title: Manipulating acoustic wavefront by inhomogeneous impedance and steerable extraordinary reflection.
abstract: We unveil the connection between the acoustic impedance along a flat surface and the reflected acoustic wavefront, in order to empower a wide wariety of novel applications in acoustic community. Our designed flat surface can generate double reflections: the ordinary reflection and the extraordinary one whose wavefront is manipulated by the proposed impedance-governed generalized Snell's law of reflection (IGSL). IGSL is based on Green's function and integral equation, instead of Fermat's principle for optical wavefront manipulation. Remarkably, via the adjustment of the designed specific acoustic impedance, extraordinary reflection can be steered for unprecedented acoustic wavefront while that ordinary reflection can be surprisingly switched on or off. The realization of the complex discontinuity of the impedance surface has been proposed using Helmholtz resonators.
authors.affiliation: 1] Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Republic of Singapore [2] Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117546, Republic of Singapore and.
authors.forename: Jiajun
authors.initials: J
authors.lastname: Zhao
authors.forename: Baowen
authors.initials: B
authors.lastname: Li
authors.forename: Zhining
authors.initials: Z
authors.lastname: Chen
authors.forename: Cheng-Wei
authors.initials: CW
authors.lastname: Qiu