Two Photon Pumped Upconversion and Nonlinear Optical Properties of a New Lasing Dye: DEASPI

The two-ephoton pumped frequency upconversion optical properties and the two-photon absorption (TPA) induced nonlinear absorption of a new dye trans-4-[p-(N,N-diethylamino)styryl]-N-methylpyridinium iodide (abbreviated as DEASPI) have been experimentally investigated. This new dye exhibits strong superradiation properties when the pumping power is above the threshold. Furthermore, the superradiation upconversion efficiency and the nonlinear absorption at different wavelengths have been measured. The largest effective molecular TPA cross section was measured to be 3.9 x 10^-47cm⁴.s/photon at 930 nm. At 1064 nm, it was 3.85 x 10^-48cm⁴.s/photon, much smaller than that at 930 nm. The highest upconversion efficiency is 7.57% at 1020 nm, whereas 4.5% at 1064 nm.