ABSTRACT

The term “four-wave mixing” relates to nonlinear optical processes in which three optical fields interact to create a fourth optical field, usually each of the fields belonging to a different light beam. If all the beams have the same frequency, the process is called degenerate four-wave mixing (DFWM). For thin films of conju­ gated polymers and very short laser pulses, the usual geometry of the experiment is the so-called BOXCARS geometry or forward-scattering geometry [4], Figures 9 and 10 show a scheme of an experiment in which such a geometry is used.