The problems under consideration are related to wave propagation in nonlinear dispersive media, characterised by higher-order nonlinear and higher-order dispersive effects. Particularly two problems — wave propagation in dilatant granular materials and wave propagation in shape-memory alloys — are studied. Model equations are KdVlike evolution equations in both cases. The types of solutions are...

Electromagnetic wave properties in metamaterials including electromagnetic band gap (EBG) structures have been widely investigated due to their inherent capabilities for developing novel devices in the fields of optics, microwave and antenna engineering. In reality, most of the materials are dispersive or frequency-dependent, on the other hand, it is important to investigate how the performance...

A new finite-difference time-domain (FDTD) algorithm is introduced to solve two dimensional (2D) transverse magnetic (TM) modes with a straight dispersive interface. Driven by the consideration of simplifying interface jump conditions, the auxiliary differential equation of the Debye constitution model is rewritten to form a new Debye–Maxwell TM system. Interface auxiliary differential equation...

key words: 1064 nm dispersive Raman spectroscopy, pigment analysis, traditional red artists’ colorants Raman spectra of red colorants were obtained in-situ using a dispersive Raman microscope equipped with a 1064 nm laser source and InGaAs array detector. By employing nearIR excitation, the fluorescence of organic colorants is significantly reduced compared to visible wavelengths. Spectra prese...

A three-dimensional (3-D) time-domain numerical scheme for simulation of ground penetrating radar (GPR) on dispersive and inhomogeneous soils with conductive loss is described. The finite-difference time-domain (FDTD) method is used to discretize the partial differential equations for time stepping of the electromagnetic fields. The soil dispersion is modeled by multiterm Lorentz and/or Debye m...

Nuclear magnetic resonance measurements of scale dependent dynamics in a random solid open-cell foam reveal a characteristic length scale for transport processes in this novel type of porous medium. These measurements and lattice Boltzmann simulations for a model foam structure indicate dynamical behavior analogous to lower porosity consolidated granular porous media, despite extremely high por...

Superluminal group velocities, defined as group velocities exceeding the speed of light in vacuum, c, have been theoretically predicted and experimentally observed in various types of dispersive media, such as passive and active Lorentzian media, one-dimensional photonic crystals, and undersized waveguides. Though the group velocity was found to be superluminal in these media, it has been sugge...

G. A. El,* A. Gammal, E. G. Khamis, R. A. Kraenkel, and A. M. Kamchatnov Department of Mathematical Sciences, Loughborough University, Loughborough LE11 3TU, United Kingdom Instituto de Física, Universidade de São Paulo, 05315-970, C.P.66318 São Paulo, Brazil Instituto de Fisica Teórica, Universidade Estadual Paulista, Rua Pamplona 145, 01405-900 São Paulo, Brazil Institute of Spectroscopy, Rus...

The arrival time of a light pulse at a point in space is defined using a time expectation integral over the Poynting vector. The delay between pulse arrival times at two distinct points is shown to consist of two parts: a spectral superposition of group delays (inverse of group velocity) and a delay due to spectral reshaping via absorption or amplification. The result provides a context wherein...

This first part of a two-part investigation is concerned with the effects of dispersion on the propagation characteristics of the scalar field associated with a highly localized pulsed-beam (PB) wave packet in a lossless homogeneous medium described by the generic wave-number profile k(v) 5 v/c(v), where c(v) is the frequency-dependent wave propagation speed. While comprehensive studies have be...