Fingerprints of THz-wave scattering in biological tissues: Pilot theoretical and experimental studies

Abstract

Terahertz (THz) technology went through the rapid development during the past few decades. Nowadays, among other advantages, it offers novel opportunities in the label-free diagnosis of malignant and benign neoplasms with different nosologies and localizations. THz solid-immersion high-resolution imaging has demonstrated the possibilities of subwavelength imaging in neurodiagnostics. The observed THz microscopic images showed a heterogeneous character of brain tissues at the scale posed by the THz wavelengths, which is due to the distinct response of white and gray matters, the presence of different neurovascular structures, as well as due to the necrotic debris and hemorrhage in a tumor. The observed results posed the problem of studying the inhomogeneity of brain tissues that causes scattering of THz waves, as well as the urgent need to use the radiation transfer theory to describe the THz-wave – tissue interactions.
To study the scattering of THz waves, a model medium was created, where a gelatin solution acted as an absorbing host medium, and silicon dioxide microspheres acted as nonabsorbing scatterers. Then, the Lorentz-Mie scattering parameters were calculated, and the refractive indices and absorption coefficients were measured experimentally. Comparison of the numerical and experimental results allows us to draw a conclusion about the effect of scattering on the effective THz optical characteristics of the medium.

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Speaker

Anna S. Kucheryavenko
Prokhorov General Physics Institute of RAS; Institute of Solid State Physics of RAS
Russia

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