Optical properties of new two-photon-pumped lasing dyes

The new dyes, trans-4-(p-pyrrolidinyl styryl)-N-methyl pyridinium methyl sulfate (PSPS) and trans-4-[p-(N,N-diethylamino) styryl]-N-methyl pyridinium methyl sulfate (DEASPS) have been synthesized, and their optical properties were experimentally investigated. These new dyes are stilbene-type pyridinium salts that contain two parts: the highly conjugated cation and the anion. Pumped by a 1064 nm, ∼40 ps mode-locked Nd:YAG laser pulse, these two dyes showed two-photon pumped (TPP) up-conversion lasing locating at ∼600 nm. Experiments have demonstrated that the central wavelengths of TPP lasing have largely influenced by the π-conjugated dye cation, whereas the anion has contribution to enhancing the TPP lasing efficiency. Meanwhile molecular environments have much more effect on both the peak wavelength and the TPP lasing efficiency.