Structure of Twisted States in Ferroelectric Liquid Crystals Studied by Microspectrophotometry and Numerical Calculations

The transmittance spectra of twisted states of surface stabilized ferroelectric liquid crystal cells were measured under a polarizing optical microscope. It was found that the two twisted states give different spectra, as expected by an apparent color difference. There were two cases; in one case the two spectra interchange by rotating a cell, while in the other case the two spectra do not interchange. We could simulate both cases by numerical calculations of the spectra using a smectic layer bend model. The spectral interchange could be analytically explained on the basis of the Jones retardation matrix method. A simple method for judging the condition of the interchange is proposed.