Nonreciprocal unidirectional and circular transmission in microcavity exciton polaritons

We investigate nonreciprocal transmission in microcavity exciton polaritons and obtain analytical conditions for achieving unidirectional and circular transmission. The phase difference between two effective optomechanical couplings can regulate the interference of different channels between two photon modes, and control the direction of nonreciprocity, resulting in unidirectional forward and backward transmissions. Perfect nonreciprocal unidirectional transmission with zero losses is realized, which depends on exciton–photon–phonon couplings. Moreover, clockwise and counterclockwise circular transmissions are implemented by appropriately adjusting the phase of photon mode couplings. Our results open up exciting possibilities for implementing nonreciprocal photonic devices.