2024

• Record 325 of
  
  Title:A Snapshot Multi-Spectral Demosaicing Method for Multi-Spectral Filter Array Images Based on Channel Attention Network
  
  Author Full Names:Zhang, Xuejun; Dai, Yidan; Zhang, Geng; Zhang, Xuemin; Hu, Bingliang

  Source Title:SENSORS

  Language:English

  Document Type:Article

  Keywords Plus:CONVOLUTIONAL NETWORK; SYSTEM; QUALITY

  Abstract:Multi-spectral imaging technologies have made great progress in the past few decades. The development of snapshot cameras equipped with a specific multi-spectral filter array (MSFA) allow dynamic scenes to be captured on a miniaturized platform across multiple spectral bands, opening up extensive applications in quantitative and visualized analysis. However, a snapshot camera based on MSFA captures a single band per pixel; thus, the other spectral band components of pixels are all missed. The raw images, which are captured by snapshot multi-spectral imaging systems, require a reconstruction procedure called demosaicing to estimate a fully defined multi-spectral image (MSI). With increasing spectral bands, the challenge of demosaicing becomes more difficult. Furthermore, the existing demosaicing methods will produce adverse artifacts and aliasing because of the adverse effects of spatial interpolation and the inadequacy of the number of layers in the network structure. In this paper, a novel multi-spectral demosaicing method based on a deep convolution neural network (CNN) is proposed for the reconstruction of full-resolution multi-spectral images from raw MSFA-based spectral mosaic images. The CNN is integrated with the channel attention mechanism to protect important channel features. We verify the merits of the proposed method using 5 x 5 raw mosaic images on synthetic as well as real-world data. The experimental results show that the proposed method outperforms the existing demosaicing methods in terms of spatial details and spectral fidelity.

  Addresses:[Zhang, Xuejun; Dai, Yidan; Zhang, Geng; Hu, Bingliang] Chinese Acad Sci, Xian Inst Opt & Precis Mech, Xian 710119, Peoples R China; [Zhang, Xuejun; Dai, Yidan] Univ Chinese Acad Sci, Beijing 100049, Peoples R China; [Zhang, Xuemin] Wuhan Univ, Inst Aerosp Sci & Technol, Sch Remote Sensing & Informat Engn, Wuhan, Hubei, Peoples R China

  Affiliations:Chinese Academy of Sciences; Xi'an Institute of Optics & Precision Mechanics, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS; Wuhan University

  Publication Year:2024

  Volume:24

  Issue:3

  Article Number:943

  DOI Link:http://dx.doi.org/10.3390/s24030943

  数据库ID（收录号）:WOS:001160273300001
• Record 326 of
  
  Title:High-performance architecture for real-time high-definition short-wave infrared streaming video processing and its field programmable gate array prototype
  
  Author Full Names:Zhou, Feng; Chen, Zhiqiang; Xie, Qingsheng; Kong, Fanzi; Chen, Yaohong; Wang, Huawei

  Source Title:OPTICAL ENGINEERING

  Language:English

  Document Type:Article

  Keywords Plus:DETAIL ENHANCEMENT; IMAGES

  Abstract:. Image detail enhancement is critical to the performance of short-wave infrared (SWIR) imaging systems. Recently, the requirement for real-time processing of high-definition (HD) SWIR video has shown rapid growth. Nevertheless, the research on field programmable gate array (FPGA) implementation of HD SWIR streaming video processing architecture is relatively few. This work proposes a real-time FPGA architecture of SWIR video enhancement by combining the difference of Gaussian filter and plateau equalization. To accelerate the algorithm and reduce memory bandwidth, two efficient key architectures, namely edge information extraction and equalization and remapping architecture, are proposed to sharpen edges and improve dynamic range. The experimental results demonstrated that the proposed architecture achieved a real-time processing of 1280 x 1024@60Hz with 2.7K lookup tables, 2.5K Slice Reg, and about 350 kb of block RAM consumption, and their utilization reached 12.5%, 19.2%, and 12.5% for the XC7A200T FPGA board, respectively. Moreover, the proposed architecture is fully pipelined and synchronized to the pixel clock of output video, meaning that it can be seamlessly integrated into diverse real-time video processing systems.

