Search academic texts

Information × Registration Number 0225U002242, (0124U000466) , R & D reports Title Electrodynamics of vortex laser beams in the terahertz range popup.stage_title Розробка теоретичних методів дослідження та методів математичного моделювання закономірностей формування вихрових лазерних пучків безперервного випромінювання терагерцового діапазону, особливостей їх поширення та фокусування. Head Dehtiarov Andrii V., Кандидат фізико-математичних наук Registration Date 25-02-2025 Organization V.N. Karazin Kharkiv National University popup.description1 The main goal of the project is to propose new and effective intra-resonator and extra-resonator methods of forming vortex laser beams of continuous radiation in the terahertz range, to establish the physical features of their propagation and focusing. popup.description2  The theory and methods of mathematical modeling have been developed to study the physical regularities of the vortex laser beams formation of continuous radiation in the terahertz range, the features their propagation and focusing. Analytical expressions for non-paraxial mode diffraction of metallic and dielectric waveguide resonators of a terahertz laser have been obtained. The interaction between resonator modes and spiral phase plate was studied taking into account different topological charges (n). In free space, the spiral phase plate for the exciting mode TE11 from the profile with the maximum intensity in the center (n = 0) forms an asymmetric ring with two maxima (n = 1, 2) has been established. For the exciting mode TE01, the initial transverse annular (n = 0) field intensity structure is transformed into a structure with the maximum radiation intensity in the center (n = 1), and then again into an annular one (n = 2). For the linearly polarized EH11 mode, the structure with the maximum intensity in the center (n = 0) forms a ring (n = 1, 2). It is shown that the phase front of the TE11 and EH11 modes changes from spherical to spiral with one axial singularity point, while in the phase profile of the TE01 mode there is a region with two and three off-axis phase singularities. The wave characteristics of vortex laser beams during their sharp focusing are theoretically investigated. It is shown that with a topological charge of the spiral phase plate n = 0, the EH11 mode has a maximum of radiation intensity on the axis. The introduction of a topological charge n leads to the appearance of a minimum of radiation intensity on the axis, as well as to an increase in the size of the focal spot. However, for the TE01 mode, at topological charges n = 0 and n = 2, the intensity distribution retains a ring-shaped shape, and at n = 1 the beam profile becomes Gaussian. The wavefront in the focal region of the lens for the EH11 and TE01 mode components transforms from s Product Description popup.authors Hurin Oleh V. Dziubenko Mykhailo I. Dubinin Mykola M. Maslov Viacheslav O. Riabykh Valerii M. Svystunov Oleh O. Seniuta Vladyslav S. popup.nrat_date 2025-02-25 Close