Wavelength Dispersion of Two-Photon Absorption and Two-Photon Induced Fluorescence of Stilbazolium Derivatives

摘要

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-(l-methylpyrryl)vinyl]-1-methylpyridinium iodide (MPVPI), trans-4-(2-pyrrylvinyl)-l-methylpyridinium iodide (PVPI), and trans-4-styry 1-1-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