迈克尔逊干涉仪影响因素的测量不确定度分析

Analysis of Uncertainty in Measurement of Michelson Interferometer

用测量不确定度分析方法,通过理论分析和数值计算,指出人工目测读数、动镜法线与移动方向不一致、M1和M2′不严格平行以及长度测量的A类测量不确定度是影响迈克尔逊干涉仪测量的主要因素,理论分析与实验结果符合。①M1和M2′严格平行时,若采用人工目测读数,则计数误差是最主要的影响因素,动镜法线与移动方向不一致以及urel(Δd)A也是较大影响因素,urel(Δd)B影响较小;②M1和M2′不严格平行,有微小的夹角θ,则ucrel(Δd)θ、urel(Δd)A以及urel(Δd)α,β三者为同一数量级,都是主要影响因素;③为提高测量精度,首先要提高干涉条纹计数精度,同时要调整M1和M2′严格平行,且动镜法线与移动方向保持一致。在空气膜厚d>20 mm区域测量,不宜在d=0 mm附近区域测量。

With the analysis of uncertainty in measurement,this article pointed out that the artificial visual counting,inconsistency between the normal of moving mirror with the moving direction,M1 is not strictly parallel to M′2,as well as type A evaluation of uncertainty in measurement of length are the main impact factors of Michaelson interferometer through theoretical analysis and numerical calculation.① When M1 and M′2 are strictly parallel and artificial visual counting is used,the counting error is the most important factor,the inconsistency between moving direction and moving mirror normal as well as urel(Δd)A also are the main impact factors,while urel(Δd)B is less affected;② When M1 is not strictly paralleled to M′2,and there is a slight angle θ,then ucrel(Δd)θ,urel(Δd)A and urel(Δd)α,β which are the same order of magnitude are the main factors;③ To enhance the accuracy of measurement,the interference fringe counting accuracy should be improved,at the same time the M1 should be adjusted to be strictly parallel to M′2,and the moving mirror normal and the direction of movement should be kept consistent.And Michelson interferometer should be used within the limits of air film thickness d>20 mm,not around the limits d=0 mm.