We propose a switchable vortex beam polarization state terahertz multi-layer metasurface,which consists of threelayer elliptical metal crosses,four-layer dielectrics,and two-layer hollow metal circles,which are altern...We propose a switchable vortex beam polarization state terahertz multi-layer metasurface,which consists of threelayer elliptical metal crosses,four-layer dielectrics,and two-layer hollow metal circles,which are alternately superimposed.Under the normal incidence of left-handed circularly polarized(LCP)wave and the right-handed circularly polarized(RCP)waves,the proposed structure realizes three independent control functions,i.e.,focused and vortex beam,vortex beam with different topological charges,and polarization states switching,and azimuth switching of two vortex beams with different polarization states.The results show that the proposed metasurface provides a new idea for investigating the multifunctional terahertz wave modulation devices.展开更多
We demonstrate theoretically that the epsilon-near-zero materials can be utilized to control effectively the polarization conversion of an electromagnetic wave through reflection. The significant feature differing fro...We demonstrate theoretically that the epsilon-near-zero materials can be utilized to control effectively the polarization conversion of an electromagnetic wave through reflection. The significant feature differing from all other means based on whatever natural materials or metamaterials is that for TM incident wave, the reflected phase is a constant, while for TE wave, the reflected phase is a linear function of the incident angle. The phase difference between them covers the range from -180°to 0°, and the polarization conversions from linear states to elliptical or circular states can be obtained by only adjusting the incident angle. Because no complex structures are employed, our proposal promises a simple approach for manipulating polarization conversion at both terahertz and optical frequencies.展开更多
The state of polarization(SOP)on high-order Poincaréspheres(HOPSs),characterized by their distinctive phase profiles and polarization distributions,plays a crucial role in both classical and quantum optical appli...The state of polarization(SOP)on high-order Poincaréspheres(HOPSs),characterized by their distinctive phase profiles and polarization distributions,plays a crucial role in both classical and quantum optical applications.However,most existing metasurface-based implementations face inherent limitations:passive designs are restricted to represent a few predefined HOPS SOPs,while programmable versions typically constrain to 1-bit or 2-bit phase control resolution.In this paper,dynamic generation of HOPS beams with arbitrary SOP based on a transmissive space-time-coding metasurface is demonstrated.By combining 1-bit phase discretizations via PIN diodes with a time-coding strategy,the metasurface enables quasi-continuous complexamplitude modulation for harmonic waves in both x-and y-polarizations.Based on near-field diffraction theory,arbitrary SOPs on any HOPSm,n can be precisely generated using a linearly polarized basis,which is independently controlled by FPGA reconfiguration.We experimentally demonstrate that polarization holography on HOPS0,0 achieves high polarization purity>91.28%,and vector vortex beams on HOPS1,3 and HOPS−1,3 exhibit high orbital angular momentum mode purities>91.25%.This methodology holds great potential for structured wavefront shaping,vortex generation,and high-capacity planar photonics.展开更多
We report a new method to deeply analyze the scrambling characteristic of polarization scramblers based on density of polarization states(DPS)statistics that makes it possible to describe the DPS distribution in detai...We report a new method to deeply analyze the scrambling characteristic of polarization scramblers based on density of polarization states(DPS)statistics that makes it possible to describe the DPS distribution in detail on the whole Poincarésphere,thus easy to locate accurately the nonuniform areas of defective polarization scramblers,which cannot be realized by existing methods.We have built a polarization scrambling system to demonstrate the advantages of our method compared with others by experiments and suggested effective evaluation indexes whose validity is well confirmed by applying to a commercial scrambler.Our conclusions are valuable for accurately analyzing and diagnosing the performance of any polarization scrambler,and quality evaluation of polarization controllers or other polarization devices.展开更多
We describe a new algorithm in a cost effective polarization division multiplexing （PDM） system. Without modifying the existing transmitter, receiver electronics, or softwares, we use a special optical scheme to dem...We describe a new algorithm in a cost effective polarization division multiplexing （PDM） system. Without modifying the existing transmitter, receiver electronics, or softwares, we use a special optical scheme to demultiplex the signal multiplexed and improve it with a conjugated gradient algorithm. We experimentally resume the polarization state with a deviation under 5% and the power loss less than 20 dB which proves the feasibility of the polarization control algorithm in the new polarization multiplexing system.展开更多
We present an efficient faithful polarization entanglement distribution protocol for W state over an arbitrary noise channel,which use the frequency degree of freedom to carry the entanglement during the transmission....We present an efficient faithful polarization entanglement distribution protocol for W state over an arbitrary noise channel,which use the frequency degree of freedom to carry the entanglement during the transmission.We describe the transmission of three-photon W state as an example,and then generalize this scheme to n-qubit W state situation.The remote parties can obtain maximally entangled W states on the polarization of photons,and the success probability is 100% in principle.As there was few entanglement purification for W state,our scheme is an efficient and practical method to share W state entanglement between distant parties,which will be useful in quantum communication.We also show that our scheme can be used to distribute arbitrary multi-particle entangled state.展开更多
