用标准具测量微小频移的方法研究

Method study of measuring tiny frequency-shift using etalon

针对光学系统表面反射激光和水中受激布里渊散射光通过F-P标准具后所形成的干涉环簇图样,提出了三种计算布里渊频移的方法,即小角度微分法、小角度差值法和环间距比例法。分别对其进行了理论推导,得出了相应的解析表达式,并通过实验进行了验证。使用这三种方法得出的结果分别为8.65GHz,8GHz和7.2GHz,其中由环间距比例法得出的结果与水中布里渊散射频移的理论值7.5GHz符合得最好。通过与已有方法进行比较,结果表明与环间距比例法相差1MHz。分析了各种方法的优缺点以及适用情况和条件。

Three methods for calculating the tiny frequency-shift between the light reflected by optical surface and scattered by water are presented. They are small angle differential method,small angle difference method and ratio of space between rings method. The corresponding analytical expressions are derived,the results are 8.65GHz,8GHz and 7.2GHz respectively. The 7.2GHz obtaind from ratio of space-between-rings method agrees well with the theoretical value 7.5GHz. The advantages and disadvantages of them as well as the instances and conditions are discussed.