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3D Printed, Quadrupole Mass Filter with High Filter Resolution for Detecting Carbon-13 Isotopes

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3D Printed, Quadrupole Mass Filter with High Filter Resoluti...

International Conference on Vacuum Nanoelectronics (IVNC)

作者： Colin C. Eckhoff Hyeonseok Kim Luke J. Metzler Randall E. Pedder Luis Fernando Velásquez-García Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA Department of Mechanical Engineering Massachusetts Institute of Technology Cambridge MA USA Ardara Technologies LP Ardara PA USA Microsystems Technology Laboratories Massachusetts Institute of Technology Cambridge MA USA

We report the design, fabrication, and characterization of additively manufactured quadrupole mass filters with sufficient resolution and sensitivity to detect carbon-13 isotopes. This is a new milestone for 3D-printe... 详细信息

ISBN: (数字)9798350379761

ISBN: (纸本)9798350379778

关键词： Fabrication Filters Three-dimensional displays Sensitivity Mass spectroscopy Isotopes Nanoelectronics

AI-toolbox: A C++ library for reinforcement learning and planning (with Python Bindings)

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Journal of Machine Learning Research 2020年第1期21卷 1-12页

作者： Bargiacchi, Eugenio Roijers, Diederik M. Nowé, Ann Department of Computer Science Vrije Universiteit Brussel Brussels Belgium Microsystems Technology HU University of Applied Sciences Utrecht Netherlands Department of Computer Science Vrije Universiteit Brussel Belgium

This paper describes AI-Toolbox, a C++ software library that contains reinforcement learning and planning algorithms, and supports both single and multi agent problems, as well as partial observability. It is designed for simplicity and clarity, and contains extensive documentation of its API and code. It supports Python to enable users not comfortable with C++ to take advantage of the library’s speed and functionality. AI-Toolbox is free software, and is hosted online at https://***/Svalorzen/AI-Toolbox. © 2020 Eugenio Bargiacchi, Diederik M. Roijers and Ann Nowé.

关键词： Reinforcement learning

Orbital angular momentum emission from a high quality factor photonic crystal ring

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Orbital angular momentum emission from a high quality factor...

2023 Conference on Lasers and Electro-Optics, CLEO 2023

作者： Lu, Xiyuan Wang, Mingkang Zhou, Feng Heuck, Mikkel Zhu, Wenqi Aksyuk, Vladimir A. Englund, Dirk R. Srinivasan, Kartik Microsystems and Nanotechnology Division NIST GaithersburgMD20899 United States Joint Quantum Institute University of Maryland College ParkMD20742 United States Department of Electrical and Photonics Engineering Technical University of Denmark Kgs. Lyngby2800 Denmark Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA02139 United States

We provide quantitative understanding of orbital angular momentum (OAM) emission for whispering gallery modes in a microring, and achieve high-Q (105 to 106), high ejection efficiency (up to 90 %), and high-OAM number... 详细信息

ISBN: (纸本)9781957171258

关键词： Whispering gallery modes

The graphene squeeze-film microphone

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arXiv 2024年

作者： Abrahams, M.P. Martinez, J. Steeneken, P.G. Verbiest, G.J. Department of Precision and Microsystems Engineering Delft University of Technology Mekelweg 2 Delft2628 CD Netherlands Multimedia Computing Group Intelligent Systems Department Faculty of Electrical Engineering Mathematics and Computer Science Delft University of Technology Delft2628 XE Netherlands

Most microphones operate by detecting the sound-pressure induced motion of a membrane. In contrast, here we introduce a microphone that operates by monitoring the sound-pressure-induced modulation of the compressibility of air. By driving a graphene membrane at its resonance frequency, the gas, that is trapped in a squeeze-film beneath it, is compressed at high frequency. Since the stiffness of the gas film depend on the air pressure, the resonance frequency of the graphene is modulated by variations in sound pressure. We demonstrate that this squeeze-film microphone principle can be used to detect sound and music by tracking the membrane's resonance frequency using a phase-locked loop (PLL). Since the sound detection principle is different from conventional devices, the squeeze-film microphone potentially offers advantages like increased dynamic range, and a lower susceptibility to pressure-induced failure and vibration-induced noise. Moreover, it might be made much smaller, as demonstrated by the microphone in this work that operates using a circular graphene membrane with an area that is more than a factor 1000 smaller than that of MEMS microphones. Copyright © 2024, The Authors. All rights reserved.

