Fig. 3.

Schematic representation of Holmium:YAG laser generators. Low-power generators are made out of a single laser cavity (gray box) that emits its laser beam (pink) in line with the output connector and the proximal end of the laser fiber (blue). High-power generators incorporate multiple laser cavities (gray boxes) and require a complex alignment of laser beams (pink) to the output connector for safe transmission to the delivery fiber (blue). A vapor-compression refrigeration system (yellow box) is necessary for cooling of high-power Holmium:YAG generators