检索结果-内蒙古大学图书馆

Million-Q Free Space Meta-Optical Resonator at Visible Wavelengths

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Fang, Jie Chen, Rui Sharp, David Renzi, Enrico M. Manna, Arnab Kala, Abhinav Mann, Sander A. Yao, Kan Munley, Christopher Rarick, Hannah Tang, Andrew Pumulo, Sinabu Zheng, Yuebing Menon, Vinod M. Alù, Andrea Majumdar, Arka Department of Electrical and Computer Engineering University of Washington SeattleWA98195 United States Department of Physics University of Washington SeattleWA98195 United States Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Physics Program Graduate Center City University of New York New YorkNY10016 United States Walker Department of Mechanical Engineering Texas Materials Institute The University of Texas at Austin AustinTX78712 United States Department of Materials Science and Engineering University of Washington SeattleWA98195 United States Department of Physics City College of New York New YorkNY10031 United States

High-quality (Q)-factor optical resonators with extreme temporal coherence are of both technological and fundamental importance in optical metrology1,2, continuous-wave lasing3-5, and semiconductor quantum optics6-8. Despite extensive efforts in designing high-Q resonators across different spectral regimes, the experimental realization of very large Q-factors at visible wavelengths remains challenging due to the small feature size that is sensitive to fabrication imperfections9-12, and thus is typically implemented in integrated photonics1-4,9,10. In the pursuit of free-space optics with the benefits of large space-bandwidth product and massive parallel operations13,14, here we design and fabricate a visible-wavelength etch-free metasurface with minimized fabrication defects and experimentally demonstrate a million-scale ultrahigh-Q resonance. A new laser-scanning momentum-space-resolved spectroscopy technique with extremely high spectral and angular resolution is developed to characterize the record-high Qfactor as well as the dispersion of the million-Q resonance in free space. By integrating monolayer WSe2 into our ultrahigh-Q meta-resonator, we further demonstrate laser-like highly unidirectional and narrow-linewidth exciton emission, albeit without any operating power density threshold. Under continuous-wave laser pumping, we observe pump-power-dependent linewidth narrowing at room temperature, indicating the potential of our meta-optics platform in controlling coherent quantum light-sources. Our result also holds great promise for applications like optical sensing, spectral filtering, and few-photon nonlinear optics. Copyright © 2024, The Authors. All rights reserved.

关键词： Continuous wave lasers

Internet of Things in disaster management systems: A systematic review

学校读者我要写书评

暂无评论

AIP Conference Proceedings 2023年第1期2594卷

作者： G. P. L. Barnabas H. Citrawati T. A. Santoso N. Surantha Computer Science Department BINUS Graduate Program-Master of Computer Science Bina Nusantara University Jakarta Indonesia 11480 Department of Electrical Electronic and Communication Engineering Faculty of Engineering Tokyo City University Tamazutsumi 1-28-1 Setagaya City Tokyo 158-8557 Japan

Disasters are unexpected, sudden events that may cause monumental damages to both materials and human lives. Hence, the unpredictability and destruction that follow when a disaster happens to pose a dire challenge for researchers, scientists, and governments to find ways to effectively handle the situation and flow of information when such an event strikes. The Internet of Things (IoT) presents a solution that involves using one or more mobile devices connected over the network, thus making the transfer of data and information more effective and efficient. This paper presents a holistic analysis of the state-of-the-art IoT technologies which can answer the challenge posed above, in addition to the demand for efficiency, mobility, accuracy, as well as better communications between the command center and all actors involved in disaster operations. The applications of IoT have varied for many purposes. We divide those purposes into two broad strokes of pre-disaster management and post-disaster management IoT-aided systems. For pre-disaster management, the IoT-aided systems are mostly used to predict the possible disaster that might happen using sensors placed in strategic places. Finally, for post-disaster management, the IoT-aided systems aid in improving the effectiveness and accuracy of evacuation, relief, and victim-tracking efforts.

