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Phase Coexistence of Ferroelectric Vortices and Classical a1/a2 Domains in PbTiO3/SrTiO3 Superlattices.

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Microscopy and Microanalysis 2018年第S1期24卷 1638-1639页

作者： Christopher T. Nelson Zijian Hong Ajay K. Yadav Anoop R. Damodaran Shang-Lin Hsu James D. Clarkson Long-Qing Chen Lane W. Martin Ramamoorthy Ramesh Materials Science & Technology Division Oak Ridge National Laboratory Oak Ridge TN USA Department of Physics University of California Berkeley CA USA Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley CA USA Department of Materials Science and Engineering Pennsylvania State University State College PA USA Department of Materials Science and Engineering University of California Berkeley CA USA School of Electrical Engineering and Computer Science UC Berkeley Berkeley California USA.

Application of Surface Plasmon Resonance Sensor with Polypyrrole Chitosan Graphene Oxide layer to Detect the Napropamide 5

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Application of Surface Plasmon Resonance Sensor with Polypyr...

5th International Conference on Fundamental and Applied sciences, ICFAS 2018

作者： Sadrolhosseini, Amir Reza Rashid, Suraya Abdul Soleimani, Hassan Shafie, Suhaidi Noor, A.S.M. Mohammadi, Ahmad Institute of Advanced Technology Universiti Putra Malaysia Serdang Selangor43400UPM Malaysia Materials Processing and Technology Laboratory Nanomaterials and Nanotechnology Group Institute of Advanced Technology Universiti Putra Malaysia Serdang Selangor43400UPM Malaysia Department of Fundamental and Applied Science Universiti Teknologi PETRONAS Seri Iskandar3175 Malaysia Department of Electrical and Electronic Engineering Faculty of Engineering Universiti Putra Malaysia Serdang Selangor43400 UPM Malaysia Faculty of Engineering Universiti Putra Malaysia Serdang Selangor43400UPM Malaysia Department of Electrical and Computer Engineering Buein Zahra Technical University Buein Zahra Qazvin Iran

A polypyrrole Chitosan Graphene Oxide (PPy-Chi/GO) composite layer was prepared using the electro-chemical method. The PPy-Chi/GO layer was used to measure the low concentration of napropamide. In this study, the PPy-Chi/GO composite layer was deposited on the gold layer side of a microscope's glass slide in different thicknesses. The morphology, thickness, roughness, and refractive index of the layer were obtained using field effect scanning electron microscopy, profilemeter, atomic force microscopy, and the surface plasmon resonance technique. The structure of the composite layer was investigated using X-Ray diffraction. The peak that were observed from X-ray diffraction was at 9.9°, corresponding to GO, and the broad peak between 25° and 27° was related to polypyrrole and chitosan. The PPy-Chi/GO layer was used to measure the concentration of napropamide dissolved in hexane in the range of 0.01 to 100 ppm using the surface plasmon resonance technique;the limitation of sensor was 0.1 ppm. © Published under licence by IOP Publishing Ltd.

关键词： Polypyrroles

A compact structure for realizing Lorentzian, Fano and EIT resonance lineshapes in a microring resonator

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arXiv 2019年

作者： Gu, Linpeng Fang, Hanlin Li, Juntao Fang, Liang Chua, Soo Jin Zhao, Jianlin Gan, Xuetao MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions Shaanxi Key Laboratory of Optical Information Technology School of Science Northwestern Polytechnical University Xi'an710072 China State Key Laboratory of Optoelectronic Materials and Technologies School of Physics Sun Yat-Sen University Guangzhou510275 China Department of Electrical and Computer Engineering National University of Singapore 4 Engineering Drive 3 Singapore117583 Singapore

Microring resonators, as a fundamental building block of photonic integrated circuits, have been well developed into numerous functional devices, whose performances are strongly determined by microring's resonance lineshapes. We propose a compact structure to reliably realize Lorentzian, Fano, and electromagnetically induced transparency (EIT) resonance lineshapes in a microring. By simply inserting two air-holes in the side-coupled waveguide of a microring, a Fabry-Perot (FP) resonance is involved to couple with microring's resonant modes, showing Lorentzian, Fano, and EIT lineshapes over one free spectral range of the FP resonance. The quality factors, extinction ratios, and slope rates in different lineshapes are discussed. At microring's specific resonant wavelength, the lineshape could be tuned among these three types by controlling the FP cavity's length. Experiment results verify the theoretical analysis well and represent Fano lineshapes with extinction ratios of about 20 dB and slope rates over 280 dB/nm. The reliably and flexibly tunable lineshapes in the compact structure have potentials to improve microring-based devices and expand their application scopes. Copyright © 2019, The Authors. All rights reserved.

