Right-handed Material Research Articles

Chiral MoS2@BC fibrous membranes selectively promote peripheral nerve regeneration

BackgroundMolybdenum disulfide (MoS2) has excellent physical and chemical properties. Further, chiral MoS2 (CMS) exhibits excellent chiroptical and enantioselective effects, and the enantioselective properties of CMS have been studied for the treatment of neurodegenerative diseases. Intriguingly, left- and right-handed materials have different effects on promoting the differentiation of neural stem cells into neurons. However, the effect of the enantioselectivity of chiral materials on peripheral nerve regeneration remains unclear.MethodsIn this study, CMS@bacterial cellulose (BC) scaffolds were fabricated using a hydrothermal approach. The CMS@BC films synthesized with L-2-amino-3-phenyl-1-propanol was defined as L-CMS. The CMS@BC films synthesized with D-2-amino-3-phenyl-1-propanol was defined as D-CMS. The biocompatibility of CMS@BC scaffolds and their effect on Schwann cells (SCs) were validated by cellular experiments. In addition, these scaffolds were implanted in rat sciatic nerve defect sites for three months.ResultsThese chiral scaffolds displayed high hydrophilicity, good mechanical properties, and low cytotoxicity. Further, we found that the L-CMS scaffolds were superior to the D-CMS scaffolds in promoting SCs proliferation. After three months, the scaffolds showed good biocompatibility in vivo, and the nerve conducting velocities of the L-CMS and D-CMS scaffolds were 51.2 m/s and 26.8 m/s, respectively. The L-CMS scaffolds showed a better regenerative effect than the D-CMS scaffolds. Similarly, the sciatic nerve function index and effects on the motor and electrophysiological functions were higher for the L-CMS scaffolds than the D-CMS scaffolds. Finally, the axon diameter and myelin sheath thickness of the regenerated nerves were improved in the L-CMS group.ConclusionWe found that the CMS@BC can promote peripheral nerve regeneration, and in general, the L-CMS group exhibited superior repair performance. Overall, the findings of this study reveal that CMS@BC can be used as a chiral nanomaterial nerve scaffold for peripheral nerve repair.Graphical

Constituents of electromagnetic 2-D layered media Green's functions for all material types and radiation conditions

Layered media Green's functions (LMGFs) are obtained for line sources with complex longitudinal wavenumbers in planarly layered media by numerically evaluating Sommerfeld integrals. The results obtained in this article can be applied to the numerical analysis of structures in layered media composed of any combination of right-handed materials (RHMs) and left-handed materials (LHMs). In the derivation, due to the complex-valued longitudinal wavenumber values, two different boundary conditions are used to include plane waves with: (i) decaying and (ii) outgoing Poynting vectors in the LMGFs. As a result, two completely different LMGFs are obtained by using two different radiation conditions and corresponding Sommerfeld integration paths (SIP) that are rigorously tailored on the complex integrand plane. In this work, all the necessary numerical tools for calculating the 2-D LMGFs are provided to be implemented in a computer program from scratch.

Engineered photonic spin Hall effect of Gaussian beam in antisymmetric parity-time metamaterials

A model of the photonic spin Hall effect (PSHE) in antisymmetric parity-time (APT) metamaterials with incidence of Gaussian beams is proposed here. We derive the displacement expression of the PSHE in APT metamaterials based on the transport properties of Gaussian beams in positive and negative refractive index materials. Furthermore, detailed discussions are provided on the APT scattering matrix, eigenstate ratio, and response near exceptional points in the case of loss or gain. In contrast to the unidirectional non-reflection in parity-time (PT) symmetric systems, the transverse shift that arises from both sides of the APT structure is consistent. By effectively adjusting the parameters of APT materials, we achieve giant displacements of the transverse shift. Finally, we present a multi-layer APT structure consisting of alternating left-handed and right-handed materials. By increasing the number of layers, Bragg oscillations can be generated, leading to an increase in resonant peaks in transverse shift. This study presents a new approach to achieving giant transverse shifts in the APT structure. This lays a theoretical foundation for the fabrication of related nano-optical devices.

TEM-wave propagation in a coaxial waveguide with impedance-matched RHM to LHM transition.

