Manipulation And Application Of Orbital Angular Momentum In Light Field Based On Fourier Analysis

In this paper,orbital angular momentum were manipulated by Fourier transform optics,and we mainly studied the fractional spiral phase contrast imaging and the generation of chromatic orbit angular momentum beam.The spiral phase filter with integer order l = 1 can achieve the isotropic edge enhancement effect on the observed object,but the research on the fractional spiral phase contrast imaging is still relatively small.We use the phase object as the research object,and introduce the fractional spiral phase filter to study the gradual edge enhancement phenomenon.Two spatial light modulators were used in the experiment:one for displaying a phase-type pentacle object and the other for a dynamic fractional-order spiral filter.By changing the fractional vortex value Q from 0 to 1,we can observe the brightness inversion of the image edge and the background,and the selective edge enhancement phenomenon can be observed in the asymptotic enhancement of the image.The experimental results can be obtained from the digital spiral imaging principle.In addition,real-time dynamic clover edge enhancement experiments have been achieved,and our experimental results have potential applications in optical microscopy.The study of visible light communication has gradually become the hotspot of optical communication.Orbit angular momentum beam has important application in visible light communication with its special high-dimensional orbital angular momentum.We have prepared the encoded orbital angular momentum beam from non-coherent white light source and used of Theta modulation technology to extract the encoded color orbit angular momentum beam.In the experiment,we divide the spatial light modulator into four regions,the grating orientation of each region is different,and each region encodes different orbital angular momentum beam information.And then we selects the specific frequency on the Fourier spectrum plane of the 4f system.Different RGB ratio of a certain band will mix together,and in the image plane we record the color orbit angular momentum beam information.Our work may find potential application in optical information processing and visible light communication.