Coexisting Nematic and Smectic- A Phases in a Twisted Liquid-Crystal Cell
Osipov, M. A.
Sambles, J. Roy
University of Exeter; University of Strathclyde
Physical Review Letters
American Physical Society
Twisted homogeneously planar-aligned nematic liquid-crystal cells are cooled into the smectic- A phase. The expected defective structure does not form. Instead the cells still show good optical-guiding characteristics. Exploration of the cells using a half-leaky guided-mode arrangement reveals that the liquid-crystal phase separates into three or more regions. Adjacent to both the upper and lower boundaries is a region of highly twisted nematic liquid crystal. In the center of the cell is one or more homogeneous smectic- A regions with smectic layers normal to the cell surfaces, separated by twisted nematic. As the cell is cooled so the smectic- A regions grow in thickness with the nematic regions progressively thinning but with increased twist gradient. A theoretical model of these novel results is presented.
Lizhen Ruan, M. A. Osipov, and J. Roy Sambles, Physical Review Letters, Vol. 86, pp. 4548 - 4551 (2001). "Copyright © 2001 by the American Physical Society."
86 (20), pp. 4548-4551