article, we demonstrate an efficient experimental technique for measuring radial coherence, and we report measurement of radial coherence of two different types of radially partially coherent optical fields.
Domenico Paparo; Anna Martinez; Andrea Rubano
Coherent Terahertz Hyper‐Raman Spectroscopy Journal Article
In: JOURNAL OF RAMAN SPECTROSCOPY, no. 9, 2025.
@article{<LineBreak> 11588_1004008,
title = {Coherent Terahertz Hyper‐Raman Spectroscopy},
author = {Domenico Paparo and Anna Martinez and Andrea Rubano},
doi = {10.1002/jrs.6787},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {JOURNAL OF RAMAN SPECTROSCOPY},
number = {9},
abstract = {In this paper, we review our recent discovery of a novel nonlinear effect in the terahertz frequency range, which we have termed terahertz hyper-Raman (THYR) spectroscopy. This technique shares many characteristics with conventional hyper-Raman spectroscopy but is applied within the THz spectrum. By utilizing intense terahertz pulses, THYR allows for the investigation of low-energy excitations in materials. Using crystalline quartz as a model, we demonstrate that THYR can simultaneously detect phonon modes, including those outside the Brillouin zone, as well as infrared-active vibrations and polaritons, offering capabilities beyond traditional Raman and infrared spectroscopy. Additionally, we discuss our recent progress toward the generation of circularly polarized THz pulses, enhancing the potential of THYR to study chiral excitations. These developments position THYR as a powerful tool for advancing nonlinear optics and material analysis. As we approach the centennial anniversary of the discovery of the Raman effect, we will show that our technique can bring a new wave of innovation to the field by merging the core principles of Raman spectroscopy with the rapidly advancing field of THz optics and technology.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this paper, we review our recent discovery of a novel nonlinear effect in the terahertz frequency range, which we have termed terahertz hyper-Raman (THYR) spectroscopy. This technique shares many characteristics with conventional hyper-Raman spectroscopy but is applied within the THz spectrum. By utilizing intense terahertz pulses, THYR allows for the investigation of low-energy excitations in materials. Using crystalline quartz as a model, we demonstrate that THYR can simultaneously detect phonon modes, including those outside the Brillouin zone, as well as infrared-active vibrations and polaritons, offering capabilities beyond traditional Raman and infrared spectroscopy. Additionally, we discuss our recent progress toward the generation of circularly polarized THz pulses, enhancing the potential of THYR to study chiral excitations. These developments position THYR as a powerful tool for advancing nonlinear optics and material analysis. As we approach the centennial anniversary of the discovery of the Raman effect, we will show that our technique can bring a new wave of innovation to the field by merging the core principles of Raman spectroscopy with the rapidly advancing field of THz optics and technology.
Mehrdad Ghiasabadi Farahani; Alberto Quintana; Tingfeng Song; Rohit Kumar; Andrea Rubano; Ali Faizan; Florencio Sánchez; Ignasi Fina
Dual Ferroelectric Polarization and Dielectric Response Improvement in Epitaxial Hf0.5Zr0.5O2/HfO2 Nanolaminates Journal Article
In: ACS APPLIED MATERIALS & INTERFACES, vol. 17, no. 2, pp. 3570–3577, 2025.
@article{<LineBreak> 11588_1004007,
title = {Dual Ferroelectric Polarization and Dielectric Response Improvement in Epitaxial Hf0.5Zr0.5O2/HfO2 Nanolaminates},
author = {Mehrdad Ghiasabadi Farahani and Alberto Quintana and Tingfeng Song and Rohit Kumar and Andrea Rubano and Ali Faizan and Florencio Sánchez and Ignasi Fina},
doi = {10.1021/acsami.4c15867},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {ACS APPLIED MATERIALS & INTERFACES},
volume = {17},
number = {2},
pages = {3570–3577},
abstract = {Nanolaminates based on ferroelectric polycrystalline doped HfO2 have gained interest because those compounds show enhanced functional properties. Here, we achieve coexisting improvement of remanent polarization and dielectric permittivity in wake-up-free epitaxial Hf0.5Zr0.5O2/HfO2 nanolaminates with different numbers of HfO2 nanolayers if compared with Hf0.5Zr0.5O2 single films of equivalent thickness or other reported polycrystalline nanolaminates. Comprehensive structural characterization reveals that the origin of the enhancement must be the larger amount of the orthorhombic phase in the nanolaminates. The retention of nanolaminates is greater than that of Hf0.5Zr0.5O2 single films; however, fatigue is larger and ferroelectric switching is slower in the nanolaminates compared with single layers. The present work reveals nanolamination in high-quality films as a strategy to increase dielectric permittivity without important degradation of other functional properties.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Nanolaminates based on ferroelectric polycrystalline doped HfO2 have gained interest because those compounds show enhanced functional properties. Here, we achieve coexisting improvement of remanent polarization and dielectric permittivity in wake-up-free epitaxial Hf0.5Zr0.5O2/HfO2 nanolaminates with different numbers of HfO2 nanolayers if compared with Hf0.5Zr0.5O2 single films of equivalent thickness or other reported polycrystalline nanolaminates. Comprehensive structural characterization reveals that the origin of the enhancement must be the larger amount of the orthorhombic phase in the nanolaminates. The retention of nanolaminates is greater than that of Hf0.5Zr0.5O2 single films; however, fatigue is larger and ferroelectric switching is slower in the nanolaminates compared with single layers. The present work reveals nanolamination in high-quality films as a strategy to increase dielectric permittivity without important degradation of other functional properties.
F. Di Colandrea; T. Jaouni; J. Grace; D. Paneru; M. Arienzo; A. D'Errico; E. Karimi
Engineering qubit dynamics in open systems with photonic synthetic lattices Journal Article
In: PHYSICAL REVIEW RESEARCH, vol. 7, no. 2, 2025.
@article{<LineBreak> 11588_1007337,
title = {Engineering qubit dynamics in open systems with photonic synthetic lattices},
author = {F. Di Colandrea and T. Jaouni and J. Grace and D. Paneru and M. Arienzo and A. D'Errico and E. Karimi},
doi = {10.1103/PhysRevResearch.7.023236},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {PHYSICAL REVIEW RESEARCH},
volume = {7},
number = {2},
abstract = {The evolution of a quantum system interacting with an environment can be described as a unitary process acting on both the system and the environment. In this framework, the system's evolution can be predicted by tracing out the environmental degrees of freedom. Here, we establish a precise mapping between the global unitary dynamics and the quantum operation involving the system, wherein the system is a single qubit, and the environment is modeled as a discrete lattice space. This approach enables the implementation of arbitrary noise operations on single-polarization qubits using a minimal set of three liquid-crystal metasurfaces, whose transverse distribution of the optic axes can be patterned to reproduce the target process. We experimentally validate this method by simulating common noise processes, such as phase errors and depolarization. Besides providing a practical solution for quantum state purification, this work demonstrates a versatile approach for the simulation of open qubit dynamics, with potential implications for quantum error correction and environment-induced quantum phase transitions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The evolution of a quantum system interacting with an environment can be described as a unitary process acting on both the system and the environment. In this framework, the system's evolution can be predicted by tracing out the environmental degrees of freedom. Here, we establish a precise mapping between the global unitary dynamics and the quantum operation involving the system, wherein the system is a single qubit, and the environment is modeled as a discrete lattice space. This approach enables the implementation of arbitrary noise operations on single-polarization qubits using a minimal set of three liquid-crystal metasurfaces, whose transverse distribution of the optic axes can be patterned to reproduce the target process. We experimentally validate this method by simulating common noise processes, such as phase errors and depolarization. Besides providing a practical solution for quantum state purification, this work demonstrates a versatile approach for the simulation of open qubit dynamics, with potential implications for quantum error correction and environment-induced quantum phase transitions.
Xiaoqin Gao; Dilip Paneru; Francesco Di Colandrea; Yingwen Zhang; Ebrahim Karimi
Generation of the complete Bell basis via Hong-Ou-Mandel interference of vector modes Journal Article
In: PHYSICAL REVIEW A, no. 1, 2025.
