Plasmonic nanostructures enable field confinement which is locally amplified within sub-diffraction limited volume. The localized near-field can be useful in many biomedical sensing and imaging applications. In this research, we present the near-field characteristics localized by plasmonic nano-post arrays for biomedical spectroscopy. Circular gold nano-post arrays were modeled on gold and chrome films fabricated on a glass substrate whose thickness was 50, 20 and 2 nm, respectively. The nano-post arrays were fabricated with an e-beam lithography and a diameter of the post was 250 nm with periods varied as 500, 700, and 900 nm. The field localization produced by nano-posts was induced by angled illumination with a total internal reflection fluorescence microscope objective lens and measured by a near-field scanning optical microscope (NSOM). The NSOM has a tapered fiber probe with a 70-nm aperture and was a continuous-wave laser whose wavelength is 532 nm as light source. Incident TM-polarized light exhibited field localization on one side of an individual gold nano-post. When the direction of light incidence was changed opposite, localized field was switched to the opposite edge of the circular nano-post. We performed 3D finite difference time domain s for the field calculation and confirmed the localized field distribution at given illumination angles. We also discuss the potential applications of plasmonic field localization for analysis of biomolecules, cells, and tissues.
|Title of host publication||Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XIV|
|Editors||Dan V. Nicolau, Dror Fixler, Alexander N. Cartwright|
|Publication status||Published - 2017|
|Event||Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XIV 2017 - San Francisco, United States|
Duration: 2017 Jan 30 → 2017 Feb 1
|Name||Progress in Biomedical Optics and Imaging - Proceedings of SPIE|
|Other||Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XIV 2017|
|Period||17/1/30 → 17/2/1|
Bibliographical noteFunding Information:
This work was mainly supported by the National Research Foundation Grant funded by the Korean Government (NRF-2012R1A4A1029061 and NRF-2015R1A2A1A10052826).
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Radiology Nuclear Medicine and imaging