Hyper-Rayleigh Scattering and Two-Photon Absorption-Induced Fluorescence of Chromophores with Enhanced Thermal Stability

Hyper-Rayleigh scattering (HRS) technique has been frequently used to determine chromophore's β values.1 Comparing with the electric field induced second harmonic generation (EFISH) technique, the HRS technique offers a straightforward method for measuring the first hyperpolarizabilities of organic molecules. Recently, HRS from some molecules excited with the fundamental radiation at 1064 nm wavelength has been found to be accompanied by the two-photon absorption (TPA) induced fluorescence.2-3 Consequently, the β value determined by the HRS technique without making appropriate corrections for the contribution due to TPA induced fluorescence could be too large. To obtain the correct β value, the TPA induced fluorescence must be discriminated or removed from the HRS signal.