Near-infrared tunable multiple broadband perfect absorber base on VO₂ semi-shell arrays photonic microstructure and gold reflector

We proposed a metamaterial absorber which is aimed to achieve a multiple broadband absorption and tunable absorption peak in the near-infrared region. The absorber is based on VO₂ semi-shell coated on the top of silica nano-particle array supported on the gold-reflective layer. Measured results show that the absorber has the multiple broadband with the absorption magnitudes more than 95% in the near infrared region. The absorption peaks can be tuned through the VO₂ phase transition from metallic phase to insulator phase in the short wavelength (before λ=1500 nm), when VO₂ is at the metallic state, an absorption band appears in the long wavelength (after λ=1500 nm). The simulation results closely match those of measured. The absorption intensity becomes stronger and absorption peaks have red shift with the increase of thickness of VO₂ semi-shell. Thus, this designed tunable absorption intensity and position absorber based on VO₂ can be a good choice for enhancing the performance of multiple band, this would be beneficial to the field of photo detectors, sensor and solar cell.