Two-beam coupling with chirp controlled pulses in media with two-photon resonances

Summary form only given. The use of two-beam coupling (TBC) techniques combined with ultrashort pulses have recently been used to probe the interaction between light and matter. With chirped pulses the arrival time of the different frequency components becomes an important parameter to determine the energy transfer between the pump and probe pulses. In such experiments it is important to be able to distinguish between the different nonlinearities that contribute for TBC. We present experimental results for TBC in coumarin and a mesoionic compound where two-photon absorption is present.