A Narrow Dual-Band Monolayer Unpatterned Graphene-Based Perfect Absorber with Critical Coupling in the Near Infrared

Abstract

The combination of critical coupling and coupled mode theory in this study elevated the absorption performance of a graphene-based absorber in the near-infrared band, achieving perfect absorption in the double bands (98.96% and 98.22%), owing to the guided mode resonance (the coupling of the leak mode and guided mode under the condition of phase matching, which revealed 100% transmission or reflection efficiency in the wavelet band), and a third high-efficiency absorption (91.34%) emerged. During the evaluation of the single-structure, cross-circle-shaped absorber via simulation and theoretical analysis, the cross-circle shaped absorber assumed a conspicuous preponderance through exploring the correlation between absorption and tunable parameters (period, geometric measure, and incident angle of the cross-circle absorber), and by briefly analyzing the quality factors and universal applicability. Hence, the cross-circle resonance structure provides novel potential for the design of a dual-band unpatterned graphene perfect absorber in the near-infrared band, and possesses practical application significance in photoelectric detectors, modulators, optical switching, and numerous other photoelectric devices.

A Tunable Triple-Band Near-Infrared Metamaterial Absorber Based on Au Nano-Cuboids Array

“…Local surface plasmon resonance is an important branch of the surface plasmon field. In particular, the local surface plasmon resonance (LSPR) of Au nanoparticles (NPs) has received extensive attention for many years due to its unique optical properties [16][17][18]. Under the action of incident light, the collective oscillation of Au free electrons can enhance the local electromagnetic field on their surface [19].…”

Tunable Mid-Infrared Graphene Plasmonic Cross-Shaped Resonator for Demultiplexing Application

“…In practice, graphene has strong confinement of lightwaves, long propagation length, and low loss making it superior to metals [21][22][23]. Because of the significant advantages of graphene, many graphene based structures-such as filters [24,25], demultiplexers [26,27], modulators [28,29], couplers [30,31], absorbers [32,33], and solar cells [34]-are designed and analyzed. Fabrication of graphene-based devices in MIR region was recently reported in [35,36].…”

High Quality Factor, High Sensitivity Metamaterial Graphene—Perfect Absorber Based on Critical Coupling Theory and Impedance Matching

“…Graphene has extremely high carrier mobility [24,25] and full spectral response to light in the ultraviolet to terahertz band, and ultra-fast response to light, making it a perfect optoelectronic device material. The application of levitated monolayer graphene in photovoltaic field is limited to some extent because its absorption efficiency of ordinary incident light is merely 2.3% [26]. All in all, resonance effect is the key method for enhancing material absorption or emission [27,28].…”