Optical orbital angular momentum(OAM)mode multiplexing has emerged as a promising technique for boosting communication capacity.However,most existing studies have concentrated on channel(de)-multiplexing,overlooking t...Optical orbital angular momentum(OAM)mode multiplexing has emerged as a promising technique for boosting communication capacity.However,most existing studies have concentrated on channel(de)-multiplexing,overlooking the critical aspect of channel routing.This challenge involves the reallocation of multiplexed OAM modes across both spatial and temporal domains—a vital step for developing versatile communication networks.To address this gap,we introduce a novel approach based on the time evolution of OAM modes,utilizing the orthogonal conversion and diffractive modulation capabilities of unitary transformations.This approach facilitates high-dimensional orthogonal transformations of OAM mode vectors,altering both the propagation direction and the spatial location.Using Fresnel diffraction matrices as unitary operators,it manipulates the spatial locations of light beams during transmission,breaking the propagation invariance and enabling temporal evolution.As a demonstration,we have experimentally implemented the deep routing of four OAM modes within two distinct time sequences.Achieving an average diffraction efficiency above 78.31%,we have successfully deep-routed 4.69 Tbit-s^(-1)quadrature phase-shift keying(QPSK)signals carried by four multiplexed OAM channels,with a bit error rate below 10^(-6).These results underscore the efficacy of our routing strategy and its promising prospects for practical applications.展开更多
Advancements in orbital angular momentum (OAM) mode-multiplexing communication networks requiretunable mode filters for selective channel demultiplexing and downloading. In this study, we propose a spatialdepth-depend...Advancements in orbital angular momentum (OAM) mode-multiplexing communication networks requiretunable mode filters for selective channel demultiplexing and downloading. In this study, we propose a spatialdepth-dependent mode transformation strategy for the tunable filtering of OAM modes. By integrating the spiralphase and lens phase modulations, we achieved mode conversions that varied with the transmission depth,enabling selective demultiplexing in predetermined axial planes. This approach facilitates tunable mode filteringby adjusting spatial depths. As a proof of concept, we fabricated a mode filter using two-photon polymerizationlithography (TPL) technology, successfully filtering five OAM modes with mode crosstalk below −10.9 dB.Additionally, the filter was applied in a mode-multiplexing communication link, achieving tunable demultiplexingof five mode channels with bit error rates below 10^(−6). These results highlight the efficacy and flexibilityof our strategy for OAM mode filtering and offer promising insights for the development of mode-multiplexingcommunication networks and channel interconnections.展开更多
Cylindrical vector beams(CVBs)hold significant promise in mode division multiplexing communication owing to their inherent vector mode orthogonality.However,existing studies for facilitating CVB channel processing are...Cylindrical vector beams(CVBs)hold significant promise in mode division multiplexing communication owing to their inherent vector mode orthogonality.However,existing studies for facilitating CVB channel processing are confined to mode shift conversions due to their reliance on spin-dependent helical modulations,overlooking the pursuit of mode multiplication conversion.This challenge lies in the multiplicative operation upon inhomogeneous vector mode manipulation,which is expected to advance versatile CVB channel switching and routing.Here,we tackle this gap by introducing a raytracing control strategy that conformally maps the light rays of CVB from the whole annulus distribution to an annular sector counterpart.Incorporated with the multifold conformal annulus-sector mappings and polarization-insensitive phase modulations,this approach facilitates the parallel transformation of input CVB into multiple complementary components,enabling the mode multiplication conversion with protected vector structure.Serving as a demonstration,we experimentally implemented the multiplicative operation of four CVB modes with the multiplier factors of N=+2 and N=−3,achieving the converted mode purities over 94.24%and 88.37%.Subsequently,200 Gbit/s quadrature phase shift keying signals were successfully transmitted upon multiplicative switching of four CVB channels,with the bit-error-rate approaching 1×10^(−6).These results underscore our strategy’s efficacy in CVB mode multiplication,which may open promising prospects for its advanced applications.展开更多
The emergence of cascaded metasurface holography has opened up a promising avenue for realizing high-capacity optical data storage and security information encryption.However,in the majority of existing cascaded confi...The emergence of cascaded metasurface holography has opened up a promising avenue for realizing high-capacity optical data storage and security information encryption.However,in the majority of existing cascaded configurations,the inherent cascade-phase overlap prevents the retrieval of additional holographic information from each single-layer metasurface unless these metasurfaces are physically separated.To overcome this limitation,we propose a controllable cascade-phase modulation solution for enabling flexible switching between single-layer and cascaded holograms that utilizes helicitydecoupled Ge_(2)Sb_(2)Te_(5)(GST)metasurfaces.By harnessing the prominent optical-phase response contrast in GST transition,we show that phase-type holographic profiles tailored using GST nanopillars can be arbitrarily retrieved in their amorphous state while completely hidden in the crystalline state;this allows the active separation and combination of bilayer phases through controlling the amorphous-crystalline state transition of GST.Additionally,combined with the helicity-decoupled phase modulation mechanism,the optical dual-helicity channels offer polarization control operation for cascade-phase function switching.As a proof-of-concept,the designed GST metasurfaces are used to successfully reconstruct four single-layer and two cascaded holographic images separately through a synergistic control of the GST transition and by leveraging the helicity of the incident light.This feature also results in a reliable holographic encryption strategy for transmitting ciphered information.The proposed technology not only overcomes the physical constraints of multilayer phase overlap but is also compatible with existing cascade-related holographic multiplexing methodologies,which may promote the advanced explorations of optical multilevel modulation,multidimensional displays,and high-density optical storage.展开更多
