Transient holographic grating in azo-dye-doped liquid crystals with off-resonant light.

Holographic gratings in nematic liquid crystals doped with Disperse Red 1 (DR1) were investigated using a linearly polarised He–Ne laser. Although the electric transitions of the samples were almost off-resonant, the diffraction of the transient holographic grating was found to exhibit a sinusoidal feature with changing the polarisation of recording beams, and the diffraction intensities and response time of the gratings were strongly dependent on DR1 concentration. The results revealed that the diffraction of holographic grating depends on the rate of trans–cis isomerisation of DR1 molecules. Moreover, the temperature dependence of diffraction indicated that the grating formation mechanism was attributed to photoinduced reorientation of photoisomerisation effect. [ABSTRACT FROM AUTHOR]