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In this work, we report an intensive theoretical study on the achieving of multiple ultra-sharp and near-unity absorption in a cavity enabled graphene absorber. The plasmonic-induced magnetic resonance, i.e., magnetic plasmon is excited and localized efficiently via the one-dimensional metallic oblique slit array. The slit concentrates highly for the plasmonic field in a limited spatial cavity and simultaneously intensifies the graphene-field coupling, which leads to the emergency of the multi-band high-quality (Q) factor (190) ultra-sharp perfect absorption. Although the graphene-slit interaction area is just 17.7% of the structural size, the maximal absorption efficiency reaches 99.8%. In the near-infrared range, a large spectral intensity change of 82% is achieved when the graphene's Fermi energy is manipulated by a slight value of 0.03 eV, which directly introduces a viewable switching process between the operation "on" and "off" states. The optical sensing sensitivity is also up to 1276 nm/RIU and the FOM factor reaches 106. During the application for temperature detecting, the resolution limit can be as down as 3 × 10−3 °C (K), suggesting a desirable temperature detector. Moreover, polarization-adjustable and angle-insensitive properties for the plasmonic graphene absorber could further promote enormous applications for the active optoelectronic devices. Image 1 • A high- Q plasmonic graphene absorber is demonstrated via an oblique air slit array in the metal substrate. • A viewable switching process between the operation "on" and "off" states is demonstrated. • High-performance optical sensor and temperature detector are obtained via this graphene absorber. [ABSTRACT FROM AUTHOR]

Electrically modulating and switching the light absorption properties of monolayer graphene in near-infrared region has potentials in optoelectronic devices (e.g., photodetectors) and optical communication systems (e.g., modulators). In this work, we demonstrate numerically a broadband near-infrared absorption enhancement of monolayer graphene, due to the magnetic dipole resonance in metamaterials. The broadband light absorption in monolayer graphene can be largely modulated to realize an electrically switchable effect, via bias voltage for the interband transition of graphene to be near the magnetic dipole resonance. The absorption modulation depth is able to vary quickly from almost zero to nearly 100% in a very narrow wavelength range around the interband transition. Electrically modulating and switching the light absorption properties of monolayer graphene in near-infrared region has potentials in optoelectronic devices (e.g., photodetectors) and optical communication systems (e.g., modulators). In this work, we firstly demonstrate numerically a broadband near-infrared absorption enhancement of monolayer graphene, due to the magnetic dipole resonance in metamaterials. Then, we show that the broadband light absorption in monolayer graphene can be largely modulated to realize an electrically switchable effect, via bias voltage for the interband transition of graphene to be near the magnetic dipole resonance. The absorption modulation depth is able to vary quickly from almost zero to nearly 100% in a very narrow wavelength range around the interband transition. Image 107 [ABSTRACT FROM AUTHOR]

Abstract Graphene nano-structures have been widely studied as means of creating resonant absorption and index tunability by graphene plasmons. However, only the relatively low modulation efficiency and qualitatively adjusting methods have been achieved. Here we demonstrate a graphene plasmonic perfect absorber (GPPA) platform, which can provide perfect absorption in the multispectral range. Moreover, artificially tunable absorption response for the GPPA can be achieved via the external stimuli by the polarization state of the illumination. Efficient quantitative modulation on the spectral absorption is achieved since it can be predicted by the Malus law. Importantly, near-perfect modulation depth of 99.9% (∼100%) and the ultra-high relatively modulation intensity (MI) up to 3590 are achieved for the graphene plasmon switch via an electrical-control treatment. Furthermore, the positions of the absorption peaks are with nearly perfect linear relationship to that of the Fermi energy for the GPPA, suggesting an interesting way to quantitatively shift the resonant absorption wavelength. These features confirm the simultaneous support of optical and electrical manipulation for the quantitatively artificial control on the resonant behaviors for the GPPA. The findings could pave new insights on the light modulators by the plasmonic graphene and hold potential applications on the artificially precise-adjusting switch and devices. Graphical abstract A graphene plasmonic perfect absorber (GPPA) platform with narrowband perfect absorption in the multispectral range is proposed. Artificially tunable absorption response for the GPPA can be achieved via the external stimuli by the polarization state of the illumination. Near-perfect modulation depth (MD) of ∼100% and the ultra-high relatively modulation intensity (MI) up to 3590 are achieved for the graphene plasmon switch via an electrical-control treatment. The positions of the absorption peaks can be quantitatively shifted by the Fermi energy for the GPPA. Image 1 [ABSTRACT FROM AUTHOR]