SKIN RESEARCH BY SCATTERING ELLIPSOMETRY
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For citation: Bulykina A.B., Ryzhova V.A. Skin research by scattering ellipsometry method. Scientific and Technical Journal of Information Technologies, Mechanics and Optics, 2017, vol. 17, no. 5, pp. 753–760 (in Russian). doi: 10.17586/2226-1494-2017-17-5-753-760
Application possibility of quantitative ellipsometry method for studies of optical anisotropy and structural heterogeneity of the skin in vivo is shown. To describe the polarization properties of the depolarizing optically-active biotissue medium, the Mueller matrix algebra is used. Based on comparative analysis of the technical options and their application in experiments with biotissue, a setup for recording of the polarization state of the backscattered radiation was developed. It is proposed to use the emitting channel of the LEF-3 ellipsometer in the optical scheme of the stand to have a uniform intensity distribution along the cross section of the input radiation beam, and also to form the polarization states necessary for the study. Radiation source wavelength selection in the spectral range (He-Ne laser, 632 nm) is justified, when scattering of radiation in turbid biological media predominates over absorption that makes it possible to estimate the structural parameters of the sample by the change of the output radiation polarization state. The receiving channel of the output polarization state analyzer was developed; it contains a video information block based on a color matrix sensor with a unified analysis field providing the possibility of further multispectral studying of the skin surface structure. The method of ellipsometric examination of the skin is proposed based on the distribution visualization of the polarization state parameters along the cross section of the output radiation beam and on its following analysis. An algorithm and software are developed with a Python language for image processing and calculation of the polarization characteristics of the sample. The distributions of the polarization characteristics of the skin sector containing scar structures are obtained in the backscattering mode of probing laser radiation.
Acknowledgements. Research is carried out according to R&D No. 615868 «Research of methods and design concepts of automated video information systems for products, objects and materials quality control»