  Addresses:[Zhou, Feng; Chen, Zhiqiang; Xie, Qingsheng; Kong, Fanzi; Chen, Yaohong; Wang, Huawei] Chinese Acad Sci, Xian Inst Opt & Precis Mech, Xian, Peoples R China; [Zhou, Feng; Chen, Zhiqiang; Kong, Fanzi] Univ Chinese Acad Sci, Beijing, Peoples R China; [Zhou, Feng; Chen, Zhiqiang; Xie, Qingsheng; Kong, Fanzi; Chen, Yaohong; Wang, Huawei] Xian Key Lab Spacecraft Opt Imaging & Measurement, Xian, Peoples R China

  Affiliations:Chinese Academy of Sciences; Xi'an Institute of Optics & Precision Mechanics, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS

  Publication Year:2024

  Volume:63

  Issue:2

  DOI Link:http://dx.doi.org/10.1117/1.OE.63.2.023103

  数据库ID（收录号）:WOS:001184522600003
• Record 327 of
  
  Title:Process optimization of infrared chalcogenide glass based on the scattering detection
  
  Author Full Names:Tang, Yuxin; Xu, Yantao; Cui, Xiaoxia; Zhang, Jinchang; Li, Man; Xiao, Xusheng; Yan, Mengmeng; Guo, Haitao

  Source Title:CERAMICS INTERNATIONAL

  Language:English

  Document Type:Article

  Keywords Plus:LOSSES

  Abstract:Chalcogenide glasses with less optical losses are highly demanded as optical materials for micro lense, waveguide and fiber devices. However, it is still challengeable to reduce the optical losses in infrared chalcogenide glasses with opaque visible light. Herein, an improved 3D distribution of scattering sources is established in this study to test and compare the concentration and distribution of defects in As38S62, Ge28Sb12Se60 and As40Se60 chalcogenide glasses. Furthermore, by comparing the scattering images of serial As40Se60 glass prepared under various melting, quenching and annealing temperatures, the preparation process was optimized to reduce its scattering loss. In addition, this study introduced a scheme that could be widely applied to optimize processing of other infrared glasses and devices glass to reduce their scattering losses.

  Addresses:[Tang, Yuxin; Xu, Yantao; Cui, Xiaoxia; Zhang, Jinchang; Xiao, Xusheng; Guo, Haitao] Chinese Acad Sci, Xian Inst Opt & Precis Mech, State Key Lab Transient Opt & Photon, Xian 710119, Shaanxi, Peoples R China; [Tang, Yuxin; Xu, Yantao; Cui, Xiaoxia; Zhang, Jinchang; Xiao, Xusheng; Guo, Haitao] Univ Chinese Acad Sci, Ctr Mat Sci & Optoelect Engn, Beijing 100049, Peoples R China; [Li, Man; Yan, Mengmeng; Guo, Haitao] Natl Key Lab Electromagnet Space Secur, Tianjin 300308, Peoples R China

  Affiliations:State Key Laboratory of Transient Optics & Photonics; Chinese Academy of Sciences; Xi'an Institute of Optics & Precision Mechanics, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS

  Publication Year:2024

  Volume:50

  Issue:5

  Start Page:7411

  End Page:7417

  DOI Link:http://dx.doi.org/10.1016/j.ceramint.2023.12.020

  数据库ID（收录号）:WOS:001170198600001
• Record 328 of
  
  Title:Reduced eye gaze fixation during emotion recognition among patients with temporal lobe epilepsy
  
  Author Full Names:Huang, Kailing; Tian, Ziwei; Zhang, Qiong; Yang, Haojun; Wen, Shirui; Feng, Jie; Tang, Weiting; Wang, Quan; Feng, Li

