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Implementation of free-space Fourier Ptychography with near maximum system numerical aperture

Liang, Mingshu and Yang, Changhuei (2022) Implementation of free-space Fourier Ptychography with near maximum system numerical aperture. Optics Express, 30 (12). pp. 20321-20332. ISSN 1094-4087. doi:10.1364/oe.459833.

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Over the past decade, the research field of Fourier Ptychographic Microscopy (FPM) has seen numerous innovative developments that significantly expands its utility. Here, we report a high numerical aperture (NA) FPM implementation that incorporates some of these innovations to achieve a synthetic NA of 1.9 – close to the maximum possible synthetic NA of 2 for a free space FPM system. At this high synthetic NA, we experimentally found that it is vital to homogenize the illumination field in order to achieve the best resolution. Our FPM implementation has a full pitch resolution of 266 nm for 465 nm light, and depth of field of 3.6 µm. In comparison, a standard transmission microscope (incoherent) with close to maximum possible NA of 0.95 has a full pitch resolution of 318 nm for 465 nm light, and depth of field of 0.65 µm. While it is generally assumed that a free-space coherent imaging system and a free-space incoherent imaging system operating at their respective maximum NA should give comparable resolution, we experimentally find that an FPM system significantly outperforms its incoherent standard microscopy counterpart in resolution by a factor of 20%. Coupled with FPM’s substantially longer effective depth of field (5.5 times longer), our work indicates that, in the near-maximum NA operation regime, the FPM has significant resolution and depth of field advantages over incoherent standard microscopy.

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Yang, Changhuei0000-0001-8791-0354
Additional Information:© 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement. Received 4 Apr 2022; revised 6 May 2022; accepted 14 May 2022; published 23 May 2022. The LED quasi-dome used in this paper was generously donated by Laura Waller’s research group from University of California, Berkeley. The authors thank Cheng Shen for helpful discussion about illumination correction methods and depth of field of high-NA FPM. Funding. Merkin Institute for Translational Research (13520291); National Institutes of Health (CA233363). Data availability. Data underlying the results presented in this paper are not publicly available at this time but may be obtained from the authors upon reasonable request. The authors declare no conflicts of interest.
Group:Richard N. Merkin Institute for Translational Research
Funding AgencyGrant Number
Caltech Merkin Institute for Translational Research13520291
Issue or Number:12
Record Number:CaltechAUTHORS:20220722-768660000
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Official Citation:Mingshu Liang and Changhuei Yang, "Implementation of free-space Fourier Ptychography with near maximum system numerical aperture," Opt. Express 30, 20321-20332 (2022)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:115762
Deposited By: George Porter
Deposited On:25 Jul 2022 19:34
Last Modified:25 Jul 2022 19:34

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