2ND-ORDER NONLINEARITY OF A NOVEL DIAZO-DYE-ATTACHED POLYMER

Second-order nonlinear optical properties of a newly synthesized dye-attached polymer (3R) were investigated. The dye has a conjugated diazo structure, and the beta-mu-g (beta: second-order molecular hyperpolarizability, mu-g: dipole moment in the ground state) is larger than five times that of a monoazo dye (2R). The second-order nonlinear coefficient (chi(2)) of a 3R polymer is also greater than that of a 2R polymer throughout the fundamental wavelength of 1.06 mu-m and between from 1.50 to 1.70 mu-m when the polymers are electrically poled. For both polymers, the chi(2) dependence on the fundamental wavelength corresponds to the absorption spectrum, which is explained by two-photon resonance near the absorption maxima. The attainable chi(2) of the polymers deviates from the theoretical linear relationship with the dye content when it is high. This indicates that the dipolar interaction increases as the dye content rises.