Polar semiconductors,particularly the emerging polar two-dimensional(2D)halide perovskites,have motivated immense interest in diverse photoelectronic devices due to their distinguishing polarizationgenerated photoelec...Polar semiconductors,particularly the emerging polar two-dimensional(2D)halide perovskites,have motivated immense interest in diverse photoelectronic devices due to their distinguishing polarizationgenerated photoelectric effects.However,the constraints on the organic cation's choice are still subject to limitations of polar 2D halide perovskites due to the size of the inorganic pocket between adjacent corner-sharing octahedra.Herein,a mixed spacer cation ordering strategy is employed to assemble a polar 2D halide perovskite NMAMAPb Br_(4)(NMPB,NMA is N-methylbenzene ammonium,MA is methylammonium)with alternating cation in the interlayer space.Driven by the incorporation of a second MA cation,the perovskite layer transformed from a 2D Pb_(7)Br_(24)anionic network with corner-and face-sharing octahedra to a flat 2D PbBr_(4)perovskite networks only with corner-sharing octahedra.In the crystal structure of NMPB,the asymmetric hydrogen-bonding interactions between ordered mixed-spacer cations and 2D perovskite layers give rise to a second harmonic generation response and a large polarization of 1.3μC/cm^(2).More intriguingly,the ordered 2D perovskite networks endow NMPB with excellent self-powered polarization-sensitive detection performance,showing a considerable polarization-related dichroism ratio up to 1.87.The reconstruction of an inorganic framework within a crystal through mixed cation ordering offers a new synthetic tool for templating perovskite lattices with controlled properties,overcoming limitations of conventional cation choice.展开更多
Perpendicular optical reversal of the linear dichroism transition has promising applications in polarization-sensitive optoelectronic devices. We perform a systematical study on the in-plane optical anisotropy of quas...Perpendicular optical reversal of the linear dichroism transition has promising applications in polarization-sensitive optoelectronic devices. We perform a systematical study on the in-plane optical anisotropy of quasi-one-dimensional PdBr_(2) by using combined measurements of the angle-resolved polarized Raman spectroscopy(ARPRS) and anisotropic optical absorption spectrum. The analyses of ARPRS data validate the anisotropic Raman properties of the PdBr_(2) flake.And anisotropic optical absorption spectrum of PdBr_(2) nanoflake demonstrates distinct optical linear dichroism reversal. Photodetector constructed by PdBr_(2) nanowire exhibits high responsivity of 747 A·W^(-1) and specific detectivity of 5.8×10^(12) Jones. And the photodetector demonstrates prominent polarization-sensitive photoresponsivity under 405-nm light irradiation with large photocurrent anisotropy ratio of 1.56, which is superior to those of most of previously reported quasi-one-dimensional counterparts. Our study offers fundamental insights into the strong optical anisotropy exhibited by PdBr_(2), establishing it as a promising candidate for miniaturization and integration trends of polarization-related applications.展开更多
The received signal of the polarization sensitive array is proved to have trilinear model characteristics. The blind parallel factor（PARAFAC） signal detection algorithm for the polarization sensitive array is propos...The received signal of the polarization sensitive array is proved to have trilinear model characteristics. The blind parallel factor（PARAFAC） signal detection algorithm for the polarization sensitive array is proposed. The trilinear alternating least square （TALS） algorithm is used to abtain the source matrix, and then the matrix is judged. Simulation results show that the bit error rate （BER） of the detection algorithm is close to that of the non-blind decorrelating method and the algorithm works well under the array error condition. BER difference between the non-blind method and this algorithm is less than 2 dB under a high SNR. The algorithm is blind and robust. The channel fading, the direction of arrive（DOA） imformation and the polarization information are needless in the algorithm.展开更多
This paper addresses the problem of direction-of-arrival （DOA） and polarization estima- tion with polarization sensitive arrays （PSA）, which has been a hot topic in the area of array signal processing during the p...This paper addresses the problem of direction-of-arrival （DOA） and polarization estima- tion with polarization sensitive arrays （PSA）, which has been a hot topic in the area of array signal processing during the past two or three decades. The sparse Bayesian learning （SBL） technique is introduced to exploit the sparsity of the incident signals in space to solve this problem and a new method is proposed by reconstructing the signals from the array outputs first and then exploit- ing the reconstructed signals to realize parameter estimation. Only 1-D searching and numerical calculations are contained in the proposed method, which makes the proposed method computa- tionally much efficient. Based on a linear array consisting of identically structured sensors, the proposed method can be used with slight modifications in PSA with different polarization structures. It also performs well in the presence of coherent signals or signals with different degrees of polarization. Simulation results are given to demonstrate the parameter estimation precision of the proposed method.展开更多
