The spectral and temporal properties of single- and two-photon fluorescence of a dye-doped linear homogeneous polymer are reported. The dopant is a new organic dye, <i>trans</i>-4-[<i>p</i>-(<i>N</i>-hydroxyethyl-<i>N</i>-ethylamino)styryl]-<i>N</i>-methylpyridinium <i>p</i>-toluene sulfonate (HEASPS), synthesized by researchers at the State Key Laboratory, Jinan China. When the dye is excited by near-infrared laser radiation, strong upcoverted fluorescence and superradiance can be observed. The difference in the blueshift of two-photon superradiance compared with that of two-photon fluorescence is explained by the use of different reabsorption coefficients under different conditions. The lifetime of two-photon fluorescence in a solid was measured to be 4.14 ns, which was much longer than that in solution. Two-photon transmittance and upconversion efficiencies at different wavelengths were measured with an optical parameter amplifier as the pump source. The strongest two-photon absorption occurred at 930 nm. The highest upconversion efficiency was 4.05% at 1030 nm. A possible mechanism is discussed.
© 2002 Optical Society of America
(160.4330) Materials : Nonlinear optical materials
(160.5470) Materials : Polymers
(190.4180) Nonlinear optics : Multiphoton processes
(190.4710) Nonlinear optics : Optical nonlinearities in organic materials
Guang-Yong Zhou, Dong Wang, Xiao-Qiang Yu, Yan Ren, Xin-Guang Xu, Xiu-Feng Cheng, Zong-Shu Shao, and Min-Hua Jiang, "Two-photon-absorption and upconverted superradiance properties of organic dye HEASPS-doped linear homogeneous polymer at several wavelengths," J. Opt. Soc. Am. B 19, 1141-1144 (2002)