关键词： Graphene

Strong Long-Wave Infrared Optical Response in a Topological Semiconductor with a Mexican Hat Band Structure

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arXiv 2025年

作者： Polking, Mark J. Xu, Haowei Sankar, Raman Grossklaus, Kevin Li, Ju Advanced Materials and Microsystems Group Massachusetts Institute of Technology Lincoln Laboratory 02421 United States Department of Nuclear Science and Engineering Massachusetts Institute of Technology 02139 United States Institute of Physics Academia Sinica 11529 Taiwan Department of Electrical and Computer Engineering Tufts University 02155 United States Department of Materials Science and Engineering Massachusetts Institute of Technology 02139 United States

Light sources and photodetectors operating in the far- to mid-infrared (FIR/MIR) band (8-12 μm, 0.1-0.15 eV) remain relatively poorly developed compared to their counterparts operating in the visible and near-infrared ranges, despite extensive application potential for thermal imaging, standoff sensing, and other technologies. This is attributable in part to the lack of narrow-gap materials (10 larger than that of HgxCd1-xTe (MCT), the dominant material for FIR/MIR photodetectors. A previous theoretical investigation indicated that chalcogen p and metal d band inversion in this material creates a Mexican hat band structure (MHBS), which results in a dramatic increase in the joint density of states at the optical transition edge compared to typical semiconductors. This prediction is experimentally validated here using single-crystal specimens of Pb0.7Sn0.3Se measured using temperature-dependent spectroscopic ellipsometry over a wavelength range of 1.7-20 μm (0.73-0.062 eV). These measurements demonstrate a large enhancement in extinction coefficient and refractive index characteristic of a MHBS in the vicinity of the absorption edge, in agreement with theoretical predictions. The realization of topological semiconductors with a MHBS is expected to lead to high-efficiency detectors operating in the FIR/MID range. © 2025, CC BY.

关键词： Single crystals

AC4MPC: Actor-Critic Reinforcement Learning for Nonlinear Model Predictive Control

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arXiv 2024年

作者： Reiter, Rudolf Ghezzi, Andrea Baumgärtner, Katrin Hoffmann, Jasper McAllister, Robert D. Diehl, Moritz University of Freiburg Freiburg79110 Germany The Department of Computer Science University of Freiburg Freiburg79110 Germany The Delft Center for Systems and Control Delft University of Technology Delft2628 Netherlands The Department of Microsystems Engineering The Department of Mathematics University of Freiburg Freiburg79110 Germany

Nonlinear model predictive control (MPC) and reinforcement learning (RL) are two powerful control strategies with, arguably, complementary advantages. In this work, we show how actor-critic RL techniques can be leveraged to improve the performance of MPC. The RL critic is used as an approximation of the optimal value function, and an actor roll-out provides an initial guess for primal variables of the MPC. A parallel control architecture is proposed where each MPC instance is solved twice for different initial guesses. Besides the actor roll-out initialization, a shifted initialization from the previous solution is used. Thereafter, the actor and the critic are again used to approximately evaluate the infinite horizon cost of these trajectories. The control actions from the lowest-cost trajectory are applied to the system at each time step. We establish that the proposed algorithm is guaranteed to outperform the original RL policy plus an error term that depends on the accuracy of the critic and decays with the horizon length of the MPC formulation. Moreover, we do not require globally optimal solutions for these guarantees to hold. The approach is demonstrated on an illustrative toy example and an automated driving (AD) overtaking scenario. © 2024, CC BY-NC-ND.

关键词： Dynamic programming

Provable Routing Analysis of Programmable Photonics

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arXiv 2023年

作者： Gao, Zhengqi Chen, Xiangfeng Zhang, Zhengxing Lai, Chih-Yu Chakraborty, Uttara Bogaerts, Wim Boning, Duane S. Microsystems Technology Laboratories Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA02139 United States Ghent University - IMEC Department of Information Technology Gent Belgium Center of Nano- and Biophotonics Ghent University Gent Belgium

Programmable photonic integrated circuits (PPICs) are an emerging technology recently proposed as an alternative to custom-designed application-specific integrated photonics. Light routing is one of the most important functions that need to be realized on a PPIC. Previous literature has investigated the light routing problem from an algorithmic or experimental perspective, e.g., adopting graph theory to route an optical signal. In this paper, we also focus on the light routing problem, but from a complementary and theoretical perspective, to answer questions about what is possible to be routed. Specifically, we demonstrate that not all path lengths (defined as the number of tunable basic units that an optical signal traverses) can be realized on a square-mesh PPIC, and a rigorous realizability condition is proposed and proved. We further consider multi-path routing, where we provide an analytical expression on path length sum, upper bounds on path length mean/variance, and the maximum number of realizable paths. All of our conclusions are proven mathematically. Illustrative potential optical applications using our observations are also presented. © 2023 Optica Publishing Group Copyright © 2023, The Authors. All rights reserved.

