Nonlinear optical dye, photorefractive material composition, photorefractive substrate and hologram recording medium

Abstract

A nonlinear optical dye includes a compound represented by the general formula (1) below. In the above general formula (1), each of X1, X2, X3 and X4 independently represents a hydrogen atom, an alkyl group having a carbon number of 1 to 6, a halogen atom, a hydroxyl group, a nitro group, a cyano group, or a methylsulfonyl group. In the present invention, it is preferred that each of X1, X2, X3 and X4 independently represents a hydrogen atom, an alkyl group having a carbon number of 1 to 6, or a halogen atom. In the present invention, it is also preferred that the nonlinear optical dye has a dipole moment of 2.1 D or less and a maximum absorption wavelength within a range of 315 to 360 nm.

Dependencies are inferred from the claim text.