  Source Title:JOURNAL OF NEUROLOGY

  Language:English

  Document Type:Article

  Keywords Plus:SOCIAL COGNITION; ADULTS; MIND; IMPAIRMENT; STIMULI; FEAR

  Abstract:ObjectivesTo investigate the facial scan patterns during emotion recognition (ER) through the dynamic facial expression task and the awareness of social interference test (TASIT) using eye tracking (ET) technology, and to find some ET indicators that can accurately depict the ER process, which is a beneficial supplement to existing ER assessment tools.MethodNinety-six patients with TLE and 88 healthy controls (HCs) were recruited. All participants watched the dynamic facial expression task and TASIT including a synchronized eye movement recording and recognized the emotion (anger, disgust, happiness, or sadness). The accuracy of ER was recorded. The first fixation time, first fixation duration, dwell time, and fixation count were selected and analyzed.ResultsTLE patients exhibited ER impairment especially for disgust (Z = - 3.391; p = 0.001) and sadness (Z = - 3.145; p = 0.002). TLE patients fixated less on the face, as evidenced by the reduced fixation count (Z = - 2.549; p = 0.011) of the face and a significant decrease in the fixation count rate (Z = - 1.993; p = 0.046). During the dynamic facial expression task, TLE patients focused less on the eyes, as evidenced by the decreased first fixation duration (Z = - 4.322; p = 0.000), dwell time (Z = - 4.083; p = 0.000), and fixation count (Z = - 3.699; p = 0.000) of the eyes.ConclusionTLE patients had ER impairment, especially regarding negative emotions, which may be attributable to their reduced fixation on the eyes during ER, and the increased fixation on the mouth could be a compensatory effect to improve ER performance. Eye-tracking technology could provide the process indicators of ER, and is a valuable supplement to traditional ER assessment tasks.

  Addresses:[Huang, Kailing; Zhang, Qiong; Yang, Haojun; Wen, Shirui; Feng, Jie; Tang, Weiting; Feng, Li] Cent South Univ, Xiangya Hosp, Dept Neurol, Changsha 410008, Peoples R China; [Huang, Kailing; Zhang, Qiong; Yang, Haojun; Wen, Shirui; Feng, Jie; Tang, Weiting; Feng, Li] Cent South Univ, Xiangya Hosp, Natl Clin Res Ctr Geriatr Disorders, Changsha 410008, Hunan, Peoples R China; [Tian, Ziwei; Wang, Quan] Chinese Acad Sci, Key Lab Biomed Spect Xian, Xian Inst Opt & Precis Mech, Xian 710119, Peoples R China; [Tian, Ziwei; Wang, Quan] Chinese Acad Sci, Key Lab Spectral Imaging Technol, Xian Inst Opt & Precis Mech, Xian 710119, Peoples R China; [Tian, Ziwei] Univ Chinese Acad Sci, Beijing 101400, Peoples R China; [Feng, Li] Cent South Univ, Xiangya Hosp, Dept Neurol, Jiangxi Branch, Nanchang 330000, Jiangxi, Peoples R China

  Affiliations:Central South University; Central South University; Chinese Academy of Sciences; Xi'an Institute of Optics & Precision Mechanics, CAS; Chinese Academy of Sciences; Xi'an Institute of Optics & Precision Mechanics, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS

  Publication Year:2024

  Volume:271

  Issue:5

  Start Page:2560

  End Page:2572

  DOI Link:http://dx.doi.org/10.1007/s00415-024-12202-w

  数据库ID（收录号）:WOS:001153491300002
• Record 329 of
  
  Title:Characterization of primary silicate minerals in Earth-like bodies via Raman spectroscopy
  
  Author Full Names:Huang, Shuaidong; Xue, Bin; Zhao, Yiyi; Yang, Jianfeng

  Source Title:JOURNAL OF RAMAN SPECTROSCOPY

  Language:English

  Document Type:Article

  Keywords Plus:INFRARED-SPECTROSCOPY; VIBRATIONAL-SPECTRA; MICROPROBE SPECTRA; OLIVINE; FELDSPAR; PLAGIOCLASE; TEMPERATURE; FORSTERITE; MONTICELLITE; CRYSTALLINE

