Abstract

Coherent mid-infrared sources are of prime importance for different studies involving vibrational spectroscopy in biomolecules or intersubband optical transitions in semiconductors. Recently, we developed a new mid-infrared femtosecond light source based on optical rectification of 15-fs light pulses in bulk GaAs.¹ However, many other nonlinear optical materials can also be used as optical rectifiers for mid-infrared generation. Multiple quantum well (MQW) structures are especially interesting systems since they can be engineered to produce tailored mid-infrared radiation. Up to now, the generation of tunable infrared pulses has been demonstrated in the far- infrared domain only, based on the coherent charge oscillation between two coupled quantum wells.² Here, we make use of the coherent charge oscillation in an asymmetric quantum well after excitation by a 15-fsec optical pulse, to produce mid-infrared radiation.

© 1996 Optical Society of America