Calculated efficiency of dye lasers as a function of pump parameters and triplet lifetime

The rate equations governing pulsed laser operation in dyes have been solved numerically and the results discussed for a variety of material parameters and pump conditions, especially for pulses in excess of 1 μsec. The resulting laser parameters have been considered as a function of the triplet lifetime and the pump peak power. Calculated values of the efficiency in the conversion of pump light into laser light have been derived in general, and applied specifically to the case of Rhodamine 6G. The calculated efficiencies have been compared with known experimental results on Rhodamine 6G under laser and flashlamp excitation. The agreement is generally good. Since the predicted efficiencies for laser operation in excess of a few hundred nanoseconds depend critically on the values of the triplet lifetime τp in solution, especially for τp in the range 100–300 nsec, the results of the calculations can be reliably compared to experiment only when precise values of the triplet lifetimes become experimentally available.