Fig. 1. (a) Photograph of the end facet of the Ho:YAG SCF. (b) Schematic of the Ho:YAG SCF laser: L1–L3, lenses with , 100 and 150 mm, respectively; M1, M2, bending mirrors; M3, dichroic mirror; PM, pump mirror; OC, output coupler.

Fig. 2. (a) Laser performance of the Ho:YAG SCF laser with different OCs and (b) the corresponding optical spectra. The gray curves are the calculated gain spectra of Ho:YAG^[17] with different population inversion parameters .

Fig. 3. Caird plot for the high-power Ho:YAG SCF laser: inverse slope efficiency with respect to the inverse output-coupling loss, i.e., .

Fig. 4. Beam intensity profiles recorded at different output powers with ; is the calculated beam ellipticity from each image.

Fig. 5. (a) The measured -factor of the Ho:YAG SCF laser () at different absorbed pump powers and (b) a typical measurement at 7 W output laser power.