Frequency-Reconfigurable Wide-Angle Terahertz Absorbers Using Single- and Double-Layer Decussate Graphene Ribbon Arrays

Abstract

We propose and numerically demonstrate two novel terahertz absorbers made up of periodic single- and double-layer decussate graphene ribbon arrays. The simulated results show that the proposed absorbers have narrowband near-unity terahertz absorption with ultra-wide frequency reconfiguration and angular stability. By tuning the Fermi level of graphene ribbons, the over 90% absorbance peak frequency of the absorber with single-layer graphene structure can be flexibly adjusted from 6.85 to 9.85 THz for both the transverse magnetic (TM) and transverse electric (TE) polarizations. This absorber with single-layer graphene demonstrates excellent angular stability with the absorbance peaks of the reconfigurable absorption bands remaining over 99.8% in a wide angle of incidence ranging from 0 to 70°. The tuning frequency can be significantly enhanced by using the absorber with double-layer graphene structure from 5.50 to 11.28 THz and 5.62 to 10.65 THz, approaching two octaves under TM and TE polarizations, respectively. The absorbance peaks of the reconfigurable absorption band of this absorber for both polarizations maintain over 70%, even at a large angle of incidence up to 70°. Furthermore, an analytical fitting model is also proposed to accurately predict the absorbance peak frequencies for this variety of absorbers. Benefitting from these attractive properties, the proposed absorber may have great potential applications in tunable terahertz trapping, detecting, sensing, and various terahertz optoelectronic devices.

Metamaterial Absorbers: From Tunable Surface to Structural Transformation

“…In a work from Ye et al., a frequency‐reconfigurable narrowband MA has been proposed using double‐layer graphene ribbon with decussate arrays (Figure 6c) to significantly enhance the relative frequency tunability as well as the angular stability. [ 168 ] As displayed in Figure 6d,e, by applying bias voltage (0.2–0.9 V), the peak absorbance frequency of the graphene‐based MA was switched from 5.5 to 11.28 THz and from 5.62 to 10.65 THz at TM and TE polarization, respectively. Similar works and results have also been achieved by many other groups using graphene as the tuning counterparts.…”

“…As illustrated in Figure 6a,b, by controlling the V g , the E f of graphene can be tuned, resulting in the conveniently and dynamically tunable absorption performance of MAs. [74,104,163,167] Currently, both graphene films [107,163] and graphene patterns [73,162,164,[168][169][170] with single-layer or multilayer structures have been employed in tunable MAs designs. In a work from Ye et al, a frequencyreconfigurable narrowband MA has been proposed using double-layer graphene ribbon with decussate arrays (Figure 6c) to significantly enhance the relative frequency tunability as well as the angular stability.…”

Switchable and Dual-Tunable Multilayered Terahertz Absorber Based on Patterned Graphene and Vanadium Dioxide

“…Owing to its distinctive electromagnetic and optical properties, graphene is widely considered one of the most effective and promising metamaterials for designing tunable THz absorbers. Different broadband absorbers made of graphene with patterned disks and ribbons have been widely studied [7,[16][17][18][19]. Multilayer structure graphene-based absorbers and dual-band absorbers have also been proposed and analyzed [1,[20][21][22][23][24].…”

Tunable Terahertz Graphene-Based Absorber Design Method Based on a Circuit Model Approach

“…There are a number of studies that have used different geometric structures to excite SPPs in a somewhat different manner. For instance, structures including graphene stacks [8], hybrid-patterned graphene metasurfaces [10], decussate graphene ribbon arrays [11], elliptical geometries [12], multi-layer graphene [13], [14], composite graphene-metal microstructures [15], periodically sinusoidally-patterned graphene [16], metasurface [17], graphene sheet and patterned graphene [18], [19] have been reported. However, all the methods presented in most of these studies usually require full-wave simulations for designing and analyzing the structure.…”