Watt-level passively Q-switched mode-locked YVO4/Nd:YVO4 laser operating at 1.06 µm using graphene as a saturable absorber

Abstract High-quality monolayer graphene films with large area were grown on Cu foils by the chemical vapor deposition (CVD) technique. For the first time, graphene saturable absorbers (SAs) with well-defined layer numbers were fabricated by controlling of transfer process precisely. Using the graphene SAs, stable Q-switched mode-locking pulse trains with a nearly 100% modulation depth were realized in a diode-pumped YVO 4 /Nd:YVO 4 laser. At the pump power of 6.0 W, the average output power reached a high value of 1.6 W. To the best of our knowledge, this is the highest output power of passively mode-locked solid-state laser using graphene SA, suggesting that the low-cost, broadband graphene SA could potentially be employed in practical high-power mode-locking laser system.