Study On The Transmission Characteristics Of A New Type Of Anomalous Vortex Beams

Vortex beam since it has been discovered, its many characteristics caused widespread concern of researchers. Vortex beam is a kind of special beam with helical phase wavefront, the phase distribution function often contain spiral phase factor exp(ilθ) that is proportionate to rotation azimuth angle θ. The vortex beams have phase singularities, when propagating, which form dark hollow vortex spot in the center of its intensity. In 1992, Allen et al. demonstrated that optical vortex with a phase factor exp(ilθ) with orbital angular momentum in the paraxial propagation conditions. Further study of the vortex beam will greatly promote the development of science and Application Research of our country in the field of optical micromanipulation, optical information transmission, nonlinear optics, optical waveguide laser, particle, biomedical, atom optics and molecular optical.This thesis first gave a brief introduction to the optical vortex, and the commonly used methods to generate optical vortex are introduced, the thesis focuses on the research of the transmission characteristics of new anomalous vortex beam propagating in free space and random medium. The main contents are as follows:1. The first chapter gives a simple summary of the development history and research status of optical vortices, and then summarizes the application of optical vortices.2. The orbital angular momentum theory of the optical vortex under paraxial approximation are introduced. The typical method of optical vortex generated are introduced, which are the geometric mode conversion method, spiral phase plate method, hologram method, liquid crystal spatial light modulator.3. Study on the transmission characteristics of anomalous vortex beam through the annular aperture in free space. The transmission theory of laser beam and research methods are introduced, mainly on the evolution of Collins integral form of description theory and matrix method. Then, the basic characteristics of the anomalous vortex beams are studied, numerical simulation of the intensity distribution and phase distribution of the beam, and analyzed the law. Finally, the main research on the transmission characteristics of anomalous vortex beams through paraxial ABCD optical system with an annular aperture in free space. By changing the parameters of the beam and the aperture radius, and then analysis theintensity distribution of the spot characteristics of anomalous vortex beam.4. Study on the transmission characteristics of anomalous vortex beams in a turbulent atmosphere. Firstly, atmospheric turbulence profiles are described. Then, analyzes the atmospheric structure constant of refractive index of the atmospheric turbulence models, summarizes the characterization of atmospheric structure constant of refractive index changes, and describes the various models of power spectrum analysis of the atmospheric turbulence, the scintillation index of atmospheric turbulence. Finally, the anomalous vortex beams are numerically derived in the theoretical model of turbulence, the transmission characteristics of anomalous vortex beams are studied. By changing the parameters of atmospheric turbulence, numerical simulation of the intensity distribution and analysis the beam intensity distribution.