Left-handed Materials Research Articles

Layered Babinet complementary patterns acting as asymmetric negative index metamaterial

Azimuthal orientation and handedness dependence of the optical responses, accompanied by asymmetric transmission and asymmetric dichroism, were demonstrated on multilayers constructed with subwavelength periodic arrays of Babinet complementary miniarrays, illuminated by linearly and circularly polarized light. In case of single-sided illumination asymmetric optical responses were observed at the spectral location of maximal cross-polarization that is accompanied by radiative electric dipoles and weak, slowly-rotating in-plane magnetic dipoles on the nano-objects; where the outgoing waves are elliptically (almost circularly) polarized. The negative index material phenomenon was demonstrated, where the electric and magnetic dipoles overlap both spatially and spectrally. The negative index material (NIM) phenomenon is accompanied by electric multipoles that add up non-radiatively and correlates with the strong, pronouncedly-tilted, rotating magnetic dipoles characteristic on the nano-entities, where the outgoing waves are linearly (slightly elliptically) polarized. By illuminating the multilayer with two counter-propagating circularly polarized beams it was proven that asymmetrical normal component displacement currents at the bounding interfaces, arising along flat and tilted bands, accompany the asymmetric copolarized and cross-polarized transmission. The latter correlates with the asymmetric dichroism in the cross-polarized signal observed in case of single-sided circularly polarized light illumination. The dispersion maps in the single-sided asymmetrical co-polarized reflectance and absorptance indicate flat bands of analogous and complementary extrema, proving the partially dichroic nature of the observed asymmetric phenomena. The Tellegen (chirality) coefficients exhibit a maximum in a spectral region coincident with the asymmetric transmission (maximal polarization rotation in the 90° azimuthal orientation). The multilayer is proposed as an ultrathin NIM and nonreciprocal nanophotonic element.

Self-Assembly of Colloidal Dumbbell Isomers and Plasmonic Properties for Optical Metamaterials.

In this study, we explore the self-assembly of various colloidal symmetric dumbbell (DB) isomers, including dipole Janus, cis-Janus, trans-Janus, apolar-inward and polar-inward perpendicular Janus, and alternating perpendicular Janus DBs. Using dissipative particle dynamics (DPD) simulations under conditions mimicking experimental setups, we investigate cluster formation driven by emulsion droplet evaporation. Our findings reveal a diverse set of cluster structures, which are in good agreement with experimental and simulation results reported in the literature while also predicting the formation of novel cluster configurations. These structures, characterized by well-defined and predictable patterns, are potentially applicable to creating colloidal molecules and crystals. Furthermore, we examine the dynamics of cluster formation to gain insight into the mechanisms guiding the self-assembly of these diverse colloidal DBs. The study highlights the impact of particle isomerism on the resulting assembly structures. We further select a set of typical nanoclusters obtained, including a tetrahedral cluster, which is the simplest, to study its plasmonic properties. Our findings indicate that increasing the nanoparticle (NP) radius or decreasing the gap between NPs leads to a red shift in the plasmonic resonance wavelength and enhances the resonance strength. We identify critical parameter regions where the electric-dipole and magnetic-dipole resonances can be engineered to achieve negative dielectric permittivity and magnetic permeability, which are essential for developing negative-index metamaterials.

Design of Unit Cells-Based Metamaterial Antenna

Abstract Artificial metallic structures with simultaneous negative permittivity (ɛ) and permeability (µ) that result in a negative refractive index are known as metamaterials. It supports backward waves, i.e., group velocities and inside Metamaterial phase velocities are antiparallel, because of its negative index. The shortcomings of a regular patch antenna, such as low gain and efficiency, can be overcome with the help of this metamaterial antenna, which is helpful for wireless communication. The shortcomings of a regular patch antenna, such as low gain and efficiency, can be overcome with the help of this metamaterial antenna, which is helpful for wireless communication. The effort is justified by the proposal to use DNG (Double Negative) Metamaterials to create compact planar antennas. Additionally, it has peculiar features when compared to materials that are easily obtained because of its negative permeability and permittivity, which results in a negative refractive index. Owing to the unique characteristics of Metamaterials, the antenna achieves 3.768 dB, 53.76 % overall efficiency, and a 1.6 VSWR at 5 GHz frequency using a single unit cell. These results are excellent for wireless LANs and point-to-point communication. Additionally, a different metamaterial antenna with three unit cells produces superior results at 5 GHz frequency, with a return loss of -13.51 dB, a gain of 5.19.17 dB, and an overall efficiency of 92.50% at 2.4 GHz, the results are 4.1830 dB, 60.78%, and -14.51 dB, respectively.

