name: Конфигурирование индикатрисы рассеяния наноструктур, поддерживающих возбуждение мультипольных моментов высоких порядков
keyword_list: Scattering, Mie theory, Multipole expansion, Quasi normal modes
abstract: The co-existence and interplay of electric and magnetic modes make it possible to realize constructive or destructive interference leading to extraordinary scattering signatures . Among them, dielectric nanoparticles were shown to support the nonradiating states known as anapoles,  destructive interferences of the elementary electric dipole with the toroidal dipole moment, leading to a reduction of the overall far-field scattering and confined near fields, a substantial increase of the total scattering cross-section aka superscattering , the formation of the quasi bound state in the continuum qBICs via power transfer to higher quality factor multipolar resonance, and strong asymmetric scattering that is usually associated with the Kerker effect. The extending of these optical phenomena to metasurfaces structurers and at the same time benefiting from the additional lattice resonances has widened the applications areas to flat optics. For instance, the maximally chiral metasurface mediated by the qBICs, the near-field directionality of Huygens’ dipoles, that enables the physics of highly efficient Mie-resonant passive and active dielectric metadevices. The recent advancements of non-conservative physics have taken advantage of the PT-symmetries studies of various non-Hermitian systems to reveal new perspectives of the scattering problem. Assisted by a sweeping landscape of eigenfrequencies, such advances uncovered various optical effects. Complex-domain studies implement physical quantities such as the eigenstates’ trajectories in a parametric figure and reduce the complexity of the problem by limiting the analysis of the optical response to usually few dominant modes. Moreover, recent works have implemented robust techniques to solve the eigenproblem of Maxwell’s equations in dispersive and complex structures. Consequently, they have advanced the concept of the intrinsic multipoles, i.e. decomposition of the eigenfields resulting in excitation independent multipoles that are fundamentally connected to the structure symmetry. 
  This work investigates scattering manipulation by high index dielectric structures through utilizing multipolar expansion methods and symmetry characteristics of Non-Hermitian systems; exploring approaches utilizing the electromagnetic multipoles expansion method to control scattering at will;  design efficient energy mapping nanodevices that reshape light emitted by broadband sources; exploring extreme light scattering phenomena, developing comprehensive analytical models through electromagnetic multipoles expansion to describe them and laying out a design strategy; and describe and manipulate interacting fields of metasurfaces and finite subwavelength arrays.
  The thesis research covers the transverse Kerker effect by high-index subwavelength particles with the simultaneous near-suppression of both forward and backward scattered power. This novel effect in an opposite scenario to the generalized Kerker effect occurs when in-phase electric and magnetic dipoles are acquired antiphase relation with the corresponding quadrupoles. It was shown that the electric dipole Fano resonance with off-resonance quadrupoles play an essential role to achieve the transversal scattering requirements. The presented effect can be utilized for efficient beam control, strong field enhancement required for nonlinear interaction, and highly efficient sensing. In chapter 2, the author has shown with an experimental demonstration that metasurfaces assembled from transverse scatterers enable complete transparency. In contrast to the Huygens metasurfaces, both amplitude and phase of an incident wave are unaffected. It was shown the almost non-scattering regime mediates an enhanced near field, which could pave the way for several optical effects, such as nonlinear interactions, lasing, Raman scattering, and sensing. In chapter 3, it was shown that reducing index contrast on the outer walls of a resonator-surrounding medium system leads to broadband generalized Kerker effect. Consequently, high order multipolar resonances broaden and overlap at the short wavelength region resulting in an enhanced total scattering. The highly directive scattering was explained via Cartesian multipole expansion of the asymmetry parameter. Outcomes of this research are essential for tuning the scattering direction by changing the medium in which a nanoantenna is embedded. The research work that forms the basis of this dissertation has the following contributions: predicting the novel Transverse Kerker effect in high-index dielectric particles by employing the electromagnetic multipole expansion method, realising the fully transparent metasurface at the spectrum points of the transverse Kerker effect, uncovering the dependencies of the scattering strength and scattering directivity on the index contrast in a scatterer surrounded by nonabsorptive mediums and also revealing mechanisms via modes interference to obtain multi-frequency superscattering points in particles that lack spherical symmetry.