The problem of joint direction of arrival(DOA)and polarization estimation for polarization sensitive coprime planar arrays(PS-CPAs)is investigated,and a fast-convergence quadrilinear decomposition approach is proposed...The problem of joint direction of arrival(DOA)and polarization estimation for polarization sensitive coprime planar arrays(PS-CPAs)is investigated,and a fast-convergence quadrilinear decomposition approach is proposed.Specifically,we first decompose the PS-CPA into two sparse polarization sensitive uniform planar subarrays and employ propagator method(PM)to construct the initial steering matrices separately.Then we arrange the received signals into two quadrilinear models so that the potential DOA and polarization estimates can be attained via quadrilinear alternating least square(QALS).Subsequently,we distinguish the true DOA estimates from the approximate intersecting estimations of the two subarrays in view of the coprime feature.Finally,the polarization estimates paired with DOA can be obtained.In contrast to the conventional QALS algorithm,the proposed approach can remarkably reduce the computational complexity without degrading the estimation performance.Simulations demonstrate the superiority of the proposed fast-convergence approach for PS-CPAs.展开更多
A novel D–π –A structure and near–infrared fluorescent probe(DCITT) with high polarity sensitivity and membrane targeting was reported. The fluorescent spectra of DCITT were polarity dependent and Stokes shift was...A novel D–π –A structure and near–infrared fluorescent probe(DCITT) with high polarity sensitivity and membrane targeting was reported. The fluorescent spectra of DCITT were polarity dependent and Stokes shift was greater than 300 nm. Due to its high fluorescence quantum yield, low cytotoxicity and photostability, DCITT could be used as a labeling probe in multicellular organisms. In particular, DCITT effectively distinguished tumor cells from normal cells because it could specifically light up the cancer cells membrane based on strong red fluorescence for a long time. On this basis, a polar–sensitive cell membrane probe is developed to differentiate tumor cells from normal cells, which provides an idea and method for the early diagnosis of tumor at cellular level.展开更多
Polarization is an important attribute of light and can be artificially modulated as a versatile information carrier.Conventional polarization-sensitive photodetection relies on a combination of polarizing optical ele...Polarization is an important attribute of light and can be artificially modulated as a versatile information carrier.Conventional polarization-sensitive photodetection relies on a combination of polarizing optical elements and standard photodetectors,which requires a substantial amount of space and manufacturing expenses.Although onchip polarized photodetectors have been realized in recent years based on two-dimensional(2D)materials with lowsymmetry crystal structures,they are limited by the intrinsic anisotropic property and thus the optional range of materials,the operation wavelength,and more importantly,the low anisotropic ratio,hindering their practical applications.In this work,we construct a versatile platform that transcends the constraints of material anisotropy,by integrating WSe2-based photodetector with MoS2-based field-effect transistor,delivering high-performance broadband polarization detection capability with orders of magnitude improvement in anisotropic ratio and on/off ratio.The polarization arises from hot electron injection caused by the plasmonic metal electrode and is amplified by the transistor to raise the anisotropic ratio from 2 to an impressive value over 60 in the infrared(iR)band,reaching the level of existing applications.Meanwhile,the system achieves a significant improvement in photosensitivity,with an on/off ratio of over 1o3 in the IR band.Based on the above performance optimization,we demonstrated its polarization-modulated IR optical communication ability and polarized artificial vision applications with a high image recognition accuracy of~99%.The proposed platform provides a promising route for the development of the longsought minimized,high-performance,multifunctional optoelectronic systems.展开更多
