We demonstrate an effective and optimal strategy for generating spatially resolved longitudinal spin angular momentum(LSAM)in optical tweezers by tightly focusing the first-order spirally polarized vector(SPV)beams wi...We demonstrate an effective and optimal strategy for generating spatially resolved longitudinal spin angular momentum(LSAM)in optical tweezers by tightly focusing the first-order spirally polarized vector(SPV)beams with zero intrinsic angular momentum into a refractive index stratified medium.The stratified medium gives rise to a spherically aberrated intensity profile near the focal region of the optical tweezers,with off-axis intensity lobes in the radial direction possessing opposite LSAM(helicities corresponding toσ=+1 and−1)compared to the beam center.We trap mesoscopic birefringent particles in an off-axis intensity lobe as well as at the beam center by modifying the trapping plane and observe particles spinning in opposite directions depending on their location.The direction of rotation depends on the particle size with larger particles spinning either clockwise or anticlockwise depending on the direction of spirality of the polarization of the SPV beam after tight focusing,while smaller particles spin in both directions depending on their spatial locations.Numerical simulations support our experimental observations.Our results introduce new avenues in spin-orbit optomechanics to facilitate novel yet straightforward avenues for exotic and complex particle manipulation in optical tweezers.展开更多
Based on the extended Huygens-Fresnel principle, the propagation of cylindrical vector beams in a turbulent atmosphere is investigated. The intensity distribution and the polarization degree of beams on propagation ar...Based on the extended Huygens-Fresnel principle, the propagation of cylindrical vector beams in a turbulent atmosphere is investigated. The intensity distribution and the polarization degree of beams on propagation are studied. It is found that the beam profile has a Gaussian shape under the influence of the atmospheric turbulence, and the polarization distribution shows a dip in the cross section as the beam propagates in the turbulent atmosphere. It is also found that the beam profile and the polarization distribution are closely related to beam parameter and atmospheric turbulence.展开更多
Due to the large exciton binding energy,two-dimensional(2D)transition metal dichalcogenides(TMDCs)provide an ideal platform for studying excitonic states and related photonics and optoelectronics.Polarization states l...Due to the large exciton binding energy,two-dimensional(2D)transition metal dichalcogenides(TMDCs)provide an ideal platform for studying excitonic states and related photonics and optoelectronics.Polarization states lead to distinct light-matter interactions which are of great importance for device applications.In this work,we study polarized photoluminescence spectra from intralayer exciton and indirect exciton in WS_(2) and WSe_(2) atomic layers,and interlayer exciton in WS_(2)/WSe_(2) heterostructures by radially and azimuthally polarized cylindrical vector laser beams.We demonstrated the same in-plane and out-of-plane polarization behavior from the intralayer and indirect exciton.Moreover,with these two laser modes,we obtained interlayer exciton in WS_(2)/WSe_(2) heterostructures with stronger out-of-plane polarization,due to the formation of vertical electric dipole moment.展开更多
Based on angular amplitude modulation of orthogonal base vectors in common-path interference method, we propose an interesting type of hybrid vector beams with unprecedented azimuthal polarization gradient and demonst...Based on angular amplitude modulation of orthogonal base vectors in common-path interference method, we propose an interesting type of hybrid vector beams with unprecedented azimuthal polarization gradient and demonstrate in experiment. Geometrically, the configured azimuthal polarization gradient is indicated by intriguing mapping tracks of angular polarization states on Poincaré sphere, more than just conventional circles for previously reported vector beams. Moreover, via tailoring relevant parameters, more special polarization mapping tracks can be handily achieved. More noteworthily, the designed azimuthal polarization gradients are found to be able to induce azimuthally non-uniform orbital angular momentum density, while generally uniform for circle-track cases, immersing in homogenous intensity background whatever base states are. These peculiar features may open alternative routes for new optical effects and applications.展开更多
Vector beams with spiral phase and spatially varying polarization profiles have many applications from optical micromanipulation to materials processing. Here, we propose and demonstrate an atomic spatial mode extract...Vector beams with spiral phase and spatially varying polarization profiles have many applications from optical micromanipulation to materials processing. Here, we propose and demonstrate an atomic spatial mode extracting scheme for the vector beam based on polarization-dependent absorption in the atom vapor. By employing the linear polarization pump beam which induces polarization sensitive absorption in the atomic ensemble, a counter-propagated weak probe vector beam is extracted by spatial absorption, and extracted part still maintains the original polarization and the vortex phase.The topological charges of the extracted mode are verified by interfering with the Gaussian beam, and it can be found that the orbital angular momentum is conserved in the extracting process. Our work will have potential applications in non-destructive spatial mode identification, and is also useful for studying higher-dimensional quantum information based on atomic ensembles.展开更多
