Rapid and high-accuracy oblique-illuminated reflective ptychography without pre-correction

Abstract

Ptychography offers several advantages, including a lensless design, a simple optical setup, high spatial resolution, and the elimination of the need for high-quality optical components. In applications like surface topography measurement, ptychography setups are typically configured in reflective mode. However, existing studies indicate that normal-incidence configurations are often complex and constrained by the arrangement of beam splitters. Furthermore, tilted illumination with vertical detection typically involves tilted plane correction methods for pre-correcting diffraction patterns or by developing more refined models, which can degrade reconstruction accuracy and increase computational overhead. This study derives a forward propagation model for reflective off-axis diffraction, where the beam maintains the same angle relative to both the sample plane and the recording plane, thereby eliminating the need for a pre-correction process. Based on our propagation model, we developed a regularized ptychography iterative engine combined with a total variation denoising algorithm, effectively suppressing sensor noise and potential experimental inaccuracies. Reflective samples were successfully reconstructed, and comparisons with pre-correction methods on USAF 1951 targets demonstrated a significant improvement in reconstruction speed as well as enhanced accuracy. Finally, the proposed method accurately retrieved the surface morphology of atomic force microscope test samples.