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Discovery and studies of phenomena for the light beams with singularities of wavefront


Work number - P 4 ALLOWED TO PARTICIPATE

Presented Institute of Physics of the National Academy of Sciences of Ukraine

Authors:
1. ANGELSKY Oleh Vyacheslavovych - professor, doctor of physics and mathematics, director of the Institute of physical, technical and computer sciences of Yuriy Fedkovych Chernivtsi National University.
2. BAZHENOV Volodymyr Yuriyovych – Senior researcher, candidate of physics and mathematics, Senior researcher of the department of gas electronics of the Institute of Physics of NAS of Ukraine.
3. BEKSHAEV Oleksandr Yanovych – Senior researcher, doctor of physics and mathematics, Head of the laboratory of optics and laser physics of the Scientific and Research Institute of Physics of Odessa I.I.Mechnikov National University.
4. BLIOKH Kostyantyn Yuriyovych – Senior researcher, candidate of physics and mathematics, Senior research scientist, Theoretical quantum physics laboratory, RIKEN Claster for Pioneering Research, Wako-shi, Saitama, 351-0198, Japan.
5. VASNETSOV Mikhaylo Viktorovych - professor, doctor of physics and mathematics, Leading researcher of the department of optical quantum electronics of the Institute of Physics of NAS of Ukraine.
6. Vlokh Rostyslav Orestovych – professor, doctor of physics and mathematics, director of the O.G.Vlokh Institute of Physical Optics of the Ministry of Education and Science of Ukraine.
7. MOKHUN Ihor Ivanovych - professor, doctor of physics and mathematics, professor of correlation optics department of Yuriy Fedkovych Chernivtsi National University.
8. SKAB Ihor Petrovych - Senior researcher, doctor of physics and mathematics, vice-director of the O.G.Vlokh Institute of Physical Optics of the Ministry of Education and Science of Ukraine.

The studies that was started in 1989 and actively developed under the leadership of Professor, Corresponding Member of the NAS of Ukraine M.S. Soskin, have included a first laboratory detection of optical vortices and a development of methods for fabricating synthesized-grating holograms. This has been aimed at formation of beams bearing optical vortices, as well as detailed studies of the properties of these vortices, phase structure of their wave fronts, and regularities of their interference. The stability against perturbation properties have been analyzed for the optical vortices with the topological charges higher than unity. The rotation of non-axial optical vortices around the beam axis during phase change of their components has been revealed. The role of Gouy phase in the spatial transformation of the combined beam has been investigated for the first time. In case of the combined beams and in the course of birth and annihilation of optical vortices, violation of the conservation law for the topological charge has been detected. An interference ratio for the orbital angular momentum of the beam components has been obtained. The synthesized optical vortices with non-integer topological charges have been investigated both experimentally and theoretically. A method for generating beams with non-integer topological charges has been suggested. A dynamic process of formation and annihilation of optical vortices has been revealed in active media. These and the other experiments (e.g., generation of second-optical harmonics of the beam with optical vortex and rotation of the wavefront of the optical vortex at four-wave mixing) have given rise to the branch of nonlinear singular optics. It has been revealed that, in ‘per photon’ terms, the orbital angular momentum represents an integer of the units of Planck’s constant. The existence of Doppler rotational effect for the optical-vortex mode has been demonstrated. The first experiments have been carried out in order to transmit a signal using the principle of information encoding by the method of orbital angular momentum. It has been established that a presence of optical vortex in one of the components leads to a so-called C-point of circular polarization in the field with elliptical polarization around it. Thus, the topological transformations of singular structures in randomly polarized fields have become completely understood.

The basic laws have been revealed that govern the appearance and interactions of topological defects of different optical characteristics in inhomogeneously perturbed media. The possibilities for appearance of optical vortices with the aid of parametric crystal optical effects under the influence of inhomogeneous fields and in the presence of acousto-optic interactions have been demonstrated. This enables possibilities for controlling the efficiency of spin-to-orbital conversion by external fields and performing spatial control of the position of the vortex beam in case of acousto-optic interactions.

Fundamental concepts are developed concerning relations between the internal structure of wave fields and their global evolution. Physical principles and mechanisms are revealed responsible for interactions between the intrinsic (polarization) and extrinsic degrees of freedom of light. Based on the unified concept, the influence of the intrinsic singular structure of a light beam on its propagation, refraction, focusing, diffraction, is meaningfully described. A self-consistent system of dynamical characteristics of light is developed, which reveals the fundamental and applied aspects of the topological nature and singularities of structured light fields.

The problems of generation of optical singularities of different types have been considered, including the case of singularities appearing in polychromatic fields. The mechanisms for optical-singularity networks have been established. The links (or primary correlations) between the systems of singularities of different types have been found. The effect of singular-field structures on the other physical systems has been analyzed.

All these results have been obtained for the first time and they have received the approval of world scientific community. They form a holistic concept that reveals the physical and applied aspects of the topological properties and the singularities of light fields. Within some 30 years of extensive work, a new independent branch of modern physical optics has been created. As a consequence, the term ‘singular optics’ suggested by us is now included in the base of keywords and the rubrics of scientific publications.

Number of publications: 275, incl. 4 monographs (2 - published abroad), 11 chapters of monographs (11 - published abroad), 259 articles (239 - in English-language journal with impact-factor). The total number of citations to author publications/h-index of work, according to the databases is respectively: Web of Science - 10063/51, Scopus - 10699/53, Google Shcolar - 14332/57. 1 patent of Ukraine for invention has been received. 5 doctor and 24 candidate dissertations are defended on this subject.

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