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Infrared/Optical Photopolarimeter with Linear Arrays
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作者 Shuji Sato (Nagoya Univ) 《天文研究与技术》 CSCD 1999年第S1期44-50,共7页
We present prism spectro/photo/polarimeters employing linear detector arrays, and their scientific results for this decade. We put emphasis on the educational merits for begginers aiming at astronomical instrumentatio... We present prism spectro/photo/polarimeters employing linear detector arrays, and their scientific results for this decade. We put emphasis on the educational merits for begginers aiming at astronomical instrumentation as well as professional astronomical works. 展开更多
关键词 infrared/optical Photopolarimeter with Linear Arrays
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Study on correlation of thermal model to in-orbit data for infrared optical payloads on FY-3E/HIRAS-Ⅱ
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作者 LI Yu-Han YANG Bao-Yu +4 位作者 ZHANG Qiang GUO Zhi-Peng WU Yi-Nong TANG Xiao LI Shang-Ju 《红外与毫米波学报》 北大核心 2025年第3期394-405,共12页
The Infrared Hyperspectral Atmospheric SounderⅡ(HIRAS-Ⅱ)is the key equipment on FengYun-3E(FY-3E)satellite,which can realize vertical atmospheric detection,featuring hyper spectral,high sensitivity and high precisio... The Infrared Hyperspectral Atmospheric SounderⅡ(HIRAS-Ⅱ)is the key equipment on FengYun-3E(FY-3E)satellite,which can realize vertical atmospheric detection,featuring hyper spectral,high sensitivity and high precision.To ensure its accuracy of detection,it is necessary to correlate their thermal models to in-orbit da⁃ta.In this work,an investigation of intelligent correlation method named Intelligent Correlation Platform for Ther⁃mal Model(ICP-TM)was established,the advanced Kriging surrogate model and efficient adaptive region opti⁃mization algorithm were introduced.After the correlation with this method for FY-3E/HIRAS-Ⅱ,the results indi⁃cate that compared with the data in orbit,the error of the thermal model has decreased from 5 K to within±1 K in cold case(10℃).Then,the correlated model is validated in hot case(20℃),and the correlated model exhibits good universality.This correlation precision is also much superiors to the general ones like 3 K in other similar lit⁃erature.Furthermore,the process is finished in 8 days using ICP-TM,the efficiency is much better than 3 months based on manual.The results show that the proposed approach significantly enhances the accuracy and efficiency of thermal model,this contributes to the precise thermal control of subsequent infrared optical payloads. 展开更多
关键词 thermal model intelligent correlation method surrogate model infrared optical payload FY-3E
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Design and implementation of an integrated and rapidly assembled infrared three-band optical system
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作者 Shuanglong Tan Yulin Wang +3 位作者 Guangwei Shi Shuaiwei Mu Xin Zhang Lin Ma 《Astronomical Techniques and Instruments》 2025年第2期88-99,共12页
Continuing advancement in astronomy,space exploration,and scientific detection,has increased demand for infrared multi-band detection systems.Traditional three-band optical systems,designed to simultaneously image at ... Continuing advancement in astronomy,space exploration,and scientific detection,has increased demand for infrared multi-band detection systems.Traditional three-band optical systems,designed to simultaneously image at infrared short-wave,mid-wave,and long-wave bands typically rely on dispersive elements,leading to bulky sizes,complex system architectures,low efficiency,and challenges in rapid assembly.To overcome these obstacles,in combination with the latest third-generation infrared detectors,we propose a design for a compact and lightweight three-band optical system,with infrared capabilities in all three required bands.The core of this approach is an integrated design philosophy that emphasizes the high steepness of mirror surfaces.This design achieves uniform correction and optimization of chromatic aberration and off-axis aberration across the spectral range.We introduce a novel integration of optical and mechanical elements to replace traditional assembly,reducing manufacturing and assembly errors,and degrees of freedom,associated with high-power optical elements.Confirming the effectiveness through a combination of simulations and experimental comparisons,the measured mid-wave full-field transfer function exceeds 0.405 at 17 lp/mm,satisfying the imaging requirements of the system.The optical system is lightweight and compact,with a total mass under 408 g and a compact volume of justΦ112 mm×117 mm.This serves as a valuable reference for the engineering application of high-performance,compact multi-band infrared composite detection systems for astronomy and space exploration. 展开更多
