Both Spatial and Temporal Distortions Caused by Spatial Chirp in Vortex Femtosecond Pulse Beams

Abstract

Spatial chirp will cause temporal width broadening and wave front aberration with the femtosecond pulse beam. So effectively controlling and utilizing the spatial chirp has great significance. In this manuscript, the properties of the spatial chirp are theoretically investigated. An experimental setup which can easily control the spatial chirp of the femtosecond laser pulse beam and generate vortex femtosecond pulse beam with different spatial chirp parameters is proposed. The relationships between the spatial chirp and the temporal and spatial properties including the cross section intensity distributions and the temporal width and chirp of the femtosecond pulse beams are obtained. Both theoretical and experimental results indicate that as the spatial chirp parameter becomes larger, both the temporal and spatial pulse beam widths are broadening and the wave front aberration also becomes larger quickly. Moreover, the temporal chirp is also becoming larger when the spatial chirp parameter becomes larger. The spatial chirp properties of vortex and Gaussian femtosecond pulse beams are similar with each other.