Optical Third-Harmonic Generation from Highly Oriented Polydiacetylene Thin Films Deposited by Vacuum Deposition

Third-harmonic generation measurements are made on highly oriented polydiacetylene thin films fabricated by vacuum deposition. The thin films are obtained by controlling vacuum deposition conditions. The anisotropy of third order optical nonlinear susceptibility for the films was evaluated by measuring the intensity of third-harmonic generation. The susceptibilities along and across the π-conjugated polymer chain are evaluated to be χ(3)=1.1×10-11 esu and χ(3)<10-12 esu at 1.9 µm wavelength, respectively.