Absolute measurement of roughness and lateral-correlation length of random surfaces by use of the simplified model of image-speckle contrast.
Absolute measurement of roughness and lateral-correlation length of random surfaces by use of the simplified model of image-speckle contrast.
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DOI：
10.1364/ao.41.004148
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发表时间：
2003-05
期刊：
影响因子：
1.9
通讯作者：
Chuan-fu Cheng;Chunxiang Liu;Ningyu Zhang;T. Jia;Ruxin Li;Zhi‐zhan Xu
中科院分区：
文献类型：
--
作者：
Chuan-fu Cheng;Chunxiang Liu;Ningyu Zhang;T. Jia;Ruxin Li;Zhi‐zhan Xu
We present a method of image-speckle contrast for the nonprecalibration measurement of the root-mean-square roughness and the lateral-correlation length of random surfaces with Gaussian correlation. We use the simplified model of the speckle fields produced by the weak scattering object in the theoretical analysis. The explicit mathematical relation shows that the saturation value of the image-speckle contrast at a large aperture radius determines the roughness, while the variation of the contrast with the aperture radius determines the lateral-correlation length. In the experimental performance, we specially fabricate the random surface samples with Gaussian correlation. The square of the image-speckle contrast is measured versus the radius of the aperture in the 4f system, and the roughness and the lateral-correlation length are extracted by fitting the theoretical result to the experimental data. Comparison of the measurement with that by an atomic force microscope shows our method has a satisfying accuracy.
