Abstract

Reliable, high power CO₂, YAG, and Ar ion lasers are common medical instruments, having become the tool of choice in surgical applications as delicate as the repair of detached retinas and as coarse as the removal of polyps from the colon. For these lasers, the destruction of the selected tissue is a thermal process. The laser is simply a convenient means for delivering a sufficient amount of power to the required area to effect pyrolysis. Although obviously quite useful, it belies the impression of the laser as a superbly precise instrument since thermal decomposition is a rather dirty and crude process in terms of the reaction products and the inability to prevent damage to adjacent tissue. If, however, the excitation wavelength is lowered to the UV region below ca. 300 nm the decomposition mechanism changes. Instead of being limited to exciting vibrations and rotations in the exposed material, radiant energy is deposited into the covalent bonds of the biopolymer molecules, causing their direct fragmentation.

© 1988 Optical Society of America