Charge-injection-induced optical nonlinearity in in-plane poled polymer films: enhanced temporal stability and effect of different polymeric matrices and substrates

Significant asymmetry and optical nonlinearity (second harmonic generation) can be produced by injection of electric charge into dye/polymer blends. The strength of the nonlinearity and its temporal stability depend on the electrical properties of the polymer and the polymer interface. It is shown conclusively that the mechanism for producing the nonlinearity does not arise from dipolar alignment of the dye in an electrostatic field; we even demonstrate production of nonlinearity under conditions of alternating current injection i.e. zero electrostatic field.