| 摘要 |
PROBLEM TO BE SOLVED: To provide nonlinear optical pigments having little absorption in the visible light region, and thereby provide a multicolor photorefractive substrate with high permeability, excellent diffraction response speed and excellent diffraction efficiency.SOLUTION: The nonlinear optical pigments are made of compounds represented by the specified general formula I, where X1 and X2 are each independently a halogen; X is a halogen or a cyano compound; and R is hydrogen, or a Calkyl group or Calkenyl group that may be substituted with an electron-donating group.] |
