Theoretical And Experimental Study Of Optical Vortices With Plane Beam Oblique Incidence Of Fork-shaped Grating

For ortex beam with the hollow intensity distribution and orbital angular momentumwhich can trap and manipulate micro-particles,it has been widely used in optical tweezersand optical rotation.In resent years, many researchers have designed some methods toobtain vortex beams. In these methods, the computer generated holography (CGH) isstudied more because the theory is simply and easy to realize, utilization of beam is high,and it is easy to obtain the beam with different order number that we need.So it attractsmuch attention of Academic researchers. Past research has focused on theoretical research,mostly simulation analysis. However experimental researches and comparison of theexperimental results and theoretical results are reported a few. This paper of experimentresearch about the fork-shaped grating with CGH to obtain vortex beam is to dosomething as follows:Firstly, the concept and properties of vortex beam, types of vortex beams includingLaguerre-Gaussian beams, high-order Bessel beam, local hollow beams, vortex beamarray and so on are expounds. We introduce the basic theory of vortex beam generated bythe computer-generated holographic method and the angular momentum characteristics ofvortex beam and methods of generation of vortex beam.Secondly, Theoretical calculation and simulation analysis of obtaining vortex beam usingcomputer-generated holography have been done,aiso theoretical derivation and simulationof getting vortex beam by fork-shaped grating. Then that planar light inclined incidencethe fork-shaped grating to obtain vortex beams is calculated in theory,simulated andanalysed.Finally,.We use the film to record holograms which are recorded by computer,respectively make grating of different order number including integer and fractional ordersfork-like gratings and the gratings that can generate vortex beams with two vortex cores.The experiments were designed and did to obtain vortex beam.. Also the comparing of theexperimental results and the results of theoretical simulation are detailed analysis. Then onthe above experimental phenomena appeared in the experiment, error analysis are carried out, some constructive opinions and suggestions of improvement are made to puttingforward the experimental equipment...