  Stable 30 fs pulses centered at 1068 nm (less than 10 optical cycles) are
demonstrated in a diode pumped Yb:CaYAlO4 laser by using high-quality chemical
vapor deposited monolayer graphene as the saturable absorber. The mode locked
8.43 optical-cycle pulses have a spectral bandwidth of ~ 50 nm and a pulse
repetition frequency of ~ 113.5 MHz. To our knowledge, this is the shortest
pulse ever reported for graphene mode-locked lasers and mode-locked Yb-doped
bulk lasers. Our experimental results demonstrate that graphene mode locking is
a very promising practical technique to generate few-cycle optical pulses
directly from a laser oscillator.
