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Two-Photon-Absorption Induced Superradiance of a New Organic Dye PSPS

The linear and nonlinear optical properties of a new two-photon absorption (TPA) dye, trans-4-(4'-pyrrolidinyl styryl)-N-methyl pyridinium methyl sulfate (abbreviated as PSPS) is reported. Intense red superradiance with a peak located at 625nm can be observed from PSPS solution in benzyl alcohol when pumped by a focused picosecond laser beam operated at 1064nm. The lifetimes of one-photon absorption (OPA) and TPA fluorescence were measured to be 370 and 384ps, respectively. The pulse widths of OPA and TPA superradiance were 60 and 58 ps, respectively. The highest net upconversion efficiency from the absorbed pump laser to the upconverted superradiance is 8.3% at the pump energy of 0.6 mJ.