This study pioneers a high-performance UV polarization-sensitive photodetector by ingeniously integrating noncentrosymmetric metal nanostructures into a graphene(Gr)/Al_(2)O_(3)/GaN heterojunction.Unlike conventional ...This study pioneers a high-performance UV polarization-sensitive photodetector by ingeniously integrating noncentrosymmetric metal nanostructures into a graphene(Gr)/Al_(2)O_(3)/GaN heterojunction.Unlike conventional approaches constrained by graphene's intrinsic isotropy or complex nanoscale patterning,our design introduces asymmetric metal architectures(E-/T-type) to artificially create directional anisotropy.These structures generate plasmon-enhanced localized electric fields that selectively amplify photogenerated carrier momentum under polarized UV light(325 nm),synergized with Fowler-Nordheim tunneling(FNT) across an atomically thin Al_(2)O_(3) barrier.The result is a breakthrough in performance:a record anisotropy ratio of 115.5(E-type,-2 V) and exceptional responsivity(97.7 A/W),surpassing existing graphene-based detectors by over an order of magnitude.Crucially,by systematically modulating metal geometry and density,we demonstrate a universal platform adaptable to diverse 2D/3D systems.This study provides a valuable reference for developing and practically applying photodetectors with higher anisotropy than ultraviolet polarization sensitivity.展开更多
In this work,we demonstrate a single-photon lidar based on a polarization suppression underwater backscatter method.The system adds polarization modules at the transmitter and receiver,which increases the full width a...In this work,we demonstrate a single-photon lidar based on a polarization suppression underwater backscatter method.The system adds polarization modules at the transmitter and receiver,which increases the full width at half-maximum of the system response function by about 5 times,improving the signal-to-background ratio,ranging accuracy,and imaging effect.Meanwhile,we optimize a sparsity adaptive matching pursuit algorithm that achieves the reconstruction of target images with a 7.3 attenuation length between the system and the target.The depth resolution of the system under different scattering conditions is studied.This work provides a new method for underwater imaging.展开更多
This paper proposes a new algorithm for joint frequency, two-dimensional （2-D） directions-of-arrival （DOA）, and polarization estimation using parallel factor （PARAFAC） analysis model and cumulant. The proposed a...This paper proposes a new algorithm for joint frequency, two-dimensional （2-D） directions-of-arrival （DOA）, and polarization estimation using parallel factor （PARAFAC） analysis model and cumulant. The proposed algorithm designs a new array configuration, and extends the PARAFAC analysis model from the common data-domain and subspace-domain to the cumulant one, and forms three-way arrays by using the three cumulant matrices obtained from the properly chosen dipole outputs, and analyzes the uniqueness of low-rank decomposition of the three-way arrays, and then jointly estimates the source parameters via the low-rank decomposition of the constructed PARAFAC model. In comparison with the conventional methods, the proposed method alleviates the aperture loss, and avoids pairing parameter. Finally, the simulation results are presented to validate the performance of the proposed method.展开更多
We propose and analyze a silicon hybrid plasmonic polarization splitter-rotator with an ultra-short footprint using an asymmetric bent directional coupler on a silicon-on-insulator platform.Benefitting from the large ...We propose and analyze a silicon hybrid plasmonic polarization splitter-rotator with an ultra-short footprint using an asymmetric bent directional coupler on a silicon-on-insulator platform.Benefitting from the large birefringence induced by the bent structure and plasmonic effect,the cross-polarization coupling length is only 5.21μm.The transverse magnetic to transverse electric polarization conversion efficiency is over 99.9%,with an extinction ratio of 20.6 dB(32.5 dB)for the transverse magnetic(transverse electric)mode at 1.55μm.Furthermore,the polarization conversion efficiency is higher than 90%while maintaining cross talk below-19 dB within the bandwidth of 80 nm.展开更多