We propose a method for generating double-ring-shaped vector beams. A step phase introduced by a spatial light modulator（SLM） first makes the incident laser beam have a nodal cycle. This phase is dynamic in nature b...We propose a method for generating double-ring-shaped vector beams. A step phase introduced by a spatial light modulator（SLM） first makes the incident laser beam have a nodal cycle. This phase is dynamic in nature because it depends on the optical length. Then a Pancharatnam–Berry phase（PBP） optical element is used to manipulate the local polarization of the optical field by modulating the geometric phase. The experimental results show that this scheme can effectively create double-ring-shaped vector beams. It provides much greater flexibility to manipulate the phase and polarization by simultaneously modulating the dynamic and the geometric phases.展开更多
Broadband polarization measurement plays a crucial role in numerous fields,spanning from fundamental physics to a wide range of practical applications.However,traditional approaches typically rely on combinations of v...Broadband polarization measurement plays a crucial role in numerous fields,spanning from fundamental physics to a wide range of practical applications.However,traditional approaches typically rely on combinations of various dispersive optical elements,requiring bulky systems and complicated time-consuming multiple procedures.Here we have achieved broadband spectropolarimetry based on single-shot images for spatial intensity distributions of polychromatic vector beams.A custom-designed diffractive optical element and a vortex retarder convert the incident polychromatic waves into structured vector beams:the former diffracts light of different wavelengths into concentric circles of different radii,while the latter codes their polarization information into intensity distributions along the azimuthal direction.The validation experiments verify our exceptional measurement accuracy(RMS errors<1%)for each Stokes component in the visible light range(400-700 nm),with good spectral(<0.8 nm)and temporal(an output rate of 100 Hz)resolutions.We have further employed our broadband polarimeter to study the mutarotation of glucose,making direct observations of temporal evolutions of chemical reactions accessible.Our work has significantly broadened the toolboxes of spectropolarimetry,which can potentially incubate various disruptive applications that depend on broadband polarization measurements.展开更多
Perfect vortices,recognized for their distinct ring profile that remains independent of the topological charge,present significant challenges in generation due to the precise control needed over both phase and polariz...Perfect vortices,recognized for their distinct ring profile that remains independent of the topological charge,present significant challenges in generation due to the precise control needed over both phase and polarization.In this work,we introduce and validate a new approach for generating these beams,allowing the selection of diffferent azimuthally-variant phase gradients and vector states,thereby enabling full control over the phase and polarization patterns of perfect vortices.Using dual-functional silicon metaoptics,we achieve the compact generation of a novel class of perfect vortices,termed azimuthally-variant perfect vector beams.The optical characterization of the generated beams,performed through a filtering method,confirms their intrinsic azimuthally-variant vectorial nature.These beams exhibit unique properties that promise valuable applications in optical tweezing,the manipulation of low-refractive-index particles,the trapping of cold atoms,and high-capacity communications.展开更多
Cylindrical vector beams(CVBs),characterized by their spatially varying polarization and axial symmetry,have emerged as powerful tools for engineering light–matter interactions at the nanoscale.Unlike conventional li...Cylindrical vector beams(CVBs),characterized by their spatially varying polarization and axial symmetry,have emerged as powerful tools for engineering light–matter interactions at the nanoscale.Unlike conventional linearly polarized beams,tightly focused CVBs can generate strong longitudinal electric or magnetic field components,enabling the selective excitation of specific multipolar modes and various resulting modes in optical nanostructures.This unique field configuration facilitates the excitation of various optical phenomena such as anapole states,dark modes,Fano resonances,optical magnetism,and enhanced nonlinear optical responses,which are challenging to achieve with traditional illumination.We summarize recent advancements in nanophotonic phenomena/effects driven by CVB excitation,illustrated through seminal studies in plasmonic,dielectric,or hybrid nanostructures,offering promising opportunities for applications in imaging,sensing,optical trapping,quantum information processing,etc.We discuss how enhanced electromagnetic field confinement,increased coupling efficiency,and precise control over resonant scattering can lead to advanced nanophotonic phenomena/effects under CVB illumination.The insights presented here aim to guide future developments in structured light–matter interaction and inspire the design of advanced nanophotonic systems.展开更多
