scholarly journals Tunable Graphene-based Plasmonic Perfect Metamaterial Absorber in the THz Region

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 194 ◽  
Author(s):  
Zao Yi ◽  
Jiajia Chen ◽  
Chunlian Cen ◽  
Xifang Chen ◽  
Zigang Zhou ◽  
...  
Keyword(s):  
Transverse Electric ◽  
Incident Angle ◽  
Fdtd Method ◽  
Transverse Magnetic ◽  
Metamaterial Absorber ◽  
Terahertz Region ◽  
Surrounding Refractive Index ◽  
Perfect Metamaterial Absorber ◽  
The Impact ◽  
Difference Time

The optical performance of a periodically tunable plasma perfect metamaterial absorber based on a square-square-circle array we propose in the terahertz region is analyzed in this work by the finite difference time domain (FDTD) method. We not only discuss the impact of various parameters such as period a, length L, radius R, and incident angle θ under transverse magnetic (TM)- and transverse electric (TE)-polarization on the absorption spectra of the absorber but also study the effect of the Fermi energy EF and relaxation time τ. Finally, we simulate the spectra as the surrounding refractive index n changes to better evaluate the sensing performance of the structure, producing a sensitivity S of the structure of up to 15006 nm/RIU. On account of this research, we find that the absorber is beneficial to sensors and detectors in the terahertz region.

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 Research on Perfect and Tunable Metamaterial Absorber Based on Crosshair-shaped Graphene

2021 ◽  
Vol 2109 (1) ◽  
pp. 012015
Author(s):  
Yiran Guo ◽  
Yunping Qi ◽  
Chuqin Liu ◽  
Weiming Liu ◽  
Xiangxian Wang
Keyword(s):  
Relaxation Time ◽  
Chemical Potential ◽  
Incident Angle ◽  
Fdtd Method ◽  
Reference Value ◽  
Metamaterial Absorber ◽  
Selective Absorption ◽  
Perfect Absorber ◽  
Wide Angle ◽  
Perfect Absorption

Abstract Graphene, as a new nano-material, according to the physical properties of electric field localization and selective absorption on light of surface plasmon resonance (SPR), a tunable, multi-band and wide-angle perfect absorber based on crosshair-shaped graphene is devised by using the Finite Difference in Time Domain (FDTD) method. In this paper, the effects of chemical potential, relaxation time, and incident angle of light on the absorptivity of graphene are systematically discussed. The simulation experiment shows that there are two absorption peaks with perfect absorption rate appeared in the study range, and the maximum modulation index can be obtained by changing the relaxation time. Finally, it proves that the absorber is insensitive to wide-angle of light. Thus, it is able to be concluded that the absorber has a great reference value to sensor, wireless communication, biomedical and other fields.

Quarter mode rectangular cavity-based perfect metamaterial absorber in the terahertz region

2019 ◽  
Vol 33 (36) ◽  
pp. 1950460 ◽  
Author(s):  
Xiaojie Lu ◽  
Zhongyin Xiao ◽  
Mingming Chen
Keyword(s):  
Normal Incidence ◽  
Wave Theory ◽  
Metamaterial Absorber ◽  
Metal Plate ◽  
Rectangular Cavity ◽  
Perfect Absorption ◽  
Analysis And Design ◽  
Terahertz Region ◽  
Perfect Metamaterial Absorber ◽  
Good Agreement

In this work, we present the analysis and design of a perfect metamaterial absorber (MA) based on quarter mode rectangular cavity in the terahertz region. This structure is consisted of a metal plate where three different size quarter mode rectangular cavities are vertically placed on. Based on rectangular-cavity-theory, a formula is proposed to calculate the resonant frequency, which provides a guidance for designing MAs of such type. In terms of normal incidence, the simulated results show that the MA has three resonance points on 4.1301 THz, 4.6051 THz and 5.1088 THz, respectively, which is in good agreement with the calculated results. Furthermore, we present the distribution of E-field in the cavity and use the standing wave theory to explain the physical mechanism of the perfect absorption. These results verify the application of resonant cavities in the field of MA.

