AI 中文总结
研究拍瓦级激光系统中残余角啁啾对质子加速的影响，通过原位光谱阻挡诊断消除其不利影响，恢复近衍射极限聚焦，使质子截止能量提高两倍，成功演示诊断和消除残余角啁啾，为高能质子束应用提供参考。
AI 中文摘要
激光驱动质子加速因在包括癌症治疗在内的多种应用中具有诱人潜力而备受关注。质子能量关键取决于靶上强度，但时空耦合引起的焦斑退化对加速的不利影响仍未得到充分阐明。本研究表明，拍瓦级激光系统中光栅压缩器的微小失准产生的残余角啁啾是质子加速的关键瓶颈。实验结果显示，即使约100微弧度的光栅失准也会导致焦斑大幅伸长和峰值强度显著降低。通过实施原位光谱阻挡诊断，有效消除了残余角啁啾并恢复了近衍射极限聚焦。这一优化使靶上强度显著恢复，质子截止能量提高了两倍。我们的工作成功演示了诊断和消除残余角啁啾，为在拍瓦级激光中产生高能质子束及其多种应用提供了实用参考。
英文摘要
Laser-driven proton acceleration has attracted considerable interest owing to its appealing potential in versatile applications including cancer therapy. Proton energies depend critically on the on-target intensities, yet the detrimental impact of focal spot degradation induced by spatiotemporal couplings on the acceleration remains insufficiently elucidated. In this study, we demonstrate that residual angular chirp (AC), stemming from minor misalignments of the grating compressor in a Petawatt-class laser system, acts as a critical bottleneck for proton acceleration. Experimental results reveal that even around 100 microradians of grating misalignment induces substantial focal-spot elongation and a pronounced reduction in peak intensity. By implementing an in situ spectral-blocking diagnostic, we effectively eliminated the residual AC and restored a near-diffraction-limited focus. This optimization led to a significant recovery of the on-target intensity, resulting in a twofold increase in the proton cutoff energy. Our work presents a successful demonstration of diagnosing and eliminating residual AC. This provides a practical reference for generating high-energy proton beams and supporting their diverse applications in a PW-class laser.
CommentsAccepted by Matter and Radiation at Extremes (MRE)
