Quantum interference in electro-optic polymeric materials

The performance of polymer-based electro-optic modulator is very dependent on the wavelength of operation of the device. Surprisingly, most of our intuitive understanding of the molecular performance in such devised are based on studies performed in the off-resonance regime, where the nonlinear optical response of the molecule is by assumption not dependent on the wavelength of operation; or/and two-level model extrapolation, where the response is assumed to be dominated by the contribution of only one excited state. In either case, the effects of quantum interference (cancellation and enhancement of the response due to interactions between multiple excited states) are ignored. In this paper we show how in complex molecules with more than one excited state, quantum interference effects plays an important role in determining the on-resonant response, and hence should not be ignored when studying the response of organic-based electro-optic materials. We use this principle to interpret previous experimental results on the performance of electro-optic modulations under enhanced radiation environments.