@article{<LineBreak> 11588_1007336,
title = {Generation of the complete Bell basis via Hong-Ou-Mandel interference of vector modes},
author = {Xiaoqin Gao and Dilip Paneru and Francesco Di Colandrea and Yingwen Zhang and Ebrahim Karimi},
url = {https://journals.aps.org/pra/abstract/10.1103/dcxb-ql1r},
doi = {10.1103/dcxb-ql1r},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {PHYSICAL REVIEW A},
number = {1},
abstract = {Optical vector modes (VMs), characterized by spatially varying polarization distributions, have become essential tools across microscopy, metrology, optical trapping, nanophotonics, and optical communications. Here, we investigate the Hong-Ou-Mandel (HOM) interference of VMs providing a full spatial characterization of the output state. We find that, by carefully selecting the input VMs, it is possible to simultaneously observe all four polarization Bell states and their superpositions in the spatially varying polarization pattern of the two photons. These results represent a significant step in advancing our understanding of HOM interference within structured photons, offering promising avenues for high-dimensional quantum information processing and, in particular, high-dimensional quantum communication, quantum sensing, and advanced photonic technologies reliant on tailored quantum states of light.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Optical vector modes (VMs), characterized by spatially varying polarization distributions, have become essential tools across microscopy, metrology, optical trapping, nanophotonics, and optical communications. Here, we investigate the Hong-Ou-Mandel (HOM) interference of VMs providing a full spatial characterization of the output state. We find that, by carefully selecting the input VMs, it is possible to simultaneously observe all four polarization Bell states and their superpositions in the spatially varying polarization pattern of the two photons. These results represent a significant step in advancing our understanding of HOM interference within structured photons, offering promising avenues for high-dimensional quantum information processing and, in particular, high-dimensional quantum communication, quantum sensing, and advanced photonic technologies reliant on tailored quantum states of light.
Lukas Scarfe; Rojan Abolhassani; Frédéric Bouchard; Aaron Z. Goldberg; Khabat Heshami; Francesco Di Colandrea; Ebrahim Karimi
High-dimensional quantum key distribution with Qubit-like states Journal Article
In: COMMUNICATIONS PHYSICS, vol. 8, no. 1, 2025.
@article{<LineBreak> 11588_1021939,
title = {High-dimensional quantum key distribution with Qubit-like states},
author = {Lukas Scarfe and Rojan Abolhassani and Frédéric Bouchard and Aaron Z. Goldberg and Khabat Heshami and Francesco Di Colandrea and Ebrahim Karimi},
doi = {10.1038/s42005-025-02376-8},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {COMMUNICATIONS PHYSICS},
volume = {8},
number = {1},
abstract = {Quantum key distribution (QKD) protocols most often use two conjugate bases in order to verify the security of the quantum channel. In the majority of protocols, these bases are mutually unbiased to one another, which is to say they are formed from balanced superpositions of the entire set of states in the opposing basis. Here, we introduce a high-dimensional QKD protocol using qubit-like states, referred to as Fourier-qubits (or F-qubits). In our scheme, each F-qubit is a superposition of only two computational basis states with a relative phase that can take d distinct values, where d is the dimension of the computational basis. This non-mutually-unbiased approach allows us to bound the information leaked to an eavesdropper, maintaining security in high-dimensional quantum systems despite the states’ seemingly two-dimensional nature. By simplifying state preparation and measurement, our protocol offers a practical alternative for secure high-dimensional quantum communications. We experimentally demonstrate this protocol for a noisy high-dimensional QKD channel using the orbital angular momentum degree of freedom of light and discuss the potential benefits for encoding in other degrees of freedom.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Quantum key distribution (QKD) protocols most often use two conjugate bases in order to verify the security of the quantum channel. In the majority of protocols, these bases are mutually unbiased to one another, which is to say they are formed from balanced superpositions of the entire set of states in the opposing basis. Here, we introduce a high-dimensional QKD protocol using qubit-like states, referred to as Fourier-qubits (or F-qubits). In our scheme, each F-qubit is a superposition of only two computational basis states with a relative phase that can take d distinct values, where d is the dimension of the computational basis. This non-mutually-unbiased approach allows us to bound the information leaked to an eavesdropper, maintaining security in high-dimensional quantum systems despite the states’ seemingly two-dimensional nature. By simplifying state preparation and measurement, our protocol offers a practical alternative for secure high-dimensional quantum communications. We experimentally demonstrate this protocol for a noisy high-dimensional QKD channel using the orbital angular momentum degree of freedom of light and discuss the potential benefits for encoding in other degrees of freedom.
Dilip Paneru; Francesco Di Colandrea; Alessio D'Errico; Ebrahim Karimi
Nonlocal transfer of high-dimensional unitary operations Journal Article
In: QUANTUM, vol. 9, 2025.
@article{<LineBreak> 11588_1013338,
title = {Nonlocal transfer of high-dimensional unitary operations},
author = {Dilip Paneru and Francesco Di Colandrea and Alessio D'Errico and Ebrahim Karimi},
url = {https://quantum-journal.org/papers/q-2025-09-11-1855/},
doi = {10.22331/q-2025-09-11-1855},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {QUANTUM},
volume = {9},
abstract = {Highly correlated biphoton states are powerful resources in quantum optics, both for fundamental tests of the theory and practical applications. In particular, high-dimensional spatial correlation has been used in several quantum information processing and sensing tasks, for instance, in ghost imaging experiments along with several quantum key distribution protocols. Here, we introduce a technique that exploits spatial correlations, whereby one can nonlocally access the result of an arbitrary unitary operator on an arbitrary input state without the need to perform any operation themselves. The method is experimentally validated on a set of spatially periodic unitary operations in one-dimensional and two-dimensional spaces. Our findings pave the way for efficiently distributing quantum simulations and computations in future instances of quantum networks where users with limited resources can nonlocally access the results of complex unitary transformations via a centrally located quantum processor.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Highly correlated biphoton states are powerful resources in quantum optics, both for fundamental tests of the theory and practical applications. In particular, high-dimensional spatial correlation has been used in several quantum information processing and sensing tasks, for instance, in ghost imaging experiments along with several quantum key distribution protocols. Here, we introduce a technique that exploits spatial correlations, whereby one can nonlocally access the result of an arbitrary unitary operator on an arbitrary input state without the need to perform any operation themselves. The method is experimentally validated on a set of spatially periodic unitary operations in one-dimensional and two-dimensional spaces. Our findings pave the way for efficiently distributing quantum simulations and computations in future instances of quantum networks where users with limited resources can nonlocally access the results of complex unitary transformations via a centrally located quantum processor.
Tareq Jaouni; Lukas Scarfe; Frédéric Bouchard; Mario Krenn; Khabat Heshami; Francesco Di Colandrea; Ebrahim Karimi
Predicting atmospheric turbulence for secure quantum communications in free space Journal Article
In: OPTICS EXPRESS, vol. 33, no. 5, pp. 10759–10776, 2025.
@article{<LineBreak> 11588_1000434,
title = {Predicting atmospheric turbulence for secure quantum communications in free space},
author = {Tareq Jaouni and Lukas Scarfe and Frédéric Bouchard and Mario Krenn and Khabat Heshami and Francesco Di Colandrea and Ebrahim Karimi},
doi = {10.1364/OE.546606},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {OPTICS EXPRESS},
volume = {33},
number = {5},
pages = {10759–10776},
abstract = {Atmospheric turbulence is the main barrier to large-scale free-space quantum communication networks. Aberrations distort optical information carriers, thus limiting or preventing the possibility of establishing a secure link between two parties. For this reason, forecasting the turbulence strength within an optical channel is highly desirable, as it allows for knowing the optimal timing to establish a secure link in advance. Here, we train a recurrent neural network, TAROQQO, to predict the turbulence strength within a free-space channel. The training is based on weather and turbulence data collected over 9 months for a 5.4 km intra-city free-space link across the City of Ottawa. The implications of accurate predictions from our network are demonstrated in a simulated high-dimensional quantum key distribution protocol based on orbital angular momentum states of light across different turbulence regimes. TAROQQO will be crucial in validating a free-space channel to optimally route the key exchange for secure communications in real experimental scenarios.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Atmospheric turbulence is the main barrier to large-scale free-space quantum communication networks. Aberrations distort optical information carriers, thus limiting or preventing the possibility of establishing a secure link between two parties. For this reason, forecasting the turbulence strength within an optical channel is highly desirable, as it allows for knowing the optimal timing to establish a secure link in advance. Here, we train a recurrent neural network, TAROQQO, to predict the turbulence strength within a free-space channel. The training is based on weather and turbulence data collected over 9 months for a 5.4 km intra-city free-space link across the City of Ottawa. The implications of accurate predictions from our network are demonstrated in a simulated high-dimensional quantum key distribution protocol based on orbital angular momentum states of light across different turbulence regimes. TAROQQO will be crucial in validating a free-space channel to optimally route the key exchange for secure communications in real experimental scenarios.