关键词：

Multimode Ultrastrong Coupling in Three-Dimensional Photonic-Crystal Cavities

学校读者我要写书评

暂无评论

arXiv 2023年

作者： Tay, Fuyang Mojibpour, Ali Sanders, Stephen Liang, Shuang Xu, Hongjing Gardner, Geoff C. Baydin, Andrey Manfra, Michael J. Alabastri, Alessandro Hagenmüller, David Kono, Junichiro Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley–Curl Institute Rice University HoustonTX77005 United States Department of Physics and Astronomy Purdue University West LafayetteIN47907 United States Birck Nanotechnology Center Purdue University West LafayetteIN47907 United States Department of Physics and Astronomy Rice University HoustonTX77005 United States School of Electrical and Computer Engineering Purdue University West LafayetteIN47907 United States Smalley–Curl Institute Rice University HoustonTX77005 United States School of Materials Engineering Purdue University West LafayetteIN47907 United States Université de Strasbourg CNRS Strasbourg67000 France Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States

Recent theoretical studies have highlighted the role of spatially varying cavity electromagnetic fields in exploring novel cavity quantum electrodynamics (cQED) phenomena, such as the potential realization of the elusive Dicke superradiant phase transition. One-dimensional photonic-crystal cavities (PCCs), widely used for studying solid-state cQED systems, have uniform spatial profiles in the lateral plane. Three-dimensional (3D) PCCs, which exhibit discrete in-plane translational symmetry, overcome this limitation, but fabrication challenges have hindered the achievement of strong coupling in 3D-PCCs. Here, we report the realization of multimode ultrastrong coupling in a 3D-PCC at terahertz frequencies. The multimode coupling between the 3D-PCC’s cavity modes and the cyclotron resonance of a Landau-quantized two-dimensional electron gas in GaAs is significantly influenced by the spatial profiles of the cavity modes, leading to distinct coupling scenarios depending on the probe polarization. Our experimental results are in excellent agreement with a multimode extended Hopfield model that accounts for the spatial inhomogeneity of the cavity field. Guided by the model, we discuss the possible strong ground-state correlations between different cavity modes and introduce relevant figures of merit for the multimode ultrastrong coupling regime. Our findings emphasize the importance of spatially nonuniform cavity mode profiles in probing nonintuitive quantum phenomena expected for the ground states of cQED systems in the ultrastrong coupling regime. Copyright © 2023, The Authors. All rights reserved.

关键词： Electron cyclotron resonance

Caco-2 Cell-Derived Biomimetic Electrochemical Biosensor for Cholera Toxin Detection

学校读者我要写书评

暂无评论

SSRN

SSRN 2022年

作者： Kim, Yonghwan Lee, Dongtak Seo, Youngjun Jung, Hyo Gi Jang, Jae Won Park, Dongsung Kim, Insu Lee, Gyudo Hwang, Kyo Seon Kim, Seung-Hyun Lee, Sang Won Lee, Jeong Hoon Yoon, Dae Sung School of Biomedical Engineering Korea University Seoul02841 Korea Republic of Interdisciplinary Program in Precision Public Health Korea University Seoul02841 Korea Republic of Department of Clinical Pharmacology and Therapeutics College of Medicine Kyung Hee University Seoul02447 Korea Republic of Department of Biotechnology and Bioinformatics Korea University Sejong30019 Korea Republic of Interdisciplinary Graduate Program for Artificial Intelligence Smart Convergence Technology Korea University Sejong30019 Korea Republic of School of Engineering Brown University ProvidenceRI02912 United States Department of Electrical Engineering and Computer Science University of California IrvineCA92697 United States Department of Electrical Engineering Kwangwoon University Seoul01897 Korea Republic of Astrion Inc Seoul02841 Korea Republic of

Cholera is a highly contagious and lethal waterborne disease induced by an infection with Vibrio cholerae (V. cholerae) secreting cholera toxin (CTx). Cholera toxin subunit B (CTxB) from the CTx specifically binds with monosialo-tetra-hexosyl-ganglioside (GM1) found on the exterior cell membrane of an enterocyte. Owing to the pathological process of CTx, a biomimetic electrochemical biosensor (CCB) was developed by applying GM1-expressing Caco-2 cell membrane (CCM) on the electrode surface of the biosensor for CTx detection. Briefly, the electrode surface was functionalized with CCM using the vesicle fusion method. The specific binding between GM1 and CTxB on the electrode surface was verified using confocal laser scanning microscopy and atomic force microscopy. The CTxB detection performances of the CCB, including sensitivity, selectivity, and long-term stability, were determined using electrochemical impedance spectroscopy (EIS). Based on the results, the CCB had an excellent limit of detection of ~11.46 nM and a detection range spanning 100 ng/mL - 1 mg/mL. Further, the CCB had high selectivity for the CTxB compared to different interfering molecules, which are abundant constituents of intestinal fluid and fecal matter in the human body. The long-term stability of the CCBs was also verified for 3 weeks using EIS. Overall, the CCB was found to have an excellent potential for application to point-of-care and cost-effective testing for CTxB detection in developing countries. © 2022, The Authors. All rights reserved.

