Influence of Self-Diffraction Effect on Femtosecond Time-Resolved Single-Shot Optical Kerr Measurements

Femtosecond time-resolved single-shot optical Kerr gating (OKG) measurements are performed by focusing the probe pulse and using a cylindrical lens to introduce a spatially encoded time delay with respect to the pump pulse. By measuring the pump power and polarization dependence of the OKG signals in CS₂, the contribution of self-diffraction effect which is independent of the nonlinear response time of the material is directly observed on the rising edge of the time-resolved OKG signals. The influence of the self-diffraction effect on the optical Kerr signal could be controlled effectively by varying the polarization angle between pump and probe pulses.