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- [1] Polariton lasing in InGaN quantum wells at room temperatureOPTO-ELECTRONIC ADVANCES, 2019, 2 (12) : 1 - 5Wu, Jinzhao论文数: 0 引用数: 0 h-index: 0机构: Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R China Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R ChinaLong, Hao论文数: 0 引用数: 0 h-index: 0机构: Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R China Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R ChinaShi, Xiaoling论文数: 0 引用数: 0 h-index: 0机构: Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R China Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R ChinaLuo, Song论文数: 0 引用数: 0 h-index: 0机构: Fudan Univ, Dept Phys, Surface Phys Lab, Shanghai 200433, Peoples R China Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R ChinaChen, Zhanghai论文数: 0 引用数: 0 h-index: 0机构: Fudan Univ, Dept Phys, Surface Phys Lab, Shanghai 200433, Peoples R China Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R ChinaFeng, Zhechuan论文数: 0 引用数: 0 h-index: 0机构: Guangxi Univ, Sch Phys Sci & Technol, Nanning 530004, Peoples R China Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R ChinaYing, Leiying论文数: 0 引用数: 0 h-index: 0机构: Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R China Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R ChinaZheng, Zhiwei论文数: 0 引用数: 0 h-index: 0机构: Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R China Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R ChinaZhang, Baoping论文数: 0 引用数: 0 h-index: 0机构: Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R China Xiamen Univ, Sch Elect Sci & Engn, Dept Elect Engn, Natl Model Microelect Coll, Xiamen 361005, Peoples R China
- [2] Room temperature polariton lasing in quantum heterostructure nanocavitiesSCIENCE ADVANCES, 2019, 5 (04)Kang, Jang-Won论文数: 0 引用数: 0 h-index: 0机构: DGIST, Dept Emerging Mat Sci, Daegu 42988, Daegu 42988, South Korea DGIST, Dept Emerging Mat Sci, Daegu 42988, Daegu 42988, South KoreaSong, Bokyung论文数: 0 引用数: 0 h-index: 0机构: DGIST, Dept Emerging Mat Sci, Daegu 42988, Daegu 42988, South Korea DGIST, Dept Emerging Mat Sci, Daegu 42988, Daegu 42988, South KoreaLiu, Wenjing论文数: 0 引用数: 0 h-index: 0机构: Univ Penn, Dept Mat Sci & Engn, Philadelphia, PA 19104 USA DGIST, Dept Emerging Mat Sci, Daegu 42988, Daegu 42988, South KoreaPark, Seong-Ju论文数: 0 引用数: 0 h-index: 0机构: Gwangju Inst Sci & Technol, Sch Mat Sci & Engn, Gwangju 61005, South Korea DGIST, Dept Emerging Mat Sci, Daegu 42988, Daegu 42988, South KoreaAgarwal, Ritesh论文数: 0 引用数: 0 h-index: 0机构: Univ Penn, Dept Mat Sci & Engn, Philadelphia, PA 19104 USA DGIST, Dept Emerging Mat Sci, Daegu 42988, Daegu 42988, South KoreaCho, Chang-Hee论文数: 0 引用数: 0 h-index: 0机构: DGIST, Dept Emerging Mat Sci, Daegu 42988, Daegu 42988, South Korea DGIST, Dept Emerging Mat Sci, Daegu 42988, Daegu 42988, South Korea
- [3] Polariton Lasing at Room Temperature2013 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), 2013,Grandjean, Nicolas论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Condensed Matter Phys, CH-1015 Lausanne, Switzerland Ecole Polytech Fed Lausanne, Inst Condensed Matter Phys, CH-1015 Lausanne, Switzerland
