Highly sensitive setup for tunable wavelength hyper-Rayleigh scattering with parallel detection and calibration data for various solvents

Abstract

A very sensitive experimental setup for accurate wavelength-dependent hyper-Rayleigh scattering (HRS) measurements of the molecular first hyperpolarizability beta in the broad fundamental wavelength range of 600 to 1800 nm is presented. The setup makes use of a stable continuously tunable picosecond optical parametric amplifier with kilohertz repetition rate. To correct for multi-photon fluorescence, a small spectral range around the second harmonic wavelength is detected in parallel using a spectrograph coupled to an intensified charge-coupled device. Reliable calibration against the pure solvent is possible over the full accessible spectral range. An extensive set of wavelength-dependent HRS calibration data for a wide range of solvents is presented, and very accurate measurements of the beta dispersion of the well-known nonlinear optical chromophore Disperse Red 1 are demonstrated.