  Graphene is at the center of a significant research effort. Near-ballistic
transport at room temperature and high mobility make it a potential material
for nanoelectronics. Its electronic and mechanical properties are also ideal
for micro and nanomechanical systems, thin-film transistors and transparent and
conductive composites and electrodes. Here we exploit the optoelectronic
properties of graphene to realize an ultrafast laser. A graphene-polymer
composite is fabricated using wet-chemistry techniques. Pauli blocking
following intense illumination results in saturable absorption, independent of
wavelength. This is used to passively mode-lock an Erbium-doped fibre laser
working at 1559nm, with a 5.24nm spectral bandwidth and ~460fs pulse duration,
paving the way to graphene-based photonics.
