应用可调谐外腔半导体激光器测量锂同位素比率

摘要

The technology of laser absorption spectroscopy was used for lithium isotope ratio measurement. A tunable external cavity diode laser, operating at a fixed center wavelength, was used as an optical source. The measurement and control of lithium metal evaporation temperature was achieved by the PID temperature controller. The using of laser oblique incidence eliminates the influence of etalon effect in the optical path. The absorption spectra of 6Li and 7Li near 671 nm were recorded at six different cavity temperatures. The 6Li/7Li isotope ratio was retrieved from the integrated absor-bance of 6LiD1and 7LiD2. Experiment results show that the best accuracy of lithium isotope ratio is 2. 5%.%采用中心波长固定的可调谐外腔半导体激光器作为光源,通过激光吸收光谱法对锂原子同位素比率进行测量.该方法利用PID温控器实现锂金属蒸发温度的控制和测量.采用激光斜入射的方式消除光路调试过程中产生的标准具效应.实验测量给出了6组不同腔体温度下6 Li和7 Li在671 nm附近的吸收光谱,通过对6 LiD1和7LiD2吸收峰进行积分吸收计算,得到6Li/7Li同位素比率测量精度可达2.5％.