Reprogrammable metasurfaces,which establish a fascinating bridge between physical and information domains,can dynamically control electromagnetic(EM)waves in real time and thus have attracted great attentions from res...Reprogrammable metasurfaces,which establish a fascinating bridge between physical and information domains,can dynamically control electromagnetic(EM)waves in real time and thus have attracted great attentions from researchers around the world.To control EM waves with an arbitrary polarization state,it is desirable that a complete set of basis states be controlled independently since incident EM waves with an arbitrary polarization state can be decomposed as a linear sum of these basis states.In this work,we present the concept of complete-basis-reprogrammable coding metasurface(CBR-CM)in reflective manners,which can achieve independently dynamic controls over the reflection phases while maintaining the same amplitude for left-handed circularly polarized(LCP)waves and right-handed circularly polarized(RCP)waves.Since LCP and RCP waves together constitute a complete basis set of planar EM waves,dynamicallycontrolled holograms can be generated under arbitrarily polarized wave incidence.The dynamically reconfigurable metaparticle is implemented to demonstrate the CBR-CM’s robust capability of controlling the longitudinal and transverse positions of holograms under LCP and RCP waves independently.It’s expected that the proposed CBR-CM opens up ways of realizing more sophisticated and advanced devices with multiple independent information channels,which may provide technical assistance for digital EM environment reproduction.展开更多
The polarization properties of light are widely applied in imaging,communications,materials analy⁃sis,and life sciences.Various methods have been developed that can measure the polarization information of a target.How...The polarization properties of light are widely applied in imaging,communications,materials analy⁃sis,and life sciences.Various methods have been developed that can measure the polarization information of a target.However,conventional polarization detection systems are often bulky and complex,limiting their poten⁃tial for broader applications.To address the challenges of miniaturization,integrated polarization detectors have been extensively explored in recent years,achieving significant advancements in performance and functionality.In this review,we focus mainly on integrated polarization detectors with innovative features,including infinitely high polarization discrimination,ultrahigh sensitivity to polarization state change,full Stokes parameters measure⁃ment,and simultaneous perception of polarization and other key properties of light.Lastly,we discuss the oppor⁃tunities and challenges for the future development of integrated polarization photodetectors.展开更多
The vectorial structure of an optical field with hybrid states of polarization （SOP） in the near-field is studied by using the angular spectrum method of an electromagnetic beam. Physical images of the longitudinal ...The vectorial structure of an optical field with hybrid states of polarization （SOP） in the near-field is studied by using the angular spectrum method of an electromagnetic beam. Physical images of the longitudinal components of evanescent waves are illustrated and compared with those of the transverse components from the vectorial structure. Our results indicate that the relative weight integrated over the transverse plane of the evanescent wave depends strongly on the number of the polarization topological charges. The shapes of the intensity profiles of the longitudinal components are different from those of the transverse components, and it can be manipulated by changing the initial SoP of the field cross-section. The longitudinal component of evanescent wave dominates the near-field region. In addition, it also leads to three-dimensional shape variations of the optical field and the optical spin angular momentum flux density distributions.展开更多
Using two typical types of polarization controller, this paper analyses theoretically and experimentally the fact that it is necessary to adjust at least three instead of two waveplates in order to transform any state...Using two typical types of polarization controller, this paper analyses theoretically and experimentally the fact that it is necessary to adjust at least three instead of two waveplates in order to transform any state of polarization to any other output covering the entire Poincar6 sphere. The experimental results are exactly in accordance with the theory discussed in this paper. It has corrected the conventional and inaccurate point of view that two waveplates of a polarization controller are adequate to complete the transformation of state of polarization.展开更多
This paper reports on an experiment about a novel method of polarization stabilization. The polarization stabilizer proposed here has an additional function of polarization transformation from any state of polarizatio...This paper reports on an experiment about a novel method of polarization stabilization. The polarization stabilizer proposed here has an additional function of polarization transformation from any state of polarization into any others. The particle swarm optimization is introduced as a control algorithm in the process of either searching or endless tracking. The tracking speed of the stabilizer is obtained up to 12.6 krad/s by using hardware we have in the laboratory, which means that we can achieve a higher speed practical polarization stabilizer if we have faster hardware.展开更多
