Partially erasable photoalignment layer formed in dye-doped liquid crystal films

In this study, we propose biphotonic (i.e., two-color pumping beams) erasure for partially erasing a photoalignment layer on an indium-tin-oxide (ITO)-coated glass slide resulting from adsorbed azo dye molecules doped in a liquid crystal film. The results indicate that neither of the two-color pumping beams erases the adsorbed dye layer. However, similar to 75% erasure is obtained when both two-color beams are applied simultaneously for a suitable pumping period, at suitable values of intensity ratio and relative polarization. Finally, the biphotonic erasure of a twisted nematic (TN) grating fabricated using a dye-doped liquid crystal film is demonstrated.