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Research Square 2022年

作者： Chen, Zihan Li, Renjie Zhang, Zhaoyu Shenzhen Key Lab of Semiconductor Lasers School of Science and Engineering The Chinese University of Hong Kong-Shenzhen Shenzhen China

The quality (Q) factor and the mode volume are the two most important properties of optical resonances realized by Photonic Crystal (PC) nanocavities. A higher Q-factor means a stronger ability of the cavity to confine optical energy inside of itself and a smaller mode volume will lead to smaller device footprint and higher degree of integration. The traditional method to calculate the Q factor and mode volume of a PC nanocavity with a fixed design is to verify it in a simulation software. To improve the efficiency of the validation procedure, a Convolutional Neural Network (CNN) based approach has been designed to predict these two target values. In this paper, an overview of existing predictive CNN models is provided, and the hyperparameter optimization used to improve the accuracy and correlation of predictions by the model is shown. All in all, the authors propose a possible optimization strategy for the current CNN model applied in photonics forward predictions and also provide a general framework for the hyperparameter optimization of CNNs with non-image inputs and multiple outputs. © 2022, CC BY.

关键词： Computer software

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optically Multiplexed Neutron Time-of-Flight Technique for ion Temperature Imaging in Inertial Confinement Fusion

Optically Multiplexed Neutron Time-of-Flight Technique for i...

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IEEE International Conference on Plasma Science (ICOPS)

作者： L. Tafoya C. Danly C. Wilde v. Geppert-Kleinrath R. McBride Los Alamos National Laboratory P-1: Dynamic Imaging and Radiography Los Alamos New Mexico United States of America Nuclear Engineering and Radiological Sciences University of Michigan Ann Arbor Michigan United States of America

Modern experiments in laser-driven inertial confinement fusion (ICF) are susceptible to contamination of the central hotspot by high-Z material during compression that impedes thermonuclear burn. Hotspot mix can be quantified using the ion temperature distribution of the implosion given the predicted deviation between the plasma and contaminant1. but current neutron time-of-flight (nToF) diagnostics can only measure the spatially integrated temperature. This project probes the feasibility of using time multiplexed optical fibers to record nToF spectra from segmented thin scintillators, which could be used to collect a spatially resolved temperature measurement on a single photomultiplier tube (PMT). A prototype detector was constructed in which 20 optical fibers of increasing length were coupled to an EJ-262 plastic scintillator at one end and a Photek PMT210 at the other. The detector was tested on the OMEGA laser and an nToF pulse was successfully measured through all 20 channels at the expected time separations, though direct interactions of fusion products with the PMT interfered with the first 5 channels. design methodology, material selection, experimental results, and preliminary data analysis are discussed. Next steps will be aimed at applying this technique to previous work demonstrating a 1D spatially resolved ion temperature imager on OMEGA 2 ,3 to evaluate the feasibility of 2D ion temperature imaging at NIF with a cost-efficient detector.

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Analysis and design of STI-bounded Single Photon Avalanche Diode with Low Breakdown voltage 1

Analysis and Design of STI-bounded Single Photon Avalanche D...

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1st International Conference on Electronic Information Technology and Smart Agriculture, ICEITSA 2021

作者： Hao, Jianxiu Ding, Jianqun Deng, Yungui Mi, Xianwu Wang, Qingxia Li, Zhengfeng School of Electrical and Information Engineering Huaihua University Key Lab. of Intelligent Contr. Technol. for Wuling-Mountain Ecological Agriculture in Hunan Province Huaihua China The Academic Affairs Office Huaihua University Huaihua China The Center for Practical Teaching Huaihua University Huaihua China

ISBN: (纸本)9781665413008

Single photon avalanche diodes (SPADs) which are based on impact ionization effect have been widely applied to detect the ultra-weak optical signals. Conventional SPAD devices have a high breakdown voltage due to the undeveloped manufacturing processes, which causes a high power dissipation. This paper proposes a structure of single photon avalanche diode with shallow trench isolation (STI) based on MXIC 0.18 μm complementary metal oxide semiconductor (CMOS) process. A series of simulations performed by Silvaco-Technology Computer Aided design (TCAD) were done to verify the fundamental working principle about SPAD. The two-dimensional simulation results include the volt-ampere characteristics, darkcurrent, electric field distribution, current path, impact ionization distribution and spectral response curve of the SPAD device. And the simulation results demonstrate that the proposed structure has a low breakdown voltage (11.5 v). The response peak wavelength is 500 nm, which can be applied to detecting the visible light. © 2021 IEEE.

