Diffraction with second-harmonic generation for the formation of self-guided or 'solitary' waves

摘要

Diffraction occurring during free propagation of a beam finite in its transverse plane tends to widen the beam lateral extension and, whenever its characteristic length exceeds the propagation distance, will weaken its intensity and ability to spatially resolve a given area or spot. Propagatio nin optical waveguides is generally considered as the most effective approach for counterbalancing diffraction over finite propagation distances, utilizing a geometrical resonance occurring in configurations with media of different optical parameters.~1