Open AccessDetermining topological charge of an optical beam using a wedged optical flat
Author(s) -
Behzad Khajavi,
Enrique J. Galvez
Publication year - 2017
Publication title -
optics letters/optics index
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.524
H-Index - 272
eISSN - 1071-2763
pISSN - 0146-9592
DOI - 10.1364/ol.42.001516
Subject(s) - topological quantum number , optics , physics , wavefront , optical vortex , light beam , angular momentum , interferometry , shearing (physics) , beam (structure) , curvature , planar , azimuth , topology (electrical circuits) , geometry , classical mechanics , quantum mechanics , mathematics , computer graphics (images) , combinatorics , computer science , thermodynamics
The topological charge of a beam carrying an optical vortex is an important parameter that specifies the amount of orbital angular momentum carried by the beam and the azimuthal order of the beam mode. We present an experimental method to determine the sign and magnitude of the topological charge using a wedged optical flat as a lateral shearing interferometer. When the curvature of the wavefront is adjusted to be planar, the fringe pattern generated by the shearing interferometer consists of two conjoined forks that unambiguously identify the topological charge of the beam. We also investigated the changes in the pattern when the wedged flat is rotated.