Exciton-related nonlinear optical absorption and refractive index change in GaAs–Ga1−xAlxAs double quantum wells

In this work the variations of the exciton-related optical absorption and the change of the refractive index in a GaAs–(Ga,Al)As double quantum well as functions of the geometric parameters of the heterostructure are investigated. The variational method is applied within the framework of the parabolic band and effective mass approximations, in order to obtain the 1s-like exciton energy spectrum. The outcome for the related optical coefficients shows a quenched and redshifted light absorption as a result of the increment in the inner barrier and right-hand well widths, with the possibility of an enhancement of the excitonic contribution to the relative change in the refractive index.