We put forward a co-axial pump (optical)-probe (x-rays) experimental concept and show performance of the optical component. A Bessel beam generator with a central 100 m diameter hole (on the optical axis) was fabricated using femtosecond (fs) laser structuring inside a silica plate. This flat-axicon optical element produces a needle-like axial intensity distribution which can be used for the optical pump pulse. The fs-x-ray free electron laser (X-FEL) beam of sub-1 m diameter can be introduced through the central hole along the optical axis onto a target as a probe. Different realisations of optical pump are discussed. Such optical elements facilitate alignment of ultra-short fs-pulses in space and time and can be used in light–matter interaction experiments at extreme energy densities on the surface and in the volume of targets. Full advantage of ultra-short 10 fs-X-FEL probe pulses with fs-pump (optical) opens an unexplored temporal dimension of phase transitions and the fastest laser-induced rates of material heating and quenching. A wider field of applications of fs-laser-enabled structuring of materials and design of specific optical elements for astrophotonics is presented.

我们提出了同轴泵浦（光学）探针（x射线）的实验概念，并展示了光学组件的性能。具有中央100的贝塞尔光束发生器使用飞秒（fs）激光在二氧化硅板内部进行结构加工，制得一个直径为m的孔（在光轴上）。该扁平轴锥光学元件产生可用于光泵浦脉冲的针状轴向强度分布。sub-1的fs-x射线自由电子激光（X-FEL）光束可以通过光轴的中心孔将直径为m的直径引入到作为探针的目标上。讨论了光泵的不同实现。这样的光学元件有助于在空间和时间上对准超短fs脉冲，并可以在目标和物体表面上具有极高能量密度的光-物质相互作用实验中使用。具有fs-pump（光学）的超短10 fs-X-FEL探测脉冲的全部优势为相变提供了一个未知的时间维度，并以最快的激光诱导速率加热和淬灭了材料。提出了具有fs激光功能的材料结构和用于航天光子学的特定光学元件设计的更广阔的应用领域。