Consecutive attosecond pulses reveal the dynamics of excitons ensuing from core-electron excitation in silica. A quick glimpse of the x-ray aftermath X-rays pass through your skin to reveal the inner workings below. At the atomic scale, x-rays skip past valence electrons to grab hold of the core electrons closer to the nucleus. Moulet et al. used two successive, extremely short laser pulses (lasting less than a quadrillionth of a second) to initiate and then track this process in a sample of silica. This study uncovered the angular momentum character and relaxation dynamics of the excitons, or electron-hole pairs, ensuing from the x-ray absorption. Science, this issue p. 1134 The dynamic response of excitons in solids is central to modern condensed-phase physics, material sciences, and photonic technologies. However, study and control have hitherto been limited to photon energies lower than the fundamental band gap. Here we report application of attosecond soft x-ray and attosecond optical pulses to study the dynamics of core-excitons at the L2,3 edge of Si in silicon dioxide (SiO2). This attosecond x-ray absorption near-edge spectroscopy (AXANES) technique enables direct probing of the excitons’ quasiparticle character, tracking of their subfemtosecond relaxation, the measurement of excitonic polarizability, and observation of dark core-excitonic states. Direct measurement and control of core-excitons in solids lay the foundation of x-ray excitonics.

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软 X 射线激子

连续的阿秒脉冲揭示了二氧化硅中核电子激发引起的激子动力学。X 射线后遗症的快速一瞥 X 射线穿过您的皮肤，揭示下面的内部运作。在原子尺度上，X 射线跳过价电子以抓住更靠近原子核的核心电子。穆莱等人。使用两个连续的、极短的激光脉冲（持续时间不到千万亿分之一秒）来启动和跟踪二氧化硅样品中的这一过程。这项研究揭示了由 X 射线吸收引起的激子或电子-空穴对的角动量特性和弛豫动力学。科学，这个问题 p。1134 固体中激子的动态响应是现代凝聚相物理学、材料科学和光子技术的核心。然而，迄今为止，研究和控制仅限于低于基本带隙的光子能量。在这里，我们报告应用阿秒软 X 射线和阿秒光脉冲来研究二氧化硅 (SiO2) 中 Si 的 L2,3 边缘的核激子动力学。这种阿秒 X 射线吸收近边光谱 (AXANES) 技术能够直接探测激子的准粒子特性、跟踪它们的亚飞秒弛豫、测量激子极化率以及观察暗核激子态。固体中核激子的直接测量和控制奠定了 X 射线激子学的基础。3 二氧化硅（SiO2）中Si的边缘。这种阿秒 X 射线吸收近边光谱 (AXANES) 技术能够直接探测激子的准粒子特性、跟踪它们的亚飞秒弛豫、测量激子极化率以及观察暗核激子态。固体中核激子的直接测量和控制奠定了 X 射线激子学的基础。3 二氧化硅（SiO2）中Si的边缘。这种阿秒 X 射线吸收近边光谱 (AXANES) 技术能够直接探测激子的准粒子特性、跟踪它们的亚飞秒弛豫、测量激子极化率以及观察暗核激子态。固体中核激子的直接测量和控制奠定了 X 射线激子学的基础。