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Highly-twisted states of light from a high quality factor photonic crystal ring

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arXiv 2022年

作者： Lu, Xiyuan Wang, Mingkang Zhou, Feng Heuck, Mikkel Zhu, Wenqi Aksyuk, Vladimir A. Englund, Dirk R. Srinivasan, Kartik Microsystems and Nanotechnology Division Physical Measurement Laboratory National Institute of Standards and Technology GaithersburgMD20899 United States Joint Quantum Institute NIST University of Maryland College ParkMD20742 United States Department of Chemistry and Biochemistry 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

Twisted light with orbital angular momentum (OAM) has been extensively studied for applications in quantum and classical communications, microscopy, and optical micromanipulation. Ejecting the naturally high angular momentum whispering gallery modes (WGMs) of an optical microresonator through a grating-assisted mechanism, where the generated OAM number (l) is the difference of the angular momentum of the WGM and that of the grating, provides a scalable, chip-integrated solution for OAM generation. However, demonstrated OAM microresonators have exhibited a much lower quality factor (Q) than conventional WGM resonators (by > 100×), and an understanding of the ultimate limits on Q has been lacking. This is crucial given the importance of Q in enhancing light-matter interactions, such as single emitter coupling and parametric nonlinear processes, that underpin many important microresonator applications. Moreover, though high-OAM states are often desirable, the limits on what is achievable in a microresonator configuration are not well understood. Here, we provide new physical insight on these two longstanding questions, through understanding OAM from the perspective of mode coupling in a photonic crystal ring, and linking it to the commonly studied case of coherent backscattering between counter-propagating WGMs. In addition to demonstrating high-Q (105 to 106), high estimated OAM ejection efficiency (up to 90 %), and high-OAM number (up to l = 60), our empirical model is supported by experiments and provides a quantitative explanation for the behavior of Q and OAM ejection efficiency with l for the first time. The state-of-the-art performance and new understanding of the physics of microresonator OAM generation will open new opportunities for realizing OAM applications using chip-integrated technologies. Copyright © 2022, The Authors. All rights reserved.

关键词： Efficiency

Dynamics of multiple interacting excitatory and inhibitory populations with delays

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Physical Review E 2020年第2期102卷 022308-022308页

作者： Christopher M. Kim Ulrich Egert Arvind Kumar Bernstein Center Freiburg 79104 Freiburg Germany Biomicrotechnology IMTEK—Department of Microsystems Engineering University of Freiburg 79110 Freiburg Germany Department of Computational Science and Technology School for Electrical Engineering and Computer Science KTH Royal Institute of Technology Lindstedtsvägen 3 11428 Stockholm Sweden

A network consisting of excitatory and inhibitory (EI) neurons is a canonical model for understanding local cortical network activity. In this study, we extended the local circuit model and investigated how its dynamical landscape can be enriched when it interacts with another excitatory (E) population with long transmission delays. Through analysis of a rate model and numerical simulations of a corresponding network of spiking neurons, we studied the transition from stationary to oscillatory states by analyzing the Hopf bifurcation structure in terms of two network parameters: (1) transmission delay between the EI subnetwork and the E population and (2) inhibitory couplings that induced oscillatory activity in the EI subnetwork. We found that the critical coupling strength can strongly modulate as a function of transmission delay, and consequently the stationary state can be interwoven intricately with the oscillatory state. Such a dynamical landscape gave rise to an isolated stationary state surrounded by multiple oscillatory states that generated different frequency modes, and cross-frequency coupling developed naturally at the bifurcation points. We identified the network motifs with short- and long-range inhibitory connections that underlie the emergence of oscillatory states with multiple frequencies. Thus, we provided a mechanistic explanation of how the transmission delay to and from the additional E population altered the dynamical landscape. In summary, our results demonstrated the potential role of long-range connections in shaping the network activity of local cortical circuits.

