Extracting spectral parameters of materials is an essential application of terahertz spectroscopy technology, based on the characteristics of coherent detection. However, the commonly used algorithm for extracting spectral parameters requires a parallel and smooth surface as a prerequisite, and the surface roughness will affect the extraction result. Nevertheless, the effect degree and the mechanism are not precise before. Firstly, in this research, optical parameters of samples with different roughness extracted by the algorithm are displayed. Therefore, the effect degree of different roughness on the optical extraction algorithm is clarified. After that, the mechanism of the influence is analyzed through the method of microelement modeling. As a result, it shows that when the sample surface is slightly rough (roughness<60μm), it will not significantly impact the extraction results. The shape of the optical curve will not be significantly distorted. As the roughness increases, the change of the statistical distribution of the Fresnel coefficient and the phase change are the reason for the attenuation of the terahertz wave amplitude and the decrease of the extraction accuracy.

Date Published: 9 September 2021
PDF: 6 pages
Proc. SPIE 11909, Tenth International Symposium on Ultrafast Phenomena and Terahertz Waves (ISUPTW 2021), 119090D (9 September 2021); doi: 10.1117/12.2604346

Published in SPIE Proceedings Vol. 11909:
Tenth International Symposium on Ultrafast Phenomena and Terahertz Waves (ISUPTW 2021)
Liguo Zhu; Xiao Cheng; Daiming Ma, Editor(s)