利用相位敏感的改良HBT方案测量样本复透射系数及厚度的方法

Method for Measuring Phase of Complex Transmission Coefficient and Thickness of Sample by using Phase-sensitive Modified HBT Scheme

在相位敏感的改良Hanbury Brown-Twiss(HBT)方案中,热光散斑图包含样本的复透射系数的振幅信息和相位信息.基于此特性,本文提出了一种测量样本的复透射系数及样本厚度的方法.研究结果表明,在样本粗糙程度较小的情况下,通过加入厚度已知的定标层以增加约束条件,就可以从散斑图中提取样本不同位置处的复透射系数,尤其是其相位信息,从而可以计算相对应的样本厚度.计算精度取决于从散斑图中提取的信息量,提取越多,测量越精确.

In the phase-sensitive modified Hanbury Brown-Twiss(HBT) scheme,the thermal light speckle pattern contains the amplitude and phase information of the complex transmission coefficient of the sample.Based on that,here we propose a method to measure the complex transmission coefficient and the thickness of the sample.It’s shown that when the roughness of sample is small,the complex transmission coefficient,especially its phase,at different positions of the sample can be extracted from the speckle pattern by adding calibration layers with different thicknesses,so that the corresponding sample thickness can be calculated.The calculation accuracy depends on the amount of information extracted from the speckle pattern.The more information is extracted,the more accurate the measurementis.The research on speckle information extraction,especially the extraction of phase distribution information contained in speckle,is very valuable for practical applications.