Graphene, due to its linear energy band structure and the Pauli blocking principle, exhibits broadband optical saturable
absorption. We experimentally demonstrated the saturable absorption in graphene with different layers at 800 nm. By
performing the balanced twin-detector method, we are able to characterize the nonlinear optical property of the
as-fabricated different layer graphene samples. Under strong illumination, we find that absorption of graphene decreases
with the increase of incident power, and by fitting the experiment data with theoretical model, the saturable intensity and
the normalized modulation depth is measured to be 7.911 GW/cm2 and 10.6% in 3 layers sample and 2.77 GW/cm2 and
73.6% in monolayer sample, respectively. The experimental result shows that graphene may be a promising saturable
absorber, with the potential laser photonics applications, such as laser mode locker or Q-switcher, at 800 nm band.