Fast Simulation of Wide-Angle Coherent Diffractive Imaging

Abstract: Single-shot coherent diffractive imaging (CDI) using intense XUV and soft X-ray pulses holds the promise to deliver information on the three dimensional shape as well as the optical properties of nano-scale objects in a single diffraction image. This advantage over conventional X-ray diffraction methods comes at the cost of a much more complex description of the underlying scattering process due to the importance of wide-angle scattering and propagation effects.The commonly employed reconstruction of the sample properties via iterative forward fitting of diffraction patterns requires an accurate and fast method to simulate the scattering process. This work introduces the propagation multi-slice Fourier transform method (pMSFT) and demonstrates its superior performance and accuracy against existing methods for wide-angle scattering. A derivation from first principles, a unified physical picture of the approximations underlying pMSFT and the existing methods, as well as a systematic benchmark that provides qualified guidance for the selection of the appropriate scattering method is presented.