Design of a Penta-Band Graphene-Based Terahertz Metamaterial Absorber with Fine Sensing Performance

Abstract

This paper presents a new theoretical proposal for a surface plasmon resonance (SPR) terahertz metamaterial absorber with five narrow absorption peaks. The overall structure comprises a sandwich stack consisting of a gold bottom layer, a silica medium, and a single-layer patterned graphene array on top. COMSOL simulation represents that the five absorption peaks under TE polarization are at fI = 1.99 THz (95.82%), fⅡ = 6.00 THz (98.47%), fⅢ = 7.37 THz (98.72%), fⅣ = 8.47 THz (99.87%), and fV = 9.38 THz (97.20%), respectively, which is almost consistent with the absorption performance under TM polarization. In contrast to noble metal absorbers, its absorption rates and resonance frequencies can be dynamically regulated by controlling the Fermi level and relaxation time of graphene. In addition, the device can maintain high absorptivity at 0~50° in TE polarization and 0~40° in TM polarization. The maximum refractive index sensitivity can reach SV = 1.75 THz/RIU, and the maximum figure of merit (FOM) can reach FOMV = 12.774 RIU−1. In conclusion, our design has the properties of dynamic tunability, polarization independence, wide-incident-angle absorption, and fine refractive index sensitivity. We believe that the device has potential applications in photodetectors, active optoelectronic devices, sensors, and other related fields.

Terahertz absorber based on vanadium dioxide with high sensitivity and switching capability between ultra-wideband and ultra-narrowband

“…Moreover, the absorption device has a RB of 82.03% in the frequency band of 3.02–7.22 THz for ultra-high absorption with more than 90% absorption. While when VO 2 is in the insulating state ( σ ( ω ) ≤ 820 S m −1 and the temperature rise is less than 60 °C), 40 the device is in the ultra-narrow band perfect absorption mode, where we only discuss the absorption at 7–8 THz, due to the fact that at this point, the absorption is close to 0 at both 2–7 THz. Fig.…”

Regulating Photocurrent Polarity Reversal Point in α-Ga2O3 Nanorod Arrays for Combinational Logic Circuit Applications

“…Furthermore, if a control method for the photovoltaic current polarity inversion point in the PEPS effect is found, it can improve the utilization efficiency of the device’s PEPS effect and enable it to be applied in more diverse scenarios. Two-dimensional materials (2DMs) have significant potential to enhance sensor performance and manipulate the optoelectronic properties of semiconductor materials due to their unique and rich physical and chemical characteristics, including ultrathin geometry, high surface atomic ratio, semiconductor, superconductive, magnetic, charge density wave, etc. , Recent studies of two-dimensional materials have focused on metamaterial absorber. − Among many 2DMs, Ti 3 C 2 T x as functional modification materials has extensive market prospects due to its rich surface functional groups, high Young’s modulus, large interlayer spacing, conductive gold properties, large specific surface area, low cost, and ease of preparation . In addition, Ti 3 C 2 T x has strong redox properties, which helps to increase the chemical reaction activity of the charge carriers and accelerate effective charge separation and directed charge transport. − Consequently, Ti 3 C 2 T x can serve as an excellent material for modifying PEC devices and is a critical approach to solving key issues in the development of current semiconductor optoelectronic devices.…”

Design of metamaterial perfect absorbers in the long-wave infrared region

“…Metamaterial absorbers in the infrared band have been widely studied, for example, Liu et al designed a mid-infrared cross-shaped metamaterial absorber that achieved 97% absorption at 6 μm, 11 and Li et al proposed a single-layer gold disc metamaterial absorber with 97% absorption at 13 μm wavelength. 12 Monolayer metals (high dielectric constant) can excite a sharp localized plasmon resonance, effectively localizing the energy on the metal surface and achieving perfect absorption, 13–16 but the limitation to metal materials and shapes and the single resonant frequency are not conducive to a wide range of absorber applications. For dielectric nanostructures, the absorption bandwidth is not wide due to its less lossy nature, and it is more dependent on the resonant structural design to extend the absorption bandwidth.…”