Solar thermal absorber based on dielectric filled two-dimensional nickel grating

Abstract

In this paper, a solar thermal absorber based on a dielectric filled two-dimensional nickel grating is designed and numerically investigated for wide-angle and polarization-independent broadband absorption. The absorption of the proposed two-dimensional meta-surface absorber reaches nearly 100% in the whole visible region (400-800 nm). The physical mechanisms responsible for the high absorption including the impedance matching with the free space, the cavity resonances and the surface plasmonic resonances have been elucidated in detail. The strong resonances effectively trap the incident light in the nano-cavities and then dissipate it by the ohmic losses of the metal, giving rise to the high absorption of the proposed absorber. The meta-surface absorber may find applications in solar cells, photovoltaics, thermos-photovoltaics, thermal emitters, plasmonic sensors, and solar-energy harvesting.