题　目： Novel Ways of Sound Field Control with Acoustic Metamaterials
报告人： 马冠聪 （香港浸会大学）
时　间： 05月25日（周五），下午 3:00 - 4:00
地　点： 物理馆502会议室

Abstract:

The research of acoustic metamaterials has matured into a robust and active field driven by scientific discoveries and application potentials. In this talk, I will discuss our recent progress in sound field control with membrane-type acoustic metamaterials. In the first part, I will show the way to reshape reverberating sound field in a room by building a “spatial sound modulator” which is based on a metasurface that is an array of actively controllable metamaterials. We show the functionality of the on-demand creation of quiet zones and acoustic hotspots at audio frequencies anywhere in a reverberating room. This is the first realization of the adaptive wavefield shaping for acoustic waves. In the second part, I will show that by building a subwavelength absorber for spherical waves, the focal spot formed by an isotropic converging wave in 3D can become smaller than the diffraction limit. The idea is based on the observation that diffraction limit is the consequence of the interference between incoming and outgoing waves, therefore by removing a majority of the outgoing energy with a subwavelength absorber, the total field profile is drastically modified, leading to sub-diffraction focusing. This result can also be interpreted as the realization of a stand-alone anti-causal Green’s function up to the surface of the absorber. The absorber also plays an important role of an acoustic sink, which is the time-reversal counterpart of a source.

Bio：

马冠聪博士，现于香港浸会大学物理系任职助理教授。2007年本科毕业于华南理工大学。2007至2012年就读于香港科技大学物理学系，取得物理学博士学位。博士期间主要从事声波超材料的研究。2012-2017年分别在香港科技大学物理系和高等研究院任博士后研究员。2018年起在香港浸会大学物理系担任助理教授。研究兴趣包括声波超材料，声子晶体，声拓扑，非厄米系统等相关的经典波现象。相继在国际著名期刊 Nature Materials, Nature Physics, Nature Communications, Physical Review X, Physical Review Letters 等发表文章 15 篇，并在 Science Advances 发表关于声波超材料的综述文章。在国际著名会议 META，PIERS 等做邀请报告 6 次，并两次担任 META 会议(2017年韩国仁川，2018年法国马赛)的声波超材料和声子晶体分会场的组织者和会场主席。