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A boundary-value problem was formulated for perturbation of an electrostatic field by a coated dielectric sphere made of two distinct linear anisotropic dielectric (LAD) materials. Specific affine transformations were employed to represent the electric potential inside the core and the coating in terms of the solutions of the Laplace equation. A transition matrix was found to relate the source potential and the perturbation potential in the exterior region. The formulation can be straightforwardly extended to concentrically multilayered spheres made of several homogeneous LAD materials. [ABSTRACT FROM AUTHOR]

Faster communication between electronic devices inside a semiconductor chip may be enabled by optical interconnects based on surface-plasmon-polariton (SPP) waves, as their high localization overcomes the size mismatch between optical and electronic devices. Hence, we solved the Maxwell equations in the time domain to investigate the jump of a pulse-modulated carrier SPP wave across a semi-infinite gap on the metallic side of a planar metal/dielectric interface. The Drude model was used for the susceptibility of the metal and the air was taken as the dielectric material in our calculations. The Pearson correlation coefficient of the appropriate component of the Poynting vector at two points on either side of the gap was calculated. After an abrupt termination of the metal, reflection was very low and the signal continued to propagate in air as a precursor followed by a somewhat distorted version of the launched pulse. Information encoded as the existence of a pulse was found to be strongly and positively correlated with the transmitted signal. When the metal/air interface was restored after a gap of width equal to the carrier wavelength in free space, the signal received across the gap still comprised a precursor and a main pulse that were still strongly and positively correlated with the transmitted signal. Thus, information continued to propagate in the forward direction for a long distance after the gap, a promising result for SPP-wave-based optical interconnects. [ABSTRACT FROM AUTHOR]

The boundary-value problem for the perturbation of an electric potential by a homogeneous anisotropic dielectric sphere in vacuum was formulated. The total potential in the exterior region was expanded in series of radial polynomials and tesseral harmonics, as is standard for the Laplace equation. A bijective transformation of space was carried out to formulate a series representation of the potential in the interior region. Boundary conditions on the spherical surface were enforced to derive a transition matrix that relates the expansion coefficients of the perturbation potential in the exterior region to those of the source potential. Far from the sphere, the perturbation potential decays as the inverse of the distance squared from the center of the sphere, as confirmed numerically when the source potential is due to either a point charge or a point dipole. [ABSTRACT FROM AUTHOR]

The propagation of compound plasmon-polariton (CPP) waves was investigated for the canonical boundary-value problem involving a metal film sandwiched between a homogeneous uniaxial dielectric material and a periodically nonhomogeneous isotropic dielectric material. Attention was focused upon exceptional CPP waves whose decay in the uniaxial dielectric material is governed by the product of a linear and an exponential function of distance from the uniaxial dielectric/metal interface. For physically realistic constitutive-parameter values, up to three exceptional CPP waves were found to exist, each with different propagation directions and with different wavenumbers, in each quadrant of the interface plane. The number of exceptional CPP waves, and their natures, were found to be sensitive to the period of the nonhomogeneous material, the thickness of the metal, as well as the constitutive properties of all three materials involved. [ABSTRACT FROM AUTHOR]

A systematic study of the degradation caused by electrical stress in Parylene-C columnar microfibrous thin films (μFTFs) was carried out to explore their suitability for applications in flexible electronics. The columnar μFTFs were fabricated by directing a collimated flux of Parylene-C monomers normally toward a planar substrate in a low-vacuum chamber. Metal-insulator-metal (MIM) capacitors incorporating Parylene-C columnar μFTFs were fabricated and electrically characterized to examine reliability and electrical-stress resistance. The measured leakage current in and capacitance of MIMs were studied as functions of constant-voltage stress (CVS) applied to the MIMs. Room-temperature leakage current in the MIMs before and after CVS was found to be space-charge limited. The space charge comprises defects introduced during fabrication, no new defects being induced by the CVS. Kohlrausch-Williams-Watts relaxation was exploited to understand transient leakage-current behavior, and characteristic times in the 3.5–3.9 s range and stretch factors in the 4.2–5.2 range were determined. These parameters suggest that carrier trapping at defects and their polarization orientation are related to space-charge formation. Furthermore, capacitance dependences on time and frequency were found to be good indicators of the CVS-induced degradation and stability. Charge buildup in the Parylene-C columnar μ-FTFs is accompanied by capacitance decrease with CVS duration. Extrapolation of the capacitance-decrease dependence on CVS duration enables predictions of reliability over extended periods. [ABSTRACT FROM AUTHOR]

