Abstract

Quantum dots of CdS prepared in silicate glass hosts by sol–gel techniques have been studied by using subpicosecond degenerate four-wave mixing. TEM analysis of the samples shows particle sizes in the range of 34 to 53 Å. The four-wave mixing experiments were conducted off-resonance, and the signals exhibited intensities and decay times that varied with microcrystallite size. In general, biexponential decays were observed with faster decay times recorded for the smaller sizes. Self diffraction arising from the interaction between any two input laser beams was also observed. Relative measurements of the intensity in adjacent orders establish χ⁽³⁾ values in the range of 10⁻¹⁰ esu for laser pulses of subpicosecond duration.

© 1992 Optical Society of America