Hot images from phase defects in high-power broadband laser beams

We investigate the formation of hot image from the phase defect in broadband laser beam. It is found that the hot image intensity in the broadband beam case is lower than that in the narrowband beam case under the same input peak intensity, indicating that the formation of hot image can be suppressed by a small amount of bandwidth. The physical origins for such a suppression effect are explained. In addition, an interesting phenomenon found is that the phase defects causing phase shifts around π rad become less dangerous than those around ±π/2 rad when the peak power of the incident broadband laser beam reaches a certain level. Numerical simulations are performed to confirm the theoretical analyses.