关键词： Graph theory

Optical Microresonators feature issue introduction

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Photonics Research 2023年第12期11卷 I0001-I0003页

作者： YUN-FENG XIAO KARTIK SRINIVASAN PASCAL DEL’HAYE MENGJIE YU Frontiers Science Center for Nano-optoelectronics and State Key Laboratory for Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China Microsystems and Nanotechnology Division Physical Measurement LaboratoryNational Institute of Standards and TechnologyGaithersburgMaryland 20899USA Max Planck Institute for the Science of Light 91058 ErlangenGermany Ming Hsieh Department of Electrical and Computer Engineering University of Southern CaliforniaLos AngelesCalifornia 90089USA

Optical microresonators,which confine light in both the spatial and time domains,have advanced various research areas benefiting from significantly enhanced light-matter interactions,including integrated microlasers,nonlinear frequency conversion,Kerr frequency combs,and *** the past five years,the research interests in optical microresonators have rapidly expanded and combined with other disciplines,for example,optical chaos,non-Hermitian physics,and quantum *** cutting-edge research works have enabled the creation of optical microresonators with novel properties and capabilities.

关键词： materials chaos expanded

Maximizing the Thermal Performance of Microheaters for Non-Volatile Phase Change Photonics: A Comparative Study of Pulse Width Parameter Effects 23

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Maximizing the Thermal Performance of Microheaters for Non-V...

23rd IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2024

作者： F., Vasquez-Aza H., Sun C., Lian Y.-S., Huang S.A., Vitale I., Takeuchi J., Hu N., Youngblood C.A.R., Ocampo G., Pavlidis University of Connecticut School of Mechanical Aerospace and Manufacturing Engineering StorrsCT06269 United States University of Maryland Department of Materials Science and Engineering College ParkMD20742 United States University of Maryland Institute for Research in Electronics and Applied Physics College ParkMD20742 United States Mit Lincoln Laboratory Advanced Materials and Microsystems Group LexingtonMA02139 United States University of Maryland Quantum Materials Center Department of Physics College ParkMD20742 United States Massachusetts Institute of Technology Department of Materials & Science Engineering CambridgeMA02139 United States The University of Pittsburgh Electrical & Computer Engineering Department PittsburghPA15213 United States

ISBN: (数字)9798350364330

ISBN: (纸本)9798350364330

Guiding, manipulating, and detecting light is integral to modern photonic systems that can be designed for displays, memory, data transfer, and sensors. The prospect of realizing programmable yet zero-static power photonics has recently gained attention thanks to the rise of optical phase change materials (PCMs). PCMs have a unique set of properties that make them desirable for this task: nonvolatile retention and reversible switching between their amorphous and crystalline states, which, in addition, display distinct optical and electronic properties. Nonvolatile photonic devices have primarily relied on either electrical or optical switching of PCMs. Electrical switching offers effortless CMOS integration;however, it is predominantly limited to binary output. In contrast, optical switching enables accurate multilevel control but is limited in scalability. This paper studies an alternative electro-thermal approach to nonvolatile photonics by controlling the PCM phase via doped silicon microheaters. The results highlight the significance of precise spatial and temporal temperature control to ensure optimal modulation of the PCM. Specifically, this paper investigates the impact of the electric pulse width (0.2 μs to 10 μs) on the maximum temperature for two different microheater designs. High resolution (≈410 nm) transient thermoreflectance imaging (TTI) is used to measure and analyze the surface temperature distribution across each microheater under pulsed biasing. To assess the impact of varying pulse widths, this study systematically examines their effects on maximum temperature, response time, and maximum power. Shorter pulse widths ( 1 μs) provide greater thermal stability but exhibit reduced maximum temperatures due to limited current levels. The experimental results demonstrate a nonlinear relationship between the peak temperature and the power supplied at sub-steady state thermalization time scales. For the specific microheater geometry, the optimal pulse wid

关键词： Photonic integration technology