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Controlling Light Emission with Photonic Funnels

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Controlling Light Emission with Photonic Funnels

Conference on Lasers and Electro-Optics (CLEO)

作者： J. LaMountain E. Simmons A. J. Muhowski K. Li J. Xu D. Wasserman V.A. Podolskiy Department of Physics and Applied Physics University of Massachusetts Lowell Lowell MA USA Department of Electrical and Computer Engineering University of Texas Austin Austin Texas USA

We analyze the interaction between a nanoscale emitter and a photonic funnel with a metamaterial core and demonstrate that funnel structures can significantly improve out-coupling efficiency of light as compared with ... 详细信息

ISBN: (数字)9781957171050

ISBN: (纸本)9781665466660

关键词： Plasmons Nanoscale devices Metamaterials Electrooptical waveguides Photonics

2mm Continuous DOI Positioning in Arrays of Side-Coupled Crystals for a Highly Compact 100 ps FWHM CTR TOF-PET Detector Design

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2mm Continuous DOI Positioning in Arrays of Side-Coupled Cry...

IEEE Symposium on Nuclear Science (NSS/MIC)

作者： S. Pourashraf J. W. Cates D. Innes M.N. Ullah C. S. Levin Radiology Department Stanford University Stanford California United States of America Lawrence Berkeley National Laboratory Applied Nuclear Physics Program Berkeley California United States of America Bioengineering Physics and Electrical Engineering Stanford University Stanford California United States of America

ISBN: (数字)9798350388152

ISBN: (纸本)9798350388169

To achieve more accurate depth-of-interaction (DOI) response and 3D positioning of photoelectric or scattered events in our highly compact 100 ps CTR TOF-PET detector design, we have replaced a previously CPLD-based 3DPS approach with a 3D position sensitive charge-division scalable readout which better preserves our ∼100 ps FWHM CTR results. To validate the performance and compatibility of the readout with our mixed-signal TOF-PET design, we used $2 \times 4$ arrays of $3 \times 3 \times 10 \mathrm{~mm}^{3}$ LGSO crystals side-coupled to $4 \times 6$ arrays of $3 \times 3 \mathrm{~mm}^{2}$ SiPMs. By embedding this 3DPS readout in our scaled-up TOF-PET system, we resolved 3D interaction positions along the crystal array with an average 1.6 mm FWHM DOI resolution while easily preserving our 100 ps CTR and also saving the components, footprint, and subsequently the cost, power dissipation by 32% and at least 40% compared to our previous 3DPS CPLD-based and the common 3D Anger-based readouts, respectively.

关键词： Microwave integrated circuits Three-dimensional displays Costs Accuracy Semiconductor detectors Crystals Power dissipation

Multispectral Polarization-Insensitive Graphene/Silicon Guided Mode Resonance Active Metasurfaces

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arXiv 2024年

作者： Sharma, Prateeksha Oz, Dor Lampadariou, Eleftheria Doukas, Spyros Lidorikis, Elefterios Goykhman, Ilya Faculty of Electrical and Computer Engineering Technion Haifa320000 Israel Institute of Applied Physics The Faculty of Science The Center for Nanoscience and Nanotechnology The Hebrew University of Jerusalem Jerusalem91904 Israel Department of Materials Science and Engineering University of Ioannina Ioannina45110 Greece

We investigate advanced CMOS-compatible Graphene/Silicon active metasurfaces based on guided-mode resonance filters. The simulated results show a high extinction ratio (>25 dB), narrow linewidth (~1.5 nm @1550 nm), quality factor of Q~1000, and polarization-insensitive operation. By taking advantage of graphene broadband absorption, we present a multispectral operation in the MIR using simple geometrical scaling rules. We further showcase that the same device architecture can be employed for thermo-optic tuning using graphene as an integrated microheater. Our work contributes to the development of advanced broadband silicon-based active metasurfaces for tunable spectral filters and laser mirrors, optical switches, modulators, and sensors. Copyright © 2024, The Authors. All rights reserved.