关键词： Light extinction

Entangled radiofrequency-photonic sensor network

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arXiv 2019年

作者： Xia, Yi Li, Wei Clark, William Hart, Darlene Zhuang, Quntao Zhang, Zheshen James C. Wyant College of Optical Sciences University of Arizona TucsonAZ85721 United States Department of Electronic and Information Engineering Shanxi University Taiyuan030013 China Department of Materials Science and Engineering University of Arizona TucsonAZ85721 United States General Dynamics Mission Systems 8220 East Roosevelt Street ScottsdaleAZ85257 United States General Dynamics Mission Systems 9 Vreeland Road Florham ParkNJ07932 United States Department of Electrical and Computer Engineering University of Arizona TucsonAZ85721 United States

Quantum metrology [1–4] enables a measurement sensitivity below the standard quantum limit (SQL), as demonstrated in the Laser Interferometer Gravitational-wave Observatory (LIGO) [5, 6]. As a unique quantum resource, entanglement has been utilized to enhance the performance of, e.g., microscopy [7], target detection [8], and phase estimation [9]. To date, almost all existing entanglement-enhanced sensing demonstrations are restricted to improving the performance of probing optical parameters at a single sensor, but a multitude of applications rely on an array of sensors that work collectively to undertake sensing tasks in the radiofrequency (RF) and microwave spectral ranges. Here, we propose and experimentally demonstrate a reconfigurable RF-photonic sensor network comprised of three entangled sensor nodes. We show that the entanglement shared by the sensors can be tailored to substantially increase the precision of parameter estimation in networked sensing tasks, such as estimating the angle of arrival (AoA) of an RF field. Our work would open a new avenue toward utilizing quantum metrology for ultrasensitive positioning, navigation, and timing. Copyright © 2019, The Authors. All rights reserved.

关键词： Sensor nodes

Giant Valley-Zeeman splitting from spin-singlet and spin-triplet interlayer excitons in WSe2/MoSe2Heterostructure

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arXiv 2019年

作者： Wang, Tianmeng Miao, Shengnan Li, Zhipeng Meng, Yuze Lu, Zhengguang Lian, Zhen Blei, Mark Taniguchi, Takashi Watanabe, Kenji Tongay, Sefaattin Smirnov, Dmitry Shi, Su-Fei Department of Chemical and Biological Engineering Rensselaer Polytechnic Institute TroyNY12180 United States National High Magnetic Field Lab TallahasseeFL32310 United States Department of Physics Florida State University TallahasseeFL32306 United States School for Engineering of Matter Transport and Energy Arizona State University TempeAZ85287 United States National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute TroyNY12180 United States

Transition metal dichalcogenides (TMDCs) heterostructure with a type II alignment hosts unique interlayer excitons with the possibility of spin-triplet and spin-singlet states. However, the associated spectroscopy signatures remain elusive, strongly hindering the understanding of the Moiré potential modulation of the interlayer exciton. In this work, we unambiguously identify the spin-singlet and spin-triplet interlayer excitons in the WSe2/MoSe2hetero-bilayer with a 60-degree twist angle through the gate- A nd magnetic field-dependent photoluminescence spectroscopy. Both the singlet and triplet interlayer excitons show giant valley-Zeeman splitting between the K and K' valleys, a result of the large Landé g-factor of the singlet interlayer exciton and triplet interlayer exciton, which are experimentally determined to be ∼ 10.7 and ∼ 15.2, respectively, in good agreement with theoretical expectation. The PL from the singlet and triplet interlayer excitons show opposite helicities, determined by the atomic registry. Helicity-resolved photoluminescence excitation (PLE) spectroscopy study shows that both singlet and triplet interlayer excitons are highly valley-polarized at the resonant excitation, with the valley polarization of the singlet interlayer exciton approaches unity at ∼ 20 K. The highly valley-polarized singlet and triplet interlayer excitons with giant valley-Zeeman splitting inspire future applications in spintronics and valleytronics. Copyright © 2019, The Authors. All rights reserved.

关键词： Polarization

Uniformity of Multilayer Hexagonal Boron Nitride Dielectric Stacks Grown by Chemical Vapor Deposition on Platinum and Copper Substrates

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Uniformity of Multilayer Hexagonal Boron Nitride Dielectric ...

International Symposium on Physical & Failure Analysis of Integrated Circuits

作者： Fei Hui Xianhu Liang Wenjing Fang Wei Sun Leong Haozhe Wang Hui Ying Yang Yuanyuan Shi Marco A. Villena Jing Kong Mario Lanza Institute of Functional Nano & Soft Materials Soochow University Suzhou China Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge USA Pillar of Engineering Product Development Singapore University of Technology and Design Singapore Department of Materials Science and Engineering Stanford University Stanford California USA

ISBN: (纸本)9781538649305

Large-area multilayer hexagonal boron nitride (h-BN) dielectric stacks can be grown on different metallic substrates by chemical vapor deposition (CVD). The high temperatures used during the growth produce the polycrystallization of the metallic substrates (leading to different crystallographic orientations at the surface of each grain), which may influence the catalytic activity of the CVD process on different grains, as well as the properties of the h-BN stacks grown on them. In this work we compare the uniformity of multilayer h-BN dielectric stacks grown via CVD on two different metallic substrates: Pt and Cu. Our study reveals that using Pt substrates leads to h-BN thickness fluctuations from one Pt grain to another, while this effect remarkably reduced when the h-BN is grown on Cu substrates. Therefore, the use of Cu substrates seems to be more convenient for h-BN production and integration at the wafer level.