We extend the third perturbation theory to study the polarization control behavior of the intermediate state absorption in Nd^（3＋）ions. The results show that coherent interference can occur between the single-photo...We extend the third perturbation theory to study the polarization control behavior of the intermediate state absorption in Nd^（3＋）ions. The results show that coherent interference can occur between the single-photon and three-photon excitation pathways, and depends on the central frequency of the femtosecond laser field. Moreover,single-photon and three-photon absorptions have different polarization control efficiencies, and the relative weight of three-photon absorption in the whole excitation processes can increase with increasing the laser intensity.Therefore, the enhancement or suppression of the intermediate state absorption can be realized and manipulated by properly designing the intensity and central frequency of the polarization modulated femtosecond laser field.This research can not only enrich theoretical research methods for the up-conversion luminescence manipulation of rare-earth ions, but also can provide a clear physical picture for understanding and controlling multi-photon absorption in a multiple energy level system.展开更多
The evolution in momentum space of bound states in the continuum(BICs)and circularly polarized states(CPSs)—as far-field polarization singularities—can be observed by controlling the geometric parameters of photonic...The evolution in momentum space of bound states in the continuum(BICs)and circularly polarized states(CPSs)—as far-field polarization singularities—can be observed by controlling the geometric parameters of photonic crystals.This offers significant potential in optics and photonics.Here,we reveal that in complex lattices far-field polarization singularities can be flexibly manipulated while preserving structural symmetry.A change in topological charge for the at-ΓBIC can generate new BICs or CPSs.At an off-Γpoint,a BIC can spawn from the collision of two CPSs.As the thickness of the structure increases,this BIC will meet the at-ΓBIC.The merging of BICs can induce topological charge transition and yield a large wavevector space around theΓpoint with ultra-high quality(Q)factors.Our findings provide a novel degree of freedom for manipulating polarization singularities,which holds great promise in radiation modulation and singular optics.展开更多
We present an efficient faithful multipartite polarization entanglement distribution protocol over an ar- bitrary noisy channel. The spatial degree of freedom is used to carry the entanglement during the transmission....We present an efficient faithful multipartite polarization entanglement distribution protocol over an ar- bitrary noisy channel. The spatial degree of freedom is used to carry the entanglement during the transmission. We describe the principle by distributing n-qubit Greenberge-Horne--Zeilinger state and n-qubit W state. Our scheme can be used to distribute arbitrary n-qUbit entangled states to n distant locations. The remote parties can obtain maximally entangled states deterministically on the polarization of photons. Only passive linear optics are employed in our setup, which makes our scheme more feasible and efficient for practical application in long distance quantum communication.展开更多
An interpretation of the entangled states is considered.Two-photon states of photon A on path a and photon B on path b with polarizations H,V are constructed.Two synchronized photons,1 and 2,can take the paths a and b...An interpretation of the entangled states is considered.Two-photon states of photon A on path a and photon B on path b with polarizations H,V are constructed.Two synchronized photons,1 and 2,can take the paths a and b,with equal probability 50%.In the bases a,b and H,V,the states of the photons form the product states.In the basis 1,2,the states of the photons form the entangled state.The states of the photons in the bases 1,2;a,b;H,V are inseparable.The correlation of the photons due to the entanglement in the basis 1,2 can be seen in the bases a,b and H,V.The interference term in the approach under consideration and in the standard approach is the same thus providing for the same correlation.展开更多
Electrons in graphene have fourfold spin and valley degeneracies owing to the unique bipartite honeycomb lattice and an extremely weak spin-orbit coupling,which can support a series of broken symmetry states.Atomic-sc...Electrons in graphene have fourfold spin and valley degeneracies owing to the unique bipartite honeycomb lattice and an extremely weak spin-orbit coupling,which can support a series of broken symmetry states.Atomic-scale defects in graphene are expected to lift these degenerate degrees of freedom at the nanoscale,and hence,lead to rich quantum states,highlighting promising directions for spintronics and valleytronics.In this article,we mainly review the recent scanning tunneling microscopy(STM)advances on the spin and/or valley polarized states induced by an individual atomicscale defect in graphene,including a single-carbon vacancy,a nitrogen-atom dopant,and a hydrogen-atom chemisorption.Lastly,we give a perspective in this field.展开更多
Full-Stokes polarimeters can detect the polarization states of light,which is critical for the next-generation optical and optoelectronic systems.Traditional full-Stokes polarimeters are either based on bulky optical ...Full-Stokes polarimeters can detect the polarization states of light,which is critical for the next-generation optical and optoelectronic systems.Traditional full-Stokes polarimeters are either based on bulky optical systems or complex metasurface structures,which cause the system complexity with unessential energy loss.Recently,filterless on-chip full-Stokes polarimeters have been demonstrated by using optical anisotropic materials which are able to detect the circularly polarized light.Nevertheless,those on-chip full-Stokes polarimeters have either the limited detection wavelength range or relatively poor device performance that need to be further improved.Here,we report the high performance broadband full-Stokes polarimeters based on rhenium disulfide(ReS_(2)).While the anisotropic structure of the ReS_(2)introduces the in-plane optical anisotropy for linearly polarized light(LP)detection,Schottky contacts formed by the ReS_(2)-Au could break the symmetry,which can detect circularly polarized(CP)light.By building a proper model,all four Stokes parameters can be extracted by using the ReS_(2)nanobelt device.The device delivers a photoresponsivity of 181 A/W,a detectivity of 6.8×10^(10)Jones and can sense the four Stokes parameters of incident light within a wide range of wavelength from 565-800 nm with reasonable average errors.We believe our study provides an alternative strategy to develop high performance broadband on-chip full-Stokes polarimeters.展开更多
