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Examines the electromagnetic signature of a polymer model that is consisted of tiny point-polarizable spheres strung on helical strands. Characteristics of chiral medium; Formula for the helical arrangement; Discussion on the result of the study.

The planar interface of an ordinary, isotropic, homogeneous, dielectric material and a hyperbolic, dielectric, structurally chiral material can support the propagation of one or multiple Dyakonov–Tamm waves, at a specified frequency and along a specified direction in the interface plane. When multiple Dyakonov–Tamm waves can exist, they differ in phase speed, propagation length, degree of localization to the interface, and spatial profiles of the associated electromagnetic fields. Dependence on the relative permittivity scalar of the isotropic partnering material suggests exploitation for optical sensing of analytes in fluids. [ABSTRACT FROM AUTHOR]

Abstract: A cascade of two slabs of dissimilar structurally chiral materials can function as a spectral hole filter for normally incident, circularly polarized light, provided (i) both have the same structural handedness and (ii) their constitutive parameters and thickness satisfy two matching conditions. When the total thickness of the cascade is relatively small, a narrow spectral hole is found in the reflection spectrum of co-handed light. Conversely, an ultranarrow spectral hole is found in the transmission spectrum of cross-handed light, when the total thickness of the cascade is relatively large. [Copyright &y& Elsevier]

Abstract: For a circularly polarized plane wave incident normally on a chiral sculptured thin film (STF), we determined that light pressure per unit thickness on the film is high when the incident plane wave and the chiral STF are co-handed, the loss factor in the chiral STF is as low as possible, the wavelength is either the center-wavelength of the Bragg regime or close to it, and the ratio of the film thickness normalized by the period is moderately high. [Copyright &y& Elsevier]

A slab of an isotropic material with structural chirality in the thickness direction and with either 43m or 23 point group symmetry exhibits the circular Bragg phenomenon in the optical regime, only on the application of a low-frequency electric field across its two faces. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2148–2153, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21941 [ABSTRACT FROM AUTHOR]

Abstract: The Oseen transformation is generalized to define a non-electro-optic structurally chiral material, wherein propagation along the axis of chirality is equivalent to that in an electro-optic SCM with local point group symmetry. This generalization shows that the exploitation of the Pockels effect amounts to an enhancement of the effective local birefringence, which in turn can enhance the characteristics of the circular Bragg phenomenon. Electro-optic SCMs can therefore serve as efficient and electrically controllable circular- and elliptical-polarization rejection filters. [Copyright &y& Elsevier]

Cascades of chiral sculptured thin films (STFs) with successive pitches forming a geometric series are theoretically shown to function as wideband circular-polarization filters. A simple design paradigm is provided. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 135–138, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20231 [ABSTRACT FROM AUTHOR]

A theory of reflection and transmission of normally incident plane waves to a chiral sculptured thin film (CSTF) is presented. It is based on a coupled wave approach, in which the handedness-reversing reflections at the medium's interfaces are combined with the handedness-preserving distributed reflection inside the CSTF. Explicit formulas for the various reflection and transmission coefficients are derived. The method is shown to provide acceptable quantitative agreement with the exact full electromagnetic analysis. [ABSTRACT FROM AUTHOR]

Using a numerical time-domain method, we studied the reflection and refraction of optical narrow-extent pulses by linear and cubically nonlinear chiral sculptured thin films (STFs). The incident signal consisted of a carrier plane wave whose amplitude was modulated by a pulse envelope. The carrier phase and the nonlinearity of the chiral STF were found to have significant effects on both the shape and magnitude – as described by the instantaneous Poynting vector – of the reflected pulses, particularly with respect to the circular Bragg phenomenon exhibited by chiral STFs. The provided results point towards uses of the nanoengineered STFs in optical communication and sensing devices. [Copyright &y& Elsevier]

Explains why the strong-property-fluctuation (SPFT) has gained prominence in the homogenization of linear composite mediums. Accommodation of the distributional statistics of the component phases; Formulation of the SPFT for cubically nonlinear isotropic chiral composite in mediums.

