Laser generated soliton waveguides in photorefractive crystals

Non-linear photo-excited processes using the photorefractive effect are revisited with emphasis on spatial soliton generation in special laser beam propagation conditions. The soliton beams can create reversible or irreversible single-mode waveguides in the propagating materials. The important features are the 3D orientation and graded index profile matched to the laser fundamental mode. Bright spatial solitons are theoretically demonstrated and experimentally observed for the propagation of c.w. and pulsed femtosecond laser beams in photorefractive materials such as Bi12 SiO20 (BSO) and lithium niobate crystals. Applications in high coupling efficiency, adaptive optical interconnections and photonic crystal production are possible.