Wave Propagation In Chiral Media Research Articles

Plane dilatational and shear waves in a chiral porous thermoelastic medium under strain gradient theory

PurposeThis study aims to investigate time-harmonic wave propagation in a chiral porous thermoelastic solid under strain gradient theory (SGT), focusing on identifying and characterizing distinct wave modes within the medium.Design/methodology/approachUsing Iesan's gradient theory, which incorporates chiral effects and accommodates second sound phenomena, the authors derive mathematical formulations for the velocities and attenuations of eight propagating waves: four dilatational waves and two pairs of coupled shear waves (one left circularly polarized, the other right). Numerical simulations are performed for a specific model, exploring the influence of various parameters on wave propagation.FindingsThe authors establish that the medium supports four dilatational waves, including a microstretch-associated wave, and four shear waves, distinguished by their chiral-induced characteristics. The results highlight the frequency-dependent dispersive nature of all propagating waves and establish connections with existing theoretical frameworks, demonstrating the broader applicability of our findings.Practical implicationsThe characteristics of wave propagation in chiral media examined here can enhance our understanding of chiral medium behavior. This knowledge is crucial for developing materials with pronounced chiral effects, surpassing those found in natural chiral materials like bone, quartz, sugar and wood. Advances in artificial chiral materials are driven by their superior toughness, durability and other beneficial properties. Consequently, this study has potential applications across various fields, including the design of chiral broadband absorbers and filters, the production of artificial bones and medical devices, aeronautical engineering and beyond.Originality/valueThis research extends existing theories and deepens the understanding by exploring wave behaviors in chiral media, advancing this emerging field.

Wave propagation in chiral media: composite Fresnel equations

In this paper, the author studies the features of wave propagation in chiral media. A general form of wave equations in biisotropic media is employed to derive concise formulas for the reflection and transmission coefficients. These coefficients are represented as a composite form of Fresnel equations for ordinary dielectrics, which reveal the circularly polarized nature of chiral media. The important features of negative refraction and a backward wave associated with left-handed waves are analyzed.

New properties of guided electromagnetic wave propagation in chiral media

AbstractIn this paper, we present a new study of the electromagnetic wave propagation inside a rectangular waveguide partially loaded with an isotropic chiral medium, by means of the coupled mode method. Along this analysis some new features related to the variation of the propagation constant versus frequency and the chirality parameter, which have not been previously reported in the literature, are introduced. Among them, we highlight the existence of a frequency point wherein all the dispersion curves cross each other, and the increasing of the cutoff frequency of the fundamental mode with the chirality of the medium. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1206–1212, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27534

A 2D-TLM model for electromagnetic wave propagation in chiral media

In this paper, a novel TLM algorithm for electromagnetic wave propagation in chiral media is presented. One of the main characteristics of the electromagnetic response of such media is the rotation of the polarization plane. The obtained TLM results for a monochromatic source are compared with the theoretical solution, and very good agreement is achieved. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 180–182, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20937

Optical properties of isotropic chiral media

A review is given of the optical properties of isotropic chiral media, based on the symmetrized constitutive relations of Condon. The review includes discussion of wave propagation in chiral media, and derivation of the reflection and transmission amplitudes of an isotropic optically active medium, and of a layer resting on a substrate. Boundary conditions and energy conservation relations are derived. For the chiral layer, simple formulae are given for the reflection and transmission coefficients at normal incidence, in the weak chirality limit, near the critical angles, and for a thin layer. Analytic expressions are given for all the reflection and transmission amplitudes in the general case. An ellipsometric method of measuring the chirality of very small sample volumes is suggested.

Modeling effective properties of chiral composites

After a brief overview of the concepts of electromagnetic chirality and wave propagation in chiral media, this paper deals with the field of microwave-chiral-material modeling. First, studies regarding the scattering of single-chiral or non-chiral elements with different shapes (various designs of helices, /spl Omega/-shaped scatterers, wires, and loops) are presented. Results of the backscattered field given by different computer codes are compared. Comparisons among analytical, numerical, and experimental results are also reported. Second, the case of a collection of chiral inclusions is treated. A review of different methods, developed to estimate average properties of helix-loaded materials, is given. Modeling of the effective properties of a chiral slab, such as the rotation angle, ellipticity, permittivity, and permeability, is explored. Reflection and transmission coefficients, evaluated by various methods, are compared with each other, and with measurements. Limitations of the models, possible improvements, and new directions for research are also described. Finally, applications of such composites to the design of radar-absorbing materials are addressed.