Natural exceptional points in the excitation spectrum of a light-matter system
Andrzej Opala, Magdalena Furman, Mateusz Król, Rafał Mirek, Krzysztof Tyszka, Bartłomiej Seredyński, Wojciech Pacuski, Jacek Szczytko, Michał Matuszewski, Barbara Piętka
我们通过光学方式调控光-物质相互作用，在激子-极化激元系统的激发谱中观测到自然例外点。所观测到的例外点不需要任何空间或偏振自由度，而完全源于从弱光-物质耦合到强光-物质耦合的转变。我们证明这些例外点并不与光子激光阈值重合，从而证实了先前的理论预测[Phys. Rev. Lett. 122, 185301 (2019), Optica 7, 1015 (2020)]。利用一种由强相干激光泵浦诱导上转换激发的技术，我们在耦合强度和粒子动量的参数空间中环绕了该例外点。我们这种局域光学调控光-物质耦合的方法，为研究耗散相变和非厄米拓扑态等基本现象铺平了道路。
英文摘要：
We observe natural exceptional points in the excitation spectrum of an exciton-polariton system by optically tuning the light-matter interactions. The observed exceptional points do not require any spatial or polarization degrees of freedom and result solely from the transition from weak to strong light-matter coupling. We demonstrate that they do not coincide with the threshold for photon lasing, confirming previous theoretical predictions [Phys. Rev. Lett. 122, 185301 (2019), Optica 7, 1015 (2020) ]. Using a technique where a strong coherent laser pump induces up-converted excitations, we encircle the exceptional point in the parameter space of coupling strength and particle momentum. Our method of local optical control of light-matter coupling paves the way to investigation of fundamental phenomena including dissipative phase transitions and non-Hermitian topological states.
Coherent Perfect Tunneling at Exceptional Points via Directional Degeneracy
Institute of Estuarine and Coastal Research, School of Ocean Engineering and Technology, Sun Yat-Sen University / Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai)（中山大学海洋工程与技术学院河口海岸研究所/南方海洋科学与工程广东省实验室（珠海））；State and Local Joint Engineering Laboratory of Estuarine Hydraulic Technology / Guangdong Provincial Engineering Research Center of Coasts, Islands and Reefs / Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering / Guangdong Provincial Key Laboratory of Information Technology for Deep Water Acoustics / Key Laboratory of Comprehensive Observation of Polar Environment (Sun Yat-Sen University), Ministry of Education（河口水动力技术省部共建国家重点实验室培育基地/广东省海岸岛礁工程研究中心/广东省海洋资源与海岸工程重点实验室/广东省深水声学信息技术重点实验室/教育部极地环境综合观测重点实验室（中山大学））；Zhuhai Research Center, Hanjiang National Laboratory（汉江国家实验室珠海研究中心）；School of Marine Sciences, Sun Yat-Sen University（中山大学海洋科学学院）
Enantiosensitive exceptional points in open chiral systems
Max-Born-Institut（马克斯·玻恩研究所）；Attosecond Quantum Physics Laboratory, Physics Department, King’s College London（伦敦国王学院物理学院阿秒量子物理实验室）；Technion-Israel Institute of Technology（以色列理工学院）；Institute of Advanced Studies in Theoretical Chemistry, Technion-Israel Institute of Technology（以色列理工学院理论化学高级研究所）；Department of Physics, Humboldt Universität zu Berlin（柏林洪堡大学物理系）；Department of Physics, Imperial College London（伦敦帝国理工学院物理系）；Technische Universität Berlin（柏林工业大学）
