Physics-informed vector ptychography for imaging vector order parameters

Resonant soft X-ray ptychography is capable of imaging magnetic materials down to a few nanometres resolution, but conventional reconstructions treat the specimen as a scalar transmission function, discarding the vector information carried by resonant scattering. Optical vector ptychography recovers the Jones matrix, but requires polarisation analysis after the sample, which is impractical for soft X-rays. We introduce physics-informed vector ptychography (PIVP), which embeds the resonant scattering formalism in the ptychographic forward model, parameterising the Jones matrix by the local order parameter and removing the need for a downstream analyser. We demonstrate PIVP for the Néel vector of an antiferromagnet using simulated data for the proposed Diamond-II CSXID beamline, recovering the complete Néel field. We also demonstrate that, for this set of parameters, the fidelity of this approach is superior to conventional scalar reconstructions.