21 research outputs found
ELECTRONICALLY CONTROLLED NONLINEAR DEVICES BASED ON THE GRAPHENE PLASMONICS PLATFORM IN THE FAR AND MID-INFRARED RANGE. REVIEW
No full textBackground. The relevance of the topic is due to the need to master the infrared (IR) range for optical
telecommunication systems, IR spectroscopy and biophotonics applications and is dictated by the needs of nonlinear
IR optics for the implementation of active optical functions based on graphene, such as generation of IR radiation,
frequency conversion for applications in optical communications, materials processing, precision measurements, spectroscopic
sensing and biological sensors. The purpose of this work is to present the principles of construction and operation
of electrically tunable nonlinear devices in the far and mid-IR range: harmonic generators and multipliers, frequency
converters and mixers based on graphene metasurfaces using the latest achievements of graphene plasmonics.
Materials and methods. Graphene plasmonics. Results and conclusions. The unique properties make electronically
controlled nonlinear devices in the far and medium IR range a promising choice for the future nonlinear frequency
converter, optical control and information processing on a graphene plasmonics board
MODELING THE CONTROLLABILITY OF CHARACTERISTICS OF PLASMON GRAPHENE NANOANTENNA GRATINGS IN THE MID-IR RANGE
No full textBackground. The introduction of nanoantennas for optical wireless communications in the infrared
(IR) and visible bands enables higher data rates while reducing antenna size. The ability to tune the characteristics of
graphene by chemical doping or bias voltage is relevant in the development of reconfigurable nanoantennas. The goal
of the work is to study the characteristics (S-parameters, radiation patterns (RP)) of plasmonic graphene nanoantenna
(PGNA) arrays, their controllability and the possibility of frequency scanning when changing the chemical potential of
graphene (by applying an external electric field) in the mid-IR range. Matherials and methods. The use of graphene,
which has good electrical conductivity, controlled conductivity and plasmonic properties in the terahertz (THz), far-IR
and mid-IR ranges, is one of the most promising alternatives to noble metals (Au and Ag) as plasmonic materials at
optical frequencies only. Modeling of the characteristics of PGNA arrays was carried out using the electrodynamic
modeling program CST Microwave Studio 2019, which makes it possible to solve scientific problems associated with the design of graphene antennas in the IR wavelength range. Results. The results of modeling the controllability of the
characteristics (S-parameters, DP) of a element of the antenna array (PGNA of rectangular geometry) and PGNA arrays
at the resonant frequencies of the fundamental mode of surface plasmon polaritons (SPP) are obtained and the
possibility of scanning in frequency when changing the chemical potential of graphene (by applying an external electric
fields) in the mid-IR range. Conclusions. From the results of modeling the characteristics of PGNA arrays, it follows
that with an increase in the chemical potential of graphene (in the range of values 0,3–1 eV), the operating frequencies
are adjusted (frequency scanning) in the mid-IR range, the gain of the PGNA array increases, the RP main
lobe narrows, and the RP side lobe level decrease; with an increase in the number of single elements (N = 256), the
levels of the RP side lobes decrease and better controllability of the RP main lobe is observed
Mathematical Modeling of Tunable Graphene-based Carbon Nanotube-Waveguiding Structures and Devices in the THz and Near-IR Frequency Ranges
No full text
Magnetoplasmonic effects at the diffraction of terahertz waves on magnetically biased graphene metasurfaces
No full textBackground. The purpose of this work is a numerical study of the features of magnetoplasmonic effects arising from the diffraction of THz waves on graphene metasurfaces in external magnetic fields. Materials and methods. The advantage of graphene over conventional plasmonic materials for use in plasmonic and magneto-optical devices is the high sensitivity of surface magnetoplasmon-polaritons to external magnetic fields, since the cyclotron frequency is comparable to the plasmonic frequency in the THz and far IR ranges. A numerical study of magnetoplasmonic resonances of graphene metasurfaces depending on the induction of an external magnetic field and modeling of 3D e-Field scattering patterns on an element of a graphene metasurface (rectangular graphene nanoribbon) was carried out using the CST Microwave Studio program. To solve the electrodynamic diffraction problem using MWS CST, a method was chosen to analyze a graphene metasurface (an infinite periodic 2D structure) by applying periodicity conditions that reduce the problem for an infinite structure to the analysis of one period. Results. The results of modeling the 3D e-Field scattering diagram on an element of a magnetically biased graphene metasurface (a rectangular graphene nanoribbon) of an incident TEM-wave of p- and s-polarization for the vertical and horizontal components of the diffracted field at magnetoplasmon resonance frequencies in the THz range. An analysis of magnetoplasmonic effects was performed based on the calculation of the ratio of components of the diffracted field and the axial ratio at the points of cross-section (φ=0˚) of the main lobe of the 3D e-Field scattering diagrams at normal incidence of a TEM-wave of p- and s-polarization. Conclusions. From the results of the numerical study of the characteristics of the magnetically biased graphene metasurfaces it follows that magnetoplasmonic effects are observed at resonant frequencies, i.e. the appearance of another component of the diffracted field, orthogonal to the exciting one, as well as the magneto-optical effects of rotation of the plane of polarization of the transmitted wave (Faraday effect), rotation of the plane of polarization and the appearance of ellipticity of a linearly polarized wave during reflection of a linearly polarized wave from the graphene surface (magneto-optical Kerr effect), depending on the magnitude of the external magnetic field
Electronically Tunable Broadband THz Frequency Multipliers Based on Multilayer Nonlinear Graphene Metasurfaces
No full textAn efficient nonlinear frequency multiplication mechanism in ferrite loaded waveguide structures
No full textElectrodynamic and Probabilistic Calculation of Performances of THz devices Based on Periodic Mtilayer Graphene-Dielectric Structures
No full text"Лахунский ветеринарный папирус": перевод, историко-филологический комментарий
No full textВ работе исследовался Лахунский ветеринарный папирус. Была сделана иероглифическая транскрипция, транслитерация и перевод, сопоставлены различные трактовки текста, в том числе с точки зрения медицины. Весьма примечательным кажется то, что текст записан линейной иероглификой. Было предложено два возможных объяснения этой проблемы: 1) линейная иероглифика используется как средство борьбы со смертью; 2) Линейная иероглифика используется ввиду тесной связи текста с жертвенными ритуалами и сакральной сферой.The subject of the paper is the Lahun Veterinary papyrus. There was accomplished hieroglyphic transcription, transliteration and translation of the text. The most prominent feature of the text is that it was written in linear hieroglyphics. The author supposes two possible explanations of this issue: linear hieroglyphics was considered to be an effective cure for death; the papyrus was closely related to sacrifices, so linear hieroglyphics was used
On the issue of reasons for instituting criminal proceedings (The aspects of the new Criminal Procedure Code edition)
No full textThe article’s issue is analyzes of reasons for instituting of criminal proceedings in the sphere of the latest Criminal Procedure Code edition. The interrelation of definitions «the applicant’s safety» and «the applicant’s anonymity» in the article is described. The author gives the legal assessment of investigators’ action while checking case papers derived from a prosecutor
