Coherent control of ballistic photocurrents in multilayer epitaxial graphene using quantum interference.

Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109-2099, USA.
Nano Letters (Impact Factor: 13.03). 03/2010; 10(4):1293-6. DOI: 10.1021/nl9040737
Source: PubMed

ABSTRACT We report generation of ballistic electric currents in unbiased epitaxial graphene at 300 K via quantum interference between phase-controlled cross-polarized fundamental and second harmonic 220 fs pulses. The transient currents are detected via the emitted terahertz radiation. Because of graphene's special structure symmetry, the injected current direction can be well controlled by the polarization of the pump beam in epitaxial graphene. This all optical injection of current provides not only a noncontact way of injecting directional current in graphene but also new insight into optical and transport process in epitaxial graphene.

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