Refractive index variation in radiation-sensitive matl. - contg. photolysable cpd., for optical structure prodn

The refractive index variation is produced by exposing cpd(s) undergoing photolysis to radiation with at least enough energy to cause the said reaction. The cpd. pref. is an org. halogen cpd. esp. C2H2Br3OH, which is incorporated in a (polymeric) binder (polymethyl methacrylate) in an amt. of 200-10 (60-20) wt. %. It is used in the form of a thin (0.5-20, pref. 1-10 um) film, opt. on a transparent base, and contains a sensitiser. The method can be utilised for optical data storage, prodn. of phase lattices or phase holograms and for making optical elements, e.g. light-conducting fibres, taper or wholly integrated optical circuits, directly in the film e.g. using the photomask technique. High resoln. extremely accurate structuring, economy and high packing density for recording information are obtained.