Background:The retina has been used to study the pathophysiology of multiple sclerosis(MS).Peripapillary retinal nerve fiber layer(pRNFL)thinning has been suggested as an ocular biomarker of neurodegeneration in MS.Th...Background:The retina has been used to study the pathophysiology of multiple sclerosis(MS).Peripapillary retinal nerve fiber layer(pRNFL)thinning has been suggested as an ocular biomarker of neurodegeneration in MS.The goal of this project was to determine the birefringence of the pRNFL by measuring the fiber birefringence using polarization sensitive optical coherence tomography(PS-OCT).Methods:Sixty-six MS patients without history of optic neuritis(age:39.9±11.0 yrs.old,53 females and 13 males)and 66 age-and gender-matched normal controls(age:40.7±11.4 yrs.old)were recruited.Custom built PS-OCT was used to measure phase retardation per unit depth(PR/UD,proportional to the birefringence)and pRNFL thickness in each quadrant of the pRNFL.In addition,clinical manifestation was used to correlate with the pRNFL birefringence.Results:The pRNFL was thinner in the temporal and inferior quadrants in MS patients compared with normal controls(P<0.05).The PR/UD of the pRNFL was significantly decreased in MS patients(P<0.05)in all quadrants except for the nasal quadrant.In both groups,the PR/UD from all four quadrants was not related to the averaged pRNFL thickness(P>0.05).In MS patients,the PR/UD was not related to the expanded disability status scale(EDSS)nor disease duration(r ranged from−0.17 to 0.02,P>0.05).Conclusion:This is the first study using PS-OCT to study the pRNFL birefringence in MS patients.Decreased birefringence of the pRNFL may indicate microtubule abnormality,and could be a potential biomarker for detecting early neurodegeneration in MS.展开更多
In this paper, new Cramér-Rao lower bounds （CRB） of the estimates of frequencies, two-dimensional arrival angles and polarization parameters of multiple incident signals are derived for a polarization sensitive...In this paper, new Cramér-Rao lower bounds （CRB） of the estimates of frequencies, two-dimensional arrival angles and polarization parameters of multiple incident signals are derived for a polarization sensitive array. The incident sources have distinct carrier-frequencies, in contrast to the modeling of all sources to be at the same known carrier-frequency, which has been investigated in the existing research literature on the Cramér-Rao bounds （CRB） for polarization sensitive direction finding. The derived CRBs are compact closed-form expressions and applicable to an arbitrary array geometry. Numerical examples and analysis of some special cases provide insights into the fact that the estimation accuracy of all parameters is enhanced with the increasing signal-to-noise ratio （SNR） and number of snapshots. In addition, they are hardly influenced by the sampling frequency and independent of the initial phase of incident sources. These insights offer guidelines to the system engineer on how to improve parameters＇ estimation accuracy.展开更多
InP technology is the principal enabler for implementing fully monolithic photonic integrated circuits(PIC),uniquely including transmitter elements.In this article we present an overview of recent achievements on ultr...InP technology is the principal enabler for implementing fully monolithic photonic integrated circuits(PIC),uniquely including transmitter elements.In this article we present an overview of recent achievements on ultra-high speed electro-absorption modulated lasers(EML)which represent a simple transmitter PIC comprising a singlemode laser diode and an electro-absorption modulator.Using a so-called identicallayer approach single-wavelength modulation rates up to 100 Gb/s have been accomplished.By additionally integrating an optical amplifier section modulated optical output power of>10 dBm has been achieved.Multi-level amplitude modulation was successfully demonstrated.Extended EML chips designed for wavelength-division and space-division multiplexing,respectively,will be presented.For dual-polarization transmission a novel EML related transmitter as well as a corresponding receiver PIC have been introduced.The latter devices were made on a generic PIC platform that is available for open-access foundry service.展开更多
The polarization sensitive CARS (coherent anti stokes Raman spectroscopy) method is used for the direct spectroscopic investigating of the vibration of double bonds in nucleiosides. The nonresonant background in CAR...The polarization sensitive CARS (coherent anti stokes Raman spectroscopy) method is used for the direct spectroscopic investigating of the vibration of double bonds in nucleiosides. The nonresonant background in CARS has been effectively suppressed and the vibration mode of these double bonds can be clearly resolved. The spectral features are discussed in terms of the characteristic group frequency and analogies with spectra of molecules with related structures. These spectral feature may be of use for studying biomolecules of unknown composition.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22193042,22125110,22075285,52473283,21921001,U21A2069)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(No.ZDBS-LY-SLH024)the Youth Innovation Promotion of Chinese Academy of Sciences(No.2020307)。
