Ultrafast nonlinear optics due to electron-hole plasma in bulk semiconductors

Abstract

It is theoretically demonstrated that, in the presence of an electric potential landscape, the ground-state energy of the electron-hole plasma can be substantially lowered against the ground-state energy of the excitations. The electron-hole plasma is found to be unstable at lower carrier densities. The critical carrier density for the transition between these two states can be reduced. This reduction provides a new mechanism of nonlinear optics for bulk direct band-gap semiconductors, with picosecond relaxation time, large nonlinearity, and requiring low pump intensity.