关键词 Three-band infrared INTEGRATED Rapid assembly Modulation Transfer Function(MTF)
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All-chalcogenide glass based high fill-factor long-wave infrared micro-metalens array with superior optical flexibility
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作者 Zhaofeng Gu Kongsi Zhou +6 位作者 Tong Sun Yixiao Gao Yimin Chen Zijun Liu Chenjie Gu Pengfei Lu Xiang Shen 《Chinese Physics B》 2025年第7期402-408,共7页
Long-wave infrared(LWIR)micro-metalens arrays have emerged as highly flexible and multifunctional optical elements,significantly enhancing the performance of infrared imaging systems.In this work,two types of chalcoge... Long-wave infrared(LWIR)micro-metalens arrays have emerged as highly flexible and multifunctional optical elements,significantly enhancing the performance of infrared imaging systems.In this work,two types of chalcogenide glass based LWIR micro-metalens arrays with 10×10 array-size and 100%fill factor were designed and investigated.Specifically,the first one possesses a uniform focal length of 110μm,and it can efficiently focus the incident light(9.78μm)into a spot with a full width at half maximum(FWHM)of approximately 11.5μm(~1.18λ).Additionally,the second one features flexible and configurable focal lengths of the respective micro-metalenses in the array,and focal lengths of102μm,149μm,and 182μm can be achieved on one substrate,while it still retains the same optical performance as the micro-metalens array with a single focal length.Overall,these all-chalcogenide glass based LWIR micro-metasurface arrays possess significant potential for integrating within advanced infrared imaging systems in the future. 展开更多
关键词 chalcogenide glass multi-focal micro-metalens array long-wave infrared high fill factor
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Mid-infrared Optical Frequency Comb-based Fourier Transform Spectrometer for Broadband Molecular Spectroscopy 被引量:1
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作者 Feihu Cheng Weixiong Zhao +5 位作者 Bo Fang Nana Yang Shuangshuang Li Weijun Zhang Lunhua Deng Weidong Chen 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2024年第4期471-480,I0093,共11页
Optical frequency combbased Fourier transform spectroscopy has the features of broad spectral bandwidth,high sensitivity,andmultiplexed trace gas detection,which has valuable application potential in the fields of pre... Optical frequency combbased Fourier transform spectroscopy has the features of broad spectral bandwidth,high sensitivity,andmultiplexed trace gas detection,which has valuable application potential in the fields of precision spectroscopy and trace gas detection.Here,we report the development of a mid-infrared Fourier transform spectrometer based on an optical frequency comb combined with a Herriott-type multipass cell.Using this instrument,the broadband absorption spectra of several important molecules,including methane,acetylene,water molecules and nitrous oxide,are measured by near real-time data acquisition in the 2800-3500 cm^(-1)spectral region.The achieved minimum detectable absorption of the instrument is 4.4×10^(-8)cm^(-1)·Hz^(-1/2)per spectral element.Broadband spectra of H_(2)0 are fited using the Voigt profile multispectral fitting technique and the consistency of the concentration inversion is 1%.Our system also enables precise spectroscopic measurements,and it allows the determination of the spectral line positions and upper state constants of N_(2)O in the(0002)-(1000)band,with results in good agreement with those reported by Toth[Appl.Opt.30,5289(1991)]. 展开更多
关键词 Mid-infrared optical frequency comb Multi-pass cell Fourier transform infrared spectrometer
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Tetherless Optical Neuromodulation:Wavelength from Orange-red to Mid-infrared 被引量:1
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作者 Chao Sun Qi Fan +3 位作者 Rougang Xie Ceng Luo Bingliang Hu Quan Wang 《Neuroscience Bulletin》 SCIE CAS CSCD 2024年第8期1173-1188,共16页
Optogenetics,a technique that employs light for neuromodulation,has revolutionized the study of neural mechanisms and the treatment of neurological disorders due to its high spatiotemporal resolution and cell-type spe... Optogenetics,a technique that employs light for neuromodulation,has revolutionized the study of neural mechanisms and the treatment of neurological disorders due to its high spatiotemporal resolution and cell-type specificity.However,visible light,particularly blue and green light,commonly used in conventional optogenetics,has limited penetration in biological tissue.This limitation necessitates the implantation of optical fibers for light delivery,especially in deep brain regions,leading to tissue damage and experimental constraints.To overcome these challenges,the use of orange-red and infrared light with greater tissue penetration has emerged as a promising approach for tetherless optical neuromodulation.In this review,we provide an overview of the development and applications of tetherless optical neuromodulation methods with long wavelengths.We first discuss the exploration of orange-red wavelength-responsive rhodopsins and their performance in tetherless optical neuromodulation.Then,we summarize two novel tetherless neuromodulation methods using near-infrared light:upconversion nanoparticle-mediated optogenetics and photothermal neuromodulation.In addition,we discuss recent advances in mid-infrared optical neuromodulation. 展开更多