scholarly journals A Tunable Terahertz Metamaterial Absorber Composed of Hourglass-Shaped Graphene Arrays

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 533 ◽  
Author(s):  
Yunping Qi ◽  
Yu Zhang ◽  
Chuqin Liu ◽  
Ting Zhang ◽  
Baohe Zhang ◽  
...  
Keyword(s):  
Fdtd Method ◽  
Bilayer Graphene ◽  
Metamaterial Absorber ◽  
Dual Band ◽  
Maximum Absorption ◽  
Monolayer Graphene ◽  
Selective Absorption ◽  
Chemical Potentials ◽  
Difference Time ◽  
Absorption Characteristics

In this paper, we demonstrate a tunable periodic hourglass-shaped graphene arrays absorber in the infrared (IR) and terahertz (THz) frequency bands. The effects of graphene geometric parameters, chemical potentials, periods, and incident angles on the pure absorption characteristics are studied by using the Finite Difference Time Domain (FDTD) method. In addition, this paper also analyzes the pure absorption characteristics of bilayer graphene arrays. The simulation results show that the maximum absorption reaches 38.2% for the monolayer graphene structure. Furthermore, comparing the bilayer graphene structure with the monolayer structure under the same conditions shows that the bilayer structure has a tunable dual-band selective absorption effect and has a higher maximum absorption of 41.7%. Moreover, it was found that there are dual-band tunable absorption peaks at 21.6   μ m and 36.3   μ m with the maximum absorption of 41.7% and 11%. The proposed structure is a convenient method which could be used in the design of graphene-based optoelectronic devices, biosensors, and environmental monitors.

Design of Polarization- and Incident Angle-Independent Perfect Metamaterial Absorber with Interference Theory

2014 ◽  
Vol 43 (11) ◽  
pp. 3949-3953 ◽  
Author(s):  
Furkan Dincer ◽  
Muharrem Karaaslan ◽  
Emin Unal ◽  
Oguzhan Akgol ◽  
Cumali Sabah
Keyword(s):  
Incident Angle ◽  
Metamaterial Absorber ◽  
Interference Theory ◽  
Perfect Metamaterial Absorber

Two Dimensional Photonic Filter with a Circular Resonant Cavity

2013 ◽  
Vol 712-715 ◽  
pp. 1751-1754
Author(s):  
Zhao Xia Wu ◽  
Yuan Long Shao ◽  
Wen Chao Li ◽  
Er Dan Gu
Keyword(s):  
Dielectric Constant ◽  
Resonant Cavity ◽  
Fdtd Method ◽  
Circular Ring ◽  
Two Dimensional ◽  
Transmission Characteristics ◽  
New Type ◽  
Micro Cavity ◽  
The Impact ◽  
Difference Time

A new type of the two dimensional photonic filter which includes two in-line waveguides and a circular ring resonant cavity is presented in this paper. By using Finite Difference Time Domain (FDTD) method, we calculated and demonstrated the broadband frequency response of the filter and analyzed the impact of changing the dielectric constant of the inner rods on the transmission characteristics of the filter. Compared with the transmission characteristics of a micro-cavity,our numerical results show that such a filter can transmit multiple narrowband signals simultaneously. The number of the passbands of the filter increases with the rings of inner dielectric rods in the cavity. The center wavelength of the passbands can be tuned by adjusting the dielectric constant of the whole rods and inner rods without changing the size of the cavity..

