Encontrados 12 documentos, a visualizar página 1 de 2
Stable dark solitons in PT-symmetric dual-core waveguides
Bludov, Yuliy V.; Konotop, Vladimir V.; Malomed, B. A.We construct dark solitons in the recently introduced model of the nonlinear dual-core coupler with the mutually balanced gain and loss applied to the two cores,which is a realization of parity-time symmetry in nonlinear optics. The main issue is stability of the dark solitons. The modulational stability of the continuous-wave background, which supports the dark solitons, is studied analytically, and the full s...
Enhancing the absorption of graphene in the terahertz range
Peres, N. M. R.; Bludov, Yuliy V.We study graphene on a photonic crystal operating in the terahertz (THz) spectral range. We show that the absorption of graphene becomes a modulated function of frequency and can be enhanced by more than three times at specific frequency values, depending on the parameters of the system. The problem of a semi-infinite photonic crystal is also solved.
A primer on surface plasmon-polaritons in graphene
Bludov, Yuliy V.; Ferreira, Aires; Peres, N. M. R.; Vasilevskiy, MikhailWe discuss the properties of surface plasmons-polaritons in graphene and describe four possible ways of coupling electromagnetic radiation in the terahertz (THz) spectral range to this type of surface waves: (i) the attenuated total reflection (ATR) method us- ing a prism in the Otto configuration, (ii) graphene micro-ribbon arrays or monolayers with modulated conductivity, (iii) a metal stripe on top of the gr...
Instabilities, solitons and rogue waves in PT-coupled nonlinear waveguides
Bludov, Yuliy V.; Driben, R.; Konotop, Vladimir V.; Malomed, B. A.We considered the modulational instability of continuous-wave backgrounds, and the related generation and evolution of deterministic rogue waves in the recently introduced parity–time (PT )-symmetric system of linearly coupled nonlinear Schr¨ odinger equations, which describes a Kerr-nonlinear optical coupler with mutually balanced gain and loss in its cores. Besides the linear coupling, the overlapping cores a...
Superfluidity breakdown of periodic matter waves in quasi one-dimensional annul...
Yulin, Alex V.; Bludov, Yuliy V.; Konotop, Vladimir V.; Kuzmiak, Vladimir; Salerno, MarioWe investigate, both analytically and numerically, the quasisuperfluidity properties of periodic Bose-Einstein condensates (BECs) in a quasi-one-dimensional (1D) ring with optical lattices (OL) of different kinds (linear and nonlinear) and with a moving defect of an infinite mass inside. To study the dynamics of the condensate we used a mean-field approximation describing the condensate by use of the Gross-Pita...
Unusual reflection of electromagnetic radiation from a stack of graphene layers...
Bludov, Yuliy V.; Peres, N. M. R.; Vasilevskiy, MikhailWe 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 a minimum (maximum) for the p (s)-polarizatio...
Exact solution for square-wave grating covered with graphene : surface plasmons...
Peres, N. M. R.; Bludov, Yuliy V.; Ferreira, Aires; Vasilevskiy, MikhailWe provide an analytical solution to the problem of scattering of electromagnetic radiation by a square-wave grating with a flat graphene sheet on top.We show that for deep groves there is a strong plasmonic response, with light absorption in the graphene sheet reaching more than 45% due to the excitation of surface plasmon-polaritons. The case of a grating with a graphene sheet presenting an induced periodic m...
Resonant excitation of confined excitons in nanocrystal quantum dots using surf...
Bludov, Yuliy V.; Vasilevskiy, MikhailSurface plasmon-polaritons (SPPs) in a multilayer structure consisting of a metallic film and one or more layers of nanocrystal (NC) quantum dots (QDs) are studied theoretically. It is shown that there is a resonance coupling between the plasmonpolaritons propagating along the metal/NC-layer interface and excitons confined in the dots, which produces a considerable effect on the optical properties of the struct...
Graphene-based polaritonic crystal
Bludov, Yuliy V.; Peres, N. M. R.; Vasilevskiy, MikhailIt is shown that monolayer graphene deposited on a spatially periodic gate behaves as a polaritonic crystal. Its band structure depending on the applied gate voltage is studied. The scattering of electromagnetic radiation from such a crystal is presented calculated and its spectral dependence is analyzed in terms of Fano-type resonances between the reflected continuum and plasmon-polariton modes forming narrow ...
Tunable graphene-based polarizer
Bludov, Yuliy V.; Vasilevskiy, Mikhail; Peres, N. M. R.It is shown that an attenuated total reflection structure containing a graphene layer can operate as a tunable polarizer of the electromagnetic radiation. The polarization of the reflected electromagnetic wave is controlled by adjusting the voltage applied to graphene via external gate, as demonstrated for the cases of linearly and circularly polarized incident radiation. The mechanism is based on the resonant ...
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