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All-optical and dynamic manipulation of surface plasmon polaritons by tailoring the polarization state of incident light
摘要： A hybridly polarized vector beam comprising linear, elliptical, and circular polarizations at the beam cross-section is investigated for the manipulation of surface plasmon polaritons (SPPs). Unlike the well-known radially- or azimuthally-polarized beam that only includes linear polarization, this hybridly polarized beam provides increased optical degrees of freedom, which assist in controlling the excitation, orientation, and distribution of the focused SPPs excited in a high-numerical-aperture microscopic configuration. Many fascinating SPP patterns can be easily obtained, such as sharp peaks, multi-foci, donuts, and dark polygons. Those novel properties might be of great value in applications such as plasmonic tweezers.
关键词： electromagnetic wave propagation,polarization,interference,optical properties of surfaces
更新于2025-09-23 15:19:57
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Nonlinear Fiber Optics || Pulse propagation in fibers
摘要： For an understanding of the nonlinear phenomena in optical ?bers, it is necessary to consider the theory of electromagnetic wave propagation in dispersive nonlinear media. The objective of this chapter is to obtain a basic equation that governs propagation of optical pulses in single-mode ?bers. Section 2.1 introduces Maxwell’s equations and important concepts such as the linear and nonlinear parts of the induced polarization and the frequency-dependent dielectric constant. The concept of ?ber modes is introduced in Section 2.2 where the single-mode condition is also discussed. Section 2.3 considers the theory of pulse propagation in nonlinear dispersive media in the slowly varying envelope approximation with the assumption that the spectral width of the pulse is much smaller than the frequency of the incident radiation. The numerical methods used to solve the resulting propagation equation are discussed in Section 2.4.
关键词： electromagnetic wave propagation,dispersive nonlinear media,numerical methods,nonlinear phenomena,optical fibers,single-mode fibers,fiber modes,pulse propagation,dielectric constant,induced polarization,Maxwell’s equations
更新于2025-09-12 10:27:22
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-point dependent electromagnetic beam propagation in a graphenelike triangular metallic photonic structure
摘要： We study the electromagnetic wave propagation in a graphenelike triangular metallic photonic structure and show that, associated to trigonally warped Dirac cones, the transport properties resulting from an incident beam at the armchair edge display drastically different behaviors as compared to the results obtained for other analogous systems. Namely, at K point, only the center beam associated to the lower Dirac cone and the side beams to the upper cone and, at K (cid:2) point, only the center beam associated to the lower cone display signi?cant intensities. The other expected beams are all strongly inhibited. This can be related to the metallic nature of the structure, where the low frequency electromagnetic bands are formed by local resonance modes con?ned inside the structural units. A propagating wave should follow the structure local patterns that govern its ?eld distribution, whose symmetry properties determine its excitation by an incident wave.
关键词： graphenelike triangular metallic photonic structure,trigonal warping,armchair edge,electromagnetic wave propagation,Dirac cones
更新于2025-09-12 10:27:22
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Analysis of Electromagnetic Wave Propagation in Variable Magnetized Plasma via Polynomial Chaos Expansion
摘要： A three-dimensional stochastic FDTD algorithm is developed and applied to electromagnetic wave propagation in collisional magnetized plasma characterized by a variable electron density, collision frequency, and background magnetic ?eld. The proposed stochastic model is based on the expansion of the random / variable time-domain electric and magnetic ?elds in terms of orthogonal polynomials in independent random variables representative of the variable ionospheric content. Electromagnetic wave propagation in magnetized plasma having low variability (small deviations) and also high variability (large deviations) of the electron density, collision frequency, and background magnetic ?eld is studied. The stochastic algorithm is validated against brute-force Monte Carlo results. The algorithm is considerably more computationally ef?cient than Monte Carlo. When applied to electromagnetic wave propagation in the ionosphere, the variability of the Earth’s magnetic ?eld and ionospheric parameters can be accounted for due to naturally varying space weather conditions and day-to-day variations, measurement errors, etc. Although only electrons are considered here, positive and negative ions may be accommodated in a straight-forward manner.
