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
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
Spin-decoupled metasurfaces have attracted extensive attention in recent years due to their broad applicability in diverse fields,such as reflector antennas,vortex beam detection,and advanced imaging systems.Typically...Spin-decoupled metasurfaces have attracted extensive attention in recent years due to their broad applicability in diverse fields,such as reflector antennas,vortex beam detection,and advanced imaging systems.Typically,these metasurfaces rely on the interplay between geometric and propagation phases.However,these two phases exhibit fundamentally different behaviors regarding wavelength dependence:geometric phase remains relatively stable across varying wavelengths,whereas propagation phase,governed by structural resonances and material dispersion,is inherently wavelength-sensitive.As a result,achieving spin-decoupled metasurfaces with independent bandwidth control remains a significant challenge.In this work,we utilize the topological phase associated with non-Hermitian exceptional points(EPs)to propose an innovative strategy for designing spin-decoupled metasurfaces.By systematically tuning the structural parameters of the unit cells,we achieve a complete and continuous 2πmodulation of the topological phase across various pre-designed spectral regions.When combined synergistically with the conventional geometric phase,we propose a spin-decoupled metasurface with independently controllable bandwidth properties.Specifically,the metasurface exhibits broadband behavior under righthanded circular polarization(RCP)illumination and controllable narrowband operation under left-handed circular polarization(LCP)illumination.This novel approach,to our knowledge,offers unprecedented flexibility in tailoring the spectral response of spin-decoupled metasurfaces.This advancement opens new possibilities for dynamically tunable metasurface devices,facilitating diverse practical applications,such as polarization modulation,adaptive filtering,optical communications,and sensing technologies.展开更多
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(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National Natural Science Foundation of China(62205343,U24A6010,52488301).
文摘Spin-decoupled metasurfaces have attracted extensive attention in recent years due to their broad applicability in diverse fields,such as reflector antennas,vortex beam detection,and advanced imaging systems.Typically,these metasurfaces rely on the interplay between geometric and propagation phases.However,these two phases exhibit fundamentally different behaviors regarding wavelength dependence:geometric phase remains relatively stable across varying wavelengths,whereas propagation phase,governed by structural resonances and material dispersion,is inherently wavelength-sensitive.As a result,achieving spin-decoupled metasurfaces with independent bandwidth control remains a significant challenge.In this work,we utilize the topological phase associated with non-Hermitian exceptional points(EPs)to propose an innovative strategy for designing spin-decoupled metasurfaces.By systematically tuning the structural parameters of the unit cells,we achieve a complete and continuous 2πmodulation of the topological phase across various pre-designed spectral regions.When combined synergistically with the conventional geometric phase,we propose a spin-decoupled metasurface with independently controllable bandwidth properties.Specifically,the metasurface exhibits broadband behavior under righthanded circular polarization(RCP)illumination and controllable narrowband operation under left-handed circular polarization(LCP)illumination.This novel approach,to our knowledge,offers unprecedented flexibility in tailoring the spectral response of spin-decoupled metasurfaces.This advancement opens new possibilities for dynamically tunable metasurface devices,facilitating diverse practical applications,such as polarization modulation,adaptive filtering,optical communications,and sensing technologies.
