MATERIALS EXHIBITING LARGE NON LINEAR OPTICAL PROPERTIES

摘要

Classes of materials suitable for the construction of devices which can be switched under the influence of an applied optical field (exploiting non linear susceptibility of the material) are described. Essentially such materials comprise a nematic polymer liquid crystal molecule which exhibits a very high degree of polar order for a given poling electric field, and comprises long rod-like monomers having a high non linear dielectric susceptibility which cooperate to act as one large dipole in the poling field. Both side chain (comb) and main chain (worm) polymer liquid crystals can be employed. A polymethacrylate with a nematic aromatic ester side chain is one class of a side chain polymer having the desired switching characteristic. Worm polymers having the desired switching characteristics are found inter alia among the aliphatic/aromatic polyimides.