Synthesis, Structural and Nonlinear Optical Properties of 2-(3-Cyano-4-{5-[1-(2-Hydroxyethyl)- 3,3-Dimethyl-1,3-Dihydro-Indol-2-ylidene]-Penta-1,3-dienyl}-5,5-Dimethyl-5H-Furan-2-ylidene)-Malononitrile

Abstract

A chromophore for nonlinear optics with extended conjugation has been synthesized, and its structure determined from X-ray diffraction data. The compound crystallizes in the monoclinic system with the space group P2₁/n and Z = 4. The unit cell parameters are a = 10.7826(4) Å, b = 14.5943(5) Å, c = 15.3792(5) Å and beta = 96.213(2)°. A thin film containing 5% of the chromophore in amorphous polycarbonate when poled at 180°C and 60 V/μm yields a maximum r₃₃ value of 206 pm/V. This is seven times higher than the value found for the archetypical inorganic material, lithium niobate.

Keywords:

• Electro-optic coefficient
• nonlinear optical chromophore
• X-ray crystallography

Acknowledgment

This research was funded by the New Zealand Foundation for Research, Science and Technology (contract no. C08X0704).