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Effects of corner radius on periodic nanoantenna for surface-enhanced Raman spectroscopy
- Source :
- Journal of Optics. 17:125002
- Publication Year :
- 2015
- Publisher :
- IOP Publishing, 2015.
-
Abstract
- Corner radius is a concept to approximate the fabrication limitation due to the effective beam broadening at the corner in using electron-beam lithography. The purpose of the present study is to investigate the effects of corner radius on the electromagnetic field enhancement and resonance wavelength for three periodic polygon dimers of bowtie, twin square, and twin pentagon. The enhancement factor of surface-enhanced Raman spectroscopy due to the localized surface plasmon resonances in fabricated gold bowtie nanostructures was investigated using both Raman spectroscopy and finite-difference time-domain simulations. The simulated enhancement factor versus corner radius relation was in agreement with measurements and it could be fitted by a power-law relation. In addition, the resonance wavelength showed blue shift with the increasing corner radius because of the distribution of concentrated charges in a larger area. For different polygons, the corner radius instead of the tip angle is the dominant factor of the electromagnetic field enhancement because the surface charges tend to localize at the corner. Greater enhancements can be obtained by having both the smaller gap and sharper corner although the corner radius effect on intensity enhancement is less than the gap size effect.
- Subjects :
- Electromagnetic field
Materials science
business.industry
Surface-enhanced Raman spectroscopy
Atomic and Molecular Physics, and Optics
Electronic, Optical and Magnetic Materials
Blueshift
symbols.namesake
Optics
symbols
Surface charge
Raman spectroscopy
business
Lithography
Intensity (heat transfer)
Localized surface plasmon
Subjects
Details
- ISSN :
- 20408986 and 20408978
- Volume :
- 17
- Database :
- OpenAIRE
- Journal :
- Journal of Optics
- Accession number :
- edsair.doi...........5d80327e95c0510b9795aefecc38b303