Parylene-C microfibrous thin films ( \mu FTFs), grown using oblique-angle physicochemical vapor deposition, were examined for potential use as low-relative-permittivity (i.e., low- \kappa ) interlayer dielectrics in integrated circuits and, more importantly, flexible electronics. These films were characterized using capacitance–voltage–temperature (CVT) and current–voltage–temperature experiments at different temperatures (ranging from 298 to 420 K) and frequencies (ranging from 1 kHz to 1 MHz). Field emission scanning electron microscopy revealed the Parylene C \mu FTFs to be highly porous. Consequently, their \kappa values are at least 20% lower than those of bulk Parylene C. The dependences of \kappa on frequency and temperature suggest that molecular dipole oscillations are responsible for charge polarization in the \mu of \kappa in agreement with those obtained from CVT experiments, thus confirming our identification of PF as themajor responsiblemechanism and confirming the low- \kappa characteristic of microfibrous Parylene C. The ac current transport in the \mu , with s\in [{0.082,0.85}] increasing with temperature. AC conduction in the \mu $ FTFs is temperature-activated with an activation energy that decreases from 0.020 to 0.012 eV as frequency increases from 1 kHz to 1 MHz. [ABSTRACT FROM PUBLISHER]

• Thermal hysteresis surface-plasmon-polariton (SPP) wave propagation. • SPP-wave propagation possible over the entire thermal-hysteresis regime. • Phase speed higher on the cooling branch. • Attenuation rates higher on the heating branch. • Useful to sense if the temperature is increasing or decreasing. Propagation of surface-plasmon-polariton (SPP) waves guided by a metal/dielectric interface can be greatly affected by thermal hysteresis in the dielectric material. Calculations for the silver/vanadium-dioxide interface show that, while SPP-wave propagation is possible over the entire thermal-hysteresis regime 58 ° C * * , 72 ° C if the wavelength ≲ 1100 nm, at higher frequencies SPP-wave propagation is possible only in a low-temperature portion of the same regime. The phase speed is higher and the attenuation rates are lower on the cooling branch than on the heating branch, which may be used to sense whether the temperature is increasing or decreasing. [ABSTRACT FROM AUTHOR]

The absorption and extinction efficiencies of a sphere covered by InSb coating and illuminated by an incident plane wave in the terahertz gap were computed. Numerical results shows that these efficiencies, for some core materials and in some spectral regimes, can be reduced by adjusting the temperature. This, reduction of absorption and extinction by the InSb coating is not possible for air and metallic spheres, but it is possible for dielectric spheres. Furthermore, the InSb coating is more effective in absorption reduction for more dissipative dielectric materials, whereas it is more effective in extinction reduction for less dissipative dielectric materials. [ABSTRACT FROM AUTHOR]

Abstract: The prism-coupled excitation of Dyakonov–Tamm waves guided by the planar interface of a homogeneous, isotropic dielectric material and a periodically nonhomogeneous sculptured nematic thin film (SNTF) was investigated. The excitation of Dyakonov–Tamm waves was identified by correlating a high-absorptance band in the plots of absorptance vs. the incidence angle and the direction of propagation in the interface plane with the solutions of the underlying canonical boundary–value problem. Dyakonov–Tamm waves were found to have a much wider angular existence domain than Dyakonov waves, and broader absorptance peaks than both the Dyakonov and Tamm waves in the plots of absorptance vs. the incidence angle. [Copyright &y& Elsevier]

Abstract: We explored the effects of relative motion on the excitation of surface-plasmon-polariton (SPP) waves guided by the planar interface of a metal film and a dielectric slab, both materials being isotropic and homogeneous. Electromagnetic phasors in moving and non-moving reference frames were related directly using the corresponding Lorentz transformations. Our numerical studies revealed that, in the case of a uniformly moving dielectric slab, the angle of incidence for SPP-wave excitation is highly sensitive to (i) the ratio β of the speed of motion to speed of light in free space and (ii) the direction of motion. When the direction of motion is parallel to the plane of incidence, the SPP wave is excited by p-polarized (but not s-polarized) incident plane waves for low and moderate values of β, while at higher values of β the total reflection regime breaks down. When the direction of motion is perpendicular to the plane of incidence, the SPP wave is excited by p-polarized incident plane waves for low values of β, but s-polarized incident plane waves at moderate values of β, while at higher values of β the SPP wave is not excited. In the case of a uniformly moving metal film, the sensitivity to β and the direction of motion is less obvious. [Copyright &y& Elsevier]