关键词 optical neuromodulation Tetherless Orange-red wavelength responding rhodopsins Upconversion nanoparticle-mediated optogenetics Photothermal neuromodulation
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ZnGa_(2)S_(4):an infrared nonlinear optical material with large second-harmonic generation response and wide band gap
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作者 Chen-Yang Zhang Xiao-Nan Niu +5 位作者 Yan-Feng Wei Shu-Xing Zhou Da-Qing Yang Ying Wang Jian Wang Bing-Bing Zhang 《Rare Metals》 SCIE EI CAS CSCD 2024年第1期395-401,共7页
High-performance nonlinear optical(NLO)crystals are crucial devices to convert wavelength of solid-state lasers.Chalcogenides play an indispensable role in the research of infrared NLO materials.In this work,ternary c... High-performance nonlinear optical(NLO)crystals are crucial devices to convert wavelength of solid-state lasers.Chalcogenides play an indispensable role in the research of infrared NLO materials.In this work,ternary chalcogenide ZnGa_(2)S_(4) with defect diamond-like structure was screened out and synthesized by chemical vapor transport method. 展开更多
关键词 optical NONLINEAR HARMONIC
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Broadband third-order optical nonlinearities of layered franckeite towards mid-infrared regime
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作者 Zhi-Qiang Xu Tian-Tian Zhou +7 位作者 Jie Li Dong-Yang Liu Yuan He Ning Li Xiao Liu Li-Li Miao Chu-Jun Zhao Shuang-Chun Wen 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第10期275-281,共7页
The study of nonlinear optical responses in the mid-infrared(mid-IR)regime is essential for advancing ultrafast mid-IR laser applications.However,nonlinear optical effects under mid-IR excitation are rarely reported d... The study of nonlinear optical responses in the mid-infrared(mid-IR)regime is essential for advancing ultrafast mid-IR laser applications.However,nonlinear optical effects under mid-IR excitation are rarely reported due to the lack of suitable nonlinear optical materials.The natural van derWaals heterostructure franckeite,known for its narrow bandgap and stability in air,shows great potential for developing mid-IR nonlinear optical devices.We have experimentally demonstrated that layered franckeite exhibits a broadband wavelength-dependent nonlinear optical response in the mid-IR spectral region.Franckeite nanosheets were prepared using a liquid-phase exfoliation method,and their nonlinear optical response was characterized in the spectral range of 3000 nm to 5000 nm.The franckeite nanosheets exhibit broadband wavelengthdependent third-order nonlinearities,with nonlinear absorption and refraction coefficients estimated to be about 10^(-7)cm/W and 10^(-11)cm^(2)/W,respectively.Additionally,a passively Q-switched fluoride fiber laser operating around a wavelength of 2800 nm was achieved,delivering nanosecond pulses with a signal-to-noise ratio of 43.6 dB,based on the nonlinear response of franckeite.These findings indicate that layered franckeite possesses broadband nonlinear optical characteristics in the mid-IR region,potentially enabling new possibilities for mid-IR photonic devices. 展开更多
关键词 third-order optical nonlinearities franckeite MID-infrared Q-SWITCHING
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Optical design of a novel near-infrared phase contrast imaging(NI-PCI)diagnostic on the HL-2A tokamak
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作者 徐皓 龚少博 +11 位作者 余羿 许敏 兰涛 王志斌 石中兵 聂林 赵光义 刘灏 周艺轩 袁子豪 肖晨雨 陈坚 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第3期31-37,共7页