关键词： Neuronal dynamics Neuronal network activity

High Breakdown Electric Field (> 5 MV/cm) in UWBG AlGaN Transistors

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arXiv 2025年

作者： Shin, Seungheon Pal, Hridibrata Pratt, Jon Niroula, John Zhu, Yinxuan Joishi, Chandan Klein, Brianna A. Armstrong, Andrew Allerman, Andrew A. Palacios, Tomás Rajan, Siddharth Department of Electrical & Computer Engineering The Ohio State University ColumbusOH43210 United States Department of Materials Science & Engineering The Ohio State University ColumbusOH43210 United States Microsystems Technology Laboratories Massachusetts Institute of Technology CambridgeMA02139 United States Sandia National Laboratories AlbuquerqueNM87123 United States

We report on the design and demonstration of ultra-wide bandgap (UWBG) AlGaN-channel metal-insulator heterostructure field effect transistors (HEFTs) for high-power, high-frequency applications. We find that the integration of gate dielectrics and field plates greatly improves the breakdown field in these devices, with state-of-art average breakdown field of 5.3 MV/cm (breakdown voltage > 260 V) with an associated maximum current density of 342 mA/mm, and cutoff frequency of 9.1 GHz. Furthermore, low trap-related impact was observed from minimal gate and drain lag estimated from pulsed I-V characteristics. The reported results provide the potential of UWBG AlGaN HEFTs for the next generation high-power radio frequency applications. Copyright © 2025, The Authors. All rights reserved.

关键词： Electric breakdown of solids

Geometric Criteria and Experimental Validation of the Auxetic Interval in a Three Dimensional Periodic Framework

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SSRN

SSRN 2020年

作者： Broeren, Freek G.J. Borcea, Ciprian S. Streinu, Ileana Herder, Just L. van der Wijk, Volkert Department of Precision and Microsystems Engineering Delft University of Technology Netherlands Department of Mathematics Rider University United States Computer Science Department Smith College United States

Auxetic behavior refers to lateral widening upon stretching or, in reverse, lateral shrinking upon compression. When an initially auxetic structure is actuated by compression or extension, it will not neccesarily remain auxetic for larger deformations. In this paper, we investigate the auxetic range in the deformation of a periodic framework with one degree of freedom. We use geometric criteria to identify the interval where the deformation is auxetic and validate these theoretical findings with compression experiments on sample structures with 10 × 10 × 10 unit cells. © 2020, The Authors. All rights reserved.

关键词： Deformation

App-based saccade latency and error determination across the adult age spectrum

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arXiv 2020年

作者： Lai, Hsin-Yu Saavedra-Peña, Gladynel Sodini, Charles G. Heldt, Thomas Sze, Vivienne Department of Electrical Engineering & Computer Science Massachusetts Institute of Technology CambridgeMA02139 United States Department of Electrical Engineering & Computer Science Institute for Medical Engineering & Science Microsystems Technology Laboratory Massachusetts Institute of Technology CambridgeMA02139 United States Department of Electrical Engineering & Computer Science Institute for Medical Engineering & Science Research Laboratory of Electronics Massachusetts Institute of Technology CambridgeMA02139 United States Department of Electrical Engineering & Computer Science and Research Laboratory of Electronics Massachusetts Institute of Technology CambridgeMA02139 United States

Objective: We aid in neurocognitive monitoring outside the hospital environment by enabling app-based measurements of visual reaction time (saccade latency) and error rate in a cohort of subjects spanning the adult age spectrum. Methods: We developed an iOS app to record subjects with the frontal camera during pro- and anti-saccade tasks. We further developed automated algorithms for measuring saccade latency and error rate that take into account the possibility that it might not always be possible to determine the eye movement from app-based recordings. Results: To measure saccade latency on a tablet, we ensured that the absolute timing error between on-screen task presentation and the camera recording is within 5 ms. We collected over 235,000 eye movements in 80 subjects ranging in age from 20 to 92 years, with 96% of recorded eye movements either declared good or directional errors. Our error detection code achieved a sensitivity of 0.97 and a specificity of 0.97. Confirming prior reports, we observed a positive correlation between saccade latency and age while the relationship between error rate and age was not significant. Finally, we observed significant intra- and inter-subject variations in saccade latency and error rate distributions, which highlights the importance of individualized tracking of these visual digital biomarkers. Conclusion and Significance: Our system and algorithms allow ubiquitous tracking of saccade latency and error rate, which opens up the possibility of quantifying patient state on a finer timescale in a broader population than previously possible. © 2020, CC BY.

