Izvestiya of Saratov University.
Physics
ISSN 1817-3020 (Print)
ISSN 2542-193X (Online)

графен

Characteristics of induced radiation under the action of short high-frequency pulses on graphene

Background and Objectives: The nonlinear effects of high-harmonic generation in various materials provide new tools for studying ultrafast electron dynamics and open up a possible way to create coherent light sources in currently inaccessible frequency ranges. Graphene is regarded as one of the most promising materials for these purposes.

Correlation relations for graphene and its thermal radiation

Background and Objectives: The thermal radiation of a graphene sheet is considered, as well as the power absorbed by the specified sheet per unit surface in the thermodynamic equilibrium with vacuum radiation. From the comparison of these values, correlation relations are established for fluctuations in the surface current density in graphene and in a 2D conductive sheet similar to it, described by surface conductivity.

Plasmonic Rectification of Terahertz Radiation in a Grating-gated Graphene

The theory of the plasmonic rectification of terahertz radiation in a homogeneous graphene gated by a metal grating with an asymmetric unit cell is developed.

Total Conversion of Terahertz Wave Polarization by Graphene Microribbon Array without Magnetic Field

The polarization conversion of terahertz radiation by the periodic array of graphene microribbons located at the surface of a high-refractiveindex dielectric substrate (prizm) is studied theoretically. Polarization conversion at the plasmon resonance frequencies takes place without applying external DC magnetic field. It is shown that giant (up to total) polarization conversion can be reached at the total internal reflection of THz wave from the periodic array of graphene nanoribbons.

The Graphene Based Terahertz Transistor

Background and Objectives: Due to the lack of a substantial energy gap in graphene nanoribbons there are difficulties to create a fast-switching transistors for digital circuits using them. In a number of recent works, the usage of graphene nanoribbons in tunneling transistors, field effect transistors, transistors with negative resistance and in generators with pumping has been proposed for amplification of analog signals.

Linear Model of Surface Terahertz Plasmons Amplification in Two Parallel Graphene Sheets

Amplification of terahertz plasmons in a pair of parallel active graphene monolayers is studied theoretically. It is shown that the antisymmetric mode increment of plasmons in the two parallel graphene monolayers may be several times greater than that in a single graphene layer due to deceleration of the antisymmetric plasmon mode as compared to the plasmon mode in a single graphene monolayer.

Detection of Terahertz Radiation in Graphene Structure under Conditions of Strong Spatial Inhomogeneity of the Plasmon Electric Field

Background and Objectives: Research of terahertz (THz) wave rectification in graphene shows the increase of the rectified current in p-n graphene structures relatively to graphene having only n- or p-type of conductivity. The p-n junctions in graphene may be created by both a chemical or electrical doping of graphene. There were discussed several physical mechanisms for wave rectification in graphene structures, that are the photothermoelectric effect, Drude heating of carriers by THz radiation and nonlinear plasmonic effects.

Negative Dispersion, Refraction and Backward Polaritons: Impedance Approach

Background and Objectives: The dispersion equations of surface plasmon-polaritons are derived for the general case of layered dissipative structures. The waves are classified as gliding with energy flow into structure from vacuum and leakage ones. The dispersion equations and conditions for the existence of slow and fast gliding and leaky waves, as well as forward and backward waves are considered.