SPECTRAL MEASUREMENTS OF HYPER-RAYLEIGH LIGHT-SCATTERING

An apparatus is described for the measurement of second-order nonlinea r optical properties via hyper-Rayleigh scattering with 1 cm(-1) spect ral resolution of the scattered light. The setup allows a complete inv estigation of the polarization dependence of the second-harmonic scatt ered light. The combination of good spectral resolution, polarization analysis, and high sensitivity allows the determination of accurate po larization ratios of the scattered light. Consequently, information on the relative magnitude of hyperpolarizability components may be infer red from the measurements. Liquid phase measurements of a number of pu re organic solvents including substituted benzene compounds are report ed with approximately 5% uncertainty in the relative scattered intensi ties. Vapor phase measurements are also possible using the same appara tus, allowing a separation of the intrinsic molecular nonlinearities f rom contributions to hyper-Rayleigh scattering due to intermolecular i nteractions. (C) 1996 American Institute of Physics.