Alessia Sambri; Yu Chen; Federico Mazzola; Emiliano Di Gennaro; Andrea Rubano; Martando Rath; Domenico Paparo; Marco Caputo; Alla Chikina; Deepak Kumar; Vladimir N. Strocov; Marco Salluzzo; Fabio Miletto Granozio
Signatures of Polar Metal Phase in the Quasi-2D Electron System in PLD-Grown Amorphous-Epitaxial Oxide Heterostructures Journal Article
In: NANO LETTERS, vol. 25, no. 36, pp. 13608–13613, 2025.
@article{<LineBreak> 11588_1021364,
title = {Signatures of Polar Metal Phase in the Quasi-2D Electron System in PLD-Grown Amorphous-Epitaxial Oxide Heterostructures},
author = {Alessia Sambri and Yu Chen and Federico Mazzola and Emiliano Di Gennaro and Andrea Rubano and Martando Rath and Domenico Paparo and Marco Caputo and Alla Chikina and Deepak Kumar and Vladimir N. Strocov and Marco Salluzzo and Fabio Miletto Granozio},
doi = {10.1021/acs.nanolett.5c03409},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {NANO LETTERS},
volume = {25},
number = {36},
pages = {13608–13613},
abstract = {For years, itinerant charge carriers in ferroelectric insulators were believed to completely quench ferroelectricity. Recent breakthroughs, however, demonstrated the existence of a novel class of quasi-two-dimensional polar metals with promising applications in nonvolatile electronics and spintronics. Here, by combining temperature-dependent magnetotransport measurements, optical second harmonic generation (SHG), resonant photoemission spectroscopy (ResPES), and X-ray absorption spectroscopy (XAS), we report on the properties of a BaTiO3-based oxide heterostructure, sustaining a persistent polar displacement in the BaTiO3layer while supporting a two-dimensional electron gas. This suggests that the oxide heterostructure may operate as a polar metal system, paving the way for new developments in oxide-based electronics.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
For years, itinerant charge carriers in ferroelectric insulators were believed to completely quench ferroelectricity. Recent breakthroughs, however, demonstrated the existence of a novel class of quasi-two-dimensional polar metals with promising applications in nonvolatile electronics and spintronics. Here, by combining temperature-dependent magnetotransport measurements, optical second harmonic generation (SHG), resonant photoemission spectroscopy (ResPES), and X-ray absorption spectroscopy (XAS), we report on the properties of a BaTiO3-based oxide heterostructure, sustaining a persistent polar displacement in the BaTiO3layer while supporting a two-dimensional electron gas. This suggests that the oxide heterostructure may operate as a polar metal system, paving the way for new developments in oxide-based electronics.
Ruqyyah Mushtaq; Chiara Gambardella; Roberta Miroglio; Fabio Novelli; Melania Paturzo; Andrea Rubano; Angela Sardo; Sergio Balzano; Domenico Paparo
Using diatom chain length as a bioindicator of heavy-metals contamination in marine environments Journal Article
In: JOURNAL OF HAZARDOUS MATERIALS, vol. 484, 2025.
@article{<LineBreak> 11588_1004006,
title = {Using diatom chain length as a bioindicator of heavy-metals contamination in marine environments},
author = {Ruqyyah Mushtaq and Chiara Gambardella and Roberta Miroglio and Fabio Novelli and Melania Paturzo and Andrea Rubano and Angela Sardo and Sergio Balzano and Domenico Paparo},
doi = {10.1016/j.jhazmat.2024.136732},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {JOURNAL OF HAZARDOUS MATERIALS},
volume = {484},
abstract = {The increasing release of toxic heavy metals into marine environments poses significant risks due to their persistence and bioaccumulation. Diatoms are ideal bioindicators because of their sensitivity to environmental changes. Despite traditional methods for detecting these persistent pollutants effectively identify composition and concentration, they are time-consuming, they often require the use of harmful reagents, and do not allow a fast assessment of detrimental impacts on marine organisms. To fill this gap, we have successfully investigated the toxicity of different heavy metals in the marine diatom Skeletonema pseudocostatum thanks to a newly developed high-power terahertz (THz) spectrometer. By combining THz spectroscopy, microscopy and ecotoxicological assays, we found that the formation of long diatom chains is significantly inhibited by the presence of lead, copper, and chromium, which disrupt their metabolism. Although the THz absorption and refractive index spectra were not affected by diatom concentration in undoped samples, THz frequencies were highly sensitive to changes in diatom chain length due to heavy metals exposure. These findings suggest that this approach allows to investigate the biochemical processes involved in chain formation in S. pseudocostatum and related algae. THz spectroscopy could therefore provide deeper insights into the microscopic metabolic activity of diatoms, addressing key biochemical questions surrounding these organisms. Furthermore, we propose this novel approach for environmental pollution monitoring, since it could provide a rapid, harmless and sensitive detection method to assess heavy metal toxicity in marine diatoms, key organisms at the basis of the trophic chain.},
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The increasing release of toxic heavy metals into marine environments poses significant risks due to their persistence and bioaccumulation. Diatoms are ideal bioindicators because of their sensitivity to environmental changes. Despite traditional methods for detecting these persistent pollutants effectively identify composition and concentration, they are time-consuming, they often require the use of harmful reagents, and do not allow a fast assessment of detrimental impacts on marine organisms. To fill this gap, we have successfully investigated the toxicity of different heavy metals in the marine diatom Skeletonema pseudocostatum thanks to a newly developed high-power terahertz (THz) spectrometer. By combining THz spectroscopy, microscopy and ecotoxicological assays, we found that the formation of long diatom chains is significantly inhibited by the presence of lead, copper, and chromium, which disrupt their metabolism. Although the THz absorption and refractive index spectra were not affected by diatom concentration in undoped samples, THz frequencies were highly sensitive to changes in diatom chain length due to heavy metals exposure. These findings suggest that this approach allows to investigate the biochemical processes involved in chain formation in S. pseudocostatum and related algae. THz spectroscopy could therefore provide deeper insights into the microscopic metabolic activity of diatoms, addressing key biochemical questions surrounding these organisms. Furthermore, we propose this novel approach for environmental pollution monitoring, since it could provide a rapid, harmless and sensitive detection method to assess heavy metal toxicity in marine diatoms, key organisms at the basis of the trophic chain.
M. G. Ammendola; F. Di Colandrea; L. Marrucci; F. Cardano
Large-scale free-space photonic circuits in two dimensions Journal Article
In: ADVANCED PHOTONICS, vol. 7, no. 1, 2025.
@article{<LineBreak> 11588_1000554,
title = {Large-scale free-space photonic circuits in two dimensions},
author = {M. G. Ammendola and F. Di Colandrea and L. Marrucci and F. Cardano},
url = {https://www.spiedigitallibrary.org/journals/advanced-photonics/volume-7/issue-01/016006/Large-scale-free-space-photonic-circuits-in-two-dimensions/10.1117/1.AP.7.1.016006.full},
doi = {10.1117/1.AP.7.1.016006},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {ADVANCED PHOTONICS},
volume = {7},
number = {1},
abstract = {Photonic circuits, engineered to couple optical modes according to a specific map, serve as processors for classical and quantum light. The number of components typically scales with that of processed modes, thus correlating system size, circuit complexity, and optical losses. We present a photonic-circuit technology implementing large-scale unitary maps in free space, coupling a single input to hundreds of output modes in a two-dimensional compact layout. The map corresponds to a quantum walk of structured photons, realized through light propagation in three liquid-crystal metasurfaces, having their optic axes artificially patterned. Theoretically, the walk length and the number of connected modes can be arbitrary while keeping losses constant. The patterns can be designed to replicate multiple unitary maps. We also discuss limited reconfigurability by adjusting the overall birefringence and the relative displacement of the optical elements. These results lay the basis for the design of low-loss nonintegrated photonic circuits, primarily for manipulating multiphoton states in quantum regimes.},
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Photonic circuits, engineered to couple optical modes according to a specific map, serve as processors for classical and quantum light. The number of components typically scales with that of processed modes, thus correlating system size, circuit complexity, and optical losses. We present a photonic-circuit technology implementing large-scale unitary maps in free space, coupling a single input to hundreds of output modes in a two-dimensional compact layout. The map corresponds to a quantum walk of structured photons, realized through light propagation in three liquid-crystal metasurfaces, having their optic axes artificially patterned. Theoretically, the walk length and the number of connected modes can be arbitrary while keeping losses constant. The patterns can be designed to replicate multiple unitary maps. We also discuss limited reconfigurability by adjusting the overall birefringence and the relative displacement of the optical elements. These results lay the basis for the design of low-loss nonintegrated photonic circuits, primarily for manipulating multiphoton states in quantum regimes.