The optical design of near-infrared phase contrast imaging(NI-PCI)diagnosis on HL-2A is introduced in this paper.This scheme benefits from the great progress of near-infrared laser technology and is a broadening of tr... The optical design of near-infrared phase contrast imaging(NI-PCI)diagnosis on HL-2A is introduced in this paper.This scheme benefits from the great progress of near-infrared laser technology and is a broadening of traditional phase contrast technology.This diagnostic can work as a keen tool to measure plasma wavenumber spectra by inferring string-integrated plasma density fluctuations.Design of both the front optical path which is the path before the laser transmitting into the tokamak plasma and the rear optics which is the path after the laser passing through the plasma is detailed.The 1550 nm laser is chosen as the probe beam and highprecision optical components are designed to fit the laser beam,in which a phase plate with a 194-nm-deep silver groove is the key.Compared with the conventional 10.6μm laser-based PCI system on HL-2A,NI-PCI significantly overcomes the unwanted phase scintillation effect and promotes the measurement capability of high-wavenumber turbulence with an increased maximal measurable wavenumber from 15 cm^(-1)to 32.6 cm^(-1). 展开更多
关键词 phase contrast imaging near infrared laser plasma laser diagnostic
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Generation of tunable high-order Laguerre– Gaussian petal-like modes from a mid-infrared optical vortex parametric oscillator
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作者 Yuxia Zhou Xining Yang +4 位作者 Jianqiang Ye Yuanyuan Ma Ying Wan Jianxiang Wen Taximaiti Yusufu 《Advanced Photonics Nexus》 2024年第3期113-119,共7页
High-order Laguerre–Gaussian(LG)petal-like beams have become a topic of significant interest due to their potential application in next-generation optical trapping,quantum optics,and materials processing technologies... High-order Laguerre–Gaussian(LG)petal-like beams have become a topic of significant interest due to their potential application in next-generation optical trapping,quantum optics,and materials processing technologies.In this work,we demonstrate the generation of high-order LG beams with petal-like spatial profiles and tunable orbital angular momentum(OAM)in the mid-infrared wavelength region.These beams are generated using idler-resonant optical parametric oscillation(OPO)in a KTiOAsO_(4)(KTA)crystal.By adjusting the length of the resonant cavity,the OAM of the mid-infrared idler field can be tuned and we demonstrate tuning in the range of 0 to10.When using a maximum pump energy of 20.2 mJ,the maximum output energy of high-order modes LG_(0.45),LG_(0.48),and LG_(0.410) were 0.8,0.53,and 0.46 mJ,respectively.The means by which high-order LG modes with petal-like spatial profiles and tunable OAM were generated from the OPO is theoretically modeled by examining the spatial overlap efficiency of the beam waists of the pump and resonant idler fields within the center of the KTA crystal.The methodology presented in this work offers a simple and flexible method to wavelength-convert laser emission and generate high-order LG modes. 展开更多
关键词 high-order Laguerre-Gaussian petal-like modes optical parametric oscillator nonlinear optics KTiOAsO_(4) optical vortices.
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Macular microvascular and structural changes on optical coherence tomography angiography in atypical optic neuritis 被引量:1
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作者 Chinmay Mahatme Madhurima Kaushik +2 位作者 Veerappan Rathinasabapathy Saravanan Karthik Kumar Virna M Shah 《World Journal of Methodology》 2025年第1期88-94,共7页
BACKGROUND Atypical optic neuritis,consisting of neuromyelitis optica spectrum disorders(NMOSD)or myelin oligodendrocyte glycoprotein antibody disease(MOGAD),has a very similar presentation but different prognostic im... BACKGROUND Atypical optic neuritis,consisting of neuromyelitis optica spectrum disorders(NMOSD)or myelin oligodendrocyte glycoprotein antibody disease(MOGAD),has a very similar presentation but different prognostic implications and longterm management strategies.Vascular and metabolic factors are being thought to play a role in such autoimmune neuro-inflammatory disorders,apart from the obvious immune mediated damage.With the advent of optical coherence tomography angiography(OCTA),it is easy to pick up on these subclinical macular microvascular and structural changes.AIM To study the macular microvascular and structural changes on OCTA in atypical optic neuritis.METHODS This observational cross-sectional study involved 8 NMOSD and 17 MOGAD patients,diagnosed serologically,as well as 10 healthy controls.Macular vascular density(MVD)and ganglion cell+inner plexiform layer thickness(GCIPL)were studied using OCTA.RESULTS There was a significant reduction in MVD in NMOSD and MOGAD affected as well as unaffected eyes when compared with healthy controls.NMOSD and MOGAD affected eyes had significant GCIPL thinning compared with healthy controls.NMOSD unaffected eyes did not show significant GCIPL thinning compared to healthy controls in contrast to MOGAD unaffected eyes.On comparing NMOSD with MOGAD,there was no significant difference in terms of MVD or GCIPL in the affected or unaffected eyes.CONCLUSION Although significant microvascular and structural changes are present on OCTA between atypical optic neuritis and normal patients,they could not help in differentiating between NMOSD and MOGAD cases. 展开更多
