Abstract

We study the optical nonlinearities of ZN_.87Cd_.13Te single crystals near their absorption edge, at room temperature. In a pump and probe configuration, the samples are excited above their band gap by pump pulses of about 150ps duration, emitted by a distributed feedback dye laser (DFDL) with 0.1 meV spectral width. This DFDL and a quenched resonator laser (QRL) are pumped by ns pulses from an excimere laser (XeCl). The pulses of the broadband (100 meV) QRL (test beam) are of 100 ps duration and of low intensity. Due to the jitter between pump and test pulses, the overall time resolution is of 350ps. The DFDL pulses pass a variable optical delay (maximum 15ns) and are focused onto the surface of the sample with a maximum intensity of 23MW/cm². Inside this excitation spot of 90µm diameter, the test beam is focused into a spot of 30µm diameter. The respective positions of both spots on the surface of the sample are carefully checked by microscope.

© 1992 IQEC