Maria Gorizia Ammendola; Francesco Di Colandrea; Lorenzo Marrucci; Filippo Cardano
Large-scale 2D mode couplers via liquid-crystal metasurfaces Proceedings Article
In: PROCEEDINGS OF SPIE – The International Society for Optical Engineering, SPIE, 2025.
@inproceedings{<LineBreak> 11588_1004582,
title = {Large-scale 2D mode couplers via liquid-crystal metasurfaces},
author = {Maria Gorizia Ammendola and Francesco Di Colandrea and Lorenzo Marrucci and Filippo Cardano},
doi = {10.1117/12.3040927},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
booktitle = {PROCEEDINGS OF SPIE - The International Society for Optical Engineering},
volume = {13391},
publisher = {SPIE},
abstract = {Optical degrees of freedom, such as those associated with spatial, spectro-temporal, or polarization features of the optical field, s erve a s a c onvenient r esource f or e ncoding i nformation. T he a bundance o f t ools f or their accurate manipulation established photonics as a versatile platform for both classical and quantum information processing tasks. Optical processors based on linear circuits, performing a variety of tasks, are often referred to as photonic circuits, in analogy with canonical circuits processing electrical signals. Here we demonstrate a compact photonic circuit in free space that implements all-optical mode-coupling operations in two spatial dimensions, operating in large-scale regimes. This provides a valuable alternative to the traditional integrated waveguides approach to optical information processing. We tested it by implementing unitary transformations associated with 2D quantum walks on transverse modes of structured light.},
keywords = {},
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Optical degrees of freedom, such as those associated with spatial, spectro-temporal, or polarization features of the optical field, s erve a s a c onvenient r esource f or e ncoding i nformation. T he a bundance o f t ools f or their accurate manipulation established photonics as a versatile platform for both classical and quantum information processing tasks. Optical processors based on linear circuits, performing a variety of tasks, are often referred to as photonic circuits, in analogy with canonical circuits processing electrical signals. Here we demonstrate a compact photonic circuit in free space that implements all-optical mode-coupling operations in two spatial dimensions, operating in large-scale regimes. This provides a valuable alternative to the traditional integrated waveguides approach to optical information processing. We tested it by implementing unitary transformations associated with 2D quantum walks on transverse modes of structured light.
Paola Savarese; Sarvesh Bansal; Maria Gorizia Ammendola; Raouf Barboza; Marcella Salvatore; Stefano Luigi Oscurato; Bruno Piccirillo; Francesco Di Colandrea; Lorenzo Marrucci; Filippo Cardano
Electrically tunable liquid-crystal metasurfaces with patterned birefringence and dichroism Journal Article
In: APL PHOTONICS, vol. 10, no. 5, 2025.
@article{<LineBreak> 11588_1004581,
title = {Electrically tunable liquid-crystal metasurfaces with patterned birefringence and dichroism},
author = {Paola Savarese and Sarvesh Bansal and Maria Gorizia Ammendola and Raouf Barboza and Marcella Salvatore and Stefano Luigi Oscurato and Bruno Piccirillo and Francesco Di Colandrea and Lorenzo Marrucci and Filippo Cardano},
doi = {10.1063/5.0261491},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {APL PHOTONICS},
volume = {10},
number = {5},
abstract = {Light propagation through artificially patterned anisotropic materials, such as dielectric metasurfaces, enables precise control of the spatio-vectorial properties of optical fields using highly transparent, thin, and flat optical elements. Liquid-crystal cells are a common realization of such devices. Optical losses are typically assumed to be polarization-independent and are therefore often overlooked in modeling these systems. In this work, we introduce electrically tunable liquid-crystal metasurfaces with patterned birefringence and dichroism, achieved by incorporating dichroic dye molecules into the liquid-crystal mixture. These dye molecules align with the liquid crystal, effectively coupling birefringence and dichroism effects. The behavior of these metasurfaces is described using non-unitary Jones matrices, validated through polarimetric measurements. In the case of devices that are patterned to form polarization gratings, we also characterize the diffraction efficiency as a function of the dichroism and birefringence parameters, which can be tuned jointly by applying an electric field across the cell. This study not only introduces a new class of optical components but also deepens our understanding of light propagation through anisotropic materials, where dichroism can naturally arise from bulk material properties or from reflection and transmission laws at their interfaces.},
keywords = {},
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Light propagation through artificially patterned anisotropic materials, such as dielectric metasurfaces, enables precise control of the spatio-vectorial properties of optical fields using highly transparent, thin, and flat optical elements. Liquid-crystal cells are a common realization of such devices. Optical losses are typically assumed to be polarization-independent and are therefore often overlooked in modeling these systems. In this work, we introduce electrically tunable liquid-crystal metasurfaces with patterned birefringence and dichroism, achieved by incorporating dichroic dye molecules into the liquid-crystal mixture. These dye molecules align with the liquid crystal, effectively coupling birefringence and dichroism effects. The behavior of these metasurfaces is described using non-unitary Jones matrices, validated through polarimetric measurements. In the case of devices that are patterned to form polarization gratings, we also characterize the diffraction efficiency as a function of the dichroism and birefringence parameters, which can be tuned jointly by applying an electric field across the cell. This study not only introduces a new class of optical components but also deepens our understanding of light propagation through anisotropic materials, where dichroism can naturally arise from bulk material properties or from reflection and transmission laws at their interfaces.
Filippo Cardano; Lorenzo Marrucci
Twisting entangled photons on a chip Journal Article
In: NATURE PHOTONICS, vol. 19, no. 5, pp. 447–449, 2025.
@article{<LineBreak> 11588_1004579,
title = {Twisting entangled photons on a chip},
author = {Filippo Cardano and Lorenzo Marrucci},
doi = {10.1038/s41566-025-01648-7},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {NATURE PHOTONICS},
volume = {19},
number = {5},
pages = {447–449},
abstract = {A programmable quantum chip has been developed that generates, manipulates, and launches five-dimensional entangled photons into free-space channels, encoded as optical vortex modes, thus bridging the worlds of integrated and free-space quantum photonics.},
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A programmable quantum chip has been developed that generates, manipulates, and launches five-dimensional entangled photons into free-space channels, encoded as optical vortex modes, thus bridging the worlds of integrated and free-space quantum photonics.
Bereneice Sephton; Carlo Schiano; Lorenzo Marrucci; Corrado Lisio; Vincenzo D’Ambrosio
Engineering correlations with a spatially structured quantum eraser Proceedings Article
In: FRONTIERS IN OPTICS, pp. FTh1E–4, Optica Publishing Group, 2025.
@inproceedings{sephton_engineering_2025,
title = {Engineering correlations with a spatially structured quantum eraser},
author = {Bereneice Sephton and Carlo Schiano and Lorenzo Marrucci and Corrado Lisio and Vincenzo D’Ambrosio},
url = {https://opg.optica.org/abstract.cfm?uri=fio-2025-FTh1E.4},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
booktitle = {FRONTIERS IN OPTICS},
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Chandroth P. Jisha; Lorenzo Marrucci; Stefan Nolte; Alessandro Alberucci
Photonic spin-Hall effect in bulk twisted anisotropic media Proceedings Article
In: 2025 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), pp. 1–1, IEEE, 2025.
