Tunable broadband metamaterial absorber with voltage and temperature modulation

Abstract

It is well known that VO2 has temperature-controllable phase transition properties, and that graphene surface conductivity's can be changed by applying a gate voltage to control the Fermi energy level. On the basis of temperature and voltage controllability, we numerically simulate a broad-band mid-infrared absorber. The metamaterial absorber (MA) operates in the mid-infrared band of 7∼30 μm, and when VO2 is in the metallic state, the absorption bandwidth can reach 9 μm and the average absorption can reach 98%. The absorption bandwidth is temperature-adjustable. By maintaining graphene's Fermi energy level (EF) at 0.4 EF. When VO2 transitions between insulating and metallic states, MA can achieve mid-infrared narrowband-broadband interconversion. When VO2 is in the insulating state, tuning the EF of graphene, MA can achieve single-peak and double-peak absorption in mid-infrared wavelength, respectively. When VO2 is in the metallic state, the EF can be used to dynamically modulate the absorption bandwidth. The MA reveals its thermal switching properties. This research is expected to have promising future applications in the fields of multiparameter tunable optical devices, temperature sensing, infrared detection, etc.