Photonic moirélattices(PMLs),with unique twisted periodic patterns,provide a valuable platform for investigating strongly correlated materials,unconventional superconductivity,and the localization–delocalization...Photonic moirélattices(PMLs),with unique twisted periodic patterns,provide a valuable platform for investigating strongly correlated materials,unconventional superconductivity,and the localization–delocalization transition.However,PMLs created either by the misorientation between lattice layers or by twisted van der Waals materials are typically non-tunable and inherently possess immutable refractive indices.Unlike those in the moirélattices of twisted two-dimensional materials,our work reports a moirélattice formed by overlapping two identical sublattices with twisted angles in an ultracold atomic ensemble.This photoinduced moirélattice with two twisted sublattices exhibits high flexibility and rich periodicity through adjustable twisted angles.Our results indicate that both the absorption/dispersion coefficients and the transmission of the photoinduced moirélattices can be effectively tuned by photon detuning and Rabi frequency,resulting in amplitude-and phase-type moirélattices.Based on the Fraunhofer diffraction theory,we have demonstrated that the far-field diffraction efficiency can be adjusted via altering photon detuning,and the rotation angle serves as a control knob for modulating the diffracted intensity distribution,thereby optimizing the performance of the photonic lattice.It is also found that the operation domains of the moirélattices with different rotation angles remain consistent,allowing for seamless conversion between various moiréperiod structures.Furthermore,a moirélattice composed of three twisted sublattices is investigated,revealing that the diffraction energy is uniformly dispersed in a circular distribution,which provides excellent agility in the design of optical devices.Such tunable PML offer a powerful tool for studying light propagation control and the intriguing physics of twisted systems in atomic media.展开更多
On-chip multidimensional multiplexing has shown considerable potential for enhancing transmission capacity and developing communication networks in integrated optical systems.Micro-ring resonators,which utilize the wa...On-chip multidimensional multiplexing has shown considerable potential for enhancing transmission capacity and developing communication networks in integrated optical systems.Micro-ring resonators,which utilize the wavelength-dependent whispering gallery resonance mechanism and feature customizable cavity lengths,offer inherent advantages for accurate wavelength filtering.These characteristics make them promising candidates for wavelength multiplexers.However,a significant challenge arises from the mismatch in the effective refractive index between orthogonal linear polarizations,which introduces complexities to polarization channel multiplexing and impedes progress in on-chip multidimensional multiplexing that integrates both wavelength and polarization channels.In this work,we propose a double-layer adiabatic structureconnected micro-ring resonator(AMRR)with vertical refractive index asymmetry,demonstrating its utility in multidimensional(de)multiplexers.Our approach enables polarization division multiplexing(PDM)by facilitating polarization rotation between transverse electric and transverse magnetic polarizations through polarization hybridization.The(de)multiplexing of both wavelength and polarization channels is achieved by controlling the incident light direction and filtering the resonance wavelength within the micro-ring resonator.As a proof of concept,we successfully transmitted 144 Gbit/s QPSK-OFDM signals and achieved bit error rates below the forward error correction threshold at-19 d Bm using the proposed multidimensional(de)multiplexer,which accommodates 3 wavelengths and 2 polarizations.Our design,which leverages the AMRR for simultaneous(de)multiplexing of wavelength and polarization channels,not only overcomes the limitation of traditional micro-ring resonators in implementing PDM,but also reduces the footprint of the multidimensional(de)multiplexer to 27μm×219μm,an order of magnitude smaller compared to conventional designs.展开更多
Orbital angular momentum(OAM)modes provide an additional orthogonal physical dimension,offering transformative potential for enhancing optical communication capacity.Despite significant progress in mode multiplexing,t...Orbital angular momentum(OAM)modes provide an additional orthogonal physical dimension,offering transformative potential for enhancing optical communication capacity.Despite significant progress in mode multiplexing,the development of robust communication networks faces persistent challenges,particularly in effectively routing and controlling these multiplexed channels among network nodes.To tackle these dilemmas,we propose a rotatable diffractive neural network(R-DNN)strategy and demonstrate its capability for port-controllable OAM mode routing.By leveraging the correlation between the orthogonal evolution of OAM modes in free space and phase modulations during propagation,the R-DNN precisely shapes the spatial evolution of mode fields through multiple rotatable phase layers,enabling efficient routing to specific output ports.This approach exploits the interaction of secondary wavelets with the relative states of the rotatable layers,allowing on-demand control of mode evolution paths and enhancing routing flexibility.As a proof of concept,we developed a tri-functional router that successfully directs three OAM modes to individually controllable output ports.This router achieves an average intermode crosstalk of less than−16.4 dB across three functional states,one-dimensional,two-dimensional,and cross-connected switching,while supporting the routing of 5.85 Tbit/s quadrature phase-shift keying signals.These results highlight the R-DNN’s effectiveness in achieving precise and controllable OAM mode manipulation,paving the way for advanced applications in mode-multiplexed communication networks and beyond.展开更多
The progress of on-chip optical communication relies on integrated multi-dimensional mode(de)multiplexers to enhance communication capacity and establish comprehensive networks.However,existing multi-dimensional(de)mu...The progress of on-chip optical communication relies on integrated multi-dimensional mode(de)multiplexers to enhance communication capacity and establish comprehensive networks.However,existing multi-dimensional(de)multiplexers,involving modes and wavelengths,face limitations due to their reliance on single-directional total internal reflection and multi-level mode conversion based on directional coupling principles.These constraints restrict their potential for full-duplex functionality and highly integrated communication.We solve these problems by introducing a photonic-like crystal-connected bidirectional micro-ring resonator array(PBMRA)and apply it to duplex mode-wavelength multiplexing communication.The directional independence of total internal reflection and the cumulative effect of the subwavelength-scale pillar within the single-level photonic crystal enable bidirectional mode and wavelength multiplexed signals to transmit among multi-pair nodes without interference,improving on-chip integration in single-level mode conversion.As a proof of concept,we fabricated a nine-channel bidirectional multi-dimensional(de)multiplexer,featuring three wavelengths and three TE modes,compactly housed within a footprint of 80μm×80μm,which efficiently transmits QPSK-OFDM signals at a rate of 216 Gbit/s,achieving a bit error rate lower than 10^(-4).Leveraging the co-ring transmission characteristic and the orthogonality of the mode-wavelength channel,this(de)multiplexer also enables a doubling of communication capacity using two physical transmission channels.展开更多
