Generation And Propagation Study Of Fractional Optical Vortex

The fractional optical vortex is a special vortex beam, which has spiral wave fronts and intensities are zero, carries a decided orbital angular momentum. These characteristics leading vortex beam have important potential applications, including quantum information coding, particle trapping and optical tweezers, to name a few. Therefore, the fractional optical vortices become hotspots in recent years. The paper studied the following contents:Firstly, integer and fractional optical vortex and several special types of optical vortex were introduced. Several generation method of fractional optical vortex was introduced, which selected spatial light modulator as the main method.Secondly, a dove prism was inserted into a Mach-Zehnder interferometer. The magnitude of integer and fractional topological charges was quantitatively measured by using a simple unified formula. The proposed method measured topological charges can up to 90. Based on triangle aperture, the topological charges of fractional Laguerre-Gaussian(LG) beam was determined by counting the external points of the triangular array. Furthermore, we also found that the optical vortex transmitted stably in these two methods. Because of the patterns of fractional optical vortex clarity and stability, it can be stable propagate. We analyzed high-order Bessel optical vortex of fractional type by vector wave analysis of tightly focused beam. With the increase of topological charge with 0.1 order, the electric components are different.Finally, Optical vortex in the application of image processing was studied. Micro in plane displacement measurement using digital speckle correlation method based on phase vortices was proposed. We take eccentricity of core structure parameter as characteristic factor to make correlation operation. The calculation time increase at least one order of magnitude in keeping equivalent measuring accuracy.