Optical bistability and multistability with coupled quantum wells in the presence of second- and third-order nonlinearities

In this work, we explore the intriguing phenomena of bistability and multistability in a cavity comprising two coupled quantum wells via electron tunneling. The cavity is driven by squeezed light produced by an optical parametric oscillator. Our results show that the frequency detunings relative to direct and indirect excitons are crucial for the occurrence of bistability, which is governed by the Kerr effects. Furthermore, we reveal that multistable behavior in the excitonic and photonic intensities can be attributed to the interaction between second- and third-order nonlinearities. We also investigate the controllability of the transition between bistability and multistability. The switch between bistability and multistability is controlled by adjusting the squeezed light’s amplitude or the cavity’s frequency detuning between the external coherent drive and the cavity. The tunneling has a contrasting double impact for the emergence or destruction of bistability and multistability, depending on the consideration of direct and indirect exciton nonlinearities. As a consequence, the switch between bistability and multistability can be ensured also by adjusting the tunneling rate between the wells, which in turn depends on the distance separating them.