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Journal of Applied Physics 2018年第7期123卷

作者： Guiying Xu Pan Ren Tie Lin Xiaofeng Wu Yanhua Zhang Sitong Niu Trevor P. Bailey 1Beijing Municipal Key Lab of Advanced Energy Materials and Technology School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China 2National Laboratory for Infrared Physics Shanghai Institute of Technical Physics of the Chinese Academy of Science Shanghai 200083 China 3Department of Physics University of Michigan Ann Arbor Michigan 48109 USA

Recently, we realized that several small mistakes were produced during the modification of formula expressions presented in Tables I and II.1 We are certain tha

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Mid-infrared variability of changing-look agns

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arXiv 2017年

作者： Sheng, Zhenfeng Wang, Tinggui Jiang, Ning Yang, Chenwei Yan, Lin Dou, Liming Peng, Bo CAS Key Laboratory for Researches in Galaxies and Cosmology University of Sciences and Technology of China Hefei Anhui230026 China School of Astronomy and Space Science University of Science and Technology of China Hefei230026 China Caltech Optical Observatories Cahill Center for Astronomy and Astrophysics California Institute of Technology PasadenaCA91125 United States Infrared Processing and Analysis Center California Institute of Technology PasadenaCA91125 United States Center for Astrophysics Guangzhou University Guangzhou510006 China Astronomy Science and Technology Research Laboratory Department of Education of Guangdong Province Guangzhou510006 China

It is known that some active galactic nuclei (AGNs) transit from Type 1 to Type 2 or vice versa. There are two explanations for the so-called changing-look AGNs: one is the dramatic change of the obscuration along the line of sight, and the other is the variation of accretion rate. In this Letter, we report the detection of large amplitude variations in the mid-infrared luminosity during the transitions in 10 changing-look AGNs using Wide-field infrared Survey Explorer (WISE) and newly released Near-Earth Object WISE Reactivation data. The mid-infrared light curves of 10 objects echo the variability in the optical band with a time lag expected for dust reprocessing. The large variability amplitude is inconsistent with the scenario of varying obscuration, rather it supports the scheme of dramatic change in the accretion rate. Copyright © 2017, The Authors. All rights reserved.

关键词： infrared devices

The blanco DECam bulge survey. I. The survey description and early results

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arXiv 2020年

作者： Rich, R. Michael Johnson, Christian I. Young, Michael Simion, Iulia T. Clarkson, William I. Pilachowski, Catherine Michael, Scott Kunder, Andrea Vivas, A. Katherina Koch, Andreas Marchetti, Tommaso Ibata, Rodrigo Martin, Nicolas Robin, Annie C. Lagarde, Nadége Collins, Michelle Ivezić, Željko de Propris, Roberto Shen, Juntai Gerhard, Ortwin Soto, Mario Department of Physics & Astronomy Univ. of California Los Angeles PAB 430 Portola Plaza Los AngelesCA90095-1547 United States Space Telescope Science Institute 3700 San Martin Drive BaltimoreMD21218 United States Indiana University University Information Technology Services CIB 2709 E. 10th Street BloomingtonIN47401 United States Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory 80 Nandan Road Shanghai20030 China Department of Natural Sciences University of Michigan-Dearborn 4901 Evergree Rd DearbornMI48128 United States Indiana University Department of Astronomy SW319 727 E 3rd Street BloomingtonIN47405 United States College of Arts & Sciences St Martin’s University Ernsdorff Center 130 5000 Abbey Way SE LaceyWA98503 United States Cerro Tololo Inter-American Observatory NSF’s National Optical-Infrared Astronomy Research Laboratory Casilla 603 La Serena Chile Zentrum für Astronomie der Universität Heidelberg Astronomisches Rechen-Institut Heidelberg69120 Germany European Southern Observatory Karl Schwarzschild-Strasse 2 Garching bei Munchen85748 Germany Observatoire de Strasbourg 11 rue de l’observatoire Strasbourg67000 France Institut Utinam CNRS UMR 6213 Univ. Bourgogne Franche-Comté OSU THETA Observatoire de Besancon BP 1615 Besancon Cedex25010 France Department of Physics Univ. of Surrey SurreyGU2 7XH United Kingdom University of Washington Astronomy Dept Box 351560 3910 15th Av. NE SeattleWA98195-1580 United States Finnish Center for Astronomy with ESO Turku University Vesilinnantie 5 Turku Finland Department of Astronomy School of Physics and Astronomy Shanghai Jiao Tong University 800 Dongchuan Road Shanghai200240 China

