Epsilon-negative Materials Research Articles

A Complementary Patch Loaded Epsilon Negative Artificial Material to Facilitate Miniaturization of S-Band Microwave Devices

The epsilon negative materials are found to have applications in the sensor development and microwave device integration for their performance enhancement. However, their existence for S-band operation suffers from relatively large size, the characterization with the bigger dimensions waveguide or horn, and improper permeability (μ 0 in the microwave S-band. The numerical analysis was validated by fabricating the unit-cell structure on a Rogers isotropic thermoset microwave material of relative permittivity ɛr = 12.85 and measuring its scattering parameters spectra using 50 Ω subminiature version-A elongated probe tapping and coupling method. The measured resonance of the transmission and reflection magnitude at 2.64 GHz and 2.85 GHz show a close matching with the simulated results. The material medium parameters of the unit-cell were calculated and verified. The applicability of the proposed epsilon negative unit-cell is shown by loading it in a two-port 50 Ω microstrip line, which then excites a stop-band resonance and yet maintains a low-profile. Therefore, such an artificial material may be used to facilitate miniaturization in the microwave circuit devices.

Reverse design of negative permittivity property in Nickel-Network/Epoxy composites

Epsilon-negative materials are usually prepared by additive manufacturing, while a reverse design method needs to be developed to construct the epsilon-negative materials by subtractive manufacturing. Here the Nickel-Network/Epoxy composites were prepared via a chemical corrosion and curing process. The connectivity of nickel network was weakened by chemical corrosion, which was companied with a change of conductivity mechanism from metal-type conductivity to the hopping conductivity. The negative permittivity value could be effectively adjusted by corroding the nickel network, which was attributed to low-frequency plasmonic state of nickel network. The reverse design method provided a novel and more flexible method to construct the desired the epsilon-negative materials.

Analysis of photonic band gap in photonic crystal with epsilon negative and double negative materials

The transmission properties of one-dimensional binary and ternary photonic crystals are theoretically investigated using transfer matrix method. The binary structure is composed of alternate layers of epsilon-negative and double-negative materials. The photonic band gap is analyzed by changing the permeability of epsilon negative material. It is found that the width of the photonic band gap increases with the increase of the permeability of epsilon negative material. It is also analyzed by varying the ratio of the plasma frequency to the resonance frequency in both materials. The width of the band gap increases with the increase of this ratio. A wider band gap of width 10.8 GHz can be achieved in ternary structures which contain an additional epsilon negative layer. It can be utilized in the microwave bands of X band, a portion of C band and Ku band as a double negative medium. A special kind of photonic band gap is found in both the binary and ternary structures.

Design of Zeroth-order resonance antenna array with a pair of DPS and ENG materials

This paper proposes one-dimensional antenna arrays of the four-element and the eight-element using composite materials. Firstly, the single element is designed to resonate at Zeroth-order using a pair of Double positive (DPS) and Epsilon negative (ENG) materials meta-structured transmission line (MTL). Secondly, three of 1:2 T-Junction power dividers and seven of 1:2 T-Junction power dividers based on micro-strip technology are designed for feeding the four-element and the eight-element array antennas, respectively. Finally, the proposed arrays are optimized using FEM-based simulation to operate at the frequency of 8,5 GHz. The simulated results show that both antenna arrays have Zeroth-order resonance (ZOR) property, in which the four-element array has a bandwidth spreading from 8.39 to 8.61 GHz and a maximum gain of 8.82 dB while the other one of the eight-element array is 8.39 – 8.60 GHz and 12.2 dB, respectively. The proposed array antennas can be used for wireless applications or mobile communications.

Photonic crystal with epsilon negative and double negative materials as an optical sensor

Two ternary photonic crystals are proposed for sensing applications. The first one is composed of an air layer as an analyte sandwiched between two double negative material (DNM) layers whereas the second one consists of an air layer sandwiched between two epsilon negative material (ENM) layers. The transmission spectrum is studied for two different values of the refractive index of the analyte layer with ∆n = 0.01. A specific peak in the transmission spectrum is observed and the wavelength at which the peak occurs is determined. The wavelength shift due to any change in the index of the analyte layer is also determined. The effect of varying the parameters of the DNM and ENM on the sensitivity of the sensor is discussed. It is found that the sensitivity of the structure ENM/air/ENM is much greater than that of the structure DNM/air/DNM and it is estimated as 26 times of the sensitivity of the latter structure.

