For the high-emissivity states of the metasurface, we utilize the high index and lossy properties of EB to introduce two absorption mechanisms: asymmetric Fabry-Pérot (AFP) cavity and gap surface plasmon (GSP) resonance, in the long-wavelength region. In Figure , the reflectance spectra at both emissivity states are plotted with periodic meta-atoms with parameter (hCP, D) = (1, 2.8) μm. The results demonstrate a prominent broadband reflectance contrast of two emissivity states between 8 to 22 μm from the combined effect from chemical absorption, AFP, and GSP resonance. The absorption peaks at 10 μm and 18 μm corresponds to AFP and GSP respectively. In Figure , we recorded the simulated reflectance spectra with respect to disk diameter (D) and the absorption peak position of both resonances, which clearly depicts the independence and the dependence of AFP and GSP, respectively.