  Abstract:The examination and identification of silicate minerals are critical for advancing our understanding of the evolutionary journey of Earth-like bodies. To facilitate an efficient and productive process, it is imperative that these minerals be detected swiftly and accurately. This study is designed to explore the relationship between varying concentrations of cations and their corresponding Raman shifts. The focus is on primary silicate minerals in Earth-like bodies, specifically olivine, pyroxene, and feldspar, utilizing data from the RRUFF database. Employing a fitting formula, we identify distinct Raman peak ranges associated with different silicate minerals. Our research covers a wide array of mineral types, including five varieties of olivine (forsterite [Mg2SiO4], fayalite [Fe2+2SiO4], tephroite [Mn2+2SiO4], monticellite [CaMgSiO4], and kirschsteinite [CaFe2+SiO4]), four types of pyroxene (ferrosilite [Fe2+2Si2O6], enstatite [Mg2Si2O6], hedenbergite [CaFe2+Si2O6], and diopside [CaMgSi2O6]), and three varieties of feldspar (alkali feldspar [KAlSi3O8], albite [NaAlSi3O8], and anorthite [CaAl2Si2O8]). The accuracy of matching Raman characteristics is exceptionally high for all olivine and pyroxene types (100%) and an impressive 86% for feldspar. The findings from this study highlight the crucial role of Raman spectroscopy in the field of silicate mineralogy and suggest significant implications for enhancing future exploration missions to Earth-like bodies. In this paper, the Raman spectral characteristics of primary minerals in Earth-like bodies were specified by using RRUFF database to analysis. The success rate in matching Raman characteristics is notably high for all olivine and pyroxene types (100%) and a commendable 86% for feldspar. The identification uses fewer peaks, resulting in a higher accuracy. image

  Addresses:[Huang, Shuaidong; Xue, Bin; Zhao, Yiyi; Yang, Jianfeng] Xian Inst Opt & Precis Mech, Chinese Acad Sci, Xian, Peoples R China; [Huang, Shuaidong; Xue, Bin; Zhao, Yiyi; Yang, Jianfeng] Univ Chinese Acad Sci, Beijing, Peoples R China

  Affiliations:Chinese Academy of Sciences; Xi'an Institute of Optics & Precision Mechanics, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS

  Publication Year:2024

  Volume:55

  Issue:5

  Start Page:625

  End Page:636

  DOI Link:http://dx.doi.org/10.1002/jrs.6657

  数据库ID（收录号）:WOS:001152336300001
• Record 330 of
  
  Title:Inverse design of high efficiency and large bandwidth power splitter for arbitrary power ratio based on deep residual network
  
  Author Full Names:Wen, Jin; Wu, Zhengwei; Zhang, Hui; Wang, Qian; Yu, Huimin; Zhang, Ying; Pan, Yu; Liu, Zhanzhi

  Source Title:OPTICAL AND QUANTUM ELECTRONICS

  Language:English

  Document Type:Article

  Abstract:In this research, we propose the deep Residual Network to realize the inverse design of a low loss 1 x 3 port power splitter with an area of 2.6 x 2.6 mu m2 on a standard silicon-on-insulator platform. Then the area is used as the inverse design region and discretized into 20 x 20 square pixels, where each pixel can be switched between the two random initial states of silicon square with and without holes. Besides, we use the direct binary search algorithm to change the state of the pixels so that the distribution of all pixels in the inverse design region reaches the optimal value of the algorithm. While training the network, inputting spectral transmission response, and using the etched hole vector positions as a label for the inverse design, it achieved an accuracy of 0.9111 and a correlation coefficient greater than 0.88 for all three ports. Finally, we demonstrated 1 x 3 power splitters with 1:2:1, 1:2:1.5, 1:3:1, and 1:3:2 distribution ratios and a more than 90% maximum transmission efficiency with bandwidth from 1450 to 1650 nm while having a low insertion loss of less than 0.45 dB. This research can be found potential applications in the design of photonic devices with high performance and small size.

  Addresses:[Wen, Jin; Wu, Zhengwei; Zhang, Hui; Wang, Qian; Yu, Huimin; Zhang, Ying; Pan, Yu; Liu, Zhanzhi] Xian Shiyou Univ, Sch Sci, Xian 710065, Peoples R China; [Wen, Jin] Chinese Acad Sci, State Key Lab Transient Opt & Photon, Xian Inst Opt & Precis Mech, Xian 710119, Peoples R China

  Affiliations:Xi'an Shiyou University; Chinese Academy of Sciences; Xi'an Institute of Optics & Precision Mechanics, CAS; State Key Laboratory of Transient Optics & Photonics

  Publication Year:2024

  Volume:56

  Issue:4

  Article Number:512

  DOI Link:http://dx.doi.org/10.1007/s11082-023-06165-x

  数据库ID（收录号）:WOS:001157385200094
• Record 331 of
  
  Title:Phase correction strategy based on structured light fringe projection profilometry
  