关键词： Impact ionization

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Comparison study of WO3 thin film and nanorods for smart window applications

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Materials Today: Proceedings 2023年

作者： Ashok Reddy, G.v. Naveen Kumar, K. Shetty, Hitha D. Devaraja, C. Dhananjaya, Merum Shiva prased, H.B. Guru Prakash, Nunna Girish, K.M. venugopal, A.R. Deepak, K. Hunagund, Shirajahammad M. Department of Physics Nitte Meenakshi Institute of Technology Yelahanka Karnataka Bengaluru560064 India Department of Physics Manipal Institute of Technology Bengaluru Manipal Academy of Higher Education Karnataka Manipal576104 India School of Mechanical Engineering Yeungnam University 280 Daehak-ro Gyeongsangbuk-do Gyoungsan-si38541 Korea Republic of Department of Physics Dayananda Sagar Academy of Technology and Management Bengaluru560082 India Department of Physics Brindavan College of Engineering Bengaluru560063 India Department of Physics Reva University Kattigenahalli Karnataka Bengaluru560064 India Department of Physics Nagarjuna College of Engineering and Technology Karnataka Bengaluru562164 India

The WO3 thin films were deposited at oxygen partial pressure of 8x10-4 mbar. A template-free straightforward hydrothermal method is employed to produce vertical alignment hierarchical WO3 nano-architectures on clear conducting substrates (3x2.5 cm2 in size and slides resistance 4 O). After being deposited at ambient temperature, the samples were air annealed at 400 °C for 4 h. The optical, electrochromic, surface and structural morphology behavior of the deposited material after annealing were studied using XRD, Raman, FTIR, SEM, electrochemical analyzer and Uv–visible spectrometer characterization methods. After annealing at 400 °C for 4 h in air, every characteristic peak are matched to a monoclinic (crystalline) WO3 phase. The Nano flower array achieved a considerable coloration efficiency (24.09 cm2/s) and low cathodic peak current (−2.03 mA) compare to the Tungsten trioxide thin film produced by the DC magnetron sputtering method. The vertically oriented geometry and the porosity space between the Nano flower, which improve H+ diffusion and provide a considerable contact area for charge-transfer processes, are primarily responsible for the improved electrochromic properties. © 2023

关键词： Tungsten compounds

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Narrowing Bandgap of HfS2 by Te Substitution for Short-Wavelength Infrared Photodetection

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ADvANCED optical MATERIALS 2021年第11期9卷

作者： Ye, Jiafu Liao, Ke Ge, Xun Wang, Zhen Wang, Yang Peng, Meng He, Ting Wu, Peisong Wang, Hailu Chen, Yunfeng Cui, Zhuangzhuang Gu, Yue Xu, Hangyu Xu, Tengfei Li, Qing Zhou, Xiaohao Luo, Man Li, Ning Zubair, Muhammad Wu, Feng Wang, Peng Shan, Chongxin Wang, Gang Miao, Jinshui Hu, Weida Chinese Acad Sci Shanghai Inst Tech Phys State Key Lab Infrared Phys 500 Yutian Rd Shanghai 200083 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China Chinese Acad Sci Inst Phys Beijing Natl Lab Condensed Matter Phys Beijing 100190 Peoples R China Songshan Lake Mat Lab Dongguan 523808 Guangdong Peoples R China Huazhong Univ Sci & Technol Wuhan Natl Lab Optoelect Wuhan 430074 Peoples R China Nantong Univ Jiangsu Key Lab ASIC Design Nantong 226019 Jiangsu Peoples R China Univ Chinese Acad Sci Hangzhou 310024 Peoples R China Zhengzhou Univ Sch Phys & Engn Henan Key Lab Diamond Optoelect Mat & Devices Zhengzhou 450001 Peoples R China

Infrared photodetectors are widely used in the field of remote sensing, communications, biomedical imaging, etc. Most photodetection based on 2D transition-metal dichalcogenides (TMDs) is limited to the visible (vis) to near-infrared (NIR) due to large intrinsic bandgaps (approximate to 1.2-2 ev). Here, a bandgap engineering of HfS2 by a tellurium (Te)-replacement strategy is obtained via chemical vapor transport method. The bandgap values of HfS2(1-x)Te2x decrease from 1.7 to 0.88 ev with Te composition changing from 0 to 0.095. Few-layer HfS1.81Te0.19 based field-effect transistors exhibit a high current on/off ratio of 10(6) and decent electron mobility of 12.6 cm(2) v-1 s(-1) at room temperature. The photodetectors show a responsivity of 2 A W-1 with a remarkable photocurrent of approximate to 3 mu A and a fast response speed of 8.8/75 ms at 830 nm simultaneously. Further, the response spectrum of HfS2(1-x)Te2x based photodetectors is broadened from vis to short-wavelength infrared (SWIR), covering the free-space laser communications wavelength and the second NIR region in medicine. Bandgap engineering of 2D TMDs proposed in this work offer a promising route to develop bandgap-variable 2D materials for infrared photodetection applications.

