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IEEE International Symposium on Power Electronics for Distributed Generation Systems (PEDG)

作者： Nirajman Shrestha Sudip K. Mazumder Lars voss Laboratory for Energy and Switching-Electronics Systems University of Illinois at Chicago (UIC) Chicago IL Materials Engineering Division Lawrence Livermore National Laboratory Livermore CA

A novel high voltage optically triggered SiC Junction Field Effect Transistor (JFET) configuration is proposed. The electrical and switching characteristics of the device is studied theoretically by solving the experimentally validated transport and physical models and do analysis experimentally. The optical signal trigger low-voltage optically controlled GaAs switch, called optically triggered power transistor (OTPT), is designed for voltage rating of nearly 70 v. The OTPT is connected in series with normally-on SiC JFET to handle the current switching. The simulation result found that the optically triggered SiC JFET operated with very high blocking voltage of 1200 v and rate of current rise (di/dt) of 25 A/ns at 500 v drain bias with significantly low leakage current of 10 μA. Additionally, it is found that the current of the optically triggered JFET increases with the increase of optical power of illuminated laser. Furthermore, the experimental outcome of turn on and turn off time of the device studied at comparatively low drain bias (200 v) are 95 nm and 740 ns respectively. Finally, very high breakdown voltage and high rate of current rise leads the SiC optical JFET a potential candidate for high power switching application.

关键词： Silicon carbide optical design optical switches optical variables measurement Power electronics JFETs Delays

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current-driven optical response of plasmonic crystal: From dissipation to amplification 18

Current-driven optical response of plasmonic crystal: From d...

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Plasmonics: design, Materials, Fabrication, Characterization, and Applications XvIII 2020

作者： Gorbenko, Ilya v. Kachorovskii, valentin Y. Knap, Wojciech Ioffe Institute St. Petersburg194021 Russia ITMO University St. Petersburg19710 Russia CENTERA Laboratories Institute of High Pressure Physics PAS Warsaw01-142 Poland

ISBN: (纸本)9781510637306

We study optical response of a plasmonic crystal based on multi-gated 2D structure with periodic modulation of the electron density in the device channel. In such a structure, the plasma wave velocity is periodically modulated as well. We consider the simplest model of periodically alternating stripes of the electron density and plasma wave velocity: active regions with high plasma wave velocity and passive regions with low plasma wave velocity. Terahertz radiation applied to such a structure excites plasmonic resonances both in the active and passive stripes. The width of the resonances is determined by the momentum relaxation rate. For sufficiently large relaxation rates, the resonances in the passive regions strongly overlap and only "active resonances"survive. In this regime, the plasmonic oscillations in the active regions exponentially decay into the passive regions, so that different active regions are disconnected at plasmonic frequencies but connected at zero dc frequency. We assume that dc current is applied to this plasmonic crystal and calculate radiation-induced correction to the dissipation in the channel. We demonstrate that with increasing the dc current this correction changes sign, which results in amplification of the optical signal. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： Amplification

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Power Losses in the Front Transparent Conductive Oxide Layer of Silicon Heterojunction Solar Cells: design Guide for Single-Junction and Four-Terminal Tandem Applications

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IEEE JOURNAL OF PHOTOvOLTAICS 2020年第2期10卷 326-334页

作者： Leilaeioun, Mehdi (Ashling) Onno, Arthur Manzoor, Salman Shi, Jianwei Fisher, Kathryn C. Yu, Zhengshan J. Holman, Zachary C. Arizona State Univ Sch Elect Comp & Energy Engn Tempe AZ 85287 USA

