Multiplexing limits in ptychography

Ptychography is a lensless modality for high-resolution imaging, in which the lateral extension of the sample is only limited by the area scanned. Multiplexing capabilities are known and used to scan larger areas faster by using multiple beams simultaneously. In this work, the limits of massive multiplexing to enhance imaging throughput are systematically investigated. Through an experimental study, a more than sixfold increase in throughput is demonstrated by spatially separating and scanning independent regions with 16 beams. This is the highest number of multiplexed beams to date, and the highest throughput increase reported so far. Furthermore, in a numerical investigation, multiplexed ptychography measurements with 64 beams are demonstrated, only limited by the numerical constraints imposed by the reconstruction algorithm. It is observed that the requirements for successfully reconstructing additional areas depend on both a high degree of beam overlap (i.e., more scan positions per area) and the information oversampling ratio. Exploring the limits of multiplexing paves the way for high-throughput ptychography using incoherent light sources, such as laser-produced plasmas. Furthermore, these findings are expected to be applicable to other multiplexing scenarios, including polarisation, temporal, and spectral multiplexing, such as ptychography experiments with high harmonic generation (HHG) sources, where photon flux is limited, and additional flux can be gained from multiplexing neighboring spectral lines.