On-chip devices for generating pre-designed vectorial optical fields(VOFs)under surface wave(SW)excitations are highly desired in integrated photonics.However,conventional devices are usually of large footprints,low e...On-chip devices for generating pre-designed vectorial optical fields(VOFs)under surface wave(SW)excitations are highly desired in integrated photonics.However,conventional devices are usually of large footprints,low efficiencies,and limited wave-control capabilities.Here,we present a generic approach to design ultra-compact on-chip devices that can efficiently generate pre-designed VOFs under SW excitations,and experimentally verify the concept in terahertz(THz)regime.We first describe how to design SW-excitation metasurfaces for generating circularly polarized complex beams,and experimentally demonstrate two meta-devices to realize directional emission and focusing of THz waves with oppo-site circular polarizations,respectively.We then establish a systematic approach to construct an integrated device via merging two carefully designed metasurfaces,which,under SW excitations,can separately produce pre-designed far-field patterns with different circular polarizations and generate target VOF based on their interference.As a proof of con-cept,we demonstrate experimentally a meta-device that can generate a radially polarized Bessel beam under SW excita-tion at~0.4 THz.Experimental results agree well with full-wave simulations,collectively verifying the performance of our device.Our study paves the road to realizing highly integrated on-chip functional THz devices,which may find many ap-plications in biological sensing,communications,displays,image multiplexing,and beyond.展开更多
We propose a method for generating an all-fiber cylindrical vector beam(CVB)using a fiber Bragg grating(FBG)inscribed in a ring core fiber(RCF).The FBGs are inscribed using the femtosecond laser phase mask scanning te...We propose a method for generating an all-fiber cylindrical vector beam(CVB)using a fiber Bragg grating(FBG)inscribed in a ring core fiber(RCF).The FBGs are inscribed using the femtosecond laser phase mask scanning technique,chosen for its large ring core diameter and low photosensitivity of the RCF.Additionally,a lateral offset splicing spot is introduced to couple the fundamental mode to the second-order modes.Switchable LP_(01)and LP_(11)mode lasers can be achieved.Meanwhile,azimuthally and radially polarized CVBs are successfully realized by adjusting the polarization controllers.展开更多
The possibility to achieve unprecedented multiplexing of light-matter interaction in nanoscale is of virtue importance from both fundamental science and practical application points of view. Cylindrical vector beams(C...The possibility to achieve unprecedented multiplexing of light-matter interaction in nanoscale is of virtue importance from both fundamental science and practical application points of view. Cylindrical vector beams(CVBs) manifested as polarization vortices represent a robust and emerging degree of freedom for information multiplexing with increased capacities. Here, we propose and demonstrate massivelyencoded optical data storage(ODS) by harnessing spatially variant electric fields mediated by segmented CVBs. By tight focusing polychromatic segmented CVBs to plasmonic nanoparticle aggregates, recordhigh multiplexing channels of ODS through different combinations of polarization states and wavelengths have been experimentally demonstrated with a low error rate. Our result not only casts new perceptions for tailoring light-matter interactions utilizing structured light but also enables a new prospective for ultra-high capacity optical memory with minimalist system complexity by combining CVB’s compatibility with fiber optics.展开更多
We reporte and demonstrate a solid-state laser to achieve controlled generation of order-switchable cylindrical vector beams(CVBs).In the cavity,a group of vortex wave plates(VWPs)with two quarter-wave plates between ...We reporte and demonstrate a solid-state laser to achieve controlled generation of order-switchable cylindrical vector beams(CVBs).In the cavity,a group of vortex wave plates(VWPs)with two quarter-wave plates between the VWPs was utilized to achieve mode conversion and order-switch of CVBs.By utilizing two VWPs of first and third orders,the second and fourth order CVBs were obtained,with mode purities of 96.8%and 94.8%,and sloping efficiencies of 4.45%and 3.06%,respectively.Furthermore,by applying three VWPs of first,second,and third orders,the mode-switchable Gaussian beam,second,fourth,and sixth order CVBs were generated.展开更多
This paper reports the experimental realization of efficiently sorting vector beams by polarization topological charge （PTC）. The PTC of a vector beam can be defined as the repetition number of polarization state ch...This paper reports the experimental realization of efficiently sorting vector beams by polarization topological charge （PTC）. The PTC of a vector beam can be defined as the repetition number of polarization state change along the azimuthal axis, while its sign stands for the rotating direction of the polarization. Here, a couple of liquid crystal Pancharatnam-Berry optical dements （PBOEs） have been used to introduce conjugated spatial phase modulations for two orthogonal circular polarization states. Applying these PBOEs in a 4-foptical system, our experiments show the setup can work for PTC sorting with a separation efficiency of more than 58%. This work provides an effective way to decode information from different PTCs, which may be interesting in many fields, especially in optical communication.展开更多
We experimentally obtain cylindrical vector beams（CVBs） in a passively mode-locked fiber laser based on nonlinear polarization rotation. A mode-selective coupler composed of both a single-mode fiber（SMF） and a two...We experimentally obtain cylindrical vector beams（CVBs） in a passively mode-locked fiber laser based on nonlinear polarization rotation. A mode-selective coupler composed of both a single-mode fiber（SMF） and a twomode fiber（TMF） is incorporated into the cavity to act as a mode converter from LP01 mode to LP11 mode with broad spectral bandwidth. CVBs in different mode-locked states including single-pulse, multi-pulse, and bound pulse are obtained, for the first time to our best knowledge. The ultrafast CVBs with different operation states have potential applications in many fields such as laser beam machining, nanoparticle manipulation, and so on.展开更多