@inproceedings{jisha_photonic_2025,
title = {Photonic spin-Hall effect in bulk twisted anisotropic media},
author = {Chandroth P. Jisha and Lorenzo Marrucci and Stefan Nolte and Alessandro Alberucci},
url = {https://ieeexplore.ieee.org/abstract/document/11110310/},
year = {2025},
date = {2025-01-01},
urldate = {2026-09-16},
booktitle = {2025 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)},
pages = {1–1},
publisher = {IEEE},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
2024
Tareq Jaouni; Francesco DI COLANDREA; Lorenzo Amato; Filippo Cardano; Ebrahim Karimi
Process tomography of structured optical gates with convolutional neural networks Journal Article
In: MACHINE LEARNING: SCIENCE AND TECHNOLOGY, vol. 5, no. 4, 2024.
@article{<LineBreak> 11588_993651,
title = {Process tomography of structured optical gates with convolutional neural networks},
author = {Tareq Jaouni and Francesco DI COLANDREA and Lorenzo Amato and Filippo Cardano and Ebrahim Karimi},
doi = {10.1088/2632-2153/ad9ba8},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {MACHINE LEARNING: SCIENCE AND TECHNOLOGY},
volume = {5},
number = {4},
abstract = {Efficient and accurate characterization of an experimental setup is a critical requirement in any physical setting. In the quantum realm, the characterization of an unknown operator is experimentally accomplished via Quantum Process Tomography (QPT). This technique combines the outcomes of different projective measurements to reconstruct the underlying process matrix, typically extracted from maximum-likelihood estimation. Here, we exploit the logical correspondence between optical polarization and two-level quantum systems to retrieve the complex action of structured metasurfaces within a QPT-inspired context. In particular, we investigate a deep-learning approach that allows for fast and accurate reconstructions of space-dependent SU(2) operators by only processing a minimal set of measurements. We train a convolutional neural network based on a scalable U-Net architecture to process entire experimental images in parallel. Synthetic processes are reconstructed with average fidelity above 90%. The performance of our routine is experimentally validated in the case of space-dependent polarization transformations acting on a classical laser beam. Our approach further expands the toolbox of data-driven approaches to QPT and shows promise in the real-time characterization of complex optical gates.},
keywords = {},
pubstate = {published},
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Efficient and accurate characterization of an experimental setup is a critical requirement in any physical setting. In the quantum realm, the characterization of an unknown operator is experimentally accomplished via Quantum Process Tomography (QPT). This technique combines the outcomes of different projective measurements to reconstruct the underlying process matrix, typically extracted from maximum-likelihood estimation. Here, we exploit the logical correspondence between optical polarization and two-level quantum systems to retrieve the complex action of structured metasurfaces within a QPT-inspired context. In particular, we investigate a deep-learning approach that allows for fast and accurate reconstructions of space-dependent SU(2) operators by only processing a minimal set of measurements. We train a convolutional neural network based on a scalable U-Net architecture to process entire experimental images in parallel. Synthetic processes are reconstructed with average fidelity above 90%. The performance of our routine is experimentally validated in the case of space-dependent polarization transformations acting on a classical laser beam. Our approach further expands the toolbox of data-driven approaches to QPT and shows promise in the real-time characterization of complex optical gates.
S. Corona-Aquino; Z. Ibarra-Borja; O. Calderon-Losada; B. Piccirillo; V. Vicuna-Hernandez; T. Moctezuma-Quistian; H. Cruz-Ramirez; D. Lopez-Mago; A. B. U'Ren
Generation of heralded vector-polarized single photons in remotely controlled topological classes Journal Article
In: PHYSICAL REVIEW APPLIED, vol. 21, no. 3, pp. 1–10, 2024.
@article{<LineBreak> 11588_956483,
title = {Generation of heralded vector-polarized single photons in remotely controlled topological classes},
author = {S. Corona-Aquino and Z. Ibarra-Borja and O. Calderon-Losada and B. Piccirillo and V. Vicuna-Hernandez and T. Moctezuma-Quistian and H. Cruz-Ramirez and D. Lopez-Mago and A. B. U'Ren},
url = {https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.21.034030},
doi = {10.1103/PhysRevApplied.21.034030},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {PHYSICAL REVIEW APPLIED},
volume = {21},
number = {3},
pages = {1–10},
abstract = {We demonstrate an experimental protocol for the preparation and control of heralded single photons in inhomogeneously polarized states, such as vector vortex and full Poincaré beam states. A laser beam is shaped by a voltage-controlled spin-to-orbital angular momentum converter q-plate device, which elimi- nates the need for an interferometer for the robust preparation of high-quality inhomogeneously polarized beams. Such a beam is then used as a pump in a spontaneous parametric down-conversion (SPDC) photon- pair source. We demonstrate the full pump to heralded single-photon transfer of the intensity and phase distributions, as well as of the vector polarization structure. Additionally, we show that by controlling the polarization to which the heralding idler photon is projected before detection, we can toggle between the direct and basis-switched pump-single-photon transfer. We show that this nonlocal control of the heralded single photon pertains also to the topological class of the resulting heralded single photon. We believe that our work will lead to opportunities in photon-based quantum information processing science.},
keywords = {},
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We demonstrate an experimental protocol for the preparation and control of heralded single photons in inhomogeneously polarized states, such as vector vortex and full Poincaré beam states. A laser beam is shaped by a voltage-controlled spin-to-orbital angular momentum converter q-plate device, which elimi- nates the need for an interferometer for the robust preparation of high-quality inhomogeneously polarized beams. Such a beam is then used as a pump in a spontaneous parametric down-conversion (SPDC) photon- pair source. We demonstrate the full pump to heralded single-photon transfer of the intensity and phase distributions, as well as of the vector polarization structure. Additionally, we show that by controlling the polarization to which the heralding idler photon is projected before detection, we can toggle between the direct and basis-switched pump-single-photon transfer. We show that this nonlocal control of the heralded single photon pertains also to the topological class of the resulting heralded single photon. We believe that our work will lead to opportunities in photon-based quantum information processing science.
Ruqyyah Mushtaq; Shazia Bashir; Khaliq Mehmood; Andrea Rubano
Laser Induced Plasma of Titanium (Ti) as a Source of Thin Film Deposition on Mg-alloy used in Biomedical Implants Journal Article
In: NOVEL JOURNAL OF APPLIED SCIENCES RESEARCH, vol. 1, no. 4, pp. 01–05, 2024.
@article{<LineBreak> 11588_989022,
title = {Laser Induced Plasma of Titanium (Ti) as a Source of Thin Film Deposition on Mg-alloy used in Biomedical Implants},
author = {Ruqyyah Mushtaq and Shazia Bashir and Khaliq Mehmood and Andrea Rubano},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {NOVEL JOURNAL OF APPLIED SCIENCES RESEARCH},
volume = {1},
number = {4},
pages = {01–05},
keywords = {},
pubstate = {published},
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N. Dehghan; A. D'Errico; F. Di Colandrea; E. Karimi
Biphoton state reconstruction via phase retrieval methods Journal Article
In: OPTICA, vol. 11, no. 8, pp. 1115–1123, 2024.
@article{<LineBreak> 11588_989497,
title = {Biphoton state reconstruction via phase retrieval methods},
author = {N. Dehghan and A. D'Errico and F. Di Colandrea and E. Karimi},
doi = {10.1364/OPTICA.527661},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {OPTICA},
volume = {11},
number = {8},
pages = {1115–1123},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
F. Di Colandrea; N. Dehghan; A. D'Errico; E. Karimi
Fourier Quantum Process Tomography Journal Article
In: NPJ QUANTUM INFORMATION, vol. 10, no. 1, 2024.
@article{<LineBreak> 11588_989495,
title = {Fourier Quantum Process Tomography},
author = {F. Di Colandrea and N. Dehghan and A. D'Errico and E. Karimi},
doi = {10.1038/s41534-024-00844-7},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {NPJ QUANTUM INFORMATION},
volume = {10},
number = {1},
keywords = {},
pubstate = {published},
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A. Sit; F. Di Colandrea; A. D'Errico; E. Karimi
Genetic algorithm for the response of arbitrarily twisted nematic liquid crystals to an applied field Journal Article
In: PHYSICAL REVIEW. E, vol. 109, no. 5, 2024.
