Near-field spectroscopy of graphene during ultrafast photoexcitation

ORAL

Abstract

Recently, impressive progress in nanoplasmonics of graphene using near-field spectroscopy and imaging has been reported [Z. Fei et al., Nano Lett. 11, 4701 (2011); Z. Fei et al., Nature 487, 82 (2012)]. However, these studies of the interaction of the graphene plasmon with the SiO2 substrate surface phonon were time-independent. Here we combine imaging and material characterization on the nano scale with ultrafast sub-picosecond time resolution and present optical pump broadband mid-infrared probe spectroscopy of graphene. We discuss the optical pump induced changes of the coupled plasmon-phonon modes with respect to carrier density and time-dependence. The difference between ultrafast photoexcitation and conventional electrostatic doping via the field effect is analyzed and compared with modeling.

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Authors

  • Martin Wagner

    • University of California San Diego
    • University of California, San Diego

  • Zhe Fei

    • University of California San Diego

  • Alexander McLeod

    • University of California San Diego

  • Aleksandr Rodin

    • University of California San Diego

  • Wenzhong Bao

    • University of California Riverside

  • Lingfeng Zhang

    • Boston University

  • Zeng Zhao

    • University of California Riverside

  • Eric Iwinski

    • University of California San Diego

  • Mark Thiemens

    • University of California San Diego

  • Michael Fogler

    • University of California San Diego

  • Antonio Castro-Neto

    • National University of Singapore

  • Chunning Lau

    • University of California Riverside

  • Fritz Keilmann

    • Max Planck Institute of Quantum Optics

  • Dimitri Basov

    • University of California San Diego