关键词 optical coherence tomography angiography Atypical optic neuritis Macular microvascular changes Neuromyelitis optica spectrum disorders Myelin oligodendrocyte glycoprotein antibody disorder
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Performance and electromagnetic mechanism of radar-and infraredcompatible stealth materials based on photonic crystals 被引量:2
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作者 Yanming Liu Xuan Yang +3 位作者 Lixin Xuan Weiwei Men Xiao Wu Yuping Duan 《International Journal of Minerals,Metallurgy and Materials》 2025年第3期710-717,共8页
Traditional stealth materials do not fulfill the requirements of high absorption for radar waves and low emissivity for infrared waves.Furthermore,they can be detected by various technologies,considerably threatening ... Traditional stealth materials do not fulfill the requirements of high absorption for radar waves and low emissivity for infrared waves.Furthermore,they can be detected by various technologies,considerably threatening weapon safety.Therefore,a stealth material compatible with radar and infrared was designed based on the photonic bandgap characteristics of photonic crystals.The radar stealth lay-er(bottom layer)is a composite of carbonyl iron/silicon dioxide/epoxy resin,and the infrared stealth layer(top layer)is a 1D photonic crystal with alternately and periodically stacked germanium and silicon nitride.Through composition optimization and structural adjust-ment,the effective absorption bandwidth of the compatible stealth material with a reflection loss of less than-10 dB has reached 4.95 GHz.The average infrared emissivity of the proposed design is 0.1063,indicating good stealth performance.The theoretical analysis proves that photonic crystals with this structural design can produce infrared waves within the photonic bandgap,achieving high radar wave transmittance and low infrared emissivity.Infrared stealth is achieved without affecting the absorption performance of the radar stealth layer,and the conflict between radar and infrared stealth performance is resolved.This work aims to promote the application of photonic crystals in compatible stealth materials and the development of stealth technology and to provide a design and theoretical found-ation for related experiments and research. 展开更多
关键词 microwave absorption infrared stealth photonic crystal compatible stealth
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High-efficiency RGB achromatic liquid crystal diffractive optical elements 被引量:1
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作者 Yuqiang Ding Xiaojin Huang +2 位作者 Yongziyan Ma Yan Li Shin-Tson Wu 《Opto-Electronic Advances》 2025年第3期4-15,共12页
Liquid crystal Pacharatnam-Berry phase optical elements(PBOEs)have found promising applications in augmented reality and virtual reality because of their slim formfactor,lightweight,and high optical efficiency.However... Liquid crystal Pacharatnam-Berry phase optical elements(PBOEs)have found promising applications in augmented reality and virtual reality because of their slim formfactor,lightweight,and high optical efficiency.However,chromatic aberration remains a serious longstanding problem for diffractive optics,hindering their broader adoption.To overcome the chromatic aberrations for red,green and blue(RGB)light sources,in this paper,we propose a counterintuitive multi-twist structure to achieve narrowband PBOEs without crosstalk,which plays a vital role to eliminate the chromatic aberration.The performance of our designed and fabricated narrowband Pacharatnam-Berry lenses(PBLs)aligns well with our simulation results.Furthermore,in a feasibility demonstration experiment using a laser projector,our proposed PBL system indeed exhibits a diminished chromatic aberration as compared to a broadband PBL.Additionally,polarization raytracing is implemented to demonstrate the versatility of the multi-twist structure for designing any RGB wavelengths with high contrast ratios.This analysis explores the feasibility of using RGB laser lines and quantum dot light-emitting diodes.Overall,our approach enables high optical efficiency,low fabrication complexity,and high degree of design freedom to accommodate any liquid crystal material and RGB light sources,holding immense potential for widespread applications of achromatic PBOEs. 展开更多
关键词 achromatic diffractive optical elements Pacharatnam-Berry phase optical elements liquid crystal planar optics near-eye displays
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Single-beam optical trap-based surfaceenhanced raman scattering optofluidic molecular fingerprint spectroscopy detection system 被引量:1
