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The plasmon excited at the surface of a thin metal film covering on a semi-infinite dielectric substrate is investigated in detailed. The surface plasmon dispersion relation is derived and presented by using the quantum hydrodynamic theory with taking into the quantum statistical and quantum diffraction effects. The effects of the thin metal film character r s and the dielectric constant ε 1 on the dispersion relations are shown and discussed, i.e., without and with quantum effects. The results show that increasing r s weakens the quantum effects while increasing ε 1 can enhance the quantum effects. In addition, the plasmon dispersion relation with quantum effects is also compared to a classical model. This simple structure proposed in the paper with quantum hydrodynamic theory can be used for yielding meaningful results for studying more complex systems related to surface plasmons. [ABSTRACT FROM AUTHOR]

Light transmission through slits array in a thin dielectric core layer sandwiched between two metallic cladding (MIM) is investigated using the finite-difference time-domain (FDTD) method. The dispersion relation of surface plasmon polariton (SPP) in the MIM structure is analyzed. The results show that SPP modes on the core layer act as a resonator-coupler, which helps to couple the resonance energy in the upper slit arrays to that in the lower slit arrays, and there is an enhanced transmission peak under appropriate resonance conditions. Coupling process is verified by the field profiles of the SPP modes calculated by FDTD method. Different MIM structures are designed to control the light transmission. [ABSTRACT FROM AUTHOR]

In this study, analysis of magnetized plasma photonic crystal (PPC) using 1-D modeling has been presented where effect of extra-ordinary modes of plasma on Photonic bandgaps (PBGs) is highlighted. The PPC characteristic has been studied in range of 1–140 GHz for the different structural parameters, plasma frequency, angle of incidence, collision frequency and applied magnetic field. In the PPC, presence of static magnetic field yields the extra-ordinary mode in plasma that introduces trapped oscillations in the PBGs. This has been comprehensively analyzed and presented in detail. A procedure has been developed to identify the frequency range of the trapped oscillation in PBG. Study also explores that the trapped oscillations can be shifted at any other position in a prescribed frequency band by having suitable parameters like electronics concentration, hybrid frequency and applied magnetic field etc. Presented work can be utilized to avoid the trapped oscillation which yields non linearity in PBG. [ABSTRACT FROM AUTHOR]

Abstract: The nonlinear effects in a metal due to the ponderomotive potential, which is induced by a steep spatial gradient in the electric field intensity, on the surface plasmon dispersion relation at a planar metal/dielectric interface are studied exactly. Previous studies invoked an approximation that amounts to keeping only the lowest order Kerr-like term in the metal dielectric constant. Comparing the exact result with the Kerr approximation reveals that the Kerr approximation often overestimates a cutoff frequency for the existence of surface waves and gives erroneous results in the range of frequencies below the overestimated cutoff and the real cutoff. Our result thus sheds light on the applicability of the Kerr approximation. Properly expanding the exact results recovers the standard linear results and the results starting with a Kerr-like approximation. [Copyright &y& Elsevier]

Abstract: We investigate the properties of Surface Plasmon Polaritons (SPPs) on two kinds of structures: metallic and dielectric gratings loaded on a metallic layer (MM grating and DM grating). The rigorous coupled wave analysis (RCWA) is used for all the simulation in this article. The characteristics of band gap, dispersion relation, reflectivity curves and resonant electric field distributions are comparative simulated and analyzed in MM and DM gratings. Compared with the sticky short-wavelength band edge and complicated surface electric field distributions of MM grating, it is found that the band gap edges of DM grating could be controlled flexibly and the surface fields are more smoothly, which can be used to facilitate the spectral tunability and tailor the optical response of DM structure. This work would provide help for understanding the intrinsic reason of the difference of SPPs in two kinds of structures and basis for choosing suitable structure (MM or DM) of SPPs devices aiming at different functions, especially for designing the dielectric loaded surface plasmon polaritions (DLSPPs) devices. [Copyright &y& Elsevier]

