Radiative coupling effects on intersubband absorption in double quantum wells

Based on the fact that the imaginary part of the optical susceptibility is no longer valid to present the absorption in multiple quantum wells due to radiative coupling among wells, and to get better understanding of the radiative coupling process, absorption in two non-electronically coupled quantum wells is investigated via a microscopic local-held theory for intersubband transitions. It has been found that the radiative coupling basically acts as a perturbation to the absorption of a single well, and is a function of e(iq perpendicular to Delta). Numerical simulations show that even in two quantum wells the radiative coupling can play an important, the relative absorption difference can be as big as similar to 20% of the absorption.