Tunable Fully Absorbing Metasurfaces for Efficient THz Detection

Terahertz photoconductive antennas with a nanostructured active region have been actively investigated recently with a goal to achieve high efficiency THz detectors and emitters. Here we provide a novel design of perfectly-absorbing photoconductive region without plasmonic elements using a metasurface, and provide a systematic method by which the metasurface can be designed to work optimally for varying optical gate frequencies across the GaAs band-gap. This paves the way to using metasurface devices for THz detection and other applications in a wide range of laser systems operating at different wavelengths or with different photoconductive materials.