Study on vanadium dioxide based terahertz metamaterials with switchable functions from five-band absorption to triple-band plasmon-induced transparency

A bifunctional switchable terahertz metamaterial utilizing vanadium dioxide (VO2) able to dynamically convert from multiband absorption to multiband plasmon-induced transparency (PIT) is designed, which is consisted of four different-sized metallic split rings placed on a dielectric slab backed by a continuous VO2 film. Based on unique insulator-metal phase transition properties of VO2, the present functions of designed structural could be realized by changing the temperature of VO2. When the VO2 is in the conducting phase, it possesses five discrete absorption peaks with the frequencies of 1.30 THz, 1.48 Hz, 2.07 THz, 2.46 THz and 2.72 THz with average absorbance greater than 98.0%. When the VO2 is in the insulating phase, it exhibits three obvious PIT peaks, the transmittances of them are 79.5%, 95.3% and 99.7% at the frequencies of 1.57 THz, 1.75 THz and 2.09 THz, respectively. Effects of geometric parameters on absorption and transparency are investigated. Results revealed that the dimension changes of surface patterned arrays show an important role in controlling resonance responses of absorption and transparency behavior. The switchable VO2-based metamaterial could have great potential applications in the fields of smart absorption, terahertz optical switches, filters, and slow-light devices.