With interfering illumination of Ar++ laser beams (488 nm),surface relief gratings (SRGs) were photo-inscribed on epoxy-based azo polymer (BP-AZ-CN) films.The modulation depth was about 160 nm and the spatial period was about 670 nm.The quartz slides covered with SRG films were assembled to liquid crystal (LC) cell to study the LC alignment behavior.Homogeneous liquid crystal alignment was observed in the surface relief gratings regions of the LC cell.Alignment of LC molecules was monitored by measuring the transmittance passing through the cell between crossed polarizers as a function of the angle of the cell rotating around the experiment optical axis.The transmittance changed periodically with a regular 90° separation of the rotational angle and the pretilt angle of the cell was found to be 3.2°.This alignment technique could have useful applications in the future LC displays.
