Holographic systems for recording and reading out refractive index gratings within the body of a photosensitive electro-optical material

摘要

The present invention, in order to increase the optical efficiency of holograms recorded in the body of a photosensitive electro-optical material in the form of a refractive index grating, exploits the existance, under special conditions of operation of ferro-electric materials, of non-linear relationships between the double refraction and the electric field. To this end, electric fields of different value are applied to the ferro-electric material during the recording and read-out phases. The invention applies to large capacity optical stores and also has applications in coherent optical systems employing holographic lenses.