Abstract

Optical bistability (ob) is investigated in CdS in a wide range of intensities. Under pulsed excitation (total pulse width 20 nsec) we find at 5K for ħω_exc ≈ 2.550 eV on the flank of the AΓ₅ exciton ob of the induced absorption type for incident intensities of I_exc ≈ 1kW/cm². The nonlinearity is in this case a collision-broadening of the free exciton resonance [1]. The commutation times τ↓ and τ↑ are about 1 nsec and 5 nsec, respectively. For ħω_exc ≈ 2.546 eV we observe absorptive ob due to the formation of an electron-hole plasma [2] for I_exc ≈ 1MW/cm². Single shot experiments show τ↓ ≲ 500 psec being thus to our knowledge one of the shortest commutation times reported for single beam ob so far. The observed hysteresis loops are compared to model calculations with variable pulse lengths. The comparison indicates true ob in our experiments.

© 1985 Optical Society of America