Analysis of quadratic chirp effects on femtosecond pulse propagation in fused silica

The effects of linear chirp (LC), quadratic chirp (QC), and the combined linear and quadratic chirps (L-QC) on the spatio-temporal and spectral properties of femtosecond pulses propagation taking into account the diffraction, group-velocity dispersion and self-focusing effects are studied. We conduct a detailed analysis of the distinct roles played by LC and QC components in L-QC pulse. The results indicate that, compared with LC pulse, the incorporation of QC in L-QC pulse aids in achieving further compression of both the pulse duration and beam width, while also enabling the adjustment of the latency time of peak intensity. On the other hand, compared with QC pulse, the inclusion of the LC component in the L-QC pulse facilitates easier adjustment of the spectral width, enabling it to be broadened or narrowed. The results demonstrate that the L-QC pulse exhibits greater adjust- ability, allowing for modulation of the intensity and spectral distributions of the pulse by adjusting respective contributions and parameters of the LC and QC.