The lifetime of dye molecules is important parameter in the variety of electro-optical applications of organic dyes, for instance, in passive Q-switching, mode-locking etc. The lifetime is critically dependent on physical properties of the solvent.
In the first stage of the research, output characteristics of nitrogen laser and nitrogen laser-pumped Rhodamine 6G dye laser are investigated. The output energy, pulse duration, peak power, beam divergence are measured for the nitrogen laser and Rhodamine 6G dye laser, and optimal lasing conditions are found.
In the later stage of the research, absorption coefficient of Rhodamine B is measured as a function of incident intensity, concentration of Rhodamine B in the etyleneglycol solvent and thickness of the dye solution along the resonator optical axis. Analysis on saturation of gain give the lifetime of $S_1$-level of 7.0 ± 0.7 nsec independent of concentration. Also, the saturation intensity is found to vary from 3.1 × $10^6$/w/㎠ for the Rhodamine B concentration of 2×$10^{-3}$ mole/liter to 1.4 × $10^6$/w/㎠ for the concentration of 2 × $10^{-4}$mole/liter.
