Abstract

Intersubband transitions in the conduction band (CB) have been extensively studied, but they suffer from one main drawback: a component of the incoming electric field must lie perpendicular to the quantum wells (QWs). This is not true for the valence band (VB), where mixing of the VB and CB functions at k_║ ≠ 0 allows normal-incidence transitions. Utilization of VB intersubband transitions makes it possible to realize normal-incidence devices that were previously possible only with waveguiding, grazing incidence, or other forms of coupling with CB intersubband transitions. These include such devices as modulators, detectors, and structures for nonlinear-optical applications.

© 1994 Optical Society of America