文摘Polar semiconductors,particularly the emerging polar two-dimensional(2D)halide perovskites,have motivated immense interest in diverse photoelectronic devices due to their distinguishing polarizationgenerated photoelectric effects.However,the constraints on the organic cation's choice are still subject to limitations of polar 2D halide perovskites due to the size of the inorganic pocket between adjacent corner-sharing octahedra.Herein,a mixed spacer cation ordering strategy is employed to assemble a polar 2D halide perovskite NMAMAPb Br_(4)(NMPB,NMA is N-methylbenzene ammonium,MA is methylammonium)with alternating cation in the interlayer space.Driven by the incorporation of a second MA cation,the perovskite layer transformed from a 2D Pb_(7)Br_(24)anionic network with corner-and face-sharing octahedra to a flat 2D PbBr_(4)perovskite networks only with corner-sharing octahedra.In the crystal structure of NMPB,the asymmetric hydrogen-bonding interactions between ordered mixed-spacer cations and 2D perovskite layers give rise to a second harmonic generation response and a large polarization of 1.3μC/cm^(2).More intriguingly,the ordered 2D perovskite networks endow NMPB with excellent self-powered polarization-sensitive detection performance,showing a considerable polarization-related dichroism ratio up to 1.87.The reconstruction of an inorganic framework within a crystal through mixed cation ordering offers a new synthetic tool for templating perovskite lattices with controlled properties,overcoming limitations of conventional cation choice.
基金Project supported by the National Key Research and Development Program of China (Grant Nos. 2022YFA1403203 and 2021YFA1600201)the National Natural Science Foundation of China (Grant No. 12274414)the Basic Research Program of the Chinese Academy of Sciences Based on Major Scientific Infrastructures (Contract No. JZHKYPT-2021-08)。
文摘Perpendicular optical reversal of the linear dichroism transition has promising applications in polarization-sensitive optoelectronic devices. We perform a systematical study on the in-plane optical anisotropy of quasi-one-dimensional PdBr_(2) by using combined measurements of the angle-resolved polarized Raman spectroscopy(ARPRS) and anisotropic optical absorption spectrum. The analyses of ARPRS data validate the anisotropic Raman properties of the PdBr_(2) flake.And anisotropic optical absorption spectrum of PdBr_(2) nanoflake demonstrates distinct optical linear dichroism reversal. Photodetector constructed by PdBr_(2) nanowire exhibits high responsivity of 747 A·W^(-1) and specific detectivity of 5.8×10^(12) Jones. And the photodetector demonstrates prominent polarization-sensitive photoresponsivity under 405-nm light irradiation with large photocurrent anisotropy ratio of 1.56, which is superior to those of most of previously reported quasi-one-dimensional counterparts. Our study offers fundamental insights into the strong optical anisotropy exhibited by PdBr_(2), establishing it as a promising candidate for miniaturization and integration trends of polarization-related applications.
文摘The received signal of the polarization sensitive array is proved to have trilinear model characteristics. The blind parallel factor（PARAFAC） signal detection algorithm for the polarization sensitive array is proposed. The trilinear alternating least square （TALS） algorithm is used to abtain the source matrix, and then the matrix is judged. Simulation results show that the bit error rate （BER） of the detection algorithm is close to that of the non-blind decorrelating method and the algorithm works well under the array error condition. BER difference between the non-blind method and this algorithm is less than 2 dB under a high SNR. The algorithm is blind and robust. The channel fading, the direction of arrive（DOA） imformation and the polarization information are needless in the algorithm.
基金co-supported by the National Natural Science Foundation of China(No.61302141)the Special Fund for Doctoral Subjects in Higher Education Institutions of China(No.20134307120023)
文摘This paper addresses the problem of direction-of-arrival （DOA） and polarization estima- tion with polarization sensitive arrays （PSA）, which has been a hot topic in the area of array signal processing during the past two or three decades. The sparse Bayesian learning （SBL） technique is introduced to exploit the sparsity of the incident signals in space to solve this problem and a new method is proposed by reconstructing the signals from the array outputs first and then exploit- ing the reconstructed signals to realize parameter estimation. Only 1-D searching and numerical calculations are contained in the proposed method, which makes the proposed method computa- tionally much efficient. Based on a linear array consisting of identically structured sensors, the proposed method can be used with slight modifications in PSA with different polarization structures. It also performs well in the presence of coherent signals or signals with different degrees of polarization. Simulation results are given to demonstrate the parameter estimation precision of the proposed method.