Surface polaritons in grating composed of left-handed materials

In this work, we developed a unique mathematical model to solve dispersion relation for surface polaritons (SPs) in artificial composite materials grating. Here, we have taken two types of materials for analysis. In the first case, the grating composed of epsilon-negative (ENG) material and air interface. In second case, grating composed of left-handed materials (LHMs) and ENG medium interface is considered. The dispersion curves of both p and s polarized SPs modes are obtained analytically. In the case of ENG grating and air interface, polaritons dispersion curves exist for p-polarization only, whereas for LHM grating and ENG medium interface, the polaritons dispersion curves for both p and s polarization are observed.

Wave properties in asymmetric single-negative-base photonic crystals.

We theoretically study wave properties for one-dimensional defective asymmetric photonic crystals, air/(AB)MG(BA)N/air, air/(AQ)MG(QA)N/air, and air/(BQ)MG(QB)N/air, where A is a lossy epsilon-negative material, B is a lossy mu-negative material, G and Q are dielectrics with different refractive indexes, and M and N are stack numbers with M≠N. Special attention has been paid to their absorption spectra. It is found that at certain frequencies the absorption can exhibit unidirectional properties. Our calculated results show two kinds of unidirectional absorption peaks. One is a single absorption peak whose frequency depends on the thickness of defect layer G. For the other peaks, its frequency does not change when the defect layer's thickness changes. In addition, in the second kind of peaks, the peak numbers for forward and backward propagation are different, that is, there are (M-1) absorption peaks for forward propagation, while there are (N-1) absorption peaks for backward propagation. When the two kinds of unidirectional absorption peaks are merged, some new peaks appear, and both forward and backward propagation will have (M+N-1) absorption peaks.

Analysis of magneto-optical properties for three-dimensional photonic crystals in high-symmetry arrangement doped by metamaterials and uniaxial materials

Abstract In this paper, we use a modified plane wave expansion (PWE) method to investigate the properties of photonic band gaps (PBGs) for the extraordinary mode in the three-dimensional (3D) photonic crystals (PCs) which are composed of the anisotropic dielectric (the uniaxial materials) spheres immersed in the homogeneous metamaterials (epsilon-negative materials) background with high-symmetry (body-centered-cubic) lattices, as the magneto-optical Voigt effects are considered. The equations for calculating the PBGs in the first irreducible Brillouin zone are theoretically derived. It is numerically illustrated that the anisotropic PBGs and two flattened band regions can be achieved. The influences of the ordinary-refractive index, extraordinary-refractive index, filling factor of dielectric spheres, electronic plasma frequency and cyclotron frequency on the magneto-optical properties of such 3D PCs also are studied in detail, respectively, and some corresponding physical explanations are given. The numerical results demonstrate that the anisotropy can open partial band gaps in the proposed PCs, and the complete PBGs can be obtained compared with the conventional PCs only containing the isotropic material with similar structures. The bandwidths of PBGs can be tuned by introducing the epsilon-negative materials into such PCs containing the uniaxial materials. The anisotropic PBGs can be manipulated by the parameters as mentioned above. As the proposed PCs with high-symmetry lattices, the complete PBGs can be obtained by introducing the uniaxial materials.

Single Negative Metamaterial-Based Hollow-Core Bandgap Fiber With Multilayer Cladding

We propose a single negative metamaterial (MTM)-based hollow-core fiber with multilayer cladding employing zero-effective-phase bandgap for optical confinement in this paper. The cladding is formed from a ternary 1-D photonic crystal (T-1DPC) unit cell, which is basically a Mu-negative material sandwiched by different Mu-negative and Epsilon-negative materials. We demonstrate its capability for broadband transmission by numerically simulating and analyzing the photonic bandgap (PBG) and the modal loss characteristics. The results show that the T-1DPC-based cladding can effectively broaden the PBG. Compared with that for the binary 1-D photonic crystal unit cell-based fiber, the radiation loss for the T-1DPC-based fiber can be reduced by three orders of magnitude over most of the PBG range for equal number of unit cells. This MTM fiber, depending on the operating wavelength, shows surface plasmon guidance or classical wave guidance or both simultaneously. We also investigate the effect of variations in the design parameters and material absorption on the wave guidance of this fiber.

