Taking advantage of complementary measurements of the characteristics of both protons and electrons accelerated by a laser in a vacuum, we propose an advanced diagnostics of the parameters of the tightly focused high-intensity femtosecond laser pulse. The laser field description is based on Stratton–Chu integrals, which allow simulating laser pulses with different spatial–temporal profiles focused by an off-axis parabolic mirror down to the diffraction limit. The free particles, whose dynamics are calculated by the test particle method, are accelerated from a rarefied gas (almost a vacuum). We analyze the dependence of the particle spectra on the laser parameters: the laser peak intensity, focal spot size, and pulse duration. The results show that diagnostics obtained by simultaneously using protons and electrons allow increasing the estimation accuracy of measuring the focal spot size and the peak intensity and thus allow evaluating the laser pulse duration in the femtosecond range. Our proposal is a response to the urgent need to measure pulse durations in the focal spot for new PW-level class lasers of super-short duration up to ∼10 to 20 fs, which clearly demonstrate a current trend in laser technology.

利用在真空中由激光器加速的质子和电子特性的互补测量，我们提出了对紧密聚焦的高强度飞秒激光脉冲的参数进行高级诊断的方法。激光场的描述基于Stratton-Chu积分，可以模拟离轴抛物面反射镜聚焦到衍射极限的具有不同时空轮廓的激光脉冲。游离粒子的动力是通过测试粒子方法计算得出的，它是从稀有气体（几乎是真空）中加速生成的。我们分析了粒子光谱对激光参数的依赖性：激光峰值强度，焦点尺寸和脉冲持续时间。结果表明，通过同时使用质子和电子获得的诊断结果可以提高测量焦点尺寸和峰值强度的估计准确性，从而可以评估飞秒范围内的激光脉冲持续时间。我们的建议是对迫切需要在焦点处测量脉冲持续时间的一种新的PW级类激光器（持续时间约10至20 fs）的超短脉冲，这清楚地表明了激光技术的当前趋势。