We present an analysis of the effect of torsion stresses on the spatial distribution of optical birefringence in crystals of different point symmetry groups. The symmetry requirements needed so that the optical beam carries dislocations of the phase front are evaluated for the case when the crystals are twisted and the beam closely corresponds to a plane wave. It is shown that the torsion stresses can produce screw-edge, pure screw, or pure edge dislocations of the phase front in the crystals belonging to cubic and trigonal systems. The conditions for appearance of canonical and noncanonical vortices in the conditions of crystal torsion are analyzed.
© 2011 Optical Society of America
Original Manuscript: March 18, 2011
Revised Manuscript: April 26, 2011
Manuscript Accepted: May 5, 2011
Published: June 3, 2011
Ihor Skab, Yurij Vasylkiv, Bohdan Zapeka, Viktoriya Savaryn, and Rostyslav Vlokh, "Appearance of singularities of optical fields under torsion of crystals containing threefold symmetry axes," J. Opt. Soc. Am. A 28, 1331-1340 (2011)