The advancement of integrated optical communication networks necessitates the deployment of on-chip beam splitters for efficient signal interconnections at network nodes.However,the pursuit of micron-scale beam splitt...The advancement of integrated optical communication networks necessitates the deployment of on-chip beam splitters for efficient signal interconnections at network nodes.However,the pursuit of micron-scale beam splitting with large corners and reducing the device footprint to boost connection flexibility often results in phase mismatches.These mismatches,which stem from radiation modes and backward scattering,pose significant obstacles in creating highly integrated and interference-resistant connections.To address this,we introduce a solution based on the topological valley-contrasting state generated by photonic crystals with opposing valley Chern numbers,manifested in a harpoon-shaped structure designed to steer the splitting channels.This approach enables adiabatic mode field evolution over large corners,capitalizing on the robust phase modulation capabilities and topological protection provided by the subwavelength-scale valley-contrasting state.Our demonstration reveals that beam splitters with large corners of 60°,90°,and 120°exhibit insertion loss fluctuations below 2.7 dB while maintaining a minimal footprint of 8.8μm×8.8μm.As a practical demonstration,these devices facilitate three-channel signal connections,successfully transmitting quadrature phase shift keying signals at 3.66 Tbit/s with bit error rates below the forward error correction threshold,demonstrating performance comparable to that in defects scenarios.By harnessing the unidirectional excitation feature,we anticipate significant enhancements in the capabilities of signal distribution and connection networks through a daisy chain configuration.展开更多
Liquid crystal(LC)photonic devices have attracted intensive attention in recent decades,due to the merits of tunability,cost-effectiveness,and high efficiency.However,the precise and efficient simulation of large-scal...Liquid crystal(LC)photonic devices have attracted intensive attention in recent decades,due to the merits of tunability,cost-effectiveness,and high efficiency.However,the precise and efficient simulation of large-scale three-dimensional electrically stimulated LC photonic devices remains challenging and resource consuming.Here we report a straightforward nonuniform finite difference method(NFDM)for efficiently simulating largescale LC photonic devices by employing a spatially nonuniform mesh grid.展开更多
The emergence of cylindrical vector beam(CVB)multiplexing has opened new avenues for high-capacity optical communication.Although several configurations have been developed to couple/separate CVBs,the CVB multiplexer/...The emergence of cylindrical vector beam(CVB)multiplexing has opened new avenues for high-capacity optical communication.Although several configurations have been developed to couple/separate CVBs,the CVB multiplexer/demultiplexer remains elusive due to lack of effective off-axis polarization control technologies.Here we report a straightforward approach to realize off-axis polarization control for CVB multiplexing/demultiplexing based on a metal–dielectric–metal metasurface.We show that the left-and right-handed circularly polarized(LHCP/RHCP)components of CVBs are independently modulated via spin-to-orbit interactions by the properly designed metasurface,and then simultaneously multiplexed and demultiplexed due to the reversibility of light path and the conservation of vector mode.We also show that the proposed multiplexers/demultiplexers are broadband(from 1310 to 1625 nm)and compatible with wavelength-division-multiplexing.As a proof of concept,we successfully demonstrate a four-channel CVB multiplexing communication,combining wavelength-division-multiplexing and polarization-division-multiplexing with a transmission rate of 1.56 Tbit/s and a bit-error-rate of 10^(−6) at the receive power of−21.6 dBm.This study paves the way for CVB multiplexing/demultiplexing and may benefit high-capacity CVB communication.展开更多
Optical logical operations demonstrate the key role of optical digital computing,which can perform general-purpose calculations and possess fast processing speed,low crosstalk,and high throughput.The logic states usua...Optical logical operations demonstrate the key role of optical digital computing,which can perform general-purpose calculations and possess fast processing speed,low crosstalk,and high throughput.The logic states usually refer to linear momentums that are distinguished by intensity distributions,which blur the discrimination boundary and limit its sustainable applications.Here,we introduce orbital angular momentum(OAM)mode logical operations performed by optical diffractive neural networks(ODNNs).Using the OAM mode as a logic state not only can improve the parallel processing ability but also enhance the logic distinction and robustness of logical gates owing to the mode infinity and orthogonality.ODNN combining scalar diffraction theory and deep learning technology is designed to independently manipulate the mode and spatial position of multiple OAM modes,which allows for complex multilight modulation functions to respond to logic inputs.We show that few-layer ODNNs successfully implement the logical operations of AND,OR,NOT,NAND,and NOR in simulations.The logic units of XNOR and XOR are obtained by cascading the basic logical gates of AND,OR,and NOT,which can further constitute logical half-adder gates.Our demonstrations may provide a new avenue for optical logical operations and are expected to promote the practical application of optical digital computing.展开更多
Microlens arrays(MLAs)based on the selective wetting have opened new avenues for developing compact and miniaturized imaging and display techniques with ultrahigh resolution beyond the traditional bulky and volumetric...Microlens arrays(MLAs)based on the selective wetting have opened new avenues for developing compact and miniaturized imaging and display techniques with ultrahigh resolution beyond the traditional bulky and volumetric optics.However,the selective wetting lenses explored so far have been constrained by the lack of precisely defined pattern for highly controllable wettability contrast,thus limiting the available droplet curvature and numerical aperture,which is a major challenge towards the practical high-performance MLAs.Here we report a mold-free and self-assembly approach of mass-production of scalable MLAs,which can also have ultrasmooth surface,ultrahigh resolution,and the large tuning range of the curvatures.The selective surface modification based on tunable oxygen plasma can facilitate the precise pattern with adjusted chemical contrast,thus creating large-scale microdroplets array with controlled curvature.The numerical aperture of the MLAs can be up to 0.26 and precisely tuned by adjusting the modification intensity or the droplet dose.The fabricated MLAs have high-quality surface with subnanometer roughness and allow for record-high resolution imaging up to equivalently 10,328 ppi,as we demonstrated.This study shows a cost-effective roadmap for mass-production of high-performance MLAs,which may find applications in the rapid proliferating integral imaging industry and high-resolution display.展开更多