- [4] Room temperature strong coupling in a semiconductor microcavity with embedded AlGaAs quantum wells designed for polariton lasingOPTICS EXPRESS, 2017, 25 (20): : 24816 - 24826Suchomel, H.论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, Germany Univ Wurzburg, Wilhelm Conrad Rontgen Res Ctr Complex Mat Syst, D-97074 Wurzburg, Germany Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, GermanyKreutzer, S.论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, Germany Univ Wurzburg, Wilhelm Conrad Rontgen Res Ctr Complex Mat Syst, D-97074 Wurzburg, Germany Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, GermanyJoerg, M.论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, Germany Univ Wurzburg, Wilhelm Conrad Rontgen Res Ctr Complex Mat Syst, D-97074 Wurzburg, Germany Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, GermanyBrodbeck, S.论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, Germany Univ Wurzburg, Wilhelm Conrad Rontgen Res Ctr Complex Mat Syst, D-97074 Wurzburg, Germany Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, GermanyPieczarka, M.论文数: 0 引用数: 0 h-index: 0机构: Wroclaw Univ Technol, Lab Opt Spect Nanostruct, Dept Expt Phys, Fac Fundamental Problems Technol, Wybrzeze Wyspianskiego 27, PL-50370 Wroclaw, Poland Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, GermanyBetzold, S.论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, Germany Univ Wurzburg, Wilhelm Conrad Rontgen Res Ctr Complex Mat Syst, D-97074 Wurzburg, Germany Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, GermanyDietrich, C. P.论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, Germany Univ Wurzburg, Wilhelm Conrad Rontgen Res Ctr Complex Mat Syst, D-97074 Wurzburg, Germany Univ St Andrews, Sch Phys & Astron, SUPA, St Andrews KY16 9SS, Fife, Scotland Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, GermanySek, G.论文数: 0 引用数: 0 h-index: 0机构: Wroclaw Univ Technol, Lab Opt Spect Nanostruct, Dept Expt Phys, Fac Fundamental Problems Technol, Wybrzeze Wyspianskiego 27, PL-50370 Wroclaw, Poland Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, GermanySchneider, C.论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, Germany Univ Wurzburg, Wilhelm Conrad Rontgen Res Ctr Complex Mat Syst, D-97074 Wurzburg, Germany Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, GermanyHoefling, S.论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, Germany Univ Wurzburg, Wilhelm Conrad Rontgen Res Ctr Complex Mat Syst, D-97074 Wurzburg, Germany Univ St Andrews, Sch Phys & Astron, SUPA, St Andrews KY16 9SS, Fife, Scotland Univ Wurzburg, Tech Phys, Phys Inst, D-97074 Wurzburg, Germany
- [5] Blue lasing at room temperature in high quality factor GaN/AlInN microdisks with InGaN quantum wellsAPPLIED PHYSICS LETTERS, 2007, 90 (06)Simeonov, D.论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, SwitzerlandFeltin, E.论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, SwitzerlandBuehlmann, H.-J.论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, SwitzerlandZhu, T.论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, SwitzerlandCastiglia, A.论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, SwitzerlandMosca, M.论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, SwitzerlandCarlin, J. -F.论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, SwitzerlandButte, R.论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, SwitzerlandGrandjean, N.论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland
- [6] Room temperature exciton-polariton resonant reflection and suppressed absorption in periodic systems of InGaN quantum wellsJOURNAL OF APPLIED PHYSICS, 2017, 121 (13)Bolshakov, A. S.论文数: 0 引用数: 0 h-index: 0机构: Ioffe Inst, St Petersburg 194021, Russia Ioffe Inst, St Petersburg 194021, RussiaChaldyshev, V. V.论文数: 0 引用数: 0 h-index: 0机构: Ioffe Inst, St Petersburg 194021, Russia Ioffe Inst, St Petersburg 194021, RussiaZavarin, E. E.论文数: 0 引用数: 0 h-index: 0机构: Ioffe Inst, St Petersburg 194021, Russia Ioffe Inst, St Petersburg 194021, RussiaSakharov, A. V.论文数: 0 引用数: 0 h-index: 0机构: Ioffe Inst, St Petersburg 194021, Russia Ioffe Inst, St Petersburg 194021, RussiaLundin, W. V.