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作者 Ning Sun Yuan Gan +4 位作者 Yujie Wu Xing Wang Shen Shen Yong Zhu Jie Zhang 《Opto-Electronic Advances》 2025年第2期16-27,共12页
In this study,we developed a single-beam optical trap-based surface-enhanced Raman scattering(SERS)optofluidic molecular fingerprint spectroscopy detection system.This system utilizes a single-beam optical trap to con... In this study,we developed a single-beam optical trap-based surface-enhanced Raman scattering(SERS)optofluidic molecular fingerprint spectroscopy detection system.This system utilizes a single-beam optical trap to concentrate free silver nanoparticles(AgNPs)within an optofluidic chip,significantly enhancing SERS performance.We investigated the optical field distribution characteristics within the tapered fiber using COMSOL simulation software and established a MATLAB simulation model to validate the single-beam optical trap's effectiveness in capturing AgNPs,demonstrating the theoretical feasibility of our approach.To verify the particle capture efficacy of the system,we experimentally controlled the optical trap's on-off state to manage the capture and release of particles precisely.The experimental results indicated that the Raman signal intensity in the capture state was significantly higher than in the non-capture state,confirming that the single-beam optical trap effectively enhances the SERS detection capability of the optofluidic detection system.Furthermore,we employed Raman mapping techniques to investigate the impact of the capture area on the SERS effect,revealing that the spectral intensity of molecular fingerprints in the laser-trapping region is significantly improved.We successfully detected the Raman spectrum of crystal violet at a concentration of 10^(−9)mol/L and pesticide thiram at a concentration of 10^(−5)mol/L,further demonstrating the ability of the single-beam optical trap in enhancing the molecular fingerprint spectrum identification capability of the SERS optofluidic chips.The optical trapping SERS optofluidic detection system developed in this study,as a key component of an integrated optoelectronic sensing system,holds the potential for integration with portable high-power lasers and high-performance Raman spectrometers.This integration is expected to advance highly integrated technologies and significantly enhance the overall performance and portability of optoelectronic sensing systems. 展开更多
关键词 surface-enhanced Raman scattering optofluidic single-beam optical trap tapered optical fibers
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Integrated Optical True Time Delay Phased Array Antenna Systems 被引量:1
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作者 Qi Zihang Yang Linhui +1 位作者 Zhao Wenyu Li Xiuping 《China Communications》 2025年第5期152-172,共21页
The integrated optical true time delay phased array antenna system has the advantages of high bandwidth,small size,low loss and strong antiinterference capability,etc.The high integration of the optically controlled p... The integrated optical true time delay phased array antenna system has the advantages of high bandwidth,small size,low loss and strong antiinterference capability,etc.The high integration of the optically controlled phased array antenna system is a necessary trend for the future development of the phased array,and it is also a major focus and difficulty in the current research of integrated microwave photonics.This paper firstly introduces the basic principle and development history of optical true time delay phased array antenna system based on microwave photonics,and briefly introduces the main implementation methods and integration platform of optical true time delay.Then,the application and development prospect of optical true time delay technology in beam control of phased array antenna system are mainly presented.Finally,according to the current research progress,the possible research directions of integrated optically controlled phased array antenna systems in the future are proposed. 展开更多
关键词 microwave photonics optical switch optical true time delay phased array antenna siliconbased integration
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Development of Fully Self-Controllable High-Finesse Optical Reference Cavities 被引量:1
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作者 Dongdong Jiao Mengfan Wu +9 位作者 Jing Gao Han Zhang Junlong Liu Guanjun Xu Qi Zang Jie Cui Ruifang Dong Tao Liu Bo Qu Shougang Zhang 《Chinese Physics Letters》 2025年第1期53-57,共5页
