Highly efficient, powerful Nd:YAG laser CW mode-locked with a monolayer CVD graphene saturable absorber mirror

Graphene-mode-locked solid-state lasers usually have a low optical efficiency (<10%) or a low output average power (<1W) due to losses in the graphene saturable absorber and the thermal load of the laser crystal. We demonstrate what we believe to our knowledge is an improved design for a highly efficient, powerful, diode-end-pumped Nd:YAG laser mode-locked with graphene. Internal losses of the laser cavity were minimized by using a high-quality monolayer graphene saturable absorber applied directly on the cavity end mirror. In comparison to other graphene-mode-locked solid-state lasers, the record high optical-to-optical and slope efficiencies of 19.1 and 24.5%, respectively, in a continuous wave mode-locking regime were achieved. The highest output average power was as high as 1.7 W for the ultrashort pulse repetition rate of 82 MHz at the beam quality of M 2 =1.3×1.4.