STUDIES OF 2-PHOTON PUMPED FREQUENCY-UP-CONVERTED LASING PROPERTIES OF A NEW DYE MATERIAL

The two-photon absorption (TPA), TPA-induced frequency upconversion em ission, and two-photon-pumped (TPP) lasing properties of a new dye, ra ns-4[p-(N-hydroxyethyl-N-methylamino)stryryl]-N- methylpyridinium iodi de (abbreviated as ASPI) were experimentally investigated. This new dy e has a moderate TPA cross section (sigma(2) approximate to 3.9X20(-20 ), cm(4)/GW in benzyl alcohol), but exhibits a low lasing threshold an d high lasing efficiency when pumped with a 1064 nm pulsed laser beam. Furthermore, the TPA-induced fluorescence yield is strongly dependent on the polarity of the solvent, making it a promising dye for sensing applications. The spectral, temporal, and spatial structures as well as the output/input characteristics of the TPP cavity lasing and the s uperradiant (cavityless) lasing are systematically measured using a 1 cm path quartz cuvette filled with the ASPI solution or a doped polyme r rod. The net conversion efficiency from the absorbed 1064 nm pump pu lse energy to the similar to 615 nm upconverted cavity lasing energy w as found to be as high as similar to 17%. (C) 1997 American Institute of Physics.