| Popis: |
Metasurfaces composed of sub-wavelength fabricated structures have shown potential for exceptional control of light. In this talk I will show that by incorporating graphene into the structure of a metasurface, devices can be fabricated that have electrostatically tunable emissivities and reflectivities. It will be shown that the thermal emission from a metasurface can be widely varied in terms of spectral shape, polarization and intensity, and that thermally emitting devices with Mhz response times can be created in this way. By carefully controlling the DC permittivity, index of refraction, and thickness of the supporting substrate, it will also be demonstrated that the efficiency and optical response of these devices can be dramatically altered. Notably, the coupling of graphene plasmons with substrate phonons is found to play an important role in the spectral response of these metasurfaces, and the use of high-k dielectrics can increase maximum efficiency and range of control attainable in graphene metasurfaces. |
