Multistage optical memory of a liquid crystal diffraction grating in a single beam rewriting scheme

The authors report on the multistage optical memory of a liquid crystal (LC) diffraction grating fabricated using a dye-dispersed LC/polymer composite medium. Under a single pump beam, the reorientation of dye molecules, confined within spatially periodic interpolymer networks produced by a patterned exposure of ultraviolet light, allows for a pure optic-axis modulation which gives high diffraction efficiency in a planar LC configuration. The resultant multistage optical memory of the LC grating is controlled solely by the polarization state of a single rewriting beam without the use of an erasing step prior to every rewriting process.