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Unusual reflection of electromagnetic radiation from a stack of graphene layers at oblique incidence  [PDF]
Yuliy V. Bludov,Nuno M. R. Peres,Mikhail I. Vasilevskiy
Physics , 2013, DOI: 10.1088/2040-8978/15/11/114004
Abstract: We study the interaction of electromagnetic (EM) radiation with single-layer graphene and a stack of parallel graphene sheets at arbitrary angles of incidence. It is found that the behavior is qualitatively different for transverse magnetic (or p-polarized) and transverse electric (or s-polarized) waves. In particular, the absorbance of single-layer graphene attains minimum (maximum) for p (s) polarization, at the angle of total internal reflection when the light comes from a medium with a higher dielectric constant. In the case of equal dielectric constants of the media above and beneath graphene, for grazing incidence graphene is almost 100% transparent to p-polarized waves and acts as a tunable mirror for the s-polarization. These effects are enhanced for the stack of graphene sheets, so the system can work as a broad band polarizer. It is shown further that a periodic stack of graphene layers has the properties of an one-dimensional photonic crystal, with gaps (or stop--bands) at certain frequencies. When an incident EM wave is reflected from this photonic crystal, the tunability of the graphene conductivity renders the possibility of controlling the gaps, and the structure can operate as a tunable spectral--selective mirror.
Design of a Dual-Band Sectoral Antenna for Hiperlan2 Application Using Double Layers of Metallic Electromagnetic Band Gap (M-EBG) Materials as a Superstrate  [PDF]
M. Hajj,R. Chantalat,B. Jecko
International Journal of Antennas and Propagation , 2009, DOI: 10.1155/2009/153850
Abstract: A novel design of a sectoral antenna that utilizes a double layer Metallic Electromagnetic Band Gap (M-EBG) as a superstrate for dual band directivity enhancement is presented in this paper. We obtain the different operating frequencies by adjusting the distance of the lower M-EBG layer from printed patch antenna and also the height between upper and lower M-EBG layers. This antenna operates according to a sectoral radiation pattern form presenting a half power beamwidth of at least 60°. The proposed structure presents more than 17 dB directivity enhancement at 5.25 GHz and 5.65 GHz as compared to those of a patch antenna with 9 dB directivity. The principle is explained and applied to a Hiperlan2 antenna.
Electromagnetic Radiation From The Accelerating Universe  [PDF]
James Timothy Struck
Physics , 2003,
Abstract: The acceleration of the expansion of the universe has been argued for by several research groups. If the universe is accelerating and if the universe or some part of the universe has a charge, then there may be electromagnetic radiation produced from the acceleration of the universe since accelerating charges produce electromagnetic radiation. This letter does a thought experiment to ask about the possible characteristics of the radiation from an accelerating universe. A value for the power, or rate of energy flow, of the universe's acceleration is calculated in this letter. A value of the power of the electromagnetic radiation emitted by the universe's acceleration is calculated to be P = 5.99 x 10 -82 Joule/sec or 5.99 x 10 -82 Watts. This value for the power assumes only the charge of an electron as the value for the charge; larger charges would produce much larger rates of energy flow. The letter then reveals what a characteristic of a charged, accelerating universe would be.
Ultra-Wideband Electromagnetic Radiation from GaAs Photoconductive Switches
Abstract,
Shi Wei
,Jia Wanli,and Ji Weili

半导体学报 , 2005,
Abstract: The experiment results of ultrawide band electromagnetic radiation with DC biased GaAs photoconductive semiconductor switch combining double ridge horn antenna triggered by high repeat frequency femto-second laser pulse are reported.The GaAs switches are insulated by solid multi-layer transparent dielectrics and the distance of two electrodes is 3mm.The electrode material of the switch is ohmic contact through alloy technics with definite proportion of Au/Ge/Ni.This switch and double ridge horn antenna are integrated and the receive antenna is connected with the test instrument.From receiving antenna,ultra fast electrical pulse of 200ps rise time and 500ps pulse width is obtained,the repetition rate of the pulse is about 82MHz and the frequency spectrum is in the range of 4.7MHz~14GHz.The radiation characteristic of the ultrafast electrical pulse is analyzed.
