Synthesis and evaluation of cumulenes: novel rigid nonlinear optical molecules

Abstract

We report our investigations of the cumulenes, a novel class of compounds proposed for use as the active second- and thirdorder nonlinear optical component materials for electro-optic and all-optical devices. Unlike conjugated organic nonlinear optical molecules based on alternating multiple and single bonds, these molecules contain a contiguous, or "cumulated" system of double bonds, leading to a highly rigid one-dimensional backbone of polarizable ic-electrons. A series of symmetrically- and asymmetrically-substituted teiraphenyl cumulenes has been synthesized and characterized. D.C. electric field-induced second harmonic generation experiments show significant second-order nonlinear susceptibilities in a series of polar cumulenes. Preliminary results showing evidence of resonant and nonresonant third-order nonlinear optical activity are also reported.