Abstract

The third-order nonlinear optical susceptibility χ⁽³⁾ of CS₂ on short time scales has been studied extensively, primarily via optical Kerr effect (OKE) measurements.^1,2 We extend these results using degenerate four-wave mixing (DFWM) experiments in a forward geometry. Our experimental setup using 100-fs pulses resembles the OKE geometry but contains an added degree of freedom. The temporal overlap of the two orthogonally polarized collinear (pump) beams and a third noncollinear (probe) beam inside the CS₂ cell are controlled independently. The OKE results (induced birefringence) are reproduced in our experiments for the special case where the two pump beams temporally overlap and the probe arrives subsequently. We also observe a DFWM signal when the probe and either of the pumps overlap in time and the other pump arrives later; this behavior is attributed to phase gratings formed in the Kerr media and is related to different χ⁽³⁾ijkl components.

© 1991 Optical Society of America