Sub-Wavelength Nonlinear Accelerating Beams
  We show that optical nonlinearities allow sub-wavelength beams to propagate in circular trajectories without being attenuated in spite of their partially evanescent spectrum. Such beams are exact solutions to Maxwell's equations with Kerr or saturable nonlinearity. 
Ido Kaminer and Mordechai Segev
physics.optics cond-mat.mes-hall