In silicon heterojunction solar cells, optimization of the front transparent conductive oxide (TCO) layer is required in order to minimize both electrical and optical losses. In this article, design guidelines for this overall power loss minimization are presented-extending previous TCO optimization work that was limited to the maximization of the short-circuit current density alone-and these are used to prescribe the best TCOs for both single-junction and silicon-based four-terminal tandem applications. The employed procedure determines the loss associated with the front TCO layer as a function of the TCO carrier density, mobility, and thickness, as well as the pitch between the front electrode fingers. For a representative indium tin oxide (ITO) film with a mobility of approximately 20 cm(2)center dot v-1 center dot s(-1) and a carrier density of 2.5 x 10(20) cm(-3), the loss over the 700-1200 nm infrared wavelength range-the spectrum reaching the silicon bottom cell in a typical tandem structure-is minimized by using a finger pitch of 3 mm and an ITO thickness of 100-110 nm. This compares with an optimal finger pitch of 2 mm and an optimal ITO thickness of 70 nm for the same cell operating as a single-junction device under full spectrum. The methodology presented can also readily be applied to TCO materials other than ITO, to a wide variety of specific four-terminal tandem architectures and, with minor modifications, to rear TCO layers.

关键词： Four-terminal infrared (IR) spectrum silicon heterojunction (SHJ) solar cells tandem solar cells transparent conductive oxide (TCO)

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Collaborative intelligence: Challenges and opportunities

arXiv

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arXiv 2021年

作者： Bajić, Ivan v. Lin, Weisi Tian, Yonghong School of Engineering Science Simon Fraser University Canada School of Computer Science and Engineering Nanyang Technological University Singapore Department of Computer Science and Technology Peking University China

This paper presents an overview of the emerging area of collaborative intelligence (CI). Our goal is to raise awareness in the signal processing community of the challenges and opportunities in this area of growing importance, where key developments are expected to come from signal processing and related disciplines. The paper surveys the current state of the art in CI, with special emphasis on signal processing-related challenges in feature compression, error resilience, privacy, and system-level design. © 2021, CC BY.

关键词： Signal processing

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Improved Charge Pump design and Ex vivo Experimental validation of CMOS 256-Pixel Photovoltaic-Powered Subretinal Prosthetic Chip

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IEEE TRANSACTIONS ON BIOMEDICAL engineering 2020年第5期67卷 1490-1504页

作者： Kuo, Po-Han Wong, Oi-Ying Tzeng, Chi-Kuan Wu, Pu-Wei Chiao, Chuan-Chin Chen, Po-Hung Chen, Po-Chun Tsai, Yueh-Chun Chu, Fang-Liang Ohta, Jun Tokuda, Takashi Noda, Toshihiko Wu, Chung-Yu Natl Chiao Tung Univ Dept Elect Engn Hsinchu 300 Taiwan Natl Chiao Tung Univ Inst Elect Hsinchu 300 Taiwan Neuron Elect Corp Zhubei Taiwan Natl Chiao Tung Univ Dept Mat Sci & Engn Hsinchu Taiwan Natl Tsing Hua Univ Inst Mol Med Inst Syst Neurosci Dept Life Sci Hsinchu Taiwan Natl Taipei Univ Technol Dept Mat & Mineral Resources Engn Taipei Taiwan Natl Tsing Hua Univ Inst Mol Med Hsinchu Taiwan Nara Inst Sci & Technol Grad Sch Mat Sci Ikoma Japan Toyohashi Univ Technol Elect Inspired Interdisciplinary Res Inst Toyohashi Aichi Japan

An improved design of CMOS 256-pixel photovoltaic-powered implantable chip for subretinal prostheses is presented. In the proposed subretinal chip, a high-efficiency fully-integrated 4x charge pump is designed and integrated with on-chip photovoltaic (Pv) cells and a 256-pixel array with active pixel sensors (APS) for image light sensing, biphasic constant current stimulators, and electrodes. Thus the Pv voltage generated by infrared (IR) light can be boosted to above 1v so that the charge injection is increased. The proposed chip adopts the 32-phase divisional power supply scheme (DPSS) to reduce the required supply current and thus the required area of the Pv cells. The proposed chip is designed and fabricated in 180-nm CMOS image sensor (CIS) technology and post-processed with biocompatible IrOx electrodes and silicone packaging. From the electrical measurement results, the measured stimulation frequency is 28.3 Hz under the equivalent electrode impedance load. The measured maximum output stimulation current is 7.1 mu A and the amount of injected charges per pixel is 7.36 nC under image light intensity of 3200 lux and IR light intensity of 100 mW/cm(2). The function of the proposed chip has been further validated successfully with the ex vivo experimental results by recording the electrophysiological responses of retinal ganglion cells (RGCs) of retinas from retinal degeneration (rd1) mice with a multi-electrode array (MEA). The measured average threshold injected charge is about 3.97 nC which is consistent with that obtained from the patch clamp recording on retinas from wild type (C57BL/6) mice with a single electrode pair.

