ABSTRACT
Thermal radiation management remains a challenge because of the incoherent and isotropic nature of electromagnetic waves. In this study, a multiband and angular-selective infrared emitter, consisting of a simple one-dimensional (1D) metal-dielectric-metal metamaterial, is demonstrated. Although this structure has been well-known as spectrally selective emitters, we analytically reveal that when the dielectric layer thickness is much smaller than the wavelength of interest (<1/10), directive emission at nearly equal to the grazing angles (>80°) can be obtained at multiple resonant wavelengths. Even though relatively broadband (8–14 μm) emission and angular shaping has been achieved through gradient ENZ structures in the far-IR range, the spectral control has been difficult. Recently, we have developed the directive emission with tunable spectral bands, as the emission peaks can be entirely characterized by geometrical parameters. This angular selective technology offers flexible control of thermal radiation and can be adjusted to specific applications.
