Yuliy V. Bludov

A primer on surface plasmon-polaritons in graphene

We 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 using a prism in the Otto configuration, (ii) graphene micro-ribbon arrays or monolayers with modulated conductivity, (iii) a metal stripe on top of the graphene layer, and (iv) graphene-based gratings. The text provides a number of original results along with their detailed derivation and discussion.

Optical bistability of graphene in the terahertz range

We are grateful to D. K. Ferry and A. A. Ignatov for sharing their insights on the early developments of Boltzmann transport theory for semiconductors, and we thank N. A. Mortensen for useful remarks. This work was partially supported by the FEDER COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) through Grant No. PEst-C/FIS/UI0607/2013. We acknowledge support from the EC under Graphene Flagship (Contract No. CNECT-ICT-604391). The Center for Nanostructured Graphene (CNG) is sponsored by the Danish National Research Foundation, Project No. DNRF58. The work contract of J.E.S. is financed within the framework of the Program of Recruitment of Post Doctoral Researchers for the Portuguese Scientific and Technological System, with the Operational Program Human Potential (POPH) of the QREN, participated in by the European Social Fund (ESF) and national funds of the Portuguese Ministry of Education and Science (MEC).

Stable dark solitons in PT -symmetric dual-core waveguides

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 stability is investigated in a numerical form via computation of eigenvalues for modes of small perturbations. Stability regions are thus identified in the parameter space of the system and verified in direct simulations. Collisions between stable dark solitons are briefly considered too.

Tunable graphene-based polarizer

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 angle is controlled by adjusting the voltage applied to graphene via external gate. The mechanism is based on the resonant coupling of

Rogue waves as spatial energy concentrators in arrays of nonlinear waveguides.

p-

Instabilities, solitons and rogue waves in -coupled nonlinear waveguides

polarized electromagnetic waves to the surface plasmon-polaritons in graphene. The presented calculations show that, at resonance, the reflected wave is almost 100%

Graphene-based polaritonic crystal

s-

Unusual reflection of electromagnetic radiation from a stack of graphene layers at oblique incidence

polarized.

Enhancing the absorption of graphene in the terahertz range

In an array of nonlinear waveguides, a giant compression of the input beam can be achieved by exciting a rogue wave. Input field almost homogeneously distributed over hundreds of waveguides concentrates practically all the energy into a single waveguide at the output plane of the structure. We determine the required input profile of the electric field to achieve this. We illustrate the phenomenon by modeling the array by direct numerical simulations of the discrete nonlinear Schrödinger equation.

Exact solution for square-wave grating covered with graphene: surface plasmon-polaritons in the terahertz range

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?dinger equations, which describes a Kerr-nonlinear optical coupler with mutually balanced gain and loss in its cores. Besides the linear coupling, the overlapping cores are coupled through the cross-phase-modulation term too. While the rogue waves, built according to the pattern of the Peregrine soliton, are (quite naturally) unstable, we demonstrate that the focusing cross-phase-modulation interaction results in their partial stabilization. For 𝒫𝒯-symmetric and antisymmetric bright solitons, the stability region is found too, in an exact analytical form, and verified by means of direct simulations.