High-power ultrafast Nd:YVO4 laser mode-locked by graphene saturable absorber

The large-area monolayer graphene film was grown on Cu foil by chemical vapor deposition (CVD) technique. After transferring it to a quartz substrate, the graphene film was used as a saturable absorber (SA) in an Nd:YVO4 laser. Mode-locked laser pulses of 7.6ps were obtained at a central wavelength of 1064nm. Under a pump power of 6.7W, the average output power reached a high value of 2.5W, corresponding to an optical-to-optical efficiency of 37.3% and a slope efficiency of 40.3%. The pulse repetition rate was 87.4MHz and the maximum pulse energy was as high as 28.6nJ. To date, this might be the highest average output power for mode-locked laser by using graphene SA. Our results illustrate that graphene can potentially be employed in the practical low-cost and high-power mode-locking laser system. •The graphene films with large area were fabricated by CVD technique.•The graphene film was used as a saturable absorber (SA) in Nd:YVO4 laser.•Mode-locked laser pulses of 7.6ps were obtained at 1064nm.•The maximum pulse energy was as high as 28.6nJ.