  Author Full Names:Cao, Hongyan; Qiao, Dayong; Yang, Di

  Source Title:OPTICS EXPRESS

  Language:English

  Document Type:Article

  Keywords Plus:UNWRAPPING ALGORITHM; WAVELET; ERROR

  Abstract:Fringe projection profilometry based on structured light has been widely used in 3-D vision due to its advantages of simple structure, good robustness, and high speed. The principle of this technique is to project multiple orders of stripes on the object, and the camera captures the deformed stripe map. Phase unwrapping and depth map calculation are important steps. Still, in actual situations, phase ambiguity is prone to occur at the edges of the object. In this paper, an adaptive phase segmentation and correction (APSC) method after phase unwrapping is proposed. In order to effectively distinguish the stable area and unstable area of the phase, a boundary identification method is proposed to obtain the structural mask of the phase. A phase compensation method is proposed to improve the phase accuracy. Finally, we obtain the 3-D reconstruction result based on the corrected phase. Specific experimental results verify the feasibility and effectiveness of this method. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

  Addresses:[Cao, Hongyan; Qiao, Dayong] Northwestern Polytech Univ, Key Lab Micro Nano Syst Aerosp, Minist Educ, Xian 710072, Peoples R China; [Cao, Hongyan; Qiao, Dayong] Northwestern Polytech Univ, Shaanxi Prov Key Lab Micro & Nano Electromech Syst, Xian 710072, Peoples R China; [Yang, Di] Chinese Acad Sci, Xian Inst Opt & Precis Mech, Xian 710119, Peoples R China

  Affiliations:Northwestern Polytechnical University; Northwestern Polytechnical University; Chinese Academy of Sciences; Xi'an Institute of Optics & Precision Mechanics, CAS

  Publication Year:2024

  Volume:32

  Issue:3

  Start Page:4137

  End Page:4157

  DOI Link:http://dx.doi.org/10.1364/OE.513572

  数据库ID（收录号）:WOS:001200073600004
• Record 332 of
  
  Title:Evaporation characteristics of Er3+-doped silica fiber and its application in the preparation of whispering gallery mode lasers
  
  Author Full Names:Li, Angzhen; Ward, Jonathan M.; Tian, Ke; Yu, Jibo; She, Shengfei; Hou, Chaoqi; Guo, Haitao; Chormaic, Sile Nic; Wang, Pengfei

  Source Title:OPTICS EXPRESS

  Language:English

  Document Type:Article

  Keywords Plus:SPECTROSCOPIC PROPERTIES; VAPOR-PRESSURE; UP-CONVERSION; GLASS; EMISSION

  Abstract:In this work, the concentration of rare-earth ions in doped silica whispering gallery lasers (WGLs) is controlled by evaporation. The fabrication of WGLs is used to experimentally evaluate the evaporation rate (mol/mu m) and ratio (mol/mol) of erbium and silica lost from a doped fiber during heating. Fixed lengths of doped silica fiber are spliced to different lengths of undoped fiber and then evaporated by feeding into the focus of a CO2 laser. During evaporation, erbium ions are precipitated in the doped silica fiber to control the erbium concentration in the remaining SiO2, which is melted into a microsphere. By increasing the length of the undoped section, a critical point is reached where effectively no ions remain in the glass microsphere. The critical point is found using the spectra of the whispering gallery modes in microspheres with equal sizes. From the critical point, it is estimated that, for a given CO2 laser power, 6.36 x 10-21 mol of Er3+ is lost during the evaporation process for every cubic micron of silica fiber. This is equivalent to 1.74 x 10-7 mol of Er3+ lost per mol of SiO2 evaporated. This result facilitates the control of the doping concentration in WGLs and provides insight into the kinetics of laser-induced evaporation of doped silica.

  Addresses:[Li, Angzhen] Tianjin Univ Technol, Sch Sci, Tianjin Key Lab Quantum Opt & Intelligent Photon, Tianjin 300384, Peoples R China; [Ward, Jonathan M.] Univ Coll Cork, Phys Dept, Cork, Ireland; [Tian, Ke; Wang, Pengfei] Harbin Engn Univ, Coll Sci, Minist Educ, Key Lab Infiber Integrated Opt, Harbin 150001, Peoples R China; [Tian, Ke; Chormaic, Sile Nic] Grad Univ, Okinawa Inst Sci & Technol, Light Matter Interact Quantum Technol Unit, Onna, Okinawa 9040495, Japan; [Yu, Jibo] Xian Inst Appl Opt, Xian 710065, Peoples R China; [She, Shengfei; Hou, Chaoqi; Guo, Haitao] Chinese Acad Sci, State Key Lab Transient Opt & Photon, Xian Inst Opt & Precis Mech, Xian 710119, Peoples R China; [Chormaic, Sile Nic] Tech Univ Chemnitz, Inst Phys, D-09107 Chemnitz, Germany

