Publications

2010
Kalmykov SY, Reed SA, Yi SA, Beck A, Lifschitz AF, Davoine X, Lefebvre E, Khudik V, Shvets G, Dong P, et al. Laser wakefield electron acceleration on Texas petawatt facility: Towards multi-GeV electron energy in a single self-guided stage. High Energy Density Physics [Internet]. 2010;6 :200 - 206. Publisher's Version
Korobkin D, III BN, Fietz C, Jegenyes N, Ferro G, Shvets G. Measurements of the negative refractive index of sub-diffraction waves propagating in an indefinite permittivity medium. Opt. Express [Internet]. 2010;18 :22734–22746. Publisher's Version
Dong P, Reed SA, Yi SA, Kalmykov SY, Shvets G, Downer MC, Matlis NH, Leemans WP, McGuffey C, Bulanov SS, et al. Visualization of plasma bubble accelerators using Frequency-Domain Shadowgraphy. High Energy Density Physics [Internet]. 2010;6 :153 - 156. Publisher's VersionAbstract

We report on generation of relativistic electron beams in the wake of a relativistically intense laser pulse traversing a 1.7 mm long atmospheric density helium gas jet. The plasma wake structure is recovered using a Frequency-Domain Holography (FDH) and Frequency-Domain Shadowgraphy (FDS). As the gas density changes, the accelerated electron beams show variations in cross-section area, divergence, total charge, and peak energy. FDH phase reconstruction shows discontinuities and large phase jumps due to plasma electrons blown out by the pump pulse, probe pulse refraction, and nonlinear propagation in plasma. However, FDS amplitude reconstruction shows bright spots that yield information about bubble formation and evolution.

