Self-phase modulation and compression of few-optical-cycle pulses

The nonlinear propagation of few-optical-cycle pulses through a dispersive Kerr medium, as, e.g., fused silica, is studied theoretically using a global approach to dispersion without applying the slowly varying envelope approximation. Contrary to amplitude self-steepening, a nearly triangular pulse shape with the steep side on the leading front is predicted. The calculation of the ultrawide spectrum and the spectral phases demonstrates that half-cycle pulses with a full width at half maximum as short as 0.5 fs and single-cycle pulses can be generated by the application of an appropriate broadband modulator for the compensation of the frequency-depending phase.