We describe the principle of operation of a new class of optical devices operating in quadratic non-linear media that mix wave front topological charge dislocations nested in focused light beams and produce certain patterns of bright spatial solitons. Central to the device behaviour is the orbital angular momentum of the light beams.
Torner, L., Juan P. Torres, Petrov, D., Soto-Crespo, J. From topological charge information to sets of solitons in quadratric nonlinear media. "Optical and quantum electronics", Octubre 1998, vol. 30, núm. 7, p. 809-827.