High-power laser beamlines typically operate with fixed focusing conditions,limiting the focal spot size and peak intensity.To mitigate these restrictions,prior studies used curved plasma mirrors to adjust the F-numbe...High-power laser beamlines typically operate with fixed focusing conditions,limiting the focal spot size and peak intensity.To mitigate these restrictions,prior studies used curved plasma mirrors to adjust the F-number to a specific value.Here,a double-plasma-mirror(DPM) system including spherical optics in a telescope configuration is implemented to adapt the F-number of a multi-petawatt(PW) laser beam resulting in adjustability within a range of intensities.The system is optimized to minimize focal aberrations.A dedicated imaging system is used to evaluate focus quality and the DPM reflectivity at the multi-PW level.Temporal contrast enhancement of the reflected beam is additionally demonstrated,as evidenced by higher particle yield and proton kinetic energy from nanometer-thick foils,compared to results without DPMs.These findings enable multi-PW laser facilities to explore more extreme laserplasma conditions that require ultra-high temporal contrast and intensity,while expanding their capabilities in intensity adjustment beyond designed specifications.展开更多
基金supported by the IOSIN Funds for Research Infrastructures of National Interest funded by the Romanian Ministry of Research,Innovation and Digitalizationthe support of the Czech Science Foundation through grant GACR24-11398S
文摘High-power laser beamlines typically operate with fixed focusing conditions,limiting the focal spot size and peak intensity.To mitigate these restrictions,prior studies used curved plasma mirrors to adjust the F-number to a specific value.Here,a double-plasma-mirror(DPM) system including spherical optics in a telescope configuration is implemented to adapt the F-number of a multi-petawatt(PW) laser beam resulting in adjustability within a range of intensities.The system is optimized to minimize focal aberrations.A dedicated imaging system is used to evaluate focus quality and the DPM reflectivity at the multi-PW level.Temporal contrast enhancement of the reflected beam is additionally demonstrated,as evidenced by higher particle yield and proton kinetic energy from nanometer-thick foils,compared to results without DPMs.These findings enable multi-PW laser facilities to explore more extreme laserplasma conditions that require ultra-high temporal contrast and intensity,while expanding their capabilities in intensity adjustment beyond designed specifications.
