• 文献标题:   Ultrafast nonlinear optical response of Dirac fermions in graphene
  • 文献类型:   Article
  • 作  者:   BAUDISCH M, MARINI A, COX JD, ZHU T, SILVA F, TEICHMANN S, MASSICOTTE M, KOPPENS F, LEVITOV LS, DE ABAJO FJG, BIEGERT J
  • 作者关键词:  
  • 出版物名称:   NATURE COMMUNICATIONS
  • ISSN:   2041-1723
  • 通讯作者地址:   Barcelona Inst Sci Technol
  • 被引频次:   1
  • DOI:   10.1038/s41467-018-03413-7
  • 出版年:   2018

▎ 摘  要

The speed of solid-state electronic devices, determined by the temporal dynamics of charge carriers, could potentially reach unprecedented petahertz frequencies through direct manipulation by optical fields, consisting in a million-fold increase from state-of-the-art technology. In graphene, charge carrier manipulation is facilitated by exceptionally strong coupling to optical fields, from which stems an important back-action of photoexcited carriers. Here we investigate the instantaneous response of graphene to ultrafast optical fields, elucidating the role of hot carriers on sub-100 fs timescales. The measured nonlinear response and its dependence on interaction time and field polarization reveal the back-action of hot carriers over timescales commensurate with the optical field. An intuitive picture is given for the carrier trajectories in response to the optical-field polarization state. We note that the peculiar interplay between optical fields and charge carriers in graphene may also apply to surface states in topological insulators with similar Dirac cone dispersion relations.