The polarization evolution of vector beams(VBs) generated by q-plates is investigated theoretically and experimentally.An analytical model is developed for the VB created by a general quarter-wave q-plate based on vec...The polarization evolution of vector beams(VBs) generated by q-plates is investigated theoretically and experimentally.An analytical model is developed for the VB created by a general quarter-wave q-plate based on vector diffraction theory.It is found that the polarization distribution of VBs varies with position and the value q.In particular,for the incidence of circular polarization,the exit vector vortex beam has polarization states that cover the whole surface of the Poincarésphere,thereby constituting a full Poincarébeam.For the incidence of linear polarization,the VB is not cylindrical but specularly symmetric,and exhibits an azimuthal spin splitting.These results are in sharp contrast with those derived by the commonly used model,i.e.,regarding the incident light as a plane wave.By implementing q-plates with dielectric metasurfaces,further experiments validate the theoretical results.展开更多
We introduce the Stokes scintillation indices and the corresponding overall Stokes scintillations for quantitatively studying the fluctuations of both the intensity and polarization of an optical vector beam transmitt...We introduce the Stokes scintillation indices and the corresponding overall Stokes scintillations for quantitatively studying the fluctuations of both the intensity and polarization of an optical vector beam transmitting through the atmospheric turbulence.With the aid of the multiple-phase-screen method,we examine the Stokes fluctuations of a radially polarized beam in Kolmogorov turbulence numerically.The results show that the overall scintillation for the intensity distribution is always larger than the overall scintillation for the polarization-dependent Stokes parameters,which indicates that the polarization state of a vector beam is stabler than its intensity distribution in the turbulence.We interpret the results with the depolarization effect of the vector beam in turbulence.The findings in this work may be useful in free-space optical communications utilizing vector beams.展开更多
Toroidal multipole is a special current distribution that has many different characteristics from electric multipole and magnetic multipole distributions.Because of its special properties,the toroidal dipole is a rese...Toroidal multipole is a special current distribution that has many different characteristics from electric multipole and magnetic multipole distributions.Because of its special properties,the toroidal dipole is a research hotspot in the field of metamaterials and nanophotonics.However,the low scattering of the toroidal dipole moment makes its excitation a challenging task.At present,there are relatively few studies on its specific engineering applications.In this paper,by slotting in the rectangular cavity,the excitation of an equivalent toroidal dipole is successfully achieved over a wide frequency range of 53-58 GHz.Results indicate that under the action of the toroidal dipole,the TE_(10)mode electromagnetic waves transmitted in the rectangular waveguide are converted into vector beams and are radiated outwards.Further adjusting the spatial distribution of the magnetic dipoles in the toroidal dipoles yields results that indicate that the resonance mode in the slot is still dominated by the magnetic toroidal dipole moment,and the electromagnetic waves radiating outward are vortex beams carrying vector polarization.The scattered energy of each dipole moment inside the antenna is calculated.This calculation verifies that the mass of the vector beam and vector vortex beam is closely related to the toroidal dipole supported by this antenna.The proposed structure can be applied to explorations in vortex filtering,in photon entanglement,and in the photonic spin Hall effect.展开更多
We present the generation of the nanosecond cylindrical vector beams(CVBs)in a two-mode fiber(TMF)and its applications of stimulated Raman scattering.The nanosecond(1064 nm,10 ns,10 Hz)CVBs have been directly produced...We present the generation of the nanosecond cylindrical vector beams(CVBs)in a two-mode fiber(TMF)and its applications of stimulated Raman scattering.The nanosecond(1064 nm,10 ns,10 Hz)CVBs have been directly produced with mode conversion efficiency of~18 d B(98.4%)via an acoustically induced fiber grating,and then the stimulated Raman scattering signal is generated based on the transmission of the nanosecond CVBs in a 100-m-long TMF.The transverse mode intensity and polarization distributions of the first-order Stokes shift component(1116.8 nm)are consistent with the nanosecond CVBs pump pulse.展开更多
Vector structured beams(VSBs)offer infinite eigenstates and open up new possibilities for highcapacity optical and quantum communications by the multiplexing of the states.Therefore,the sorting and measuring of VSBs a...Vector structured beams(VSBs)offer infinite eigenstates and open up new possibilities for highcapacity optical and quantum communications by the multiplexing of the states.Therefore,the sorting and measuring of VSBs are extremely important.However,the efficient manipulations of a large number of VSBs have simultaneously remained challenging up to now,especially in integrated optical systems.Here,we propose a compact spin-multiplexed diffractive metasurface capable of continuously sorting and detecting arbitrary VSBs through spatial intensity separation.By introducing a diffractive optical neural network with cascaded metasurface systems,we demonstrate arbitrary VSBs sorters that can simultaneously identify Laguerre–Gaussian modes(l=−4 to 4,p=1 to 4),Hermitian–Gaussian modes(m=1 to 4,n=1 to 3),and Bessel–Gaussian modes(l=1 to 12).Such a sorter for arbitrary VSBs could revolutionize applications in integrated and high-dimensional optical communication systems.展开更多
基金the SERB,Department of Science and Technology,Government of India(Project No.EMR/2017/001456)aIISER Kolkata IPh.D fellowship for research.
