Acta Photonica Sinica, Volume. 46, Issue 4, 412001(2017)
Effects of Small-scale Surface Roughness and Absorption on Refractive Index Measurement by the Brewster-angle and Critical-angle Techniques
Small-scale roughness on surface is equivalent to a multilayer structure with same thickness and gradient refractive index. By using characteristic matrixes, the reflectivity of P waves of the effective multilayer model with different incident angle is calculated; the refractive index of the absorbing medium is a complex number in the calculation of Fresnel formula; COMSOL Mutiphysics is used to model and simulat the small-scale roughness and absorption. The calculation results show that both the small-scale roughness and absorption of the dielectrics can make errors in measurement of the refractive index. In conclusion, in order to get the precision of 10-5 , the refractive index of rough dielectrics should be measured by critical-angle technique, while it is better to measure absorbing dielectrics by Brewster-angle technique.
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ZHANG Xiao-bao, LUO Hui, TAN Zhong-qi, LIU Wen-bin, WU Su-yong. Effects of Small-scale Surface Roughness and Absorption on Refractive Index Measurement by the Brewster-angle and Critical-angle Techniques[J]. Acta Photonica Sinica, 2017, 46(4): 412001
Received: Oct. 20, 2016
Accepted: --
Published Online: May. 3, 2017
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