Dual-band Perfect Metamaterial Absorber Research Articles

Tunable dual-band perfect metamaterial absorber based on a graphene-SiC hybrid system by multiple resonance modes

We propose dynamically tunable dual-band perfect absorption of light in a composite structure, which consists of a graphene ribbon array coated on a dielectric layer, a silicon carbide (SiC) film and a distributed Bragg reflector (DBR). Two absorption peaks reaching 98.8% at 10.87 μm and 97.5% at 12.4 µm are observed in the hybrid structure. The dual-band absorption enhancement can be explained by two different mechanisms: one is attributed to the graphene localized surface plasmons (GLSP), and the other is originated from the excitation of Tamm plasmon polaritons (TPP) at the interface between SiC and DBR. Moreover, the high absorption peaks can be modulated by altering the geometrical parameters or dynamically controlling the chemical potential of graphene ribbons. More significantly, we numerically and theoretically investigate the hybridization between GLSP mode and TPP mode, which is characterized by the anti-crossing behaviour of the two modes. The mode splitting phenomenon is a typical Rabi splitting. In addition, we also study the coupling characteristics based on graphene surface plasmons (GSP) mode and TPP mode. This work offers a new paradigm for enhancing light–matter interaction through multiple resonance modes, and the proposed device could provide potential applications in MIR plasmonic devices, such as absorbers, detectors, and modulators, etc.

Dual-band tunable perfect metamaterial absorber based on graphene.

In this paper, a dual-band perfect metamaterial absorber based on graphene is proposed in the terahertz region. The metamaterial absorber consists of two sizes of graphene disks and a gold film separated by a dielectric spacer in a unit cell. The numerical results demonstrate that the dual-band perfect absorption can be achieved by the superposition of the specific absorption peaks induced by different disks. The resonance frequency can be tuned via controlling the graphene conductivity and the sizes of the disks. The metamaterial absorber can achieve selectively frequency tunability and it can tune each resonance independently. And the dual-band absorption will not be changed when the small disks move along the diagonal within the range of our research. In addition, owing to the symmetry of the structure, the absorber is insensitive to polarization and can keep a high absorptivity with a wide angle. The flexible and simple design makes it possible for our proposed single-layer graphene absorber to be applied in many metamaterial fields, such as sensing, detecting, and cloaking objects.

Ultra-subwavelength thickness for dual/triple-band metamaterial absorber at very low frequency

An integrated model utilizing external parasitic capacitors for a dual-band metamaterial perfect absorber (DMPA) is proposed and demonstrated in the UHF radio band. By adjusting the lumped capacitors on a simple meta-surface, the thickness of absorber is reduced to be only 1/378 and 1/320 with respect to the operating wavelength at 305 and 360.5 MHz, respectively. The simulations and the experiments confirm that the DMPA can maintain an absorption over 91% in a wide range of incident angle (up to 55°) and independent of the polarization of incident radiation. Additionally, we examine the integrated model for smaller dual-band absorber and absorption performance at higher frequencies (LTE band). Finally, we consolidate our approach by fabricating an ultrathin triple-band perfect absorber miniaturized to be only 1/591 of the longest operating wavelength. Our work is expected to contribute to the actualization of metamaterial-based devices working at radio frequency.

Two-layered Dual-band Perfect Metamaterial Absorber at K band Frequency

This paper presents a study of a novel absorber structure based on two-dielectric-layers, two perfect absorption frequency bands at K band (f1 = 26.5 GHz and f2 = 28.6 GHz) go under observance. The study of the dependence of absorption and frequency on relative distance between the layers of material and the material structure parameters are discussed.

Polarization-independent, wide-incident-angle and dual-band perfect absorption, based on near-field coupling in a symmetric metamaterial

We numerically and experimentally investigated a dual-band metamaterial perfect absorber (MPA), utilizing the near-field coupling of double split-ring resonators (DSRRs). Owing to the near-field coupling between resonators, two arms in each DSRR resonate in different phases, leading to a dual-band perfect absorption. The proposed MPA also exhibits polarization-insensitive behavior and maintains the high absorption above 90% up to a wide range of incident angle more than 45°. Finally, to further consolidate our approach, a multi-band absorption is also studied by exploiting the near-field coupling among a larger number of DSRRs. Our work is expected to be applied to future broadband devices using MPA.

Ultra-Thin Dual-Band Polarization-Insensitive and Wide-Angle Perfect Metamaterial Absorber Based on a Single Circular Sector Resonator Structure

We present a simple design for an ultra-thin dual-band polarization-insensitive and wide-angle perfect metamaterial absorber (PMMA) based on a single circular sector resonator structure (CSRS). Both simulation and experimental results reveal that two resonance peaks with average absorption above 99% can be achieved. The dual-band PMMA is ultra-thin with total thickness of 0.5 mm, which is <l/38 with respect to the operation frequencies. The surface electric field and current distributions of the unit-cell structure reveal the physical picture of the dual-band absorption. Numerical simulations demonstrate that the PMMA could retain high absorption level at large angles of polarization and incidence for both transverse electric (TE) and transverse magnetic (TM) modes. Furthermore, the absorption properties of the PMMA can be adjusted by varying the geometric parameters of the unit-cell structure.

