Third-order nonlinear optical properties of processable polyazine thin films

The third-order nonlinear optical susceptibility χ(3)(−3ω;ω,ω,ω) of propylmethylpolyazine thin films as measured by the third harmonic generation is reported. The χ(3)(−3ω;ω,ω,ω) values of propylmethylpolyazine that possess statistically alternating methyl and propyl substituents on the carbon atoms along the conjugated chain were found to be 8.0×10−12 esu off resonance at 1.5 μm fundamental radiation. The interesting third-order nonlinear properties presumably originate from the unique periodicity of the main π-electron-conjugated polyazine backbone.