文摘We demonstrate an effective and optimal strategy for generating spatially resolved longitudinal spin angular momentum(LSAM)in optical tweezers by tightly focusing the first-order spirally polarized vector(SPV)beams with zero intrinsic angular momentum into a refractive index stratified medium.The stratified medium gives rise to a spherically aberrated intensity profile near the focal region of the optical tweezers,with off-axis intensity lobes in the radial direction possessing opposite LSAM(helicities corresponding toσ=+1 and−1)compared to the beam center.We trap mesoscopic birefringent particles in an off-axis intensity lobe as well as at the beam center by modifying the trapping plane and observe particles spinning in opposite directions depending on their location.The direction of rotation depends on the particle size with larger particles spinning either clockwise or anticlockwise depending on the direction of spirality of the polarization of the SPV beam after tight focusing,while smaller particles spin in both directions depending on their spatial locations.Numerical simulations support our experimental observations.Our results introduce new avenues in spin-orbit optomechanics to facilitate novel yet straightforward avenues for exotic and complex particle manipulation in optical tweezers.
基金Project supported by the National Natural Science Foundation of China(Grant No.60977068)the Key Project of Science and Technology of Fujian Province,China(Grant No.2007H0027)the Natural Science Foundation of Fujian Province,China (Grant No.A0810012)
文摘Based on the extended Huygens-Fresnel principle, the propagation of cylindrical vector beams in a turbulent atmosphere is investigated. The intensity distribution and the polarization degree of beams on propagation are studied. It is found that the beam profile has a Gaussian shape under the influence of the atmospheric turbulence, and the polarization distribution shows a dip in the cross section as the beam propagates in the turbulent atmosphere. It is also found that the beam profile and the polarization distribution are closely related to beam parameter and atmospheric turbulence.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.91850116,51772084,52022029,and U19A2090)Hunan Provincial Natural Science Foundation of China(Grant Nos.2018RS3051 and 2018WK4004)the Key Program of the Hunan Provincial Science and Technology Department,China(Grant No.2019XK2001).
文摘Due to the large exciton binding energy,two-dimensional(2D)transition metal dichalcogenides(TMDCs)provide an ideal platform for studying excitonic states and related photonics and optoelectronics.Polarization states lead to distinct light-matter interactions which are of great importance for device applications.In this work,we study polarized photoluminescence spectra from intralayer exciton and indirect exciton in WS_(2) and WSe_(2) atomic layers,and interlayer exciton in WS_(2)/WSe_(2) heterostructures by radially and azimuthally polarized cylindrical vector laser beams.We demonstrated the same in-plane and out-of-plane polarization behavior from the intralayer and indirect exciton.Moreover,with these two laser modes,we obtained interlayer exciton in WS_(2)/WSe_(2) heterostructures with stronger out-of-plane polarization,due to the formation of vertical electric dipole moment.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0303800)the National Natural Science Foundation of China(Grant Nos.11634010,61675168,91850118,11774289,and 11804277)+1 种基金the Fundamental Research Funds for the Central Universities,China(Grant No.3102019JC008)the Basic Research Plan of Natural Science in Shaanxi Province,China(Grant Nos.2018JM1057 and 2019JM-583).
文摘Based on angular amplitude modulation of orthogonal base vectors in common-path interference method, we propose an interesting type of hybrid vector beams with unprecedented azimuthal polarization gradient and demonstrate in experiment. Geometrically, the configured azimuthal polarization gradient is indicated by intriguing mapping tracks of angular polarization states on Poincaré sphere, more than just conventional circles for previously reported vector beams. Moreover, via tailoring relevant parameters, more special polarization mapping tracks can be handily achieved. More noteworthily, the designed azimuthal polarization gradients are found to be able to induce azimuthally non-uniform orbital angular momentum density, while generally uniform for circle-track cases, immersing in homogenous intensity background whatever base states are. These peculiar features may open alternative routes for new optical effects and applications.
文摘Vector beams with spiral phase and spatially varying polarization profiles have many applications from optical micromanipulation to materials processing. Here, we propose and demonstrate an atomic spatial mode extracting scheme for the vector beam based on polarization-dependent absorption in the atom vapor. By employing the linear polarization pump beam which induces polarization sensitive absorption in the atomic ensemble, a counter-propagated weak probe vector beam is extracted by spatial absorption, and extracted part still maintains the original polarization and the vortex phase.The topological charges of the extracted mode are verified by interfering with the Gaussian beam, and it can be found that the orbital angular momentum is conserved in the extracting process. Our work will have potential applications in non-destructive spatial mode identification, and is also useful for studying higher-dimensional quantum information based on atomic ensembles.
基金Project supported by the National Natural Science Foundation of China(Grant No.11547017)the Hubei Engineering University Research Foundation,China(Grant No.z2014001)the Natural Science Foundation of Hubei Province,China(Grant No.2014CFB578)
文摘We propose a method for generating double-ring-shaped vector beams. A step phase introduced by a spatial light modulator（SLM） first makes the incident laser beam have a nodal cycle. This phase is dynamic in nature because it depends on the optical length. Then a Pancharatnam–Berry phase（PBP） optical element is used to manipulate the local polarization of the optical field by modulating the geometric phase. The experimental results show that this scheme can effectively create double-ring-shaped vector beams. It provides much greater flexibility to manipulate the phase and polarization by simultaneously modulating the dynamic and the geometric phases.
