Broadband terahertz tunable multi-film absorber based on phase-change material

Abstract

Based on the impedance matching method, we have numerically demonstrated a broadband tunable multilayer structure in a terahertz (THz) regime. The switchable functional characteristics of the absorber can be achieved by utilizing the phase transition property of vanadium dioxide ( V O 2 ). When V O 2 is in the metallic state, the designed device behaves as a broadband absorber with an absorbance greater than 90% under normal incident from a 4.5 to 10 THz range. When V O 2 is in the insulating state, the absorption in this band is down to near 0%. Moreover, this high absorption band shows a good polarization insensitive property and can be maintained over a range of incident angles up to 45°. Our proposed device exhibits the merits of wideband reconfigure absorbance in THz, and the absorber can be easily fabricated without involving any lithographic process, both of which are very attractive to potential THz applications such as sensing, camouflaging, and modulation of THz waves.