Asymmetric acoustic retroflection with a non-Hermitian metasurface mirror. (11th November 2021)

• Record Type: Journal Article
• Authors: Ju, Fangfang; Zou, Xiao; Qian, Sheng-You; Liu, Xiaojun
• Is Part Of: Applied physics express. Volume 14:Number 12(2021)
• Publication Date: 2021-11-11
• Subjects: Acoustic metasurfaces -- Asymmetric acoustic retroflection -- non-Hermitian metasurfaces; Physics -- Periodicals; Technology -- Periodicals; 621.05
• DOI: 10.35848/1882-0786/ac3543
• Languages: English
• ISSNs: 1882-0778

Abstract

Abstract: We proposed and designed a non-Hermitian metasurface mirror consisting of two-layers acoustic labyrinthine metamaterials with a full phase control and inherent loss. It yields strongly asymmetric acoustic retroflection (>35 dB) for two opposite incident angles: free retroflection for positive incidence (PI) and strong absorption for negative incidence (NI). It is due to the different diffraction orders related to the period grating for two opposite incident angles: the value of 0 (without multiple reflections) for PI and the value of 2 (with multiple reflections) for NI. Our design may have prospective applications in acoustic sensing, acoustic antennas and noise control.