A5034378601- Gyrotron and Vacuum Electronics Research
- Particle Accelerators and Free-Electron Lasers
- Carbon Nanotubes in Composites
- Graphene research and applications
- Electromagnetic wave absorption materials
- Crystallography and Radiation Phenomena
- Photonic and Optical Devices
- Advanced Antenna and Metasurface Technologies
- Terahertz technology and applications
- Laser Design and Applications
- Particle accelerators and beam dynamics
- Advanced X-ray Imaging Techniques
- Mechanical and Optical Resonators
- Metamaterials and Metasurfaces Applications
- Photonic Crystals and Applications
- Nanotechnology research and applications
- Topological Materials and Phenomena
- Quantum Chromodynamics and Particle Interactions
- Advanced Electron Microscopy Techniques and Applications
- Laser-Plasma Interactions and Diagnostics
- Plasmonic and Surface Plasmon Research
- Semiconductor materials and interfaces
- Advanced NMR Techniques and Applications
- Photocathodes and Microchannel Plates
- Electromagnetic Compatibility and Noise Suppression
Belarusian State University
2012-2021
National Research Tomsk State University
2016-2021
Institute of Mechanics
2016
Bulgarian Academy of Sciences
2016
HUN-REN Centre for Energy Research
2016
Thanks to its high electrical conductivity, a graphene plane presents good shielding efficiency against GHz electromagnetic radiations. Several planes separated by thin polymer spacers add their conductivities arithmetically, because each of them conserves the intrinsic properties isolated graphene. Maximum absorption radiations for frequency around 30 is achieved with six planes, which optimum number. This remarkable result demonstrated experimentally from measurements performed in Ka band...
Fresnel equations predict that an ultrathin free standing conductive film, thousands times thinner than skin depth, is capable to absorb up 50% of incident electromagnetic radiations. In the microwave range, same holds true for a graphene sheet. We demonstrate theoretically and prove experimentally absorptance can be enhanced considerably by depositing on dielectric substrate. On experimental side, we obtain 80% 65% at 30 GHz 1 THz, respectively. Theory predicts higher achieved with suitable...
The ability of thin conductive films, including graphene, pyrolytic carbon (PyC), graphitic PyC (GrPyC), graphene with islands (GrI), glassy (GC), and sandwich structures made all these materials separated by polymer slabs to absorb electromagnetic radiation in microwave-THz frequency range, is discussed. main physical principles making a basis for high absorption heterostructures are explained both the language theory using representation equivalent electrical circuits. idea carbonaceous...
A new type of light-weight material produced by 3D printing consisting nano-carbon doped polymer layer followed a dielectric is proposed. We performed temperature dependent characterization and measured the electromagnetic (EM) response samples in GHz THz range. The structural characteristics, crystallization, melting were observed to be strongly affected presence number layers sandwich structure. measurements show great potential such periodic for compatibility applications microwave...
We investigated several proposals utilizing the unique electronic properties of carbon nanotubes (CNTs) for a broad range applications to THz optoelectronics, including generation by Cerenkov-type emitters based on and hot electrons in quasimetallic nanotubes, frequency multiplication chiral-nanotube-based superlattices controlled transverse electric field, radiation detection emission armchair strong magnetic field. Dispersion equations electron beam instability threshold conditions...
The microscopic theory of bilayer graphene nonlinear interaction with coherent electromagnetic radiation is developed. Liouville--von Neumann equation for a single-particle density matrix in the multiphoton resonant approximation solved. We consider low-energy excitations Fermi-Dirac sea THz pump radiation. obtained solutions disclose Rabi oscillations and graphene. On basis numerical simulations we examine rates high-harmonic at particle-hole annihilation field strong wave. show that domain...
A mechanism of stimulated emission electromagnetic radiation by an electron beam in carbon nanotubes is theoretically considered. Three basic properties nanotubes: a strong slowing down surface waves, ballisticity the motion over typical nanotube length, and extremely high current density reachable nanotubes, allow proposition them as candidates for development nanoscale Cherenkov-type emitters, analogous to traveling-wave tube free laser. Dispersion equations electron-beam instability...
