Search results for "polarization."
showing 10 items of 1842 documents
Communication modes in vector diffraction
2010
The communication modes, which mathematically correspond to singular value decomposition, have proven a useful concept in optical scalar-field diffraction, with applications in resolution studies, image synthesis, and wave propagation. For optical near-field geometries the communication modes have to be extended to electromagnetic field accounting for the polarization properties. In this paper we present the vector-valued communication modes method based on the rigorous electric-field diffraction integral. As a special case the transverse-electric scalar field modes are obtained. The intensity and polarization properties of the leading electromagnetic communication modes in near-field arran…
Stimulated quasiparticles in spin-split superconductors
2015
Under the terms of the Creative Commons Attribution License 3.0 (CC-BY).
Biorthonormal-basis method for the vector description of optical-fiber modes
1998
This paper gives the theoretical basis for the development of real vector modal methods to describe optical-fiber modes. To this end, the vector wave equations, which determine the electromagnetic fields, are written in terms of a pair of linear, nonself-adjoint operators, whose eigenvectors satisfy biorthogonality relations. The key of our method is to obtain a matrix representation of the vector wave equations in a basis that is defined by the modes of an auxiliary system. Our proposed technique can be applied to fibers with any profile, even those with a complex refractive index. An example is discussed to illustrate our approach.
Computation of the field diffracted by a local surface defect: application to tip–sample interaction in the photon scanning tunneling microscope
1996
We use a method based on the Fourier transform of the electromagnetic field to compute the field diffracted by a local deformation of a plane boundary surface. We give a complete development of each step of the technique. To show the interaction that exists between the probe of a near-field optical microscope and the observed sample, we use the model of a truncated cone-shaped tip above a rectangular surface defect. We compute the electrical intensity along a line located between the tip and the local surface defect. We show the influence of the polarization of the incident wave and the effect of the position of the tip with respect to the position of the surface defect.
Generation of even harmonics of sub-THz radiation in bulk GaAs in the presence of a static electric field
2007
The static electric field effects on nonlinear carrier dynamics in low-doped GaAs bulk under the influence of an intense sub-terahertz field are studied by a three-dimensional multivalleys Monte Carlo simulation. The conversion efficiency is calculated by using the appropriate Maxwell equation for the propagation of an electromagnetic wave along a given direction in the medium. Production of odd and even harmonics due to the nonlinearity of the velocity-field relation is investigated.
The electromagnetic group: Bosonic BRST charge
1990
Abstract We give an infinite-dimensional Lie group from which a group approach to quantization (GAQ) derives a Gupta-Bleuler-like quantization for the electromagnetic field. The incorporation into the group law of the gauge transformation properties of Aμ(x), Aμ(x) → Aμ(x) + ∂μφ, requires a non-conventional generator which is related to the BRST charge.
Optical Plasmonic Yagi-Uda Nano-Antennas Array for Energy Harvesting Applications
2020
Optical nanoantennas have been of great interest recently due to their ability to support a highly efficient, localized surface plasmon resonance and produce significantly enhanced and highly confined electromagnetic fields. The Yagi-Uda nanoantenna, an optical analogue of the well-established radiofrequency Yagi-Uda antenna, stands out by its efficient unidirectional light emission and enhancement. In this paper, the design of an optical plasmonic Yagi-Uda nanoantenna for energy harvesting application is proposed. The enhancement of the directivity is reached by means of an organization in array. The simulation results, carried out by 3D code CST Studio, show that the proposed nanoantenna …
A deep study of the high–energy transient sky
2021
This is an open access article. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds t…
First attempt of the measurement of the beam polarization at an accelerator with the optical electron polarimeter POLO
2005
The conventional methods for measuring the polarization of electron beams are either time consuming, invasive or accurate only to a few percent. We developped a method to measure electron beam polarization by observing the light emitted by argon atoms following their excitation by the impact of polarized electrons. The degree of circular polarization of the emitted fluorescence is directly related to the electron polarization. We tested the polarimeter on a test GaAs source available at the MAMI electron accelerator in Mainz, Germany. The polarimeter determines the polarization of a 50 keV electron beam decelerated to a few eV and interacting with an effusive argon gas jet. The resulting de…
Similarities and differences between crystal and enzyme environmental effects on the electron density of drug molecules
2021
Abstract The crystal interaction density is generally assumed to be a suitable measure of the polarization of a low‐molecular weight ligand inside an enzyme, but this approximation has seldomly been tested and has never been quantified before. In this study, we compare the crystal interaction density and the interaction electrostatic potential for a model compound of loxistatin acid (E64c) with those inside cathepsin B, in solution, and in vacuum. We apply QM/MM calculations and experimental quantum crystallography to show that the crystal interaction density is indeed very similar to the enzyme interaction density. Less than 0.1 e are shifted between these two environments in total. Howeve…