(color online) Emissivity spectra of the grating at different filling factors with (a), (b) h = 0.3 μm, (c), (d) h = 0.6 μm, (e), (f) h = 1.0 μm, and (g), (h) h = 1.6 μm. Resonance A represents the peak that is narrow and fixed at 4 μm, while resonance B is wide and varied (same as Fig. 4). The details of the emission spectra at around 4 μm are demonstrated in the left column.