Temperature controlled perfect absorber based on metal-superconductor-metal square array

The optical properties of a single-band near-perfect absorber are studied numerically by using a finite element method in conjunction with a two-fluid model. Based on a metal-superconductor-metal (MSM) scheme, the proposed structure comprises a lossless superconducting layer sandwiched by a silver square array and ground silver plane. The simulation results clearly show that near-perfect absorption band can be realized and promptly tuned from green light to red light by the temperature of the system. The designed MSM absorber also presents the characteristics of polarization insensitivity and wide-angle incidence up to 50 degree. This prompt manipulation of the near-perfect absorption band makes this MSM absorber a great potential candidate when designing an in-situ absorption band selector in the visible light wavelength regime.