Abstract

We report on a new laser-induced thermal effect in nematic liquid crystal films containing dichroic dyes. It was observed that focussing a laser beam onto thin (20 μm) homeotropic layers of the nematic at a threshold incidence power (milliwatts) a disclination loop forms. Figures 1 and 2 show far and near field characteristics of transmitted beam due to formation of these loops. The formation of these loops is reversible, ie. reducing the laser input power they disappear. In the presence of an external electric field (30 V) a narrow bistable region was found with switching times of the order of milliseconds (see figure 3).

© 1985 Optical Society of America