Ion-beam-processed SiO2 film for homogeneous liquid crystal alignment

Liquid crystals in our experiments could be aligned on a SiO2 surface bombarded by a neutral argon ion beam of an appropriate energy. Also, the pretilt angle of liquid crystals could be varied between 0 and 3.5 degrees, by controlling the argon ion beam with an energy of 500 eV at an incident angle varying from 0 to 85 degrees that was measured from the normal of the substrate. Finally, the twist nematic test cell of the 6 mu m cell gap incorporating SiO2 alignment films exhibited a high optical transmission and a fast response time when the angle of the incident ion beam was more than 45 degrees.