基金supported by the Open Research Fund of the State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System(No.CEMEE2019Z0104B)。
文摘The problem of joint direction of arrival(DOA)and polarization estimation for polarization sensitive coprime planar arrays(PS-CPAs)is investigated,and a fast-convergence quadrilinear decomposition approach is proposed.Specifically,we first decompose the PS-CPA into two sparse polarization sensitive uniform planar subarrays and employ propagator method(PM)to construct the initial steering matrices separately.Then we arrange the received signals into two quadrilinear models so that the potential DOA and polarization estimates can be attained via quadrilinear alternating least square(QALS).Subsequently,we distinguish the true DOA estimates from the approximate intersecting estimations of the two subarrays in view of the coprime feature.Finally,the polarization estimates paired with DOA can be obtained.In contrast to the conventional QALS algorithm,the proposed approach can remarkably reduce the computational complexity without degrading the estimation performance.Simulations demonstrate the superiority of the proposed fast-convergence approach for PS-CPAs.
基金Henan Provincial Science and Technology Research Project (No.232102310369) for financial support。
文摘A novel D–π –A structure and near–infrared fluorescent probe(DCITT) with high polarity sensitivity and membrane targeting was reported. The fluorescent spectra of DCITT were polarity dependent and Stokes shift was greater than 300 nm. Due to its high fluorescence quantum yield, low cytotoxicity and photostability, DCITT could be used as a labeling probe in multicellular organisms. In particular, DCITT effectively distinguished tumor cells from normal cells because it could specifically light up the cancer cells membrane based on strong red fluorescence for a long time. On this basis, a polar–sensitive cell membrane probe is developed to differentiate tumor cells from normal cells, which provides an idea and method for the early diagnosis of tumor at cellular level.
基金support of the National Natural Science Foundation of China(Nos.62334010,62121005,and 62304221)the National Key Researchand Development Program(2021YFA0717600)the International Fund Program of Changchun Institute of Optics,Fine Mechanics andPhysics,ChineseAcademyofSciences.
文摘Polarization is an important attribute of light and can be artificially modulated as a versatile information carrier.Conventional polarization-sensitive photodetection relies on a combination of polarizing optical elements and standard photodetectors,which requires a substantial amount of space and manufacturing expenses.Although onchip polarized photodetectors have been realized in recent years based on two-dimensional(2D)materials with lowsymmetry crystal structures,they are limited by the intrinsic anisotropic property and thus the optional range of materials,the operation wavelength,and more importantly,the low anisotropic ratio,hindering their practical applications.In this work,we construct a versatile platform that transcends the constraints of material anisotropy,by integrating WSe2-based photodetector with MoS2-based field-effect transistor,delivering high-performance broadband polarization detection capability with orders of magnitude improvement in anisotropic ratio and on/off ratio.The polarization arises from hot electron injection caused by the plasmonic metal electrode and is amplified by the transistor to raise the anisotropic ratio from 2 to an impressive value over 60 in the infrared(iR)band,reaching the level of existing applications.Meanwhile,the system achieves a significant improvement in photosensitivity,with an on/off ratio of over 1o3 in the IR band.Based on the above performance optimization,we demonstrated its polarization-modulated IR optical communication ability and polarized artificial vision applications with a high image recognition accuracy of~99%.The proposed platform provides a promising route for the development of the longsought minimized,high-performance,multifunctional optoelectronic systems.
