Abstract

Envelope wavefunctions of carriers in semiconductor quantum wells (QWs) typically extend over distances in the few nanometer range. The dipole elements of optical transitions between subband states have thus the same order of magnitude, i.e., the nanometer range instead of the Ångström range usually observed in bulk crystals. Huge second order optical susceptibilities are then expected and measured in intersubband transitions, provided the inversion symmetry is broken.

© 1995 Optical Society of America