Optical bistability via tunable Fano-type interference in asymmetric semiconductor quantum wells

We analyze hybrid absorptive-dispersive optical bistability (OB) behavior via tunable Fano-type interference based on intersubband transitions in asymmetric double quantum wells (QWs) driven coherently by a probe laser field by means of a unidirectional ring cavity. We show that OB can be controlled efficiently by tuning the energy splitting of the two excited states (the coupling strength of the tunnelling), the Fano-type interference, and the frequency detuning. The influence of the electronic cooperation parameter on the OB behavior is also discussed. This investigation may be used for optimizing and controlling the optical switching process in the QW solid-state system, which is much more practical than that in atomic system because of its flexible design and the controllable interference strength.