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Proceedings Paper

Structured illumination microscopy for vibrational molecular imaging (Conference Presentation)

Paper Abstract

Raman microscopy is a powerful tool for analytical imaging. The wavelength shift of Raman scattering corresponds to molecular vibrational energy. Therefore, we can access rich chemical information, such as distribution, concentration, and chemical environment of sample molecules. Despite these strengths of Raman microscopy, the spatial resolution has been a limiting factor for many practical applications. In this study, we developed a large-area, high-resolution Raman microscope by utilizing structured illumination microscopy (SIM) to overcome the spatial resolution limit. A structured line-illumination (SLI) Raman microscope was constructed. The structured illumination is introduced along the line direction by the interference of two line-shaped beams. In SIM, the spatial frequency mixing between structured illumination and Raman scattering from the sample allows access to the high spatial frequency information beyond the conventional cut-off. As a result, the FWHM of 40-nm fluorescence particle images showed a clear resolution enhancement in the line direction: 366 nm in LI and 199 nm in SLI microscope. Using the developed microscope, we successfully demonstrated high-resolution Raman imaging of various kinds of specimens, such as few-layer graphene, graphite, mouse brain tissue, and polymer nanoparticles. The high resolution Raman images showed the capability to extract original spectral features from the mixed Raman spectra of a multi-component sample because of the enhanced spatial resolution, which is advantageous in observing complex spectral features. The Raman microscopy technique reported here enables us to see the detailed chemical structures of chemical, biological, and medical samples with a spatial resolution smaller than 200 nm.

Paper Details

Date Published: 3 November 2016
PDF: 1 pages
Proc. SPIE 9925, Nanoimaging and Nanospectroscopy IV, 992504 (3 November 2016); doi: 10.1117/12.2239007
Show Author Affiliations
Kozue Watanabe, Osaka Univ. (Japan)
Almar F. Palonpon, Osaka Univ. (Japan)
Nicholas I. Smith, Osaka Univ. (Japan)
Liang-da Chiu, The Univ. of Tokyo (Japan)
Atsushi Kasai, Osaka Univ. (Japan)
Hitoshi Hashimoto, Osaka Univ. (Japan)
Satoshi Kawata, Osaka Univ. (Japan)
Katsumasa Fujita, Osaka Univ. (Japan)

Published in SPIE Proceedings Vol. 9925:
Nanoimaging and Nanospectroscopy IV
Prabhat Verma; Alexander Egner, Editor(s)

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