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arXiv 2023年

作者： Faizanuddin, Syed Mohammed Chien, Ching-Hang Chan, Yao-Jui Kuo, Chia-Nung Lue, Chin Shuan Wen, Yu-Chieh Institute of Physics Academia Sinica Taipei11529 Taiwan Nano Science and Technology Program Taiwan International Graduate Program Academia Sinica Taipei11529 Taiwan Department of Engineering and System Science National Tsing Hua University Hsinchu300044 Taiwan Department of Physics National Cheng Kung University Tainan701401 Taiwan Research Center for Applied Sciences Academia Sinica Taipei11529 Taiwan

Three-dimensional topological semimetals were shown to host anomalously strong optical nonlinearity, but yet whether such enhancement can occur at their surfaces via topological boundary states remains an open question. Here we tackle this question by examining polarization-dependent rotational-anisotropy optical second harmonic generation (SHG) from transition metal dichalcogenide Dirac semimetal PdTe2. We find its reflected SHG to follow C3v surface symmetry with a time-varying intensity dictated by oxidation kinetics of the material after its surface cleavage, confirming the surface-derived origin of SHG. The complex surface nonlinear optical susceptibility tensor is fully characterized by heterodyne interferometry, unveiling a hidden giant out-of-plane response χzzz (2) (> 10.6 nm2/V or, equivalently, an effective bulk nonlinear susceptibility > 10.3 nm/V). Our results highlight the topological surfaces/interfaces as a new route toward nonlinear optical applications with released symmetry constraints, and demonstrate SHG as a viable means for in situ probing of surface chemistry of topological systems. Copyright © 2023, The Authors. All rights reserved.

关键词： Nonlinear optics

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Strong light-matter coupling in topological metasurfaces integrated with transition metal dichalcogenides 6

Strong light-matter coupling in topological metasurfaces int...

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6th International Conference on Metamaterials and Nanophotonics, METANANO 2021

作者： Sinev, Ivan Li, Mengyao Benimetskiy, Fedor Ivanova, Tatiana Kiriushechkina, Svetlana Vakulenko, Anton Guddala, Sriram Krizhanovskii, Dmitry Samusev, Anton Khanikaev, Alexander Department of Physics and Engineering ITMO University St. Petersburg Russia Department of Electrical Engineering City College of New York New YorkNY United States Physics Department City College of New York New YorkNY United States Physics Program Graduate Center of the City University of New York New YorkNY United States Department of Physics and Astronomy University of Sheffield SheffieldS3 7RH United Kingdom

Strong light-matter interactions enable unique nonlinear and quantum phenomena at moderate light intensities. Within the last years, polaritonic metasurfaces emerged as a viable candidate for realization of such regimes. In particular, planar photonic structures integrated with 2D excitonic materials, such as transition metal dichalcogenides (TMD), can support exciton polaritons – half-light half-matter quasiparticles. Here, we explore topological exciton polaritons which are formed in a suitably engineered all-dielectric topological photonic metasurface coupled to TMD monolayers. We experimentally demonstrate the transition of topological charge from photonic to polaritonic bands with the onset of strong coupling regime and confirm the presence of one-way spin-polarized edge topological polaritons. The proposed system constitutes a promising platform for photonic/solid-state interfaces for valleytronics and spintronics. © 2021 Institute of physics Publishing. All rights reserved.

关键词： Transition metals

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The Effect of Data Augmentation on the Accuracy of Fish Species Classification Using Deep Learning

The Effect of Data Augmentation on the Accuracy of Fish Spec...

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International Conference on Informatics and Computing (ICIC)

作者： Ellya Helmud Catur Edi Widodo Oky Dwi Nurhayati Doctor Information System Postgraduate Diponegoro University Semarang Indonesia Faculty of Information Technology Information Systems Study Program Atma Luhur Institute of Science and Business Pangkalpinang Indonesia Physics Department Faculty of Science and Mathematics Diponegoro University Semarang Indonesia Department of Computer Engineering Faculty of Engineering Diponegoro University Semarang Indonesia

ISBN: (数字)9798331517601

ISBN: (纸本)9798331517618

Fish image classification presents an intriguing challenge in the field of computer vision. This research aims to develop an accurate classification model to differentiate between four different fish species using a convolutional neural network. The dataset used consists of $\mathbf{3 0 1 0}$ fish images, divided into training, validation, and testing sets. The convolutional neural network model was trained both with and without data augmentation. Evaluation results show that the model trained with data augmentation achieved an accuracy of $95 \%$ with a loss value of 0.0983, slightly better than the model without augmentation which achieved an accuracy of $94.56 \%$ with a loss value of $\mathbf{0. 1 7 9 4}$. This indicates that data augmentation techniques are effective in improving model performance, likely because augmentation helps the model generalize better to variations in fish image data. The results of this research demonstrate the significant potential of convolutional neural network for fish image classification tasks. The developed model can serve as a foundation for the development of computer vision-based applications such as automatic fish species identification in fisheries or educational applications. Further research can be conducted by exploring different convolutional neural network architectures, more advanced data augmentation techniques, and larger datasets to improve model performance.

