A tunable bistable device based on a coupled quantum dot-metallic nanoparticle nanosystem

摘要

We theoretically propose a scheme of a tunable bistable device based on a coupled semiconductor quantum dot-metal nanoparticle nanosystem in the simultaneous presence of a strong pump laser and a weak probe laser with different frequencies. The results show that it is easy to turn on or off the optical bistable effect in such system by switching the polarization direction of the pump field, and the bistability thresholds are highly sensitive to the intensity, frequency, polarization direction of the pump field, and the interparticle distance. In addition, the nonlinear absorption in the two stable states exhibits a ratio as high as 10(4) arising from the three-photon effect, which implies that our nanosystem can also be used as an optical memory cell.