Photonic spin Hall efect(SHE)provides new opportunities for achieving spin-based photonics applications.However,flexibly manipulating the spin-dependent sltting(SDS)of photonic SHE and imposing extra phase modulation ...Photonic spin Hall efect(SHE)provides new opportunities for achieving spin-based photonics applications.However,flexibly manipulating the spin-dependent sltting(SDS)of photonic SHE and imposing extra phase modulation on the two spin components are always a challenge.Here,a controllable SHE mechanism based on phase function construction is reported.It is conduded that the phases with specific functional structures performing a coordinate translation are equivalent to integrating a gradient phase to the original phases.Hence,the original phase can be used for independent phase modulation,and the gradient phase originating from the co-ordinate translation is capable of manipulating the SDS.A metasurface with Pancharatnam-Berry phase that can impose conjugate phases to the two spin components of light is fabricated to verify this mechanism.By shifing the light position,the SDS is continuously manipulated in the visible region,which is successfully used for detecting the polarization llipticity.The extra phase modulation is also performed with the original phase and thus enables measuring singular beams.It is anticipated that the controllable SHE manipulation method may open new avenues in the fields of spin photonics,optical sensing,optical communications,etc.展开更多
Metasurfaces composed of spatially arranged ultrathin subwavelength elements are promising photonic devices for manipulating optical wavefronts,with potential applications in holography,metalens,and multiplexing commu...Metasurfaces composed of spatially arranged ultrathin subwavelength elements are promising photonic devices for manipulating optical wavefronts,with potential applications in holography,metalens,and multiplexing communications.Finding microstructures that meet light modulation requirements is always a challenge in designing metasurfaces,where parameter sweep,gradient-based inverse design,and topology optimization are the most commonly used design methods in which the massive electromagnetic iterations require the design computational cost and are sometimes prohibitive.Herein,we propose a fast inverse design method that combines a physicsbased neural network surrogate model(NNSM)with an optimization algorithm.The NNSM,which can generate an accurate electromagnetic response from the geometric topologies of the meta-atoms,is constructed for electromagnetic iterations,and the optimization algorithm is used to search for the on-demand meta-atoms from the phase library established by the NNSM to realize an inverse design.This method addresses two important problems in metasurface design:fast and accurate electromagnetic wave phase prediction and inverse design through a single phase-shift value.As a proof-of-concept,we designed an orbital angular momentum(de)multiplexer based on a phase-type metasurface,and 200 Gbit/s quadrature-phase shift-keying signals were successfully transmitted with a bit error rate approaching 1.67×10^(-6).Because the design is mainly based on an optimization algorithm,it can address the“one-to-many”inverse problem in other micro/nano devices such as integrated photonic circuits,waveguides,and nano-antennas.展开更多
Conventional periodic structures usually have nontunable refractive indices and thus lead to immutable photonic bandgaps. A periodic structure created in an ultracold atoms ensemble by externally controlled light can ...Conventional periodic structures usually have nontunable refractive indices and thus lead to immutable photonic bandgaps. A periodic structure created in an ultracold atoms ensemble by externally controlled light can overcome this disadvantage and enable lots of promising applications. Here, two novel types of optically induced square lattices, i.e., the amplitude and phase lattices, are proposed in an ultracold atoms ensemble by interfering four ordinary plane waves under different parameter conditions. We demonstrate that in the far-field regime, the atomic amplitude lattice with high transmissivity behaves similarly to an ideal pure sinusoidal amplitude lattice, whereas the atomic phase lattices capable of producing phase excursion across a weak probe beam along with high transmissivity remains equally ideal. Moreover, we identify that the quality of Talbot imaging about a phase lattice is greatly improved when compared with an amplitude lattice. Such an atomic lattice could find applications in alloptical switching at the few photons level and paves the way for imaging ultracold atoms or molecules both in the near-field and in the far-field with a nondestructive and lensless approach.展开更多
基金the National Natural Science Foundation of China(62271322)the Guangdong Basic and Applied Basic Research Foundation(2022A1515011003 and 2023A1515030152)the Shenzhen Science and Technology Program(JCYJ20210324095610027 and JCYJ20210324095611030).
文摘Optical orbital angular momentum(OAM)mode multiplexing has emerged as a promising technique for boosting communication capacity.However,most existing studies have concentrated on channel(de)-multiplexing,overlooking the critical aspect of channel routing.This challenge involves the reallocation of multiplexed OAM modes across both spatial and temporal domains—a vital step for developing versatile communication networks.To address this gap,we introduce a novel approach based on the time evolution of OAM modes,utilizing the orthogonal conversion and diffractive modulation capabilities of unitary transformations.This approach facilitates high-dimensional orthogonal transformations of OAM mode vectors,altering both the propagation direction and the spatial location.Using Fresnel diffraction matrices as unitary operators,it manipulates the spatial locations of light beams during transmission,breaking the propagation invariance and enabling temporal evolution.As a demonstration,we have experimentally implemented the deep routing of four OAM modes within two distinct time sequences.Achieving an average diffraction efficiency above 78.31%,we have successfully deep-routed 4.69 Tbit-s^(-1)quadrature phase-shift keying(QPSK)signals carried by four multiplexed OAM channels,with a bit error rate below 10^(-6).These results underscore the efficacy of our routing strategy and its promising prospects for practical applications.
文摘Advancements in orbital angular momentum (OAM) mode-multiplexing communication networks requiretunable mode filters for selective channel demultiplexing and downloading. In this study, we propose a spatialdepth-dependent mode transformation strategy for the tunable filtering of OAM modes. By integrating the spiralphase and lens phase modulations, we achieved mode conversions that varied with the transmission depth,enabling selective demultiplexing in predetermined axial planes. This approach facilitates tunable mode filteringby adjusting spatial depths. As a proof of concept, we fabricated a mode filter using two-photon polymerizationlithography (TPL) technology, successfully filtering five OAM modes with mode crosstalk below −10.9 dB.Additionally, the filter was applied in a mode-multiplexing communication link, achieving tunable demultiplexingof five mode channels with bit error rates below 10^(−6). These results highlight the efficacy and flexibilityof our strategy for OAM mode filtering and offer promising insights for the development of mode-multiplexingcommunication networks and channel interconnections.
