Determination of the first hyperpolarizability of multiphoton fluorescent nonlinear optical chromophores via hyper-Rayleigh scattering using fluorescence quenching

The standard hyper-Rayleigh scattering technique is not well suited to dete rmine the first hyperpolarizability beta of molecules which fluoresce at th e second-harmonic frequency. In the past, this problem has been circumvente d by taking advantage of the fact that fluorescence only occurs at longer t imes, whereas the HRS signal can be detected instantly. Thus, time-resolved experiments have to be performed, which requires very costly experimental equipment. In this paper, we present a much simpler method, which is to sup press the disturbing fluorescence by adding a quencher. (C) 1999 Elsevier S cience B.V. All rights reserved.