scholarly journals Numerical Study of Angle-Insensitive and Tunable Dual-Band THz Absorber Using Periodic Cross-Shaped Graphene Arrays

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2063 ◽  
Author(s):  
Tian Sang ◽  
Jian Gao ◽  
La Wang ◽  
Honglong Qi ◽  
Xin Yin ◽  
...  
Keyword(s):  
Transverse Electric ◽  
Numerical Study ◽  
Transverse Magnetic ◽  
Dual Band ◽  
Absorption Enhancement ◽  
Cavity Model ◽  
Absorption Bands ◽  
Fabry Perot ◽  
Band Absorption ◽  
The Cross

A dual-band terahertz (THz) absorber using the periodic cross-shaped graphene arrays is presented. It is shown that the dual-band light absorption enhancement of graphene results from the edge graphene plasmon (EGP) resonance, and the locations of the two absorption peaks can be precisely estimated by using the Fabry-Pérot (F-P) cavity model. Slight residual reflection remains at the two absorption peaks because the input impedance of the cross-arm cannot be perfectly matched with the free space impedance. In addition, the locations of the two absorption bands can be simultaneously tuned by changing the Fermi level of graphene, and they can be independently tuned by changing the width or the length of the cross-arm of graphene. Excellent angle-insensitivity dual-band absorption enhancement of graphene can be maintained for both the transverse electric (TE) and transverse magnetic (TM) polarizations.

scholarly journals Dual-Band Light Absorption Enhancement in Hyperbolic Rectangular Array

2019 ◽  
Vol 9 (10) ◽  
pp. 2011 ◽  
Author(s):  
Honglong Qi ◽  
Tian Sang ◽  
La Wang ◽  
Xin Yin ◽  
Jicheng Wang ◽  
...  
Keyword(s):  
Light Absorption ◽  
Effective Medium Theory ◽  
Impedance Matching ◽  
Dual Band ◽  
Absorption Enhancement ◽  
Absorption Bands ◽  
Absorption Properties ◽  
Rectangular Array ◽  
Medium Theory ◽  
Band Absorption

The effect of dual-band light absorption enhancement in a hyperbolic rectangular array (HRA) is presented. The enhanced light absorption of the HRA results from the propagating surface plasmon (PSP) resonance, and a dual-band absorption with low and flat sideband level can be realized. The impedance theory is used to evaluate the absorption properties of the HRA, and shows that the input impedances of the HRA varied abruptly around the absorption bands to meet the impedance matching. The absorption spectra of the HRA can be estimated using the effective medium theory (EMT), and its accuracy can be improved as the number of film stacks is increased. The dual-band absorptions of the HRA are very robust to the variations of the width and the number of film stack. Potential application in refractive index sensing can be achieved by utilizing the two absorption bands.

Single-peak-regulation and wide-angle dual-band metamaterial absorber based on hollow-cross and solid-cross resonators

2020 ◽  
Vol 91 (3) ◽  
pp. 30901
Author(s):  
Yibo Tang ◽  
Longhui He ◽  
Jianming Xu ◽  
Hailang He ◽  
Yuhan Li ◽  
...  
Keyword(s):  
Transverse Electric ◽  
Surface Current ◽  
Dielectric Substrate ◽  
Transverse Magnetic ◽  
Metamaterial Absorber ◽  
Absorption Peak ◽  
Dual Band ◽  
Single Peak ◽  
Wide Angle ◽  
Surface Current Density

A dual-band microwave metamaterial absorber with single-peak regulation and wide-angle absorption has been proposed and illustrated. The designed metamaterial absorber is consisted of hollow-cross resonators, solid-cross resonators, dielectric substrate and metallic background plane. Strong absorption peak coefficients of 99.92% and 99.55% are achieved at 8.42 and 11.31 GHz, respectively, which is basically consistent with the experimental results. Surface current density and changing material properties are employed to illustrate the absorptive mechanism. More importantly, the proposed dual-band metamaterial absorber has the adjustable property of single absorption peak and could operate well at wide incidence angles for both transverse electric (TE) and transverse magnetic (TM) waves. Research results could provide and enrich instructive guidances for realizing a single-peak-regulation and wide-angle dual-band metamaterial absorber.