关键词： Laser mirrors

Dzyaloshinskii–Moriya-type spin-spin interaction from mixed-parity superconductivity

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arXiv 2024年

作者： Ouassou, Jabir Ali Yokoyama, Takehito Linder, Jacob Department of Computer Science Electrical Engineering and Mathematical Sciences Western Norway University of Applied Sciences HaugesundNO-5528 Norway Department of Physics Tokyo Institute of Technology Tokyo Meguro152-8551 Japan Center for Quantum Spintronics Department of Physics Norwegian University of Science and Technology TrondheimNO-7491 Norway

Interacting impurity spins adsorbed on surfaces have been suggested as basic components for applications in quantum computation and spintronics. Such spins usually prefer a parallel or antiparallel configuration, but weakly non-collinear alignments are possible due to the Dzyaloshinskii–Moriya interaction (DMI) that arises in the presence of relativistic spin-orbit coupling. Here, we show that an effective Dzyaloshinskii–Moriya-type interaction (DMTI) can emerge purely from superconducting correlations without any spin-orbit interaction. We give an analytical proof and provide a numerical study which shows that DMTI arises in mixed-parity superconductors solely from the superconducting pairing. Moreover, we show that the same effect can be realized in Josephson junctions between s-wave and p-wave superconductors, where a phase bias toggles the DMTI entirely on and off. These results enable a way to engineer spin textures using superconducting order. Copyright © 2024, The Authors. All rights reserved.

关键词： Shear waves

Unextendible entanglement of quantum channels

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arXiv 2024年

作者： Singh, Vishal Wilde, Mark M. School of Applied and Engineering Physics Cornell University IthacaNY14850 United States Hearne Institute for Theoretical Physics Department of Physics and Astronomy Center for Computation and Technology Louisiana State University Baton RougeLA70803 United States School of Electrical and Computer Engineering Cornell University IthacaNY14850 United States

Quantum communication relies on the existence of high quality quantum channels to exchange information. In practice, however, all communication links are affected by noise from the environment. Here we investigate the ability of quantum channels to perform quantum communication tasks by restricting the participants to use only local operations and one-way classical communication (one-way LOCC) along with the available quantum channel. In particular, a channel can be used to distill a highly entangled state between two parties, which further enables quantum or private communication. In this work, we invoke the framework of superchannels to study the distillation of a resourceful quantum state, such as a maximally entangled state or a private state, using multiple instances of a point-to-point quantum channel. We use the idea of k-extendibility to obtain a semidefinite relaxation of the set of one-way LOCC superchannels and define a class of entanglement measures for quantum channels that decrease monotonically under such superchannels;therefore these measures, dubbed collectively the "unextendible entanglement of a channel", yield upper bounds on several communication-theoretic quantities of interest in the regimes of resource distillation and zero error. We then generalize the formalism of k-extendibility to bipartite superchannels, thus obtaining functions that are monotone under two-extendible superchannels. This allows us to analyze probabilistic distillation of ebits or secret key bits from a bipartite state when using a resourceful quantum channel. Moreover, we propose semidefinite programs to evaluate several of these quantities, providing a computationally feasible method of comparison between quantum channels for resource distillation. Copyright © 2024, The Authors. All rights reserved.

关键词： Distillation

Enhancing Epileptic Seizure Detection with EEG Feature Embeddings

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Enhancing Epileptic Seizure Detection with EEG Feature Embed...

IEEE Biomedical Circuits and Systems (BIOCAS)

作者： Arman Zarei Bingzhao Zhu Mahsa Shoaran Institute of Electrical and Micro Engineering Neuro-X Institute EPFL Lausanne Switzerland Department of Computer Science University of Maryland College Park MD USA Department of Applied and Engineering Physics Cornell University Ithaca NY USA

Epilepsy is one of the most prevalent brain disorders that disrupts the lives of millions worldwide. For patients with drug-resistant seizures, there exist implantable devices capable of monitoring neural activity, promptly triggering neurostimulation to regulate seizures, or alerting patients of potential episodes. Next-generation seizure detection systems heavily rely on high-accuracy machine learning-based classifiers to detect the seizure onset. Here, we propose to enhance the seizure detection performance by learning informative embeddings of the EEG signal. We empirically demonstrate, for the first time, that converting raw EEG signals to appropriate embeddings can significantly boost the performance of seizure detection algorithms. Importantly, we show that embedding features, which converts the raw EEG into an alternative representation, is beneficial for various machine learning models such as Logistic Regression, Multi-Layer Perceptron, Support Vector Machines, and Gradient Boosted Trees. The experiments were conducted on the CHB-MIT scalp EEG dataset. With the proposed EEG feature embeddings, we achieve significant improvements in sensitivity, specificity, and AUC score across multiple models. By employing this approach alongside an SVM classifier, we were able to attain state-of-the-art classification performance with a sensitivity of 100% and specificity of 99%, setting a new benchmark in the field.