In this paper, we study TEM-wave propagation inside a hollow coaxial waveguide filled with an inhomogeneous metamaterial composite, with a graded transition between a right-handed material (RHM) and an impedance-matched left-handed material (LHM). The graded transition and the TEM-wave propagation occur in the direction perpendicular to the boundary between the two media, which has been chosen to be the z-direction. The relative permittivity ɛ(ω, z) and permeability µ(ω, z) of the RHM-LHM composite vary according to hyperbolic tangent functions along the z-direction. The exact analytical solutions to Maxwell's equations are derived, and the solutions for the field components and wave behavior confirm the expected properties of impedance-matched RHM-LHM structures. Furthermore, a numerical study of the wave propagation over an impedance-matched graded RHM-LHM interface, using the COMSOL Multiphysics software, is performed. An excellent agreement between the analytical results and numerical simulations is obtained, with a relative error of less than 0.1%. The present method has the ability to model smooth realistic material transitions, and includes the abrupt transition as a limiting case. Finally, the RHM-LHM interface width is included as a parameter in the analytical and numerical solutions, allowing for an additional degree of freedom in the design of practical devices using RHM-LHM composites.

Folded Resonator for Glucose Solution Density Detection Based on Airy Beam Arrays

We presented an investigation on the evolution properties of the finite Airy beam array (FAiBA) in metamaterial’s slab system constituting of right-handed materials and double negative materials combining the generalized Huygens–Fresnel integral equation and the light transfer matrix. The beam intensity distribution on the receiver plane and its side transmission view on the (z, x) plane are demonstrated numerically with several array numbers. Moreover, we put forward a kind of folded resonator to detect glucose solution density based on the derived principle and conclusion; the influence of curvature radius on the emerging beam’s evolution characteristics is discussed, and the empirical formula between FAiBA’s received power and glucose solution density is derived by using the fit linear analysis. We hope that the present concept and the derived conclusions can be employed for monitoring in the environmental field, as well as the biomedical and food safety detection.

The transverse electric plasmonic modes in a negative refractive index black phosphorene waveguide structure

We consider the transverse electric (TE) plasmonic modes supported by black phosphorene (BP) in a parallel waveguide structure with left-handed material (LHM) instead of the conventional right-handed dielectric material. The existence condition of the TE BP surface plasmon polariton (SPP) is . When an electric field is polarized along one of the two orthogonal crystal axes, the anisotropic symmetric and anti-symmetric plasmonic modes depend on the incident optical energy, the chemical potential, and the distance between two BP sheets can be observed. The symmetric mode has a more extensive effective refractive index, which possesses stronger field confinement. With a decreasing distance d between two BP sheets, the coupling strength between the two separate BPSPP waves increases. When d is small enough, the anti-symmetric mode root does not exist. LHMs can be used to realize a TE BPSPP mode to enhance the localization of the BPSPP, which is a practical method in optoelectronic devices based on black phosphorene.

Calculation of Transmission Characteristics of Shielded Microstrip Lines Filled with Anisotropic Left-Handed and Right-Handed Materials

In this paper, the edge-based finite element formula for calculating the transmission characteristics of shielded microstrip lines filled with anisotropic materials with magnetic field as working variable is derived in detail. The filling materials include anisotropic left-handed materials and anisotropic right-handed materials, and the transmission characteristics include dominant mode cutoff wavelength and electric field structure. We mainly take Rectangular-shaped, V-shaped and Trapezoidal-shaped shielded microstrip lines as examples to calculate the transmission characteristics. The formulas and calculation examples derived in this paper have strong guiding significance for the application of anisotropic left-handed and right-handed materials in inhomogeneous transmission lines, which will further expand the use of shielded microstrip lines in optical devices such as electro-optic waveguide modulators.

Controlled switching of the optical surface waves in one-dimensional photonic crystals containing left-handed materials in the presence of a chiral metamaterial as a cap layer

We theoretically investigated the localization and switching properties of surface waves that appear at the interface between the homogeneous medium and a semi-infinite one-dimensional photonic crystal in the presence of chiral metamaterial as a cap layer, using the transfer matrix method. The one-dimensional photonic crystal is made of alternating layers of right-handed and dispersive left-handed materials, and both forward and backward surface waves were appeared in this structure. It was demonstrated that the chirality parameter of the cap layer plays a significant role in tuning the type (changing forward to backward and vice versa) and localization of surface waves with transverse electric polarization. We believe that our results provide a useful way for a deeper understanding of the properties of surface waves in photonic devices and metamaterial systems.

