Metasurfaces constructed from metal nanostructures can operate as efficient coupling structures for incident optical beams to surface plasmons. On a semiconductor, metallic metasurfaces can act simultaneously as a device electrode while ensuring strong plasmon field overlap with the active region. Additionally, plasmon fields can be confined to subwavelength dimensions and significantly enhanced relative to the exciting field. These features are very attractive for nanoscale optoelectronic device applications, such as photodetectors and modulators, as the excitation of surface plasmons alters conventional trade-offs between responsivity and speed, or modulation and speed, respectively. We discuss recent progress on optoelectronic metasurfaces, particularly device demonstrations for sub-bandgap hot-carrier photodetection and high-speed modulation.
Pierre Berini, Pierre Berini,
"Optoelectronic metasurfaces: modulation and detection", Proc. SPIE 10530, Ultrafast Phenomena and Nanophotonics XXII, 105300B (22 February 2018); doi: 10.1117/12.2292649; https://doi.org/10.1117/12.2292649