Transmittance Bistability of CdS at 632.8 nm Induced by the 514.5 nm Line

For the first time, we demonstrate that irradiation of CdS with a 514.5 nm argon line causes the formation of an all-optical bistable loop in the transmitted power of the 632.8 nm He-Ne line at 300 K. The effect is due to a nonlinearity in the transmittance created by the known trap level of pure CdS situated 0.52 eV below the conduction band.