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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.


Related in: MedlinePlus

The dependence of the extinction spectra of two dielectric-core-gold-shell nanocylinder pairs on dimensions. (a) For different gap widths between the nanocylinders with the pair distance p of 20 nm, (b) for different pair-distances between the nanocylinder pairs with the gap width of 20 nm, (c) for different dielectric constant of the dielectric cores, (d) for different surrounding medium.
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Figure 4: The dependence of the extinction spectra of two dielectric-core-gold-shell nanocylinder pairs on dimensions. (a) For different gap widths between the nanocylinders with the pair distance p of 20 nm, (b) for different pair-distances between the nanocylinder pairs with the gap width of 20 nm, (c) for different dielectric constant of the dielectric cores, (d) for different surrounding medium.

Mentions: In the following sections, it is shown that the plasmon modes of the two core-shell nanocylinder pairs can be tuned systematically by varying the gap-width d between the nanocylinder pair, pair-distance p between the pairs, the dielectric constant of the dielectric core inside the nanocylinder, and the surrounding medium. First, the two pairs are simulated by varying the gap-distance d between the nanocylinder pair with the fixed pair-distance of 20 nm as shown in Figure 4a. As the inter-cylinder distance decreases, the lightning-rod plasmon mode is red-shifted and enhanced due to the much stronger interaction of dipolar modes as a result of the electrons at the outer surface of the nanocylinders. As the intensity of this plasmon mode increases, a dramatically larger electric field concentrates in the gap of the nanocylinder pair. As for other plasmon modes that are a result of the interactions of the individual core-shell nanocylinder par plasmon modes, the resonance wavelength and intensity almost remain the same. This is because the cavity mode inside the dielectric core was formed due to the sufficient effective length, which is similar to the one-dimensional Fabre-Perot resonance mode. (Therefore, these plasmon modes associated with the cavity mode do not change dramatically by outside of the nanocylinders.)


Multiple metallic-shell nanocylinders for surface-enhanced spectroscopes.

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

The dependence of the extinction spectra of two dielectric-core-gold-shell nanocylinder pairs on dimensions. (a) For different gap widths between the nanocylinders with the pair distance p of 20 nm, (b) for different pair-distances between the nanocylinder pairs with the gap width of 20 nm, (c) for different dielectric constant of the dielectric cores, (d) for different surrounding medium.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: The dependence of the extinction spectra of two dielectric-core-gold-shell nanocylinder pairs on dimensions. (a) For different gap widths between the nanocylinders with the pair distance p of 20 nm, (b) for different pair-distances between the nanocylinder pairs with the gap width of 20 nm, (c) for different dielectric constant of the dielectric cores, (d) for different surrounding medium.
Mentions: In the following sections, it is shown that the plasmon modes of the two core-shell nanocylinder pairs can be tuned systematically by varying the gap-width d between the nanocylinder pair, pair-distance p between the pairs, the dielectric constant of the dielectric core inside the nanocylinder, and the surrounding medium. First, the two pairs are simulated by varying the gap-distance d between the nanocylinder pair with the fixed pair-distance of 20 nm as shown in Figure 4a. As the inter-cylinder distance decreases, the lightning-rod plasmon mode is red-shifted and enhanced due to the much stronger interaction of dipolar modes as a result of the electrons at the outer surface of the nanocylinders. As the intensity of this plasmon mode increases, a dramatically larger electric field concentrates in the gap of the nanocylinder pair. As for other plasmon modes that are a result of the interactions of the individual core-shell nanocylinder par plasmon modes, the resonance wavelength and intensity almost remain the same. This is because the cavity mode inside the dielectric core was formed due to the sufficient effective length, which is similar to the one-dimensional Fabre-Perot resonance mode. (Therefore, these plasmon modes associated with the cavity mode do not change dramatically by outside of the nanocylinders.)

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.


Related in: MedlinePlus