title: Depth of focus enhancement of a modified imaging quasi-fractal zone plate.
abstract: We propose a new parameterwfor optimization of foci distribution of conventional fractal zone plates (FZPs) with a greater depth of focus (DOF) in imaging. Numerical simulations of DOF distribution on axis directions indicate that the values of DOF can be extended by a factor of 1.5 or more by a modified quasi-FZP. In experiments, we employ a simple object-lens-image-plane arrangement to pick up images at various positions within the DOF of a conventional FZP and a quasi-FZP, respectively. Experimental results show that the parameterwimproves foci distribution of FZPs in good agreement with theoretical predictions.
authors.affiliation: Institute of Modern Optics, Key Laboratory of Optical Information Technical Science, Ministry of Education of China, Nankai University, Tianjin 300071, China.
authors.forename: Qinqin
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jingang
authors.initials: J
authors.lastname: Wang
authors.forename: Mingwei
authors.initials: M
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Bu
authors.forename: Siwei
authors.initials: S
authors.lastname: Zhu
authors.forename: Bruce Z
authors.initials: BZ
authors.lastname: Gao
authors.forename: Xiaocong
authors.initials: X
authors.lastname: Yuan
keywords: DOF; Fractal zone plate; Quasi-FZP