激光功率密度对低浓度若丹明6G染料激射寿命的影响

把固体染料激光器工作介质激射寿命的概念推广到液体染料激光器中,同时提出了一种针对液体激光染料激射寿命的双激光光路测试方法.该方法使用波长为532 nm的Nd:YAG脉冲激光器作为抽运光来模拟染料激光器中的抽运条件,用波长相同的低功率连续激光作为监测染料分子在抽运光作用下失效速率的手段.利用半导体制冷器件,PID温控仪和水浴槽实现了液体染料的恒温控制.测量了激光平均功率密度从6.3×103～2.2×104 W/m2变化范围内R6G染料乙醇溶液的激射寿命.实验结果表明,染料的激射寿命与抽运光功率密度成反比,比例系数可以解释为染料分解一半时,分子单位吸收截面上累积的辐照能量.用该系数表征染料的激射寿命特征更具有普遍意义.

Effect of Laser Power Density on Lasing Lifetime of Low Concentration Rhodamine 6G

The concept of the lasing lifetime of working substance in the solid dye laser is promoted to liquid dye laser, and a twin laser beam testing method to measure the lasing lifetime is presented. Nd:YAG laser with the wavelength of 532 nm is used as the pumping source to simulate the pump condition in the dye laser. Low-power continuous-wave (CW) laser with the same wavelength is used to monitor the inactivation velocity of the dye molecules under the effect of pumping laser. Semiconductor refrigeration device, PID temperature control device and the water-bath are used to realize the thermostatically control of the dye solution. Lasing lifetime of Rhodamine 6G alcohol solution is tested while laser power density varies from 6.3×103 W/m2 to 2.2×104 W/m2. The experimental result indicates that the lasing lifetime of Rhodamine 6G is inversely proportional to the pumping laser power density. The proportional coefficient can be explained as the irradiation energy accumulated on unit molecule absorption cross section, when half of the dye molecules are dissociated. It is more convenient to use this coefficient to characterize the lasing lifetime of dye.