Dye-doped glasses: nonlinear optical material for spatial soliton applications

Spatial solitons are light beams that propagate with a constant transverse profile as a consequence of an exact balance between diffraction and self focusing effects. Such beams hold great promise for applications such as optical interconnects, optical switching, and steerable optical waveguides. However, the generation of spatial optical solitons places especially stringent constraints on the material properties of the nonlinear optical material used to support the propagation of the solitons. In addition to the usual requirements that the nonlinear optical material possess a large nonlinear susceptibility and low attenuation losses, materials suitable for the propagation of spatial solitons in two transverse spatial dimensions must possess additional properties to render the soliton stable against collapse. Several methods have been proposed to render the propagation of solitons stable. These include the use of a saturating optical nonlinearity, the use of photorefractive materials, or the use of cascaded optical nonlinearities. In our work, we have concentrated on the development of materials with a saturating optical nonlinearity, that is, a material for which the change in refractive index induced by a material of intensity I is described by the equation Δn=n₂I/(1+I/I _sat). We report that acridine-doped lead tin fluorophosphate glass is a promising nonlinear optical material for use in the study of spatial solitons