Stable dopant for liquid crystals as materials for optically addressed spatial light modulators

It is shown that 2,6 azo-substituted anthraquinone dye-doped systems are interesting alternative to Methyl Red (MR) doped NLCs as materials for Optically Addressed Spatial Light Modulators (OASLMs) without amorphous silicon layer. Nonlinearity in liquid crystals doped with new dye is studied. Dynamic holographic grating formation is observed under conditions of low power laser light and no external fields. The samples are planar and normal incidence of light is used. The results for dynamic holographic studies are compared with azo dye MR crystals and C-60, It is shown that this dopant competes with the best known materials in terms of performance in 10 ms speed regime. The system under investigation possesses very good time stability and outstanding light fastness (even a power exceeding working light intensity 100 times is not destructive to the material). It does not form permanent component at any conditions, which is vital for applications where constant change of written information is required (OASLMs, dynamic holography, all-optical switching). Possible mechanisms and the nature of effects that lead to the photorefractive effect in the anthraquinone system are discussed. Resolution of the devices, their efficiency and optimal working conditions are investigated.