Composite Metamaterials for THz Perfect Absorption

Abstract

The design, characterization, and experimental demonstrations are presented for triple‐band, near‐perfect, composite metamaterials that absorb in the terahertz regime. Three absorption peaks are observed at 0.537 THz, 0.948 THz, and 1.59 THz with the respective absorption coefficients of 0.957, 0.988, and 0.96. The effect of spacer thickness on absorption is analyzed with interference theory, and the conditions for unity absorption are obtained via comparison of amplitude and phase. The effect of the length ( l ) of four outer parts of Jerusalem cross on the absorption is analyzed via transmission line theory. Furthermore, the absorption effects of capacitance and inductance caused by the changing l are examined. The calculated multi‐band transmission line model corresponded well to simulations. The effect of the outside length on the absorber performance is further explained by electric field distributions, which is experimentally confirmed. Overall, the consistent conclusions provide design guidance for metamaterial absorbers, or the realization of tunable absorbers, and provide a further understanding of the mechanisms.