Stable oscillating nonlinear beams in   square-wave-biased-photorefractives
  We demonstrate experimentally that in a centrosymmetric paraelectric non-stationary boundary conditions can dynamically halt the intrinsic instability of quasi-steady-state photorefractive self-trapping, driving beam evolution into a stable oscillating two-soliton-state configuration. 
G.M. Tosi-Beleffi (1 and 2), M.Presi (1), C. Palma (2), D. Boschi (2),   E. DelRe (1 and 3), and A.J. Agranat (4) ((1) Fonda...