Dynamically Tunable Perfect Absorbers Utilizing Hexagonal Aluminum Nano-Disk Array Cooperated with Vanadium Dioxide

A tunable perfect absorber composed of hexagonal-arranged aluminum nano-disk array embedded in the vanadium dioxide (VO_2) film is proposed. The aim is to achieve the tunability of resonance absorption peak in the visible and near-infrared regimes. Numerical results reveal that the absorption peak achieves a large tunability of 76.6% while VO_2 undergoes a structural transition from insulator phase to metallic phase. By optimizing the structural parameters, an average absorption of 95% is achieved from 1242 to 1815 nm at the metallic phase state. In addition, the near unity absorption can be fulfilled in a wide range of incident angle (0^\circ–60^\circ) and under all polarization conditions. The method and results presented here would be beneficial for the design of active optoelectronic devices.