Broadband ptychography using curved wavefront illumination

We examine the interplay between spectral bandwidth and illumination curvature in ptychography. By tailoring the divergence of the illumination, broader spectral bandwidths can be tolerated without requiring algorithmic modifications to the forward model. In particular, a strong wavefront curvature transitions a far-field diffraction geometry to an effectively near-field one, which is less affected by temporal coherence effects. The relaxed temporal coherence requirements allow for leveraging wider spectral bandwidths and larger illumination spots. Our findings open up new avenues towards utilizing pink and broadband beams for increased flux and throughput at both synchrotron facilities and lab-scale beamlines.

Automated summary

We explore how spectral bandwidth and illumination curvature interact in ptychography. By adjusting the divergence of the illumination, broader spectral bandwidths can be accommodated without needing to modify the algorithmic forward model. A strong wavefront curvature changes the diffraction geometry from far-field to effectively near-field, reducing the impact of temporal coherence effects. The relaxed temporal coherence requirements enable the use of wider spectral bandwidths and larger illumination spots. Our findings pave the way for utilizing pink and broadband beams to enhance flux and throughput in synchrotron facilities and laboratory-scale beamlines.