关键词： Neurodegenerative diseases

Triggered single-photon generation and resonance fluorescence in ultra-low loss integrated photonic circuits

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arXiv 2022年

作者： Chanana, Ashish Larocque, Hugo Moreira, Renan Carolan, Jacques Guha, Biswarup Anant, Vikas Song, Jin Dong Englund, Dirk Blumenthal, Daniel J. Srinivasan, Kartik Davanco, Marcelo Microsystems and Nanotechnology Division Physical Measurement Laboratory National Institute of Standards and Technology GaithersburgMD20899 United States Institute for Research in Electronics and Applied Physics Maryland NanoCenter University of Maryland College ParkMD20742 United States Theiss Research San DiegoCA92037 United States Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA02139 United States Department of Electrical and Computer Engineering University of California Santa Barbara Santa BarbaraCA93016 United States Joint Quantum Institute NIST University of Maryland College ParkMD20742 United States Photon Spot Inc. 142 W Olive Ave MonroviaCA91016 United States Center for Opto-Electronic Convergence Systems Korea Institute of Science and Technology Seoul136-791 Korea Republic of

A central requirement for photonic quantum information processing systems lies in the combination of nonclassical light sources and low-loss, phase-stable optical modes. While substantial progress has been made separately towards ultra-low loss, ≤1 dB/m, chip-scale photonic circuits and high brightness single-photon sources, integration of these technologies has remained elusive. Here, we report a significant advance towards this goal, in the hybrid integration of a quantum emitter single-photon source with a wafer-scale, ultra-low loss silicon nitride photonic integrated circuit. We demonstrate triggered and pure single-photon emission directly into a Si3N4photonic circuit with ≈ 1 dB/m propagation loss at a wavelength of ≈ 920 nm. These losses are more than two orders of magnitude lower than reported to date for any photonic circuit with on-chip quantum emitter sources, and >50 % lower than for any prior foundry-compatible integrated quantum photonic circuit, to the best of our knowledge. Using these circuits we report the observation of resonance fluorescence in the strong drive regime, a milestone towards integrated coherent control of quantum emitters. These results constitute an important step forward towards the creation of scaled chip-integrated photonic quantum information systems. Copyright © 2022, The Authors. All rights reserved.

关键词： Photons

FeCAM: A universal compact digital and analog content addressable memory using ferroelectric

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arXiv 2020年

作者： Yin, Xunzhao Li, Chao Huang, Qingrong Zhang, Li Niemier, Michael Hu, Xiaobo Sharon Zhuo, Cheng Ni, Kai College of Information Science and Electronic Engineering Zhejiang University Hangzhou China Department of Computer Science and Engineering University of Notre Dame Notre DameIN United States Department of Microsystems Engineering Rochester Institute of Technology RochesterNY United States

Ferroelectric field effect transistors (FeFETs) are being actively investigated with the potential for in-memory computing (IMC) over other non-volatile memories (NVMs). Content Addressable Memories (CAMs) are a form of IMC that performs parallel searches for matched entries over a memory array for a given input query. CAMs are widely used for data-centric applications that involve pattern matching and search functionality. To accommodate the ever expanding data, it is attractive to resort to analog CAM for memory density improvement. However, the digital CAM design nowadays based on standard CMOS or emerging nonvolatile memories (e.g., resistive storage devices) is already challenging due to area, power, and cost penalties. Thus, it can be extremely expensive to achieve analog CAM with those technologies due to added cell components. As such, we propose, for the first time, a universal compact FeFET based CAM design, FeCAM, with search and storage functionality enabled in digital and analog domain simultaneously. By exploiting the multi-level-cell (MLC) states of FeFET, FeCAM can store and search inputs in either digital or analog domain. We perform a device-circuit co-design of the proposed FeCAM and validate its functionality and performance using an experimentally calibrated FeFET model. Circuit level simulation results demonstrate that FeCAM can either store continuous matching ranges or encode 3-bit data in a single CAM cell. When compared with the existing digital CMOS based CAM approaches, FeCAM is found to improve both memory density by 22.4× and energy saving by 8.6/3.2× for analog/digital modes, respectively. In the CAM-related application, our evaluations show that FeCAM can achieve 60.5×/23.1× saving in area/search energy compared with conventional CMOS based CAMs. Copyright © 2020, The Authors. All rights reserved.

