Sagnac effect of excitonic polaritons

We theoretically treat the Sagnac effect of excitonic polaritons in bulk material and microcavity. Using the coupling between the electromagnetic and excitonic waves, the rotational sensitivity per unit area of a Sagnac loop can be tuned from light to exciton behavior by varying frequency. We also discuss the feasibility and the difficulties of the hybrid light-exciton wave Sagnac interferometer. We show that the quasi-two-dimensional microcavity excitonic polariton is a better candidate than the bulk one. Considering the short decoherence time in semiconductors, we suggest using the degenerate four-wave mixing of the microcavity excitonic polaritons to generate two intrinsically coherent conjugate waves.