Fig. 1. (a) Fluorescence spectrum of a Yb:LuScO₃ crystal; crystal thickness is 1 mm. (b) The calculated fluorescence line shape F for multiphonon-assisted transitions; n represents the phonon number.

Fig. 2. Experimental setup of the tunable laser beyond 1.1 µm on Yb:LuScO₃ crystal.

Fig. 3. (a) Wavelength tuning curve for the Yb:LuScO₃ crystal at the incident pump power of 5.1 W. The tunable spectrum is discontinuous. (b) Tunable laser spectra in the range of 1121–1136 nm. The bandwidth is narrow below 0.1 nm, which is consistent with the CW laser operation.

Fig. 4. Raman spectra of Yb³⁺-doped Lu₂O₃, LuScO₃, and Sc₂O₃ crystals. Two main Raman peaks of Yb:LuScO₃ crystal are 405 cm^-1 (A_g mode) and 472 cm^-1 (E_g mode).

Fig. 5. (a) Experimental setup of the CW laser at 1131 nm; (b) characterizations of laser in the Yb:LuScO₃ crystal; output power as a function of absorbed pump power; inset, CW laser spectra of Yb:LuScO₃ with T_oc = 0.1%.