基金National Natural Science Foundation of China(62475285,61975235)Natural Science Foundation of Hunan Province(2019JJ40342)。
文摘Broadband polarization measurement plays a crucial role in numerous fields,spanning from fundamental physics to a wide range of practical applications.However,traditional approaches typically rely on combinations of various dispersive optical elements,requiring bulky systems and complicated time-consuming multiple procedures.Here we have achieved broadband spectropolarimetry based on single-shot images for spatial intensity distributions of polychromatic vector beams.A custom-designed diffractive optical element and a vortex retarder convert the incident polychromatic waves into structured vector beams:the former diffracts light of different wavelengths into concentric circles of different radii,while the latter codes their polarization information into intensity distributions along the azimuthal direction.The validation experiments verify our exceptional measurement accuracy(RMS errors<1%)for each Stokes component in the visible light range(400-700 nm),with good spectral(<0.8 nm)and temporal(an output rate of 100 Hz)resolutions.We have further employed our broadband polarimeter to study the mutarotation of glucose,making direct observations of temporal evolutions of chemical reactions accessible.Our work has significantly broadened the toolboxes of spectropolarimetry,which can potentially incubate various disruptive applications that depend on broadband polarization measurements.
文摘Perfect vortices,recognized for their distinct ring profile that remains independent of the topological charge,present significant challenges in generation due to the precise control needed over both phase and polarization.In this work,we introduce and validate a new approach for generating these beams,allowing the selection of diffferent azimuthally-variant phase gradients and vector states,thereby enabling full control over the phase and polarization patterns of perfect vortices.Using dual-functional silicon metaoptics,we achieve the compact generation of a novel class of perfect vortices,termed azimuthally-variant perfect vector beams.The optical characterization of the generated beams,performed through a filtering method,confirms their intrinsic azimuthally-variant vectorial nature.These beams exhibit unique properties that promise valuable applications in optical tweezing,the manipulation of low-refractive-index particles,the trapping of cold atoms,and high-capacity communications.
基金supported by the National Science Foundation(NSF),Division of Material Research(Grant No.DMR-2208240).
文摘Cylindrical vector beams(CVBs),characterized by their spatially varying polarization and axial symmetry,have emerged as powerful tools for engineering light–matter interactions at the nanoscale.Unlike conventional linearly polarized beams,tightly focused CVBs can generate strong longitudinal electric or magnetic field components,enabling the selective excitation of specific multipolar modes and various resulting modes in optical nanostructures.This unique field configuration facilitates the excitation of various optical phenomena such as anapole states,dark modes,Fano resonances,optical magnetism,and enhanced nonlinear optical responses,which are challenging to achieve with traditional illumination.We summarize recent advancements in nanophotonic phenomena/effects driven by CVB excitation,illustrated through seminal studies in plasmonic,dielectric,or hybrid nanostructures,offering promising opportunities for applications in imaging,sensing,optical trapping,quantum information processing,etc.We discuss how enhanced electromagnetic field confinement,increased coupling efficiency,and precise control over resonant scattering can lead to advanced nanophotonic phenomena/effects under CVB illumination.The insights presented here aim to guide future developments in structured light–matter interaction and inspire the design of advanced nanophotonic systems.
基金the financial support from National Natural Science Foundation of China (Nos. 62192771, 12374344, 12221004)National Key Research and Development Program of China (2022YFA1204700, 2020YFA0710100)+1 种基金Natural Science Foundation of Shanghai (Grant No. 23dz2260100)China Postdoctoral Science Foundation 2021TQ0077
文摘On-chip devices for generating pre-designed vectorial optical fields(VOFs)under surface wave(SW)excitations are highly desired in integrated photonics.However,conventional devices are usually of large footprints,low efficiencies,and limited wave-control capabilities.Here,we present a generic approach to design ultra-compact on-chip devices that can efficiently generate pre-designed VOFs under SW excitations,and experimentally verify the concept in terahertz(THz)regime.We first describe how to design SW-excitation metasurfaces for generating circularly polarized complex beams,and experimentally demonstrate two meta-devices to realize directional emission and focusing of THz waves with oppo-site circular polarizations,respectively.We then establish a systematic approach to construct an integrated device via merging two carefully designed metasurfaces,which,under SW excitations,can separately produce pre-designed far-field patterns with different circular polarizations and generate target VOF based on their interference.As a proof of con-cept,we demonstrate experimentally a meta-device that can generate a radially polarized Bessel beam under SW excita-tion at~0.4 THz.Experimental results agree well with full-wave simulations,collectively verifying the performance of our device.Our study paves the road to realizing highly integrated on-chip functional THz devices,which may find many ap-plications in biological sensing,communications,displays,image multiplexing,and beyond.
