Multi-Band Terahertz Absorber at 0.1-1 THz Frequency Based on Ultra-Thin Metamaterial

In this letter, we design a terahertz (THz) multi-band absorber comprised of four square open/closed loops and a ring wall resonant metamaterial with a high absorption rate for TE and TM polarization. Based on resonant response of metamaterial, five different sizes of the metal rings could tune five absorption peaks to produce five-band absorbing performance in the frequency ranging from 0.1 to 1 THz. By comparing the absorber consisting of independent ring with multiple rings, the multi-band absorption could be demonstrated by increasing the number of metal rings. The simulation results are indicated that the multiband absorbing of the THz absorber is independent of incident angle within a wide range. The design method of the absorber presented can not only provide a theoretical tool to perform diversity absorbing with multiple band and multi-absorption azimuth in terahertz communications, but also has potential for applications in THz imagers, detectors, sensors, and emitters.