  Affiliations:Tianjin University of Technology; University College Cork; Harbin Engineering University; Okinawa Institute of Science & Technology Graduate University; Chinese Academy of Sciences; Chinese Academy of Sciences; Xi'an Institute of Optics & Precision Mechanics, CAS; State Key Laboratory of Transient Optics & Photonics; Technische Universitat Chemnitz

  Publication Year:2024

  Volume:32

  Issue:3

  Start Page:3912

  End Page:3921

  DOI Link:http://dx.doi.org/10.1364/OE.509662

  数据库ID（收录号）:WOS:001199850900003
• Record 333 of
  
  Title:Polarization-encoded 3D structured light and multifocal spot arrays generation based on metasurface
  
  Author Full Names:Zhao, Jiaqi; Ge, Suyang; Li, Yingbo; Liu, Zilei; Yang, Weihua; Li, Siqi

  Source Title:MODERN PHYSICS LETTERS B

  Language:English

  Document Type:Article

  Keywords Plus:OPTICS

  Abstract:Fluorescence microscopy possesses the advantages of high resolution, high sensitivity, molecular specificity and noninvasiveness, providing an important tool in life science research. The multifocal array and 3D structured light are two kinds of important light fields that are often used in scanning fluorescence microscopy systems and wide-field fluorescence microscopy systems. However, traditional methods for generating multifocal arrays and 3D structured light illumination rely on various bulk optical components, making it challenging to achieve compact optical systems. Besides, generating these two types of illumination typically requires two separate and independent optical systems, hindering the integration of different types of fluorescence microscopy systems. Here, a dielectric metasurface is proposed that can achieve the switching between multifocal arrays and 3D structured light through polarization state modulation, greatly simplifying the illumination optics of fluorescence microscopy systems and facilitating the integration of different types of fluorescence microscopy systems.

  Addresses:[Zhao, Jiaqi; Ge, Suyang; Li, Yingbo; Liu, Zilei; Yang, Weihua; Li, Siqi] Chinese Acad Sci, Xian Inst Opt & Precis Mech, State Key Lab Transient Opt & Photon, Xian 710119, Peoples R China; [Zhao, Jiaqi; Ge, Suyang; Li, Yingbo; Liu, Zilei] Univ Chinese Acad Sci, Beijing 100049, Peoples R China

  Affiliations:State Key Laboratory of Transient Optics & Photonics; Chinese Academy of Sciences; Xi'an Institute of Optics & Precision Mechanics, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS

  Publication Year:2024

  Volume:38

  Issue:23

  DOI Link:http://dx.doi.org/10.1142/S0217984924501860

  数据库ID（收录号）:WOS:001152582700003
• Record 334 of
  
  Title:Hidden phonon highways promote photoinduced interlayer energy transfer in twisted transition metal dichalcogenide heterostructures
  
  Author Full Names:Johnson, Amalya C.; Georgaras, Johnathan D.; Shen, Xiaozhe; Yao, Helen; Saunders, Ashley P.; Zeng, Helen J.; Kim, Hyungjin; Sood, Aditya; Heinz, Tony F.; Lindenberg, Aaron M.; Luo, Duan; da Jornada, Felipe H.; Liu, Fang

  Source Title:SCIENCE ADVANCES

  Language:English

  Document Type:Article

  Keywords Plus:ULTRAFAST CHARGE-TRANSFER; WAALS; DYNAMICS; SEPARATION; CRYSTALS; MOS2

  Abstract:Vertically stacked van der Waals (vdW) heterostructures exhibit unique electronic, optical, and thermal properties that can be manipulated by twist-angle engineering. However, the weak phononic coupling at a bilayer interface imposes a fundamental thermal bottleneck for future two-dimensional devices. Using ultrafast electron diffraction, we directly investigated photoinduced nonequilibrium phonon dynamics in MoS2/WS2 at 4 degrees twist angle and WSe2/MoSe2 heterobilayers with twist angles of 7 degrees, 16 degrees, and 25 degrees. We identified an interlayer heat transfer channel with a characteristic timescale of similar to 20 picoseconds, about one order of magnitude faster than molecular dynamics simulations assuming initial intralayer thermalization. Atomistic calculations involving phonon-phonon scattering suggest that this process originates from the nonthermal phonon population following the initial interlayer charge transfer and scattering. Our findings present an avenue for thermal management in vdW heterostructures by tailoring nonequilibrium phonon populations.

