| 摘要 |
PURPOSE:To obtain a secondary organic nonlinear optical element having high nonlinear optical effect by using a crystalline material of a specified compd. having secondary nonlinear optical effect. CONSTITUTION:A crystalline material having secondary nonlinear optical effect expressed by the formula is used. In the formula, each X, Y, and Z is an org. substituent, at least one of them is electron attractive group; D<1>-D<5> are org. substituents, at least one of them is electron donative group. It is preferred that D<3> among D<1>-D<5> is an electron donative group, and the others are H atoms. Further, X is desirably an H atom, Y and Z are desirably electron attractive groups such as CN-, or esterified carboxy group, etc. Further, D<3> is pref. (mono- or di-)amino group, etc. Such compds. are constituted of a styrene skeleton of a large conjugated system having an electron donative group and an electron attractive group in the molecule, providing therefore a large amt. of electrons movable by the electric field caused optically. Accordingly, a great nonlinear effect is obtd. By this constitution, secondary higher harmonics of high intensity can be isolated even with weak laser light. Also, electro-optic effect can be exhibited even at slight change of electric voltage. |
