PT-symmetric acoustics
PT-symmetric acoustics
复制标题
DOI：
10.1121/1.4920752
复制
发表时间：
2015-04
影响因子：
2.4
通讯作者：
Xue‐Feng Zhu;H. Ramézani;Chengzhi Shi;Jie Zhu;Xiang Zhang
中科院分区：
文献类型：
--
作者：
Xue‐Feng Zhu;H. Ramézani;Chengzhi Shi;Jie Zhu;Xiang Zhang
引入了声宇称-时间（PT）对称性的概念，并将其用于研究由损耗和增益单元组成的声PT对称介质中的异常散射行为。声PT对称介质的分析研究表明，这些介质可以被设计成在特定频率下实现单向透明，称为例外点（EP）。在EP处发生的这种单向透明是由于周期性损耗和增益单元的不对称布置，其导致PT对称介质的两侧上的不同布拉格散射。仔细观察两侧的反射相位，可以发现EP一侧的反射相位突然跳跃。这种类似阶梯函数的行为导致反射波在该侧的无限延迟时间，因此介质在该方向上变得无反射。将声学PT对称性的概念与变换声学相结合，设计了一种在大气中不可见的二维声隐身衣。
The concept of acoustic parity-time (PT) symmetry is introduced and used for the study of extraordinary scattering behavior in acoustic PT-symmetric media consist of loss and gain units. The analytical study of acoustic PT-symmetric media shows that these media can be designed to achieve unidirectional transparency at specific frequencies named exceptional points (EPs). This unidirectional transparency occurs at the EPs is due to the asymmetrical arrangement of the periodic loss and gain units that results in different Bragg scatterings on the two sides of the PT-symmetric media. A close look at the phases of the reflections on both sides reveals a sudden jump of the reflection phase on one side at the EPs. This step-function like behavior causes an infinite delay time of the reflected wave on that side, and hence the media become reflectionless in that direction. Combining the concept of acoustic PT-symmetry with transformation acoustics, we design a two-dimensional acoustic cloak that is invisible in a ...