Transformation of Optical Vortex Beams by Holograms with Embedded Phase Singularity

Abstract

Spatial characteristics of diffracted beams produced by the "fork" holograms from incident circular Lauerre-Gaussian modes are studied theoretically. The complex amplitude distribution of a diffracted beam is described by models of the Kummer beam or of the hypergeometric-Gaussian beam. Physically, in most cases its structure is formed under the influence of the divergent spherical wave originating from the discontinuity in the beam spatial profile or its derivatives caused by the hologram's groove bifurcation. Presence of this wave is manifested by the ripple structure in the near-field diffracted beam profiles and in the power-law amplitude decay at the beam periphery. Conditions when the divergent wave is not excited are discussed. The diffracted beam carries a screw wavefront dislocation (optical vortex) whose order equals to algebraic sum of the incident beam azimuthal index and the topological charge of the singularity imparted by the hologram. The input beam singularity can be healed when the above sum is zero. In such cases the diffracted beam can provide better energy concentration in the central intensity peak than the Gaussian beam whose initial distribution coincides with the Gaussian envelope of the incident beam. Applications are possible for generation of optical-vortex beams with prescribed properties and for analyzing the optical-vortex beams in problems of information processing.

12 pages, 5 figures

References in corpus (6)

• Optical spin-to-orbital angular momentum conversion in inhomogeneous anisotropic media
• Hypergeometric-Gaussian Modes
• Efficient generation and sorting of orbital angular momentum eigenmodes of light by thermally tuned q-plates
• Universal unitary gate for single-photon spinorbit four-dimensional states
• Structure of optical vortices produced by holographic gratings with "fork" geometry: Kummer beams
• High-angle diffraction of a Gaussian beam by the grating with embedded phase singularity

Cited by in corpus (7)

• Measuring the orbital angular momentum of electron vortex beams using a forked grating
• Shaping Laguerre-Gaussian laser modes with binary gratings using a Digital Micromirror Device
• Effects of misalignments in the optical vortex transformation performed by holograms with embedded phase singularity
• Fraunhofer diffraction of a Laguerre-Gaussian laser beam by fork-shaped grating
• Localization and migration of phase singularities in the edge-diffracted optical-vortex beams
• Generation of optical vortex light beams by volume holograms with embedded phase singularity
• Transformation of the singular skeleton in optical-vortex beams diffracted by a rectilinear phase step