Spectral measurements of hyper-Rayleigh light scattering

An apparatus is described for the measurement of second-order nonlinear optical properties via hyper-Rayleigh scattering with 1 cm(-1) spectral resolution of the scattered light. The setup allows a complete investigation of the polarization dependence of the second-harmonic scattered light. The combination of good spectral resolution, polarization analysis, and high sensitivity allows the determination of accurate polarization ratios of the scattered light. Consequently, information on the relative magnitude of hyperpolarizability components may be inferred from the measurements. Liquid phase measurements of a number of pure organic solvents including substituted benzene compounds are reported with approximately 5% uncertainty in the relative scattered intensities. Vapor phase measurements are also possible using the same apparatus, allowing a separation of the intrinsic molecular nonlinearities from contributions to hyper-Rayleigh scattering due to intermolecular interactions. (C) 1996 American Institute of Physics.