We report a long-time working femtosecond laser using metal-free sapphire-based graphene as a saturable absorber (SA). The sapphire-based graphene yielded excellent nonlinear saturable absorption properties and was demonstrated to be suitable as an SA for an ultrafast solid-state laser. Stable mode-locked pulses of 325 fs were obtained at a central wavelength of 1032 nm with a repetition rate of 66.3 MHz. At pump power of 8.23 W the average output power was 1.78 W and the highest pulse energy reached 26.8 nJ with a peak power of 72.6 kW. Our work opens up a facile route for making reliable graphene SA in the mode-locking technique and also displays an exciting prospect in making low-cost and ultrafast lasers.
© 2014 Optical Society of America
Lasers and Laser Optics
Original Manuscript: February 24, 2014
Revised Manuscript: March 24, 2014
Manuscript Accepted: March 26, 2014
Published: April 25, 2014
S. C. Xu, B. Y. Man, S. Z. Jiang, D. J. Feng, S. B. Gao, C. S. Chen, M. Liu, C. Yang, C. Zhang, D. Bi, F. Y. Liu, and X. Meng, "Sapphire-based graphene saturable absorber for long-time working femtosecond lasers," Opt. Lett. 39, 2707-2710 (2014)