Radiation due to six canonical configurations for the source current density embedded in a structurally chiral medium is analyzed theoretically. The radiation spectrum is highly dependent on whether its source is co-chiral or cross-chiral, and is localized either in or on the edges of the Bragg regime. The obtained conclusions hold for both chiral liquid crystals and chiral sculptured thin films doped with fluorescent dyes, etc. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 37–40, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10818 [ABSTRACT FROM AUTHOR]

We demonstrate analytically that two types of spectral holes located approximately in the center of the Bragg regime could be exhibited by a slanted chiral sculptured thin film (STF) containing a 90° twist defect midway through its thickness. One is a nonspecular spectral reflection hole excited by an incident circularly polarized plane wave of the same handedness as the chiral slanted STF, and the other a specular transmission hole excited by an incident circularly polarized plane wave of the opposite handedness. The occurrences of these holes depend on the device thickness, and a crossover thickness can be defined. The existence of both types of spectral holes is sensitive to the dual-periodicity of the slanted chiral STF, and can be completely subverted by the Rayleigh–Wood phenomenon. [Copyright &y& Elsevier]

An ellipsoid-based structure–property relationship model for a chiral sculptured thin film (STF) infiltrated with a chiral fluid is presented. The effect of the constitutive and microstuctural parameters on the optical response of the chiral STF is explored. Specific structure–property relations are developed. The model predicts that infiltration by a chiral fluid shifts the spectral location of the Bragg regime, and this shift is linearly dependent on the degree of chirality of the fluid. The bandwidth of the Bragg regime also changes. Finally, the model also predicts that the chiral fluid can either enhance or diminish the optical activity exhibited by a chiral STF. Which of these effects occurs depends on the microstructural and constitutive parameters of the chiral STF and the constitutive parameters of the chiral fluid. [Copyright &y& Elsevier]

Here the Bragg-Pippard (BP) formalism is extended in order to homogenize linear bianisotropic-in-bianisotropic particulate composites, assuming the inclusion particles to be ellipsoidal. The BP formalism yields satisfactory results as the inclusion volume fraction f → 1, unlike the Maxwell Garnett (MG) formalism but like the Bruggeman formalism. However, the BP formalism is asymmetric with respect to the two component mediums in the same way as the MG formalism is, but the Bruggeman formalism can be symmetric. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 40–44, 2002; DOI 10.1002/mop.10225 [ABSTRACT FROM AUTHOR]

A material combining both mirror-conjugated and racemic chirality properties is characterized and classified within the context of linear bianisotropic mediums. Planewave propagation in the chosen material is studied with particular emphasis on the interaction of different and no handedness along certain specified directions. Comparison is made with isotropic chiral mediums as well as uniaxial bianisotropic mediums. [ABSTRACT FROM AUTHOR]

The chiroferrite medium is conceptualized as a homogenized composite medium (HCM) comprising a magnetically biased ferrite and an isotropic chiral medium as its components. Numerical results are presented which show unambiguously that the HCM is fully bianisotropic with all four constitutive dyadics endowed with a gyrotropic structure. The magnetoelectric response properties depend critically on the chirality parameter and the volume fraction of its isotropic chiral component. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 18: 342–345, 1998. [ABSTRACT FROM AUTHOR]

Comments on an article about accelerated particle radiation in chiral media. Equations which have been successful in explaining the behavior of time-harmonic fields in chiral media; Measurement of the effect of chirality; Factor attributed to optical rotation and circular dichroism.

Abstract: While growing a chiral sculptured thin film by physical vapor deposition, a sudden change in the direction of the vapor flux creates a plane of discontinuity. In effect, this is a planar interface between two different structurally chiral materials. Theoretical analysis shows that more than one Dyakonov–Tamm waves, with different phase speeds and degrees of localization to this interface, may propagate in different directions guided by the interface. [ABSTRACT FROM AUTHOR]

The net light pressure on a chiral sculptured thin film, for normal incidence, can be maximized by appropriately choosing the vapor incidence angle during the fabrication of the film by physical vapor deposition. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1407–1409, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22407 [ABSTRACT FROM AUTHOR]

