Research on partially coherent light propagation through zone plates

The MOI (mutual optical intensity) model is further developed and extended to analyze the mutual optical intensity propagation through a zone plate. This is the first study to quantitatively analyze the influence of the partial coherence property on the spatial resolution of zone plates. Increasing the source coherence length is beneficial for improving the spatial resolution of the zone plate; however, apparent diffraction peaks are observed at the focal plane. Reducing the sizes of the central stop and the order selecting aperture (OSA) can improve the signal-to-noise (SNR) ratio at the cost of the photon flux. Furthermore, we analyze the coherence property propagation through the STXM beamline at Shanghai Synchrotron Radiation Facility (SSRF), where a zone plate is used to focus the light into similar to 30 nm. The coherence property increases and the photon flux decreases with decreasing exit slit size, which is beneficial for improving the spatial resolution of the zone plate. Therefore, the spatial resolution and flux can be balanced by optimizing the exit slit size. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement