Design and Experiment of a Tunable Terahertz Absorber Based on Vanadium Dioxide Metamaterial

In this paper, a tunable terahertz absorber is demonstrated and experimentally verified, which is composed of a patterned vanadium dioxide (VO 2 ) film and a metal reflector layer, separated by a quartz dielectric medium. A tunable absorptivity property of the absorber, revealed at frequencies of 0.5 THz and 0.85 THz, can be flexibly designed by manipulating the conductivity of VO 2 . The simulated results show that, the absorptivity of 99.9% and 3.1 % can be achieved when the conductivity of VO 2 film at 30000 S/m and 100 S/m, respectively. A sample of the designed absorber prototype is manufactured under a micro-fabrication process and measured through a terahertz time-domain spectral system in free-space. The conductivity of VO 2 is manipulated by a thermostatic table, and the measured results verify the tunable absorptivity property of the absorber. This proposed prototype is an effective manner for tunable terahertz metamaterial absorbers, which has potential applications in the fields of sensor, military stealth, and energy harvesting.