NONLINEAR PROPAGATION AND SCATTERING OF ELECTROMAGNETIC WAVES IN BIOLOGICAL TISSUES AT THZ FREQUENCIES

Abstract

Examination of nonlinear wave interactions reveals complex challenges and biomedical opportunities arising from the propagation and scattering of electromagnetic waves (EM) at THz frequencies through biological tissues. This study focuses on nonlinear effects like harmonic generation, self-focusing, and scattering. It also discusses the interaction process of THz waves with biological tissues. The model simulating nonlinear tissue dielectric wave behaviors includes absorption and dispersion phenomena that influence the tissue's operating frequency. Detailed tissue microstructure scattering analysis reveals the impact of scattering on wave behavior and overall propagation. Working diagrams, as well as flow diagrams, are provided to demonstrate the process of modeling and estimating THz wave-tissue interactions through the combination of analytical calculations and numerical simulations. Nonlinearities impact signal attenuation and scattering, and are cross-sectionally analyzed to evaluate the THz system's imaging and diagnostic potential. Evaluation experiments, which verify the effectiveness of the solution based on real datasets of tissues exposed, confirm the initial envisioned impact of the solution. Imaging the propagation of terahertz waves through tissues enhances our understanding of wave behavior in biological materials, while improving the development of non-invasive diagnostic devices that utilize THz technology. The research paves the way for further studies of focused ion beam-fabricated microstructures and enables new imaging techniques that enhance existing systems.