Kinetics of laser emission from lamp-pumped rhodamine 6G solutions

An investigation was made of the spectral-time characteristics of the laser emission from rhodamine 6G solutions pumped with pulses up to 340 J-energy. The leading edges of the pump pulses were 1, 6, and 17 μsec. The concentrations of the solutions were 0.01–1 g/liter. An analysis of the time dependences made it possible to determine the influence of the induced losses which were due to the triplet-triplet absorption and which shifted the emission spectrum in the direction of shorter wavelengths. This analysis also yielded the losses due to the absorption in the photoreaction products, which shifted the spectrum in the direction of longer wavelengths. The competition between these losses resulted in complex changes of the spectrum with time. The conditions for the emission of a stable laser band were determined. A method was developed for the determination of the intercombination conversion constant k_ST and of the triplet lifetime τ_T from the time dependence of the emission wavelength.