Suppression of nonlinear imaging in high-power laser by pulse bandwidth

The formation of hot image in a broadband laser system is numerically studied. It is found that in a broadband system the hot image is, though the same in location, well restrained by the bandwidth and has a peak intensity much smaller when compared to that in a narrowband system. In addition, the quantitative description for the influences of bandwidth on the hot image and on the uniformity of the beam is presented by modifying the chirp and temporal width of pulse. The results show that the intensity of the hot image and the corresponding contrast are inversely proportional to the chirp and proportional to the temporal width of the incident pulse, indicating that a bandwidth can suppress the formation of a hot image and improve the uniformity. The physical reasons for such a suppressing