关键词： Electrodes Retina Charge pumps Implants optical imaging optical pumping optical sensors Divisional power supply scheme photovolltaic cell multi-electrode array charge pump biocompatible package

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All-optical reflection-mode microscopic histology of unstained human tissues

All-optical reflection-mode microscopic histology of unstain...

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optical Tomography and Spectroscopy, OTS 2020

作者： Abbasi, Saad Le, Martin Ecclestone, Benjamin Abu-Sardanah, Serene Bell, Kevan Dinakaran, Deepak Bigras, Gilbert Mackey, John R. Reza, Parsin Haji PhotoMedicine Labs Systems Design Engineering University of Waterloo WaterlooONN2L 3G1 Canada illumiSonics Inc. Systems Design Engineering University of Waterloo WaterlooONN2L 3G1 Canada Department of Oncology University of Alberta EdmontonABT6G 2V1 Canada Department of Laboratory Medicine and Pathology University of Alberta EdmontonAB Canada

current methods to visualize cancer margins can be time consuming or unreliable. Employing PARS microscopy, the first non-contact reflection-mode label-free histology-like images of cellular morphology in unstained th... 详细信息

ISBN: (纸本)9781943580743

关键词： Histology

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Machine learning-assisted global optimization of photonic devices

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NANOPHOTONICS 2021年第1期10卷 371-383页

作者： Kudyshev, Zhaxylyk A. Kildishev, Alexander, v Shalaev, vladimir M. Boltasseva, Alexandra Purdue Univ Birck Nanotechnol Ctr Sch Elect & Comp Engn W Lafayette IN 47906 USA Purdue Univ Purdue Quantum Sci & Engn Inst W Lafayette IN 47906 USA US DOE QSC Oak Ridge TN 37830 USA

Over the past decade, artificially engineered optical materials and nanostructured thin films have revolutionized the area of photonics by employing novel concepts of metamaterials and metasurfaces where spatially varying structures yield tailorable "by design" effective electromagnetic properties. The current state-of-the-art approach to designing and optimizing such structures relies heavily on simplistic, intuitive shapes for their unit cells or metaatoms. Such an approach cannot provide the global solution to a complex optimization problem where metaatom shape, inplane geometry, out-of-plane architecture, and constituent materials have to be properly chosen to yield the maximum performance. In this work, we present a novel machine learning-assisted global optimization framework for photonic metadevice design. We demonstrate that using an adversarial autoencoder (AAE) coupled with a metaheuristic optimization framework significantly enhances the optimization search efficiency of the metadevice configurations with complex topologies. We showcase the concept of physics-driven compressed design space engineering that introduces advanced regularization into the compressed space of an AAE based on the optical responses of the devices. Beyond the significant advancement of the global optimization schemes, our approach can assist in gaining comprehensive design "intuition" by revealing the underlying physics of the optical performance of metadevices with complex topologies and material compositions.

关键词： machine learning metasurface optimization thermal emitter

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The InfraRed Imaging Spectrograph (IRIS) for TMT: support structure final design 4

The InfraRed Imaging Spectrograph (IRIS) for TMT: support st...

