Hysteresis of the spectral components of a femtosecond pulse propagating in a nonlinear medium

Numerical simulation based on the one-dimensional nonlinear Maxwell equations is used to study the frequency that provides the maximum spectral intensity in a selected time interval versus the amplitude of an incident femtosecond pulse. The hysteretic variation of this frequency with amplitude is shown to be a possibility. Analysis is performed in the approximation of an optically thick layer for a medium with a saturating restoring force.