Creath K, Wyant J C
Appl Opt. 1990 Sep 10;29(26):3823-7. doi: 10.1364/AO.29.003823.
In an interferometer which uses a reference surface, the measured surface heights correspond to the difference between the test and reference surfaces. To accurately determine the rms roughness of supersmooth surfaces, the effects of the reference surface roughness need to be removed. One technique for doing this involves averaging a number of uncorrelated measurements of a mirror to generate a reference surface profile which can then be subtracted from subsequent measurements so that they do not contain errors due to the reference surface. The other technique provides an accurate rms roughness of the surface by taking two uncorrelated measurements of the surface. These two techniques for measurement of supersmooth surfaces are described in detail, and results of the measurement of a 0.7-A rms roughness mirror are presented. The expected error in the rms roughness measurement of a supersmooth mirror due to instrument noise is 0.02 A.
在使用参考面的干涉仪中，测量的表面高度对应于测试面与参考面之间的差值。为了准确测定超光滑表面的均方根粗糙度，需要消除参考面粗糙度的影响。一种实现此目的的技术是对镜子进行多次不相关测量并求平均值，以生成参考面轮廓，然后从后续测量值中减去该轮廓，这样后续测量值就不会包含因参考面导致的误差。另一种技术是通过对表面进行两次不相关测量来提供表面准确的均方根粗糙度。本文详细描述了这两种测量超光滑表面的技术，并给出了对均方根粗糙度为0.7埃的镜子的测量结果。由于仪器噪声，超光滑镜子均方根粗糙度测量中的预期误差为0.02埃。
