Excited state absorption and laser emission from infrared laser dyes optically pumped at 532 nm

Abstract

Efficient near-infrared dye laser emission has been achieved in the 838–923-nm range by use of a frequency-doubled Nd:YAG laser as the optical pump for various polymethine dyes. Experimental evidence of 1064-nm quenching of the dye laser emission is reported. Strong excited state absorption (ESA) effects are observed for the dye IR-140 at the 532-nm pump wavelength. This excited state absorption results in an experimentally determined optimum pump power density of 50–60 MW/cm2 for maximum dye laser efficiency. Such excited state absorption may thus be a limiting factor in the power scaling of pulsed dye lasers.