Ray tracing of optically modified fiber tips. 2: laser scalpels

The spatial irradiance distribution of tapered fibers and tapered rods used as scalpels in laser surgery has been calculated by ray tracing. The results were compared to measurements in air and in water. The beam profiles of laser scalpels were conically shaped at discrete angles related to the number of reflections within the scalpel. Light started to leak radially out of the scalpel before it reached the tip slightly suppressing the increase in fluence rate toward the tip. For effective tissue cutting, the scalpel tip may be shortened to optimize the irradiance increase in combination with radial energy leakage to obtain controlled hemostatic coagulation.