Patterned optical properties in photopolymerized surface-aligned liquid-crystal films

MOST practical applications of liquid crystals require control of molecular alignment at macroscopic scales1. This is achieved most simply by confining the liquid-crystalline phase between mechanically rubbed surfaces1. Recent developments2–11 have shown that liquid-crystal alignment can also be controlled by optical means: for example, if azo dyes either on the alignment surface2,3,5,8–11 or dispersed within the liquid crystal itself4,6,7 are oriented by illumination with polarized light, alignment can be induced in the liquid crystal. We show here that the high-resolution alignment patterns obtainable by such techniques may be 'frozen in' by subsequent photopolymerization of the optically patterned liquid-crystalline phase. The resulting polymer films might prove valuable in the development of high-density optical storage media, three-dimensional stereo displays and other optical devices.