GRAPHENE Under high energy Appl. Phys. Lett. 96, 051122 (2010) Despite intense research into the preparation and characterization of graphene, there have been few studies into its suitability for applications in photonics. Graphene may have significant advantages over carbon nanotubes for ultrafast photonic applications, including a much lower level of saturable absorption, ultrafast recovery times (~200 fs) and a wide operating spectral range that covers the whole telecommunications band. Now, Yong-Won Song and colleagues from the Korea Institute of Science and Technology have used graphene as an intracavity passive power-modulating element, demonstrating efficient laser pulsation in the high-pulse-energy regime. The researchers have overcome the problem of optical power-induced thermal damage by ensuring evanescent field interaction between the propagating light and the graphene layer. The resulting passively mode-locked fibre laser has a central wavelength of 1,561.6 nm, a spectral width of 1.96 nm, a repetition rate of 6.99 MHz and an estimated pulse duration of 1.3 ps. These results suggest that graphene could be useful in ultrafast photonics.
