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Multiple metallic-shell nanocylinders for surface-enhanced spectroscopes.

Lu JY, Chiu KP, Chao HY, Chang YH - Nanoscale Res Lett (2011)

Bottom Line: The resonance wavelength and local field enhancement of this plasmon mode can be tuned by varying the pair-distance between the pairs, the gap-distance between the pairs, and the optical constants of the dielectric-core and the surrounding medium.The results show that the multiple core-shell nanocylinder pair contains the plasmon mode same as that of the solid metallic cylinder pairs at the long wavelength part of the spectrum.The large electric field intensity in the infrared region at long wavelength makes multiple core-shell cylinders as ideal candidates for surface-enhanced spectroscopes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics, National Taiwan University, Taiwan. yuanhuei@ntu.edu.tw.

ABSTRACT
The optical properties of multiple dielectric-core-gold-shell nanocylinder pairs are investigated by two-dimensional finite difference time domain method. The core-shell cylinders are assumed to be of the same dimension and composition. For normal incidence, the diffraction spectra of multiple cylinder pairs contain the lightning-rod plasmon mode, and the electric field intensity is concentrated in the gap between the nanocylinder pairs in the infrared region. The resonance wavelength and local field enhancement of this plasmon mode can be tuned by varying the pair-distance between the pairs, the gap-distance between the pairs, and the optical constants of the dielectric-core and the surrounding medium. The results show that the multiple core-shell nanocylinder pair contains the plasmon mode same as that of the solid metallic cylinder pairs at the long wavelength part of the spectrum. The large electric field intensity in the infrared region at long wavelength makes multiple core-shell cylinders as ideal candidates for surface-enhanced spectroscopes.

No MeSH data available.


The extinction spectra of two silica-core gold-shell nanocylinder pairs with the gap width of 20 nm and pair-distance of 20 nm.
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Figure 2: The extinction spectra of two silica-core gold-shell nanocylinder pairs with the gap width of 20 nm and pair-distance of 20 nm.

Mentions: When two core-shell nanocylinder pairs are brought together with the pair distance p of 20 nm, the interaction between the two nanocylinder pairs is strong and results in the energy splitting in the spectrum. The other parameters are the same as those shown in Figure 1. The plasmon modes of two nanocylinder pairs are unveiled in Figure 2, which shows four major plasmon modes in the spectra between the visible and infrared regions. The plasmon mode, of approximately 800 nm, corresponds to the two in-phase symmetric dipole-dipole modes oscillating in the out-of-phase way. In other words, when two nanocylinder pairs couple with each other, the in-phase symmetric dipole mode of a single dielectric-core-gold-shell interacts with that of another nanocylinder pair. Phase retardation effect results in the out-of-phase oscillation for the two in-phase symmetrical dipole-dipole modes [22].


Multiple metallic-shell nanocylinders for surface-enhanced spectroscopes.

Lu JY, Chiu KP, Chao HY, Chang YH - Nanoscale Res Lett (2011)

The extinction spectra of two silica-core gold-shell nanocylinder pairs with the gap width of 20 nm and pair-distance of 20 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211226&req=5

Figure 2: The extinction spectra of two silica-core gold-shell nanocylinder pairs with the gap width of 20 nm and pair-distance of 20 nm.
Mentions: When two core-shell nanocylinder pairs are brought together with the pair distance p of 20 nm, the interaction between the two nanocylinder pairs is strong and results in the energy splitting in the spectrum. The other parameters are the same as those shown in Figure 1. The plasmon modes of two nanocylinder pairs are unveiled in Figure 2, which shows four major plasmon modes in the spectra between the visible and infrared regions. The plasmon mode, of approximately 800 nm, corresponds to the two in-phase symmetric dipole-dipole modes oscillating in the out-of-phase way. In other words, when two nanocylinder pairs couple with each other, the in-phase symmetric dipole mode of a single dielectric-core-gold-shell interacts with that of another nanocylinder pair. Phase retardation effect results in the out-of-phase oscillation for the two in-phase symmetrical dipole-dipole modes [22].

Bottom Line: The resonance wavelength and local field enhancement of this plasmon mode can be tuned by varying the pair-distance between the pairs, the gap-distance between the pairs, and the optical constants of the dielectric-core and the surrounding medium.The results show that the multiple core-shell nanocylinder pair contains the plasmon mode same as that of the solid metallic cylinder pairs at the long wavelength part of the spectrum.The large electric field intensity in the infrared region at long wavelength makes multiple core-shell cylinders as ideal candidates for surface-enhanced spectroscopes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics, National Taiwan University, Taiwan. yuanhuei@ntu.edu.tw.

ABSTRACT
The optical properties of multiple dielectric-core-gold-shell nanocylinder pairs are investigated by two-dimensional finite difference time domain method. The core-shell cylinders are assumed to be of the same dimension and composition. For normal incidence, the diffraction spectra of multiple cylinder pairs contain the lightning-rod plasmon mode, and the electric field intensity is concentrated in the gap between the nanocylinder pairs in the infrared region. The resonance wavelength and local field enhancement of this plasmon mode can be tuned by varying the pair-distance between the pairs, the gap-distance between the pairs, and the optical constants of the dielectric-core and the surrounding medium. The results show that the multiple core-shell nanocylinder pair contains the plasmon mode same as that of the solid metallic cylinder pairs at the long wavelength part of the spectrum. The large electric field intensity in the infrared region at long wavelength makes multiple core-shell cylinders as ideal candidates for surface-enhanced spectroscopes.

No MeSH data available.