Ultrafast 3D X-Ray Fluorescence Imaging

Coherent diffraction imaging with X-ray free-electron lasers (FELs) combines high spatial and temporal resolutions, but is limited to forward scattering and thus, 2D projections of the sample. Here, we study the potential of incoherent diffractive imaging (IDI) proposed by Classen et al. (2017) which is based on fluorescence emission from the specimen into the full solid angle.



Classen et al. (2017) suggested that intensity correlations calculated from X-ray fluorescence speckle patterns can be used for structure determination of the sample if the exciting FEL pulse duration is of the order of the corresponding transition lifetime. Inoue et al. (2019) and Nakamura et al. (2020) experimentally demonstrated how IDI can be utilized for FEL pulse duration measurements and FEL nanofocus characterization respectively.



In this contribution, we will present recent experimental IDI data recorded using sub-femtosecond FEL pulses available at SLAC/LCLS from thin metal samples. We reproduce the findings of Inoue et al. and Nakamura et al. for X-ray pulse duration measurements and nanofocus characterization. Furthermore, we present evidence confirming the 3D structure determination capabilities of IDI.