关键词： bandgap engineering HfS2 infrared photodetectors transition‐ metal dichalcogenides

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Quantifying patterns in optical micrographs of one- and two-dimensional ellipsoidal particle assemblies

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SOFT MATTER 2020年第48期16卷 10900-10909页

作者： Grebe, veronica Liu, Mingzhu Weck, Marcus NYU Mol Design Inst New York NY 10003 USA NYU Dept Chem New York NY 10003 USA

current developments in colloidal science include the assembly of anisotropic colloids with broad geometric diversity. As the complexity of particle assemblies increases, the need for ubiquitous algorithms that quantitatively analyze images of the assemblies to deliver key information such as quantification of crystal structures becomes more urgent. This contribution describes algorithms capable of image analysis for classifying colloidal structures based on abstracted interparticle relationship information and quantitatively analyzing the abundance of each structure in mixed pattern assemblies. The algorithm parameters can be adjusted, allowing for the algorithms to be adapted for different image analyses. Three different ellipsoidal particle assembly images are presented to demonstrate the effectiveness of the algorithms: a one-dimensional (1D) particle chain assembly and two two-dimensional (2D) polymorphic crystals each consisting of assemblies of two distinct plane symmetry groups. Angle relationships between neighbouring particles are calculated and neighbour counts of each particle are determined. Combining these two parameters as rules for classification criteria allows for the labeling and quantification of each particle into a defined symmetry class within an assembly. The algorithms provide a labelled image comprising classification results and particle counts of each defined class. For multiple images or individual frames from a video, the script can be looped to achieve automatic processing. The yielded classification data allow for more in-depth image analysis of mixed pattern particle assemblies. We envision that these algorithms will have utility in quantitative analysis of images comprising ellipsoidal colloidal materials, nanoparticles, or biological matter.

关键词： Image analysis

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Introducing a dynamic deep neural network to infer lens design starting points 20

Introducing a dynamic deep neural network to infer lens desi...

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Conference on current developments in Lens design and optical engineering XX

作者： Cote, Geoffroi Lalonde, Jean-Francois Thibault, Simon Univ Laval Ctr Opt Photon & Laser Quebec City PQ G1V 0A6 Canada Univ Laval Lab Vis & Syst Numer Quebec City PQ G1V 0A6 Canada

ISBN: (数字)9781510629028

ISBN: (纸本)9781510629028

Most lens design problems involve the time-consuming task of finding a proper starting point, that is, a lens design that approximately fulfills the desired first-order specifications while decently correcting aberrations. In recent work, a fully-connected (FC) deep neural network was trained to learn this task by extrapolating from known lens design databases. Here, we introduce a new dynamic neural-network architecture for the starting point problem which is based on a recurrent neural network (RNN) architecture. As we show, the dynamic network can learn to infer good starting points on many lens design structures at once whereas the previous model was limited to a given sequence of glass elements and air gaps. We also show that a pretrained RNN model can generalize its knowledge over new lens design structures for which we have no reference lens design and obtain a significantly better optical performance than a RNN trained from scratch.

关键词： Manuscript format template SPIE Proceedings LaTeX

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Functional Characterization and Testing of a Hybrid Energy Storage System Applied to Space Resources Utilization

Functional Characterization and Testing of a Hybrid Energy S...

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IAF Space Power Symposium 2021 at the 72nd International Astronautical Congress, IAC 2021

作者： Giuliani, v. Scipioni, M. Sueda, R. Department of System Engineering S.A.B. Aerospace 8 Contrada Piano Cappelle Benevento Italy Department of Mechanical Engineering S.A.B. Aerospace 8 Contrada Piano Cappelle Benevento Italy Department of Application Engineering LICAP Technologies 9795 Business Park Dr unit i SacramentoCA United States

