Abstract

Recently, the high speed of semiconductor materials was combined with the large optical nonlinearity of the Franz-Kelydish effect near the quantum confined exciton absorption within semi-insulating multiple quantum well structures (SIMQW)[1]. The diffraction efficiency of four wave mixing obtained in the SIMQW with an optical interaction length of 1.05 µm is comparable with the diffraction efficiency for a semiconductor bulk sample with an optical interaction length of several mm operating under similar conditions. Thus, SIMQW become a ideal candidate to study the diffraction process in the Raman-Nath regime[2]. Here, we report two effects of the second order diffraction in a SIMQW sample under applied field: 1) the direct observation of a strong second order diffraction signal; 2) the intensity of the degenerate four wave mixing signal depends on the direction of applied field when the fringe spacing becomes large.

© 1991 Optical Society of America