Abstract

Large phase shifts in semi-insulating multiple quantum wells¹ are observed for dc applied fields much smaller than the space- charge-limited field. As shown in Fig. 1, large phase shifts are obtained experimentally in a set of samples with different quantum barrier heights. This phenomenon cannot be expained by a simple generalization of Kuhktarev's equations. In addition, the phase-shift mechanisms of moving gratings, alternating fields, or the temperature/intensity model² also cannot be applied.

© 1994 Optical Society of America