Abstract: The surface plasmon dispersion relation of a cylindrical metallic rod embedded in a Kerr nonlinear dielectric medium is studied using an integral approach. A formalism for the dispersion relation of the azimuthal symmetric mode is presented, in which an integral has to be treated numerically. We invoke an approximation based on weak nonlinearity. The results are in good agreement with numerical results obtained by requiring the fields to decay properly away from the rod. The formalism recovers the previous results of a metallic rod in a linear dielectric medium and a planar metallic/nonlinear interface as special cases. [Copyright &y& Elsevier]

Abstract: Both the bending and the diffusion of the refractive index are two basic issues concerning optical waveguides, but they are usually taken into account separately; in this paper we consider together these two important aspects deriving the dispersion equation for a set of curved waveguides which posses some layers with a diffused permittivity profile. First we introduce some different classes of curved and diffused regions for which an analytical solution of the admitted electromagnetic field can be found. Afterwards the modes and the dispersion equation for a waveguide formed by the interfacing of diffused and not diffused (e.g. with constant permittivity) layers are obtained by imposing the usual continuity conditions at the interfaces. An example is given of a curved diffused plasmonic waveguide, putting in evidence that its diffused region could be exploited in order to engineer the dispersion function of its fundamental mode. [Copyright &y& Elsevier]

Abstract: The theoretical analysis of propagation of guided waves in the multi-walled carbon nanotubes is presented within the framework of the classical electrodynamics. Electronic excitations of each wall of the system are modeled as an infinitesimally thin cylindrical layer of the π-electrons, whose dynamics are described by means of the fluid theory. General expressions of dispersion relations are obtained for the electromagnetic wave with the transverse magnetic and transverse electric modes, respectively, by solving Maxwell and fluid equations with appropriate boundary conditions. [Copyright &y& Elsevier]

Abstract: Propagation of surface plasma waves in a metallic single-walled carbon nanotube that either is encapsulated in a solid metallic channel or encapsulates a metallic nanowire are studied within the framework of the classical electrodynamics. The linearized hydrodynamic theory is used to describe the electronic excitations on the nanotube’s surface, while the dielectric function of dielectric media is modeled on the basis of the Drude approximation. It is shown that for all wavelengths, only the transverse magnetic wave with no angular dependence can propagate in these systems and the dispersion relations of this mode are obtained. [Copyright &y& Elsevier]

Abstract: A numerical dispersion relation is employed to analyze the linear and nonlinear optical effective refractive indices of 1-D finite periodic photonic bandgap structures. A Bragg reflector (BR) and a photonic crystal microcavity (PCMC) are examined by assuming that the high indexed layer of the two constituent layers possesses a nonlinear optical response. For the BR, the singularity of refractive index, appearing at bandgap edges in a Bloch index description, is removed. In the case of the PCMC, the optical responses at a defect mode and bandgap edges are properly described, thanks to the use of the numerical dispersion relation. This also allows us to quantitatively compare the Kerr nonlinearity observed at the defect mode and the bandgap edges. The efficiencies of the BR bandgap edge and the PCMC defect mode in achieving a given transmission change are compared by calculating the required nonlinear optical refractive index change. The PCMC defect mode is found to be 1.5 times and twice more efficient than the BR bandgap edge in 20 and 10dB transmission modulation, respectively. [Copyright &y& Elsevier]

Abstract: We show theoretically that the upper and lower cutoff frequencies of the guided band in a 2D photonic crystal coupled-cavity waveguide can be controlled independently or synchronously by changing two configuration parameters of the waveguide simultaneously. The independent control range for the lower and upper cutoff frequencies can be as large as 68.6% and 67.9% of photonic band gap, respectively. The two cutoff frequencies can also be tuned in the same direction over equal distances up to 25.7% of photonic band gap. These results offer an efficient way for designing the various dispersion relations for photonic crystal waveguides. [Copyright &y& Elsevier]

