Femtosecond measurement of cascaded second-order nonlinearities by spectrally resolved two-beam coupling

Summary form only given. The cascading of second-order processes under phase-mismatched conditions can lead to a Kerr-like nonlinearity. Large nonlinear phase shifts of either sign can be produced by the cascade process. It is known that this phase shift can be severely distorted owing to group velocity mismatch (GVM) between the fundamental pulse and its harmonic. Measurement of the temporal behavior of the cascade nonlinear phase on the femtosecond time scale is essential to its application in femtosecond devices. We show that the magnitude and dynamics of the cascade nonlinearities can be determined using spectrally resolved two-beam coupling (SRTBC) with femtosecond pulses.