Time-domain separation of nuclear and electronic contributions to the third-order nonlinearity in glasses

The electronic and nuclear contributions to the third-order nonlinearity of glasses are separated by use of 100-fs pulses in a time-resolved heterodyne optical Kerr effect technique. A direct estimate of the relative strengths of electronic and nuclear contributions was made by the comparison between the nuclear contribution deduced from the Raman spectra with the Kerr signal. The ratio between the electronic and nuclear response functions was ∼5/1 in a tellurium oxide glass sample. The time evolution of the nuclear contribution is in good agreement with results deduced from the Raman spectra.