NONLINEAR OPTICAL-RESPONSE TO STRONG APPLIED ELECTROMAGNETIC-FIELDS IN POLYCONJUGATED MATERIALS

Recent applications in the field of photonics require materials with a large, non-linear response to applied fields. Among the tools that can indicate which organic material has a large hyperpolarizability, there is vibrational spectroscopy. It is shown here that materials with very large Raman intensities have a large, second hyperpolarizability accounted for in terms of relaxation mechanism; it is also suggested that doped materials, which have an anomalously large infrared intensity, can have a large, first hyperpolarizability. Moreover, the relaxation mechanism involved in hyperpolarizabilities can be explained in terms of changes in geometries along the direction of the 'effective conjugation coordinate' R.