Engineering super- and sub-radiant hybrid plasmons in a tunable graphene frame-heptamer metasurface

Controlling near-field electromagnetic interactions is central to tailoring optical responses in plasmonic systems. However, the static nature of conventional noble metal nanostructures limits their application in active photonic devices. In this work, we design and experimentally demonstrate a composite graphene metasurface, composed of an octagonal frame coupled to a central heptamer disk, that enables multidimensional and active control over hybrid plasmons. The observed rich spectral features originate from hybridization between the dipolar and higher-order modes of the frame and the collective resonances of the heptamer. We show that the polarization of incident light serves as an effective control parameter for engineering the radiative properties of these modes. By varying the polarization angle, specific resonances can be selectively driven into super-radiant states with enhanced radiation or sub-radiant states with suppressed emission. In parallel, electrostatic gating provides a second, independent tuning mechanism that enables wide, continuous, and robust spectral modulation, in excellent agreement with theoretical predictions. The combined use of structural design, polarization control, and electrical tuning transforms a static metasurface into a dynamically reconfigurable platform. This dual control over both resonance frequency and radiative coupling offers a comprehensive toolkit for on-demand manipulation of light–matter interactions, paving the way for advanced optical modulators, reconfigurable filters, and tunable sensing technologies.