We report experimental results regarding laser-plasma instabilities (LPI) developed by monochromatic and broadband green lasers with moderate bandwidths (0.2% and 0.6%) at intensities of 5–7 W cm−2 in the interest of inertial fusion energy. Angular-resolved distributions of scattered light were diagnosed, which demonstrated that the laser absorption rate is enhanced by increasing the laser bandwidth. This enhancement is primarily owing to the mitigation of stimulated Brillouin scattering. Meanwhile, the inherent temporal fluctuation of laser intensity caused by bandwidth results in more intense stimulated Raman scattering, particularly regarding the sidescattering. These findings indicate that the requirement of laser bandwidth used in inertial fusion energy should exceed the moderate level to achieve comprehensive mitigation of LPI.
This paper investigates the impact of laser bandwidth on laser-plasma instabilities in the context of inertial fusion energy. It shows that increasing the laser bandwidth can enhance the laser absorption rate by mitigating stimulated Brillouin scattering, but also leads to more intense stimulated Raman sidescattering due to temporal fluctuations in laser intensity.