Tissue Optics and Photonics: Light-Tissue Interaction II

This is the third part of the review-tutorial paper describing fundamentals of tissue optics and photonics. The first part of the paper was mostly devoted to description of tissue structures and their specificity related to interactions with light [1]. The second part presented light-tissue interactions originated from tissue dispersion, scattering, and absorption properties, including light reflection and refraction, absorption, elastic, and quasi-elastic scattering [2]. This last part of the paper, underlines mostly photothermal and nonlinear interactions such as temperature rise and tissue damage, photoacoustic and acoustooptical, nonlinear sonoluminescence, Raman scattering, multiphoton autofluorescence, second harmonic generation (SHG), terahertz (THz) radiation interactions, and finally photochemical interactions with description of two widely spread therapeutic applications: photodynamic therapy (PDT) and low level light therapy (LLLT).