chairman_dissertation_council.name: Николай
chairman_dissertation_council.surname: Никоноров
chairman_dissertation_council.patronymic: Валентинович
chairman_dissertation_council.position: профессор (квалификационная категория "ведущий профессор"), факультет фотоники
chairman_dissertation_council.degree: Доктор физико-математических наук
chairman_dissertation_council.rank: Профессор
chairman_dissertation_council.wos_research_id: 7003772604
chairman_dissertation_council.scopus_author_id: 7003772604
chairman_dissertation_council.territory: РОССИЯ
organization_supervisor.name: Владимир
organization_supervisor.surname: Васильев
organization_supervisor.patronymic: Николаевич
organization_supervisor.position: ректор
organization_supervisor.territory: РОССИЯ
rubrics.code: 29.31.01
rubrics.name: Общие вопросы
rubrics.code: 29.19.22
rubrics.name: Физика наноструктур. Низкоразмерные структуры. Мезоскопические структуры
oecds.code: 02.10.NS
oecds.name: NANOSCIENCE & NANOTECHNOLOGY
oecds.code: 01.03.SY
oecds.name: OPTICS
oecds.code: 01.01.UR
oecds.name: PHYSICS, MATHEMATICAL
speciality_codes.name: Оптика
speciality_codes.code: 01.04.05
supervisors.fio: Шалин А. С.
supervisors.scientific_degree: Доктор физико-математических наук
supervisors.speciality_code: Оптика
supervisors.responsible_type: Научный руководитель
opponents.fio: Иванов О. В.
opponents.scientific_degree: Доктор физико-математических наук
opponents.speciality_code: Оптика
opponents.responsible_type: Оппонент
opponents.fio: Лавриненко А. В.
opponents.scientific_degree: Доктор физико-математических наук
opponents.speciality_code: Оптика
opponents.responsible_type: Оппонент
protection_organization.short_name: УНИВЕРСИТЕТ ИТМО; НИУ ИТМО; ИТМО
protection_organization.name: ФЕДЕРАЛЬНОЕ ГОСУДАРСТВЕННОЕ АВТОНОМНОЕ ОБРАЗОВАТЕЛЬНОЕ УЧРЕЖДЕНИЕ ВЫСШЕГО ОБРАЗОВАНИЯ "НАЦИОНАЛЬНЫЙ ИССЛЕДОВАТЕЛЬСКИЙ УНИВЕРСИТЕТ ИТМО"
protection_organization.ogrn: 1027806868154
protection_organization.supervisor_name: ВЛАДИМИР
protection_organization.supervisor_surname: ВАСИЛЬЕВ
protection_organization.supervisor_patronymic: НИКОЛАЕВИЧ
protection_organization.organization_type: Организация
protection_organization.okogu: Министерство науки и высшего образования Российской Федерации
protection_organization.okopf: Федеральные государственные автономные учреждения
author_organization.short_name: УНИВЕРСИТЕТ ИТМО; НИУ ИТМО; ИТМО
author_organization.name: ФЕДЕРАЛЬНОЕ ГОСУДАРСТВЕННОЕ АВТОНОМНОЕ ОБРАЗОВАТЕЛЬНОЕ УЧРЕЖДЕНИЕ ВЫСШЕГО ОБРАЗОВАНИЯ "НАЦИОНАЛЬНЫЙ ИССЛЕДОВАТЕЛЬСКИЙ УНИВЕРСИТЕТ ИТМО"
author_organization.ogrn: 1027806868154
author_organization.supervisor_name: ВЛАДИМИР
author_organization.supervisor_surname: ВАСИЛЬЕВ
author_organization.supervisor_patronymic: НИКОЛАЕВИЧ
author_organization.organization_type: Организация
author_organization.okogu: Министерство науки и высшего образования Российской Федерации
author_organization.okopf: Федеральные государственные автономные учреждения