基金National Natural Science Foundation of China(62375090, 62374062, 52002135)Natural Science Foundation of Guangdong Province of China(2023B1515120071)+2 种基金Science and Technology Program of Guangdong Province of China (2023A0505050131,2022A0505050066, 2024A1515011081)Characteristic Innovation Project of Universities in Guangdong Province(2023KTSCX028)Science and Technology Program of Guangzhou,China (2024A04J6456)
文摘This study pioneers a high-performance UV polarization-sensitive photodetector by ingeniously integrating noncentrosymmetric metal nanostructures into a graphene(Gr)/Al_(2)O_(3)/GaN heterojunction.Unlike conventional approaches constrained by graphene's intrinsic isotropy or complex nanoscale patterning,our design introduces asymmetric metal architectures(E-/T-type) to artificially create directional anisotropy.These structures generate plasmon-enhanced localized electric fields that selectively amplify photogenerated carrier momentum under polarized UV light(325 nm),synergized with Fowler-Nordheim tunneling(FNT) across an atomically thin Al_(2)O_(3) barrier.The result is a breakthrough in performance:a record anisotropy ratio of 115.5(E-type,-2 V) and exceptional responsivity(97.7 A/W),surpassing existing graphene-based detectors by over an order of magnitude.Crucially,by systematically modulating metal geometry and density,we demonstrate a universal platform adaptable to diverse 2D/3D systems.This study provides a valuable reference for developing and practically applying photodetectors with higher anisotropy than ultraviolet polarization sensitivity.
基金supported by the Technology Plan Project of State Administration for Market Regulation(No.2022MK218)the National Key Research and Development Program of China(No.2023YFE0207700)the Research Funding Project of Zhejiang Provincial Department of Education(No.Y202249439)。
文摘In this work,we demonstrate a single-photon lidar based on a polarization suppression underwater backscatter method.The system adds polarization modules at the transmitter and receiver,which increases the full width at half-maximum of the system response function by about 5 times,improving the signal-to-background ratio,ranging accuracy,and imaging effect.Meanwhile,we optimize a sparsity adaptive matching pursuit algorithm that achieves the reconstruction of target images with a 7.3 attenuation length between the system and the target.The depth resolution of the system under different scattering conditions is studied.This work provides a new method for underwater imaging.
基金Supported by the National Natural Science Foundation of China (Grant No. 60901059/F0103)the Educational Department Foundations of Shaanxi Province (Grant No. 09JK629)the Doctor Research Start Fund of Xi’an University of Technology (Grant No. 116-210903)
文摘This paper proposes a new algorithm for joint frequency, two-dimensional （2-D） directions-of-arrival （DOA）, and polarization estimation using parallel factor （PARAFAC） analysis model and cumulant. The proposed algorithm designs a new array configuration, and extends the PARAFAC analysis model from the common data-domain and subspace-domain to the cumulant one, and forms three-way arrays by using the three cumulant matrices obtained from the properly chosen dipole outputs, and analyzes the uniqueness of low-rank decomposition of the three-way arrays, and then jointly estimates the source parameters via the low-rank decomposition of the constructed PARAFAC model. In comparison with the conventional methods, the proposed method alleviates the aperture loss, and avoids pairing parameter. Finally, the simulation results are presented to validate the performance of the proposed method.
基金partially supported by the National Natural Science Foundation of China(NSFC)(Nos.61827817 and 61525501)。
文摘We propose and analyze a silicon hybrid plasmonic polarization splitter-rotator with an ultra-short footprint using an asymmetric bent directional coupler on a silicon-on-insulator platform.Benefitting from the large birefringence induced by the bent structure and plasmonic effect,the cross-polarization coupling length is only 5.21μm.The transverse magnetic to transverse electric polarization conversion efficiency is over 99.9%,with an extinction ratio of 20.6 dB(32.5 dB)for the transverse magnetic(transverse electric)mode at 1.55μm.Furthermore,the polarization conversion efficiency is higher than 90%while maintaining cross talk below-19 dB within the bandwidth of 80 nm.
基金Supported by the National Multiple Sclerosis Society,NIH Center Grant P30 EY014801a grant from Research to Prevent Blindness(RPB).
