fiber bundle and the optical window and penetrates into the patient 39 s skin since the optical window is approximately 1 5 mm thick the window also serves as a spacer between the output end of the fiber bundle and the skin of the patient thus as the laser light is emitted from each fiber in the bundle the light is permitted to diverge as it travels through the window to the patient 39 s skin in a preferred embodiment the fibers are approximately 100 200 microns in diameter and the beam emitted from each fiber after passing through the window produces a spot between 150 900 microns in diameter on the patient 39 s skin because of the diverging nature of light emitted from an optical fiber the light at the center of each spot will be relatively high energy light while the light at the periphery of each spot will have significantly lower energy thus over a combined spot size of 7 to 10 mm for the entire fiber bundle there are approximately 1000 to 2000 smaller treatment spots generally about 150 900 microns in diameter each consisting of a higher fluence u201c hot spot u201d at the center of the spot surrounded by a lower fluence u201c cooler zone u201d of radiation the energy at the central u201c hot spot u201d is sufficient to shrink the underlying tissue.