Abstract

Optical bistability in the presence of an optically induced absorption is observed when a thin 13-μm CdS sample is inserted between two mirrors of 90 % reflectivity, in our experiment, a modulated cw laser of ~15-mW peak power is tuned on each side of the free exciton resonance in CdS, and the transmission characteristics are studied. A theoretical calculation including both absorptive and dispersive effects is presented and good agreement is obtained. The absorption coefficient and the index of refraction of the material are connected by Kramers-Kronig relations. Propagation effects are taken into account. Sufficiently long pulses (40 ms) are considered to allow the thermally induced absorption to occur. For detunings above the free exciton resonance, we predict that counterclockwise hysteresis loops will first be observed as the intensity rises; for detunings below the free exciton resonance, only clockwise hysteresis loops are predicted. These predictions were experimentally verified. Power levels of the order of 5–10 mW were sufficient to observe bistability. Cavity effects were also observed.

© 1985 Optical Society of America