Influence of the solution concentration on the efficiency of dye lasers

An experimental investigation was made of the influence of the concentration of a lasing dye in an active medium with an optimal optical density on the efficiency of longitudinally pumped lasers. An increase in the dye concentration above a certain value reduced the lasing efficiency. An analysis was made of possible reasons for this behavior: it was found that the results could be explained by the convergence of the lasing thresholds in the longitudinal and transverse (relative to the pump beam) directions with the losses due to light scattering in the nonlinearly absorbing medium (these losses originated from thermal transient selfdefocusing and also from stimulated thermal scattering).