论文数: 0 引用数: 0 h-index: 0机构: Ioffe Inst, St Petersburg 194021, Russia St Petersburg Natl Res Univ Informat Technol Mech, St Petersburg 197101, Russia Ioffe Inst, St Petersburg 194021, RussiaTsatsulnikov, A. F.论文数: 0 引用数: 0 h-index: 0机构: Ioffe Inst, St Petersburg 194021, Russia St Petersburg Natl Res Univ Informat Technol Mech, St Petersburg 197101, Russia RAS, Submicron Heterostruct Microelect Res & Engn Ctr, St Petersburg 194021, Russia Ioffe Inst, St Petersburg 194021, RussiaYagovkina, M. A.论文数: 0 引用数: 0 h-index: 0机构: Ioffe Inst, St Petersburg 194021, Russia Ioffe Inst, St Petersburg 194021, Russia
- [7] Room temperature polariton lasing in a GaN/AlGaN multiple quantum well microcavityAPPLIED PHYSICS LETTERS, 2008, 93 (05)Christmann, Gabriel论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, SwitzerlandButte, Raphael论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, SwitzerlandFeltin, Eric论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, SwitzerlandCarlin, Jean-Francois论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, SwitzerlandGrandjean, Nicolas论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland Ecole Polytech Fed Lausanne, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland
- [8] Large Rabi splitting in InGaN quantum wells microcavity at room temperatureMATERIALS RESEARCH EXPRESS, 2019, 6 (07):Wu, JinZhao论文数: 0 引用数: 0 h-index: 0机构: Xiamen Univ, Dept Elect Engn, Optoelect Engn Res Ctr, Sch Elect Sci & Engn,Natl Model Microelect Coll, Xiamen 361005, Peoples R China Xiamen Univ, Dept Elect Engn, Optoelect Engn Res Ctr, Sch Elect Sci & Engn,Natl Model Microelect Coll, Xiamen 361005, Peoples R ChinaShi, XiaoLing论文数: 0 引用数: 0 h-index: 0机构: Xiamen Univ, Dept Elect Engn, Optoelect Engn Res Ctr, Sch Elect Sci & Engn,Natl Model Microelect Coll, Xiamen 361005, Peoples R China Xiamen Univ, Dept Elect Engn, Optoelect Engn Res Ctr, Sch Elect Sci & Engn,Natl Model Microelect Coll, Xiamen 361005, Peoples R ChinaLong, Hao论文数: 0 引用数: 0 h-index: 0机构: Xiamen Univ, Dept Elect Engn, Optoelect Engn Res Ctr, Sch Elect Sci & Engn,Natl Model Microelect Coll, Xiamen 361005, Peoples R China Xiamen Univ, Dept Elect Engn, Optoelect Engn Res Ctr, Sch Elect Sci & Engn,Natl Model Microelect Coll, Xiamen 361005, Peoples R ChinaChen, Lan论文数: 0 引用数: 0 h-index: 0机构: Xiamen Univ, Dept Elect Engn, Optoelect Engn Res Ctr, Sch Elect Sci & Engn,Natl Model Microelect Coll, Xiamen 361005, Peoples R China Xiamen Univ, Dept Elect Engn, Optoelect Engn Res Ctr, Sch Elect Sci & Engn,Natl Model Microelect Coll, Xiamen 361005, Peoples R ChinaYing, LeiYing论文数: 0 引用数: 0 h-index: 0机构: Xiamen Univ, Dept Elect Engn, Optoelect Engn Res Ctr, Sch Elect Sci & Engn,Natl Model Microelect Coll, Xiamen 361005, Peoples R China Xiamen Univ, Dept Elect Engn, Optoelect Engn Res Ctr, Sch Elect Sci & Engn,Natl Model Microelect Coll, Xiamen 361005, Peoples R ChinaZheng, ZhiWei论文数: 0 引用数: 0 h-index: 0机构: Xiamen Univ, Dept Elect Engn, Optoelect Engn Res Ctr, Sch Elect Sci & Engn,Natl Model Microelect Coll, Xiamen 361005, Peoples R China Xiamen Univ, Dept Elect Engn, Optoelect Engn Res Ctr, Sch Elect Sci & Engn,Natl Model Microelect Coll, Xiamen 361005, Peoples R ChinaZhang, BaoPing论文数: 0 引用数: 0 h-index: 0机构: Xiamen Univ, Dept Elect Engn, Optoelect Engn Res Ctr, Sch Elect Sci & Engn,Natl Model Microelect Coll, Xiamen 361005, Peoples R China Xiamen Univ, Dept Elect Engn, Optoelect Engn Res Ctr, Sch Elect Sci & Engn,Natl Model Microelect Coll, Xiamen 361005, Peoples R China