We propose a method for reconstructing the distributed forward state of polarization(SOP)in single-mode fibers(SMFs)to solve the problem of an unpredictable blind box of SOP evolution in many applications such as fibe...We propose a method for reconstructing the distributed forward state of polarization(SOP)in single-mode fibers(SMFs)to solve the problem of an unpredictable blind box of SOP evolution in many applications such as fiber-optic parametric amplification systems.Using polarization-sensitive optical frequency domain reflectometry(POFDR)and a quaternion-based model to describe polarization changes,our approach achieves high spatial resolution and precision.By an improved iterative fitting algorithm,the mean square error(MSE)of forward SOP reconstruction for approximately 100 consecutive measurement points was reduced to below 0.1%.This method enables visualization of SOP dynamics along the fiber,offering critical insights for polarization-dependent systems.展开更多
A spacecraft attitude estimation method based on electromagnetic vector sensors(EMVS)array is proposed,which employs the orthogonally constrained parallel factor(PARAFAC)algorithm and makes use of measurements of the ...A spacecraft attitude estimation method based on electromagnetic vector sensors(EMVS)array is proposed,which employs the orthogonally constrained parallel factor(PARAFAC)algorithm and makes use of measurements of the two-dimensional direction-of-arrival(2D-DOA)and polarization angles,aiming to address the issues of incomplete,asynchronous,and inaccurate third-party reference used for attitude estimation in spacecraft docking missions by employing the electromagnetic wave’s three-dimensional(3D)wave structure as a complete third-party reference.Comparative analysis with state-ofthe-art algorithms shows significant improvements in estimation accuracy and computational efficiency with this algorithm.Numerical simulations have verified the effectiveness and superiority of this method.A high-precision,reliable,and cost-effective method for rapid spacecraft attitude estimation is provided in this paper.展开更多
Polarization singularities beyond the bound states in the continuums(BICs)have garnered significant interest due to their potential for light manipulation.The conservation of topological charge has proven crucial in v...Polarization singularities beyond the bound states in the continuums(BICs)have garnered significant interest due to their potential for light manipulation.The conservation of topological charge has proven crucial in various photonic systems,and it guides the behavior of these singularities,including the generation and annihilation of BICs.This work theoretically reveals the simultaneous generation of two distinct polarization singularity types,which include off-Γaccidental BICs and Dirac-type band degeneracy points.The generation is driven by a quadratic degeneracy of symmetry-protected BICs in a photonic crystal slab.It should be noted that this is achieved through continuously tuning a geometric parameter without breaking symmetry.Importantly,the generation of both singularity types can be explained by the topological charge conservation law.This adherence ensures the stability of these singularities and allows for continuous tuning of their positions in momentum space by continuously tuning a geometric parameter while preserving symmetry.This study presents a novel framework for synthesizing and manipulating complex polarization states by combining polarization singularities from both BICs and band degeneracies and holds promise for application in other wave systems beyond photonics.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61871355,61831012,and 62271460)the Talent Project of Zhejiang Provincial Department of Science and Technology,China(Grant No.2018R52043)+1 种基金the Zhejiang Key Research and Development Project of China(Grant Nos.2021C03153 and 2022C03166)the Research Funds for the Provincial Universities of Zhejiang Province,China(Grant No.2020YW20)。
文摘We propose a switchable vortex beam polarization state terahertz multi-layer metasurface,which consists of threelayer elliptical metal crosses,four-layer dielectrics,and two-layer hollow metal circles,which are alternately superimposed.Under the normal incidence of left-handed circularly polarized(LCP)wave and the right-handed circularly polarized(RCP)waves,the proposed structure realizes three independent control functions,i.e.,focused and vortex beam,vortex beam with different topological charges,and polarization states switching,and azimuth switching of two vortex beams with different polarization states.The results show that the proposed metasurface provides a new idea for investigating the multifunctional terahertz wave modulation devices.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51406126 and 11604229
文摘We demonstrate theoretically that the epsilon-near-zero materials can be utilized to control effectively the polarization conversion of an electromagnetic wave through reflection. The significant feature differing from all other means based on whatever natural materials or metamaterials is that for TM incident wave, the reflected phase is a constant, while for TE wave, the reflected phase is a linear function of the incident angle. The phase difference between them covers the range from -180°to 0°, and the polarization conversions from linear states to elliptical or circular states can be obtained by only adjusting the incident angle. Because no complex structures are employed, our proposal promises a simple approach for manipulating polarization conversion at both terahertz and optical frequencies.
