Comparative study of liquid crystal variable retarder with rubbed polyimide and SiO2 thin films by glancing angle deposition

A comparative study on the optical, morphological and laser-induced damage characteristics of rubbed polyimide, SiO2 thin films by glancing angle deposition, and the corresponding liquid crystal (LC) retarders, is presented in this paper. SiO2 inorganic thin films were prepared with a deposition angle of 45 degrees, and traditional polyimide (PI) films were prepared by spin coating and rubbing. The experimental results indicate that the SiO2 thin films have a good transmittance and resistance to laser damage. The transmittance of the SiO2 thin films was above 92% in the wavelength range 400-1200 nm, and that of the corresponding LC retarder was approximately 90% in the wavelength range 800-1200 nm. The laser-induced damage threshold of the SiO2 thin films reached 32.6 J/cm(2), and that of the corresponding LC retarder was 1.84 J/cm(2). These results are better than those of the PI alignment films. SiO2 thin films have potential for use in the LC optical devices for laser applications.