2009
Kalmykov S, Yi SA, Khudik V, Shvets G. Electron Self-Injection and Trapping into an Evolving Plasma Bubble. Phys. Rev. Lett. [Internet]. 2009;103 :135004. Publisher's Version
III BN, Korobkin D, Fietz C, Carole D, Ferro G, Shvets G. Critically coupled surface phonon-polariton excitation in silicon carbide. Opt. Lett. [Internet]. 2009;34 :2667–2669. Publisher's VersionAbstract
We observe critical coupling to surface phonon-polaritons in silicon carbide by attenuated total reflection of mid-IR radiation. Reflectance measurements demonstrate critical coupling by a double scan of wavelength and incidence angle. Critical coupling occurs when prism coupling loss is equal to losses in silicon carbide and the substrate, resulting in maximal electric field enhancement.
Avitzour Y, Urzhumov YA, Shvets G. Wide-angle infrared absorber based on a negative-index plasmonic metamaterial. Phys. Rev. B [Internet]. 2009;79 :045131. Publisher's Version
Kalmykov S, Yi AS, Shvets G. All-optical control of nonlinear focusing of laser beams in plasma beat wave accelerator. Plasma Physics and Controlled Fusion [Internet]. 2009;51 :024011. Publisher's VersionAbstract
Nonlinear focusing of a bi-color laser in plasma can be controlled by varying the difference frequency Ω. The driven electron density perturbation forms a co-moving periodic focusing (de-focusing) channel if Ω is below (above) the electron Langmuir frequency ω p . Hence, the beam focusing is enhanced for Ω < ω p and is suppressed otherwise. In particular, a catastrophic relativistic self-focusing of a high-power laser beam can be prevented all-optically by a second, much weaker, co-propagating beam shifted in frequency by Ω > ω p . A bi-envelope equation describing the early stage of the mutual de-focusing is derived and analyzed. Later stages, characterized by a well-developed electromagnetic cascade, are investigated numerically. Stable propagation of the over-critical laser pulse over several Rayleigh lengths is predicted. The non-resonant plasma beat wave (Ω ≠ ω p ) can accelerate pre-injected electrons above 100 MeV with low energy spread.
Shvets G, Polomarov O, Khudik V, Siemon C, Kaganovich I. Nonlinear evolution of the Weibel instability of relativistic electron beams. Physics of Plasmas [Internet]. 2009;16 :056303. Publisher's Version
Zhang X, Davanço M, Urzhumov Y, Shvets G, Forrest SR. A subwavelength near-infrared negative index material. Applied Physics Letters [Internet]. 2009;94 :131107. Publisher's Version
Shvets G, Trendafilov S, Kopp VI, Neugroschl D, Genack AZ. Polarization properties of chiral fiber gratings. Journal of Optics A: Pure and Applied Optics [Internet]. 2009;11 :074007. Publisher's VersionAbstract
Recent experiments (Kopp et al 2007 J. Opt. Soc. Am. B 24 A48) have demonstrated that the polarization sensitivity of chiral fiber gratings depends strongly on the grating symmetry: double-helix fibers are polarization sensitive while single-helix fibers are not. A coupled-mode perturbation theory is developed and used to explain the polarization properties of chiral fiber gratings. Features of the transmission spectrum such as multiple dips in the spectrum and circular dichroism are also derived and attributed to chiral Bragg scattering of the core modes into the cladding modes of the fiber.
2008
Avitzour Y, Shvets G. Manipulating Electromagnetic Waves in Magnetized Plasmas: Compression, Frequency Shifting, and Release. Phys. Rev. Lett. [Internet]. 2008;100 :065006. Publisher's Version
Shvets G. Photonics: Metamaterials add an extra dimension. Nat Mater [Internet]. 2008;7 (1) :7 - 8. Publisher's Version
Karmakar A, Kumar N, Shvets G, Polomarov O, Pukhov A. Collision-Driven Negative-Energy Waves and the Weibel Instability of a Relativistic Electron Beam in a Quasineutral Plasma. Phys. Rev. Lett. [Internet]. 2008;101 :255001. Publisher's Version
Bianucci P, Fietz CR, Robertson JW, Shvets G, Shih C-K. Observation of simultaneous fast and slow light. Phys. Rev. A [Internet]. 2008;77 :053816. Publisher's Version
Kalmykov YS, Yi AS, Shvets G. All-optical suppression of relativistic self-focusing of laser beams in plasmas. Phys. Rev. E [Internet]. 2008;78 :057401. Publisher's Version
Polomarov O, Kaganovich I, Shvets G. Merging of Super-Alfvénic Current Filaments during Collisionless Weibel Instability of Relativistic Electron Beams. Phys. Rev. Lett. [Internet]. 2008;101 :175001. Publisher's Version
Urzhumov YA, Shvets G. Optical magnetism and negative refraction in plasmonic metamaterials. Solid State Communications [Internet]. 2008;146 :208 - 220. Publisher's VersionAbstract
In this review we describe the challenges and opportunities for creating magnetically active metamaterials in the optical part of the spectrum. The emphasis is on the sub-wavelength periodic metamaterials whose unit cell is much smaller than the optical wavelength. The conceptual differences between microwave and optical metamaterials are demonstrated. We also describe several theoretical techniques used for calculating the effective parameters of plasmonic metamaterials: the effective dielectric permittivity ϵ eff ( ω ) and magnetic permeability μ eff ( ω ) . Several examples of negative permittivity and negative permeability plasmonic metamaterials are used to illustrate the theory.
Zhang X, Davanco M, Urzhumov Y, Shvets G, Forrest SR. From Scattering Parameters to Snell's Law: A Subwavelength Near-Infrared Negative-Index Metamaterial. Phys. Rev. Lett. [Internet]. 2008;101 :267401. Publisher's Version
Shapiro MA, Samokhvalova KR, Sirigiri JR, Temkin RJ, Shvets G. Simulation of the bulk and surface modes supported by a diamond lattice of metal wires. Journal of Applied Physics [Internet]. 2008;104 :103107. Publisher's Version
Maksimchuk A, Reed S, Bulanov SS, Chvykov V, Kalintchenko G, Matsuoka T, McGuffey C, Mourou G, Naumova N, Nees J, et al. Studies of laser wakefield structures and electron acceleration in underdense plasmas. Physics of Plasmas [Internet]. 2008;15 :056703. Publisher's Version

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