Selective dual-band metamaterial perfect absorber for infrared stealth technology

We propose a dual-band metamaterial perfect absorber with a metal–insulator–metal structure (MIM) for use in infrared (IR) stealth technology. We designed the MIM structure to have surface plasmon polariton (SPP) and magnetic polariton (MP) resonance peaks at 1.54 μm and 6.2 μm, respectively. One peak suppresses the scattering signals used by laser-guided missiles, and the other matches the atmospheric absorption band, thereby enabling the suppression of long-wavelength IR (LWIR) and mid-wavelength IR (MWIR) signals from objects as they propagate through the air. We analysed the spectral properties of the resonance peaks by comparing the wavelength of the MP peak calculated using the finite-difference time-domain method with that obtained by utilizing an inductor–capacitor circuit model. We evaluated the dependence of the performance of the dual-band metamaterial perfect absorber on the incident angle of light at the surface. The proposed absorber was able to reduce the scattering of 1.54 μm IR laser light by more than 90% and suppress the MWIR and LWIR signatures by more than 92%, as well as maintain MWIR and LWIR signal reduction rates greater than 90% across a wide temperature range from room temperature to 500 °C.

Dual-band metamaterial perfect absorber with nearly polarization-independent

This paper presents the analysis of dual-band metamaterial perfect absorber (MPA) with nearly polarization-independent in X-band frequency. The resonating elements are designed using a rectangular ring structure, a slotted cross-structure, and a cross-structure. The resonating elements are printed on the top surface of FR4 substrate, while a full copper layer is printed at the opposite surface. The performance of the dual-band MPA is observed using CST software. From simulation, the proposed structure achieves almost perfect absorbance, which is 99.31 and 97.37% at 8 and 12 GHz, respectively, for normal incident electromagnetic wave. For oblique incident angles, it is observed that the operating angle (50% absorption limit) is 77° for both TE and TM polarizations.

Dual band metamaterial perfect absorber based on Mie resonances

We numerically and experimentally demonstrated a polarization insensitive dual-band metamaterial perfect absorber working in wide incident angles based on the two magnetic Mie resonances of a single dielectric “atom” with simple structure. Two absorption bands with simulated absorptivity of 99% and 96%, experimental absorptivity of 97% and 94% at 8.45 and 11.97 GHz were achieved due to the simultaneous magnetic and electric resonances in dielectric “atom” and copper plate. Mie resonances of dielectric “atom” provide a simple way to design metamaterial perfect absorbers with high symmetry.

Dual band metamaterial perfect absorber based on artificial dielectric "molecules".

Dual band metamaterial perfect absorbers with two absorption bands are highly desirable because of their potential application areas such as detectors, transceiver system, and spectroscopic imagers. However, most of these dual band metamaterial absorbers proposed were based on resonances of metal patterns. Here, we numerically and experimentally demonstrate a dual band metamaterial perfect absorber composed of artificial dielectric “molecules” with high symmetry. The artificial dielectric “molecule” consists of four “atoms” of two different sizes corresponding to two absorption bands with near unity absorptivity. Numerical and experimental absorptivity verify that the dual-band metamaterial absorber is polarization insensitive and can operate in wide-angle incidence.

Design and characterization of a dual-band perfect metamaterial absorber for solar cell applications

This paper proposes a metamaterial absorber design for solar energy harvesting using a simplified and symmetric structure. A unit cell of this design consists of three important layers namely, the bottom metallic layer, which is gold lossy, the intermediate layer: made of a lossy dielectric material that is gallium arsenide and patches which formed by a combination of gold and gallium arsenide. These three important layers are being carefully arranged at the top of a dielectric spacer. The geometric structure was being examined for its contribution towards absorption characteristics. The simulation results show outstanding dual-bands absorption (99.96% and 99.37%) in the visible frequency regime of electromagnetic wave. Due to the excellent symmetric nature of the proposed structure, its absorptance capacity exhibits polarization insensitivity for a wide range of incident angles for electromagnetic radiation.

Dual-band perfect metamaterial absorber for solar cell applications

The efficiency of solar photovoltaic (PV) cells has been one of the major problems impeding its global adoption as one of the sustainable substitutes to fossil fuel based technologies. Metamaterial (MTM) based solar cells offer an opportunity towards increasing the system efficiency by enhancing the total absorbed solar radiation incident on this device. In this study, a nanostructure-based MTM perfect absorber has been designed and simulated. By adjusting geometrical parameters and MTM structure properties, nearly perfect dual-band absorptions have been obtained with 99.99% and 99.90% absorption at 543.75 THz and 663.75 THz, respectively. The proposed structure is simple and more flexible for scaling, which helps achievement of multiple-band absorption. Implementation of the intended MTM structure can effectively lead to the realization of more efficient PV solar cells.

Polarization-independent dual-band perfect absorber utilizing multiple magnetic resonances

We propose a dual-band metamaterial perfect absorber at microwave frequencies. Using a planar metamaterial, which consists of periodic metallic donut-shape meta-atoms at the front separated from the metallic plane at the back by a dielectric layer, we demonstrate the multi-plasmonic high-frequency perfect absorptions induced by the third-harmonic as well as the fundamental magnetic resonances. The origin of the induced multi-plasmonic perfect absorption was elucidated. It was also found that the perfect absorptions at dual peaks are persistent with varying polarization.

Metamaterial Electromagnetic Wave Absorbers (Adv. Mater. 23/2012)

The image shows a dual-band metamaterial perfect absorber. The structure, described on page OP98 by W. J. Padilla and co-workers, is made of a checkerboard pattern of two gold crosses on a ground plane separated by a dielectric. The crosses of different sizes resonate at two frequencies, causing an impedance match condition and hence unity absorption at those frequencies. In this rendering, the incoming light (white) and the reflected white (red) are seen where green and blue light have been absorbed.