Abstract
Er: YAG lasers will soon become the most efficient medical lasers, The wave-length of this lasers is 2.94 μm and their ability of incising biotissues is much stronger than CO2 lasers (wavelength: 10.6μm). Our experiments prove that, for example, Er:YAG lasers are able to cut into livers about two times as deep as CO2 laser are. Furthermore, Er:YAG lasers cause much less thermal damage to biotissues than CO2 lasers, because Er:YAG laser beams are more easily absorbed by water than CO2 laser beams are.
For studying possibilities of applying Er:YAG lasers to endscopy. We tested fluoride glass fibers (ZrF4), chalcogenide glass fibers (As2S3), and a hollow light guide all of which may be used in an Er:YAG laser delivery system. The transmittance of the fluoride glass fibers we measured was 90%, at 1m long and the average output power was about 4W at 10pps. Regarding the chalcogenide glass fibers, transmittance was 75% at 1m long, while the average output power was 1.2W at 10pps. The test shows that these fibers are applicable to Er:YAG laser endscopes, although the fibers have a fragile mechanism and some other problems yet to be solved. On the other hand, the transmittance of the A1 hollow light guide measured 64% per meter and the average output power was 1.4W at 10pps. This hollow light guide may be too large to be used for endscopy but it will be applied to surgical laser blades, because it has a rigid mechanism and is able to transmit high power laser.
