We consider conditions of structural stability under which the array of singular beams preserves its topological structure and intensity distribution while slightly perturbing its intrinsic parameters. The orbital angular momentum of the array as a function of the array parameters is a characteristic function, and its extreme points correspond to stable and unstable array states.
© 2008 Optical Society of America
Lasers and Laser Optics
Original Manuscript: July 23, 2007
Revised Manuscript: October 24, 2007
Manuscript Accepted: October 25, 2007
Published: December 19, 2007
Yana Izdebskaya, Vladlen Shvedov, and Alexander Volyar, "Symmetric array of off-axis singular beams: spiral beams and their critical points," J. Opt. Soc. Am. A 25, 171-181 (2008)