An ultra-thin isotropic metamaterial thermal radiator

We design an ultra-thin infrared metamaterial thermal radiator which has nearly isotropic emission pattern for a wide range of angles. Our design is achieved by overlapping both the electric and magnetic resonances in the spectral domain and is insensitive to both TE and TM polarizations. The thermal emission of the metamaterial is nearly isotropic in which the deviation in the angular emissivity is within 10% up to an angle of 75 degrees at the resonating wavelength of 2.86 mu m. Moreover, our metamaterial can be easily scaled to have different resonating wavelengths for efficient radiative cooling or thermal emission at different temperatures. Copyright (C) EPLA, 2011