Features of IR holograms recorded on polyvinyl alcohol films

Controlled diffraction liquid-crystal structures with a photoalignment polymer

“…Controllable diffraction elements of various types based on LCs have been developed and different methods of grating formation have been proposed. In early systems [4,5], the diffraction was controlled using optoelectronic structures of the LC-relief grating type, where the initial LC director orientation was set mechanically, by rubbing a poly(vinyl alcohol) (PVA) layer. Reorientation of the LC director under the action of an applied electric field led to a change in the depth of modulation of the refractive index and, hence, in the diffraction efficiency of the LC grating.…”