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Supervisor: Dr., leading scientist Nickolay Sergeevich Shevyakhov |
Scientific
workersSupervisor: Shevyakhov Nickolay Sergeevich
Research
activitiesThe staff of the second thematic group performs an investigations of wave processes in active crystals (piezoelectrics, ferroelectrics, ferrites) to reveal a new methods of information transforming and to develop methods of acoustical spectroscopy of nonhomogeneous condensed mediums. The result of performed investigations is the prediction of possibility of negative longitudinal shift of confined beams formed by flexural waves, by Langmuir waves in isotropic collisionless plasma, by electromagnetic waves, acustic waves.
In last years the researches were performed of the propagation effects of magnetoelastic and electric-acoustic surface waves in the systems of moving domain walls (section "interaction between acoustic bulk or surface waves and moving domain walls in ferroelectric and ferrite crystals" of the theme "Parametric effects of the interaction of waves with moving interphase boundaries in active crystals", which have as a goal the revealing and analysis of additional possibilities of signal processing of information with electric-acoustic and magnetoelastic surface (boundary) shear waves by controlling motion of 180-degree domain wall that keep that waves.)
The basic result was the prediction of new sub-class of surface waves called non-collinear because of inherent non-colliniarity of wave vector caused by the motion of holding them boundary. The practical meaning consists in the proving of the possibility of translational transfer of waves by boundary, what is possible to use, for example, for scanning of crystall by surface non-collinear wave in zigzag trajectory.
The group under the supervision of Dr. Konstantin V. Krutitsky performs investigations of quantum processes of interaction of optical range photons with solids and with systems of ultracold Bose and Fermi gases. The rigorous microscopic quantum theory of the interaction of ultracold Bose and Fermi gases with the electromagnetic field of vacuum and laser photons is developed. Starting from the first principles of QED we have derived the general system of Maxwell-Bloch equations for atomic creation and annihilation operators and the propagation equation for the laser field which can be used for the self-consistent analysis of various linear and nonlinear phenomena in atom optics at high densities of the atomic system. All known equations which are used for the description of the behaviour of an ultracold atomic ensemble in a radiation field can be obtained from our general system of equations in a low-density limit.
Part of the work is carried out in the frames of international scientific collaboration with the group of Professor Jurgen Audretsch at Konstanz University (Germany) and at Texas A&M University (USA). The project under the general title "Microscopic approach to the problem of quantization of electromagnetic field in ultracold gases" is supported by Deutsche Forschungsgemeinschaft and Alexander-von-Humboldt Foundation.
The group under supervision of Dr. Konstantin Krutitsky performs investigations of surface optical phenomena in solids.
The influence of discrete structure of dielectric medium on the distrubution of electromagnetic field near the surface is regarded for the needs of near-field optical microscopy of superfine resolution. Distorting influence of small probe on the distribution of detecting field is estimated. It is shown that discrete structure of the medium affects the behaviour of electromagnetic field mostly at two lattice constants far from surface. It make it possible to perform numerical estimations for the dimentions of the region of reflected and transmitted waves formation.
The microscopic theory of transition layer on the ideal surface of absorbing or non-absorbing dielectrics is developed. The consideration is carried out in the frames of concept about discrete-continuous dielectric. In this concept the fields are taken into account of discretely distributed atoms (molecules) inside Lorentz sphere surrounding the observation point. The discrete structure of medium is shown to lead to the anomalous behaviour of the field near the surface. The thickness of transition layer may be found from the experimental values of the amplutude of reflected wave. The formula for this amplitude is obtained in view of nonhomogeneous transition layer.
The boundary-value problem of quantum optics for the spontaneous emission of atom in a one-dimentional chain of discrete dipoles is solved. It is shown that taking into account of discrete stucture of medium leads to near-field effect.
An estimations of near-field effect magnitude in mediums with different types of spatial distribution of atoms are obtained.
The group is closely collaborates with Ulyanovsk State University.
Thematically
close webpagesThe huge list of books, special issues and joural articles (~500) on photonic crystals.
Research groups:
Ulyanovsk, 432011, Goncharov Str., 48
Ulyanovsk Branch of the Institute of
Radio Engineering and Electronics of RAS
E-mail: ufire@mv.ru
UB IRE RAS | Research activities
