Unidirectional Negative Refraction at an Exceptional Point of Acoustic P T-Symmetric Systems  

作　　者：刘宸 蓝君 顾仲明 祝捷 Chen Liu;Jun Lan;Zhongming Gu;Jie Zhu(Institute of Acoustics,School of Physics Science and Engineering,Tongji University,Shanghai 200092,China;State Key Laboratory of Acoustics,Chinese Academy of Sciences,Beijing 100190,China;College of Computer Science and Technology,Nanjing Tech University,Nanjing 211800,China)

机构地区：[1]Institute of Acoustics,School of Physics Science and Engineering,Tongji University,Shanghai 200092,China [2]State Key Laboratory of Acoustics,Chinese Academy of Sciences,Beijing 100190,China [3]College of Computer Science and Technology,Nanjing Tech University,Nanjing 211800,China

出　　处：《Chinese Physics Letters》2023年第12期56-61,共6页中国物理快报（英文版）

基　　金：supported by the National Key R&D Program of China (Grant Nos. 2022YFA1404400 and 2022YFA1404403);the National Natural Science Foundation of China (Grant No. 92263208);the Natural Science Foundation of Jiangsu Province (Grant No. BK20210541);the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (Grant No. 21KJB140003);the Fundamental Research Funds for the Central Universities;the Open Fund of State Key Laboratory of Acoustics (Grant No. SKLA202313)。

摘　　要：We demonstrate a method to realize unidirectional negative refraction in an acoustic parity-time(P T)-symmetric system, which is composed of a pair of metasurfaces sandwiching an air gap. The pair of metasurfaces possesses loss and gain modulations. The unidirectional negative refraction, which is strictly limited to the case of incident wave imposing on the loss end of the metasurface, is demonstrated at the exception point(EP) in this P T-symmetric system, while the incidence from the other side leads to strong reflection. Based on rigorous calculations, we explicitly show the underlying mechanism of this model to achieve unidirectional wave scatterings around the EP in the parametric space. In addition, the perfect imaging of a point source in the three-dimensional space, as a signature of negative refraction, is simulated to provide a verification of our work. We envision that this work may sharpen the understanding of P T-symmetric structures and inspire more acoustic functional devices.

关 键 词：REFRACTION UNIDIRECTIONAL SYMMETRIC 

分 类 号：O42[理学—声学]