千电子伏光子能量下可能量扩展的单脉冲阿秒发射
Energy-scalable single-burst attosecond emission at kiloelectronvolt photon energies
查看机构详情
- RIKEN Center for Advanced Photonics, RIKEN（理化学研究所先进光子学研究中心）
机构由 AI 辅助整理，请以论文原文为准。
浏览论文内容
中文总结 AI 辅助
利用CEP稳定的中红外激光系统与米级弱聚焦低压相位匹配，生成达1.2千电子伏的相干软X射线连续谱，实现过渡金属L边区域的孤立阿秒脉冲产生，并展示多元素宽带吸收光谱能力。
中文摘要 AI 辅助
千电子伏光子能量下的阿秒软X射线脉冲将能够直接探测过渡金属的L边，从而在电荷、自旋和轨道动力学的固有时间尺度上实现元素特异性研究。然而，由于迄今为止唯一被证明的相位匹配千电子伏高次谐波源采用了无载波包络相位（CEP）控制的多周期驱动脉冲，该光谱区域内的阿秒发射一直难以实现。因此，千电子伏光子能量与CEP控制的阿秒发射之间长期存在差距。在此，我们利用CEP稳定的中红外激光系统，其脉冲宽度可调至亚周期范围，弥合了这一差距。通过在米级弱聚焦条件下低压中性氦中的相位匹配高次谐波产生，我们生成了达到1.2千电子伏的相干软X射线连续谱。关键的是，我们观察到CEP依赖的光谱调制延伸至过渡金属L边区域，提供了与孤立阿秒脉冲产生一致的实验证据。为展示我们光源的能力，我们进行了覆盖Ti、Fe、Co和Ni L边以及O K边的宽带软X射线吸收光谱测量，并解析了近边精细结构。通过将米级弱聚焦与低压相位匹配相结合，我们的方法解决了以往千电子伏高次谐波源的关键能量扩展限制，并建立了一个相位匹配、CEP控制的千电子伏软X射线平台，用于磁性、量子及强关联材料的阿秒光谱学。
英文摘要
Attosecond soft-X-ray pulses at kiloelectronvolt photon energies would provide direct access to the L-edges of transition metals, enabling element-specific studies of charge, spin, and orbital dynamics on their intrinsic timescales. However, attosecond emission in this spectral region has remained elusive because the only phase-matched keV high-harmonic source demonstrated to date employed multicycle driving pulses without carrier-envelope-phase (CEP) control. A long-standing gap has therefore persisted between keV photon energies and CEP-controlled attosecond emission. Here, we bridge this gap using a CEP-stabilized mid-infrared laser system with pulse durations tunable to the sub-cycle regime. Through phase-matched highharmonic generation in low-pressure neutral helium under meter-scale loose-focusing conditions, we generate coherent soft-X-ray continua reaching 1.2 keV. Crucially, we observe CEP-dependent spectral modulation that reaches into the transition-metal L-edge region, providing experimental evidence consistent with the generation of isolated attosecond pulses. To demonstrate the capabilities of our source, we perform broadband soft-X-ray absorption spectroscopy spanning the Ti, Fe, Co, and Ni L-edges, as well as the O K-edge, and resolve near-edge fine structures. By combining meter-scale loose focusing with low-pressure phase matching, our approach addresses key energy-scaling limitations of previous keV high-harmonic sources and establishes a phase-matched, CEP-controlled keV soft-X-ray platform for attosecond spectroscopy of magnetic, quantum, and strongly correlated materials.
