Reshaping of the refractive index profile of a liquid crystal waveguide by means of an external electric field

Graded index planar waveguides have been realized by using a nematic liquid crystal in a distorted hybrid configuration. The application of external electric fields enables to modify the orientation of the local molecular axis and hence to reshape in an easy and controlled way the refractive index profile. The waveguide, characterized for various electric field strengths by means of m-lines spectroscopy, behaves in good agreement with what expected from a simple model based on the dielectric, optical and elastic properties of the liquid crystal.