Structure-insensitive switchable terahertz broadband metamaterial absorbers

A nearly structural-insensitive switchable broadband terahertz metamaterial absorber is proposed, which consists of several gold rods and a vanadium dioxide (VO2) ground plane separated by a dielectric spacer. By controlling the temperature of VO2, state of the absorber can be switched from "on" to "off" in the frequency range of 1.116-1.564 THz. The physical mechanism of the absorber is given based on the wave-interference theory and field distributions. Interestingly, the proposed absorber shows a similar performance for random arrangements of a given number of rods on the top layer, which could greatly reduce the requirement of fabrication accuracy.