ISBN: (纸本)9781713843092

In the last few years, the global interest in deep space missions has grown exponentially. Technological developments and studies, carried out through increasingly performing spacecrafts, have given humanity the realistic perception of being able to establish a human outpost on the surface of celestial bodies other than Earth. For this reason, several -current and future- space missions are focused on the development of key technologies to make sustainable human life on another planet possible. Therefore, the production of water and oxygen, starting from the resources available in space environments, is of fundamental importance. Many terrestrial technologies could be applied to this scope, but they shall be optimized both in terms of efficiency and performance customized, as well as in terms of design to withstand specific atmospheric and environmental conditions. Several mission concepts foresee the extraction of water and oxygen starting from elements present within the soil. Hence, excavation and manipulation devices, which require lot of instantaneous electrical power, shall be implemented into complex extraction plants. This means that conventional Electrical Power Subsystems (EPS) shall be improved, in order to provide the extraction systems with very high levels of electrical power and energy, by having mass and volumes as reduced as possible. In this context, SAB Aerospace is developing a hybrid energy storage system composed of a battery pack, characterized by high energy density;and a Lithium-Ion Capacitors (LiCs) bank, characterized by very high-power density. LiCs are a new technology for space applications, but they have higher performance compared to conventional super capacitors used in several space systems. Therefore, SAB is approaching the space qualification process for these components. In this paper, the functional characterization and the performance verification process of the hybrid system will be described. Furthermore, this innovative ener

关键词： Hybrid systems

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Radiation resistance of Hg3In2Te6near-infrared photodiodes 23

Radiation resistance of Hg3In2Te6near-infrared photodiodes

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Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XXIII 2021

作者： Skliarchuk, v. Fochuk, P. Bolotnikov, A. James, R.B. Chernivtsi National University 2 Kotsiubynskoho Str. Chernivtsi58012 Ukraine Brookhaven National Laboratory UptonNY11973 United States Savannah River Laboratory AikenSC United States

ISBN: (纸本)9781510645141

The design and technology of photodiodes manufacturing with a potential barrier as Schottky contact based on a substrate of radiation-resistant n-Hg3In2Te6 single crystal are presented. The photosensitivity of the photodetector covers the wavelength range λ≈0.6-1.6 μm at the maximum current monochromatic sensitivity Sλ≈1.15 A/wt for the λmax=1.55 μm. To study the effect of contact material on the effect of the absorbed dose of ionizing radiation, two types of photodetectors Ni/n-Hg3In2Te6/In and Cr/n-Hg3In2Te6/Cr were fabricated. A study of the effect of absorbed doses of ionizing radiation Dγ1=105, Dγ2=106 Ñ- Dγ3=107 Gray on the main parameters of photodetectors: Sλ, λmax, dark currents at forward and reverse bias, open circuit voltage, short circuit current. Photodiodes, based on mercury-indium telluride (HgInTe), showed high resistance to ionizing radiation. The best resistance to ionizing radiation was shown by Cr/HgInTe/Cr photodiodes, which slightly changed their basic parameters at the absorbed dose of Dγ3=107 Gray. Ni/HgInTe/In photodetectors lost their function after exposure to an absorbed dose of Dγ3=107 Gray. In Ni/HgInTe/In photodetectors the absorbed dose of Dγ3=107 Gray practically destroyed the indium contact. 30-50 % of nickel front contact was also destroyed. For comparison, similar studies were performed with photodetectors based on cadmium telluride Cr/CdTe/In, prepared by the authors and silicon too. As silicon-based photodetectors the industrial photodiodes were used. © COPYRIGHT SPIE.

关键词： Photodetectors

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显微集成术中光学相干断层血流造影术

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中国激光 2022年第15期49卷 119-126页

作者：张子艺俞晨阳乔依琳沈丽君程丹李鹏浙江大学光电科学与工程学院浙江杭州310027 浙江大学嘉兴研究院智能光电创新中心浙江嘉兴324000 温州医科大学附属眼视光医院杭州院区眼底病专科浙江杭州310020

提出一种集成手术显微镜的术中光学相干血流造影系统(iOCTA)来实现术中眼底视网膜血流灌注的动态监测。通过光学相干断层扫描血管造影(OCTA)系统的光路与商用手术显微镜的助手镜的成像光路耦合,实现显微镜-OCTA的系统集成,这种简捷的耦... 详细信息

提出一种集成手术显微镜的术中光学相干血流造影系统(iOCTA)来实现术中眼底视网膜血流灌注的动态监测。通过光学相干断层扫描血管造影(OCTA)系统的光路与商用手术显微镜的助手镜的成像光路耦合,实现显微镜-OCTA的系统集成,这种简捷的耦合方式便于现有手术显微镜的功能升级。采用基于逆信噪比和去相关的光学相干血流运动造影(ID-OCTA)算法,实现高信噪比的眼底微血管成像。利用该系统实现了活体兔眼的术中眼底血流灌注成像,揭示了血流灌注随眼内压的时空动态演变过程,发现急性高眼内压(60 mmHg;1 mmHg=133.32 Pa)将导致血流灌注密度值在短时间内降低至基线值的20%以下。所研制的iOCTA系统有望实现眼科手术中眼底血流灌注的实时监测,有助于外科医生客观评价手术过程和预测术后效果。

关键词：医用光学生物医学成像光学相干层析成像光学相干血流造影术中成像

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