Abstract: Shortcomings of diffusion theory when applied to turbid media such as biological tissue makes the development of more accurate equations desirable. Several authors developed telegrapher’s equations in the well known P 1 approximation. The method used in this paper is different: it is based on the asymptotic evaluation of the solutions of the equation of radiative transport with respect to place and time for all values of the albedo. Various coefficients for the telegrapher’s equations were derived, restricted to the case of isotropic scattering, and their properties are discussed. A correct diffusion coefficient for the stationary case could be obtained. However, this solution did not lead to the correct phase velocity. Correct phase velocities in combination with a correct diffusion coefficient were found for a dispersion relation that corresponds with anisotropic Henyey–Greenstein scattering with g =0.22. It provides a time-dependent description of the fluence rate with validity for all values of the albedo. [Copyright &y& Elsevier]

We show that the general dispersion relation of a finite-length, one-dimensional, periodic photonic band-gap structure can be extended, by using the approach of the effective index of refraction and the Bloch vector, to yield an explicit relation between the real and imaginary components of an optical field emerging from such a structure. In consequence, by means of this Kramers–Kro¨nig-like relation, the recovery of the effective index can be obtained with a good approximation directly from transmissivity without involving any numerical integration algorithm. The expression for a two-layer, step-index-profile quarter-wave stack, derived in the case of TE polarisation, is described in details. Some numerical results are given and discussed. The performance of the established relation as used for index recovery is evaluated. [Copyright &y& Elsevier]

Modal properties of a hollow optical fiber are investigated in terms of dispersion equations, propagation constants and field profiles, by using both scalar approximation and exact vectorial analysis. The modes are seen to exhibit “nearly degenerate” groups satisfying approximately the same dispersion relations. Typical hollow fiber components have been considered as example cases for numerical evaluation. The analysis provides an insight of the modal characteristics of this class of fibers, and should be useful as a ready tool to define design parameters for realizing this fiber based in-line components, e.g., mode converter, core mode blocker, etc., and more importantly to explore new possibilities with this fiber. [Copyright &y& Elsevier]

Abstract: In this letter, dispersion properties of low-frequency electrostatic waves in multi-wall fullerene (the first layer is C 60molecule) are investigated. It is assumed that multi-wall fullerene is charged due to the field emission, and hence the multi-wall fullerene can be regarded as charged dust spheres surrounded by degenerate electrons and ions. We obtain the dispersion relation for the low-frequency electrostatic oscillations in the multi-wall fullerene by using the quantum hydrodynamic model in conjunction with the Poisson equation. [Copyright &y& Elsevier]

Abstract: We develop a theory of plasmon excitations in a metallic nanotube with a nonconcentric core using the plasmon hybridization method. We apply the two-center cylindrical coordinate system for mathematical convenience and find an explicit form of the dispersion relation for surface plasmons, in terms of interaction between the bare plasmon modes of the individual surfaces of the nanotubes. We present numerical result displaying the effect of the offset distant d of the inner core from the nanotube center, when there is no angular momentum transfer, i.e., . For large offsets, the plasmon shifts is strong, but weak for small offset. [Copyright &y& Elsevier]

In a recent article [R. P. Dwivedi, H.-I. Lee, O. Beom-Hoan, E.-H. Lee, Opt. Commun, 283 (2010) 4085], E.-H. Lee et al. studied the mechanism of light wave propagation through non-metallic nanowires of sub-diffraction dimension and presented the general expressions of the dispersions relations of TE and TM modes, respectively. Here we show that the system generally disallows the separation of the TE and TM modes, except for the case of modes with no angular dependence. [ABSTRACT FROM AUTHOR]

Abstract: In this letter, dispersion properties of low-frequency electrostatic waves in a C 60 molecule are investigated. It is assumed that C 60 molecule is charged due to the field emission, and hence the C 60 molecule can be regarded as charged dust spheres surrounded by degenerate electrons and ions. We obtain the dispersion relation for the low-frequency electrostatic oscillations in the C 60 molecule by using the quantum hydrodynamic model in conjunction with the Poisson equation. [Copyright &y& Elsevier]