- [9] Polariton lasing in AlGaN microring with GaN/AlGaN quantum wellsAPL PHOTONICS, 2023, 8 (02)Delphan, Anthonin论文数: 0 引用数: 0 h-index: 0机构: Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, England Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, EnglandMakhonin, Maxim N.论文数: 0 引用数: 0 h-index: 0机构: Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, England Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, EnglandIsoniemi, Tommi论文数: 0 引用数: 0 h-index: 0机构: Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, England Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, EnglandWalker, Paul M.论文数: 0 引用数: 0 h-index: 0机构: Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, England Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, EnglandSkolnick, Maurice S.论文数: 0 引用数: 0 h-index: 0机构: Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, England Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, EnglandKrizhanovskii, Dmitry N.论文数: 0 引用数: 0 h-index: 0机构: Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, England Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, EnglandSkryabin, Dmitry V.论文数: 0 引用数: 0 h-index: 0机构: Univ Bath, Dept Phys, Bath BA2 7AY, England Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, EnglandCarlin, Jean-Francois论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne EPFL, Inst Phys, CH-1015 Lausanne, Switzerland Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, EnglandGrandjean, Nicolas论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne EPFL, Inst Phys, CH-1015 Lausanne, Switzerland Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, EnglandButte, Raphael论文数: 0 引用数: 0 h-index: 0机构: Ecole Polytech Fed Lausanne EPFL, Inst Phys, CH-1015 Lausanne, Switzerland Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, England
- [10] Room Temperature Polariton Lasing and BEC in Semiconductor Microcavities2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9, 2008, : 1503 - +Baumberg, J. J.论文数: 0 引用数: 0 h-index: 0机构: Univ Cambridge, Dept Phys, Cambridge CB1 0HE, England Univ Cambridge, Dept Phys, Cambridge CB1 0HE, England论文数: 引用数: h-index:机构:von Hoegersthal, G. Baldassarri Hoeger论文数: 0 引用数: 0 h-index: 0机构: Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England Univ Cambridge, Dept Phys, Cambridge CB1 0HE, EnglandGrundy, A.论文数: 0 引用数: 0 h-index: 0机构: Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England Univ Cambridge, Dept Phys, Cambridge CB1 0HE, EnglandLagoudakis, P. G.论文数: 0 引用数: 0 h-index: 0机构: Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England Univ Cambridge, Dept Phys, Cambridge CB1 0HE, EnglandKavokin, A.论文数: 0 引用数: 0 h-index: 0机构: Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England Univ Cambridge, Dept Phys, Cambridge CB1 0HE, EnglandChristmann, G.论文数: 0 引用数: 0 h-index: 0机构: EPLF, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland Univ Cambridge, Dept Phys, Cambridge CB1 0HE, EnglandButte, R.论文数: 0 引用数: 0 h-index: 0机构: EPLF, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland Univ Cambridge, Dept Phys, Cambridge CB1 0HE, EnglandFeltin, E.论文数: 0 引用数: 0 h-index: 0机构: EPLF, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland Univ Cambridge, Dept Phys, Cambridge CB1 0HE, EnglandCarlin, J. -F.论文数: 0 引用数: 0 h-index: 0机构: EPLF, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland Univ Cambridge, Dept Phys, Cambridge CB1 0HE, EnglandGrandjean, N.论文数: 0 引用数: 0 h-index: 0机构: EPLF, Inst Quantum Elect & Photon, CH-1015 Lausanne, Switzerland Univ Cambridge, Dept Phys, Cambridge CB1 0HE, EnglandSolnyshkov, Dmitry论文数: 0 引用数: 0 h-index: 0机构: Univ Blaise Pascal, LASMEA, UMR 6602, CNRS, F-63177 Clermont Ferrand, France Univ Cambridge, Dept Phys, Cambridge CB1 0HE, EnglandMalpuech, G.论文数: 0 引用数: 0 h-index: 0机构: Univ Blaise Pascal, LASMEA, UMR 6602, CNRS, F-63177 Clermont Ferrand, France Univ Cambridge, Dept Phys, Cambridge CB1 0HE, England