Resonant modes in photonic double quantum well structures with single-negative materials

The transmission spectra of the model of photonic double quantum well consisting of two photonic crystals with two different single-negative materials are calculated by the transfer matrix method. It is found that these resonance modes split into pairs, owing to a coupling between two photonic wells. The distance of resonant modes can be controlled by the coupling strength between the two wells. It is observed that when two photonic quantum wells are far from each other, resonance modes appear as single peak. And the quality factors of the transmittance resonance peaks can be greatly improved by increasing the period number of outer barriers. The resonance modes are affected weakly by the incident angle and polarization. The effects of the losses coming from epsilon-negative and mu-negative materials on the resonance modes are also specifically explored, respectively.

A broadband omnidirectional absorber based on a hetero-structure composed of epsilon-negative material and mu-negative material

A broadband omnidirectional absorber which is realized by heterostructures containing a collision plasma layer and a zero − n mirror is theoretically investigated. A collision plasma layer and an appropriate dielectric layer are put on the top of the PC. It is shown to absorb roughly 70% of all available electromagnetic wave in a relative omnidirectional absorption band width 244 MHz. The absorption band edge of the PC is influenced by the range of the reflection band gap. Meanwhile, the absorption range for the transverse magnetic (TM) wave decreases at large incident angle. Compared with some previous designs, our proposed structure has a relative flatter total absorption spectrum over a broad microwave frequency range and using a zero − n gap as a mirror is insensitive to the incident angle. This kind of heterostructure offers additional opportunities to design novel optoelectronic devices.

Study on the anisotropic photonic band gaps in three-dimensional tunable photonic crystals containing the epsilon-negative materials and uniaxial materials

In this paper, the properties of anisotropic photonic band gaps (PBGs) for three-dimensional (3D) photonic crystals (PCs) composed of the anisotropic positive-index materials (the uniaxial materials) and the epsilon-negative (ENG) materials with body-centered-cubic (bcc) lattices are theoretically studied by a modified plane wave expansion (PWE) method, which are the uniaxial materials spheres inserted in the epsilon-negative materials background. The anisotropic photonic band gaps (PBGs) and one flatbands region can be achieved in first irreducible Brillouin zone. The influences of the ordinary-refractive index, extraordinary-refractive index, filling factor, the electronic plasma frequency, the dielectric constant of ENG materials and the damping factor on the properties of anisotropic PBGs for such 3D PCs are studied in detail, respectively, and some corresponding physical explanations are also given. The numerical results show that the anisotropy can open partial band gaps in such 3D PCs with bcc lattices composed of the ENG materials and uniaxial materials, and the complete PBGs can be obtained compared to the conventional 3D PCs containing the isotropic materials. The calculated results also show that the anisotropic PBGs can be manipulated by the parameters as mentioned above except for the damping factor. Introducing the uniaxial materials into 3D PCs containing the ENG materials can obtain the larger complete PBGs as such 3D PCs with high symmetry, and also provides a way to design the tunable devices.

Investigation of the unusual surface plasmon modes and switching bandgap in three-dimensional photonic crystals with pyrochlore lattices composed of epsilon-negative materials

The unusual surface plasmon modes and switching bandgap of three-dimensional (3D) photonic crystals (PCs) with pyrochlore lattices that are composed of core isotropic positive-index dielectric spheres surrounded by epsilon-negative (ENG) material shells inserted in the air are theoretically investigated in detail based on the plane wave expansion method. Numerical simulations show that the proposed double-shell structure can obtain complete photonic band gaps (PBGs) and a flatbands region. Compared to the conventional lattices, such as diamond, face-centered-cubic, body-centered-cubic, and simple-cubic lattices, a larger PBG can be achieved in the pyrochlore arrangement. It is noticed that the flatbands region is determined by the existence of surface plasmon modes. If the thickness of the ENG material shell is larger than a threshold value, the band structures of such 3D PCs will be similar to those obtained from the same structure containing pure ENG material spheres. In this case, the inserted core spheres will also not affect the band structures. It is also provided that the upper edge of the flatbands region does not depend on the topology of the lattice. Our results also demonstrate that the PBG can be manipulated by the radius of the core dielectric sphere, the dielectric constant of ENG materials, and the electronic plasma frequency, respectively. This means that the PBG can be obtained by replacing the pure ENG material spheres with such double-shell structures to save the material in the realization. Thus, such proposed 3D PCs offer a novel way to realize the potential applications.

