Controllable amplification, absorption, and dispersion in double-cascade-type four-level system of multiple quantum wells

A double‐cascade‐type four‐level system of semiconductor multiple quantum wells (MQWs) was constructed with biexcitons and excitons. The nonlinear optical properties for amplification, absorption, and dispersion of 2‐weak fields in this scheme are investigated. It shows that the amplification, absorption, and dispersion responses of 2‐weak fields can be achieved by appropriately adjusting the relative phase, the probe detuning, and the two control Rabi frequencies. The investigation is much more practical than its atomic counterpart because of its flexible design and the widely adjustable parameters. It may provide a new possibility in technological applications for the light amplifier and optical switch working on quantum coherence effects in MQW solid‐state systems.