Optical current generation in graphene: CEP control vs. <i>ω</i> + <i>2ω</i> control

Abstract The injection of directional currents in solids with strong optical fields has attracted tremendous attention as a route to realize ultrafast electronics based on the quantum-mechanical nature electrons at femto- attosecond timescales. Such are usually result an asymmetric population distribution imprinted by temporal symmetry driving field. Here we compare two experimental schemes that allow control over amplitude and direction light-field-driven excited graphene. Both rely shaping incident laser field one parameter only: either carrier-envelope phase (CEP) single pulse or relative between pulses oscillating angular frequencies ω 2 , both for comparable parameters. We observe efficiency generating current via two-color-control exceeds CEP more than orders magnitude (7 nA vs. 18 pA), + exhibits significantly asymmetry its shape. support this finding numerical simulations clearly show two-color graphene is superior, even down single-cycle durations. expect our results be relevant experimentally access fundamental properties any solid timescales, well emerging petahertz electronics.