The scope for negative-phase-velocity (NPV) propagation in a particulate composite material, based upon isotropic dielectric-magnetic constituent material phases which do not themselves support NPV propagation, is examined using the extended Bruggeman homogenization formalism. Unlike the conventional Bruggeman formalism, the extended formalism takes into account the dimensions of the constituent particles. Representative calculations show that increasing the particulate dimensions diminishes the scope for NPV propagation in the composite material. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 709–712, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21451. [ABSTRACT FROM AUTHOR]

The concept of the electromagnetic trinity comprising vacuum, anti-vacuum, and nihility is extended to a zone in the 4-D ℇr-μr phase space that was largely inaccessible until the recent emergence of negative-phase-velocity materials. Expressions for Fresnel coefficients are derived for the reflection of plane waves at the planar interface of vacuum and a homogeneous, isotropic, dielectric-magnetic medium with constitutive properties lying in that zone. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 265–270, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21323 [ABSTRACT FROM AUTHOR]

Electromagnetic band gap (EBG) structures of two different configurations implemented inside R120 rectangular waveguides (frequency range 10–15 GHz) are examined. The first configuration has a periodic, piecewise uniform variation of permittivity in the propagation direction. Two types of such one-dimensional (1D) EBG structures are analyzed, one with the unit cell comprising two dielectric layers, the other with three dielectric layers per unit cell. The second configuration is two-dimensional, with the unit cell along the propagation direction containing two sections, each of which is made of alternating pillars of two dielectric materials. The Bloch theorem is invoked for the ideal EBG structures, which are infinitely long in the propagation direction. The mode-matching method (MMM) is used for real 1D-EBG structures, which contain a finite number of unit cells, whereas a combination of the coupled-mode method (CMM) and the MMM is used for real 2D-EBG structures. Spectrums of the transmission coefficient of the fundamental mode for the 1D-EBG structures are computed and shown to compare favorably against experimental data. The effect of inserting a defect in 1D-EBG structures is demonstrated theoretically as well as experimentally. The band gaps computed for real and ideal 2D-EBG structures are compared as well. [ABSTRACT FROM AUTHOR]

Guided wave propagation in a Ku -band rectangular waveguide filled with a series of cells of dielectric materials in the Kronig-Penney morphology is examined. Allowed and forbidden bands in these ideal electromagnetic band-gap (EBG) filters are obtained for the TE z and TM z propagation modes by invoking the Floquet theorem. Real EBG structures, with a finite number of unit cells, are also studied using the scattering matrix technique. As the number of unit cells in a real structure increases, its transmission characteristics converge to those of its ideal analogue. [ABSTRACT FROM AUTHOR]

Two methods for oblique propagation in two dielectric examples of helicoidal bianisotropic mediums – chiral sculptured thin films and chiral smectic liquid crystals – are compared: (i) the series solution method, and (ii) the piecewise homogeneity approximation method. Both have to be numerically implemented, although only the former relies on an exact analytic solution of the frequency-domain Maxwell postulates. Convergence in the series solution method is investigated via calculations for a variety of planewave-illumination parameters and constitutive properties. Likewise, the maximum slice thickness for convergent results from the piecewise homogeneity approximation method is also studied. The computational efficiencies of both methods are compared. [Copyright &y& Elsevier]

The Bruggeman approach is implemented to homogenize a collection of identical, similarly oriented, electrically small, ellipsoidal particles with intensity-dependent refractive index that are dispersed randomly and homogeneously in an isotropic, linear, dielectric host material. The homogenized composite medium is assumed to be cubically nonlinear and anisotropic, in the simplest approximation. The anisotropy of nonlinearity may be considerably different from the anisotropy of the linearity. The possible enhancement of nonlinearity is also anisotropic, with the most desirable performance along the shortest principal axis of the ellipsoidal particles. [ABSTRACT FROM AUTHOR]

Although a monochromatic plane wave of a certain circular polarization state and wavelength may be almost completely reflected by a chiral sculptured thin film, we show here that information coded in rectangular pulses can still be transmitted across the film—provided the rise and fall times of the pulses are sufficiently small and the pulse widths are sufficiently large. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 28: 59–62, 2001. [ABSTRACT FROM AUTHOR]

