Intrinsic Hyperpolarizabilities as a Figure of Merit for Electro-optic   Molecules
  We propose the scale-invariant intrinsic hyperpolarizability as a measure of the figure of merit for electrooptic molecules. By applying our analysis to the best second-order nonlinear-optical molecules that are made using the present paradigms, we conclude that it should be possible to make dye-doped polymers with electrooptic coefficients of several thousand picometers per volt. 
Juefei Zhou, Mark G. Kuzyk