2018/06/20 by Xu-Lin Zhang, Tianshu Jiang, Hong-Bo Sun +1 · 1 citation
Physics and Astronomy · #physics.optics #physics.class-ph
paper · pdf · doi:10.1038/s41377-019-0200-8
published as Light: Science & Applications volume 8, Article number: 88 (2019) · 8 pages, 5 figures
arxiv created 2018/06/20 · arxiv updated 2019/10/16
Dynamically encircling an exceptional point (EP) in parity-time (PT) symmetric systems shows an interesting chiral dynamics, leading to asymmetric mode switching in which the output modes are different when the encircling direction is reversed. Here we show that the dynamical encircling of an EP in anti-PT-symmetric systems can also result in chiral dynamics if the starting/end point lies in the PT-broken phase, in contrast to PT-symmetric systems where chiral dynamics emerges if the starting/end point lies in the PT-unbroken phase. For many applications, such as signal processing using waveguides, the asymmetric mode switching of symmetry-broken modes in anti-PT-symmetric systems is more useful since each eigenmode is localized in one waveguide only. We develop an analytic theory for anti-PT-symmetric chiral dynamics and perform experiments using three waveguides to demonstrate the asymmetric mode switching. The new wave-manipulation phenomena observable in anti-PT-symmetric systems may pave the way towards designing on-chip optical systems with novel functionalities.