Two-photon absorption and optical limiting properties of organic salt trans-4-[p-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium iodide in various solvents

The absorption spectra, single-photon induced fluorescence spectra, two-photon absorption (TPA) and optical limiting behaviors of organic dye trans-4-[p-(N-hydroxyethyl-N-methylamino)styryl] -N-methylpyridinium iodide (abbreviated as ASPI) have been studied in three solvents [chloroform, benzyl alcohol, dimethyl formamide (DMF)] with different polarities. The optical properties of ASPI were found to be strongly influenced by the solvents used. With increasing polarity of the solvents, the absorption and fluorescence peaks of ASPI solutions exhibit marked blue and red shifts, respectively, and the effective TPA cross sections and the optical limiting effects decrease. The TPA cross sections of ASPI measured in the three solvents are 3.41 x 10(-47) (chloroform), 1.86 x 10(-48) (benzyl alcohol) and 1.05 x 10(-41) (DMF) CM4 .s.photon(-1).