Fig. 1. Schematic diagram of the ceramic fabrication process.

Fig. 2. XRD pattern of the Ho:YAG ceramic.

Fig. 3. SEM image of the Ho:YAG ceramic after thermal etching for 10 h at 1450°C.

Fig. 4. Transmittance spectra of the Ho:YAG ceramic: (a) 200 to 2200 nm (inset, photo of the ceramic); (b) 350 to 600 nm; (c) 1800 to 2000 nm.

Fig. 5. Absorption and emission cross section spectra of Ho3+ in the YAG ceramic.

Fig. 6. Emission spectra of the Ho:YAG ceramic excited at 450 nm.

Fig. 7. Fluorescence lifetime of the Ho:YAG ceramic at 2088 nm.