Study of near-infrared semiconductor laser irradiation of biological skin tissues for non-lethal laser thermal dispersion

Non-lethal lasers have attracted considerable interest in both military and biomedical applications owing to their diverse range of functionalities, with thermal dispersion being one prominent application. However, investigations into the interaction mechanisms between non-lethal thermal dispersive lasers and biological tissues remain limited. In this study, a four-layer tissue model representing the biological structure of skin is developed, and the thermal effects of different laser beams on skin tissues are analysed. The dispersion and damage thresholds under laser irradiation are determined using the modified Beer-Lambert law and the Arrhenius equation. Validation through simulation and experimentation, the thermal dispersal threshold of 976 nm laser is measured to be 9.18 W/cm². The paper provides an in-depth explanation of the dynamic equilibrium phenomenon in skin tissue temperature under laser irradiation, incorporating the light source, heat source, blood perfusion, and the multilayer tissue model. This work elucidates the fundamental mechanisms of laser-induced heat diffusion in biological skin tissues, offering valuable insights for the future development of laser-based heat diffusion technologies.