基金supported by the National Natural Science Foundation of China(Grant No.62271322)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515030152)+1 种基金the Shenzhen Science and Technology Program(Grant No.JCYJ20210324095610027)the Natural Science Foundation of Top Talent of SZTU(Grant No.GDRC202204)。
文摘Cylindrical vector beams(CVBs)hold significant promise in mode division multiplexing communication owing to their inherent vector mode orthogonality.However,existing studies for facilitating CVB channel processing are confined to mode shift conversions due to their reliance on spin-dependent helical modulations,overlooking the pursuit of mode multiplication conversion.This challenge lies in the multiplicative operation upon inhomogeneous vector mode manipulation,which is expected to advance versatile CVB channel switching and routing.Here,we tackle this gap by introducing a raytracing control strategy that conformally maps the light rays of CVB from the whole annulus distribution to an annular sector counterpart.Incorporated with the multifold conformal annulus-sector mappings and polarization-insensitive phase modulations,this approach facilitates the parallel transformation of input CVB into multiple complementary components,enabling the mode multiplication conversion with protected vector structure.Serving as a demonstration,we experimentally implemented the multiplicative operation of four CVB modes with the multiplier factors of N=+2 and N=−3,achieving the converted mode purities over 94.24%and 88.37%.Subsequently,200 Gbit/s quadrature phase shift keying signals were successfully transmitted upon multiplicative switching of four CVB channels,with the bit-error-rate approaching 1×10^(−6).These results underscore our strategy’s efficacy in CVB mode multiplication,which may open promising prospects for its advanced applications.
基金supported by the National Natural Science Foundation of China(Grant No.62271322)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515030152)+2 种基金the Science and Technology Project of Shenzhen(Grant No.ZDSYS201707271014468)the Shenzhen Science and Technology Program(Grant No.JCYJ20240813143018024)the Natural Science Foundation of Top Talent of SZTU(Grant No.GDRC202204)。
文摘The emergence of cascaded metasurface holography has opened up a promising avenue for realizing high-capacity optical data storage and security information encryption.However,in the majority of existing cascaded configurations,the inherent cascade-phase overlap prevents the retrieval of additional holographic information from each single-layer metasurface unless these metasurfaces are physically separated.To overcome this limitation,we propose a controllable cascade-phase modulation solution for enabling flexible switching between single-layer and cascaded holograms that utilizes helicitydecoupled Ge_(2)Sb_(2)Te_(5)(GST)metasurfaces.By harnessing the prominent optical-phase response contrast in GST transition,we show that phase-type holographic profiles tailored using GST nanopillars can be arbitrarily retrieved in their amorphous state while completely hidden in the crystalline state;this allows the active separation and combination of bilayer phases through controlling the amorphous-crystalline state transition of GST.Additionally,combined with the helicity-decoupled phase modulation mechanism,the optical dual-helicity channels offer polarization control operation for cascade-phase function switching.As a proof-of-concept,the designed GST metasurfaces are used to successfully reconstruct four single-layer and two cascaded holographic images separately through a synergistic control of the GST transition and by leveraging the helicity of the incident light.This feature also results in a reliable holographic encryption strategy for transmitting ciphered information.The proposed technology not only overcomes the physical constraints of multilayer phase overlap but is also compatible with existing cascade-related holographic multiplexing methodologies,which may promote the advanced explorations of optical multilevel modulation,multidimensional displays,and high-density optical storage.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.62074127,U21A2073,62304173,62304175,62404177,61804122,11874142,61627812,61705176,11874102,11474048,and 61805068)the Natural Science Fund of Shaanxi Province(Grant Nos.2018JQ6002,2021JQ062,2021JQ056,and 2021GY223)+4 种基金the Postdoctoral Science Foundation(Grant Nos.2019M653637,2019M660256,and 2017M620300)the National Key Research and Development Program of China(Grant No.2018YFE0125900)the Fundamental Research Funds for the Central Universities(FRFCU)(Grant No.ZYGX2019J102)the National Key R&D Program of China(NK R&D PC)(Grant Nos.2021YFB3602100,2017YFB0402800,and 2017YFB0402802)the Natural Science Basic Research Program of Shaanxi Province(Grant No.2024JC-YBMS-505).
文摘Photonic moirélattices(PMLs),with unique twisted periodic patterns,provide a valuable platform for investigating strongly correlated materials,unconventional superconductivity,and the localization–delocalization transition.However,PMLs created either by the misorientation between lattice layers or by twisted van der Waals materials are typically non-tunable and inherently possess immutable refractive indices.Unlike those in the moirélattices of twisted two-dimensional materials,our work reports a moirélattice formed by overlapping two identical sublattices with twisted angles in an ultracold atomic ensemble.This photoinduced moirélattice with two twisted sublattices exhibits high flexibility and rich periodicity through adjustable twisted angles.Our results indicate that both the absorption/dispersion coefficients and the transmission of the photoinduced moirélattices can be effectively tuned by photon detuning and Rabi frequency,resulting in amplitude-and phase-type moirélattices.Based on the Fraunhofer diffraction theory,we have demonstrated that the far-field diffraction efficiency can be adjusted via altering photon detuning,and the rotation angle serves as a control knob for modulating the diffracted intensity distribution,thereby optimizing the performance of the photonic lattice.It is also found that the operation domains of the moirélattices with different rotation angles remain consistent,allowing for seamless conversion between various moiréperiod structures.Furthermore,a moirélattice composed of three twisted sublattices is investigated,revealing that the diffraction energy is uniformly dispersed in a circular distribution,which provides excellent agility in the design of optical devices.Such tunable PML offer a powerful tool for studying light propagation control and the intriguing physics of twisted systems in atomic media.
