利用扫描法测量预制棒折射率

Investigation of scan to measure the distributing of refraction ratio of section plane

通过对现有测试方法的分析,提出了一种新的测量方法——细光束扫描来测量预制棒的折射率分布。细光束照射到预制棒上,预制棒就像是柱透镜使光线会聚,光线在预制棒中经过一系列的折射后,最后从另一端出射。在假定预制棒内折射率分布的基础上,应用几何光学中的折射定律对扫描光线进行追迹,计算其在预制棒内的传播路径,得到理论上出射的位置,通过测量可以得到实际光线出射的位置,利用这两个结果的差异构造评价函数,运用蒙特卡罗算法对假定的折射率分布进行反复的修正,最后评价函数趋向于一个很小的值,此时折射率分布也趋向于其真实分布,达到测量的目的。

A new measure method is described——the technique of thin beam scan to measure the distributing of refraction ratio of section plane after analyzing measure methods in existence.When thin beam irradiated section plane,the light is converged because of the section plane like columnar lens.After pass by a series of refract empress inside section plane,the light pass through section plane and out of the other side.Firstly,the distributing of refraction ratio of section plane is supposed.Secondly,the contrail of thin beam with refraction law in geometrical optics based on the supposition is calculated.Finally,the light dipping location of theoretic is obtained.At the same time,the light dipping location of practicality is obtained by experiment.An evaluation function with difference of two result can be constructed.And the supposition of the distributing of refraction ratio of section plane by Monte-Carlo method can be corrected time after time.At last the evaluation function value will get very little and the distributing of refraction ratio of section plane is obtained.