This letter demonstrates an efficient high-power high-brightness 2-\mu m continuous-wave (CW) laser with double-end, diffusion-bonded Tm, Ho:YVO4 crystal cooled with liquid N2. The reduction in thermal stress in the composite Tm, Ho:YVO4 rod enabled the laser to achieve a laser output power of 23.4 W at 2.05 \mu m, which is 1.37 times higher than that of the non-composite Tm, Ho:YVO4 rod. The corresponding slope efficiency is 37.3% and the optical-optical conversion efficiency is 35.4%. The beam quality M2 factor is about 1.85 at 20 W output level with circularly symmetric beam spot.
© 2013 Chinese Optics LettersPDF Article