基金supported by the National Natural Science Foundation of China(Grant Nos.62271322,62331004,and 62222501)Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515030152)+5 种基金the Science and Technology Project of Shenzhen(Grant No.ZDSYS201707271014468)Shenzhen Science and Technology Program(Grant No.JCYJ20240813143018024)the Natural Science Foundation of Top Talent of SZTU(Grant No.GDRC202204)Qianxinan Prefecture Science and Technology Plan Project(Grant No.2023123)the Scientific Research Fund Project of Minzu Normal University of Xingyi(Grant No.23XYZD07)Guizhou Province Youth Science and Technology Talent Development Project(Qian Jiaoji[2024]No.244)。
文摘On-chip multidimensional multiplexing has shown considerable potential for enhancing transmission capacity and developing communication networks in integrated optical systems.Micro-ring resonators,which utilize the wavelength-dependent whispering gallery resonance mechanism and feature customizable cavity lengths,offer inherent advantages for accurate wavelength filtering.These characteristics make them promising candidates for wavelength multiplexers.However,a significant challenge arises from the mismatch in the effective refractive index between orthogonal linear polarizations,which introduces complexities to polarization channel multiplexing and impedes progress in on-chip multidimensional multiplexing that integrates both wavelength and polarization channels.In this work,we propose a double-layer adiabatic structureconnected micro-ring resonator(AMRR)with vertical refractive index asymmetry,demonstrating its utility in multidimensional(de)multiplexers.Our approach enables polarization division multiplexing(PDM)by facilitating polarization rotation between transverse electric and transverse magnetic polarizations through polarization hybridization.The(de)multiplexing of both wavelength and polarization channels is achieved by controlling the incident light direction and filtering the resonance wavelength within the micro-ring resonator.As a proof of concept,we successfully transmitted 144 Gbit/s QPSK-OFDM signals and achieved bit error rates below the forward error correction threshold at-19 d Bm using the proposed multidimensional(de)multiplexer,which accommodates 3 wavelengths and 2 polarizations.Our design,which leverages the AMRR for simultaneous(de)multiplexing of wavelength and polarization channels,not only overcomes the limitation of traditional micro-ring resonators in implementing PDM,but also reduces the footprint of the multidimensional(de)multiplexer to 27μm×219μm,an order of magnitude smaller compared to conventional designs.
基金supported by the National Natural Science Foundation of China(Grant Nos.62271322,62331004,and 62222501)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515030152)+1 种基金the Science and Technology Project of Shenzhen(Grant No.ZDSYS201707271014468)the Natural Science Foundation of Top Talent of SZTU(Grant No.GDRC202204)。
文摘Orbital angular momentum(OAM)modes provide an additional orthogonal physical dimension,offering transformative potential for enhancing optical communication capacity.Despite significant progress in mode multiplexing,the development of robust communication networks faces persistent challenges,particularly in effectively routing and controlling these multiplexed channels among network nodes.To tackle these dilemmas,we propose a rotatable diffractive neural network(R-DNN)strategy and demonstrate its capability for port-controllable OAM mode routing.By leveraging the correlation between the orthogonal evolution of OAM modes in free space and phase modulations during propagation,the R-DNN precisely shapes the spatial evolution of mode fields through multiple rotatable phase layers,enabling efficient routing to specific output ports.This approach exploits the interaction of secondary wavelets with the relative states of the rotatable layers,allowing on-demand control of mode evolution paths and enhancing routing flexibility.As a proof of concept,we developed a tri-functional router that successfully directs three OAM modes to individually controllable output ports.This router achieves an average intermode crosstalk of less than−16.4 dB across three functional states,one-dimensional,two-dimensional,and cross-connected switching,while supporting the routing of 5.85 Tbit/s quadrature phase-shift keying signals.These results highlight the R-DNN’s effectiveness in achieving precise and controllable OAM mode manipulation,paving the way for advanced applications in mode-multiplexed communication networks and beyond.
基金Natural Science Foundation of Top Talent of SZTU(GDRC202204)Shenzhen Science and Technology Program(JCYJ20210324095610027)+1 种基金Guangdong Basic and Applied Basic Research Foundation(2023A1515030152)National Natural Science Foundation of China(62271322)。
文摘The progress of on-chip optical communication relies on integrated multi-dimensional mode(de)multiplexers to enhance communication capacity and establish comprehensive networks.However,existing multi-dimensional(de)multiplexers,involving modes and wavelengths,face limitations due to their reliance on single-directional total internal reflection and multi-level mode conversion based on directional coupling principles.These constraints restrict their potential for full-duplex functionality and highly integrated communication.We solve these problems by introducing a photonic-like crystal-connected bidirectional micro-ring resonator array(PBMRA)and apply it to duplex mode-wavelength multiplexing communication.The directional independence of total internal reflection and the cumulative effect of the subwavelength-scale pillar within the single-level photonic crystal enable bidirectional mode and wavelength multiplexed signals to transmit among multi-pair nodes without interference,improving on-chip integration in single-level mode conversion.As a proof of concept,we fabricated a nine-channel bidirectional multi-dimensional(de)multiplexer,featuring three wavelengths and three TE modes,compactly housed within a footprint of 80μm×80μm,which efficiently transmits QPSK-OFDM signals at a rate of 216 Gbit/s,achieving a bit error rate lower than 10^(-4).Leveraging the co-ring transmission characteristic and the orthogonality of the mode-wavelength channel,this(de)multiplexer also enables a doubling of communication capacity using two physical transmission channels.
