Comparative study of electronic and orientational nonlinear refractive indices with nonlinear ellipse rotation measurements

Abstract

We investigated the contribution of molecular orientation nonlinearity to the nonlinear ellipse rotation (NER) effect. There is an enhancement of 2.25 when this process is compared to pure electronic third-order effects. NER measurements were performed with picosecond laser pulses in SF6 glass and CS2 that respectively present mostly electronic and orientational nonlinearities. A Z-scan was also performed to probe the Kerr-lens signal. The enhancement effect can be understood by taking into account the tensor nature of the third-order susceptibility.