Chiral microresonator assisted by Rydberg-atom ensembles

Abstract

The chiral light-matter interaction, which shows great potential in applications ranging from photonic devices to quantum information processing, can be achieved with the development of recent experimental advances of the fabrication technologies on nanoscales. Traditionally, the chiral optics based on spin-momentum locking in micro- and nanophotonics could be observed only for specific optical modes, such as the transverse magnetic mode. Here in this study, we investigate that the chirality of a whispering-gallery-mode (WGM) microresonator can be well controlled with assistance from coupled Rydberg-atom ensembles. The presented asymmetric backscattering also originates from interferences between scattered optical modes in the WGM microresonator, which is proposed by Wiersig [Phys. Rev. A 84, 063828 (2011)]. Therefore the flow of light can be well controlled, and the statistical properties of photons could be changed by regulating this asymmetric coupling. Most importantly, its universal chiral property is not limited by specific optical modes which may also be used as optical diodes and routers.