Investigating Multi-Layer Media Using Optical Spectroscopy: Modeling and Experimental Methods

Author: Luka Tsulukidze
Keywords: Photons, photon diffusion, Monte Carlo methods, spectroscopy, detrended fluctuation analysis, photoplethysmography, spectral analysis
Annotation:

Within the framework of the paper, we discussed the modeling of the propagation of light in a multi-layer environment using the Monte-Carlo method, which enabled us to investigate the optical characteristics of different environments. Our goal was to compare the human skin reflectance spectra obtained experimentally by our group (TSU Modeling Student Laboratory and Cybernetics Institute Optics Department) with the results obtained through the model. The simulated spectra match the experimentally obtained results, through which we learn the optical characteristics of healthy human skin. In addition, we observed anomalous and normal photon diffusion modes in multilayer, homogeneous, anisotropic and isotropic media, and compared the diffusion coefficients obtained analytically and through our model, we obtained a match with high accuracy. Also, our goal was to process the PPG signals recorded by our group, which represent modulations of light intensity reflected from human skin. For this, we used spectral analysis (Fourier and wavelet analysis) and other complex processing methods, such as detrended fluctuation analysis.