关键词： Associative storage

Editorial: Focus on organic materials, bio-interfacing and processing in neuromorphic computing and artificial sensory applications

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Neuromorphic Computing and Engineering 2023年第4期3卷 040202-040202页

作者： van de Burgt, Yoeri Santoro, Francesca Tee, Benjamin Alibart, Fabien Institute for Complex Molecular Systems Eindhoven University of Technology Eindhoven Netherlands Microsystems Department of Mechanical Engineering Eindhoven University of Technology Eindhoven Netherlands Faculty of Electrical Engineering and IT RWTH Aachen Aachen Germany Institute of Biological Information Processing—Bioelectronics Forschungszentrum Juelich Germany Department of Materials Science and Engineering (MSE) National University of Singapore Singapore Singapore Department of Electrical and Computer Engineering (ECE) National University of Singapore Singapore Singapore Institut Interdisciplinaire d’Innovation Technologique (3IT) Universiteé de Sherbrooke Sherbrooke Canada Laboratoire Nanotechnologies Nanosystèmes (LN2) CNRS UMI-3463 Universiteé de Sherbrooke Sherbrooke Canada Institute of Electronics Microelectronics and Nanotechnology (IEMN) Universiteé de Lille Villeneuve d’Ascq France

Volatile MoS2 Memristors with Lateral Silver Ion Migration for Artificial Neuron Applications

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arXiv 2024年

作者： Cruces, Sofia Ganeriwala, Mohit D. Lee, Jimin Völkel, Lukas Braun, Dennis Grundmann, Annika Ran, Ke Marín, Enrique G. Kalisch, Holger Heuken, Michael Vescan, Andrei Mayer, Joachim Godoy, Andrés Daus, Alwin Lemme, Max C. Chair of Electronic Devices RWTH Aachen University Otto-Blumenthal-Str. 25 Aachen52074 Germany Department of Electronics and Computer Science Universidad de Granada Avenida de la Fuente Nueva S/N Granada18071 Spain Compound Semiconductor Technology RWTH Aachen University Sommerfeldstr. 18 Aachen52074 Germany Central Facility for Electron Microscopy RWTH Aachen University Ahornstr. 55 Aachen52074 Germany Forschungszentrum Jülich GmbH Wilhelm-Johnen-Str. Jülich52425 Germany AIXTRON SE Dornkaulstr. 2 Herzogenrath52134 Germany Sensors Laboratory Department of Microsystems Engineering Georges-Köhler-Allee 103 Freiburg79110 Germany AMO GmbH Advanced Microelectronic Center Aachen Otto-Blumenthal-Str. 25 Aachen52074 Germany

Layered two-dimensional (2D) semiconductors have shown enhanced ion migration capabilities along their van der Waals (vdW) gaps and on their surfaces. This effect can be employed for resistive switching (RS) in devices for emerging memories, selectors, and neuromorphic computing. To date, all lateral molybdenum disulfide (MoS2)-based volatile RS devices with silver (Ag) ion migration have been demonstrated using exfoliated, single-crystal MoS2 flakes requiring a forming step to enable RS. Here, we present volatile RS with multilayer MoS2 grown by metal-organic chemical vapor deposition (MOCVD) with repeatable forming-free operation. The devices show highly reproducible volatile RS with low operating voltages of approximately 2 V and fast switching times down to 130 ns considering their micrometer-scale dimensions. We investigate the switching mechanism based on Ag ion surface migration through transmission electron microscopy, electronic transport modeling, and density functional theory. Finally, we develop a physics-based compact model and explore the implementation of our volatile memristors as artificial neurons in neuromorphic systems. © 2024, CC BY-NC-ND.

关键词： Van der Waals forces