Abstract

Since the original application of optical heterodyne detection (OHD) techniques in nonlinear optics (NLO) by Ippen and Shank in 1975,^[1] OHD has become a powerful tool for time-resolved NLO spectroscopies. In particular, the recent development of powerful Four- ier-transform/deconvolution methods for extracting the impulse frequency response of transparent materials from femtosecond NLO transients is a direct consequence the unique characteristics of OHD measurements.^[2] In light of these developments, the full capability of OHD techniques in transient spectroscopies has not been developed fully, and there has been some debate in the recent literature as to the relative merits of OHD and non-OHD (quadratic) spectroscopies. In this paper we present quantitative measurements of both quadratic and OHD optical Kerr effect (OKE) transients for some molecular liquids, obtained under identical experimental conditions. These results reveal the distinct advantages of OHD techniques for the extraction of meaningful molecular dynamics information from femtosecond NLO transients.

© 1992 IQEC