Study on Ultrafast Dynamic Behaviors of Different Nonlinear Refractive Index Components in CS 2 Using a Femtosecond Interferometer

We investigated time responses of components parallel n 2 /\kern-2p t/ (t) and perpendicular n 2 ⊥(t) to pump polarization of the nonlinear refractive index in CS2 and its dilute solutions using a femtosecond time division interferometer. The temporal profiles of n 2 /\kern-2p t/(t) and n 2 ⊥(t) were decomposed into the electronic, fast- and slow-decay nuclear contributions based on the response time. The magnitudes, signs and time constants of these three contributions of n 2 /\kern-2p t/(t) and n 2 ⊥(t) were also evaluated with high accuracy. Moreover, the n 2 /\kern-2p t/ (t) and n 2 ⊥(t) measurements in the dilute CS2 solutions showed that the ratio between the fast-decay contributions of time responses of n 2 /\kern-2p t/ (t) and n 2 ⊥ (t) was the same value as that between the slow-decay contributions. This result is explained using a cluster model.