Abstract

Dielectrics containing nanometre-size semiconductor crystallites (‘quantum dots') exhibit unique electrooptical and nonlinear-optical properties. The nonlinear-optical behaviour of semiconductor-doped glass in the region of the absorption band edge has been studied extensively.¹ The nonlinearity in this region arises mainly from saturation of the interband absorption. Here we report, for the first time to our knowledge, the observation of large picosecond refractive nonlinearity in semiconductor-doped glass at infrared wavelengths in the high-transparency region far below the band edge. This nonlinearity is thought to arise mainly from the optical Sark effect, and evidence is found for large enhancement due to three-dimensional confinement

© 1990 Optical Society of America