We suggest a new method of electrical fixing in strontium-barium niobate (SEN) crystals. The method takes advantage of the large difference of the extraordinary refractive index in poled compared to unpoled SEN samples. A SEN crystal that is locally depolarized can guide extraordinarily polarized light inside the depoled crystal areas. A local depoling of the crystal is achieved with the help of light-induced screening of an externally applied electric field. By applying a suitable external electric field, the polarization can be reversed outside the illuminated area, while the reversal inside is prevented. At the boarders between illuminated and non-illuminated regions depolarized areas can form, resulting in waveguiding channels for extraordinarily polarized light.

© 2001 Optical Society of America