Controlling the noncentrosymmetry of azodye-doped polymers by nonresonant dual-frequency coherent excitation.

All-optical control of the noncentrosymmetry of azodye-doped polymer films was demonstrated by nonresonant dual-frequency coherent excitation. The tensor analysis of the photoinduced noncentrosymmetry was performed by monitoring second harmonic generation (SHG) of the samples. The quadratic dependence of SHG on the film thickness showed that a χ[sup (2)] grating satisfying the phase-matching condition for SHG was optically induced in the polymer films, indicating this nonresonant all-optical poling can be used to tailor the symmetry of bulk samples. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]