基金National Natural Science Foundation of China(62271056,62171186,62201037)Technology Innovation Center of Infrared Remote Sensing Metrology Technology of State Administration for Market Regulation(AKYKF2423)+5 种基金National Key Research and Development Program of China(2022YFF0604801)Beijing Natural Science Foundation Haidian Original Innovation Joint Fund(L222042)Open Research Fund of State Key Laboratory of Millimeter Waves(K202326)Open Research Fund of State Key Laboratory of Space-Ground Integrated Information Technology(6142221200201)Basic Research Foundation of Beijing Institute of Technology,China(BITBLR2020014)111 Project of China(B14010).
文摘The state of polarization(SOP)on high-order Poincaréspheres(HOPSs),characterized by their distinctive phase profiles and polarization distributions,plays a crucial role in both classical and quantum optical applications.However,most existing metasurface-based implementations face inherent limitations:passive designs are restricted to represent a few predefined HOPS SOPs,while programmable versions typically constrain to 1-bit or 2-bit phase control resolution.In this paper,dynamic generation of HOPS beams with arbitrary SOP based on a transmissive space-time-coding metasurface is demonstrated.By combining 1-bit phase discretizations via PIN diodes with a time-coding strategy,the metasurface enables quasi-continuous complexamplitude modulation for harmonic waves in both x-and y-polarizations.Based on near-field diffraction theory,arbitrary SOPs on any HOPSm,n can be precisely generated using a linearly polarized basis,which is independently controlled by FPGA reconfiguration.We experimentally demonstrate that polarization holography on HOPS0,0 achieves high polarization purity>91.28%,and vector vortex beams on HOPS1,3 and HOPS−1,3 exhibit high orbital angular momentum mode purities>91.25%.This methodology holds great potential for structured wavefront shaping,vortex generation,and high-capacity planar photonics.
基金This work was supported by the National Natural Science Foundation of China(Nos.11574026 and 11274037).
文摘We report a new method to deeply analyze the scrambling characteristic of polarization scramblers based on density of polarization states(DPS)statistics that makes it possible to describe the DPS distribution in detail on the whole Poincarésphere,thus easy to locate accurately the nonuniform areas of defective polarization scramblers,which cannot be realized by existing methods.We have built a polarization scrambling system to demonstrate the advantages of our method compared with others by experiments and suggested effective evaluation indexes whose validity is well confirmed by applying to a commercial scrambler.Our conclusions are valuable for accurately analyzing and diagnosing the performance of any polarization scrambler,and quality evaluation of polarization controllers or other polarization devices.
基金supported by the Key Item of Application Basis Research Plan of Tianjin under Grant No.06YFJZJC00400.
文摘We describe a new algorithm in a cost effective polarization division multiplexing （PDM） system. Without modifying the existing transmitter, receiver electronics, or softwares, we use a special optical scheme to demultiplex the signal multiplexed and improve it with a conjugated gradient algorithm. We experimentally resume the polarization state with a deviation under 5% and the power loss less than 20 dB which proves the feasibility of the polarization control algorithm in the new polarization multiplexing system.
