Nonlinear optical properties of solgel-derived glasses doped with copper selenide nanoparticles

Transient differential absorption spectra of solgel glasses that contain co pper selenide nanoparticles (NP's) have been studied with a picosecond pump -probe technique. Oxidation of copper selenide NP's results in the appearan ce of an additional absorption band peaked at similar to 1 mu m, which can be transiently bleached under laser excitation. Excited-state absorption re lated to mid-gap surface trap states was observed. The absorption recovery time was found to be similar to 300 ps. The intensity-dependent transmissio n of oxidized copper selenide NP's in solgel glass at 1.08 mu m has been me asured. Permanent laser-induced absorption changes in the glasses were stud ied with nanosecond pulses as a function of laser exposure. Passive Q switc hing of 1.06-mu m Nd3+:Y3Al5O12, 1.34-mu m Nd3+ :YAlO3, and 1.54-mu m Er3: glass lasers has been realized with the glasses containing copper selenid e NP's used as saturable absorbers. (1.34 mu m),Q-switched pulses with 100- ns (1.06 mu m), 90-ns (1.34 mu m) and 60-ns (1.54 mu m) pulse widths were o btained. (C) 2000 Optical Society of America. [S0740-3224(00)01904-4] OCIS codes: 140.3540, 160.6060, 320.7130.