A method for measuring diffraction efficiency of Fresnel zone plates

Abstract

Fresnel zone plate (FZP) is the important imaging components of the diffraction image technology, which is regarded as an important development direction for light-weighted and large-diameter space-based telescopes. However, there are some problems need to be solved, such as band structure defects, multistage diffraction characteristics, and the wavefront aberrations. Then the diffraction efficiency of the FZP is greatly reduced, and the imaging quality of the thin film diffraction imaging system is sharply degraded. In this paper, the measurement system for diffraction efficiency of the FZP is designed and the diffraction efficiency of the FZP measurement experiment is carried out. The experimental results show that the diffraction efficiency of two-step FZP is 25.36%, and that of four-step FZP is 35.36%.