The Blanco Dark Energy Camera (DECam) Bulge survey is a Vera Rubin Observatory (LSST) pathfinder imaging survey, spanning ∼ 200 sq. deg. of the Southern Galactic bulge, −2◦ ◦ and −11◦ ◦. We have employed the CTIO-4m telescope and the Dark Energy Camera (DECam) to image a contiguous ∼ 200 sq. deg. region of the relatively less reddened Southern Galactic bulge, in SDSS u + Pan-STARRSgrizy. Optical photometry with its large colour baseline will be used to investigate the age and metallicity distributions of the major structures of the bulge. Included in the survey footprint are 26 globular clusters imaged in all passbands. Over much of the bulge, we have Gaia DR2 matching astrometry to i ∼ 18, deep enough to reach the faint end of the red clump. This paper provides the background, scientific case, and description of the survey. We present an array of new reddening-corrected colour-magnitude diagrams that span the extent of Southern Galactic bulge. We argue that a population of massive stars in the blue loop evolutionary phase, proposed to lie in the bulge, are instead at ∼ 2 kpc from the Sun and likely red clump giants in the old disk. A bright red clump near (l, b) = (+8◦, −4◦) may be a feature in the foreground disk, or related to the long bar reported in earlier work. We also report the first map of the blue horizontal branch population spanning the BDBS field of regard, and our data does not confirm the reality of a number of proposed globular clusters in the bulge. Copyright © 2020, The Authors. All rights reserved.

关键词： Surveys

(INVITED) Methods for determining the refractive indices and thermo-optic coefficients of chalcogenide glasses at MIR wavelengths

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Optical Materials: X 2019年 2卷

作者： Y. Fang D. Furniss D. Jayasuriya H. Parnell Z.Q. Tang D. Gibson S. Bayya J. Sanghera A.B. Seddon T.M. Benson Mid-Infrared Photonics Group George Green Institute for Electromagnetics Research Faculty of Engineering University of Nottingham University Park NG7 2RD Nottingham UK Now Shenzhen Engineering Laboratory of Phosphorene and Optoelectronics Collaborative Innovation Center for Optoelectronic Science and Technology And Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province Shenzhen University Shenzhen 518060 People's Republic of China Now at ThorLabs 1 St. Thomas Place Ely CB7 4EX UK Now at Granta Design Ltd. (Materials Intelligence) Rustat House 62 Clifton Rd Cambridge CB1 7EG UK Naval Research Laboratory Washington DC 20375 USA

Chalcogenide glasses have attracted much attention for the realization of photonic components owing to their outstanding optical properties in the mid-infrared (MIR) region. However, relatively few refractive index dispersion data are presently available for these glasses at MIR wavelengths. This paper presents a mini review of methods we have both used and developed to determine the refractive indices and thermo-optic coefficients of chalcogenide glasses at MIR wavelengths, and is supported by new results. The mini review should be useful to both new and established researchers in the chalcogenide glass field and fields of MIR optics, fiber-optics and waveguides. Three groups of methods are distinguished: (1) spectroscopic ellipsometry, (2) prism-based methods, and (3) methods using Fourier transform infrared (FTIR) transmission data. The mini review is supported by a brief discussion of refractive index models.

关键词： Refractive index dispersion Thermo-optic coefficient Chalcogenide glass

Oriented Graphene Nanoribbons Embedded in Hexagonal Boron Nitride Trenches

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arXiv 2017年

作者： Chen, Lingxiu He, Li Wang, Hui Shan Wang, Haomin Tang, Shujie Cong, Chunxiao Xie, Hong Li, Lei Xia, Hui Li, Tianxin Wu, Tianru Zhang, Daoli Deng, Lianwen Yu, Ting Xie, Xiaoming Jiang, Mianheng State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences 865 Changning Road Shanghai200050 China School of Physical Science and Technology ShanghaiTech University 319 Yueyang Road Shanghai200031 China School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan430074 China School of Physics and Electronics Central South University Changsha410083 China Graduate University of the Chinese Academy of Sciences Beijing100049 China Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link Singapore637371 Singapore State Key Laboratory of ASIC & System School of Information Science and Technology Fudan University Shanghai200433 China National Laboratory for Infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences 500 Yu Tian Road Shanghai200083 China

Graphene nanoribbons (GNRs) are ultra-narrow strips of graphene that have the potential to be used in high-performance graphene-based semiconductor electronics. However, controlled growth of GNRs on dielectric substrates remains a challenge. Here, we report the successful growth of GNRs directly on hexagonal boron nitride substrates with smooth edges and controllable widths using chemical vapour deposition. The approach is based on a type of template growth that allows for the in-plane epitaxy of mono-layered GNRs in nano-trenches on hexagonal boron nitride with edges following a zigzag direction. The embedded GNR channels show excellent electronic properties, even at room temperature. Such in-plane hetero-integration of GNRs, which is compatible with integrated circuit processing, creates a gapped channel with a width of a few benzene rings, enabling the development of digital integrated circuitry based on GNRs. Copyright © 2017, The Authors. All rights reserved.

