Date
2017
Abstract
We have experimentally investigated the enhancement in spatial resolution by image subtraction in mid-infrared central solid-immersion lens (c-SIL) microscopy. The subtraction exploits a first image measured with the c-SIL point-spread function (PSF) realized with a Gaussian beam and a second image measured with the beam optically patterned by a silicon it-step phase plate, to realize a centrally hollow PSF. The intense sides lobes in both PSFs that are intrinsic to the SIL make the conventional weighted subtraction methods inadequate. A spatial-domain filter with a kernel optimized to match both experimental PSFs in their periphery was thus developed to modify the first image prior to subtraction, and this resulted in greatly improved performance, with polystyrene beads 1.4 0.1 mu m apart optically resolved with a mid-1R wavelength of 3.4 mu m in water. Spatial-domain filtering is applicable to other PSF pairs, and simulations show that it also outperforms conventional subtraction methods for the Gaussian and doughnut beams widely used in visible and near-1R microscopy. (C) 2017 Optical Society of America
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Description
peer-reviewed
Publisher
Optical Society of America
Citation
Optics Express;25 (12), pp. 1345-1352
Collections
Physics
Bernal Institute
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Silien_2017_spatial.pdf
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Keywords
contrast enhancement, confocal microscopy, resolution enhancement, vector beams, limit
ULRR Identifiers
https://hdl.handle.net/10344/6628
 https://doi.org/10.34961/4540
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Funding Information
European Research Council (ERC), Science Foundation Ireland (SFI), Irish Research Council (IRC), INSPIRE
Sustainable Development Goals
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