title: Super-resolution of fluorescence-free plasmonic nanoparticles using enhanced dark-field illumination based on wavelength-modulation.
abstract: Super-resolution imaging of fluorescence-free plasmonic nanoparticles (NPs) was achieved using enhanced dark-field (EDF) illumination based on wavelength-modulation. Indistinguishable adjacent EDF images of 103-nm gold nanoparticles (GNPs), 40-nm gold nanorods (GNRs), and 80-nm silver nanoparticles (SNPs) were modulated at their wavelengths of specific localized surface plasmon scattering. The coordinates (x, y) of each NP were resolved by fitting their point spread functions with a two-dimensional Gaussian. The measured localization precisions of GNPs, GNRs, and SNPs were 2.5 nm, 5.0 nm, and 2.9 nm, respectively. From the resolved coordinates of NPs and the corresponding localization precisions, super-resolution images were reconstructed. Depending on the spontaneous polarization of GNR scattering, the orientation angle of GNRs in two-dimensions was resolved and provided more elaborate localization information. This novel fluorescence-free super-resolution method was applied to live HeLa cells to resolve NPs and provided remarkable sub-diffraction limit images.
authors.affiliation: Department of Chemistry, Graduate School, Kyung Hee University, Yongin-si, Gyeonggi-do 446-701, Korea.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Applied Chemistry and Institute of Natural Sciences, Kyung Hee University, Yongin-si, Gyeonggi-do 446-701, Korea.
authors.forename: Seungah
authors.initials: S
authors.lastname: Lee
authors.affiliation: Center for Nanometrology, Korea Research Institute of Standards and Science, Daejeon 305-340, Korea.
authors.forename: Hyunung
authors.initials: H
authors.lastname: Yu
authors.affiliation: Ames Laboratory-US Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: Ning
authors.initials: N
authors.lastname: Fang
authors.affiliation: 1] Department of Chemistry, Graduate School, Kyung Hee University, Yongin-si, Gyeonggi-do 446-701, Korea [2] Department of Applied Chemistry and Institute of Natural Sciences, Kyung Hee University, Yongin-si, Gyeonggi-do 446-701, Korea.
authors.forename: Seong Ho
authors.initials: SH
authors.lastname: Kang