左右手材料光子晶体带隙及表面波局域电场特性

左右手材料光子晶体带隙及表面波局域电场特性

左右手材料光子晶体带隙及表面波局域电场特性

左右手材料光子晶体带隙及表面波局域电场特性

Propagation of Bessel Gaussian beam through slabs of right-handed materials and left-handed materials

By using of ABCD matrix method and Collins diffraction theory, the analytical expression of the complex amplitude of the Bessel Gaussian beam propagating through slabs of right-handed materials and left-handed materials is deduced. The Bessel Gaussian beam can be regarded as the modulated Bessel beam that the Bessel beam multiplies the Gaussian factor as a function of the beam waist radius. Effects of the half-cone angle and the beam waist radius on propagation properties of the Bessel Gaussian beam through slabs of right-handed materials and left-handed materials are discussed. The results show that the propagation trajectories and the lobes of the Bessel Gaussian beam can be controlled by the half-cone angle and the beam waist radius.

Propagation properties of radially and azimuthally polarized chirped Airy-Gaussian vortex beams through slabs of right-handed materials and left-handed materials.

By using Huygens-Fresnel diffraction integral formula and the transfer matrix method, the analytical expression of radially and azimuthally polarized chirped Airy-Gaussian vortex beams through left-handed materials and right-handed materials can be obtained. We study the effects of the chirp factor and the distribution factor on the radially and azimuthally polarized chirped Airy-Gaussian vortex beams in the propagation process, including the light intensity, the phase distribution, the propagation path, the peak intensity, and the radiation force. The focal position of the beams can be adjusted by the chirp parameter.

Computational analysis of cutoff wavenumbers in rectangular waveguides filled with left‐handed material and/or right‐handed material

This paper investigates the cutoff wavenumbers and their geometric and dielectric dependence in rectangular waveguides filled with left-handed material (LHM) and/or right-handed material (RHM). A rigorous hybrid mode analysis of these structures produces the dispersion equations and the formulations of cutoff wavenumbers for the first three modes. It is shown how the geometric and dielectric parameters may influence the cutoff wavenumbers of the waveguides filled with LHM and/or RHM. The graphs of cutoff wavenumbers over a range of geometric and dielectric parameters sufficiently wide to cover most requirements of design and application have been plotted. The cutoff wavenumbers of waveguides with LHM increase as the thicknesses or the absolute values of permittivity of LHM increase. It is noted that the variation rules of cutoff wavenumbers in waveguides with LHM show different changing tendencies compared with the waveguides with RHM.

Electromagnetic waves' self-focusing in metamaterials having both LHM and RHM behavior: an application to filter design

ABSTRACTSelf-focusing, also known as Talbot’s effect had been widely studied by the scientific community. In this paper we show self-focusing as a coherence propagation phenomenon, in particular we studied self-focusing for a pulse propagating in a metamaterial with both behaviors: left handed material (LHM) and right handed material (RHM). These dual behaviors allow the construction of frequency filters in the range of frequency in which the metamaterial stops behaving as a LHM (negative refraction index) and begins an RHM behavior (positive refraction index). The coherence length (CL) for pulses propagating in these metamaterials seems to be larger when its frequencies are in the LHM region. Finally, we show that the cell’s size turns out to be critical in designing the filter, and as an example we present here four metamaterial cells.

Effects of the multi-order and off-axis vortex on quadratically chirped Airy beams in the right-handed and left-handed materials slabs

Based on the ABCD matrix and Huygens diffraction integral, the expressions for the quadratically chirped Airy vortex (QCAiV) beams with vortex’s arbitrary position and vortex’s topological charge propagating in the right-handed (RHMs) and left-handed materials (LHMs) slabs are deduced. The effects of the position and the topological charge m of the vortex on the intensity distribution, the intensity concentration, the peak intensity, diffraction range and radiation forces are deeply investigated in the paper. It is shown that the acceleration of the optical vortex is always bigger than that of the corresponding QCAiV beams in both RHMs and LHMs slabs. Therefore, with suitable position of the vortex, plurality of intersections of the vortex and the QCAiV beams can be achieved and the intensity concentration can be controlled during propagation. The range of the diffraction can be controlled by the off-axis vortex and it depends on the relative distance from vortex to the origin. At last, we demonstrate the effect of the vortex on the maximum scattering force and gradient force distribution on the Rayleigh dielectric particles respectively.