  Addresses:[Johnson, Amalya C.; Georgaras, Johnathan D.; Yao, Helen; Lindenberg, Aaron M.; Luo, Duan; da Jornada, Felipe H.] Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA; [Shen, Xiaozhe; Yao, Helen; Heinz, Tony F.; Luo, Duan] SLAC Natl Accelerator Lab, Menlo Pk, CA 94025 USA; [Saunders, Ashley P.; Zeng, Helen J.; Kim, Hyungjin; Liu, Fang] Stanford Univ, Dept Chem, Stanford, CA 94305 USA; [Sood, Aditya; Heinz, Tony F.; Lindenberg, Aaron M.] SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, Menlo Pk, CA 94025 USA; [Heinz, Tony F.] Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA; [Lindenberg, Aaron M.] SLAC Natl Accelerator Lab, Stanford PULSE Inst, Menlo Pk, CA 94025 USA; [Sood, Aditya] Princeton Univ, Dept Mech & Aerosp Engn, Princeton, NJ 08540 USA; [Sood, Aditya] Princeton Univ, Princeton Mat Inst, Princeton, NJ 08540 USA; [Luo, Duan] Chinese Acad Sci, Xian Inst Opt & Precis Mech, Key Lab Ultrafast Photoelect Diagnost Technol, Xian 710119, Peoples R China

  Affiliations:Stanford University; Stanford University; United States Department of Energy (DOE); SLAC National Accelerator Laboratory; Stanford University; Stanford University; United States Department of Energy (DOE); SLAC National Accelerator Laboratory; Stanford University; Stanford University; United States Department of Energy (DOE); SLAC National Accelerator Laboratory; Princeton University; Princeton University; Chinese Academy of Sciences; Xi'an Institute of Optics & Precision Mechanics, CAS

  Publication Year:2024

  Volume:10

  Issue:4

  Article Number:eadj8819

  DOI Link:http://dx.doi.org/10.1126/sciadv.adj8819

  数据库ID（收录号）:WOS:001185091400008
• Record 335 of
  
  Title:Fast sampling based image reconstruction algorithm for sheared-beam imaging
  
  Author Full Names:Chen, Ming-Lai; Ma, Cai-Wen; Hui, Liu; Luo, Xiu-Juan; Feng, Xu-Bin; Yue, Ze-Lin; Jing, Zhao

  Source Title:ACTA PHYSICA SINICA

  Language:Chinese

  Document Type:Article

  Abstract:Sheared-beam imaging (SBI) is an unconventional ground-based optical imaging technique. It breaksthrough the traditional optical imaging concept by using three coherent laser beams, which are laterallydisplaced at the transmit plane, to illuminate the target, reconstructing the target image from echo signals.However, the echo data sampling of the imaging system is still not fast enough to reconstruct the highresolution and clear image of the target when imaging the target that is at rapidly changing position andattitude. In order to solve this problem, in this work an image reconstruction method is proposed based on five-beam fast sampling. An emitted beam array arranged in the cross shape with a central symmetrical structure isproposed, and the encoding and decoding method of the imaging system are changed. With a single exposure,the echo signals carry more spectrum information of the target, and the number of reconstructed images can beincreased from 1 to 8, which quickly suppresses the speckle effect of the reconstructed image. Firstly, theprinciple of the imaging technique based on fast sampling is presented. Then, an image reconstruction algorithmbased on fast sampling is studied. Eight groups of phase differences and amplitude information of the target canbe extracted from echo signals. The wavefront phases are solved by the least-squares method, and wavefrontamplitude can be obtained by the algebraic operation of speckle amplitude. The target image is reconstructedby the inverse Fourier transform. The simulation results show that comparing with the traditional three-beamimage reconstruction method, the sampling times of echo data needed to obtain the same quality image arereduced from 20 to 5, which greatly reduces the sampling times of echo data and improves the sampling rate of echo data

