Spherical fields as nonparaxial accelerating waves
  We introduce nonparaxial spatially accelerating waves whose two-dimensional transverse profiles propagate along semicircular trajectories while approximately preserving their shape. We derive these waves by considering imaginary displacements on spherical fields, leading to simple closed-form expressions. The structure of these waves also allows the closed-form description of pulses. 
Miguel A. Alonso and Miguel A. Bandres
physics.optics cond-mat.mes-hall math-ph math.MP physics.class-ph