Phase change of an ultrashort laser pulse transmitting through a ZnSe single crystal in a pump-probe experiment

We built a Ti-sapphire ultrashort laser-pulse pump-probe experiment system combined with a spectral interferometer as a detection apparatus. We measured the spectrum when the probe pulse interfered with the reference pulse as the pump pulse irradiated a 0.5 mm thick ZnSe single crystal. We analyzed the interference spectrum by using a Fourier transform method and obtained information on the change in the phase of the probe pulse due to changes in the transient properties of the sample. We found that the group-delay dispersion and the third-order dispersion of the probe pulse showed nonlinear variations as a function of the time delay between the pump pulse and the probe pulse.