scholarly journals Investigation on the Optical Dual-band Absorption Enhancement for Graphene Photodetector

2021 ◽  
pp. 104747
Author(s):  
Haixia Liu ◽  
Shashi Zhang ◽  
Hao Ding ◽  
Wei Sun ◽  
Lichen Sun
Keyword(s):  
Dual Band ◽  
Absorption Enhancement ◽  
Band Absorption

scholarly journals Quad-Band Plasmonic Perfect Absorber for Visible Light with a Patchwork of Silicon Nanorod Resonators

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1954 ◽  
Author(s):  
Can Cao ◽  
Yongzhi Cheng
Keyword(s):  
Visible Light ◽  
Transverse Electric ◽  
Transverse Magnetic ◽  
Localized Surface Plasmon ◽  
Perfect Absorber ◽  
Absorption Properties ◽  
Perfect Absorption ◽  
Potential Applications ◽  
Polarization Insensitive ◽  
Band Absorption

In this paper, a plasmonic perfect absorber (PPA) based on a silicon nanorod resonator (SNRR) for visible light is proposed and investigated numerically. The proposed PPA is only a two-layer nanostructure consisting of a SNRR periodic array and metal substrate. The perfect absorption mainly originates from excitation of the localized surface plasmon resonance (LSPR) mode in the SNRR structure. The absorption properties of this design can be adjusted by varying the radius (r) and height (h) of the SNRR structure. What is more, the stronger quad-band absorption can be achieved by combing four different radius of the SNRR in one period as a super unit-cell. Numerical simulation indicates that the designed quad-band PPA can achieve the absorbance of 99.99%, 99.8%, 99.8%, and 92.2% at 433.5 THz, 456 THz, 482 THz, and 504.5 THz, respectively. Further simulations show that the proposed PPA is polarization-insensitive for both transverse electric (TE) and transverse magnetic (TM) modes. The proposed PPA can be a desirable candidate for some potential applications in detecting, sensing, and visible spectroscopy.

Multispectral Plasmon of Anisotropic Core-shell Gold Nanorods@SiO2: Dual-band Absorption Enhancement with Coupling Dye Molecules

2018 ◽  
Vol 34 (5) ◽  
pp. 772-780 ◽  
Author(s):  
Yuping Che ◽  
Yang Wang ◽  
Tingting You ◽  
Huaiqiu Chang ◽  
Penggang Yin ◽  
...  
Keyword(s):  
Gold Nanorods ◽  
Dual Band ◽  
Absorption Enhancement ◽  
Core Shell ◽  
Dye Molecules ◽  
Band Absorption

scholarly journals A Fabry–Perot interferometer-based camera for two-dimensional mapping of SO<sub>2</sub> distributions

2014 ◽  
Vol 7 (11) ◽  
pp. 3705-3715 ◽  
Author(s):  
J. Kuhn ◽  
N. Bobrowski ◽  
P. Lübcke ◽  
L. Vogel ◽  
U. Platt
Keyword(s):  
Theoretical Study ◽  
Point Sources ◽  
Imaging Method ◽  
Absorption Bands ◽  
Present Sample ◽  
Camera Systems ◽  
Fabry Perot ◽  
Band Absorption ◽  
Atmospheric Radiative Transfer ◽  
Dimensional Mapping

Abstract. We examine a new imaging method for the remote sensing of volcanic gases, which relies on the regularly spaced narrow-band absorption structures in the UV–VIS of many molecules. A Fabry–Perot interferometer (FPI) is used to compare the scattered sunlight radiance at wavelengths corresponding to absorption bands with the radiance at wavelengths in between the bands, thereby identifying and quantifying the gas. In this first theoretical study, we present sample calculations for the detection of sulfur dioxide (SO2). Optimum values for the FPI setup parameters are proposed. Furthermore, the performance of the FPI method is compared to SO2 cameras. We show that camera systems using an FPI are far less influenced by changes in atmospheric radiative transfer (e.g., due to aerosol) and have a great potential as a future technique for examining emissions of SO2 (or other gases) from volcanic sources and other point sources.

