High efficiency and high beam quality Er:YSGG Mid-infrared continuous-wave laser

• An LD end-pumped Er:YSGG mid-infrared (MIR) continuous-wave (CW) laser with high efficiency and high beam quality was demonstrated. • A composite crystal YSGG/Er:YSGG/YSGG with a size of 3×3×14 (2+10+2) mm 3 was employed. • The absorption coefficient and thermal problems of the composite Er:YSGG crystal was optimized based on adjusting the center wavelength of the LD pump source. • The maximum output power of 2.01W was achieved, corresponding to slope efficiency of 28.89%, and the beam quality M 2 of the laser was 1.19. We demonstrated an LD end-pumped Er:YSGG mid-infrared (MIR) continuous-wave (CW) laser based on optimized LD pump wavelength with less absorption coefficient and thermal problems. A composite crystal YSGG/Er:YSGG/YSGG with a size of 3×3×14 (2+10+2) mm 3 was employed, and its central part had an erbium ion doping concentration of 38%. The maximum output power of 2.8 μm MIR laser is 2.01 W, corresponding to a slope efficiency of 28.89%, at which the beam quality M 2 of the laser is 1.19. Compared with other Er 3+ -doped laser, we achieved a CW MIR laser with higher efficiency and better beam quality. The results suggest that optimizing the wavelength of the pump source and adopting the crystal bonding technology could effectively improve the performance of the LD end-pumped Er:YSGG CW MIR laser.