Model for temporal z-scan curve evolution in nonlocal nonlinear media under high-repetition-rate laser excitation

In this work, we present a model to describe the temporal evolution of z-scan curves of thin samples when high-repetition-rate lasers are used. A time-dependent nonlinear refractive phase of the saturable type is numerically analyzed. The consideration of the simultaneous participation of two nonlinear responses allows us to describe z-scan curves that can change in sign with time. Different high-order or nonlocal contributions are accounted for to show the main differences obtained in the temporal evolution of z-scan curves. Experimental results for a CS 2 sample were obtained using an fs pulsed laser at a high repetition rate and were fitted with the proposed model. Furthermore, our approach provides a framework to interpret some published results.