Two-photon absorption and nonlinear optical properties of a new organic dye DEASPI

A new organic dye trans-4- [p-(N,N-diethylamino) styryl]-N-methylpyridinium iodide (abbreviated' as DEASPI thereafter) with large two-photon absorptio n (TPA) cross section and excellent upconverted lasing properties was synth esized. The melting point and decompound point were measured to be 230 degr eesC and 264.7 degreesC respectively. The molecular TPA cross section was m easured to be sigma (2)=6.9x10(-48) cm(4).s/photon at 1064 nm by using an o pen aperture Z-scan system. The linear and nonlinear optical properties of this dye were systematically studied. The highest net upconversion efficien cy from the absorbed pump energy to the output upconverted lasing energy is as high as 18.6% at the pump energy of 2.17 mJ from a mode-locked Nd:YAG p s laser. The nonlinear transmittance at the wavelengths from 720 to 1100 nm was measured. The dye solution also shows a clear optical power limiting e ffect.