Room-temperature optical bistability has been demonstrated in hydrogenated amorphous silicon at wavelengths greater than about 700 nm. Switching powers as low as 0.8 mW (switching intensities 1.7 kW/cm2) are observed. The measured switching times are found to be compound, with time constants from 50 μs to 1 ms.
Optical bistable devices containing GaAs/AlGaAs multiple quantum well (MQW) structures have shown great potential for performing fast low-power optical switching at room temperature.1 The presence of a much stronger exciton absorption feature in the MQW structures compared to bulk GaAs suggests far superior performance in the former. We report the observation of room-temperature bistability in bulk GaAs with input power <10 mW and intensities of a few kW/cm2. The intensities are consistent with the data of Miller et al.2 which show a saturation intensity of nearly 4 kW/cm2 in a MQW sample with a detuning of less than a halfwidth from the peak of the exciton resonance. Our detunings are always several halfwidths.