scholarly journals Interband plasmon polaritons in magnetized charge-neutral graphene

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
T. M. Slipchenko ◽  
J.-M. Poumirol ◽  
A. B. Kuzmenko ◽  
A. Yu. Nikitin ◽  
L. Martín-Moreno
Keyword(s):  
Transverse Electric ◽  
Near Field ◽  
Single Layer ◽  
Transverse Magnetic ◽  
Zero Temperature ◽  
Absorption Bands ◽  
Charge Carrier Dynamics ◽  
Quantum Phenomena ◽  
Plasmon Polaritons ◽  
The Magnetic Field

AbstractStudying the collective excitations in charge neutral graphene (CNG) has recently attracted a great interest because of unusual mechanisms of the charge carrier dynamics. The latter can play a crucial role for formation of recently observed in twisted bilayer CNG graphene plasmon polaritons (GPPs) associated with the interband transitions between the flat electronic bands. Besides, GPPs in CNG can be a tool providing insights into various quantum phenomena in CNG via optical experiments. However, the properties of interband GPPs in CNG are not known, even in the simplest configurations. Here, we show that magnetically-biased single-layer CNG can support interband GPPs of both transverse magnetic and transverse electric polarizations (particularly, at zero temperature). GPPs exist inside the absorption bands originating from the electronic transitions between Landau levels and are tunable by the magnetic field. We place our study into the context of potential near-field and far-field optical experiments.

scholarly journals Symmetry-broken square silicon patches for ultra-narrowband light absorption

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xin Yin ◽  
Tian Sang ◽  
Honglong Qi ◽  
Guoqing Li ◽  
Xun Wang ◽  
...  
Keyword(s):  
Light Absorption ◽  
Impedance Matching ◽  
Resonance Mode ◽  
Absorption Enhancement ◽  
Narrow Slit ◽  
Cavity Model ◽  
Fabry Perot ◽  
Wave Patterns ◽  
Refractive Index Sensors ◽  
Absorption Features

AbstractThe effect of ultra-narrowband light absorption enhancement is presented by using metamaterials with symmetry-broken square silicon patches (SSPs). The symmetry of the SSP can be broken by introducing a narrow slit deviating from its center. By breaking the symmetry of the SSPs, slit resonance mode with standing wave patterns can be excited, and the locations of the absorption peaks can be well estimated by using the Fabry-Pérot (F-P) cavity model. Although there is no excitation of surface plasmon resonance, ultra-narrowband light absorption can be achieved by minimizing the reflectance through perfect impedance matching and simultaneously eliminating the transmittance by the metallic substrate. Good ultra-narrowband absorption features can be maintained as the parameters of the buffer layer and the SSPs are altered. When this type of symmetry-broken SSPs-based metamaterial is used in refractive-index sensors, it shows excellent sensing properties due to its stable ultra-narrowband absorption enhancement.

A miniaturized flexible frequency selective surface for dual band response

2020 ◽  
pp. 1-7
Author(s):  
Durai Kanchana ◽  
Sankararajan Radha ◽  
Balakrishnapillai Suseela Sreeja ◽  
Esakkimuthu Manikandan
Keyword(s):  
Frequency Response ◽  
Transverse Electric ◽  
Frequency Selective Surface ◽  
Transverse Magnetic ◽  
Dual Band ◽  
Band Frequency ◽  
X Band ◽  
Stable Frequency ◽  
Frequency Selective ◽  
Ku Band

Abstract In this paper, a novel miniaturized and flexible dual band frequency selective surface (FSS) is presented. This FSS provides effective shielding in X-band and Ku- band, with a frequency response of 9.4 and 16.7 GHz, respectively. The proposed FSS provides 924 MHz bandwidth at X-band and 1.34 GHz bandwidth at Ku-band with an insertion loss of 20 dB. Moreover, the proposed design is polarization-independent and it provides stable frequency response at various angles of incidences for both transverse electric and transverse magnetic modes. More significantly, the proposed FSS analyzed the bandstop response of the selective frequency and also is suitable for conformal applications. A prototype of the proposed FSS is fabricated. The measured results and simulated results are good in agreement.

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