Depth of focus enhancement of a modified imaging quasi-fractal zone plate

Qinqin Zhang; Jingang Wang; Mingwei Wang; Jing Bu; Siwei Zhu; Bruce Z Gao; Xiaocong Yuan

doi:10.1016/j.optlastec.2012.03.012

Depth of focus enhancement of a modified imaging quasi-fractal zone plate

Opt Laser Technol. 2012 Oct 1;44(7):10.1016/j.optlastec.2012.03.012. doi: 10.1016/j.optlastec.2012.03.012.

Authors

Qinqin Zhang¹, Jingang Wang, Mingwei Wang, Jing Bu, Siwei Zhu, Bruce Z Gao, Xiaocong Yuan

Affiliation

¹ Institute of Modern Optics, Key Laboratory of Optical Information Technical Science, Ministry of Education of China, Nankai University, Tianjin 300071, China.

Abstract

We propose a new parameter w for 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 parameter w improves foci distribution of FZPs in good agreement with theoretical predictions.

Keywords: DOF; Fractal zone plate; Quasi-FZP.

Abstract

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