Birefringence patterns of nematic droplets

Birefringence patterns of nematic liquid crystalline droplets are investigated both theoretically and experimentally. Gridding method is developed to calculate optical birefringence patterns of nematic droplets with different director configurations. Series of birefringence patterns of the four typical nematic droplets (radial, bipolar, axial and equatorial) with different orientations of droplets' axes are obtained. By comparing experimental polarizing photographs with theoretical birefringence patterns, the authors find out that only bipolar configuration represents the self-organized structure of nematic droplets in our epoxy-based polymer dispersed liquid crystal (PDLC). It is also pointed out that the very gridding method can be easily extended to deal with other complicated anisotropic entities.