Characterizing the nonlinear propagation of femtosecond pulses in bulk media

Frequency-resolved optical gating is used to characterize the amplitude and phase of intense femtosecond pulses propagating in nonlinear dispersive media. The combined effects of group velocity dispersion (GVD) and third-order nonlinearity (nz) lead to rapid broadening and splitting of the pulses. We present measurements at 800 and 1200 nm and investigate the influence of the chirp of the input field. Measurements are compared with the predictions of one- and three-dimensional nonlinear Schrodinger equations. The influence of the Raman contribution to the nonlinear index of refraction is also examined theoretically.