Dynamic chromatic aberration pre-compensation scheme for ultrashort petawatt laser systems

A novel chromatic aberration pre-compensation scheme for ultrashort petawatt laser systems was proposed. The pre-compensation scheme consists of a convex lens, group of concave lenses, and a spherical reflector combined with a conventional vacuum chamber. It provides a versatile method to accurately compensate the chromatic aberration of an entire laser system via controlling the amount of propagation time delay (PTD) induced by the compensator without changing the input and output beam size. A compensator, tailored based on the proposed scheme, was designed and experimentally evaluated for the Shen-Guang-II 5PW (SG-II 5PW) laser system at Shanghai Institute of Optics and Fine Mechanics (SIOM). The experimental results verified that chromatic aberration in the laser system was almost fully compensated: the size of laser beam focused by an f/2.42 off-axis parabolic mirror (OAP) was reduced tremendously from 32×18μm2to about 4×4μm2at full width at half maximum (FWHM). The proposed scheme provides the flexibility to accurately correct chromatic aberration in high-power laser systems within a wide dynamic range.