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Fluorescence correlation spectroscopy using an optical scattering probe based on plasmonic dimer antenna arrays (Conference Presentation)
Author(s): Hongki Lee; Donghyun Kim; Seongmin Im; Gwiyeong Moon
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Paper Abstract

We have investigated the excitation of fluoresce molecules using nanoscale light confinement on the plasmonic nanostructures. We have fabricated gold nano-dimer arrays whose diameter and height were 100 and 20 nm respectively on 20-nm gold film with BK7 substrate with a period of 746 nm. We have calculated the field distribution by three dimensional finite-difference time-domain (FDTD) method and confirmed the field localization on the dimer’s gap whose size was 18 nm. The field confinement was induced by a light source at 671 nm and experimentally measured by near-field scanning optical microscopy (NSOM) under same incident condition given at FDTD calculation. The angle of surface plasmon resonance (SPR) was chosen to enable both fluorescence microscopy and SPR microscopy simultaneously. Given a resonance angle, a dimer could provide a subdiffraction-limited observation volume to study the dynamics of fluorescence molecules and a highly sensitive light scattering probe as a nanoantenna. By employing dual microscopic images, we could separate the fluorescence excitations within a subdiffracion-limited volume from those outside the volume. We calculated scattering intensities of fluorescence nanobeads on the dimer nanoantenna to assure the presence within an observation volume when they diffuse near the dimer nanoantenna with Brownian motion. We have applied the subdiffraction-limited volume to fluorescence correlation spectroscopy (FCS) to measure the dynamics of fluorescence molecules with high signal-to-noise ratio, with additional spatial analysis from SPR microscopy. The result of imaging FCS using gold nano-dimer with SPR microscopy shows novel applications for nanoscale sensing and imaging methods.

Paper Details

Date Published: 13 March 2019
Proc. SPIE 10891, Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XVI, 108910P (13 March 2019); doi: 10.1117/12.2509830
Show Author Affiliations
Hongki Lee, Yonsei Univ. (Korea, Republic of)
Donghyun Kim, Yonsei Univ. (Korea, Republic of)
Seongmin Im, Yonsei Univ. (Korea, Republic of)
Gwiyeong Moon, Yonsei Univ. (Korea, Republic of)

Published in SPIE Proceedings Vol. 10891:
Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XVI
Dan V. Nicolau; Dror Fixler; Ewa M. Goldys, Editor(s)

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