QUADRATIC NONLINEAR OPTICAL ELEMENT.

摘要

A high-performance quadratic nonlinear optical element which can exhibit a large nonlinear optical effect. The element contains a part which comprises a non-centrosymmetric monoclinic crystal, belonging to the space group Cc and the point group #9, of 4'-nitrobenzylidene-3-alkanoylamino-4-methoxyaniline of formula (I) or derivatives thereof wherein at least part of the hydrogen atoms are deuterated, and which is provided with at least one substantially optically flat surface which admits or transmits rays of light having a large electric oscillation vector component in the direction of the axis of maximum absorption present in the ac face of a nuclear crystal. In formula (I) R represents a C1 or C2 alkyl or haloalkyl.