Published online by Cambridge University Press: 25 February 2011
The promise of conjugated polymers as fast response nonlinear optical materials has been emphasized, since the nonresonant third order nonlinear susceptibilities of these π-electron polymers are among the largest measured in any material. For example, third harmonic generation (THG) experiments have shown that for trans-polyacetylene, χ║(3)(3ω:ωω,ω) = (4± 2) × 10-10 esu, where χ║(3) refers to that component of the third order susceptibility tensor with all indices parallel to the chain direction [1]. The large nonlinear response is anisotropic and arises from the π-electrons of the conjugated polymer. The magnitude and anisotropy are comparable to results obtained from single crystals of polydiacetylene-(toluenesulfonate). Given these large χ║(3) values, it is important to develop methods for fabricating chain-aligned (oriented) conjugated polymer films which have optical quality.