Ultra-broadband hyperspectral diffraction imaging using a ptychographic probe

Coherent diffractive imaging (CDI) is a powerful tool for X-ray nanoscopy. However, CDI's stringent coherence requirement has severely hindered its application under broadband illumination, which is increasingly desirable due to recent advances in attosecond science and laboratory-scale X-ray sources. Here we report a hyperspectral diffraction imaging (HDI) technique under ultra-broadband illumination. An approach termed ptychographic probe is designed to introduce spatial-spectral constraints for coherent modes decomposition. The feasibility of HDI is validated through simulation and experiments, demonstrating high performance. Under broadband illumination with a 60% bandwidth, holographic reconstructions across 34 spectral channels are achieved. Our HDI method establishes a comprehensive spectrophotography solution for broadband CDI, offering universal applicability to dispersive objects - those that exhibit varying spectral responses across different regions. It will significantly advance the implementation of CDI with table-top X-ray sources and attosecond lasers in areas such as ultrafast nanoscopy, materials science and biomedicine.