关键词： Boron nitride

SILVERRUSH. VIII. Spectroscopic identifications of early large scale structures with Protoclusters over 200 Mpc at z ∼ 6 − 7: Strong associations of dusty star-forming galaxies

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arXiv 2019年

作者： Harikane, Yuichi Ouchi, Masami Ono, Yoshiaki Fujimoto, Seiji Donevski, Darko Shibuya, Takatoshi Faisst, Andreas L. Goto, Tomotsugu Hatsukade, Bunyo Kashikawa, Nobunari Kohno, Kotaro Hashimoto, Takuya Higuchi, Ryo Inoue, Akio K. Lin, Yen-Ting Martin, Crystal L. Overzier, Roderik Smail, Ian Toshikawa, Jun Umehata, Hideki Ao, Yiping Chapman, Scott Clements, David L. Im, Myungshin Jing, Yipeng Kawaguchi, Toshihiro Lee, Chien-Hsiu Lee, Minju M. Lin, Lihwai Matsuoka, Yoshiki Marinello, Murilo Nagao, Tohru Onodera, Masato Toft, Sune Wang, Wei-Hao Institute for Cosmic Ra Research Universit of Tok o 5-1-5 Kashiwanoha Kashiwa Chiba277-8582 Japan Department of Physics Graduate School of Science University of Tokyo 7-3-1 Hongo Bunkyo Tokyo113-0033 Japan National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Universit of Tok o Kashiwa Ja an277-8583 Department of Astronomy Graduate School of Science University of Tokyo 7-3-1 Hongo Bunkyo Tokyo113-0033 Japan Aix Marseille University CNRS LAM Laboratoire dAstrophysique de Marseille Marseille France SISSA via Bonomea 265 Trieste ItalI-34136 Italy Kitami Institute of Technolo 165 Koen-cho Kitami Hokkaido 090-8507 Ja an Japan Infrared Processing and Analysis Center California Institute of Technology MC 100-22 770 South Wilson Ave. PasadenaCA91125 United States Institute of Astronom National Tsin Hua Universit No 101 Section 2 Kuan -Fu Road Hsinchu Taiwan Institute of Astronomy Graduate School of Science University of Tokyo 2-21-1 Osawa Mitaka Tokyo181-0015 Japan Department of Environmental Science and Technology Faculty of Design Technology Osaka Sangyo University 3-1-1 Nagaito Daito Osaka574-8530 Japan Institute of Astronomy & Astrophysics Academia Sinica Taipei 106 Taiwan Department of Physics University of California Santa BarbaraCA93106 United States Observatorio Nacional Rua Jose Cristino 77 Sao Cristovao Rio de Janeiro-RJCEP 20921-400 Brazil Universidade de Sao Paulo Instituto de Astronomia Geofísica e Ciências Atmosféricas Departamento de Astronomia São Paulo SP05508-090 Brazil Centre for Extragalactic Astronomy Department of Physics Durham University South Road DurhamDH1 3LE United Kingdom RIKEN Cluster for Pioneering Research 2-1 Hirosawa Wako-shi Saitama351-0198 Japan Purple Mountain Observatory & Key Laboratory for Radio Astronomy Chinese Academy of Sciences 8 Yuanhua Road Nanjing210034 China Department of Physics and Atmospheric Science Dalhousie University Halifax NSB3H 3J5 Canada As

We have obtained three-dimensional maps of the universe in ∼ 200×200×80 comoving Mpc3 (cMpc3) volumes each at z = 5.7 and 6.6 based on a spectroscopic sample of 179 galaxies that achieves & 80% completeness down to the Lyα luminosity of log(LLyα/[erg s−1]) = 43.0, based on our Keck and Gemini observations and the literature. The maps reveal filamentary large-scale structures and two remarkable overdensities made out of at least 44 and 12 galaxies at z = 5.692 (z57OD) and z = 6.585 (z66OD), respectively, making z66OD the most distant overdensity spectroscopically confirmed to date with > 10 spectroscopically confirmed galaxies. We compare spatial distributions of submillimeter galaxies at z ' 4−6 with our z = 5.7 galaxies forming the large-scale structures, and detect a 99.97% signal of cross correlation, indicative of a clear coincidence of dusty star-forming galaxy and dust unobscured galaxy formation at this early epoch. The galaxies in z57OD and z66OD are actively forming stars with star formation rates (SFRs) & 5 times higher than the main sequence, and particularly the SFR density in z57OD is 10 times higher than the cosmic average at the redshift (a.k.a. the Madau-Lilly plot). Comparisons with numerical simulations suggest that z57OD and z66OD are protoclusters that are progenitors of the present-day clusters with halo masses of ∼ 1014 M. Copyright © 2019, The Authors. All rights reserved.

