Kravchuk P. Photochemical destruction of nano-inhomogeneities of the surface of optical parts by near-field fiber probes

Українська версія

Thesis for the degree of Doctor of Philosophy (PhD)

State registration number

0822U100096

Applicant for

Specialization

  • 105 - Прикладна фізика та наноматеріали

21-12-2021

Specialized Academic Board

ДФ 26.001.240

Taras Shevchenko National University of Kyiv

Essay

It becomes clear that the key concept in analyzing this problem is the dipole and its radiation, in particular in the near-zone. Therefore, an atomic model of an electric dipole was proposed that is closer to reality than the model of the Hertzian dipole or a standard model of dipole with spaced point charges. It is shown that an attempt to apply the Coulomb's law to the atomic dipole should lead to a singularity at a zero point, where the positive charge +q of the atomic nucleus and the equivalent negative charge -q of electron cloud are overlapped and the dipole collapses, and the impossibility of polarization of the atom in the future. It was found that oscillation of an electronic cloud under the action of an alternating external field leads to a partial decompensation of charge fields, which depends on the dipole's shoulder and determines the force of attraction of unlike charges. The use in the analysis of quasi-static lines of force, which begin directly from their sources - charges (for electric field) and currents (for magnetic field), allowed in the proposed atomic model of the dipole to remove the restrictions of the Hertzian dipole and the standard model of the dipole and give a physical analysis of the mechanisms of formation of reactive near fields and their transformation into active radiation fields, as well as to describe the corresponding energy flows in the local zone (r ~ l0) of the oscillating atomic dipole on the qualitative level of classical electrodynamics. It has been shown for the first time that the free (active) radiation field is bom only in the phases (II and IV) of the convergence of charges + q and -q atomic dipole at the moment of detaching from them of excessive lines of force of the near field pumped in the previous phases (I and III) of the distancing from each other charges. In this case, the direction of the electric vector of the dipole, and thus the direction of the vector of the reactive energy flux, change to the opposite. Today, the processes of nanostructure organization remain topical issue of nanophysics and related branches of science (in particular, optics). In the present work it was also established that at large amplitudes of the external optical near field (for example, fiber optic nano-needles or nano-peaks of a surface of a quartz plate), it is possible to synchronize oscillations of dipoles with different resonant frequencies. The deposition for dipole nanostructures takes place in those regions where the oscillations resonate and synchronize with the optical near field. The structure of a complex nanostructure of two simpler passes in two stages. At the first stage, they are synchronized with each other. At the second stage, electrostatic forces are included in the work, attracting and reorienting structures to a position that corresponds to a minimum of total energy of the system.

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