Enhancement of a tunable single-band metamaterial absorber based on bright–bright modes coupling effect in terahertz range

Abstract

In this paper, a Dirac semimetal-based tunable single-band metamaterial absorber is revealed in the terahertz band, which obtains an absorption peak with 92% amplitude at the resonance frequency based on the bright–bright modes coupling effect. This absorption peak is enhanced to 96% and shifted to lower frequencies when the structural parameter V is reduced to 12 μm. On the other hand, the absorption peak is enhanced to 95% and shifted to higher frequencies when the structural parameter H is reduced to 12 μm. New absorption bands are achieved when structural parameters V = 10 μm or H = 10 μm. This absorption peak can be shifted from 3.42 to 4.16 THz based on increasing the Fermi energy from 55 to 75 meV. Moreover, this absorption peak can also be modulated increased the strength of parallel or vertical magnetic fields, which leads to the resonance frequency is shifted to higher and lower resonance frequencies, respectively. This proposed tunable single-band metamaterial absorber shows the potential applications in optical sensing.