Wavelength dispersion of two-photon absorption and two-photon-induced fluorescence of stilbazolium derivatives

Abstract

Organic materials with large two-photon absorption are desired for numerous photonics applications, such as optical limiting,upconversion lasing, three-dimensional data storage,and photodynamic therapy. Stilbazolium derivatives are interesting two-photon absorbers for these applications. In this work,the nonlinear transmissivities of trans -4-[4-(dimethylamino)styryl ]-1-methylpyridinium iodide (DASPI), trans -4-(4-aminostyryl)-1-methylpyridinium iodide (ASPI), trans -4-[2-(1-methylpyrryl)vinyl ]-1-methylpyridinium iodide (MPVPI), trans -4-(2-pyrrylvinyl)-1-methylpyridinium iodide (PVPI),and trans -4-styryl-1-methylpyridinium iodide (SPI)at 800,850,900,950 and 1000 nm have been studied respectively using 21 ps laser pulses. The two-photon induced fluorescence of these compounds at 872,900,and 940 nm has also been investigated.All of these compounds exhibit two-photon absorption and two-photon induced up-converted fluorescence in the near-IR wavelengths,and the two-photon absorption cross section and two-photon induced fluorescence intensity vary with the wavelength and with the chemical structure changes. These preliminary results suggest that it is possible to increase the two-photon absorption cross-sections by proper structure modifications