III BN, Korobkin D, Fietz C, Carole D, Ferro G, Shvets G.
Critically coupled surface phonon-polariton excitation in silicon carbide. Opt. Lett. [Internet]. 34 :2667–2669.
Publisher's VersionAbstractWe 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.
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]. 51 :024011.
Publisher's VersionAbstractNonlinear 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]. 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]. 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]. 11 :074007.
Publisher's VersionAbstractRecent 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.