Speaker
Description
Ultrafast and intense X-ray free electron laser (XFEL) pulses can visualize non-equilibrium dynamics on the femtosecond time scale with high spatial resolution at single nanoparticle (NP) level . Single exposure coherent diffraction imaging (CDI) of individual nanospecimen has been so far limited to a few nanometers. The limiting factor is sample bleaching through photo-ionization and resulting low photon signal in higher scattering angles.
Our preliminary data analysis from experiments at LCLS and the EuXFEL indicates, that transient resonances might overcome bleaching in images recorded with intense, hard X-rays pulses and increase the spatial resolution. We have recorded small and wide-angle scattering (Bragg CDI) from Au NPs with sizes ranging from 4-70 nm. We observe multiple Bragg peaks from a single domain 10 nm NP, which exhibit multiple higher diffraction orders. The small angle X-ray diffraction signal reaches up to 1 nm resolution in images of samples, where the best previously reported reconstruction achieves only 2 nm resolution. Our data also suggests that 10 fs FEL pulses might be too long to observe true atomic resolution in single metal particle imaging.
By combining small angle CDI and wide angle BCDI, we obtain complementary structural information, with both techniques capturing multiple diffraction orders. This proof-of-concept study highlights a pathway for improving single-shot resolution and offers new insights into ultrafast structural dynamics at the nanoscale.
| Scientific Topics | Imaging |
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