Liquid Crystalline Blue Phases - Liquid Crystalline Functional Assemblies and Their Supramolecular Structures - page 114

9
Photonics of Blue Phases
It can be expected that blue phases consisting of three-dimensional peri-
odic structures on scales equivalent to the wavelength of visible light can
be applied in photonics [40-42]. Recently, researchers have paid attention to
artificial crystals with periodic optical structures on the order of visible wave-
lengths, known as photonic crystals. Much effort has been made toward the
study and development of technologies to manufacture such crystals. Blue
phases have an edge over the top-down method of micro fabrication, since
these phases form three-dimensional photonic lattices in a self-organizing
manner. Cao et al. dispersed some fluorescent dye in BP II and activated
them with a pulsed light source and the result was lasing in three spatial
directions, proving that blue phases exhibit three-dimensional photonic char-
acteristics [43]. Yokoyama et al. used polymer-stabilized blue phases to show
that lasing from the lattice structures of blue phases takes place over a broad
temperature range of 35 K, and found that the lasing threshold and line width
are smaller than for lasing arising from a chiral nematic phase [44](Fig. 16).
Studies on the application of blue phases to photonics have in this way seen
rapid progress recently.
Fig. 16 Laser emission spectra from the polymer-stabilized blue phase of the (110)
crystal [44]
10
Electro-optics of Blue Phases
Kikuchi and coworkers found the rapid electro-optical effect in polymer-
stabilized blue phases and presented the major potential of such phases in
application to display devices and optical modulation devices [45, 46]. Tra-