关键词： Deep learning Training Accuracy Computational modeling Computer architecture Fish Data augmentation Data models Convolutional neural networks Image classification

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Optical Spectroscopy of Excitons in ReS2 Monolayers Grown by Chemical Vapor Deposition

SSRN

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SSRN 2024年

作者： Ojo, Solomon Onasanya, Juwon Benamara, Mourad Hamad, Bothina Manasreh, M.O. Material Science and Engineering program University of Arkansas FayettevilleAR72701 United States Institute of nanotechnology University of Arkansas FayettevilleAR72701 United States Physics Department University of Arkansas FayettevilleAR72701 United States Department of Electrical Engineering and Computer Science University of Arkansas FayettevilleAR72701 United States

Monolayers of ReS2 were grown by a chemical vapor deposition technique on SiO2/Si substrates and investigated at room temperature by using μ-Raman, μ-photoluminescence (PL) and absorbance spectroscopies. The Raman scattering spectrum exhibits several phonon modes that were confirmed by the computation analysis based on the density functional theory. The ReS2 structural integrity was confirmed by using the XRD and the energy dispersion spectroscopy that was obtained by the scanning electron microscopy. Photoluminescence spectra show excitons related to interband transition in thin monolayer flakes and bulk-like structures. Additionally, a sharp PL line located at 1.2620 eV with a second harmonic peak at 2.5420 eV was observed and explained in terms of interband excitonic transitions originating within the rhenium 5d orbit. An optical absorbance spectrum with an exciton peak around 1.4660 eV was obtained for an assembly of ReS2 flakes grown on silica substrate. © 2024, The Authors. All rights reserved.

关键词： Phonons

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Advanced Under-Rails Fiber-Optic Sensor for Detection of Rolling Stock and Axles in Tram Transport

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IEEE Transactions on Instrumentation and Measurement 2025年 74卷

作者： Fajkus, Marcel Jargus, Jan Nedoma, Jan Kepak, Stanislav Krizan, Daniel Cubik, Jakub Krenzelok, Tomas Leal, Arnaldo Marques, Carlos VSB—Technical University of Ostrava Faculty of Electrical Engineering and Computer Science Department of Telecommunications Ostrava708 00 Czech Republic Prodin a.s. Pardubice530 02 Czech Republic Graduate Program in Electrical Engineering Federal University of Espirito Santo Vitoria29075-910 Brazil University of Aveiro CICECO—Aveiro Institute of Materials Physics Department Aveiro3810-193 Portugal VSB—Technical University of Ostrava Department of Physics Ostrava708 00 Czech Republic

This article describes the implementation of an advanced fiber-optic intensity sensor for the comprehensive detection of axles and bogies of rail vehicles in tram transport. The sensor uses the principle of optical fiber bending, where the intensity of transmitted light is modulated due to mechanical stress on the fiber caused by the passage of a tram and the subsequent reversible deformation of the rail. The innovative design of the sensor allows for its easy installation under the rail foot, between the rail and the sleeper, replacing conventional anti-vibration pads, and includes specially designed deformable elements which the optical fiber bends and modulates the transmitted light intensity. During long-term testing (11 months in various weather conditions) conducted in the real tram depot (Ostrava, Czech Republic), 20602 tram passages were secured and analyzed. The sensor demonstrated success in detecting bogies, achieving 100% accuracy with no false positives (FPs) or false negatives (FNs). Axle detection showed an average success rate of 86.1%, with variability among different tram types up to 97.8%. The signal modulation was also subjected to detailed analysis, revealing differences in responses between various tram types, which can be attributed to differences in bogie construction and vehicle weight. Due to its electromagnetic immunity, the implemented fiber-optic sensor offers the potential for more reliable detection and broad application possibilities, including track occupancy monitoring, speed measurement, or determining the direction of travel on single-track lines. With slight optimization, the sensor could also be used to weigh rail vehicles or as an axle counter in railway or light rail transport. © 1963-2012 IEEE.

关键词： Bogies (railroad rolling stock)

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Application of VLAB-Based STEM in the Direct Circuit Electricity Section 2

Application of VLAB-Based STEM in the Direct Circuit Electri...