Electromagnetic properties of pyrolytic carbon (PyC) films with thickness from 5 to 241 nm are studied experimentally and numerically at 28 GHz. We observe that PyC capable absorb up 50% microwave power in the Ka-band. By using boundary conditions rectangular waveguide, we demonstrate theoretically can be absorbed a conductive film much smaller than skin depth. The results modelling for on silica substrate excellent coincidence experimental data.
Band gap control by an external field is useful in various optical, infrared and THz applications. However, widely tunable band gaps are still not practical due to variety of reasons. Using the orthogonal tight-binding method for $\pi$-electrons, we have investigated effect electric on a subclass monolayer chevron-type graphene nanoribbons that can be referred as jagged nanoribbons. A classification such ribbons was proposed applied fields up SiO$_2$ breakdown strength ($1$ V/nm) were...
Ultrafast quantum dynamics of interband transitions in monolayer graphene initiated by strong laser radiation is investigated. A microscopic theory describing nonlinear interaction beyond the Dirac cone approximation and applicable to full Brillouin zone hexagonal nanostructure with tight-binding electronic states developed. Coherent effects toward control macroscopic are considered. In particular, we consider Rabi oscillations, rapid adiabatic passage for population transfer, multiphoton...
By exploring the Salisbury screen approach, we propose and demonstrate a thin film absorber of terahertz (THz) radiation. The is comprised less than 100 nm thick layer pyrolytic carbon deposited on stretchable polydimethylsiloxane (PDMS) followed by metal film. We that being overall 200 microns thick, such sandwich structure absorbs resonantly up to 99.9%of incident THz radiation, absorption resonance determined polymer thickness, which can be adjusted stretching.
Surface plasmon-polariton waves with low-phase speed in carbon nanostructures can be utilized for the generation of coherent terahertz radiation through Čerenkov mechanism, effect being especially pronounced bilayer and multilayer graphene. Using many-body formalism tight-binding approach, we derived dispersion equations surface In single-layer graphene, phase is about three to five times smaller than light a vacuum. inter-layer electron tunneling suppresses reduction speed. Reduction by as...
The free electron laser on the basis of parametric (quasi-Cerenkov) instability is considered. Threshold conditions for this process are obtained. It shown that rather rigid requirements particle beam needed in X-ray region.
The propagation of an electron beam over a graphene/dielectric sandwich structure is considered assuming the distance between graphene layers in large enough to prevent interlayer tunneling. A dispersion equation for surface electromagnetic modes propagating along sheets derived and \ifmmode \check{C}\else \v{C}\fi{}erenkov synchronism wave nonrelativistic predicted at achievable parameters system. Generation frequency tuning proposed by varying doping, number sheets, etc.
Microwave absorption properties of onion-like carbons (OLC) have been studied in microwave frequency range. A consistent analysis the electromagnetic (EM) attenuation provided by OLC-based suspensions with variable concentration OLC has carried out Ka-band (26-37 GHz). The first study spectral features given (7.2-28.6 volume percents stuff vaseline) demonstrates that percolation threshold is strongly dependent on average nanocarbon cluster size. It found also raising annealing temperature a...
We studied electromagnetic properties of pyrolytic carbon (PyC) films with thicknesses from 9 nm to 110 nm. The PyC consisted randomly oriented and intertwined graphene flakes a typical size few nanometers were synthesized by chemical vapor deposition (CVD) at 1100 °C on quartz substrate. reflectance transmittance these in Ka-band, 26–37 GHz, both experimentally theoretically. discovered remarkably high absorption loss up 50% incident power, along stability, makes attractive for (EM)...
Basic mechanisms of the interaction electron beam tavelling through a carbon nanotube with electromagnetic wave, resulting in radiative instability and generation stimulated radiation, are considered. The effect surface wave slow-down CNT (c/v > 100) [Slepyan et al., Phys. Rev. B 60, 17136, 1999] is exploited to synchronize thus realize Cherenkov radiation mechanism. Alternative mechanism proposed based on undulator emission arising due interband transitions electrons moving nanotube....