Key trade-offs for second harmonic generation in poled polymers

We discuss the critical trade-off between the spectral dispersion in the second order nonlinearity d(2) and the linear absorption coefficient for second harmonic generation (SHG) by the mixing of copropagating or counterpropagating fundamental beams in poled polymers. The 4-dimethylamino–4′-nitrostilbene side-chain polymer is used as a specific example. The predictive power of the classical two-level model for SHG is also assessed.