Abstract

Hyper-Rayleigh and hyper-Raman light scattering (HRS) were among the first nonlinear optical (NLO) phenomena to be investigated both theoretically and experimentally.¹,² A revival of interest in this technique has occured as it is a more general method of investigating the second order NLO properties of molecules.³ The HRS experiment allows the characterization of molecules having dipolar or octupolar symmetry, in contrast to electric-field induced second harmonic generation (EFISH), in which only species having dipolar symmetry may be probed.⁴ Moreover, if a polarization analysis is made of the scattered light, relative ratios of the components of the second order NLO polarizability tensor may be determined.⁵,⁶ In this work we report evidence for the collision-induced modulation of HRS. We find that is necessary to consider the intermolecular collision contribution to HRS in order to obtain accurate ratios of the first (β) hyperpolarizability components. Vapor phase HRS measurements are also reported, where the vapor phase intensities are directly compared with the liquid phase intensities. Local field factors are able to correct for the differences between vapor and liquid phases for the intramolecular contribution to HRS.

© 1995 Optical Society of America