Bleaching and diffusion of laser dyes in solution under high power UV irradiation

Bleaching experiments in some laser dyes under high power UV irradiation from a nitrogen laser are described. Very high bleaching quantum efficiencies, of the order of 10^-3 molecules bleached/photon absorbed, and a dependence of this efficiency on intensity have been found. The diffusion coefficients for the dyes in ethyl alcohol were also measured.