The absorption of normally incident light by axially excited slabs of dielectric thin-film helicoidal bianisotropic media (TFHBMs) is shown to be polarization dependent, and the circular Bragg phenomenon turns out to saturate as the slab thickness increases beyond a certain value. A specific feature of absorption in the Bragg regime is reflected in the transmittances, which may be monitored for the automated production of TFHBMs. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 22: 243–247, 1999. [ABSTRACT FROM AUTHOR]

The optical response of a thin-film helicoidal bianisotropic medium (TFHBM) slab to a normally incident plane wave is shown to be affected by a substrate and a lid, both nondissipative. The theoretical transmissivity of the TFHBM changes with the incorporation of the substrate and the lid, as does the optical rotation. The apparent circular dichroism changes slightly in the Bragg regime, but the true circular dichroism does not appear to be greatly affected by the substrate and lid. These results are pertinent to experimental characterization of TFHBMs. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 20: 218–222, 1999. [ABSTRACT FROM AUTHOR]

The three-dimensional electric Green function for uniaxial dielectric media has been given by Chen (1973, 1983) Here we give the magnetic Green's function, whose form suggests that magnetic field formulations may be more tractable than electric field formulations. Using the electric and the magnetic Green's functions, canonical sources for the independent generation of the ordinary and the extraordinary fields are also obtaned. [ABSTRACT FROM AUTHOR]

Based on the Maxwell Garnett (MG) formalism for homogenizing particulate composite media, an incremental MG (IMG) formalism is developed. Whereas the MG formalism is suitable for dilute composite media, the IMG formalism is phenomenologically valid even for dense composite media because it homogenizes incrementally over a succession of several intermediate dilute composite media. IMG algorithms are presented for the simple dielectric-in-dielectric, as well as the complicated bianisotropic-in-bianisotropic composite media. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 17: 276–279, 1998. [ABSTRACT FROM AUTHOR]

Asymmetry in a regular dielectric photonic crystal of finite thickness created by periodically altering one of its two pupils results in the exhibition of diode-like passbands that can be switched on/off by injecting/removing a coherent atomic gas.The diode-like operation is accompanied by diffraction-enabled deflection of the transmitted wave, within a stop band of the gas-free structure. Alteration of the oscillator strength can be used to engineer the passband characteristics. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1248-1250, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27562 [ABSTRACT FROM AUTHOR]

One-dimensional (1D) magnetophotonic crystals (MPCs) can incorporate optical gyrotropy induced by a bias magnetic field, crystalline misalignment, and differential linear birefringence in a single photonic-crystal structure. A 1D MPC whose unit cell contains two layers—one magnetophotonic, the other not—displays intra-Brillouin-zone photonic bandgaps (PBGs) in the Brillouin diagram. While the optical gyrotropy makes the PBG bandwidths tunable by a bias magnetic field, the bicrystalline misalignment modifies and can even trump this magnetic tunability. Magnetic tunability is greatly affected by a proper selection of the two materials; e.g., a large birefringence ratio between the two layers can dramatically enhance the magnetic tunability of the MPC. We also expect our 1D MPCs to be useful for detecting magnetic fields. [ABSTRACT FROM AUTHOR]

Refraction of obliquely incident plane waves due to the interface of a vacuous half-space and a half-space occupied by a simply moving, nondissipative, isotropic dielectric-magnetic medium is considered, when the medium's velocity lies parallel to the interface and in the plane of incidence. Counterposition of the refracted wave vector and time-averaged Poynting vector occurs when the medium's velocity is sufficiently large in magnitude and makes an obtuse angle with the incident wave vector. The counterposition induced by relative motion occurs whether the refraction is negative or positive when the medium is at rest. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 874–876, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22250 [ABSTRACT FROM AUTHOR]

Excitation of Dyakonov surface waves guided by a plane wave incident on a columnar thin film (CTF) deposited on a surface-relief grating decorating a dielectric substrate was studied using the rigorous coupled-wave approach, when the grating plane, the plane of incidence, and the morphologically significant plane of the CTF are all different. The absorptance for a specific linear polarization state of the incident plane wave was plotted as a function of the polar angle of incidence, at a fixed azimuthal angle, and those absorptance peaks were identified that are independent of the thicknesses of the CTF and the dielectric substrate. The angular locations of these absorptance peaks were correlated with the solution of the canonical boundary-value problem for surface-wave propagation. Dyakonov surface waves can be excited in a wider range of directions in the interface plane by p-polarized illumination than by s-polarized illumination. When the incidence and the grating planes do not coincide, it is possible to excite Dyakonov surfaces for multiple values of the polar angle of incidence. [ABSTRACT FROM AUTHOR]