基金Supported by the National Natural Science Foundation of China under Grant No. 11004258
文摘We present an efficient faithful polarization entanglement distribution protocol for W state over an arbitrary noise channel,which use the frequency degree of freedom to carry the entanglement during the transmission.We describe the transmission of three-photon W state as an example,and then generalize this scheme to n-qubit W state situation.The remote parties can obtain maximally entangled W states on the polarization of photons,and the success probability is 100% in principle.As there was few entanglement purification for W state,our scheme is an efficient and practical method to share W state entanglement between distant parties,which will be useful in quantum communication.We also show that our scheme can be used to distribute arbitrary multi-particle entangled state.
基金supported by the National Natural Science Foundation of China (62101588)the National Key Research and Development Program of China (SQ2022YFB3806200)+1 种基金the Young Talent Fund of Association for Science and Technology in Shaanxi (20240129)the Postdoctoral Fellowship Program of CPSF (GZC20242285)
文摘Reprogrammable metasurfaces,which establish a fascinating bridge between physical and information domains,can dynamically control electromagnetic(EM)waves in real time and thus have attracted great attentions from researchers around the world.To control EM waves with an arbitrary polarization state,it is desirable that a complete set of basis states be controlled independently since incident EM waves with an arbitrary polarization state can be decomposed as a linear sum of these basis states.In this work,we present the concept of complete-basis-reprogrammable coding metasurface(CBR-CM)in reflective manners,which can achieve independently dynamic controls over the reflection phases while maintaining the same amplitude for left-handed circularly polarized(LCP)waves and right-handed circularly polarized(RCP)waves.Since LCP and RCP waves together constitute a complete basis set of planar EM waves,dynamicallycontrolled holograms can be generated under arbitrarily polarized wave incidence.The dynamically reconfigurable metaparticle is implemented to demonstrate the CBR-CM’s robust capability of controlling the longitudinal and transverse positions of holograms under LCP and RCP waves independently.It’s expected that the proposed CBR-CM opens up ways of realizing more sophisticated and advanced devices with multiple independent information channels,which may provide technical assistance for digital EM environment reproduction.
基金Supported by the National Key Research and Development Program of China(2022YFA1404602)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0580000)+3 种基金the National Natural Science Foundation of China(U23B2045,62305362)the Program of Shanghai Academic/Technology Research Leader(22XD1424400)the Fund of SITP Innovation Foundation(CX-461 and CX-522)Special Project to Seize the Commanding Heights of Science and Technology of Chinese Academy of Sciences,subtopic(GJ0090406-6).
文摘The polarization properties of light are widely applied in imaging,communications,materials analy⁃sis,and life sciences.Various methods have been developed that can measure the polarization information of a target.However,conventional polarization detection systems are often bulky and complex,limiting their poten⁃tial for broader applications.To address the challenges of miniaturization,integrated polarization detectors have been extensively explored in recent years,achieving significant advancements in performance and functionality.In this review,we focus mainly on integrated polarization detectors with innovative features,including infinitely high polarization discrimination,ultrahigh sensitivity to polarization state change,full Stokes parameters measure⁃ment,and simultaneous perception of polarization and other key properties of light.Lastly,we discuss the oppor⁃tunities and challenges for the future development of integrated polarization photodetectors.
基金supported by the Zhejiang Provincial Natural Science Foundation,China(Grant Nos.LZ17A040001 and LY16A040014)the National Natural Science Foundation of China(Grant Nos.11574271 and 11574272)+1 种基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministrythe Science Research Foundation of Zhejiang Sci-Tech University(ZSTU),China(Grant No.14062078-Y)
文摘The vectorial structure of an optical field with hybrid states of polarization （SOP） in the near-field is studied by using the angular spectrum method of an electromagnetic beam. Physical images of the longitudinal components of evanescent waves are illustrated and compared with those of the transverse components from the vectorial structure. Our results indicate that the relative weight integrated over the transverse plane of the evanescent wave depends strongly on the number of the polarization topological charges. The shapes of the intensity profiles of the longitudinal components are different from those of the transverse components, and it can be manipulated by changing the initial SoP of the field cross-section. The longitudinal component of evanescent wave dominates the near-field region. In addition, it also leads to three-dimensional shape variations of the optical field and the optical spin angular momentum flux density distributions.
基金supported by the National Natural Science Foundation of China (Grant No 60577046)the Corporative Building Project of Beijing Educational Committee of China (Grant No XK100130737) Shandong High Technology Project of China (Grant No 2006GG2201002)
文摘Using two typical types of polarization controller, this paper analyses theoretically and experimentally the fact that it is necessary to adjust at least three instead of two waveplates in order to transform any state of polarization to any other output covering the entire Poincar6 sphere. The experimental results are exactly in accordance with the theory discussed in this paper. It has corrected the conventional and inaccurate point of view that two waveplates of a polarization controller are adequate to complete the transformation of state of polarization.
