Laser-tissue interactions involve (1) the physical mechanism of interaction [photothermal, photochemical, photomechanical], (2) the biological level of interaction [tissue, organ, cellular, organellar], and (3) the time course of the interaction [immediate physical effect, short-term biological response, long- term healing and structure/function].
S. L. Jacques, "Laser-tissue interactions," SPIE Proceedings of Thermal and Optical Interactions with Biological and Related Composite Materials, edited by M. J. Berry, G. M. Harpole, 1064, 17 (1989).