Vorschau

PDF, Englisch Download (22MB) | Nutzungsbedingungen

Abstract

Physics of vortex beams is a new, fast developing research field that covers diverse topics, such as optics, quantum information, materials science. Vortex beams are known to carry well-defined orbital angular momentum along their propagation direction that gives rise to their helical wavefronts. Such twisted beams of light and electrons have been discovered both theoretically and experimentally in the beginning of 1990s and in the end of 2000s, respectively. In this thesis, we put the emphasis on a special type of vortex beams, called Bessel beams, and present a theoretical study for twisted matter waves, such as electrons and atoms, that are driven by a laser. First, in order to examine the interaction of relativistic electron vortex beams (EVBs) with a laser light we obtain exact analytical solutions for Dirac equation by generalizing recently constructed (field-)free EVBs. To do so, we superimpose a multitude of Dirac-Volkov wave functions with well-defined amplitudes that correspond to the monoenergetic distribution of electrons in vortex beams with non-zero orbital angular momentum. Second, we extend our study of EVBs to another type of matter waves and produce Bessel beams of two-level atoms that resonantly interact with a laser light. Moreover, we demonstrate that the profiles of both the laser-driven electron and atomic vortex beams obtain a non-trivial, Bessel-squared-type behavior. We take a snapshot of these profiles and show that we are able to control and manipulate the intensity distribution of beams by tuning the laser field.