Optical bistability in nonlinear periodic structures

Abstract

Optical bistability has been predicted to occur in periodic structures with a nonlinear index of refraction. This switching is expected to occur for frequencies within the stop gap of these structures at high intensities. We present the results of an experimental study of optical bistability in a distributive feedback structure with a large, thermal, nonlinear index of refraction. The structure we used was a 100 μm thick colloidal crystal consisting of 86 nm diameter, charged microspheres suspended in a solution of water and an absorptive dye. Optical switching to a highly transmitting state was found to occur at an incident intensity of approximately 300 kW/cm2, while switching back to a low transmitting state occurred at ≈150 kW/cm2. The dependence of the optical switching on the frequency detuning from the center of the stop gap and the time dependence of the switching have been studied, and these results will be presented. Our experimental results are compared to theoretical predictions of the transmission properties of nonlinear periodic structures, and good agreement is found between the theoretical predictions and the experimental results.