The concept of cross-refractive chiral media is proposed, and the plane-wave response of a planar interface between two such media is determined. The proposed concept—along with the related concepts of isoimpedant and isorefractive chiral chiral media—completes a study on constitutive contrasts between two isotropic chiral media. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 20: 337–339, 1999. [ABSTRACT FROM AUTHOR]

The frequency-dependent constitutive relations of a simple symmetric bianisotropic medium (SSBM) are stated as ${\b D}= {A}{\kern-0.8em \raise -1ex\hbox{=}} \cdot (\epsilon {\b E}- \beta {\b H}) \hbox{ and } {\b B}= {A}{\kern-0.8em \raise -1ex\hbox{=}} \cdot (\beta {\b E} + \mu {\b H})$, where A??? is a real symmetric dyadic. After an affine transformation is used, expressions for the fields in the source regions are derived for this medium. The obtained results may be used to determine the scattering response of an electrically small bianisotropic particle embedded in a SSBM, and can therefore also be used to homogenize a wide class of particulate composites. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 15: 84–86, 1997. [ABSTRACT FROM AUTHOR]

It is shown that impedance matching delivers two specific benefits for chirolens design. First, there is no left-handed ↔ right-handed field conversion inside a nonhomogeneous chirolens with a spatially constant impedance. Second, when the chirolens is impedance matched to the surrounding free space, the incident, the scattered and the internally induced fields have the same handedness. In addition, the backscattered field of an impedance-matched, radially nonhomogeneous, spherical chirolens is null in tire far zone. [ABSTRACT FROM AUTHOR]

The phase velocity of plane waves propagating in an isotropic chiral medium can be simultaneously positive for left-circularly polarized light and negative for right-circularly polarized light (or vice versa). The constitutive parameter regimes supporting this phenomenon are established for nondissipative and dissipative mediums. The boundary between positive- and negative-phase velocity is characterized by infinite phase velocity. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1245–1246, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22434 [ABSTRACT FROM AUTHOR]

Negative real parts of the permittivity and permeability lead an isotropic chiral medium to exhibit circular dichroism that is reversed with respect to that exhibited by an identical medium, the real parts of which have positive permittivity and permeability. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 96–97, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10239 [ABSTRACT FROM AUTHOR]

A dyadic differential operator that commutes with the curl dyadic can be used to obtain new solutions of the Faraday and the Amperé–Maxwell equations in linear, homogeneous chiral media. Conditional extension of this representation theorem to bianisotropic media is also possible. An admissible operator may involve fractional derivatives. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 28: 385–386, 2001. [ABSTRACT FROM AUTHOR]

Multiple compound surface plasmon-polariton (SPP) waves can be guided by a structure consisting of a sufficiently thick layer of metal sandwiched between a homogeneous isotropic dielectric (HID) material and a dielectric structurally chiral material (SCM). The compound SPP waves are strongly bound to both metal/dielectric interfaces when the thickness of the metal layer is comparable to the skin depth but just to one of the two interfaces when the thickness is much larger. The compound SPP waves differ in phase speed, attenuation rate, and field profile, even though all are excitable at the same frequency. Some compound SPP waves are not greatly affected by the choice of the direction of propagation in the transverse plane but others are, depending on metal thickness. For fixed metal thickness, the number of compound SPP waves depends on the relative permittivity of the HID material, which can be useful for sensing applications. [ABSTRACT FROM AUTHOR]

Abstract: A high-speed humidity sensor based on a nanostructured chiral sculptured thin film (CSTF) was fabricated and tested. The sensing principle is based on the shift of the central wavelength of the circular Bragg regime of the CSTF caused by adsorption and desorption of water vapor in the void regions of the CSTF. Spectral changes due to varying relative-humidity (RH) levels in the ambient environment were measured by a spectrometer. The CSTF sensor exhibited excellent reversibility and reproducibility from 40% to 100% RH. Moreover, the adsorption time of the sensor was measured to be as low as ∼140ms, making it promising for many high-speed humidity-sensing applications. [Copyright &y& Elsevier]