Potential continuous zooming scheme based on high-power broadband laser

Continuous zooming is efficient in mitigating the cross-beam energy transfer effect and improving implosion hydrodynamic efficiency in the application of inertial confinement fusion. In this paper, a novel continuous zooming scheme is proposed, based on the chromatic aberration effect of the lens groups to gradually reduce the size of the focal spot at the target position by focusing the broadband laser pulse. This scheme is simulated theoretically on the Shenguang-II upgrade (SG-II UP) facility, and the results show that the focal spot size is positive and linear for the beam wavelength. When the fundamental wave bandwidth was 5 nm, the focal spot radius was reduced by 15.21% without changing the geometric parameters of the SG-II upgrade, and the focal spot radius was reduced by 27.73% after optimization. In addition, the conversion efficiency is compensated for in the harmonic converter. This paper supports a new perspective for the realization of high-power laser zooming.