基金supported by the National Natural Science Foundation of China(Grant No.62271322)Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515030152)+3 种基金Shenzhen Science and Technology Program(Grant No.JCYJ20210324095610027)Natural Science Foundation of Top Talent of SZTU(Grant No.GDRC202204)Qianxinan Prefecture Science and Technology Plan Project(Grant No.2023123)Scientific Research Fund Project of Minzu Normal University of Xingyi(Grant No.23XYZD07)。
文摘The advancement of integrated optical communication networks necessitates the deployment of on-chip beam splitters for efficient signal interconnections at network nodes.However,the pursuit of micron-scale beam splitting with large corners and reducing the device footprint to boost connection flexibility often results in phase mismatches.These mismatches,which stem from radiation modes and backward scattering,pose significant obstacles in creating highly integrated and interference-resistant connections.To address this,we introduce a solution based on the topological valley-contrasting state generated by photonic crystals with opposing valley Chern numbers,manifested in a harpoon-shaped structure designed to steer the splitting channels.This approach enables adiabatic mode field evolution over large corners,capitalizing on the robust phase modulation capabilities and topological protection provided by the subwavelength-scale valley-contrasting state.Our demonstration reveals that beam splitters with large corners of 60°,90°,and 120°exhibit insertion loss fluctuations below 2.7 dB while maintaining a minimal footprint of 8.8μm×8.8μm.As a practical demonstration,these devices facilitate three-channel signal connections,successfully transmitting quadrature phase shift keying signals at 3.66 Tbit/s with bit error rates below the forward error correction threshold,demonstrating performance comparable to that in defects scenarios.By harnessing the unidirectional excitation feature,we anticipate significant enhancements in the capabilities of signal distribution and connection networks through a daisy chain configuration.
基金National Natural Science Foundation of China(61805087)Science and Technology Program of Guangzhou(2019050001,202102020604,202201010351)+2 种基金Natural Science Foundation of Guangdong Province(2018A030313368)Special Program on Key Fields for Colleges and Universities of Guangdong Province(2021ZDZX1048)Guangdong Provincial Key Laboratory of Optical Information Materials and Technology(2023B1212060065)。
文摘Liquid crystal(LC)photonic devices have attracted intensive attention in recent decades,due to the merits of tunability,cost-effectiveness,and high efficiency.However,the precise and efficient simulation of large-scale three-dimensional electrically stimulated LC photonic devices remains challenging and resource consuming.Here we report a straightforward nonuniform finite difference method(NFDM)for efficiently simulating largescale LC photonic devices by employing a spatially nonuniform mesh grid.
基金This project was funded by National Natural Science Foundation of China(61805149,62101334,12047539,U1701661)Guangdong Basic and Applied Basic Research Foundation(2020A1515011392,2020A1515110572,2019A1515111153,2021A1515011762)+4 种基金Shenzhen Fundamental Research Program(JCYJ20200109144001800,JCYJ20180507182035270)Science and Technology Project of Shenzhen(GJHZ20180928160407303)Shenzhen Universities Stabilization Support Program(SZWD2021013)Shenzhen Excellent Scientific and Technological Innovative Talent Training Program(RCBS20200714114818094)China Postdoctoral Science Foundation(2020M682867).
文摘The emergence of cylindrical vector beam(CVB)multiplexing has opened new avenues for high-capacity optical communication.Although several configurations have been developed to couple/separate CVBs,the CVB multiplexer/demultiplexer remains elusive due to lack of effective off-axis polarization control technologies.Here we report a straightforward approach to realize off-axis polarization control for CVB multiplexing/demultiplexing based on a metal–dielectric–metal metasurface.We show that the left-and right-handed circularly polarized(LHCP/RHCP)components of CVBs are independently modulated via spin-to-orbit interactions by the properly designed metasurface,and then simultaneously multiplexed and demultiplexed due to the reversibility of light path and the conservation of vector mode.We also show that the proposed multiplexers/demultiplexers are broadband(from 1310 to 1625 nm)and compatible with wavelength-division-multiplexing.As a proof of concept,we successfully demonstrate a four-channel CVB multiplexing communication,combining wavelength-division-multiplexing and polarization-division-multiplexing with a transmission rate of 1.56 Tbit/s and a bit-error-rate of 10^(−6) at the receive power of−21.6 dBm.This study paves the way for CVB multiplexing/demultiplexing and may benefit high-capacity CVB communication.
基金National Natural Science Foundation of China(12047539,61805149,62101334)Guangdong Basic and Applied Basic Research Foundation(2019A1515111153,2020A1515011392,2020A1515110572,2021A1515011762)+4 种基金Shenzhen Fundamental Research Program(JCYJ20180507182035270,JCYJ20200109144001800)Science and Technology Project of Shenzhen(GJHZ20180928160407303)Shenzhen Universities Stabilization Support Program(SZWD2021013)Shenzhen Excellent Scientific and Technological Innovative Talent Training Program(RCBS20200714114818094)China Postdoctoral Science Foundation(2020M682867)。
文摘Optical logical operations demonstrate the key role of optical digital computing,which can perform general-purpose calculations and possess fast processing speed,low crosstalk,and high throughput.The logic states usually refer to linear momentums that are distinguished by intensity distributions,which blur the discrimination boundary and limit its sustainable applications.Here,we introduce orbital angular momentum(OAM)mode logical operations performed by optical diffractive neural networks(ODNNs).Using the OAM mode as a logic state not only can improve the parallel processing ability but also enhance the logic distinction and robustness of logical gates owing to the mode infinity and orthogonality.ODNN combining scalar diffraction theory and deep learning technology is designed to independently manipulate the mode and spatial position of multiple OAM modes,which allows for complex multilight modulation functions to respond to logic inputs.We show that few-layer ODNNs successfully implement the logical operations of AND,OR,NOT,NAND,and NOR in simulations.The logic units of XNOR and XOR are obtained by cascading the basic logical gates of AND,OR,and NOT,which can further constitute logical half-adder gates.Our demonstrations may provide a new avenue for optical logical operations and are expected to promote the practical application of optical digital computing.
基金support from National Key R&D Program of China(2021YFB3600602,zcgx2022002L)National Natural Science Foundation of China(52175403 and 61805087)+4 种基金Natural Science Foundation of Guangdong Province(2021A1515010623)Special Program on Key Fields for Colleges and Universities of Guangdong Province(2021ZDZX1048)Science and Technology Program of Guangzhou(202102020604)Guangdong Provincial Key Laboratory of Optical Information Materials and Technology(2017B030301007)MOE International Laboratory for Optical Information Technologies,and the 111 Project.G.H acknowledges the NTU Start-up Grant.
