20 March 2023 Broadband terahertz absorber based on the coupling between Au and graphene
Aiyu Li, Yijun Cai, Dong Sun
Author Affiliations +
Abstract

A simply designed broadband meta-absorber (MA) that works in terahertz (THz) band is proposed and investigated. The reflector substrate of the MA is composed of nickel. The middle layer of this structure is made of dielectric Al2O3, which serves as a dielectric layer between the nickel and the metasurface layer. The metasurface layer comprises a graphene ring with a disk-like Au in the center. The wideband absorption mechanism benefits from the hybridized surface plasmonic modes caused by the coupling between the Au disk and the graphene ring. Besides, with the adhesion of the top Au metal disk, Fabry-Perot cavities formed by the top Au and the bottom metal produce the continuous cavity resonant modes also to enhance surface hybridization plasmons. Because the proposed broadband MA is symmetrical, it is insensitive to polarization and has a good bearing angle of 0 deg to 70 deg. The results of our study may inspire specific applications of wave modulation, including THz imaging, detecting, modulation, and sensing.

© 2023 Society of Photo-Optical Instrumentation Engineers (SPIE)
Aiyu Li, Yijun Cai, and Dong Sun "Broadband terahertz absorber based on the coupling between Au and graphene," Optical Engineering 62(3), 037106 (20 March 2023). https://doi.org/10.1117/1.OE.62.3.037106
Received: 1 November 2022; Accepted: 27 February 2023; Published: 20 March 2023
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KEYWORDS
Graphene

Absorption

Gold

Terahertz radiation

Metals

Plasmonics

Dielectrics

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