Research of Epsilon-Negative Material and its Electromagnetic Shielding Effect

This article discusses the physical theory and mathematical modeling of epsilon-negative (ENG) material. Numerical simulation results are also given in later part of this article, and they prove that this kind of material has a great shielding effect. We mainly focus on the modeling and simulation of one dimensional epsilon-negative (ENG) material. First we set up a Drude model to theoretically simulate ENG material, and then use the finite difference time-domain methods to analyze the electromagnetic wave propagation in our shielding material.

The anisotropic photonic band gaps in three-dimensional photonic crystals with high-symmetry lattices composed of metamaterials and uniaxial materials

In this paper, the properties of anisotropic photonic band gaps (PBGs) for three-dimensional (3D) photonic crystals (PCs) composed of tellurium (Te) spheres (the uniaxial materials) in homogeneous single-negative metamaterials (epsilon-negative materials) background with high-symmetry (simple-cubic) lattices are theoretically investigated based on the plane wave expansion method. The equations for calculating the anisotropic PBGs in the first irreducible Brillouin zone are theoretically deduced. The influences of the ordinary-refractive index, extraordinary-refractive index, filling factor of dielectric, the electronic plasma frequency, the dielectric constant of epsilon-negative materials on the anisotropic PBGs are also studied in detail, respectively, and some corresponding physical explanations are also given. The numerical results show that the anisotropy can open partial band gaps in simple-cubic lattices and the complete PBGs also can be achieved compared to such 3D PCs doped by the conventional isotropic materials. It also is shown that the anisotropic PBGs can be manipulated by the parameters as mentioned above. Introducing the uniaxial materials into 3D dielectric-epsilon-negative materials PCs can enlarge the PBGs, and also provide a way to obtain the complete PBGs as such kind of 3D PCs with high-symmetry lattices.

THE WAVELENGTH DIVISION MULTIPLEXER REALIZED IN THREE-DIMENSIONAL UNUSUAL SURFACE-PLASMON-INDUCED PHOTONIC CRYSTALS COMPOSED OF THE EPSILON-NEGATIVE MATERIALS SHELLS

In this paper, the dispersive properties and switching state of three-dimensional (3D) photonic crystals (PCs) with diamond lattices, which are composed of the core isotropic dielectric spheres with surrounded by the epsilon-negative (ENG) materials shells inserted in the isotropic dielectric background (air), are theoretically investigated in detail based on a modifled plane wave expansion method. The wavelength division multiplexer can be realized easily by tuning the switching state of such PCs. The equations for computing band structures for such 3D PCs are presented. Our analysis shows that the proposed double-shell structures can obtain the complete photonic band gaps (PBGs) which can be used to realize optical switching by manipulating the radius of core dielectric sphere, the relative dielectric constant of background, the dielectric constant of ENG materials and the electronic plasma frequency, respectively. However, the thickness of the ENG materials shell cannot change the switching state as the radius of core dielectric sphere is certain. Numerical simulations also show that a ∞atband region, and the stop band gaps (SBGs) in (1 0 0) and (1 1 1) directions which are above the ∞atband region can be achieved. The SBGs in (1 0 0) and (1 1 1) directions can also be tuned by the parameters as mentioned above. There also exists a threshold value for the thickness of ENG material shell, which can make the band structures for the 3D PCs with double-shell structures similar to those obtained from the same structure containing the pure ENG materials spheres. In this case, the inserted core sphere will not afiect the band structures. It means that we can achieve the PBGs by replacing the pure ENG materials spheres by such double-shell structures to make fabricate easily and save the material in the realization. It is also noticed that the ∞atband region is determined by the existence of surface-plasmon modes, and the upper edge of ∞atband region does not depend on the topology of lattice. Such presented 3D PCs with double-shell structures ofier a novel way to realize the wavelength division multiplexers.