文摘Background:The retina has been used to study the pathophysiology of multiple sclerosis(MS).Peripapillary retinal nerve fiber layer(pRNFL)thinning has been suggested as an ocular biomarker of neurodegeneration in MS.The goal of this project was to determine the birefringence of the pRNFL by measuring the fiber birefringence using polarization sensitive optical coherence tomography(PS-OCT).Methods:Sixty-six MS patients without history of optic neuritis(age:39.9±11.0 yrs.old,53 females and 13 males)and 66 age-and gender-matched normal controls(age:40.7±11.4 yrs.old)were recruited.Custom built PS-OCT was used to measure phase retardation per unit depth(PR/UD,proportional to the birefringence)and pRNFL thickness in each quadrant of the pRNFL.In addition,clinical manifestation was used to correlate with the pRNFL birefringence.Results:The pRNFL was thinner in the temporal and inferior quadrants in MS patients compared with normal controls(P<0.05).The PR/UD of the pRNFL was significantly decreased in MS patients(P<0.05)in all quadrants except for the nasal quadrant.In both groups,the PR/UD from all four quadrants was not related to the averaged pRNFL thickness(P>0.05).In MS patients,the PR/UD was not related to the expanded disability status scale(EDSS)nor disease duration(r ranged from−0.17 to 0.02,P>0.05).Conclusion:This is the first study using PS-OCT to study the pRNFL birefringence in MS patients.Decreased birefringence of the pRNFL may indicate microtubule abnormality,and could be a potential biomarker for detecting early neurodegeneration in MS.
基金supported by the National Natural Science Foundation of China (61001209)Chinese State Oceanic Administration’s Special Funds for Scientific Research on Public Cause (200905029)+1 种基金the Fundamental Research Funds for the Central Universities (JY10000902010)the Aeronautical Science Fund(20100181010)
文摘In this paper, new Cramér-Rao lower bounds （CRB） of the estimates of frequencies, two-dimensional arrival angles and polarization parameters of multiple incident signals are derived for a polarization sensitive array. The incident sources have distinct carrier-frequencies, in contrast to the modeling of all sources to be at the same known carrier-frequency, which has been investigated in the existing research literature on the Cramér-Rao bounds （CRB） for polarization sensitive direction finding. The derived CRBs are compact closed-form expressions and applicable to an arbitrary array geometry. Numerical examples and analysis of some special cases provide insights into the fact that the estimation accuracy of all parameters is enhanced with the increasing signal-to-noise ratio （SNR） and number of snapshots. In addition, they are hardly influenced by the sampling frequency and independent of the initial phase of incident sources. These insights offer guidelines to the system engineer on how to improve parameters＇ estimation accuracy.
基金supported by the National Natural Science Foundation of China(11904108)the“Pearl River Talent Recruitment Program”(2019ZT08X639)Guangdong Basic and Applied Basic Research Foundation(2024A1515030107).
基金For the development of the generic PIC platform outlined in the article funding has been received from the European Commission through the projects EuroPIC(www.europic.jeppix.eu)PARADIGM(www.paradigm.jeppix.eu),and InPulse(www.inpulse.jeppix.eu).The 4-array EML chips(refer to Fig.7)was developed in the framework of the PIANO+-ALOHA project(grant#01BP1125).The other topics have been conducted on HHI internal funding.
文摘InP technology is the principal enabler for implementing fully monolithic photonic integrated circuits(PIC),uniquely including transmitter elements.In this article we present an overview of recent achievements on ultra-high speed electro-absorption modulated lasers(EML)which represent a simple transmitter PIC comprising a singlemode laser diode and an electro-absorption modulator.Using a so-called identicallayer approach single-wavelength modulation rates up to 100 Gb/s have been accomplished.By additionally integrating an optical amplifier section modulated optical output power of>10 dBm has been achieved.Multi-level amplitude modulation was successfully demonstrated.Extended EML chips designed for wavelength-division and space-division multiplexing,respectively,will be presented.For dual-polarization transmission a novel EML related transmitter as well as a corresponding receiver PIC have been introduced.The latter devices were made on a generic PIC platform that is available for open-access foundry service.
基金Supported by the National Natural Scie-nce Foundation of China
文摘The polarization sensitive CARS (coherent anti stokes Raman spectroscopy) method is used for the direct spectroscopic investigating of the vibration of double bonds in nucleiosides. The nonresonant background in CARS has been effectively suppressed and the vibration mode of these double bonds can be clearly resolved. The spectral features are discussed in terms of the characteristic group frequency and analogies with spectra of molecules with related structures. These spectral feature may be of use for studying biomolecules of unknown composition.