Design of graded honeycomb radar absorbing structure with wide-band and wide-angle properties

2018 ◽  
Vol 11 (2) ◽  
pp. 143-150 ◽  
Author(s):  
Yuchen Zhao ◽  
Fang Ren ◽  
Li He ◽  
Jinsheng Zhang ◽  
Yanning Yuan ◽  
...  
Keyword(s):  
Transverse Electric ◽  
Incident Angle ◽  
Wide Band ◽  
Transverse Magnetic ◽  
Magnetic Polarization ◽  
Wide Range ◽  
Transverse Magnetic Polarization ◽  
Radar Absorbing Structure ◽  
Theoretical Limitation ◽  
Good Agreement

AbstractIn this paper, the design of a graded honeycomb radar absorbing structure (RAS) is presented to realize both a wide bandwidth and absorption over a wide range of angles. For both transverse-electric and transverse-magnetic polarization, a fractional bandwidth of more than 118.6% is achieved for at least a 10 dB reflectivity reduction when the incident angle is <45°, an 8 dB reduction when the incident angle is <55° and a 5 dB reduction when the incident angle is <70°. Meanwhile the 10 dB reduction upper angle limit is approximately 30° for the uniform coating honeycomb RAS in the literature, which loses its absorbing ability when the incident angle is larger than 55°. Furthermore, the total thickness of our design is 10.7 mm, which is only approximately 1.29 times that of the theoretical limitation. The good agreement between the calculated, simulated, and measured results demonstrates the validity of this optimization.

Realization of tunable TE/TM wave splitter with one-dimensional plasma dielectric photonic crystal

2018 ◽  
Vol 32 (23) ◽  
pp. 1850253 ◽  
Author(s):  
K. F. Shen ◽  
B. Guo
Keyword(s):  
Magnetic Field ◽  
Photonic Crystal ◽  
Transverse Electric ◽  
Incident Angle ◽  
Transverse Magnetic ◽  
Dielectric Medium ◽  
Frequency Region ◽  
The Other ◽  
Reflection And Transmission ◽  
One Dimensional

A tunable transverse electric (TE) and transverse magnetic (TM) wave splitter using one-dimensional plasma dielectric photonic crystal which consists of plasma arranged periodically in a host dielectric medium is proposed. We performed a detailed study to explore the phenomena of reflection and transmission that occurs on obliquely incident electromagnetic wave propagating in the proposed plasma dielectric photonic crystal. We exactly calculated the transmittance based on the transfer matrix method. We find that if the parameters are selected appropriately, in the TE-stop or TM-stop frequency region, the other polarized component TM or TE wave is totally transmitted. The results also show that the dielectric constant, plasma thickness, incident angle and the applied magnetic field have significantly changed the properties of the TE/TM wave splitter. Moreover, the external magnetic field can be used as a kind of tunable method once the splitter is fabricated. Parameter dependence of the effects for the TE/TM wave splitter is calculated and discussed.

Impact of Fabrication and Operation Errors on Super-Focusing Performance of a Nanoslit-Based Metalens

2021 ◽  
Vol 16 (7) ◽  
pp. 1115-1119
Author(s):  
Shun Zhou ◽  
Yechuan Zhu ◽  
Shaobo Ge ◽  
Fei Xie ◽  
Na Jin ◽  
...  
Keyword(s):  
Transverse Electric ◽  
Incidence Angle ◽  
Incident Angle ◽  
Incident Light ◽  
Polarized Light ◽  
Super Resolution ◽  
Optical Manipulation ◽  
Optical Components ◽  
Operating Wavelength ◽  
The Impact

Metasurfaces with optical manipulation at subwavelength resolution show promises for developing ultrathin and flat optical components, attracting great interest from the optical scientific community. In our recent work, a metalens has demonstrated a special capability of quasi-far-field super-resolution focusing, which comprised a metallic nanoslit array with the incidence of a transverse-electric (TE) polarized light. In this paper, in order to guide practical fabrication and operation of a device, we perform a study on the metalens to analyze the impact of many imperfections on the super-resolution focusing capability. We take fabrication and operation errors into account, including errors in nanoslit width, metal film thickness, operating wavelength, polarization and incident angle of incident light. Numerical results illustrate that the sensitivity of the metalens focusing performance to each error is different. To be specific, the focusing performance of the metalens is considerably susceptible to the error in the incidence angle. Therefore, we not only need to fabricate the metalens device precisely, but also need to ensure that the working conditions agree well with the design, so as to achieve the desired focusing performance. Our research offers a valuable guide for the realization of the super-resolution focusing technology in practice.

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