  Addresses:[Chen, Ming-Lai; Ma, Cai-Wen; Hui, Liu; Luo, Xiu-Juan; Feng, Xu-Bin; Yue, Ze-Lin; Jing, Zhao] Chinese Acad Sci, Xian Inst Opt & Precis Mech, Xian 710119, Peoples R China; [Chen, Ming-Lai; Ma, Cai-Wen; Hui, Liu; Luo, Xiu-Juan; Feng, Xu-Bin] Chinese Acad Sci, Key Lab Space Precis Measurement Technol, Xian 710119, Peoples R China; [Chen, Ming-Lai; Ma, Cai-Wen; Hui, Liu; Luo, Xiu-Juan; Yue, Ze-Lin; Jing, Zhao] Univ Chinese Acad Sci, Beijing 100049, Peoples R China

  Affiliations:Chinese Academy of Sciences; Xi'an Institute of Optics & Precision Mechanics, CAS; Chinese Academy of Sciences; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS

  Publication Year:2024

  Volume:73

  Issue:2

  Article Number:24202

  DOI Link:http://dx.doi.org/10.7498/aps.73.20231254

  数据库ID（收录号）:WOS:001178133500019
• Record 336 of
  
  Title:Direct femtosecond laser writing fiber Bragg gratings in double-D cladding chalcogenide glass infrared fibers
  
  Author Full Names:Liu, Lutao; Li, Xingyong; Xu, Yantao; Chen, Fengyi; Xiao, Xusheng; He, Wentao; Wang, Ruohui; Zhang, Peiqing; Yu, Yongsen; Guo, Haitao

  Source Title:OPTICS AND LASER TECHNOLOGY

  Language:English

  Document Type:Article

  Keywords Plus:FABRICATION

  Abstract:Chalcogenide glass (ChG) fiber Bragg grating (FBG) is one of the key components in monolithic infrared fiber lasers and sensors. However, its effective fabrication using direct femtosecond laser writing is still seldom reported, owing to complications attributable to ChG. In this study, a double-D shaped ChG fiber was used to fabricate FBGs with high reflectivity (a 20.5 dB dip in the transmittance) and narrow 3-dB bandwidth (164 pm) using direct femtosecond laser writing. The high sensitivity to laser powers of the direct writing of the ChG FBG was revealed and understood from the perspective of the low laser-induced damage threshold of ChGs. Lowerorder reflectance of the directly written FBGs at the mid-infrared wavelength region were quantitively predicted to have higher reflectivity. These results provide a robust method of writing FBGs with arbitrary periods in ChG fibers, establishing a solid foundation for the development of infrared fiber lasers and fiber sensors.

  Addresses:[Liu, Lutao; Xu, Yantao; Xiao, Xusheng; He, Wentao; Guo, Haitao] Chinese Acad Sci, Xian Inst Opt & Precis Mech, State Key Lab Transient Opt & Photon, Xian 710119, Shaanxi, Peoples R China; [Liu, Lutao; Xu, Yantao; Xiao, Xusheng; He, Wentao; Guo, Haitao] Univ Chinese Acad Sci UCAS, Ctr Mat Sci & Optoelect Engn, Beijing 100049, Peoples R China; [Li, Xingyong; Chen, Fengyi; Wang, Ruohui] Northwest Univ, Sch Phys, Xian 710069, Shaanxi, Peoples R China; [Zhang, Peiqing] Ningbo Univ, Adv Technol Res Inst, Lab Infrared Mat & Devices, Ningbo 315211, Zhejiang, Peoples R China; [Yu, Yongsen] Jilin Univ, Coll Elect Sci & Engn, State Key Lab Integrated Optoelect, 2699 Qianjin St, Changchun 130012, Peoples R China

  Affiliations:Chinese Academy of Sciences; Xi'an Institute of Optics & Precision Mechanics, CAS; State Key Laboratory of Transient Optics & Photonics; Northwest University Xi'an; Ningbo University; Jilin University

  Publication Year:2024

  Volume:174

  Article Number:110586

  DOI Link:http://dx.doi.org/10.1016/j.optlastec.2024.110586

  数据库ID（收录号）:WOS:001170751900001