金属折射率虚部的激光衍射测量方法

在高精度激光衍射法的丝径测量中存在着偏振效应，用Ｓ和Ｐ分量的偏振光入射所得到的丝径测量值不相同．二者之差与金属折射率的虚部有关．在金属狭缝衍射实验中也观察到了这样的偏振效应．木文基于这些实验提出了金属折射率虚部的激光衍射测量方法．细丝直径或狭缝宽度随入射光振动与丝轴或缝边之间夹角变化的实验值经过曲线拟合可以得到金属折射率的虚部ｎｋ的数值，其精度约０．０６。ｎｋ之值与其它方法的测量值在２％相对误差范围符合得很好．

Measurement of the Imaginary Part of Metal Optical Index by Laser Diffraction

The polarization effect appears in the high accuracy measurement of thin wire diameter by laser diffraction. The measuted diameter values obtained by the polarised incident light of S and P components are different. The difference between them is related to the imaginary part of metal optical index. The same polarization effect is observed in metal slit diffraction experiments. Based on these experiments, the measurement of the imaginary part of metal optical index by laser diffraction of thin wires or slits is proposed in the present paper. The curve of the measured wire diameter or slit width varying with respect to the angle between incident light vibration and wire axis or slit edges is fitted into their experimental values. Therefore, the imaginary part nk can.be figured out. Its accuracy is about 0. 06.The values of nk are in good agreement with those of other methods in the range of 2 % relative error. The measurement of uK by laser diffraction is fairly Simple.