基金supported by the National Natural Science Foundation of China(No.62075182)the National Key Research and Development Program of China(No.2022YFB3207502)。
文摘We propose a method for generating an all-fiber cylindrical vector beam(CVB)using a fiber Bragg grating(FBG)inscribed in a ring core fiber(RCF).The FBGs are inscribed using the femtosecond laser phase mask scanning technique,chosen for its large ring core diameter and low photosensitivity of the RCF.Additionally,a lateral offset splicing spot is introduced to couple the fundamental mode to the second-order modes.Switchable LP_(01)and LP_(11)mode lasers can be achieved.Meanwhile,azimuthally and radially polarized CVBs are successfully realized by adjusting the polarization controllers.
基金the financial support from the National Key R&D Program of China (2018YFB1107200)the National Natural Science Foundation of China (91750110, 11674130, 61605061, 11674110 and 11874020)+2 种基金the Guangdong Provincial Innovation and Entrepreneurship Project (2016ZT06D081)the Natural Science Foundation of Guangdong Province (2016A030306016, 2016TQ03X981 and 2016A030308010)Pearl River S and T Nova Program of Guangzhou (201806010040)。
文摘The possibility to achieve unprecedented multiplexing of light-matter interaction in nanoscale is of virtue importance from both fundamental science and practical application points of view. Cylindrical vector beams(CVBs) manifested as polarization vortices represent a robust and emerging degree of freedom for information multiplexing with increased capacities. Here, we propose and demonstrate massivelyencoded optical data storage(ODS) by harnessing spatially variant electric fields mediated by segmented CVBs. By tight focusing polychromatic segmented CVBs to plasmonic nanoparticle aggregates, recordhigh multiplexing channels of ODS through different combinations of polarization states and wavelengths have been experimentally demonstrated with a low error rate. Our result not only casts new perceptions for tailoring light-matter interactions utilizing structured light but also enables a new prospective for ultra-high capacity optical memory with minimalist system complexity by combining CVB’s compatibility with fiber optics.
基金supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX22_3813)the Jiangsu Province Key Research and Development Program(No.BE2022143)+1 种基金the National Natural Science Foundation of China(No.62205133)the Natural Science Foundation of Jiangsu Province(No.BK20190953).
文摘We reporte and demonstrate a solid-state laser to achieve controlled generation of order-switchable cylindrical vector beams(CVBs).In the cavity,a group of vortex wave plates(VWPs)with two quarter-wave plates between the VWPs was utilized to achieve mode conversion and order-switch of CVBs.By utilizing two VWPs of first and third orders,the second and fourth order CVBs were obtained,with mode purities of 96.8%and 94.8%,and sloping efficiencies of 4.45%and 3.06%,respectively.Furthermore,by applying three VWPs of first,second,and third orders,the mode-switchable Gaussian beam,second,fourth,and sixth order CVBs were generated.
基金National Natural Science Foundation of China(NSFC)(61490710,61705132,61775142)Science and Technology Planning Project of Guangdong Province(2016B050501005)Specialized Research Fund for the Shenzhen Strategic Emerging Industries Development(JCYJ20170412105812811)
文摘This paper reports the experimental realization of efficiently sorting vector beams by polarization topological charge （PTC）. The PTC of a vector beam can be defined as the repetition number of polarization state change along the azimuthal axis, while its sign stands for the rotating direction of the polarization. Here, a couple of liquid crystal Pancharatnam-Berry optical dements （PBOEs） have been used to introduce conjugated spatial phase modulations for two orthogonal circular polarization states. Applying these PBOEs in a 4-foptical system, our experiments show the setup can work for PTC sorting with a separation efficiency of more than 58%. This work provides an effective way to decode information from different PTCs, which may be interesting in many fields, especially in optical communication.
基金supported by the National Science Foundation of Jiangsu Province(Nos.BK20161521 and BK20150858)the Nanjing University of Posts and Telecommunications(NUPTSF)(Nos.NY214059,NY214002,and NY215002)+2 种基金the Distinguished Professor Project of Jiangsu(No.RK002STP14001)the Six Talent Peaks Project in Jiangsu Province(No.2015-XCL-023)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Nos.SJCX17_0234 and KYCX17_0744)
文摘We experimentally obtain cylindrical vector beams（CVBs） in a passively mode-locked fiber laser based on nonlinear polarization rotation. A mode-selective coupler composed of both a single-mode fiber（SMF） and a twomode fiber（TMF） is incorporated into the cavity to act as a mode converter from LP01 mode to LP11 mode with broad spectral bandwidth. CVBs in different mode-locked states including single-pulse, multi-pulse, and bound pulse are obtained, for the first time to our best knowledge. The ultrafast CVBs with different operation states have potential applications in many fields such as laser beam machining, nanoparticle manipulation, and so on.
