Diffraction patterns of binary liquid crystal gratings in homeotropic and hybrid geometries

We report on the diffraction properties of the binary liquid crystal (LC) gratings consisting of alternating homeotropic and hybrid domains. The measured diffraction patterns agree well with theoretical results in a comprehensive model with a linearly approximated phase profile around the domain boundary. It is found that the linearly distorted length is independent of the grating period and depends only on the cell thickness, the surface anchoring energy, and the elastic constants of the LC material. For the LC cell thickness of 5.9 μm, the linearly distorted length is determined as 2.12 μm. The binary LC grating devices are expected to play an important role in the area of optical data storage and optical information processing.