关键词： Substrates Boron Dielectrics Nonhomogeneous media Fluctuations Conductivity Chemical vapor deposition

Empty substrate integrated waveguide-fed MMW aperture-coupled patch antenna for 5G applications 12

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Empty substrate integrated waveguide-fed MMW aperture-couple...

12th European Conference on Antennas and Propagation, EuCAP 2018

作者： Khan, Zia Ullah Jilani, Syeda Fizzah Belenguer, Angel Loh, Tian Hong Alomainy, Akram School of Electronic Engineering and Computer Science Queen Mary University of London LondonE1 4NS United Kingdom Departamento de Ingeniería Eléctrica Electrónica Automática y Comunicaciones Universidad de Castilla-La Mancha Spain Engineering Materials and Electrical Science Department National Physical Laboratory TeddingtonTW11 0LW United Kingdom

ISBN: (纸本)9781785617911

This paper introduces a microstrip square patch antenna with a novel low-cost and efficient feeding mechanism for millimetre-wave frequencies targeting at 28 GHz. The radiating patch is excited by the technique of empty substrate integrated waveguide, and two different slot configurations have been examined in this regard. It has been observed that the antenna gain profile and radiation efficiency is significantly improved in both configurations as compared to the microstrip square patch antenna provided with conventional feeding. © Institution of engineering and *** Rights Reserved.

关键词： Millimeter waves

Limits on Broadband Absorption Enhancement in the Presence of Multiple Lossy materials

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arXiv 2018年

作者： Raman, Aaswath Yu, Zongfu Fan, Shanhui Department of Materials Science and Engineering University of California Los AngelesCA90049 United States Department of Electrical and Computer Engineering University of Wisconsin MadisonWI53706 United States Department of Electrical Engineering Ginzton Laboratory Stanford University StanfordCA94305 United States

Enhancing the absorption and emission of electromagnetic waves over a broad range of wavelengths is a topic of fundamental and applied interest in photonics and energy research. In the context of light trapping in solar cells, for example, significant interest in the past decade has focused on overcoming limits in the ray-optics regime with nanophotonic structures. However, many such structures, in particular plasmonic structures, or PT-symmetric systems can posses multiple materials with varying values of intrinsic loss. Here, we rigorously determine the effect of parasitic loss on the achievable absorption enhancement in arbitrary electromagnetic structures. We show that the fundamental limit of broadband absorption enhancement, even in the presence of large parasitic loss in an alternate material, can exceed conventional ray-optics limits on light trapping and absorption enhancement. We numerically verify this behavior by determining the absorption enhancement factor of a canonical system, a metal-insulator-metal waveguide, whose core is a low-index organic semiconductor, in the presence of varying intrinsic loss values in the metal. Copyright © 2018, The Authors. All rights reserved.

关键词： Plasmonics

Near, far, wherever you are: Simulations on the dose efficiency of holographic and ptychographic coherent imaging

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arXiv 2019年

作者： Du, Ming Gürsoy, Dogǎ Jacobsen, Chris Department of Materials Science Northwestern University EvanstonIL60208 United States Advanced Photon Source Argonne National Laboratory ArgonneIL60439 United States Department of Electrical Engineering and Computer Science Northwestern University EvanstonIL60208 United States Department of Physics and Astronomy Northwestern University EvanstonIL60208 United States Chemistry of Life Processes Institute Northwestern University EvanstonIL60208 United States

Different studies in x-ray microscopy have arrived at conicting conclusions about the dose efficiency of imaging modes involving the recording of intensity distributions in the near (Fresnel regime) or far (Fraunhofer regime) field downstream of a specimen. We present here a numerical study on the dose efficiency of near-field holography versus ptychography, a variant of far-field coherent diffraction imaging (CDI) involving multiple overlapping finite illumination positions. Unlike what has been reported for single-illumination CDI, we find that the quality, measured by spatial resolution and mean error, of reconstructed images from ptychography is similar (though slightly better) to what one can obtain from near-field holography at identical uence on the specimen. These results support the concept that, if the experiment and image reconstruction are done properly, the sample can be near, or far;wherever you are, photon uence on the specimen sets one limit to spatial resolution. Copyright © 2019, The Authors. All rights reserved.

关键词： Image resolution