Abstract

The nonlinear-optical (NLO) properties of semiconductors confined in three dimensions, often called semiconductor quantum dots, have been the subject of intense study. Semiconductor doped glasses can be fabricated which exhibit quantum size effects due to the confinement of the photoexcited carriers by the insulating glass matrix. We have previously reported the fabrication¹ of Cu(I)Cl quantum dots in a borosilicate glass matrix with radii ranging from 20Å to 35 Å and the measurement² of the third order nonlinearity of the CuCl quantum dots due to saturation of the excitonic absorption at 380 nm. The CuCl quantum dots exhibit an extremely large, size dependent, nonlinearity at resonance. In this paper we report the femtosecond dynamics of the third order NLO response of CuCl quantum dots in borosilicate glass measured in a transparent region of the glass far from resonance. The measurements were performed with 90 femtosecond time resolution (60 fsec pulses) using a four wave mixing configuration which is capable of separating the electronic and nuclear contributions to the NLO susceptibility³.

© 1992 Optical Society of America