We have produced beams with dark rings and studied their propagation through photovoltaic photorefractive media. We observe that dark rings, instead of forming dark ring solitons, break into vortex–antivortex pairs, forming quadrupoles. The experimental results could be taken as a consequence of modulational instability during beam propagation that is revealed through our numerical analysis.
© 2012 Optical Society of America
Original Manuscript: April 16, 2012
Revised Manuscript: June 5, 2012
Manuscript Accepted: June 16, 2012
Published: July 20, 2012
Pravin Vaity and Ravindra Pratap Singh, "Generation of quadrupoles through instability of dark rings in photorefractive media," J. Opt. Soc. Am. B 29, 2099-2102 (2012)