Study On Trapping Of Multiparticlesby Tightly Focusing The Cylindrical Vector Beams

Polarization is a very important property of light. Combining beams with different polarizations with diffractive optical elements and optical configuration, a wealth of novel phenomena have been presented, thus it posseses high research value. As spatial variant polarization beams, cylindrical vector beams havegained extensive attentions as a result of its excellent focuisng properties, which hold potential applications in several aspects such as optical trapping, nanometer lithography, and particle acceleration. On the basis of the vector diffraction theory, the primary aim of this thesis is to explore the tightly focusing field distributions of the cylindrical vector beams by using modulation of diffractive optical element, realizing optical cage a nd one-dimensional optical chain. Further, in view of Rayleigh scattering theory, we quantitively dissect the radiation force of particles exerted by optical field, as well as discuss stable condition of particle trapping. The main content is as follows:Based on the vector diffraction theory, we deduce the tigthly focuisng field distributions of the cylindrical vector beams. Especially, the analytical fomulas on the light field of both the radially and azimuthally polarized beams are given. Additionally, we calculate the radiation force exerted on Rayleig particles by tightly focused field of the cylindrical vector beams, giving two kinds of stable criteria for particle trapping.Firstly, we calculate the normalized intensity distributions of tightly focusing double-ring shaped cylindrial vector beam. The peak inetenity as a function of truncation parameters is manifested, and the well-defined physical machanism is analyzed accordingly. Subsequently, we dissect the depedence of tigthly focuisng field distributions on the angle between polarized direction and raidal orientation. as a typical demonstation, tightly focuisng fields are calculated under either the pure radial illumination or pure azimuthal illumination. On the basis of the Rayleigh scattering theory, we further present the gradient force, scattering and absorption forces of Rayleigh particles in the tightly focused field, still, several stable criteria for particle trapping are illustrated.On the basis of the vector diffraction theory, combined with optical vortex and the interaction of polarization aberration, we calculate the tightly focused light field which ia produced by cylindrical vector beams modulated by three-ring shaped aperture, and analyse the physical mechanism of optical chain. We study the influence produced by the phase change betwwen the inner ring and outer ring to the optical field distribution. Based on the Rayleigh scattering theory, we calculate the gradient force, scattering and absorption force of Rayleigh particles in the tightly focused light field by the azimuthally polarized light, still, we calculate the stability criterion of particle capture.In order to further optimize the stability of the particle capture, we calculate the light intensity distribution which is focused by the radial polarized light modulated by a three-ring shaped aperture. We study the influence produced by the phase change betwwen the inner ring and outer ring to the optical field distribution.On the basis of the Rayleigh scattering theory, we calculate the gradient force, scattering and absorption force of Rayleigh particles in the tightly focused light field by the radially polarized light, we compare the stability of the particle capture in the light field focused by radially polarized beams and azimuthally polarized beams, and study the physical mechanism that radially polarized light is better than azimuthally polarized light.