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Conference on Advances in optical and Mechanical Technologies for Telescopes and Instrumentation Iv

作者： Hoff, Brian Fitzsimmons, Joeleff Lacy, Gordon E. Dunn, Jennifer S. Herriot, Glen Crane, Jeffrey Byrnes, Peter W. G. Chalmers, Dean Andersen, David Atwood, Jenny Hardy, Tim Natl Res Council Canada Herzberg Astron & Astrophys Res Ctr 5071 West Saanich Rd Victoria BC V9E 2E7 Canada CNR Herzberg Astron & Astrophys Res Ctr 717 White Lake Rd Cawston BC V0X 1C0 Canada

ISBN: (纸本)9781510636903

The Support Structure for the Thirty Meter Telescope (TMT) Infrared Imaging Spectrograph (IRIS) consists of 18 carbon-fiber reinforced polymer (CFRP) struts, a CFRP ring and a metal interface frame. This ultra-stiff, lightweight structure suspends the five-ton IRIS Science Cryostat and Rotator below the Narrow Field Infrared Adaptive Optics System (NFIRAOS). Through comprehensive design and analysis driven by requirements for stiffness, optical alignment, adjustability, manufacturability, weight and space, much headway was made to bring this design to fruition. This work presents the current state of design, including material down-selection, adjuster design and strategies for fabrication, alignment and testing. It summarizes methodologies and simulation results examining stiffness, seismic and thermal loads and transmission of vibration between NFIRAOS and IRIS. A prototype strut is being developed and will undergo dynamic mechanical testing to characterize its performance.

关键词： Thirty Meter Telescope IRIS Instrumentation Structure Carbon Fiber Finite Element

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Technologies for large ultra-stable optical missions: current perspectives and developments at ESA 2

Technologies for large ultra-stable optical missions: curren...

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Symposium on Astronomical Optics - design, Manufacture, and Test of Space and Ground Systems II held at SPIE optical engineering + Applications Conference

作者： Hallibert, Pascal Boquet, Fabrice Deslaef, Nicolas Sechi, Gianfranco ESA ESTEC Keplerlaan 1 NL-2200 AG Noordwijk Netherlands

ISBN: (数字)9781510629264

ISBN: (纸本)9781510629257;9781510629264

The current trend for higher resolution and sensitivity for Astronomy and Earth Observation space missions is leading to larger entrance apertures for future optical payloads, often requiring challenging and ultra-stable optical performances driving the instrument design and implementation. The level of complexity for such large systems requires a multidisciplinary approach and technological developments in cross-sectorial areas such as optics, structures, pointing accuracy, control, mechanisms. We present here a range of ESA R&D developments related to future large ultra-stable optical instrument architectures, providing perspectives on the identification of enabling technologies in view of current and future optical missions as well as and a wayforward to maturity for implementation within potential future missions.

关键词： space telescopes ESA ultrastable architectures large optical instruments verification control enabling technologies

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一种利用IGBT器件寄生电感能量的暂态调节方法

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中国电机工程学报 2025年第8期45卷 3160-3171,I0025页

作者：童乐天彭晗岳乔治辛晴童乔凌强电磁技术全国重点实验室(华中科技大学) 湖北省武汉市430074 华中科技大学光学与电子信息学院湖北省武汉市430074

功率器件由于受芯片封装及电路设计的影响,存在许多寄生电感。寄生电感可能会引起门极信号振荡或者功率器件电气应力增加等问题,因此降低寄生电感是实际应用中的重要设计指标,但寄生电感不能完全被消除。因而利用功率器件中寄生电感,实... 详细信息

功率器件由于受芯片封装及电路设计的影响,存在许多寄生电感。寄生电感可能会引起门极信号振荡或者功率器件电气应力增加等问题,因此降低寄生电感是实际应用中的重要设计指标,但寄生电感不能完全被消除。因而利用功率器件中寄生电感,实现开关暂态的调控,是一种更加有效和实际的方法。文中采用分布式参数耦合提取方法,构建一个较全面的器件内部与封装的寄生电感模型,通过瞬时能量积分方法分析寄生电感上能量的交互。进一步地,提出通过能量转移支路,实现寄生电感上能量转移,并配合dvce/dt所产生位移电流的分流,实现功率器件的电压电流变化率的分别调控。所提出的技术可实现开关损耗和电气应力同时优化,无需采用高成本器件。使用该驱动于IGBT器件IKW75N60T,在400 v/60 A的双脉冲测试下,可实现电流过冲和电压过冲分别减小12.0%和14.5%,开通损耗和关断损耗分别降低4.16%和7.6%。

关键词：寄生电感能量电气应力开关损耗电压电流变化率

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