Spectral phase effects and control requirements of coherent beam combining for ultrashort ultrahigh intensity laser systems.

Based on the premise that further improvements to the size and damage threshold of large-aperture optical components are severely limited, coherent beam combining (CBC) is a promising way to scale up the available peak power of pulses for ultrashort ultrahigh intensity laser systems. Spectral phase effects are important issues and have a significant impact on the performance of CBC. In this work, we analyze systematically factors such as spectral dispersions and longitudinal chromatism, and get the general spectral phase control requirements of CBC for ultrashort ultrahigh intensity laser systems. It is demonstrated that different orders of dispersion influence intensity shape of the combined beam, and high-order dispersions affect the temporal contrast of the combined beam, while the number of the channels to be combined has little impact on the temporal Strehl ratio (SR) of the combined beam. In addition, longitudinal chromatism should be controlled effectively since it has a detrimental effect on the combined beam at the focal plane, both temporally and spatially.