Photoresponsive self-assembled monolayer/photopolymer film for optical information storage using liquid crystals

Ultrathin films of alkoxy alkyl amino silanes functionalised with photochromophore moieties have been grown on glass and quartz substrates by self-assembly (SA) techniques. The films have been selectively photodimerised with polarised UV light using photomasking to produce anisotropic ordered structures locally. These ordered structures produce uniform planar orientation of nematic liquid crystals. Liquid crystals being birefringent (Δn=≈0.10-0.25), a high optical contrast is produced between uniformly aligned and non-aligned regions when viewed between crossed polarisers. This has given rise to the possibility of creating a new type of optical storage liquid crystal display. It has been possible to store line patterns with a line resolution of ≈20 μm by this technique. Such films can be used to record holographic gratings using UV polarised light.