High-finesse optical reference cavities are essential tools for fundamental research.In response to China’s historical reliance on importing high-finesse optical reference cavities,we successfully developed a cavity ... High-finesse optical reference cavities are essential tools for fundamental research.In response to China’s historical reliance on importing high-finesse optical reference cavities,we successfully developed a cavity using ultralow expansion glass(ULE)materials and processed it entirely in China.Using the method of measuring the cavity linewidth,a finesse of approximately 480000 was obtained in our experiments.We adopted a relatively simple and effective approach to test the optical reference cavity,which involved measuring the resonant points using an ultrastable laser.Remarkably,an expansion coefficient of the Chinese ULE optical reference cavity reached up to the order of 10^(-9)/K within the temperature range of 27℃to 40℃,with the zero expansion point occurring at approximately 34oC.These findings demonstrate China’s independent capability to develop high-finesse optical reference cavities,which is a significant advancement in precision optics. 展开更多
关键词 optical CAVITY EXPANSION
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Optical coherence tomography angiography in diabetic retinopathy:focusing on microvascular changes 被引量:4
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作者 Yang Xiongyi Yi Guoguo +5 位作者 Chen Yanxia Yang Siyu Ai Shibei Zheng Cong Cao Mingzhe Fu Min 《国际眼科杂志》 2025年第2期179-190,共12页
AIM:To investigate the value of optical coherence tomography angiography(OCTA)indicators in the diagnosis of diabetic retinopathy(DR),and to provide patients with diabetic nephropathy(DN)with more sensitive OCTA scree... AIM:To investigate the value of optical coherence tomography angiography(OCTA)indicators in the diagnosis of diabetic retinopathy(DR),and to provide patients with diabetic nephropathy(DN)with more sensitive OCTA screening indicators to detect concurrent DR at an early stage.METHODS:A total of 200 patients who treated in the ophthalmology department of the Seventh Affiliated Hospital,Sun Yat-sen University from 2022 to 2023 were included,including 95 first-diagnosed DR patients and 105 patients without DR,and all patients underwent OCTA examination and a collection of demographics and renal function parameters.After a quality check,automated measurements of the foveal avascular zone area,vessel density(VD),and perfusion density(PD)of both 3 mm×3 mm and 6 mm×6 mm windows were obtained.RESULTS:Using random forest and multivariate Logistic regression methods,we developed a diagnostic model for DR based on 12 variables(age,FBG,SBP,DBP,HbA1c,ALT,ALP,urea/Scr,DM duration,HUA,DN,and CMT).Adding specific OCTA parameters enhanced the efficacy of the existing diagnostic model for DR(outer vessel density in 6 mm×6 mm window,AUC=0.837 vs 0.819,P=0.03).In the study of DN patients,the parameters in the 6 mm×6 mm window improved the diagnostic efficacy of DR(inner VD;outer VD;full VD;outer PD;full PD).CONCLUSION:The outer VD in the 6 mm×6 mm window can enhance the efficacy of the traditional DR diagnostic model.Meanwhile,compared with the 3 mm×3 mm window,the microvascular parameters in the 6 mm×6 mm window focusing on DN patients can be more sensitive to diagnosing the occurrence of DR. 展开更多
关键词 optical coherence tomography angiography(OCTA) diabetic retinopathy diabetic nephropathy prediction model
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Hierarchically Porous Polypyrrole Foams Contained Ordered Polypyrrole Nanowire Arrays for Multifunctional Electromagnetic Interference Shielding and Dynamic Infrared Stealth 被引量:1
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作者 Yu-long Liu Ting-yu Zhu +5 位作者 Qin Wang Zi-jie Huang De-xiang Sun Jing-hui Yang Xiao-dong Qi Yong Wang 《Nano-Micro Letters》 2025年第4期399-418,共20页
As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal... As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal conversion ability have received extensive attention.Meeting the aforesaid requirements simultaneously remains a huge challenge.In this research,the melamine foam(MF)/polypyrrole(PPy)nanowire arrays(MF@PPy)were fabricated via one-step electrochemical polymerization.The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays.Due to the upwardly grown PPy nanowire arrays,the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00°and outstanding stability under various harsh environments.Meanwhile,the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays.Furthermore,taking advantage of the high conductivity(128.2 S m^(-1)),the MF@PPy foam exhibited rapid Joule heating under 3 V,resulting in dynamic infrared stealth and thermal camouflage effects.More importantly,the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm^(2)g^(-1).Strong EMI shielding was put down to the hierarchically porous PPy structure,which offered outstanding impedance matching,conduction loss,and multiple attenuations.This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays,showing great applications in both military and civilian fields. 展开更多