关键词： Electrochemical impedance spectroscopy

Optogenetic Neural Probes: Fiberless, High-Density, Artifact-Free Neuromodulation : (Invited)

学校读者我要写书评

暂无评论

Optogenetic Neural Probes: Fiberless, High-Density, Artifact...

International Electron Devices Meeting (IEDM)

作者： Eunah Ko Kanghwan Kim Mihály Vöröslakos Sungjin Oh György Buzsáki Kensall D. Wise Euisk Yoon Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI USA Center for BioMicrosystems Brain Science Institute Korea Institute of Science and Technology Seoul Korea Neuroscience Institute Langone Medical Center New York University New York NY USA Department of Biomedical Engineering University of Michigan Ann Arbor MI USA Center for Nanomedicine Institute for Basic Science (IBS) and Graduate Program of Nano Biomedical Engineering (Nano BME) Advanced Science Institute Yonsei University Seoul Korea

ISBN: (纸本)9781665489607

Evolution of “Michigan Probes” has enabled unraveling the connectivity of neurons at cellular resolution and their dynamic interaction within and across brain areas that underlie behavioral and cognitive functions. Recently, micro-LEDs were monolithically integrated for optogenetic neuromodulation at scale without requiring external optical fiber connection. The ‘hectoSTAR’ micro-LED optoelectrode features 256 recording electrodes and 128 stimulation micro-LEDs in four silicon micro-needle shanks, covering a large volume with 1.3-mm × 0.9-mm cross-sectional area located as deep as 6 mm inside the brain. Technical challenges to overcome in scaling of optogenetic probes will be discussed, followed by future direction.

关键词： Optical fibers Electrodes Brain Optogenetics Silicon Recording Optical fiber devices

Phase-induced frequency conversion and doppler effect with time-modulated metasurfaces

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Ramaccia, Davide Sounas, Dimitrios L. Alù, Andrea Toscano, Alessandro Bilotti, Filiberto Department of Engineering ROMA TRE University Via Vito Volterra 62 Rome00146 Italy Department of Electrical and Computer Engineering Wayne State University DetroitMI48202 United States Photonics Initiative Advanced Science Research Center Physics Program Graduate Center Department of Electrical Engineering City College City University of New York New YorkNY10031 United States

Metasurfaces consisting of electrically thin and densely packed planar arrays of subwavelength elements enable an unprecedented control of the impinging electromagnetic fields. Spatially modulated metasurfaces can efficiently tailor the spatial distribution of these fields with great flexibility. Similarly, time modulated metasurfaces can be successfully used to manipulate the frequency content and time variations of the impinging field. In this paper, we present time-modulated reflective metasurfaces that cause a frequency shift to the impinging radiation, thus realizing an artificial Doppler effect in a non-moving electrically thin structure. Starting from the theoretical analysis, we analytically derive the required time modulation of the surface admittance to achieve this effect, and present a realistic time-varying structure, based on a properly designed and dynamically tuned high-impedance surface. It is analytically and numerically demonstrated that the field emerging from the metasurface is up-/down-converted in frequency according to the modulation profile of the metasurface. The proposed metasurface concept, enabling a frequency modulation of the electromagnetic field "on-the-fly", may find application in telecommunication, radar, and sensing scenarios. Copyright © 2021, The Authors. All rights reserved.

