Resolution enhancement with highly curved illumination in ptychography

By deducing a formula to compute a sample from recorded diffraction intensity directly and analytically, the relationship among the highest reachable resolution of the ptychographic iterative engine (PIE), its illumination angle, and its collection angle was discussed analytically. Curved illumination was then proposed to realize the resolution enhancement for PIE, and a corresponding computing algorithm was proposed to avoid an undersampling effect without increasing the size of the computing matrix, thus realizing speedy high-resolution PIE imaging with a simple experimental setup. While theoretical analysis was carried out, the feasibility of this proposed method was verified both numerically and experimentally.