Triple broadband polarization-insensitive tunable terahertz metamaterial absorber on a hybrid graphene-gold pattern

Abstract

In this paper, we propose a triple broadband metamaterial absorber with a composite hybrid structure of graphene and gold patch embedded in silica. Based on the analogy of a transmission line, this technique may yield polarization-insensitive triple-broadband terahertz absorption with adjustable active control by combining the benefits of gold and graphene. Simulation results indicate that when graphene’s electrochemical potential (Fermi energy) is adjusted to 0.9 eV, the absorber exhibits three broadband absorptions of more than 90% in the frequency ranges of (1.1-2.72) THz, (5.39-6.47) THz, and (9.25-10.97) THz, with a total bandwidth of 4.42 THz for the TE waves. The bandwidth for the TM waves is around 4.29 THz with absorbance greater than 90% in the frequency ranges of (1.14–2.64) THz, (5.51–5.5) THz, and (9.18–10.98) THz. Moreover, the proposed metamaterial absorber is polarization insensitive for both the TE and TM waves and maintains a strong absorption efficacy for both the TE and TM waves at incident angles of less than 40°. Therefore, a single layer of hybrid graphene-gold patch makes the proposed structure extremely simpler and provides triple broadband absorption with a much higher bandwidth with polarization insensitive characteristics, hence, could be used in soaking electromagnetic waves, modulators, detecting signals, tunable filtering, and other broadband devices.