Laser-plasma interaction (LPI) is a critical issue in laser-driven inertial confinement fusion (ICF) ignition, as it can significantly affect target compression and fusion energy gain. Broadband laser technology has emerged as a promising approach to mitigate LPI-related processes by effectively reducing the intensity of light experienced by the plasma, thereby potentially suppressing the onset and development of LPI instabilities. Compared to traditional narrowband lasers, broadband lasers exhibit a significant suppression effect on backscattered LPI processes, such as stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS), particularly at laser intensities below 1 × 10^¹⁵ W/cm². However, the absorption and transmission characteristics of broadband lasers are also critical for their practical application. In this study, we investigate the interaction of broadband and narrowband lasers with thin-film targets. Our experiments reveal that nanosecond-scale long-pulse laser irradiation can rapidly ablate thin-film targets, allowing subsequent laser energy to transmit through. By comparing the transmission energy results of broadband second-harmonic, narrowband second-harmonic, and narrowband third-harmonic lasers, we demonstrate the unique advantages of broadband lasers in terms of energy coupling and LPI suppression. These findings provide valuable insights into the absorption and transmission dynamics of broadband lasers, advancing our understanding of their potential applications in ICF and high-energy-density physics.

inertial confinement fusion (ICF) ignition,Laser-plasma interaction