We report on a strategy for achieving negative phase velocity (NPV) in a homogenized composite medium (HCM) conceptualized using the Bruggeman formalism. The constituent material phases of the HCM do not support NPV propagation. The HCM and its constituent phases are isotropic dielectric-magnetic media; the real parts of their permittivities/permeabilities are negative-valued, whereas the real parts of their permeabilities/permittivities are positive-valued. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 313–315, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21155 [ABSTRACT FROM AUTHOR]

The capacitance of a parallel-plate capacitor made of a dielectric thin-film helicoidal bianisotropic medium (TFHBM) is estimated using the quasielectrostatic approximation. The structural handedness and the local biaxiality of the TFHBM do not matter for the chosen application, but the tilt angle does. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 21: 286–288, 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]

Dyadic Green functions for time-harmonic fields in a homogeneous, isotropic, dielectric–magnetic medium, moving with constant velocity, are derived by first implementing a simple transformation and then using the dyadic Green functions available for uniaxial dielectric–magnetic mediums. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1073–1074, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21604 [ABSTRACT FROM AUTHOR]

The derivation of a new condition for characterizing isotropic dielectric-magnetic materials exhibiting negative phase velocity, and the equivalence of that condition with previously derived conditions, are presented. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 315–316, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20127 [ABSTRACT FROM AUTHOR]

Examines an alternative approach for the derivation of the magnetic Green's dyadic for uniaxial dielectrics. Optic axis of uniaxial dielectric media; Isotropic relative permittivity.

With the use of rigorously derived expressions for the scattering response of an electrically small sphere embedded in a uniaxial dielectric-magnetic medium, the Bruggeman formalism is established for mixtures of isotropic dielectric-magnetic and uniaxial dielectric-magnetic media. [ABSTRACT FROM AUTHOR]

A distinction exists between negative phase velocity and negative refraction for linear isotropic dielectric-magnetic materials, active or passive. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1681, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25290 [ABSTRACT FROM AUTHOR]

Abstract: Columnar and chevronic thin films of GeSbSe chalcogenide glasses were grown by the oblique-angle-deposition technique. These thin films were found to exhibit dielectric anisotropy in the near-infrared regime. The retardance of any of the fabricated thin films was found to increase linearly with the thickness. Columnar thin films exhibited significantly lower retardance per unit thickness than chevronic thin films. The experimental results indicate the potential of these thin films for near-infrared polarizers. [Copyright &y& Elsevier]

Abstract: The Bergman–Milton bounds provide limits on the effective permittivity of a composite material comprising two isotropic dielectric materials. These provide tight bounds for composites arising from many conventional materials. We reconsider the Bergman–Milton bounds in light of the recent emergence of metamaterials, in which unconventional parameter regimes for relative permittivities are encountered. Specifically, it is demonstrated that: (a) for nondissipative materials the bounds may be unlimited if the constituent materials have relative permittivities of opposite signs; (b) for weakly dissipative materials characterized by relative permittivities with real parts of opposite signs, the bounds may be exceedingly large. [Copyright &y& Elsevier]

Abstract: The differential method (also called the C method) is applied to the diffraction of linearly polarized plane waves at a periodically corrugated boundary between vacuum and a linear, homogeneous, uniaxial, dielectric–magnetic medium characterized by hyperbolic dispersion equations. Numerical results for sinusoidal gratings are presented and compared with those obtained by means of the Rayleigh method, showing that both the differential method and the Rayleigh method can fail to give adequate results for gratings supporting an infinite number of refracted Floquet harmonics. [Copyright &y& Elsevier]

The canonical boundary-value problem for the propagation of compound plasmon–polariton (CPP) waves, guided by a symmetric structure comprising a metal film embedded in a uniaxial dielectric material, was formulated and solved. In addition to unexceptional CPP waves whose field strength, in the dielectric material, decays exponentially with distance from the nearest dielectric/metal interface, this structure can also guide exceptional CPP waves whose fields, in the dielectric material, decay as the product of a linear function and an exponential function of distance from the nearest dielectric/metal interface. An explicit solution for exceptional CPP-wave propagation was derived and spatial field profiles for exceptional CPP waves were computed. At most, two exceptional CPP waves were found to propagate in two different directions within each quadrant of the interfacial plane. • A metal/dielectric structure can guide exceptional compound plasmon-polariton waves • An explicit solution for exceptional propagation has been derived • At most, two exceptional CPP waves propagate in two different directions [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]