文摘Microlens arrays(MLAs)based on the selective wetting have opened new avenues for developing compact and miniaturized imaging and display techniques with ultrahigh resolution beyond the traditional bulky and volumetric optics.However,the selective wetting lenses explored so far have been constrained by the lack of precisely defined pattern for highly controllable wettability contrast,thus limiting the available droplet curvature and numerical aperture,which is a major challenge towards the practical high-performance MLAs.Here we report a mold-free and self-assembly approach of mass-production of scalable MLAs,which can also have ultrasmooth surface,ultrahigh resolution,and the large tuning range of the curvatures.The selective surface modification based on tunable oxygen plasma can facilitate the precise pattern with adjusted chemical contrast,thus creating large-scale microdroplets array with controlled curvature.The numerical aperture of the MLAs can be up to 0.26 and precisely tuned by adjusting the modification intensity or the droplet dose.The fabricated MLAs have high-quality surface with subnanometer roughness and allow for record-high resolution imaging up to equivalently 10,328 ppi,as we demonstrated.This study shows a cost-effective roadmap for mass-production of high-performance MLAs,which may find applications in the rapid proliferating integral imaging industry and high-resolution display.
基金Program of Fundamental Rescarch of Science and Technology Planning Project of Shenzhen Munipality(JCYJ20180507182035270)Science and Technology Planning Project of Guangdong Province(2016B050501005)+3 种基金Science and Technology Project of Shenzhen(ZDSYS201707271014468)International Collaborative Laboratory of 2D Materials for Opeoelectronics Science and Technology(2DMOST2018003)National Natural Science Foundation of China(61805087,61805149)Natural Science Foundation of Guangdong Province(2016A030310065,2018A030313368,2020A1515011392).
文摘Photonic spin Hall efect(SHE)provides new opportunities for achieving spin-based photonics applications.However,flexibly manipulating the spin-dependent sltting(SDS)of photonic SHE and imposing extra phase modulation on the two spin components are always a challenge.Here,a controllable SHE mechanism based on phase function construction is reported.It is conduded that the phases with specific functional structures performing a coordinate translation are equivalent to integrating a gradient phase to the original phases.Hence,the original phase can be used for independent phase modulation,and the gradient phase originating from the co-ordinate translation is capable of manipulating the SDS.A metasurface with Pancharatnam-Berry phase that can impose conjugate phases to the two spin components of light is fabricated to verify this mechanism.By shifing the light position,the SDS is continuously manipulated in the visible region,which is successfully used for detecting the polarization llipticity.The extra phase modulation is also performed with the original phase and thus enables measuring singular beams.It is anticipated that the controllable SHE manipulation method may open new avenues in the fields of spin photonics,optical sensing,optical communications,etc.
基金Shenzhen Peacock Plan(20180521645C,20180921273B)China Postdoctoral Science Foundation(2020M682867)+5 种基金Shenzhen Excellent Scientific and Technological Innovative Talent Training Program(RCBS20200714114818094)Shenzhen Universities Stabilization Support Program(SZWD2021013)Science and Technology Project of Shenzhen(GJHZ20180928160407303)Shenzhen Fundamental Research Program(JCYJ20210324095611030,JCYJ20210324095610027)Basic and Applied Basic Research Foundation of Guangdong Province(2019A1515111153,2020A1515011392,2020A1515110572,2021A1515011762)National Natural Science Foundation of China(12047539,61805149,62101334)。
文摘Metasurfaces composed of spatially arranged ultrathin subwavelength elements are promising photonic devices for manipulating optical wavefronts,with potential applications in holography,metalens,and multiplexing communications.Finding microstructures that meet light modulation requirements is always a challenge in designing metasurfaces,where parameter sweep,gradient-based inverse design,and topology optimization are the most commonly used design methods in which the massive electromagnetic iterations require the design computational cost and are sometimes prohibitive.Herein,we propose a fast inverse design method that combines a physicsbased neural network surrogate model(NNSM)with an optimization algorithm.The NNSM,which can generate an accurate electromagnetic response from the geometric topologies of the meta-atoms,is constructed for electromagnetic iterations,and the optimization algorithm is used to search for the on-demand meta-atoms from the phase library established by the NNSM to realize an inverse design.This method addresses two important problems in metasurface design:fast and accurate electromagnetic wave phase prediction and inverse design through a single phase-shift value.As a proof-of-concept,we designed an orbital angular momentum(de)multiplexer based on a phase-type metasurface,and 200 Gbit/s quadrature-phase shift-keying signals were successfully transmitted with a bit error rate approaching 1.67×10^(-6).Because the design is mainly based on an optimization algorithm,it can address the“one-to-many”inverse problem in other micro/nano devices such as integrated photonic circuits,waveguides,and nano-antennas.
基金National Natural Science Foundation of China(NSFC)(61605155,61627812)Fundamental Research Funds for the Central Universities
文摘Conventional periodic structures usually have nontunable refractive indices and thus lead to immutable photonic bandgaps. A periodic structure created in an ultracold atoms ensemble by externally controlled light can overcome this disadvantage and enable lots of promising applications. Here, two novel types of optically induced square lattices, i.e., the amplitude and phase lattices, are proposed in an ultracold atoms ensemble by interfering four ordinary plane waves under different parameter conditions. We demonstrate that in the far-field regime, the atomic amplitude lattice with high transmissivity behaves similarly to an ideal pure sinusoidal amplitude lattice, whereas the atomic phase lattices capable of producing phase excursion across a weak probe beam along with high transmissivity remains equally ideal. Moreover, we identify that the quality of Talbot imaging about a phase lattice is greatly improved when compared with an amplitude lattice. Such an atomic lattice could find applications in alloptical switching at the few photons level and paves the way for imaging ultracold atoms or molecules both in the near-field and in the far-field with a nondestructive and lensless approach.