Propagation properties of radially and azimuthally polarized chirped-Airy vortex beams through slabs of right-handed materials and left-handed materials

With the transfer matrix method, analytical expressions of radially and azimuthally polarized chirped-Airy vortex beams (RPCAiVBs and APCAiVBs, respectively) through right-handed materials and left-handed materials are derived. We mainly discuss the effects of the radial and azimuthal polarizations as well as the effects of the chirped parameter on the propagation properties, including the propagation trajectory, the transverse intensity and the phase distributions, the peak intensity, the radiation forces, and the transverse orbital and spin currents of the RPCAiVBs and APCAiVBs in the x direction, the y direction, and their synthesizing direction. It is shown that the x, y, and synthesizing directions of the RPCAiVBs and APCAiVBs satisfy the vector synthesis rule, owing to the axial symmetry, and intensity modulation of the RPCAiVBs and APCAiVBs can be achieved by varying the chirped parameter.

Propagation Properties of Airy Beam through Periodic Slab System with Negative Index Materials

Based on light transfer matrix and electric field vector equation, the evolution of Airy beam propagating in periodic slab system with three negative index materials (NIMs) and its transmission mechanism are investigated. The intensity profiles on emergent surface of periodic slab system and side view of Airy beam propagating in each right handed material (RHM) and double negative material (DNM) unit including lossless and losses DNMs are discussed. It is revealed that the self-recovery Airy beam can be achieved in long distance by using lossless periodic slab system as long as the negative refractive index nl=-nr and each unit length L=Z. As to losses slab system contained DNMs, the smaller the collision frequencies are, the better the Airy beam quality is formed. It is expected that the proposed manner of beam transmission and corresponding conclusions can be useful for extension applications of optical control, especially for optical communication and optical encryption technique.

Dynamic Propagation of Quadratically Chirped Airy Beams in the Right-Handed and Left-Handed Material Slabs

We analytically and numerically investigate the dynamic propagation of the quadratically chirped Airy beams in right-handed material (RHM) and left-handed material (LHM) slabs. Based on the analytical expressions and numerical calculations, we find that through choosing the appropriate value of the quadratic chirp, one can modify the diffraction, the intensity distribution, the propagation path, and acceleration and deceleration of the quadratically chirped Airy beams to meet the actual usage accordingly. In addition, we also demonstrate the effect of the quadratic chirp on the Poynting vector and the angular momentum of the quadratically chirped Airy beams, respectively. Furthermore, we explore the gradient and scattering forces on a Rayleigh dielectric particles induced by the quadratically chirped Airy beams.

Propagation properties of the chirped Airy vortex beams through left-handed and right-handed material slabs

We present an investigation on the propagation properties of the chirped Airy vortex (CAiV) beams through slabs of left-handed materials (LHMs) and right-handed materials (RHMs). We discuss the influence of chirped parameter C on the propagation of the CAiV beams through LHM and RHM slabs. Our simulation results show that a maximum accelerated velocity appears during the propagation process. The intensity concentration of the CAiV beams increases with the absolute value of the chirped parameter. The peak intensity of the CAiV beams changes abruptly, and the chirped parameter plays an active role on the difference of the maximum and the minimum. In the energy flow, we find that the effects of the chirped parameter on the strength of the vortex are different at different propagation distances.

Wave Propagation Solution for Transverse Electric Mode in a Graded Interface between Left-Handed and Right-Handed Material

Wave propagation for transverse electric (TE) mode in a graded interface between left-handed and right-handed material has been investigated by using asymptotic iteration method. By using hyperbolic functions for negative permittivity and negative permeability, we obtained the graded graphs of permittivity and permeability as a function of material thickness. Maxwell equation for the dielectric with the hyperbolic function in permittivity and permeability has been reduced to second orde differential equation. The second orde differential equation has been solved by using asymptotic iteration method with the eigen functions in complementary error functions. The eigen functions explained about the wave propagation in a graded interface of material. The distribution of the electric field and the wave vector were given in approximate solution.