Tunable Terahertz Plasmons in Graphite Thin Films
Qiaoxia Xing, Chaoyu Song, Chong Wang, Yuangang Xie, Shenyang Huang, Fanjie Wang, Yuchen Lei, Xiang Yuan, Cheng Zhang, Lei Mu, Yuan Huang, Faxian Xiu, Hugen Yan
Abstract
Tunable terahertz plasmons are essential for reconfigurable photonics, which have been demonstrated in graphene through gating, though with relatively weak responses. Here we demonstrate strong terahertz plasmons in graphite thin films via infrared spectroscopy, with dramatic tunability by even a moderate temperature change or an in situ bias voltage. Meanwhile, through magnetoplasmon studies, we reveal that massive electrons and massless Dirac holes make comparable contributions to the plasmon response. Our study not only sets up a platform for further exploration of two-component plasmas, but also opens an avenue for terahertz modulation through electrical bias or all-optical means.