Investigation On Conical Diffraction Characteristics Of Anomalous Vortex Beam

The phenomenon of conical diffraction of biaxial crystals was discovered in the 19 th century.With the rapid development of laser technology and the emergence of advanced synthetic crystal technology,people have aroused new interest in the phenomenon of conical diffraction of biaxial crystals and conducted a lot of research,which has greatly expanded the potential application field of conical diffraction.The main content of this paper consists of three parts.Firstly,the characteristics of the conical diffraction field of anomalous vortex beams passing through an achiral biaxial crystal are analyzed.Based on the theory of conical refraction diffraction,the mathematical expression of the light field of anomalous vortex beam after passing through biaxial crystal is given.Through numerical simulation,the effects of the ratio of ring radius and beam waist radius,beam order,topological charge number and propagation distance on the propagation characteristics were investigated.The results show that the light field of the anomalous vortex beam is different from the double-ring pattern of the Gaussian beam,and the light field is a multi-ring pattern at the focal plane when the ring radius of conical refraction is much larger than the beam waist radius.With the topological change number increasing,the number of bright rings increases at the focal plane.secondly,The evolution of anomalous vortex beams with different polarization states from conical diffraction to birefringence is also discussed.The influences of the propagation distance and the inclination of the propagation direction of the incident beam with respect to the optical axis on the transmission characteristics of circular,linear and elliptical anomalous vortex beams are analyzed.The conical diffraction characteristics of elliptically polarized anomalous vortex beams are discussed when the phase difference of two perpendicular polarized beams is changed.The results show that in the evolution from conical diffraction to birefringence,the intensity distribution of circularly polarized anomalous vortex beam is more sensitive to the tilt factor than that of circularly polarized gaussian beam.Finally,the conical diffraction of anomalous vortex beams through chiral crystals is studied,and the influence of the ratio of conical diffraction ring radius to beam waist radius on conical diffraction is discussed.The study of conical diffraction of anomalous vortex beam will enrich the research content of conical diffraction and provide theoretical guidance for the relevant experimental research...