Abstract

Semiconductor heterostructures have been designed to investigate interference in absorption between electronic subbands. The conduction band profile of such structures generates a potential which satisfies the Fano conditions for observing interference between a bound state and the continuum. All the relevant parameters, i.e. the escape rate Γ and the matrix element to the continuum are tadorable and controlled by design. Moreover, by applying an electric field to the structure, we are able for the first time to change the density of state of the continuum and therefore to investigate the intermediate regime of intersubband transition lineshapes between a bound-coupled-to-continuum and a bound-coupled-to-bound excited state.

© 1996 Optical Society of America