We consider optical propagation through a centrosymmetric photorefractive crystal with the externally applied bias voltage modulated along the optical propagation direction. We analytically prove that, if the modulation scale is smaller than the optical diffraction length, the resulting effective nonlinearity has an even parity in the transverse plane for an even-symmetric intensity profile and supports bending-free solitons down to few-micrometer beam widths. Numerical integration of the full photorefractive model for light–matter interaction allows us to confirm the feasibility of these miniaturized solitons and, for longer modulation periods, to investigate the excitation of self-trapped wiggling optical beams.
© 2008 Optical Society of America
Original Manuscript: April 29, 2008
Revised Manuscript: July 7, 2008
Manuscript Accepted: July 23, 2008
Published: September 11, 2008
Alessandro Ciattoni, Eugenio DelRe, Carlo Rizza, and Andrea Marini, "Miniaturized bending-free solitons by restoring symmetry in periodically biased photorefractives," Opt. Lett. 33, 2110-2112 (2008)