关键词： Galaxies

Edge Control of Graphene Domains Grown on Hexagonal Boron Nitride

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arXiv 2017年

作者： Chen, Lingxiu Wang, Haomin Tang, Shujie He, Li Wang, Hui Shan Wang, Xiujun Xie, Hong Wu, Tianru Xi, Hui Li, Tianxin Xie, Xiaoming State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai200050 China School of Physical Science and Technology ShanghaiTech University Shanghai200031 China School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan430074 China School of Physics and Electronics Central South University Changsha410083 China National Laboratory for Infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai200083 China CAS Center for Excellence in Superconducting Electronics Chinese Academy of Sciences Shanghai200050 China School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Beijing100049 China

Edge structure of graphene has a significant influence on its electronic properties. However, control over the edge structure of graphene domains on insulating substrates is still challenging. Here we demonstrate edge control of graphene domains on hexagonal boron nitride (h-BN) by modifying ratio of working-gases. Edge directions were determined with the help of both moiré pattern and atomic-resolution image obtained via atomic force microscopy measurement. It is believed that the variation on graphene edges mainly attributes to different growth rates of armchair and zigzag edges. This work demonstrated here points out a potential approach to fabricate graphene ribbons on h-BN. Copyright © 2017, The Authors. All rights reserved.

关键词： Boron nitride

Photodetectors: Ultrasensitive Room‐Temperature Terahertz Direct Detection Based on a Bismuth Selenide Topological Insulator (Adv. Funct. Mater. 31/2018)

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Advanced Functional Materials 2018年第31期28卷

作者： Weiwei Tang Antonio Politano Cheng Guo Wanlong Guo Changlong Liu Lin Wang Xiaoshuang Chen Wei Lu State Key Laboratory of Infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences 500 Yutian Road Shanghai 200083 China Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China Hefei 230026 China University of Chinese Academy of Sciences Beijing 100049 China Fondazione Istituto Italiano di Tecnologia Graphene Labs via Morego 30 16163 Genova Italy

Linear and nonlinear optical properties of Sb-doped GeSe_2 thin films

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Chinese Physics B 2015年第6期24卷 483-487页

作者：张振营陈芬陆顺斌王永辉沈祥戴世勋聂秋华 College of Information Science and Engineering Ningbo University Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education College of Physics and Microelectronic ScienceHunan University Laboratory of Infrared Materials and Devices Advanced Technology Research InstituteNingbo University

Sb-doped GeSe2 chalcogenide thin films are prepared by the magnetron co-sputtering method. The linear optical properties of as-deposited films are derived by analyzing transmission spectra. The refractive index rises and the optical band gap decreases from 2.08 eV to 1.41 eV with increasing the Sb content. X-ray photoelectron spectra further confirm the formation of a covalent Sb--Se bond. The third-order nonlinear optical properties of thin films are investigated under femtosecond laser excitation at 800 nm. The results show that the third-order nonlinear optical properties are enhanced with increasing the concentration of Sb. The nonlinear refraction indices of these thin films are measured to be on the order of 10-18 m2/W with a positive sign and the nonlinear absorption coefficients are obtained to be on the order of 10-10 m/W. These excellent properties indicate that Sb-doped Ge-Se films have a good prospect in the applications of nonlinear optical devices.

关键词： chalcogenides films refractive index optical band gap nonlinear optical properties

Stable single-photon detection based on Si-avalanche photodiode in a large temperature variation range

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Optoelectronics Letters 2015年第5期11卷 321-324页

作者：颜佩琴李召辉师亚帆冯百成杜秉乘杜艳伟潭天乐吴光 State Key Laboratory of Precision Spectroscopy East China Normal University Shanghai Institute of Aerospace Control Technology China Aerospace Science and Technology Corporation Infrared Exploration Technology Research and Development Center

In this paper, we present a stable single-photon detection method based on Si-avalanche photodiode(Si-APD) operating in Geiger mode with a large temperature variation range. By accurate temperature sensing and direct current(DC) bias voltage compensation, the single-photon detector can work stably in Geiger mode from-40 °C to 35 °C with an almost constant avalanche gain. It provides a solution for single-photon detection at outdoor operation in all-weather conditions.

关键词： photodiode photon weather compensation fitting outdoor tempera illumination stabilize amplifier