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Proceedings Paper

Extend focal depth of a tracking lens by phase apodizers
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Paper Abstract

In a conventional particle tracking system, the depth of field is usually very small because of the use of high power imaging lens. The tracking accuracy may also be affected by the smearing of spot image, caused by focal shift. Increasing the focal depth and keeping uniform spot size in the focal region is highly desirable for a high accurate tracking system. In this report, we study the design of phase apdodizer that could be used to increase the focal depth of a tracking lens. The design is based on the requirements by highly accurate tracking that the point-spread function (PSF) of the lens keep an even and concentrated energy distribution when the lens is defocused. To achieve this purpose, a pure phase-shifting apodizer is introduced on the pupil plane of the lens. The function of the apodizer is to control the energy distribution of the 3D diffraction pattern near the focal region and make the effective spot size uniform or minimum variation along optical axis. The pattern of the 3D PSF of the lens with the apodizer shapes closed to a cylinder. New method used to search and optimize the design of the phase apodizer that meet the requirements of a particle tracking system will be studied. Theoretical analysis and numerical simulation are given in support of the method.

Paper Details

Date Published: 14 October 2005
PDF: 8 pages
Proc. SPIE 5962, Optical Design and Engineering II, 596216 (14 October 2005); doi: 10.1117/12.625007
Show Author Affiliations
Xianyang Cai, National Research Council Canada (Canada)
Shoude Chang, National Research Council Canada (Canada)
Costel Flueraru, National Research Council Canada (Canada)

Published in SPIE Proceedings Vol. 5962:
Optical Design and Engineering II
Laurent Mazuray; Rolf Wartmann, Editor(s)

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