Generation of bright phase-matched circularly-polarized extreme ultraviolet high harmonics
Generation of bright phase-matched circularly-polarized extreme ultraviolet high harmonics
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DOI：
10.1038/nphoton.2014.293
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发表时间：
2015-02-01
期刊：
影响因子：
35
通讯作者：
Cohen, Oren
中科院分区：
文献类型：
--
作者：
Kfir, Ofer;Grychtol, Patrik;Cohen, Oren
圆偏振极紫外和 X 射线辐射可用于分析材料的结构、电子和磁性特性。迄今为止，这种辐射仅在同步加速器等大型 X 射线设施中可用。在这里，我们展示了第一个明亮的、相位匹配的、极紫外圆偏振高谐波源。当双色反向旋转圆偏振激光脉冲场电离空心波导中的气体时，会发出谐波。我们使用这种新光源在 Co 的 M 壳吸收边进行磁圆二色性测量。我们表明，圆偏振谐波的相位匹配是独特且稳健的，产生的光子通量可与线偏振高谐波源相媲美。这项工作代表了开发桌面系统的关键进展，该系统可在磁性和其他手性介质中同时进行元素特异性成像和多个元素的光谱分析，具有非常高的空间和时间分辨率。
Circularly-polarized extreme ultraviolet and X-ray radiation is useful for analysing the structural, electronic and magnetic properties of materials. To date, such radiation has only been available at large-scale X-ray facilities such as synchrotrons. Here, we demonstrate the first bright, phase-matched, extreme ultraviolet circularly-polarized high harmonics source. The harmonics are emitted when bi-chromatic counter-rotating circularly-polarized laser pulses field-ionize a gas in a hollow-core waveguide. We use this new light source for magnetic circular dichroism measurements at the M-shell absorption edges of Co. We show that phase-matching of circularly-polarized harmonics is unique and robust, producing a photon flux comparable to linearly polarized high harmonic sources. This work represents a critical advance towards the development of table-top systems for element-specific imaging and spectroscopy of multiple elements simultaneously in magnetic and other chiral media with very high spatial and temporal resolution.