基金Project supported by the National High Technology Research and Development Program of China (Grant No. 2009AA01Z224)Huawei Technology Project,China (Grant No. YBON2008014)
文摘This paper reports on an experiment about a novel method of polarization stabilization. The polarization stabilizer proposed here has an additional function of polarization transformation from any state of polarization into any others. The particle swarm optimization is introduced as a control algorithm in the process of either searching or endless tracking. The tracking speed of the stabilizer is obtained up to 12.6 krad/s by using hardware we have in the laboratory, which means that we can achieve a higher speed practical polarization stabilizer if we have faster hardware.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51132004,11474096,11604199,U1704145 and 11747101the Science and Technology Commission of Shanghai Municipality under Grant No 14JC1401500+1 种基金the Henan Provincial Natural Science Foundation of China under Grant No 182102210117the Higher Education Key Program of He’nan Province of China under Grant Nos 17A140025 and 16A140030
文摘We extend the third perturbation theory to study the polarization control behavior of the intermediate state absorption in Nd^（3＋）ions. The results show that coherent interference can occur between the single-photon and three-photon excitation pathways, and depends on the central frequency of the femtosecond laser field. Moreover,single-photon and three-photon absorptions have different polarization control efficiencies, and the relative weight of three-photon absorption in the whole excitation processes can increase with increasing the laser intensity.Therefore, the enhancement or suppression of the intermediate state absorption can be realized and manipulated by properly designing the intensity and central frequency of the polarization modulated femtosecond laser field.This research can not only enrich theoretical research methods for the up-conversion luminescence manipulation of rare-earth ions, but also can provide a clear physical picture for understanding and controlling multi-photon absorption in a multiple energy level system.
基金Project supported by the National Natural Science Foundation of China(Grant No.12374205)。
文摘The evolution in momentum space of bound states in the continuum(BICs)and circularly polarized states(CPSs)—as far-field polarization singularities—can be observed by controlling the geometric parameters of photonic crystals.This offers significant potential in optics and photonics.Here,we reveal that in complex lattices far-field polarization singularities can be flexibly manipulated while preserving structural symmetry.A change in topological charge for the at-ΓBIC can generate new BICs or CPSs.At an off-Γpoint,a BIC can spawn from the collision of two CPSs.As the thickness of the structure increases,this BIC will meet the at-ΓBIC.The merging of BICs can induce topological charge transition and yield a large wavevector space around theΓpoint with ultra-high quality(Q)factors.Our findings provide a novel degree of freedom for manipulating polarization singularities,which holds great promise in radiation modulation and singular optics.
基金Supported by the National Natural Science Foundation of China under Grant No.11004258Fundamental Research Funds for the Central Universities under Grant No.CQDXWL-2012-014
文摘We present an efficient faithful multipartite polarization entanglement distribution protocol over an ar- bitrary noisy channel. The spatial degree of freedom is used to carry the entanglement during the transmission. We describe the principle by distributing n-qubit Greenberge-Horne--Zeilinger state and n-qubit W state. Our scheme can be used to distribute arbitrary n-qUbit entangled states to n distant locations. The remote parties can obtain maximally entangled states deterministically on the polarization of photons. Only passive linear optics are employed in our setup, which makes our scheme more feasible and efficient for practical application in long distance quantum communication.
文摘An interpretation of the entangled states is considered.Two-photon states of photon A on path a and photon B on path b with polarizations H,V are constructed.Two synchronized photons,1 and 2,can take the paths a and b,with equal probability 50%.In the bases a,b and H,V,the states of the photons form the product states.In the basis 1,2,the states of the photons form the entangled state.The states of the photons in the bases 1,2;a,b;H,V are inseparable.The correlation of the photons due to the entanglement in the basis 1,2 can be seen in the bases a,b and H,V.The interference term in the approach under consideration and in the standard approach is the same thus providing for the same correlation.
