The Study On The Orbitalangular Momentum Of Vortex Beam

Vortex beam is a laser beam with the center of the light intensity and the propagation of the spiral wave. Due to its unique phase morphology and physical properties, in the field of laser catheter, optical tweezers, optical communication system, quantum communication and are widely used. Therefore, the research on the various characteristics of the vortex beam, and how to obtain the high quality vortex beam through the experiment has become a hot research topic at home and abroad. The main contents of this paper are as follows:Firstly, The research background, the present situation and the basic principle to optical vortices are described. Mathematical expressions of optical vortices, the method of generating vortex beams, the characteristics of the orbital angular momentum of the vortex beam and its characteristics in the near field are introduced.Secondly, using single slit diffraction and double slit interference theory of vortex beam orbital angular momentum are studied, mainly for fractional orbital angular momentum vortex beams. Through the different image features analyze the different topological charge number. In the single slit diffraction conditions, except the orbital angular momentum of the topological charge number, factors affecting the distribution of light intensity pattern also includes spot size and diffraction plane distance receiving screen distance and width of single slit. 1 vortex beams are generated by using the spiral phase plate, and the influence factors of the single slit diffraction pattern are studied. By using the double slit interference theory, the characteristics of the vortex beam of the orbital angular momentum of the fractional order and the integer order are studied. The numerical simulation and analysis are carried out by MATLAB, and the relevant experimental verification is carried out.Finally, several methods of generating vortex beams are compared and analyzed,focusing on the propagation characteristics of SLM, and the relationship between the propagation distance and the load intensity is given.