LONG-WAVELENGTH FIRST HYPERPOLARIZABILITY MEASUREMENTS BY HYPER-RAYLEIGH SCATTERING

A hyper-Rayleigh scattering (HRS) system based on an optical parametri c power oscillator is described. The first hyperpolarizability, beta, of Crystal Violet dye was measured at 1450 and 1500 nm. The resonance- free beta value, beta(0), for this octupole was found to be comparable with that of the dipolar dye Disperse Red 1 but with the nonlinearity -transparency trade-off worse for the octupole. The discrepancy in bet a(0) with that reported previously is explained in terms of resonance and the adequacy of the octupolar three-state model. The possibility o f dye aggregation by solvent-dependent HRS is investigated. (C) 1996 O ptical Society of America