Deformation of the Focal Spot of an Ultrashort High-Power LaserPulse due to Chromatic Aberration by a Beam Expander

摘要

The spatial and temporal intensity distribution of a focal spot is investigated when an ultrashorthigh-power laser pulse is focused with chromatic aberration induced by a simple beam expander.The chromatic aberration due to the simple beam expander is calculated and measured for the100-TW Ti:sapphire laser system at the Advanced Photonics Research Institute. The chromaticaberration reduces the peak intensity of the focal spot and broadens the temporal profile of thefocal spot. By calculating the spatial and temporal intensity distribution of the focal spot, we canaccurately estimate the peak intensity of the focal spot for the ultrashort high-power laser pulse withchromatic aberration. To avoid chromatic aberration, an air-spaced achromatic beam expander isdesigned and characterized for application to the ultrashort high-power laser system.