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arXiv · 1805.10102

Wide-Band Nano-Imaging of Plasmon Dispersion and Hotspots in Quasi-Free-Standing Epitaxial Graphene

William S. Hart·Vishal Panchal·Christos Melios·Włodek Strupiński·Olga Kazakova·Chris C. Phillips
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Abstract

We report observation of graphene plasmon interference fringes across a wide spectral range using a scattering scanning near-field optical microscope (s-SNOM) that employs a widely tunable bank of quantum cascade lasers. We use plasmon interference to measure the dispersion curve of graphene plasmons over more than an order of magnitude of plasmon wavelength, from $\lambda_{sp}$ ~140 to ~1700 nm, and extract the electron Fermi energy of 298$\pm$4 meV for hydrogen-intercalated single layer epitaxial graphene on SiC. Furthermore, we demonstrate the appearance of wavelength tuneable graphene plasmon reflection "hotspots" at single-layer/bi-layer interfaces. This work demonstrates the capability of wide-band nano-imaging to precisely measure the electrical properties of graphene and spatially control plasmon reflection focusing.

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William S. Hart, Vishal Panchal, Christos Melios, Włodek Strupiński, Olga Kazakova, Chris C. Phillips. 2018-05-25. Wide-Band Nano-Imaging of Plasmon Dispersion and Hotspots in Quasi-Free-Standing Epitaxial Graphene. https://arxiv.org/abs/1805.10102

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