@article{<LineBreak> 11588_989494,
title = {Genetic algorithm for the response of arbitrarily twisted nematic liquid crystals to an applied field},
author = {A. Sit and F. Di Colandrea and A. D'Errico and E. Karimi},
doi = {10.1103/PhysRevE.109.054705},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {PHYSICAL REVIEW. E},
volume = {109},
number = {5},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
F. Di Colandrea; A. D'Errico; E. Karimi
Recent advances in spin-orbit photonic technologies Proceedings Article
In: Liquid Crystals Optics and Photonic Devices, 2024.
@inproceedings{<LineBreak> 11588_989496,
title = {Recent advances in spin-orbit photonic technologies},
author = {F. Di Colandrea and A. D'Errico and E. Karimi},
doi = {10.1117/12.3028569},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
booktitle = {Liquid Crystals Optics and Photonic Devices},
volume = {13016},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
A. Sit; F. Di Colandrea; A. D'Errico; E. Karimi
Spatially twisted liquid-crystal devices Journal Article
In: APL PHOTONICS, vol. 9, no. 5, 2024.
@article{<LineBreak> 11588_989492,
title = {Spatially twisted liquid-crystal devices},
author = {A. Sit and F. Di Colandrea and A. D'Errico and E. Karimi},
doi = {10.1063/5.0191411},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {APL PHOTONICS},
volume = {9},
number = {5},
keywords = {},
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Federico Belliardo; Valeria Cimini; Emanuele Polino; Francesco Hoch; Bruno Piccirillo; Nicolò Spagnolo; Vittorio Giovannetti; Fabio Sciarrino
Optimizing quantum-enhanced Bayesian multiparameter estimation of phase and noise in practical sensors Journal Article
In: PHYSICAL REVIEW RESEARCH, vol. 6, no. 2, pp. 1–10, 2024.
@article{<LineBreak> 11588_961496,
title = {Optimizing quantum-enhanced Bayesian multiparameter estimation of phase and noise in practical sensors},
author = {Federico Belliardo and Valeria Cimini and Emanuele Polino and Francesco Hoch and Bruno Piccirillo and Nicolò Spagnolo and Vittorio Giovannetti and Fabio Sciarrino},
doi = {10.1103/physrevresearch.6.023201},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {PHYSICAL REVIEW RESEARCH},
volume = {6},
number = {2},
pages = {1–10},
abstract = {Achieving quantum-enhanced performances when measuring unknown quantities requires developing suitable methodologies for practical scenarios, which include noise and the availability of a limited amount of resources. Here, we report on the optimization of substandard quantum limit Bayesian multiparameter estimation in a scenario where a subset of the parameters describes unavoidable noise processes in an experimental photonic sensor. We explore how the optimization of the estimation changes depending on which parameters are either of interest or are treated as nuisance ones. Our results show that optimizing the multiparameter approach in noisy apparata represents a significant tool to fully exploit the potential of practical sensors operating beyond the standard quantum limit for broad resources range.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Achieving quantum-enhanced performances when measuring unknown quantities requires developing suitable methodologies for practical scenarios, which include noise and the availability of a limited amount of resources. Here, we report on the optimization of substandard quantum limit Bayesian multiparameter estimation in a scenario where a subset of the parameters describes unavoidable noise processes in an experimental photonic sensor. We explore how the optimization of the estimation changes depending on which parameters are either of interest or are treated as nuisance ones. Our results show that optimizing the multiparameter approach in noisy apparata represents a significant tool to fully exploit the potential of practical sensors operating beyond the standard quantum limit for broad resources range.
Domenico Paparo; Anna Martinez; Andrea Rubano; Jonathan Houard; Ammar Hideur; Angela Vella
THz Generation by Two-Color Plasma: Time Shaping and Ultra-Broadband Polarimetry Journal Article
In: SENSORS, vol. 24, no. 13, 2024.
@article{<LineBreak> 11588_981057,
title = {THz Generation by Two-Color Plasma: Time Shaping and Ultra-Broadband Polarimetry},
author = {Domenico Paparo and Anna Martinez and Andrea Rubano and Jonathan Houard and Ammar Hideur and Angela Vella},
doi = {10.3390/s24134265},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {SENSORS},
volume = {24},
number = {13},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Gabriella Maria De Luca; Andrea Rubano
Two-Dimensional Ferroelectrics: A Review on Applications and Devices Journal Article
In: SOLIDS, vol. 5, no. 1, pp. 45–65, 2024.
@article{<LineBreak> 11588_981055,
title = {Two-Dimensional Ferroelectrics: A Review on Applications and Devices},
author = {Gabriella Maria De Luca and Andrea Rubano},
doi = {10.3390/solids5010004},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {SOLIDS},
volume = {5},
number = {1},
pages = {45–65},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A. Pecoraro; F. Cardano; L. Marrucci; A. Porzio
Reconfigurable homodyne detector for vortex beams Journal Article
In: PHYSICS LETTERS A, vol. 500, 2024.
@article{<LineBreak> 11588_959567,
title = {Reconfigurable homodyne detector for vortex beams},
author = {A. Pecoraro and F. Cardano and L. Marrucci and A. Porzio},
url = {https://www.slam.unina.it/wp-content/uploads/2025/06/physlettA24.pdf},
doi = {10.1016/j.physleta.2024.129363},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {PHYSICS LETTERS A},
volume = {500},
abstract = {We review the general properties of balanced optical homodyne detectors (BHD) that provide a physical implementation of the quantum field quadrature observable. Then, we discuss the particular case of a BHD designed to span a prescribed sub-space of vortex optical modes carrying orbital angular momentum. By properly tailoring the geometrical features of the local oscillator, mode matching with the signal to be detected is achieved guaranteeing a visibility around 97%. This performance has recently allowed the detection of continuous-variable entanglement between structured modes. Homodyning structured light may pave the way to its use in optical coherent communication and quantum communication protocols.},
keywords = {},
pubstate = {published},
tppubtype = {article}
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We review the general properties of balanced optical homodyne detectors (BHD) that provide a physical implementation of the quantum field quadrature observable. Then, we discuss the particular case of a BHD designed to span a prescribed sub-space of vortex optical modes carrying orbital angular momentum. By properly tailoring the geometrical features of the local oscillator, mode matching with the signal to be detected is achieved guaranteeing a visibility around 97%. This performance has recently allowed the detection of continuous-variable entanglement between structured modes. Homodyning structured light may pave the way to its use in optical coherent communication and quantum communication protocols.
Francesco Di Colandrea; Amin Babazadeh; Alexandre Dauphin; Pietro Massignan; Lorenzo Marrucci; Filippo Cardano
Spin-orbit photonic circuits for quantum simulations Proceedings Article
In: PROCEEDINGS OF SPIE 12911, Quantum Computing, Communication, and Simulation IV, 129110Q (13 March 2024), 2024.
@inproceedings{11588_959568,
title = {Spin-orbit photonic circuits for quantum simulations},
author = {Francesco Di Colandrea and Amin Babazadeh and Alexandre Dauphin and Pietro Massignan and Lorenzo Marrucci and Filippo Cardano},
doi = {10.1117/12.2691444},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
booktitle = {PROCEEDINGS OF SPIE 12911, Quantum Computing, Communication, and Simulation IV, 129110Q (13 March 2024)},
abstract = {The observation of extreme dynamics within quantum simulators based on photonic circuits is typically precluded by optical losses, exponentially increasing with the system depth or, equivalently, with the number of optical components. This is a natural consequence of the standard approach to photonic simulations of quantum dynamics, where the complexity of the setup grows with the extension of the evolution in time. By focusing on simple protocols of discrete-time quantum walks, we show that it is possible to compress homogeneous evolutions within only three liquid-crystal metasurfaces, encompassing up to a few hundreds of time steps. By exploiting spin-orbit effects, these devices implement space-dependent polarization transformations that mix circularly polarized optical modes carrying quantized transverse momentum, mimicking the target quantum dynamics with high efficiency and accuracy. Being extremely versatile, our compact platform will pave the way to the simulations of extreme regimes of more exotic dynamics.},
keywords = {},
pubstate = {published},
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The observation of extreme dynamics within quantum simulators based on photonic circuits is typically precluded by optical losses, exponentially increasing with the system depth or, equivalently, with the number of optical components. This is a natural consequence of the standard approach to photonic simulations of quantum dynamics, where the complexity of the setup grows with the extension of the evolution in time. By focusing on simple protocols of discrete-time quantum walks, we show that it is possible to compress homogeneous evolutions within only three liquid-crystal metasurfaces, encompassing up to a few hundreds of time steps. By exploiting spin-orbit effects, these devices implement space-dependent polarization transformations that mix circularly polarized optical modes carrying quantized transverse momentum, mimicking the target quantum dynamics with high efficiency and accuracy. Being extremely versatile, our compact platform will pave the way to the simulations of extreme regimes of more exotic dynamics.
