Emulating exceptional-point encirclements using imperfect (leaky) photonic components: asymmetric mode-switching and omni-polarizer action

Non-Hermitian systems have recently attracted significant attention in photonics. One of the hallmarks of these systems is the possibility of realizing asymmetric mode-switching and omni-polarizer action through the dynamic encirclement of exceptional points (EPs). Here, we offer a new perspective on the operating principle of these devices, and we theoretically and experimentally show that linear asymmetric mode-switching and omni-polarizer action can be easily realized-with the same performance and limitations-using simple configurations that emulate the physics involved in encircling EPs without the complexity of actual encirclement schemes. The proposed concept of encirclement emulators and our theoretical and experimental results may allowbetter assessment of the limitations, practical potential, and applications of EP encirclements in non-Hermitian photonics. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

Non-Hermitian systems in photonics have gained significant attention for the possibility of asymmetric mode-switching and omni-polarizer action through dynamic encirclement of exceptional points (EPs). By introducing the concept of encirclement emulators and utilizing simple configurations to mimic the physics of encircling EPs, linear asymmetric mode-switching and omni-polarizer action can be easily achieved with similar performance and limitations, providing a new perspective for applications in non-Hermitian photonics.