Graphene-based Fabry-Pérot-integrated THz photodetector with ultra-high responsivity

We report a sub-THz hBN-encapsulated single layer graphene THz detector with a large responsivity and phase sensitivity. The large response, centered at 89 GHz, is due to an engineered Fabry-Pérot cavity allowing us to reach up to 0.3 A/W at the cavity mode, obtained in a passive, bias-free device. This suggests a near-unity THz absorption in the graphene channel via multiple wave reflections, demonstrating that this photonic strategy enables efficient THz light coupling in graphene-based photodetectors that simultaneously act as interferometers.