Stone Jack A, Amer Mohamed, Faust Bryon, Zimmerman Jay
National Institute of Standards and Technology, Gaithersburg, MD 20899-0001.
J Res Natl Inst Stand Technol. 2004 Jun 1;109(3):319-33. doi: 10.6028/jres.109.024. Print 2004 May-Jun.
We have studied a number of effects that can give rise to errors in small-angle measurement systems when they are used to calibrate artifacts such as optical polygons. Of these sources of uncertainty, the most difficult to quantify are errors associated with the measurement of imperfect, non-flat faces of the artifact, causing the instrument to misinterpret the average orientation of the surface. In an attempt to shed some light on these errors, we have compared autocollimator measurements to angle measurements made with a Fizeau phase-shifting interferometer. These two instruments have very different operating principles and implement different definitions of the orientation of a surface, but (surprisingly) we have not yet seen any clear differences between results obtained with the autocollimator and with the interferometer. The interferometer is in some respects an attractive alternative to an autocollimator for small-angle measurement; it implements an unambiguous and robust definition of surface orientation in terms of the tilt of a best-fit plane, and it is easier to quantify likely errors of the interferometer measurements than to evaluate autocollimator uncertainty.
我们研究了一些在使用小角度测量系统校准诸如光学多边形等工件时可能导致误差的影响因素。在这些不确定度来源中，最难量化的是与工件不完美、非平面表面测量相关的误差，这会导致仪器误判表面的平均方向。为了深入了解这些误差，我们将自准直仪测量结果与用菲佐相移干涉仪进行的角度测量结果进行了比较。这两种仪器的工作原理截然不同，对表面方向的定义也不同，但（令人惊讶的是）我们尚未发现自准直仪和干涉仪所获结果之间存在任何明显差异。在某些方面，干涉仪是用于小角度测量的自准直仪的一个有吸引力的替代方案；它根据最佳拟合平面的倾斜度对表面方向给出了明确且可靠的定义，并且相比于评估自准直仪的不确定度，量化干涉仪测量的可能误差更容易。
