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Chinese Optics Letters, Vol. 17, Issue 9, 090604 (2019)

Misalignment measurement of optical vortex beam in free space

Xin Yang1, Shibiao Wei2, Shanshan Kou3, Fei Yuan1, and En Cheng1,*

Author Affiliations

  • 1Key Laboratory of Underwater Acoustic Communication and Marine Information Technology, Ministry of Education, Xiamen University, Xiamen 361005, China
  • 2Centre for Micro-Photonics, Faculty of Engineering, Science and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
  • 3Department of Chemistry and Physics, La Trobe Institute for Molecular Science (LIMS), La Trobe University, Melbourne, VIC 3086, Australia

Abstract

The misalignment of optical vortex (OV) beams, including transversal displacement and tilt, occurs in many situations, including on reflection or refraction at an interface between two different media and in propagation and tracking systems for optical communications. We propose a reliable method to determine and subsequently eliminate tilt and transversal displacement in an OV beam. An experimental setup was established to verify the proposed method, and the experimental results showed good agreement with those of the numerical simulations. Using the measured misalignments, the initial orbital angular momentum spectrum can be recovered in free space.