Influence of ions on relativistic double layers radiation in astrophysical plasmas
AM Ahadi,S Sobhanian
Iranian Journal of Physics Research , 2009,
Abstract: As double layers (DLs) are one of the most important acceleration mechanisms in space as well as in laboratory plasmas, they are studied from different points of view. In this paper, the emitted power and energy radiated from charged particles, accelerated in relativistic cosmic DLs are investigated. The effect of the presence of additional ions in a multi-species plasma, as a real example of astrophysical plasma, is also investigated. Considering the acceleration role of DLs, radiations from accelerated charged particles could be seen as a loss mechanism. These radiations are influenced directly by the additional ion species as well as their relative densities.
The Confinement of Electromagnetic Radiation of Nanoemitters in a Multilayered Microsphere with Left-Handed Layers  [PDF]
Gennadiy Burlak, Alfredo Díaz-de-Anda
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2010, DOI: 10.4236/jemaa.2010.212086
Abstract: The electromagnetic radiation of nanoemitters placed into a multilayered microsphere with dispersive left-handed (LH) layers included is studied numerically. It is found that in the frequency range where LH layers have a negative refraction index the field frequency spectrum consists of a series of narrow and well separated resonances. In the band of such peaks, the great part of the field energy is located in a LH layer and practically does not leave the microsphere.
Simulation of Coherent Synchrotron Radiation Emission from Rotating Relativistic Electron Layers  [PDF]
Bjoern S. Schmekel
Physics , 2004, DOI: 10.1103/PhysRevE.72.026410
Abstract: The electromagnetic radiation of a rotating relativistic electron layers is studied numerically using particle-in-cell simulation. The results of the simulation confirm all relevant scaling properties predicted by theoretical models. These models may turn out to be important for the understanding of the coherent synchrotron radiation (CSR) instability that may occur in systems as diverse as particle accelerators radio pulsars.
Electromagnetic and gravitational radiation from massless particles  [PDF]
D. V. Gal'tsov
Physics , 2015,
Abstract: We demonstrate that full description of both electromagnetic and gravitational radiation from massless particles lies outside the scope of classical theory. Synchrotron radiation from the hypothetical massless charge in quantum electrodynamics in external magnetic field has finite total power while the corresponding classical formula diverges in the massless limit. We argue that in both cases classical theory describes correctly only the low-frequency part of the spectra, while the total power diverges because of absence of the UV frequency cutoff. Failure of description of gravitational radiation from massless particles by classical General Relativity may be considered as another appeal for quantization of gravity apart from the problem of singularities.
Electromagnetic radiation from a laser wakefield accelerator  [PDF]
A. G. Khachatryan,F. A. van Goor,K. -J. Boller
Physics , 2008,
Abstract: Coherent and incoherent electromagnetic radiation emitted from a laser wakefield accelerator is calculated based on Lienard-Wiechert potentials. It is found that at wavelengths longer than the bunch length, the radiation is coherent. The coherent radiation, which typically lies in the infrared range, shows features that reveal details of the acceleration process and properties of the electron bunch, such as its duration, charge, energy, and offset with respect to the wakefield axis. The incoherent range of the spectrum, which extends to the X-ray frequency range, consists of rather broad peaks, which are caused by the acceleration.
Electromagnetic radiation from relativistic nuclear collisions  [PDF]
Charles Gale,Kevin L. Haglin
Physics , 2003,
Abstract: We review some of the results obtained in the study of the production of electromagnetic radiation in relativistic nuclear collisions. We concentrate on the emission of real photons and dileptons from the hot and dense strongly interacting phases of the reaction. We examine the contributions from the partonic sector, as well as those from the nonperturbative hadronic sector. We examine the current data, some of the predictions for future measurements, and comment on what has been learnt so far.
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