关键词 Polypyrrole nanowire arrays Hierarchical foam HYDROPHOBICITY infrared stealth Electromagnetic interference shielding
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IoT Empowered Early Warning of Transmission Line Galloping Based on Integrated Optical Fiber Sensing and Weather Forecast Time Series Data 被引量:1
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作者 Zhe Li Yun Liang +1 位作者 Jinyu Wang Yang Gao 《Computers, Materials & Continua》 SCIE EI 2025年第1期1171-1192,共22页
Iced transmission line galloping poses a significant threat to the safety and reliability of power systems,leading directly to line tripping,disconnections,and power outages.Existing early warning methods of iced tran... Iced transmission line galloping poses a significant threat to the safety and reliability of power systems,leading directly to line tripping,disconnections,and power outages.Existing early warning methods of iced transmission line galloping suffer from issues such as reliance on a single data source,neglect of irregular time series,and lack of attention-based closed-loop feedback,resulting in high rates of missed and false alarms.To address these challenges,we propose an Internet of Things(IoT)empowered early warning method of transmission line galloping that integrates time series data from optical fiber sensing and weather forecast.Initially,the method applies a primary adaptive weighted fusion to the IoT empowered optical fiber real-time sensing data and weather forecast data,followed by a secondary fusion based on a Back Propagation(BP)neural network,and uses the K-medoids algorithm for clustering the fused data.Furthermore,an adaptive irregular time series perception adjustment module is introduced into the traditional Gated Recurrent Unit(GRU)network,and closed-loop feedback based on attentionmechanism is employed to update network parameters through gradient feedback of the loss function,enabling closed-loop training and time series data prediction of the GRU network model.Subsequently,considering various types of prediction data and the duration of icing,an iced transmission line galloping risk coefficient is established,and warnings are categorized based on this coefficient.Finally,using an IoT-driven realistic dataset of iced transmission line galloping,the effectiveness of the proposed method is validated through multi-dimensional simulation scenarios. 展开更多
关键词 optical fiber sensing multi-source data fusion early warning of galloping time series data IOT adaptive weighted learning irregular time series perception closed-loop attention mechanism
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YOLO-Fastest-IR:Ultra-lightweight thermal infrared face detection method for infrared thermal camera
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作者 LI Xi-Cai ZHU Jia-He +1 位作者 DONG Peng-Xiang WANG Yuan-Qing 《红外与毫米波学报》 北大核心 2025年第5期790-800,共11页
This paper presents a high-speed and robust dual-band infrared thermal camera based on an ARM CPU.The system consists of a low-resolution long-wavelength infrared detector,a digital temperature and humid⁃ity sensor,an... This paper presents a high-speed and robust dual-band infrared thermal camera based on an ARM CPU.The system consists of a low-resolution long-wavelength infrared detector,a digital temperature and humid⁃ity sensor,and a CMOS sensor.In view of the significant contrast between face and background in thermal infra⁃red images,this paper explores a suitable accuracy-latency tradeoff for thermal face detection and proposes a tiny,lightweight detector named YOLO-Fastest-IR.Four YOLO-Fastest-IR models(IR0 to IR3)with different scales are designed based on YOLO-Fastest.To train and evaluate these lightweight models,a multi-user low-resolution thermal face database(RGBT-MLTF)was collected,and the four networks were trained.Experiments demon⁃strate that the lightweight convolutional neural network performs well in thermal infrared face detection tasks.The proposed algorithm outperforms existing face detection methods in both positioning accuracy and speed,making it more suitable for deployment on mobile platforms or embedded devices.After obtaining the region of interest(ROI)in the infrared(IR)image,the RGB camera is guided by the thermal infrared face detection results to achieve fine positioning of the RGB face.Experimental results show that YOLO-Fastest-IR achieves a frame rate of 92.9 FPS on a Raspberry Pi 4B and successfully detects 97.4%of faces in the RGBT-MLTF test set.Ultimate⁃ly,an infrared temperature measurement system with low cost,strong robustness,and high real-time perfor⁃mance was integrated,achieving a temperature measurement accuracy of 0.3℃. 展开更多
关键词 artificial intelligence infrared face detection ultra-lightweight network infrared thermal camera YOLO-Fastest-IR
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