Abstract

Tissue coagulation is used in a variety of medical laser treatments. Since typical exposure times are in the 0.1-1-s range, thermal diffusion limits the spatial localization that can be achieved. Better spatial confinement of the thermal effects produced could lead to more precise clinical treatments with a lower risk of complications in a variety of medical applications, e.g., in the eye and in skin. It is clear from basic principles and has been proved experimentally that using single pulse exposure times comparable to the thermal relaxation time of the light absorbing target leads to substantial reduction of collateral thermal damage¹ (Fig. 1). In the pulse duration regime below 1 ms, however, thermomechanical and acoustical effects start to compete with pure thermal effects because of rapid heating and acoustic wave generation in the absorbing targets.²

© 1990 Optical Society of America