Optical characterization of reduced graphene Based composite thin films: Left- Handed Materials (Metamaterials)

Negative index material is a type of metamaterial with negative refractive index; being an artificial material, its fabrication is quite difficult, scaling up the production to meet the commercial demand is a challenge and the strong energy dissipation by metals poses another difficulty. This study employed a low cost, scalable technique (Electrodeposition) to synthesis Al and Ca doped NiO-ZnO-rGO thin films on fluorine doped tin oxide (FTO) without any complexing agents. The thin films were optically characterized using double Spectrophotometer within 300-1000 nm wavelength. Results reveal low absorption for all films but high transmittance of max. 78 % for luminum doped thin films. The incorporation of Al3+ and Ca2+ indicate the optical band gap of NiO-ZnO-rGO shifted to low energy (2.0 eV) and high energy (2.20 eV) respectively. All the composite thin films have unique features; negative refractive indexes, negative imaginary dielectric constant, and negative optical conductivity. These optical results of the films show they are novel left handed materials suitable for wider applications such as telemedicine, internet of things, transmission lines, energy storage devices, bio sensing, wearable devices etc.

Vibration energy harvester design and experimental study based on double-negative metamaterials

Vibration energy harvester design and experimental study based on double-negative metamaterials

Exploring the dynamic interplay of intermodal and higher order dispersion in nonlinear negative index metamaterials

Our study delves into the intricate interplay of various factors within metamaterials, with a focus on modulation instability. Through our research, we elucidate the intricate dynamics involving intermodal dispersion, self-steepening effect, higher order dispersion, and plane wave amplitude, showcasing their competition and influence on modulation instability phenomena. We aim to explore the impact of intermodal dispersion and higher-order effects by numerically solving the generalized nonlinear Schrödinger equation (NLSE), which models the propagation of a few-cycle pulse in a nonlinear metamaterial. Our modulation instability (MI) analysis captures the complex dynamics these factors introduce. We demonstrate the spatiotemporal evolution of MI under different parameter values, revealing how these variations influence the instability’s development and characteristics. This approach provides a detailed understanding of the system’s behavior across various conditions, highlighting the roles of intermodal dispersion and higher-order effects. We demonstrate that the behavior of modulation instability bands and their reliance on parameters such as self-steepening and wave amplitude is contingent upon the specific characteristics of the optical setup and medium dispersion properties

Mixing Rules for Left-Handed Disordered Metamaterials: Effective-Medium and Dispersion Properties.

Left-handed materials are known to exhibit exotic properties in controlling electromagnetic fields, with direct applications in negative reflection and refraction, conformal optical mapping, and electromagnetic cloaking. While typical left-handed materials are constructed periodic metal-dielectric structures, the same effect can be obtained in composite guest-host systems with no periodicity or structural order. Such systems are typically described by the effective-medium approach, in which the components of the electric permittivity tensor are determined as a function of individual material properties and doping concentration. In this paper, we extend the discussion on the mixing rules to include left-handed composite systems and highlight the exotic properties arising from the effective-medium approach in this framework in terms of effective values and dispersion properties.

Electromagnetic characteristics analysis of dual-frequency magnetic single negative metamaterials

Abstract With the development of multi-frequency wireless transmission technology, it is necessary to expand the research of single-frequency metamaterials in the multi-frequency field. The dual-frequency metamaterial studied adopts a nested square spiral structure, which can resonate at two frequencies, and the real part of the equivalent permeability of metamaterial changes dramatically at the resonance frequency, and the equivalent electromagnetic parameter exhibits anomalous characteristics in the two frequency bands. Firstly, the effects of the number of turns, the width of the copper wire, the spacing of the copper wire, and the length of the outermost edge of inner and outer helical coils are investigated, respectively, using the HFSS software on the resonance frequency of dual-frequency metamaterials, which improves the study of dual-frequency metamaterials with nested square spiral structure. Then, based on the results of the change rule of resonance frequency with the four types of influencing factors, the dual-frequency metamaterials with the real part of the equivalent permeability close to -1 at 6.78 MHz and 13.56 MHz are designed, which is of certain reference significance for the subsequent practical design of dual-frequency metamaterials to satisfy the needs of the project.

