نبذة مختصرة : Optical Vortex (OV) is main object under study in this thesis. Light beam carrying OV has helical wavefront, zero intensity, and undefined phase at vortex location. • OVs have found applications in various areas: data inscription, beyond diffraction limit resolution microscopy, etc. For most of those applications broadband OVs are desired. Thus, in first part of dissertation a method for effective generation of high contrast OV over wide spectral range has been developed. It is based on polarization selective filtering of the beam passed nano structured Swaveplate. Proposed filtering can be applied for achromatic vortex generator based on geometric phase retardation, e.g. liquid crystal q-plate or photonic crystal. • Second part is devoted to nonlinear transformations of OVs. o Firstly, for the first time, generation of THz vortex wave from air plasma is under investigation. Plasma filament is excited by bichromatic OV fs-laser pulses. THz vortex wave will open up for new possibilities in emerging THz spectroscopic applications. o Secondly, a method for generation of high power radially polarized beams was developed. Proposed method employs optical parametric amplification and superposition of two OVs of opposite handedness of helical wavefronts and circular polarizations. This method has high practical importance in laser material processing. • In the last part it is shown for the first time that a non-birefringent particle can be controllably spun while optically trapped in OV beam. Since most of the natural particles are non-birefringent it is anticipated that the developed method will find wide applications and extend abilities of optical tweezers.
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