Bulk growth and an efficient mid-IR laser of high-quality Er:YSGG crystals
Herein, bulk single crystals of Er:Y3Sc2Ga3O12 (Er:YSGG) with a maximum diameter of 35 mm or a maximum length of 100 mm were successfully grown by the Czochralski method using a 60 mm diameter crucible. The high-resolution X-ray diffraction and optical interferometry results indicated that the as-grown crystals were of high quality. The crystalline perfection of the as-grown crystal was evaluated to be 20.58′′ via the FWHM of the rocking curve, and the optical homogeneity RMS was in the order of 10−6. A continuous wave laser of the Er:YSGG crystal operating at 2798.7 nm has been demonstrated. Moreover, a maximum output power of 745 mW has been realized. The achieved maximum slope efficiency is 31.5%, which is, to date, the highest slope efficiency in the Er:YSGG crystal lasers operating at ∼2.8 μm.