Experimental Study For Laser Dye's Lasing Lifetime In Laser Isotope Separation

The dye laser is a key equipment in Atomic Vapor Laser Isotope Separation (AVLIS), which performance can directly influence the economy and reliability of AVLIS. The photochemical stability of the dye is one of important technical indicators of the lasers. In order to establish the estimation system on photochemical stability of the dye, and to analyze the influences of laser power, repeat frequency of pulse, temperature and assistant reagent on the photochemical stability, it is of great significance to explore the method to ameliorate the photochemical stability for the development of the AVLIS.This thesis focuses on the testing of laser dye's lasing lifetime. Based on the theoretical analysis of the dye and the photo-induced fluorescence, a new method for testing the liquid laser dye's lasing lifetime was introduced. In this method, Nd:YAG laser, with the wavelength of 532 nm, was used as the pumping source to simulate the pump condition in the dye laser; while the low-power continuous wave laser with the same wavelength was used to monitor the inactivation velocity of the dye molecules under the effect of pumping laser. A semiconductor refrigeration device, a PID temperature control device and a water-bath were employed to achieve the thermostatically control of the dye solution. By using the uniquely designed experimental system, lasing lifetimes of four different kinds of Rhodamine dyes under various conditions were measured. The rules of experiments were summarized based on the experimental results, and were analyzed. The conclusions obtained from these experiments are of great importance for the actual applications of dye lasers in AVILS. All the experiments carried out in this thesis were miniature and simulative according to the working situation of laser dyes in AVLIS.From the experiments, the pump laser's average power density, temperature were found to have different influences on the dye'lasing lifetime. The experimental results showed that the dye's lasing lifetime changes with the laser power density and temperature. In the experiments, the influence of triplet state quencher on dye's lasing lifetime was also tested. Two triplet state quenchers which can ameliorate dye's lasing lifetime effectively were found.