OAM beam generation in space and its applications: A review

In recent years, vortex beams with orbital angular momentum (OAM) have attracted more and more attention. The wavefront of the OAM beams is helical, the intensity at the center of the beam is zero, and there is a phase singularity. Because of the novel phase characteristics of OAM beams, they have a wide application prospect in the fields of optical communication, rotating body detection and particle manipulation. Therefore, the research on the generation technology of OAM beams and their application range are of instructive significance to the future experiments. In this paper, the common beams carrying OAM are introduced, and the techniques of generating OAM beams in free space are summarized, including intracavity conversion method and extracavity conversion method. The application range of OAM beams studied at present is discussed, and the development trend of OAM beams is prospected. The purpose of this paper is to provide reference and guidance for related experiments of OAM beams in the future.