Structural, morphological, optical and electrical properties of ferrite-based nanoparticles synthesized flexible substrate for chemical sensing application

A compact CaxCo(0.90-x)Zn0.10Fe2O4 based nanoparticles synthesized flexible microwave substrate with single negative (SNG) metamaterial is being successfully fabricated for industrial chemical contamination sensing applications. The unit cell dimensions of the MTM are 0.114λ × 0.114 λ × 0.017 λ. The nanoparticles, derived from the CaxCo(0.90-x)Zn0.10Fe2O4 material with varying Ca concentrations (Ca25, Ca50, and Ca75), have been synthesized using a sol-gel method, and their structural, morphological, and dielectric properties have been comprehensively characterized. Dielectric constants and loss tangents have been measured over the frequency range of 2–20 GHz. Simulation of the S21 response at 3.43 GHz, 6.50 GHz, 11.49 GHz, and 16.46 GHz has yielded maximum magnitudes of −52.78 dB, −48.07 dB, −52.16 dB, and −39.37 dB, respectively. Experimental verification on an FR-4 rigid substrate at 3.28 GHz, 6.58 GHz, 11.76 GHz, and 16.33 GHz has revealed magnitudes of −25.67 dB, −24.56 dB, −31.13 dB, and −25.17 dB. Finally, when fabricated on the flexible microwave substrate, the MTM displayed S21 responses of −48.31 dB, −43.12 dB, −61.80 dB, and −24.70 dB at 3.19 GHz, 6.62 GHz, 11.58 GHz, and 16.65 GHz, respectively. The MTM has exhibited SNG properties in distinct frequency bands and near-zero index (NZI) characteristics. The sensitivity, figure of merit (FOM), and Q-factor have been achieved at 0.096 GHz/RIU, 0.152 GHz/RIU, 0.846 (RIU−1), 0.846 (RIU−1), and 8.430, 29.801, respectively. Its performance has been validated through simulation, VNA measurements, and advanced design system (ADS) software analysis, showcasing promise for diverse applications in S-, C-, X-, and Ku-bands. The anticipated structure performs well in terms of its small size, flexibility, sensitivity, and lightweight, making it suitable for wireless communications and methanol and ethanol contamination sensing in industrial applications.

Wave optics in silver and silver nihility structure

This research article thoroughly explores the electromagnetic behavior in silver metal at optical regime. Along the way, it uncovers some intriguing wave behaviors in terms of novel phenomenon – counterposition, negative phase velocity (NPV), orthogonal phase velocity (OPV) and/or negative refraction (NR), versus wavelength are investigated which is not previously deeply discussed in a silver configuration. Additionally, Minkowski momentum densities, revealing complex wave dynamics versus optical wavelength are studied first time for silver metal. Moreover, the influence on wave in silver metal due to L-nihility is notified fruitfully. These findings provide deeper insights platform for potential applications in diverse scientific and technological domains in condense matter physics, engineering and optics.

Surface plasmon induced quantum interference at meta-material interface

In this work we investigate quantum interference in a four-level atom coupled to a negative index meta-material (NIMM) anisotropic plasmonic environment that supports both TE and TM polarized surface plasmons (SP). The analysis confirms the creation of the anisotropic environment and two dipoles can interfere with each other even if they are orthogonal by sharing such SP modes. The NIMM/plasmonic environment provides more options to control SP interaction with emitters and their spontaneous emission decays and spectrum. The spectrum depends critically on structure parameters, mode frequency, frequency dependent electric permittivity and magnetic permeability, and the location of the atom etc. We observe orders of magnitudes enhancement in the plasmonic-modified decays and spectrum compared to free space case.