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Stability analysis of intralayer synchronization in time-varying multilayer networks with generic coupling functions

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Physical Review E 2022年第2期105卷 024303-024303页

作者： Md. Sayeed Anwar Sarbendu Rakshit Dibakar Ghosh Erik M. Bollt Physics and Applied Mathematics Unit Indian Statistical Institute 203 B. T. Road Kolkata 700108 India Department of Mathematics Department of Electrical and Computer Engineering Department of Physics Clarkson University Potsdam New York 13699 USA

The stability analysis of synchronization patterns on generalized network structures is of immense importance nowadays. In this article, we scrutinize the stability of intralayer synchronous state in temporal multilayer hypernetworks, where each dynamic units in a layer communicate with others through various independent time-varying connection mechanisms. Here, dynamical units within and between layers may be interconnected through arbitrary generic coupling functions. We show that intralayer synchronous state exists as an invariant solution. Using fast-switching stability criteria, we derive the condition for stable coherent state in terms of associated time-averaged network structure, and in some instances we are able to separate the transverse subspace optimally. Using simultaneous block diagonalization of coupling matrices, we derive the synchronization stability condition without considering time-averaged network structure. Finally, we verify our analytically derived results through a series of numerical simulations on synthetic and real-world neuronal networked systems.

关键词： Coupled oscillators Synchronization

Carrier confinement and alloy disorder exacerbate Auger-Meitner recombination in AlGaN ultraviolet light-emitting diodes

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arXiv 2024年

作者： Pant, Nick Bushick, Kyle McAllister, Andrew Lee, Woncheol Van de Walle, Chris G. Kioupakis, Emmanouil Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Materials Science & Engineering University of Michigan Ann ArborMI48109 United States Department of Electrical Engineering & Computer Science University of Michigan Ann ArborMI48109 United States Materials Department University of California Santa BarbaraCA93106 United States

The quantum efficiency of AlGaN ultraviolet light-emitting diodes (LEDs) declines (droops) at increasing operating powers due to Auger-Meitner recombination (AMR). Using first-principles density-functional theory, we show that indirect AMR mediated by electron-phonon coupling and alloy disorder can induce bulk C coefficients as large as ∼10-31 cm6/s. Furthermore, we find that the confinement of carriers by polarization fields within quantum wells severely relaxes crystal-momentum conservation, which exacerbates the rate of AMR over radiative recombination by an order of magnitude relative to the bulk. This results in a striking decrease in quantum efficiency at high power. Suppressing polarization fields and jointly increasing the well width would greatly mitigate AMR and efficiency droop. Copyright © 2024, The Authors. All rights reserved.

关键词： Aluminum gallium nitride

Angular Profile Estimation on Phased Array Weather Radar by Maximizing Marginal Likelihood

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Angular Profile Estimation on Phased Array Weather Radar by ...

IEEE International Conference on Radar

作者： Eiichi Yoshikawa V. Chandrasekar Koji Nishimura Daichi Kitahara Yuuki Wada Tomoo Ushio Electrical and Computer Engineering Colorado State University Fort Collins CO USA Research Institute for Sustainable Humanosphere Kyoto University Uji Kyoto Japan Department of Applied Physics and Physico-Informatics Keio University Yokohama Kanagawa Japan Division of Electrical Electronic and Infocommunications Engineering Osaka University Suita Osaka Japan

ISBN: (数字)9798331539566

ISBN: (纸本)9798331539573

This paper proposes Maximum mARginal Likelihood Estimator (MARLE) for retrieving angular profile of volume targets such as precipitation on phased array weather radar. MARLE aims to achieve super resolution and unbiased estimation simultaneously, which is difficult for existing adaptive beamformers or sparse reconstruction methods. MARLE is based on maximization of a marginal likelihood which mathematically tends to produce sparse solutions to accomplish super resolution. Furthermore, the marginal likelihood is derived based on Bayes' theorem with probabilistic properties of radar observation are considered, where is no technical assumption to produce biases. We tested MARLE with simulated radar received signals and compared it with existing methods. In the simulation, angular profiles of weather measured by CSU-CHILL radar were used as reference. In addition, the other simulation supposing three targets existing closer than mainlobe width of a phased array antenna was implemented. In these simulations, MARLE successfully worked as a super resolution and unbiased estimator.

关键词： Phased arrays Meteorological radar Superresolution Estimation Reconstruction algorithms Radar antennas Probabilistic logic Bayes methods Iterative methods Tuning