Metasurface cutoff perfect absorber in a solar energy wavelength band

We report a metasurface cutoff perfect absorber (MCPA) in the solar energy wavelength band based on the double Mie resonances generated from the silicon and gallium arsenide nanoring arrays grown on the Al layer in the solar energy wavelengths. A high average absorption of 0.910 in the absorption band and almost eliminated absorption in the nonabsorption band are realized within only 120 nm thick structures. The MCPA is of a sharp cutoff between the absorption and nonabsorption band, whose extinction ratio, extinction difference, and cutoff slope are 9.4 dB, 0.8, and 0.0019n m ^-1, respectively. The proposed MCPA suggests an efficient way to design a solar thermal absorber, which is of great importance in renewable energy, such as for solar thermal applications.