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2nd International Conference on Computer, Science, engineering, and Technology, ICComSET 2019

作者： Rachmat, A. Jannati, E.D. Susandi, D. Kaniawati, I. Siahaan, P. Mechanical Engineering Study Program Universitas Majalengka Indonesia Industry Engineering Study Program Universitas Majalengka Indonesia Department of Physics Education Universitas Pendidikan Indonesia Bandung Indonesia

Our research aims to determine the results of student responses after applying VLAB-based STEM learning in the direct current electric circuit section. This study uses a qualitative method. Sampling using a purposive sampling technique. The sample consisted of 13 students of mechanical engineering study program at Universitas Majalengka. The sample consisted of 13 students of mechanical engineering study program at Universitas Majalengka.. Data collection techniques using student questionnaire responses. The results of the questionnaire were analyzed descriptively. Most students respond like VLAB-based STEM, the stages of learning provide learning experiences for students so students are motivated in learning. © 2020 Published under licence by IOP Publishing Ltd.

关键词： Students

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Polarization-driven dynamic laser speckle analysis for brain neoplasms differentiation

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Light(Advanced Manufacturing) 2024年第4期5卷 31-44页

作者： Vahid Abbasian Vahideh Farzam Rad Parisa Shamshiripour Davoud Ahmadvand Arash Darafsheh Department of Radiation Oncology Washington University School of Medicine in St.LouisSt.LouisMO 63110USA Imaging Science Program McKelvey School of EngineeringWashington University in St.LouisSt.LouisMO 63130USA Department of Physics Institute for Advanced Studies in Basic Sciences(IASBS)Zanjan 45137-66731Iran Department of Molecular Imaging Faculty of Advanced Technologies in MedicineIran University of Medical SciencesTehranIran Faculty of Medicine Iran University of Medical SciencesTehranIran

Early diagnosis of brain tumors is often hindered by non-specific symptoms,particularly in eloquent brain regions where open surgery for tissue sampling is *** limitation increases the risk of misdiagnosis due to tumor heterogeneity in stereotactic ***-free diagnostic methods,including intraoperative probes and cellular origin analysis techniques,hold promise for improving diagnostic *** offers valuable information on the polarization properties of biomedical samples,yet it may not fully reveal specific structural *** interpretative scope of polarimetric data is sometimes constrained by the limitations of existing decomposition *** the other hand,dynamic laser speckle analysis(DLSA),a burgeoning technique,not only does not account for the polarimetric attributes but also is known for tracking only the temporal activity of the dynamic *** study bridges these gaps by synergizing conventional polarimetric imaging with DLSA for an indepth examination of sample polarization *** effectiveness of our system is shown by analyzing the collection of polarimetric images of various tissue samples,utilizing a variety of adapted numerical and graphical statistical post-processing methods.

关键词： Polarimetric imaging Dynamic laser speckle analysis Cancerous tissue Brain neoplasm Label-free diagnostics

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Non-Hermitian metasurface with non-trivial topology

Non-Hermitian metasurface with non-trivial topology

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CLEO: QELS_Fundamental Science, QELS 2022

作者： Prasad, Ciril S. Yang, Frank Li, Weijian Lach, Rosemary Everitt, Henry O. Naik, Gururaj V. Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States U.S. Army DEVCOM Army Research Laboratory-South HoustonTX United States

The synergy between topology and non-Hermiticity in photonics holds potential for optical devices that are robust against defects. We demonstrate a non-Hermitian plasmonic-dielectric metasurface in the visible with no... 详细信息

ISBN: (纸本)9781557528209

关键词： Topology

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Editorial for advanced energy storage and conversion materials and technologies

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Rare Metals 2020年第9期39卷 967-969页

作者： Jian-Min Ma Yu-Tao Li School of Physics and Electronics Hunan UniversityChangsha 410082China Materials Science and Engineering Program and Texas Materials Institute The University of Texas at AustinAustinTX 78712USA

Energy storage and conversion technologies have attracted increasing attention from academic and industrial communities due to the large demands from wide-ranging *** and developing high-performance electrode materials are cruciual to improve the performance of energy storage and conversion *** present,various energy storage and conversion devices,i.e.,potassium-ion batteries(PIBs).

关键词： energy potassium electrode

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Mid-IR Gain of Tensile Germanium Waveguide Lasers with SiNx Stress Liners

Mid-IR Gain of Tensile Germanium Waveguide Lasers with SiNx ...

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2021 IEEE Photonics Society Summer Topicals Meeting Series, SUM 2021

作者： Reza, Md Shamim Gulyas, Istvan Wistey, Mark A. Materials Science Engineering and Commercialization Program Texas State University San MarcosTX78666 United States Department of Physics Texas State University San MarcosTX78666 United States

ISBN: (纸本)9781665416009

We used ab-initio and finite element strain modeling to explain high threshold current densities in reported tensile Ge lasers. Anisotropic strains improve carrier confinement but reduces optical confinement, and intervalence band absorption still dominates. Strain anisotropy increases Jth compared with simple slab models. © 2021 IEEE.

关键词： Germanium

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