Monte Carlo Simulations of Signal Contrast Mechanisms in Broadband Terahertz Polarimetric Imaging of Biological Tissues

Terahertz techniques have promising applications in biological and medical diagnosis. Polarimetric imaging systems are useful for enhancing imaging contrasts, yet the interplay between THz polarization changes and the random discrete structures in biological samples are not well understood. We perform Monte Carlo and Mie scattering simulations of the propagation of the THz waves in skin tissue with embedded structures, such as hair follicles and sweat glands. We show that the polarimetric contrasts are distinctly affected by the sizes and dielectric constants of the scatterers, as well as the frequency and polarization of incident waves. We describe the experimental requirements for extracting these polarimetric signal contrasts due to the low energy and small angular spread of the backscattered THz radiations.