ENHANCED THE COMPLETE PHOTONIC BAND GAPS FOR THREE-DIMENSIONAL PHOTONIC CRYSTALS CONSISTING OF EPSILON-NEGATIVE MATERIALS IN PYROCHLORE ARRANGEMENT

In this paper, the properties of photonic band gaps (PBGs) for three-dimensional (3D) photonic crystals (PCs) composed of isotropic positive-index materials and epsilon-negative materials with pyrochlore lattices are theoretically investigated by a modifled plane wave expansion method. The eigenvalue equations of calculating the band structures for such 3D PCs in the flrst irreducible Brillouin zone (spheres with the isotropic positive-index materials inserted in the epsilon-negative materials background) are theoretically deduced. Numerical simulations show that the PBG and a ∞atbands region can be achieved. It is also found that larger PBG can be obtained in such PCs structure than the conventional lattices, such as diamond, face-centered-cubic, body-centered-cubic and simple-cubic lattices. The in∞uences of the relative dielectric constant of spheres, fllling factor, electronic plasma frequency, dielectric constant of epsilon-negative materials and damping factor on the properties of PBG for such 3D PCs are studied in detail, respectively, and some corresponding physical explanations are also given. The calculated results also show that the PBG can be manipulated by the parameters mentioned above except for the damping factor. Introducing the epsilon-negative materials into 3D dielectric PCs can obtain the complete and larger PBG as such 3D PCs with pyrochlore lattices, and also provides a way to design the potential devices.

Study of the dispersive properties of three-dimensional photonic crystals with diamond lattices containing metamaterials

In this paper, the dispersive properties of three-dimensional photonic crystals with diamond lattices containing isotropic dielectric and metamaterials are theoretically studied by a modified plane wave expansion method. In order to simplify the study, one only kind of the metamaterials is considered—the epsilon-negative materials. The eigenvalue equations of their structure depending on the diamond lattice realization (spheres with epsilon-negative materials inserted in the dielectric background) are deduced. A photonic band gap (PBG), a flatband region, and the first two stop band gaps (SBGs) above the flatband region in the Γ–X and Γ–L directions are found to appear. The results show that the upper edge of the flatband region cannot be tuned by any parameters except for the electronic plasma frequency. The PBG and first SBGs above the flatband region in the Γ–X and Γ–L directions for PCs can be modulated by the filling factor, relative dielectric constant and electronic plasma frequency, respectively. However, the damping factor has no effect on the locations of first PBG and the SBGs above the flatband region in the Γ–X and Γ–L directions.

Investigating the dispersive properties of the three-dimensional photonic crystals with face-centered-cubic lattices containing epsilon-negative materials

In this paper, dispersive properties of three-dimensional (3D) photonic crystals (PCs) with face-centered-cubic (fcc) lattices composed of the isotropic positive-index materials and epsilon-negative materials are theoretically investigated based on a modified plane wave expansion (PWE) method. The eigenvalue equations of such structure (spheres with epsilon-negative materials inserted in the dielectric background) are deduced. The band structures can be obtained by solving such nonlinear eigenvalue equations. It can be obviously seen that a photonic band gap (PBG), a flat band region, and two stop band gaps (SBGs) in the Г-X and Г-L directions appear, respectively. The results show that the upper edges of flat band region cannot be tuned by any parameters except for the electronic plasma frequency. The first PBG and the first SBGs above the flat band region in the Г-X and Г-L directions for the 3D PCs can be modulated by the filling factor, relative dielectric constant and electronic plasma frequency, respectively. However, the damping factor has no effect on the locations of the first PBG and the first SBGs above the flat band region in the Г-X and Г-L directions. These results may provide theoretical instructions to design the future optoelectronic and communication devices containing epsilon-negative materials.

各向异性介质缺陷单负媒质光子晶体的新型缺陷模

A kind of zero-phase-shift gap appears in the one-dimensional photonic crystal composed ofalternate epsilon-negative materialand mu-negative material,and the gap does not vary with electromagnetic wave incident angle and polarization direction.To tune the defect mode frequency,a layer of anisotropic media is introduced into the center of that photonic crystal.The transmission spectra are investigated by Berreman 4×4 matrix.The result indicatesthat frequency of defect mode can be tuned by rotating the anisotropic media around z-axis in laboratory coordinate,and does not changed by different incident angles.These phenomena can be applied to tunable single tunnel omnidirectional filter in light wave.