通过简并米氏共振的亚波长包封增强单色多极发射。

Enhancing monochromatic multipole emission by a subwavelength enclosure of degenerate Mie resonances.

作者信息

Zhao Jiajun, Zhang Likun, Wu Ying

机构信息

King Abdullah University of Science and Technology (KAUST), Division of Computer, Electrical and Mathematical Science and Engineering, Thuwal, 23955-6900, Saudi Arabia.

National Center for Physical Acoustics and Department of Physics and Astronomy, University of Mississippi, University, Mississippi 38677, USA

出版信息

J Acoust Soc Am. 2017 Jul;142(1):EL24. doi: 10.1121/1.4990010.

DOI:10.1121/1.4990010

PMID:28764465

Abstract

Sound emission is inefficient at low frequencies as limited by source size. This letter presents enhancing emission of monochromatic monopole and multipole sources by enclosing the source with a subwavelength circular enclosure filled of an anisotropic material of a low radial sound speed. The anisotropy is associated with an infinite tangential density along the azimuth. Numerical simulations show that emission gain is produced at frequencies surrounding degenerate Mie resonant frequencies of the enclosure, and meanwhile the radiation directivity pattern is well preserved. The degeneracy is theoretically analyzed. A realization of the material is suggested by using a space-coiling structure.

摘要

由于源尺寸的限制，低频下的声发射效率较低。本文提出通过用充满低径向声速各向异性材料的亚波长圆形外壳包围声源，来增强单色单极子和多极子声源的发射。这种各向异性与沿方位角的无限切向密度相关。数值模拟表明，在外壳简并米氏共振频率附近的频率处产生发射增益，同时辐射方向图得到很好的保留。对这种简并进行了理论分析。建议通过使用空间螺旋结构来实现这种材料。