Hybrid-Mode-Enhanced Terahertz Rectification in Multilayer Graphene Devices

High Resolution Image Download MS PowerPoint Slide We present a hybrid plasmonic-cavity approach for electrical terahertz detection based on asymmetrically dual-gated multilayer graphene with a geometric cavity formed by the substrate wafer providing additional field enhancement. The measured photocurrent response exhibits a dominant resonance near 150 GHz, with additional satellite features from hybridization of confined plasmonic and geometric modes. While the geometry defines the resonant modes, the rectification mechanism is governed by the electronic properties of the multilayer graphene, via resistive self-mixing driven by local electromagnetic fields and photothermal effects induced by thermal gradients. By independently tuning the Fermi levels via the top and back gates, we control both the coupling strength and the spectral weight of these hybrid modes. A compact model that incorporates a single effective coupling parameter reproduces the essential features of the measured spectra. These results demonstrate the potential of engineered hybrid resonances for graphene-based THz detection in multilayer systems.