Matrix optics approach for liquid crystalline blue phases

Liquid crystalline blue phases (LCBP) and their diffraction patterns were investigated experimentally and theoretically. We measured the diffraction pattern for different wavelengths of monochromatic light with the help of a conoscopic setup of a polarization microscope. Moreover, the diffraction patterns of LCBP and dye-doped LCBP were calculated with the help of a 4×4 matrix method which allows amplitude and phase investigations. It was found that such a matrix method is well suited to simulate optical properties including Bragg diffraction of anisotropic three-dimensional structures with periods below visible light wavelength. We calculated complete Kossel diagrams and compared them with measurements. A contrast inversion phenomenon for Kossel diagrams of LCBP incorporating an anisotropic dye was analyzed.