Carlo Schiano; Bereneice Sephton; Roberto Aiello; Francesco Graffitti; Nijil Lal; Andrea Chiuri; Simone Santoro; Luigi Santamaria Amato; Lorenzo Marrucci; Corrado Lisio; Vincenzo D'Ambrosio
Engineering quantum states from a spatially structured quantum eraser Journal Article
In: SCIENCE ADVANCES, vol. 10, no. 30, 2024.
@article{<LineBreak> 11588_978688,
title = {Engineering quantum states from a spatially structured quantum eraser},
author = {Carlo Schiano and Bereneice Sephton and Roberto Aiello and Francesco Graffitti and Nijil Lal and Andrea Chiuri and Simone Santoro and Luigi Santamaria Amato and Lorenzo Marrucci and Corrado Lisio and Vincenzo D'Ambrosio},
doi = {10.1126/sciadv.adm9278},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {SCIENCE ADVANCES},
volume = {10},
number = {30},
abstract = {Quantum interference is a central resource in many quantum-enhanced tasks, from computation to communication. While usually occurring between identical photons, it can also be enabled by performing projective measurements that render the photons indistinguishable, a process known as quantum erasing. Structured light forms another hallmark of photonics, achieved by manipulating the degrees of freedom of light, and enables a multitude of applications in both classical and quantum regimes. By combining these ideas, we design and experimentally demonstrate a simple and robust scheme that tailors quantum interference to engineer photonic states with spatially structured coalescence along the transverse profile, a type of quantum mode with no classical counterpart. To achieve this, we locally tune the distinguishability of a photon pair by spatially structuring the polarization and creating a structured quantum eraser. We believe that these spatially engineered multiphoton quantum states may be of significance in fields such as quantum metrology, microscopy, and communication.},
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Quantum interference is a central resource in many quantum-enhanced tasks, from computation to communication. While usually occurring between identical photons, it can also be enabled by performing projective measurements that render the photons indistinguishable, a process known as quantum erasing. Structured light forms another hallmark of photonics, achieved by manipulating the degrees of freedom of light, and enables a multitude of applications in both classical and quantum regimes. By combining these ideas, we design and experimentally demonstrate a simple and robust scheme that tailors quantum interference to engineer photonic states with spatially structured coalescence along the transverse profile, a type of quantum mode with no classical counterpart. To achieve this, we locally tune the distinguishability of a photon pair by spatially structuring the polarization and creating a structured quantum eraser. We believe that these spatially engineered multiphoton quantum states may be of significance in fields such as quantum metrology, microscopy, and communication.
Francesco Di Colandrea; Nazanin Dehghan; Filippo Cardano; Alessio D'Errico; Ebrahim Karimi
Manifestation of the quantum metric in chiral lattice systems Journal Article
In: COMMUNICATIONS PHYSICS, vol. 7, no. 1, 2024.
@article{<LineBreak> 11588_969023,
title = {Manifestation of the quantum metric in chiral lattice systems},
author = {Francesco Di Colandrea and Nazanin Dehghan and Filippo Cardano and Alessio D'Errico and Ebrahim Karimi},
doi = {10.1038/s42005-024-01746-y},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {COMMUNICATIONS PHYSICS},
volume = {7},
number = {1},
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2023
F. Di Colandrea; L. Amato; R. Schiattarella; A. Dauphin; F. Cardano
Retrieving space-dependent polarization transformations via near-optimal quantum process tomography Journal Article
In: OPTICS EXPRESS, vol. 31, no. 20, pp. 31698–31717, 2023.
@article{<LineBreak> 11588_1018315,
title = {Retrieving space-dependent polarization transformations via near-optimal quantum process tomography},
author = {F. Di Colandrea and L. Amato and R. Schiattarella and A. Dauphin and F. Cardano},
url = {https://opg.optica.org/oe/fulltext.cfm?uri=oe-31-20-31698},
doi = {10.1364/OE.491518},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {OPTICS EXPRESS},
volume = {31},
number = {20},
pages = {31698–31717},
abstract = {An optical waveplate rotating light polarization can be modeled as a single-qubit unitary operator. This analogy can be exploited to experimentally retrieve a polarization transformation within the paradigm of quantum process tomography. Standard approaches to tomographic problems rely on the maximum-likelihood estimation, providing the most likely transformation to yield the same outcomes as a set of experimental projective measurements. The performances of this method strongly depend on the number of input measurements and the numerical minimization routine that is adopted. Here we investigate the application of genetic and machine learning approaches to this problem, finding that both allow for accurate reconstructions and fast operations when processing a set of projective measurements very close to the minimal one. We apply these techniques to the case of space-dependent polarization transformations, providing an experimental characterization of the optical action of spin-orbit metasurfaces having patterned birefringence. Our efforts thus expand the toolbox of methodologies for optical process tomography. In particular, we find that the neural network-based scheme provides a significant speed-up, that may be critical in applications requiring a characterization in real-time. We expect these results to lay the groundwork for the optimization of tomographic approaches in more general quantum processes, including non-unitary gates and operations in higher-dimensional Hilbert spaces.},
keywords = {},
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An optical waveplate rotating light polarization can be modeled as a single-qubit unitary operator. This analogy can be exploited to experimentally retrieve a polarization transformation within the paradigm of quantum process tomography. Standard approaches to tomographic problems rely on the maximum-likelihood estimation, providing the most likely transformation to yield the same outcomes as a set of experimental projective measurements. The performances of this method strongly depend on the number of input measurements and the numerical minimization routine that is adopted. Here we investigate the application of genetic and machine learning approaches to this problem, finding that both allow for accurate reconstructions and fast operations when processing a set of projective measurements very close to the minimal one. We apply these techniques to the case of space-dependent polarization transformations, providing an experimental characterization of the optical action of spin-orbit metasurfaces having patterned birefringence. Our efforts thus expand the toolbox of methodologies for optical process tomography. In particular, we find that the neural network-based scheme provides a significant speed-up, that may be critical in applications requiring a characterization in real-time. We expect these results to lay the groundwork for the optimization of tomographic approaches in more general quantum processes, including non-unitary gates and operations in higher-dimensional Hilbert spaces.
Chandroth P. Jisha; Stree Vithya Arumugam; Lorenzo Marrucci; Stefan Nolte; Alessandro Alberucci
Waveguiding driven by the Pancharatnam-Berry phase Journal Article
In: PHYSICAL REVIEW A, vol. 107, no. 1, 2023.
@article{<LineBreak> 11588_943870,
title = {Waveguiding driven by the Pancharatnam-Berry phase},
author = {Chandroth P. Jisha and Stree Vithya Arumugam and Lorenzo Marrucci and Stefan Nolte and Alessandro Alberucci},
url = {https://www.slam.unina.it/wp-content/uploads/2025/06/pra23.pdf},
doi = {10.1103/physreva.107.013523},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {PHYSICAL REVIEW A},
volume = {107},
number = {1},
abstract = {We theoretically and numerically investigate the properties of waveguides based on the Pancharatnam-Berry phase, obtained by a longitudinally periodic rotation of the optic axis in a transversely twisted birefringent medium. In this paper we study the case where the period of the longitudinal modulation is chosen so that a net accumulation of geometric phase in propagation occurs. First, the interplay between different contributions to the optical potential is addressed. Second, a continuous evolution of the polarization structure of the quasimodes is observed in the numerical simulations. We explain it by a combination of plane-wave-based models and gauge transformations. We discover that, beyond the longitudinal oscillations, the polarization of the quasimode also varies through its cross section. The analogies with respect to charged particles moving in a magnetic field are outlined.},
keywords = {},
pubstate = {published},
tppubtype = {article}
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We theoretically and numerically investigate the properties of waveguides based on the Pancharatnam-Berry phase, obtained by a longitudinally periodic rotation of the optic axis in a transversely twisted birefringent medium. In this paper we study the case where the period of the longitudinal modulation is chosen so that a net accumulation of geometric phase in propagation occurs. First, the interplay between different contributions to the optical potential is addressed. Second, a continuous evolution of the polarization structure of the quasimodes is observed in the numerical simulations. We explain it by a combination of plane-wave-based models and gauge transformations. We discover that, beyond the longitudinal oscillations, the polarization of the quasimode also varies through its cross section. The analogies with respect to charged particles moving in a magnetic field are outlined.
