Inverted optical bistability and optical limiting in coherently driven exciton-polaritons

Exciton-polaritons in optical cavities exhibit strong nonlinearities predominantly because of the third-order Kerr-like interactions mediated by the excitonic component. Under quasi-resonant excitation, depending on the energy of the incident laser, it results in the optical limiting or bistable behavior. The latter phenomenon is manifested by the hysteresis loop observed in the input-output power characteristics, when a cavity is quasi-resonantly driven by a laser field. The direction of the loop is typically counterclockwise when increasing and subsequently decreasing the optical power. In this work, we demonstrate the optical bistability with an inverted hysteresis direction. It is observed in an exfoliated CdTe-based semiconductor microcavity when the frequency of the pumping laser is tuned slightly below the lower polariton mode. This unusual behavior is caused by the interplay of the suppression of strong coupling and the redshift of the lower polariton mode energy when increasing the incident power. We show that under these conditions, the polariton microcavity can be used as an optical limiter. All of the experimental observations, the shape and the direction of the hysteresis and the optical limiting behavior, are fully supported by a theoretical model.

Automated summary

Exciton-polaritons in optical cavities exhibit strong nonlinearities primarily due to third-order Kerr-like interactions mediated by the excitonic component. Under quasi-resonant excitation, this results in optical limiting or bistable behavior, characterized by hysteresis loops in input-output power characteristics. In this study, we demonstrate the inverted hysteresis direction in an exfoliated CdTe-based semiconductor microcavity, caused by the interplay of strong coupling suppression and the redshift of the lower polariton mode energy. We show that the polariton microcavity can be used as an optical limiter under these conditions, and all experimental observations are supported by a theoretical model.