Measurement of the Mueller matrices of blue-phase structures

Abstract

Using polarized light scattered at 45\ifmmode^\circ\else\textdegree\fi{} from mixtures of chiral CB15 and nonchiral E9 liquid crystals, we have measured the Mueller matrices characterizing the Bragg reflections of blue-phase structures BPI, BPIIA, and BPIIB. Surprisingly, all of these structures possess essentially the same Mueller matrix, namely, that of an elliptical polarizer with axial ratio \ensuremath{\cong}0.7. The implications of the results on the allowed space groups of the blue phases is discussed in the context of the theory of Hornreich and Shtrikman.