Interconnected Circular Ring Resonator based Single Negative Perfect Metamaterial Absorber for Wireless Communication Systems

Interconnected Circular Ring Resonator based Single Negative Perfect Metamaterial Absorber for Wireless Communication Systems

Modulation instability in nonidentical metamaterial waveguide arrays by graph Laplacian approach

We theoretically investigate modulation instability (MI) in a nonidentical waveguide array, which is made up of positive and negative index metamaterial waveguides. The unit cell of the optical waveguide array consists of three waveguides arranged in a triangular manner. Waveguides 1 and 3 are made up of positive index material (PIM) channels and waveguide 2 is by negative index material (NIM) channels, as a result, they show different light propagation characteristics. We model this array of waveguides using a generalized nonlinear Schro¨dinger equation, replacing the Laplacian operator with the graph Laplacian. Following linear stability analysis, we will discuss MI for different values of transverse wave number, as it determines the order of the Brillouin zone. We also discuss the effect of input power on periodic MI in normal and anomalous dispersion regimes. Thus we report a comprehensive study on the MI and hence the better ways to generate and manipulate the solitons or ultra-short pulses in NIM PIM waveguide arrays.

Performance study and improvement of space-folded metamaterial muffler for pipe under grazing flow

A space-folded metamaterial muffler (SMM) for pipe noise attenuation was proposed in this paper, and an improved space-folded metamaterial muffler (ISMM) was formed by arranging wire meshes at the branch inlet. Under the absence of flow and grazing flow, analytical models of SMM and ISMM were developed based on the wave expansion method and Green's function, and correspondingly, the computational fluid dynamics - linear Navier-Stokes (CFD-LNS) numerical models were established. The acoustic characteristics of responsive space (RS) were described through the complex frequency plane. The transmission coefficient of SMM was obtained and verified by sound transmission loss experiments. The results indicate that due to the thermal-viscous effects, the minimum transmission coefficient of RS cannot reach 0. Therefore, the thermal-viscous effect is one of the critical factors. By the parameter retrieving method, it is clarified that the SMM is a single-negative acoustic metamaterial. The effect of the grazing velocity on the transmission coefficient and impedance was revealed quantitatively. The grazing velocity is positively correlated with impedance at the side branch inlet and negatively correlated with total impedance. Therefore, an increase in the grazing velocity will weaken the muffler performance. Since the CFD-LNS model cannot characterize aerodynamic noise, a computational aeroacoustics (CAA) model was established for SMM and ISMM. Numerical results show that the velocity and vorticity at the side branch inlet significantly decrease due to the wire mesh. When Ma is 0.1, 0.05, and 0.01, ISMM reduces aerodynamic noise by 6.11 dB, 9.19 dB, and 2.76 dB, respectively, compared to SMM. Therefore, ISMM has better aerodynamic noise suppression capability. Finally, noise reduction experiments of the ISMM under the grazing flow were performed in an anechoic chamber, and the effectiveness of the ISMM in practical applications was verified by acoustic imaging and spectrogram results.

Stabilization of hollow Gaussian beams in nonlinear metamaterial waveguides

Hollow Gaussian beams which possess the dark hollow spatial intensity distribution were found to have interesting applications in trapping nano-sized particles and free-space optical communication. Many applications demand stable dynamics of higher dimensional beams. Here we theoretically study the dynamics of hollow Gaussian beams in cubic and quintic nonlinear negative index metamaterial. We adopt Lagrangian variational analysis and explore the parametric regions characterizing the metamaterial in which the hollow Gaussian beam can execute stable dynamics as well as it can undergo filamentation due to intrinsic collapse. We confirm the analytical results obtained through variational analysis by direct numerical analysis based Crank Nicolson method implemented in Python programming.

