Soft x-ray linear dichroic ptychography: the study of crystal orientation in biominerals

Here we present soft X-ray linear dichroic ptychography developed at the COherent Scattering and MICroscopy (COSMIC) beamline at the Advanced Light Source (ALS) by studying biominerals—complex 3D hierarchically structured mineral-organic composite materials—produced by living organisms. Sequences of soft x-ray ptychography images at varying EPU polarizations were acquired, which principally allows visualization and orientation mapping of complex biogenic ultrastructures with spatial resolution down to 8 nm. These correlative data not only shed light on key mechanisms of the formation and mechanical principles of these composites but also demonstrate the capabilities and limitations of this newly developed technique, such as orientational precision, angular resolution and thickness related restrictions.