Abstract

The nonlinear optical properties of size quantized excitons within semiconductor microcrystallites are the subject of much current interest. When embedded in glass, quantization of the exciton translational motion occurs in CuCI, leading to quantum size effects such as enhancement of the oscillator strength and the nonlinear refractive index. We report the measurement of the nonlinear refractive index, n₂, at the Z₃ exciton resonance for CuCI quantum dots in borosilicate glass. The optical nonlinearity is measured using a single beam absorption saturation technique. The glass samples were studied at 77K with an excimer pumped dye laser operating from 370 nm to 388 nm. Absorption spectra were obtained as a function of incident laser intensity. At the highest incident intensities the transitions were completely bleached. The nonlinear refractive index is calculated from the saturated absorption spectra using the Kramers–Kronig transformation. Significant enhancement of the nonlinearity over that of bulk CuCI is observed. In addition, a microcrystallite size dependence of the nonlinearity is observed.

© 1990 Optical Society of America