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

The standard hyper-Rayleigh scattering technique is not well suited to determine the first hyperpolarizability β of molecules which fluoresce at the second-harmonic frequency. In the past, this problem has been circumvented by taking advantage of the fact that fluorescence only occurs at longer times, 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 suppress the disturbing fluorescence by adding a quencher.