Investigation of conditions for conversion of laser radiation in binary dye mixtures

A theoretical analysis is made of lasing conditions in a binary donor-acceptor mixture of organic dyes pumped by laser pulses in a nonselective resonator. The conditions are found for lasing in one and two bands, and a study is made of the competition between mechanisms of excitation energy transfer from a donor to an acceptor under these conditions. An expression is obtained for the optimal acceptor concentration in conversion of laser radiation in a binary mixture of dyes into frequency-tunable coherent radiation with a large Stokes shift. It is shown that optimal conversion conditions are obtained in a two-band lasing regime. The results of an experimental study are shown to be in good agreement with the theoretical calculations.