关键词： Doppler effect

Combining imitation and deep reinforcement learning to accomplish human-level performance on a virtual foraging task

学校读者我要写书评

暂无评论

arXiv 2022年

作者： Giammarino, Vittorio Dunne, Matthew F. Moore, Kylie N. Hasselmo, Michael E. Stern, Chantal E. Paschalidis, Ioannis Ch. Division of Systems Engineering Boston University BostonMA02446 United States Dept. of Electrical and Computer Engineering Boston University BostonMA02446 United States Dept. of Biomedical Engineering Boston University BostonMA02215 United States Cognitive Neuroimaging Center Boston University BostonMA02215 United States Graduate Program for Neuroscience Boston University BostonMA02215 United States Center for Systems Neuroscience Boston University BostonMA02215 United States

We develop a simple framework to learn bio-inspired foraging policies using human data. We conduct an experiment where humans are virtually immersed in an open field foraging environment and are trained to collect the highest amount of rewards. A Markov Decision Process (MDP) framework is introduced to model the human decision dynamics. Then, Imitation Learning (IL) based on maximum likelihood estimation is used to train Neural Networks (NN) that map human decisions to observed states. The results show that passive imitation substantially underperforms humans. We further refine the human-inspired policies via Reinforcement Learning (RL) using the on-policy Proximal Policy Optimization (PPO) algorithm which shows better stability than other algorithms and can steadily improve the policies pretrained with IL. We show that the combination of IL and RL can match human results and that good performance strongly depends on combining the allocentric information with an egocentric representation of the environment. © 2022, CC BY.

关键词： Reinforcement learning

Vacuum Ultraviolet Light-Generating Metalens

学校读者我要写书评

暂无评论

Vacuum Ultraviolet Light-Generating Metalens

Pacific Rim Conference on Lasers and Electro-Optics (CLEO/Pacific Rim)

作者： Ming Lun Tseng Michael Semmlinger Ming Zhang Catherine Arndt Tzu-Ting Huang Jian Yang Hsin Yu Kuo Vin-Cent Su Mu Ku Chen Cheng Hung Chu Benjamin Cerjan Din Ping Tsai Peter Nordlander Naomi J. Halas Institute of Electronics National Yang Ming Chiao Tung University Hsinchu Taiwan Research Center for Applied Sciences Academia Sinica Taipei Taiwan Department of Electrical and Computer Engineering Rice University Houston Texas USA Laboratory for Nanophotonics Rice University Houston Texas USA Applied Physics Graduate Program Rice University Houston Texas USA Department of Physics and Astronomy Rice University Houston Texas USA Department of Physics National Taiwan University Taipei Taiwan Department of Electrical Engineering National United University Miaoli Taiwan Department of Electrical Engineering City University of Hong Kong Kowloon Hong Kong Department of Chemistry Rice University Houston Texas USA

Vacuum ultraviolet (VUV) light is of great importance to many applications such as photochemistry and nanolithography. In this talk, a nonlinear metalens composed of ZnO nanoantennas for VUV generation and focusing wi...

关键词：

Effects of Hydrogen on Endurance Characteristics in NAND Flash Memories

学校读者我要写书评

暂无评论

ECS Advances 2022年第4期1卷 042001-042001页

作者： Chiu, Yung-Yueh Liu, Wen-Chien Chen, Yu-Jung Kumaria, Roshni Takeshita, Toshiaki Yano, Masaru Shirota, Riichiro Department of Electrical and Computer Engineering National Yang Ming Chiao Tung University Hsinchu 300 Taiwan College of Semiconductor Research National Tsing Hua University Hsinchu 300 Taiwan EECS International Graduate Program National Yang Ming Chiao Tung University Hsinchu 300 Taiwan Winbond Electronics Corporation Kanagawa 222-0033 Japan

This study comprehensively investigates the effect of hydrogen content in forming gas annealing (FGA) on the endurance of NAND flash memories by statistically analyzing the transconductance (G_m,max) characteristics. The G_m,max degradation (ΔG_m,max) worsened with higher cycling temperature, delayed time period from erasing to programming (t_EP) operation, and higher word-line bias (V_A) during t_EP. Moreover, these effects become more pronounced as the hydrogen content in FGA increases. Using the measured G_m,max distributions and Monte -Carlo TCAD technology, the activation energy (E_A) of oxide damage creation can be extracted. The extracted E_A values were 50 meV and 160 meV for the diluted (4%) and pure (100%) hydrogen samples, respectively. This suggests that a higher hydrogen concentration results in more ionized hydrogen atoms remaining in the oxide layer. During t_EP, these hydrogen ions can drift near the Si/SiO₂ surface, where they may react to form trap states. E_A is revealed to have a linear relationship with respect to V_A, where the slope is independent of the hydrogen content in FGA. © 2022 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.

关键词：