Home OALib Journal OALib PrePrints Submit Ranking News My Lib FAQ About Us Follow Us+
 Title Keywords Abstract Author All
Search Results: 1 - 10 of 100 matches for " "
 Page 1 /100 Display every page 5 10 20 Item
 Physics , 2012, DOI: 10.1103/PhysRevA.87.013404 Abstract: An analytic description of laser-assisted electron-atom scattering (LAES) in an elliptically polarized field is presented using time-dependent effective range (TDER) theory to treat both electron-laser and electron-atom interactions non-perturbatively. Closed-form formulas describing plateau features in LAES spectra are derived quantum mechanically in the low-frequency limit. These formulas provide an analytic explanation for key features of the LAES differential cross section. For the low-energy region of the LAES spectrum, our result generalizes the Kroll-Watson formula to the case of elliptic polarization. For the high-energy (rescattering) plateau in the LAES spectrum, our result generalizes prior results for a linearly polarized field valid for the high-energy end of the rescattering plateau [A.\,V. Flegel \textit{et al.}, J. Phys. B \textbf{42}, 241002 (2009)] and confirms the factorization of the LAES cross section into three factors: two field-free elastic electron-atom scattering cross sections (with laser-modified momenta) and a laser field-dependent factor (insensitive to the scattering potential) describing the laser-driven motion of the electron in the elliptically polarized field. We present also approximate analytic expressions for the exact TDER LAES amplitude that are valid over the entire rescattering plateau and reduce to the three-factor form in the plateau cutoff region. The theory is illustrated for the cases of $e$-H scattering in a CO$_2$-laser field and $e$-F scattering in a mid-infrared laser field of wavelength $\lambda=3.5\,\mu$m, for which the analytic results are shown to be in good agreement with exact numerical TDER results.
 Physics , 2015, DOI: 10.1016/j.physd.2013.05.008 Abstract: We study pattern formation on the plane transverse to propagation direction, in a ring cavity filled with a Kerr-like medium, subject to an elliptically polarized incoming field, by means of two coupled Lugiato-Lefever equations. We consider a wide range of possible values for the coupling parameter between different polarizations, *B*, as may happen in composite materials. Positive and also negative refraction index materials are considered. Examples of marginal instability diagrams are shown. It is shown that, within the model, instabilities cannot be of codimension higher than 3. A method for finding parameters for which codimension 2 or 3 takes place is given. The method allows us to choose parameters for which unstable wavenumbers fulfill different relations. Numerical integration results where different instabilities coexist and compete are shown.
 Physics , 2007, Abstract: A computational algorithm for the exact equations representing the scattering coefficients of an infinite grating of insulating dielectric circular cylinders associated with obliquely incident vertically polarized plane electromagnetic waves is generated by matrix methods, and the solution for the scattering coefficients is acquired by a matrix inversion procedure.
 O. El Gawhary Physics , 2005, Abstract: We study the free-propagation features of an optical field endowed with a non-uniform polarization pattern with elliptical symmetry. The fields derived in this way are called Elliptically Symmetric Polarized Beams (ESPB for short). Some properties of these fields are analysed. Moreover, it is shown how it is possible to obtain such light beams by applying the results to Bessel-Gauss beams.
 Journal of Microwaves, Optoelectronics and Electromagnetic Applications , 2012, DOI: 10.1590/S2179-10742012000100018 Abstract: this paper describes a model for the analysis of multilay-ered chiral structures containing planar electric and magnetic scattering elements of arbitrary shape, illuminated by an elliptically polarized plane wave. the particular case of a single chiral layer is analyzed and the scattering matrices for single and dual electric and/or magnetic dipole distributions are derived in an original way. as an application, the polarimetric response of a short electric or magnetic dipole is directly obtained from their scattering matrix.
 Physics , 2007, DOI: 10.1119/1.2870269 Abstract: We apply the Poynting theorem to the scattering of monochromatic electromagnetic planes waves with normal incidence to the interface of two different media. We write this energy conservation theorem to introduce a natural definition of the scattering matrix S. For the dielectric-dielectric interface the balance equation lead us to the energy flux conservation which express one of the properties of S: it is a unitary matrix. For the dielectric-conductor interface the scattering matrix is no longer unitary due to the presence of losses at the conductor. However, the dissipative term appearing in the Poynting theorem can be interpreted as a single absorbing mode at the conductor such that a whole S, satisfying flux conservation and containing this absorbing mode, can be defined. This is a simplest version of a model introduced in the current literature to describe losses in more complex systems.
 Physics , 2007, Abstract: In this article, we present the asymptotic solution for the matrix system of equations representing the multiple scattering coefficients of an infinite grating of insulating dielectric circular cylinders associated with vertically polarized obliquely incident plane electromagnetic waves.
 Physics , 2008, DOI: 10.1364/OE.16.020869 Abstract: We study the no reflection condition for a planar boundary between vacuum and an isotropic chiral medium. In general chiral media, elliptically polarized waves incident at a particular angle satisfy the no reflection condition. When the wave impedance and wavenumber of the chiral medium are equal to the corresponding parameters of vacuum, one of the circularly polarized waves is transmitted to the medium without reflection or refraction for all angles of incidence. We propose a circular polarizing beam splitter as a simple application of the no reflection effect.
 M. A. Ellabban Physics , 2008, Abstract: We present a detailed experimental investigation on polarization-isotropic and polarization-anisotropic holographic scattering in lithium niobate crystal doped with iron when recording parasitic gratings with an ordinary polarized pump beam. The kinetics of both types of scattering during the whole process of recording is studied. Holographic scattering is presented as a simple technique to monitor the energy transfer between beams of different polarization. Moreover, the spectral and the angular dependence of the transmitted intensity of the crystal during the reconstruction of the auto-generated parasitic gratings are measured.
 Journal of Applied Mathematics , 2012, DOI: 10.1155/2012/371729 Abstract: “An exact matrix conformation model” associated with the equations describing the exact behavior of the Fourier-Bessel multiple scattering coefficients of the diffraction grating consisting of an infinite number of infinitely long parallel penetrable circular cylinders, corresponding to the obliquely incident transverse-magnetic plane waves in “Twersky-Wait-Kavaklıoğlu representation,” originally excogitated in (Kavaklıoğlu, 2000), is acquired, and the exact solution for “the Fourier-Bessel multiple scattering coefficients of the diffraction grating at oblique incidence” is obtained by a matrix inversion procedure.
 Page 1 /100 Display every page 5 10 20 Item