Linear and nonlinear intersubband optical absorption coefficient and refractive index change in n-type δ-doped GaAs structure

Abstract

In the effective mass approximation, we have theoretically investigated the subband structure of single Si δ-doped GaAs by solving the Schrödinger and Poisson equations self-consistently. Both the linear and nonlinear intersubband optical absorption coefficients and the refractive index changes are calculated as dependent on the doping concentration and thickness. Our results show that the position and the magnitude of the linear and total absorption coefficients and refractive index changes depend on the doping concentration and thickness. The shape of potential profile and the subband energy differences are changed as dependent on the donor concentration and thickness. By considering the variation of the energy difference we can obtain a blue shift or a red shift in the intersubband optical transitions. The resonant peak of total absorption coefficient can be bleached at sufficiently high incident optical intensities. Such a dependence of the exciting optical intensity on the doping concentration and thickness can be very useful for several potential device applications.