Quantitative contrast enhancement imaging for phase retrieval based on synthetic diffraction pattern

Abstract

A quantitative contrast enhancement imaging concept for phase retrieval based on the synthetic diffraction patterns was proposed. A virtual specimen could be retrieved by original phase retrieval algorithms using synthetic diffraction patterns which are compounded from the diffraction patterns both with and without original weak phase specimen. Compared to the original specimen, the amplitude and phase contrast of the virtual specimen were distinctly enhanced while the structures were not changed. The conversion relationships between the virtual and actual specimen were theoretically and quantitatively determined. The validity was demonstrated by simulations and practical experiments with extended ptychographic iterative engine and coherent modulation imaging respectively, and the results agree with the conclusions of the theoretical analysis. The proposed concept provides a simple, universal and practical imaging enhancement technique for existing phase retrieval algorithms with different light sources.