Perfect metamaterial absorber for solar energy utilization

A polarization insensitive, broadband and wide-angle perfect metamaterial absorber for nearly full solar spectrum harvesting is designed and studied. The structure is a periodic dielectric square array coated with an iron film separated from a bottom iron film by a silica planar and a phase change material cavity. Above 93% absorbance over the spectral range of 400–2000 nm along with 98% average absorption are achieved. The underlying physical mechanism is interpreted by illustrating the electric field intensity distributions at several resonant peaks. In addition, such high and wideband absorption properties remain excellent in a very wide incident angle ranges and the designed absorber possesses large fabrication tolerance, both of which are very attractive for practical application. Furthermore, the absorption spectra are commendably consistent with the AM1.5 spectrum, and the integrated absorption for nearly full solar spectrum is robust against the angle of incidence. These results indicate that the proposed scheme can be applied in solar energy harvesting as well as broadband thermal emission.