基金National Natural Science Foundation of China(NSFC)(10904036)Natural Science Foundation of Hunan Province(2015JJ3036)+2 种基金National High Technology Research and Development Program(2012AA01A301-01)Growth Program for Young Teachers of Hunan UniversityChina Scholarship Council(CSC)([2013]3050)
文摘The polarization evolution of vector beams(VBs) generated by q-plates is investigated theoretically and experimentally.An analytical model is developed for the VB created by a general quarter-wave q-plate based on vector diffraction theory.It is found that the polarization distribution of VBs varies with position and the value q.In particular,for the incidence of circular polarization,the exit vector vortex beam has polarization states that cover the whole surface of the Poincarésphere,thereby constituting a full Poincarébeam.For the incidence of linear polarization,the VB is not cylindrical but specularly symmetric,and exhibits an azimuthal spin splitting.These results are in sharp contrast with those derived by the commonly used model,i.e.,regarding the incident light as a plane wave.By implementing q-plates with dielectric metasurfaces,further experiments validate the theoretical results.
基金supported by the National Key Research and Development Program of China(Nos.2022YFA1404800 and 2019YFA0705000)the National Natural Science Foundation of China(Nos.11874046,12192254,92250304,11974218,11904247,12174279,12274310,and 12274311)the Local Science and Technology Development Project of the Central Government(No.YDZX20203700001766).
文摘We introduce the Stokes scintillation indices and the corresponding overall Stokes scintillations for quantitatively studying the fluctuations of both the intensity and polarization of an optical vector beam transmitting through the atmospheric turbulence.With the aid of the multiple-phase-screen method,we examine the Stokes fluctuations of a radially polarized beam in Kolmogorov turbulence numerically.The results show that the overall scintillation for the intensity distribution is always larger than the overall scintillation for the polarization-dependent Stokes parameters,which indicates that the polarization state of a vector beam is stabler than its intensity distribution in the turbulence.We interpret the results with the depolarization effect of the vector beam in turbulence.The findings in this work may be useful in free-space optical communications utilizing vector beams.
基金supported by the National Key R&D Program of China(No.2021YFC290202)the National Natural Science Foundation of China(No.51874301)the Primary Research&Development Plan of Xuzhou City(No.KC20162)。
文摘Toroidal multipole is a special current distribution that has many different characteristics from electric multipole and magnetic multipole distributions.Because of its special properties,the toroidal dipole is a research hotspot in the field of metamaterials and nanophotonics.However,the low scattering of the toroidal dipole moment makes its excitation a challenging task.At present,there are relatively few studies on its specific engineering applications.In this paper,by slotting in the rectangular cavity,the excitation of an equivalent toroidal dipole is successfully achieved over a wide frequency range of 53-58 GHz.Results indicate that under the action of the toroidal dipole,the TE_(10)mode electromagnetic waves transmitted in the rectangular waveguide are converted into vector beams and are radiated outwards.Further adjusting the spatial distribution of the magnetic dipoles in the toroidal dipoles yields results that indicate that the resonance mode in the slot is still dominated by the magnetic toroidal dipole moment,and the electromagnetic waves radiating outward are vortex beams carrying vector polarization.The scattered energy of each dipole moment inside the antenna is calculated.This calculation verifies that the mass of the vector beam and vector vortex beam is closely related to the toroidal dipole supported by this antenna.The proposed structure can be applied to explorations in vortex filtering,in photon entanglement,and in the photonic spin Hall effect.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.11974282,61675169,and 91950207)。
文摘We present the generation of the nanosecond cylindrical vector beams(CVBs)in a two-mode fiber(TMF)and its applications of stimulated Raman scattering.The nanosecond(1064 nm,10 ns,10 Hz)CVBs have been directly produced with mode conversion efficiency of~18 d B(98.4%)via an acoustically induced fiber grating,and then the stimulated Raman scattering signal is generated based on the transmission of the nanosecond CVBs in a 100-m-long TMF.The transverse mode intensity and polarization distributions of the first-order Stokes shift component(1116.8 nm)are consistent with the nanosecond CVBs pump pulse.
基金supported by the National Natural Science Foundation of China(Grant No.12274105)the Heilongjiang Natural Science Funds for Distinguished Young Scholars(Grant No.JQ2022A001)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.HIT.OCEF.2021020)the Joint Guidance Project of the Natural Science Foundation of Heilongjiang Province(Grant No.LH2023A006).
文摘Vector structured beams(VSBs)offer infinite eigenstates and open up new possibilities for highcapacity optical and quantum communications by the multiplexing of the states.Therefore,the sorting and measuring of VSBs are extremely important.However,the efficient manipulations of a large number of VSBs have simultaneously remained challenging up to now,especially in integrated optical systems.Here,we propose a compact spin-multiplexed diffractive metasurface capable of continuously sorting and detecting arbitrary VSBs through spatial intensity separation.By introducing a diffractive optical neural network with cascaded metasurface systems,we demonstrate arbitrary VSBs sorters that can simultaneously identify Laguerre–Gaussian modes(l=−4 to 4,p=1 to 4),Hermitian–Gaussian modes(m=1 to 4,n=1 to 3),and Bessel–Gaussian modes(l=1 to 12).Such a sorter for arbitrary VSBs could revolutionize applications in integrated and high-dimensional optical communication systems.
