Bistable phase locking of laser-like systems via rocking: Transforming optical vortices into phase domain walls

By laser-like we refer to optical systems that, like the laser, exhibit phase invariance, non-degenerate optical parametric oscillators or two-wave mixing photorefractive oscillators (TW-PRO) among them. The positive answer is given by a new type of forcing that receives the name of rocking, which, in optics, consists in the optical injection of an almost resonant, amplitude modulated plane wave (in the simplest case, a bichromatic injection) into the laser(like) cavity. When the rocking parameters (carrier frequency, and modulation frequency and amplitude) are properly tuned laser emission frequency locks to the carrier frequency and its phase displays bistability between two opposite values.