Generation of 1.08–1.17 μ stimulated radiation in polymethine dye solutions

An investigation was made of the spectral and laser characteristics of six polymethine dyes. Efficient stimulated emission was obtained in the spectral range 1.08–1.17μ. when these dyes were pumped with neodymium laser radiation. Nitrobenzene was found to be the best solvent from the point of view of stability and efficiency of laser action. The influence of the transverse inhomogeneity of the pump beam on the efficiency of stimulated emission in a longitudinal pump configuration was determined. When a highpower homogeneous pump beam was used and the resonator was characterized by optimal coupling, the efficiency of conversion of the pump radiation reached 30 % for dye solutions with quantum efficiencies in the range 1–2 %.