Hu Jinbing; Carmine Antonio Perroni; Giulio De Filippis; Songlin Zhuang; Lorenzo Marrucci; Filippo Cardano
Electric polarization and its quantization in one-dimensional non-Hermitian chains Journal Article
In: PHYSICAL REVIEW. B, vol. 107, no. 12, 2023.
@article{11588_916341,
title = {Electric polarization and its quantization in one-dimensional non-Hermitian chains},
author = {Hu Jinbing and Carmine Antonio Perroni and Giulio De Filippis and Songlin Zhuang and Lorenzo Marrucci and Filippo Cardano},
url = {https://www.slam.unina.it/wp-content/uploads/2025/06/prb23.pdf},
doi = {10.1103/PhysRevB.107.L121101},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {PHYSICAL REVIEW. B},
volume = {107},
number = {12},
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Chiara Esposito; Francesco Di Colandrea; Francesco Hoch; Gonzalo Carvacho; Filippo Cardano; Nicolò Spagnolo; Lorenzo Marrucci; Fabio Sciarrino
Generation of high-dimensional qudit quantum states via two-dimensional quantum walks Journal Article
In: PHYSICAL REVIEW RESEARCH, vol. 5, no. 4, 2023.
@article{11588_943879,
title = {Generation of high-dimensional qudit quantum states via two-dimensional quantum walks},
author = {Chiara Esposito and Francesco Di Colandrea and Francesco Hoch and Gonzalo Carvacho and Filippo Cardano and Nicolò Spagnolo and Lorenzo Marrucci and Fabio Sciarrino},
doi = {10.1103/PhysRevResearch.5.043025},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {PHYSICAL REVIEW RESEARCH},
volume = {5},
number = {4},
abstract = {Several quantum protocols, with applications ranging from fundamental studies to cryptographic scenarios, can be enhanced through the generation and manipulation of quantum states that belong to high-dimensional Hilbert spaces. For this reason, it is worth devoting efforts to find more efficient methods for complex qudit-state generation. One-dimensional quantum walks have proved to be efficient and versatile platforms for the engineering of such complex states. Hitherto, however, using their two-dimensional counterpart for this task has remained unexplored. In this paper, we consider two-dimensional quantum walk evolution as a tool for the generation of high-dimensional qudit states. We theoretically prove that a suitable change of the coin operators at each step permits the generation of a subset of qudit states by using less resources with respect to the one-dimensional counterpart. Then, we successfully generate qudit states by exploiting two-dimensional quantum walks on an experimental photonic platform. The walker position is encoded on discrete sets of optical modes carrying quantized amounts of transverse momentum and the mode couplings are actively controlled via liquid-crystal devices. The obtained results provide insight into qudit generation for applications in quantum communication and quantum cryptography.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Several quantum protocols, with applications ranging from fundamental studies to cryptographic scenarios, can be enhanced through the generation and manipulation of quantum states that belong to high-dimensional Hilbert spaces. For this reason, it is worth devoting efforts to find more efficient methods for complex qudit-state generation. One-dimensional quantum walks have proved to be efficient and versatile platforms for the engineering of such complex states. Hitherto, however, using their two-dimensional counterpart for this task has remained unexplored. In this paper, we consider two-dimensional quantum walk evolution as a tool for the generation of high-dimensional qudit states. We theoretically prove that a suitable change of the coin operators at each step permits the generation of a subset of qudit states by using less resources with respect to the one-dimensional counterpart. Then, we successfully generate qudit states by exploiting two-dimensional quantum walks on an experimental photonic platform. The walker position is encoded on discrete sets of optical modes carrying quantized amounts of transverse momentum and the mode couplings are actively controlled via liquid-crystal devices. The obtained results provide insight into qudit generation for applications in quantum communication and quantum cryptography.
Francesco Di Colandrea; Amin Babazadeh; Alexandre Dauphin; Pietro Massignan; Lorenzo Marrucci; Filippo Cardano
Ultra-long quantum walks via spin-orbit photonics Journal Article
In: OPTICA, vol. 10, no. 3, 2023.
@article{11588_921728,
title = {Ultra-long quantum walks via spin-orbit photonics},
author = {Francesco Di Colandrea and Amin Babazadeh and Alexandre Dauphin and Pietro Massignan and Lorenzo Marrucci and Filippo Cardano},
doi = {10.1364/optica.474542},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {OPTICA},
volume = {10},
number = {3},
keywords = {},
pubstate = {published},
tppubtype = {article}
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Alessia Suprano; Danilo Zia; Mathias Pont; Taira Giordani; Giovanni Rodari; Mauro Valeri; Bruno Piccirillo; Gonzalo Carvacho; Nicolò Spagnolo; Pascale Senellart; Lorenzo Marrucci; Fabio Sciarrino
Orbital angular momentum based intra- and interparticle entangled states generated via a quantum dot source Journal Article
In: ADVANCED PHOTONICS, vol. 5, no. 04, 2023.
@article{<LineBreak> 11588_943876,
title = {Orbital angular momentum based intra- and interparticle entangled states generated via a quantum dot source},
author = {Alessia Suprano and Danilo Zia and Mathias Pont and Taira Giordani and Giovanni Rodari and Mauro Valeri and Bruno Piccirillo and Gonzalo Carvacho and Nicolò Spagnolo and Pascale Senellart and Lorenzo Marrucci and Fabio Sciarrino},
doi = {10.1117/1.AP.5.4.046008},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {ADVANCED PHOTONICS},
volume = {5},
number = {04},
abstract = {Engineering single-photon states endowed with orbital angular momentum (OAM) is a powerful tool for quantum information photonic implementations. Indeed, due to its unbounded nature, OAM is suitable for encoding qudits, allowing a single carrier to transport a large amount of information. Most of the experimental platforms employ spontaneous parametric down-conversion processes to generate single photons, even if this approach is intrinsically probabilistic, leading to scalability issues for an increasing number of qudits. Semiconductor quantum dots (QDs) have been used to get over these limitations by producing on- demand pure and indistinguishable single-photon states, although only recently they have been exploited to create OAM modes. Our work employs a bright QD single-photon source to generate a complete set of quantum states for information processing with OAM-endowed photons. We first study hybrid intraparticle entanglement between OAM and polarization degrees of freedom of a single photon whose preparation was certified by means of Hong–Ou–Mandel visibility. Then, we investigate hybrid interparticle OAM- based entanglement by exploiting a probabilistic entangling gate. The performance of our approach is assessed by performing quantum state tomography and violating Bell inequalities. Our results pave the way for the use of deterministic sources for the on-demand generation of photonic high-dimensional quantum states.},
keywords = {},
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Engineering single-photon states endowed with orbital angular momentum (OAM) is a powerful tool for quantum information photonic implementations. Indeed, due to its unbounded nature, OAM is suitable for encoding qudits, allowing a single carrier to transport a large amount of information. Most of the experimental platforms employ spontaneous parametric down-conversion processes to generate single photons, even if this approach is intrinsically probabilistic, leading to scalability issues for an increasing number of qudits. Semiconductor quantum dots (QDs) have been used to get over these limitations by producing on- demand pure and indistinguishable single-photon states, although only recently they have been exploited to create OAM modes. Our work employs a bright QD single-photon source to generate a complete set of quantum states for information processing with OAM-endowed photons. We first study hybrid intraparticle entanglement between OAM and polarization degrees of freedom of a single photon whose preparation was certified by means of Hong–Ou–Mandel visibility. Then, we investigate hybrid interparticle OAM- based entanglement by exploiting a probabilistic entangling gate. The performance of our approach is assessed by performing quantum state tomography and violating Bell inequalities. Our results pave the way for the use of deterministic sources for the on-demand generation of photonic high-dimensional quantum states.