Optical circuitry in photorefractive strontium barium niobate

Summary form only given. Optical spatial solitons in photorefractive crystals have shown the potential to form optical circuitry by forming graded index waveguides which can guide other beams. A soliton forms when a photoinduced index change in the material exactly compensates for the diffraction of the beam; i.e. the beam creates its own waveguide. In photorefractive materials, a screening soliton is formed by applying an external electric field that within the incident light beam is screened by photoinduced charges. The external field then lowers the refractive index around the screened area, via the Pockels effect, creating a waveguide. However, these induced waveguides disappear if the applied field is removed from the material. In the paper we report on the use of soliton formation to create permanent waveguides by selectively reorienting ferroelectric domains within the incident light beam.