Coupled metamaterial optical resonators for infrared emissivity spectrum modulation.

We study the absorptivity of coupled metamaterial resonators in the mid-infrared range. We consider resonators supporting either a bright mode or a dark mode, introducing an additional degree of freedom for spectral modulation relative to bright modes alone. In a dark-bright coupled resonator system, we demonstrate tunable spectral splitting by changing the separation between resonators. We show via coupled mode theory that resonator separation can be mapped to coupling constant. We further introduce a dark-dark coupled resonator system, which gives rise to an emissive bright mode only in the presence of inter-resonator coupling. The dark-dark system yields a broadband emissivity that decays to zero exponentially with resonator separation, providing a design method for strong thermal emissivity control.