Holographic grating in methyl red-doped polymer dispersed liquid crystals
Abstract
Optical recording and the development of suitable recording media has become a subject of extensive research in the past decade. Applications in the field of optical processing and data storage have given rise to such interest. Most notable in the field of new materials for optical recording are photorefractive crystals, polymeric liquid crystals and doped nematics. In this paper, we present yet another candidate for a holographic material based on dye-doped polymer dispersed liquid crystals (PDLC).
Dye-doped PDLCs have been attracting attention in the field of holographic storage. In Opt. Commun. 150, 297 (1998), holographic storage was done on dye-doped PDLCs fabricated via the polymerization induced phase separation (PIPS) technique. The PDLC system used was based on a UV curable epoxy resin and liquid crystal E7 doped with the azo dye D2 and D37. They concluded that a space-charge field is responsible for the grating they observed. This is characteristic of gratings formed by the photorefractive effect. Others have also reported holographic grating formation with an E7 based PDLC. To our knowledge, holographic storage beyond the E7 PDLC system is still untried. In this paper we present initial results on the writing of permanent holographic gratings on a new dye-doped PDLC system fabricated via a different phase separation technique compared to the references. We used the knowledge from the references to produce gratings on the new PDLC system, which we guarantee to be a holographic material, as we will soon see from the discussions.