Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Acoustic Wavefront Manipulation: Impedance Inhomogeneity and
  Extraordinary Reflection   Optical wavefront can be manipulated by interfering elementary beams with
phase inhomogeneity. Therefore a surface allowing huge, abrupt and
position-variant phase change would enable all possibilities of wavefront
engineering. However, one may not have the luxury of efficient
abrupt-phase-changing materials in acoustics. This motivates us to establish a
counterpart mechanism for acoustics, in order to empower the wide spectrum of
novel acoustic applications. Remarkably, the proposed impedance-governed
generalized Snell's law (IGSL) of reflection is distinguished from that in
optics. Via the manipulation of inhomogeneous acoustic impedance, extraordinary
reflection can be tailored for unprecedented wavefront manipulation while
ordinary reflection can be surprisingly switched on or off. Our results may
power the acoustic-wave manipulation and engineering. We demonstrate novel
acoustic applications by planar surfaces designed with IGSL.

21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex