Full-field x-ray fluorescence imaging using a Fresnel zone plate coded aperture

We present an approach to full-field x-ray fluorescence imaging that uses a Fresnel zone plate as a coded aperture positioned between the object and detector. For this particular coded aperture, the incoherent image formation is identical to the coherent propagation image (inline hologram) of an equivalent absorption object. In a first experiment, we show that prior knowledge of the coded aperture structure and position are no longer required. Fast and robust reconstruction algorithms well known from coherent imaging can be applied. We demonstrate the approach using x-ray fluorescence excited by a collimated Cu-Kalpha beam at an ordinary laboratory x-ray source. Images are recorded with a field of view of 1mm2 and a resolution of 35µm.The simple and efficient imaging scheme is well suited for further dissemination of x-ray fluorescence imaging and translation to a broader user community which could take advantage of full-field imaging with chemical contrast. More generally, the scheme also enables full-field imaging of other incoherent radiation processes, for which lenses are either not available at all or not with sufficient numerical aperture. Examples include Compton imaging, imaging of inelastic neutron scattering, or gamma-ray imaging in nuclear medicine.