We theoretically investigate the fluorescence intensity correlation (FIC) of Ar clusters and Mo-doped iron oxide nanoparticles subjected to intense, femtosecond, and sub-femtosecond x-ray free-electron laser pulses for high-resolution and elemental contrast imaging. We present the FIC of $K\alpha$ and $K{\alpha }^h$ emission in Ar clusters and discuss the impact of sample damage on retrieving high-resolution structural information and compare the obtained structural information with those from the coherent diffractive imaging (CDI) approach. We found that, while sub-femtosecond pulses will substantially benefit the CDI approach, few-femtosecond pulses may be sufficient for achieving high-resolution information with the FIC. Furthermore, we show that the fluorescence intensity correlation computed from the fluorescence of the Mo atoms in Mo-doped iron oxide nanoparticles can be used to image dopant distributions in the nonresonant regime.

中文翻译：

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使用强 X 射线脉冲具有高空间分辨率和元素对比度的荧光强度相关成像

我们从理论上研究了 Ar 簇和 Mo 掺杂的氧化铁纳米粒子在强、飞秒和亚飞秒 X 射线自由电子激光脉冲下的荧光强度相关性 (FIC)，用于高分辨率和元素对比度成像。我们提出了 FIC$钾\alpha$ 和 $钾{\alpha }^H$Ar 簇中的发射，并讨论样品损坏对检索高分辨率结构信息的影响，并将获得的结构信息与相干衍射成像 (CDI) 方法的结构信息进行比较。我们发现，虽然亚飞秒脉冲将大大有益于 CDI 方法，但几飞秒脉冲可能足以通过 FIC 获得高分辨率信息。此外，我们表明，根据 Mo 掺杂氧化铁纳米粒子中 Mo 原子的荧光计算的荧光强度相关性可用于对非共振区域中的掺杂剂分布进行成像。