Hologram Optimisation Using Liquid Crystal Modelling

ABSTRACT Beam steering liquid crystal devices employed in telecommunication networks suffer from high crosstalk. This is due to the limited resolution arising from the finite extent of the liquid crystal elastic deformation and the electric field fringing. In this paper we show how non-periodic phase elements (holograms) can reduce crosstalk. A new model is devised to evaluate the approximate liquid crystal phase profile that is many times faster than the finite element method, enabling its evaluation millions of times as it is required by the hologram iterative design algorithms. Holograms designed using the new model had improved performance and flexibility compared to periodic gratings.