摘要
In recent years, peculiar physical phenomena enabled by non-Hermitian systems, especially the parity-time(PT)-symmetric systems, have drawn tremendous research interests. Particularly, special spectral degeneracies known as exceptional points(EPs) and coherent perfect absorber-laser(CPAL) points where zero and infinite large eigenvalues coexist are the most popular topics to be studied. To date, the discussions of EPs that serve as transition boundaries between broken PT-symmetry phase and exact PT-symmetry phase have been intensively presented. However, the theoretical analysis and experimental validations of CPAL points are inadequate. Different from EPs, CPAL points, as a special solution of broken PT-symmetry phase, may exhibit even further counterintuitive physical features, which may have significant implications to study non-Hermitian physics. Here, we review some recent advances of CPAL phenomena in different sub-disciplines of physics, including optics, electronics and electromagnetics, and acoustics.Additionally, we also provide an envision of future directions and applications of CPAL systems.
近年来,非厄米系统,特别是宇称-时间(PT)对称系统引起的特殊物理现象吸引了许多科研人员。具有光谱退化性质的异常点(EP)和特征值分别为无限大及零的相干完美吸收-激光(CPAL)点是其中最为热门的研究课题。迄今为止,对于作为PT对称系统的破缺相和确定相边界的EP讨论已经有了非常多的成果。然而,针对CPAL点的理论分析和实验验证,相对于EP来说,仍有不足。与EP不同,CPAL点作为PT对称系统中破缺相中的一个特殊解,可能会表现出更加违反直觉的物理特征,而这些表现可能对研究非厄米物理学有着重要的意义。本文回顾了在不同物理子学科中关于CPAL现象的一些研究,包括光学、电子和电磁学、以及声学。此外,对于CPAL系统未来可能的发展方向及应用给出了一些设想。