基金financial supported by the National Natural Science Foundation of China(Grant Nos.92163206 and 61725107)the National Key Research and Development Program of China(Grant No.2020YFA0308800)+1 种基金Beijing Natural Science Foundation(Grant No.Z190006)China Postdoctoral Science Foundation(Grant No.2021M700407)。
文摘Electrons in graphene have fourfold spin and valley degeneracies owing to the unique bipartite honeycomb lattice and an extremely weak spin-orbit coupling,which can support a series of broken symmetry states.Atomic-scale defects in graphene are expected to lift these degenerate degrees of freedom at the nanoscale,and hence,lead to rich quantum states,highlighting promising directions for spintronics and valleytronics.In this article,we mainly review the recent scanning tunneling microscopy(STM)advances on the spin and/or valley polarized states induced by an individual atomicscale defect in graphene,including a single-carbon vacancy,a nitrogen-atom dopant,and a hydrogen-atom chemisorption.Lastly,we give a perspective in this field.
基金the support from the National Key Research and Development Program of China(2022YFB2803900 and 2018YFA0704403)NSFC(62074064)。
文摘Full-Stokes polarimeters can detect the polarization states of light,which is critical for the next-generation optical and optoelectronic systems.Traditional full-Stokes polarimeters are either based on bulky optical systems or complex metasurface structures,which cause the system complexity with unessential energy loss.Recently,filterless on-chip full-Stokes polarimeters have been demonstrated by using optical anisotropic materials which are able to detect the circularly polarized light.Nevertheless,those on-chip full-Stokes polarimeters have either the limited detection wavelength range or relatively poor device performance that need to be further improved.Here,we report the high performance broadband full-Stokes polarimeters based on rhenium disulfide(ReS_(2)).While the anisotropic structure of the ReS_(2)introduces the in-plane optical anisotropy for linearly polarized light(LP)detection,Schottky contacts formed by the ReS_(2)-Au could break the symmetry,which can detect circularly polarized(CP)light.By building a proper model,all four Stokes parameters can be extracted by using the ReS_(2)nanobelt device.The device delivers a photoresponsivity of 181 A/W,a detectivity of 6.8×10^(10)Jones and can sense the four Stokes parameters of incident light within a wide range of wavelength from 565-800 nm with reasonable average errors.We believe our study provides an alternative strategy to develop high performance broadband on-chip full-Stokes polarimeters.
基金supported by the National Key R&D Program of China(No.2023YFB2804900)the National Natural Science Foundation of China(Nos.62275151 and 62405178)。
文摘We propose a method for reconstructing the distributed forward state of polarization(SOP)in single-mode fibers(SMFs)to solve the problem of an unpredictable blind box of SOP evolution in many applications such as fiber-optic parametric amplification systems.Using polarization-sensitive optical frequency domain reflectometry(POFDR)and a quaternion-based model to describe polarization changes,our approach achieves high spatial resolution and precision.By an improved iterative fitting algorithm,the mean square error(MSE)of forward SOP reconstruction for approximately 100 consecutive measurement points was reduced to below 0.1%.This method enables visualization of SOP dynamics along the fiber,offering critical insights for polarization-dependent systems.
文摘A spacecraft attitude estimation method based on electromagnetic vector sensors(EMVS)array is proposed,which employs the orthogonally constrained parallel factor(PARAFAC)algorithm and makes use of measurements of the two-dimensional direction-of-arrival(2D-DOA)and polarization angles,aiming to address the issues of incomplete,asynchronous,and inaccurate third-party reference used for attitude estimation in spacecraft docking missions by employing the electromagnetic wave’s three-dimensional(3D)wave structure as a complete third-party reference.Comparative analysis with state-ofthe-art algorithms shows significant improvements in estimation accuracy and computational efficiency with this algorithm.Numerical simulations have verified the effectiveness and superiority of this method.A high-precision,reliable,and cost-effective method for rapid spacecraft attitude estimation is provided in this paper.
基金supported by the National Natural Science Foundation of China(Nos.11974259 and 12274241)。
文摘Polarization singularities beyond the bound states in the continuums(BICs)have garnered significant interest due to their potential for light manipulation.The conservation of topological charge has proven crucial in various photonic systems,and it guides the behavior of these singularities,including the generation and annihilation of BICs.This work theoretically reveals the simultaneous generation of two distinct polarization singularity types,which include off-Γaccidental BICs and Dirac-type band degeneracy points.The generation is driven by a quadratic degeneracy of symmetry-protected BICs in a photonic crystal slab.It should be noted that this is achieved through continuously tuning a geometric parameter without breaking symmetry.Importantly,the generation of both singularity types can be explained by the topological charge conservation law.This adherence ensures the stability of these singularities and allows for continuous tuning of their positions in momentum space by continuously tuning a geometric parameter while preserving symmetry.This study presents a novel framework for synthesizing and manipulating complex polarization states by combining polarization singularities from both BICs and band degeneracies and holds promise for application in other wave systems beyond photonics.
