X-ray free electron lasers (XFELs) now routinely produce millijoule level pulses of x-ray photons with tens of femtoseconds duration. Such x-ray intensities gave rise to the idea that weakly scattering particles—perhaps single biomolecules or viruses—could be investigated free of radiation damage. Here, we examine elements from the past decade of so-called single particle imaging with hard XFELs. We look at the progress made to date and identify some future possible directions for the field. In particular, we summarize the presently achieved resolutions as well as identifying the bottlenecks and enabling technologies to future resolution improvement, which in turn enables application to samples of scientific interest.

中文翻译：

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高重复率x射线自由电子激光源问世时，用x射线对单粒子成像的观点。

现在，X射线自由电子激光器（XFEL）通常会产生数十飞秒持续时间的毫焦耳级X射线光子脉冲。这种X射线强度引起了这样的想法，即可以对弱散射粒子（可能是单个生物分子或病毒）进行研究，而不会受到辐射的损害。在这里，我们研究了过去十年中使用硬XFEL进行的所谓单粒子成像的元素。我们着眼于迄今取得的进展，并确定了该领域未来可能的发展方向。特别是，我们总结了目前已实现的解决方案，并确定了瓶颈并为将来的解决方案改进提供了技术支持，从而又使这些解决方案可应用于具有科学意义的样本。