关键词： ?nite-difference time-domain (FDTD),electromagnetic wave propagation,ionosphere,polynomial chaos,uncertainty,collisional magnetized cold plasma
更新于2025-09-11 14:15:04
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Propagation of Electromagnetic Waves through an Invisible Gradient-Index Lens with Negative Refractive Index
摘要： A radially inhomogeneous (gradient-index) lens made of material with a negative refractive index, invisible from the viewpoint of geometrical optics, is proposed and designed. The design includes derivation and solution of an equation for determining the refractive index profile, as well as derivation of an expression allowing calculation of the ray trajectories in the lens. Propagation of a plane wave through a cylindrical modification of the proposed lens both for the case of E-polarization and for the case of H-polarization is analyzed numerically using the hybrid projection method. The results obtained for the RCS of the lens are compared to the similar performance of a positive-index lens described in the previous publications.
关键词： numerical methods,RCS,geometrical optics,invisible lens,Electromagnetic wave propagation,negative refractive index,gradient-index lens
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE International Conference on Intelligent Transportation Systems (ITSC) - Maui, HI, USA (2018.11.4-2018.11.7)] 2018 21st International Conference on Intelligent Transportation Systems (ITSC) - Automotive Radar Multipath Propagation in Uncertain Environments
摘要： Future use of high-resolution near range radar sensors for vehicle environment perception is facing challenges in terms of detection and correct assignment of multipath reflections (false-positives) from surfaces and obstacles. This paper presents a novel geometric model to determine the relative positions from surrounding targets and reflection surfaces assuming that every object moves on a circular path to a mutual center. Principles of electromagnetic wave propagation under consideration of incident wave angles at potential reflection surfaces are described. Radar measurements illuminating an experimental target and a highway barrier as reflection surface, which reproducibly generates several multipath reflections, were carried out in a deterministic test environment and validate our presented methods. The installation of absorption material at intense reflection areas was conducted as countermeasure to reduce the intensity of false-positive detections. Furthermore, a realistic urban driving scenario using a real vehicle as target object and a building wall was reconstructed to proof field relevance.
关键词： electromagnetic wave propagation,false-positive detections,multipath propagation,Automotive radar,geometric model
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - EM wave propagation experiment at e band and d band for 5G wireless systems: preliminary results
摘要： Preliminary results on an electromagnetic wave propagation experiment at E and D band are presented. The research activity is collaboration between Politecnico di Milano and the Huawei European Microwave Centre in Milan, which has recently installed short (325 m) terrestrial links operating at 73, 83, 148 and 156 GHz and connecting two buildings in the university main campus. Received power data are processed to identify and isolate rain events and quantify the fade induced by precipitation, AR. Moreover, AR is estimated taking advantage of ancillary data collected by a laser-based disdrometer collocated with the link transceivers. Preliminary results definitely point out the higher prediction accuracy achieved by exploiting the information on the rain drop size provided by the disdrometer.
关键词： Electromagnetic wave propagation,5G mobile networks,terrestrial links,measurement
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Statistics of Rain Attenuation in Prague, Empirical Data and Numerical Predictions
摘要： Attenuation of electromagnetic waves in microwave bands is determined experimentally via measurement of received signal variations on terrestrial radio links operating in three frequency bands around 58, 94 and 122 GHz. The measured time series of attenuation are processed to obtain long-term cumulative distributions of attenuation due to hydrometeors. The obtained empirical distributions are compared with the ones predicted using the model of the Recommendation ITU-R P.530. For a given time percentages, the predicted attenuation levels exceeded are apparently lower than the levels of empirical distributions. A power-law relationship between attenuation and rain intensity is obtained by a least square approximation of measured simultaneous rain intensity and rain attenuation. The results are discussed and compared with the numerical predictions.
关键词： electromagnetic wave propagation,atmospheric hydrometeors,rain attenuation
更新于2025-09-04 15:30:14