Search results for "FLE"
showing 10 items of 3517 documents
Multi-frequency super-scattering from sub-wavelength graphene-coated nanotubes
2019
A cylindrical multilayered structure with three coupled graphene shells is shown to behave as a dual-band super-scatterer at mid-infrared frequencies. Under the 2D plasmonic nature of graphene material, multiple scattering resonances are attained in the deep subwavelength regime using an isotropic material. In the proposed structure, we efficiently exploit the existing three plasmonic resonances in each scattering channel. These resonances are tailored by dispersion engineering, which is simply displayed through the Bohr model applied to the associated planar structure. For the super-scatterer design, it is essential that the resonances of multiple channels coincide in a single frequency. H…
Passive Polarimetric Imaging
2014
Passive electro-optical polarimetric imaging is a form of remote sensing in which the properties associated with electromagnetic field orientation are exploited as a means to discriminate between objects in an extended scene. The purpose of this chapter is to introduce some fundamental concepts in the science of imaging polarimetry. These concepts include the Stokes-Mueller description of polarized light, the physical mechanisms that contribute to polarimetric image contrast, a mathematical description of several polarimetric imaging systems, and an example target detection algorithm. Polarimetric image contrast is discussed in terms of reflected, emitted, and scattered light. Special empha…
Semilinear photorefractive oscillator with reflection gratings
2003
We present results of calculation of the steady-state output characteristics for a semilinear photorefractive oscillator pumped with two independent counterpropagating waves when the reflection grating is operative and compare them with measurements made with a BaTiO3:Co.
Specular reflection of spin-polarized electrons from the W(001) spin-filter crystal in a large range of scattering energies and angles
2015
Extending previous work on the imaging spin-filter technique based on electron diffraction from W(001) in the specular (00)-LEED (low-energy electron diffraction) spot, we studied the scattering-energy and angle-of-incidence landscape of spin sensitivity $S$ and reflectivity ${I/I}_{0}$. The setup includes a spin-polarized GaAs electron source and a rotatable delay-line detector for spatially resolving detection. We measured the intensity and spin asymmetry of the specularly reflected beam for energies between 14 and 37 eV and angles of incidence between ${30}^{\ensuremath{\circ}}$ and ${60}^{\ensuremath{\circ}}$. Resulting energy-angular landscapes show rather good agreement with theory [r…
Designing an x-ray baffle for stray-light reduction at the focal plane of the Wide Field Imager on board EDGE
2008
We exploited a ray-tracing Montecarlo code to investigate the effects of stray-light on the performances of the Wide Field Imager (FoV = 1.5 deg) on board the EDGE satellite. We found non negligible stray-light contamination up to ~ 8 deg off-axis angles. We discuss the benefits of a baffle in order to reduce this contamination, that would strongly affect the telescope sensitivity, and present two possible baffle designs based on results of simulations.
Unusual optical properties of the dense nonequilibrium plasmas
2005
A concise overview of new optical properties of dense nonequilibrium plasma formed on the solid state target boundary is given. In this chapter, we describe phenomena such as the third harmonic generation in the skin layer, collisionless electron heating in the high frequency skin-effect regime, absorption, and reflection and transmission of radiation by a plasma with anisotropic electron distribution.
Noise fiber lasers
2021
In this paper, we present a brief review of the noise operation mode of fiber lasers. These lasers were studied recently by collaborative group that includes researchers, professors, and Ph.D. students from the Centro de Investigaciones en Optica, A.C. (Leon, Guanajuato, Mexico) and from the Universidad de Valencia (Valencia, Spain). Meanwhile, the pioneer works in this topic important for understanding the physics behind fiber lasers’ operation and for practical applications were done with the active participation of Dr. Evgeny Kuzin from the Instituto Nacional de Astrofisica, Optica y Electronica (Puebla, Mexico) and Dr. Georgina Beltrán-Pérez from the Benemérita Universidad Autónoma de P…
Analytical description of lobster eye and similar multi-foil optics
2015
Analytical equations describing lobster eye optical parameters on dependence on its geometric parameters are presented. The paper partially gives review of main previously known results. At next, the paper gives new results discussing parameters, that were not included to previously published models but may be significant. The results are applicable for a Schmidt as well as for an Angel lobster eye and for some related multi-foil systems.
Asymmetric Conductivity of Strongly Correlated Compounds
2014
In this chapter, we show that the FC solutions for distribution function \(n_0(\mathbf{p})\) generate NFL behavior, and violate the particle-hole symmetry inherent in LFL. This, in turn, yields dramatic changes in transport properties of HF metals, particularly, the differential conductivity becomes asymmetric. As it is demonstrated in Sect. 3.1, Fermi quasiparticles can behave as Bose one. Such a state is viewed as possessing the supersymmetry (SUSY) that interchanges bosons and fermions eliminating the difference between them. In the case of asymmetrical conductivity it is the emerging SUSY that violates the time invariance symmetry. Thus, restoring one important symmetry, the FC state vi…
Lorenz–Haken instability in a laser with arbitrary mirrors reflectivity
2000
Abstract We study the Lorenz–Haken instability in a laser with arbitrary mirrors reflectivity R . In the limit of slow population difference we demonstrate that in order to observe the instability the reflectivity must exceed the critical value R c ≃0.5379, which coincides with that found recently for the multimode (Risken–Nummedal–Graham–Haken) instability. Several other differences with respect to the uniform field limit R →1 are presented.