Substrate-thickness dependence of negative-index metamaterials at optical frequencies

Optical metamaterials have attracted intensive attention in recent years for their broad applications in superlenses, electromagnetic cloaking, and bio-sensing. Negative refractive index (NRI) metal–dielectric–metal fishnet metamaterials (MMs) are typically used for beyond-diffraction-limit imaging. However, there are few reports about the substrate-thickness dependence of NRI, which strongly affects the practical application. In our study, it is demonstrated that the membrane-based NRI MMs with a more negative index work better than the bulk substrate-based counterparts. In addition, a regular periodic vibration of NRI with the thickness of the membrane substrate was theoretically studied. The destructive interference of the thin film can explain this phenomenon. Furthermore, the proposed explanation was further proved by substituting the dielectric spacer with a larger permittivity. Therefore, an NRI structure on a membrane substrate with constructive interference can be a good choice in ultra-compact photoelectronic devices. This study can be a guide to the practical application of ultracompact NRI devices.

A novel 3D polygonal double-negative mechanical metamaterial with negative stiffness and negative Poisson’s ratio

Materials with negative stiffness (NS) and materials with negative Poisson’s ratio (NPR) are two fundamental classes of mechanical metamaterials. The previous researches of double-negative metamaterials with simultaneous negative stiffness and negative Poisson’s ratio are either limited to two dimensions or challenging to realize experimentally. Here, a three-dimensional polygonal double-negative (PDN) metamaterial is proposed, which is formed by the auxetic framework and NS dome contact pairs. The main principle is that auxetic behavior is realized by sliding mechanism, whereby the sliding parts convert the applied vertical load into the horizontal compression load of the NS dome units, thus generating the negative stiffness characteristics. The double-negative metamaterial with quadrilateral profile shape (QDN) is studied by theoretical analysis and FEA simulation, and the response of the inversed-stacked QDN structure is verified by experiments. Furthermore, double-negative metamaterials with quadrilateral, hexagonal and cylindrical profile shapes are presented and their displacement conversion efficiency and Poisson’s ratio are analyzed and compared. The 3D polygonal double-negative structure can be applied to energy absorption due to its frictional action and elastic large deformation.

High isolation 16-port massive MIMO antenna based negative index metamaterial for 5G mm-wave applications

A 16-port massive Multiple-Input-Multiple-Output (mMIMO) antenna system featuring a high gain and efficiency is proposed for millimeter-wave applications. The antenna system consists of 64 elements with a total size of 17 λo × 2.5λo, concerning the lowest frequency. Each 2 × 2 (radiating patch) subarray is designed to operate within the 25.5–29 GHz frequency range. The antenna's performance in terms of isolation, gain, and efficiency has been significantly improved by utilizing the proposed unique double and epsilon negative (DNG/ENG) metamaterials. The array elements are positioned on top of a Rogers RT5880 substrate, with ENG metamaterial unit cells interposed in between to mitigate coupling effects. Additionally, the DNG metamaterial reflector is positioned at the rear of the antenna to boost the gain. As a result, the metamaterial-based mMIMO antenna offers lower measured isolation reaching 25 dB, a maximum gain of 20 dBi and an efficiency of up to 99%. To further analyze the performance of the MIMO antenna, the diversity gain and enveloped correlation coefficient are discussed in relation to the MIMO parameters.

Transverse electric guided modes in metal-LHM-ferrite slab waveguide structures

Transverse electric guided modes in metal-LHM-ferrite slab waveguide structures

Frequency-tunable quartic soliton in nonlinear negative-index metamaterials

An exact quartic soliton solution along with its constraint conditions in metamaterials (MMs) is presented on the basis of the nonlinear Schrödinger equation (NLSE) with second-, third- and fourth-order diffraction. Through analyzing the parameter relations based on the Drude model, it is demonstrated that the quartic soliton can only exist in the negative-index region (NIR) of self-focusing nonlinear MMs. With insight into the underlying parameter relations of quartic soliton, it is found that by selecting suitable frequency of incident wave, the quartic soliton in negative-index MMs (NIMs) exhibits frequency tunability or frequency stability. Particularly, the quartic solitons with different frequencies can propagate in an identical velocity, which provides a theoretical basis for realizing frequency division multiplexing (FDM) technology in nonlinear MMs. Different from pure-quartic soliton (PQS) in ordinary materials exhibiting oscillatory decaying tails in spatial domain and a flat top in frequency domain on logarithmic scale, the quartic soliton reported here possesses triangular distributions in both spatial and frequency domains. The presented results contribute to a fundamental theoretical support for future application of quartic soliton and are beneficial for exploring new solitary waves in MMs.