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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 FDTD-calculated extinction, scattering, and absorption spectra of a dielectric-core-gold-shell nanocylinder pair with a separation distance of 20 nm. The permittivity of the dielectric core is 2.1. The light incident geometry is shown in the inset.
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Figure 1: The FDTD-calculated extinction, scattering, and absorption spectra of a dielectric-core-gold-shell nanocylinder pair with a separation distance of 20 nm. The permittivity of the dielectric core is 2.1. The light incident geometry is shown in the inset.

Mentions: The spectral characteristics of a single dielectric-core-gold-shell nanocylinder pair are first investigated. The geometry of the nanocylinder is shown in the inset of Figure 1, and the distance between the nanocylinders is 20 nm. The dielectric constant of the dielectric core inside the nanocylinder is 2.1, which is the dielectric constant of the silica. From Figure 1, it can be seen that the extinction spectrum is characterized by two plasmon modes. The plasmon mode, of approximately 700 nm, corresponds to in-phase symmetric dipole-dipole interaction mode, and the symmetric dipole mode is a result of the electrons at the inner surface of the core-shell nanocylinder aligned symmetrically with the electrons at the outer surface [21].


Multiple metallic-shell nanocylinders for surface-enhanced spectroscopes.

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

The FDTD-calculated extinction, scattering, and absorption spectra of a dielectric-core-gold-shell nanocylinder pair with a separation distance of 20 nm. The permittivity of the dielectric core is 2.1. The light incident geometry is shown in the inset.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: The FDTD-calculated extinction, scattering, and absorption spectra of a dielectric-core-gold-shell nanocylinder pair with a separation distance of 20 nm. The permittivity of the dielectric core is 2.1. The light incident geometry is shown in the inset.
Mentions: The spectral characteristics of a single dielectric-core-gold-shell nanocylinder pair are first investigated. The geometry of the nanocylinder is shown in the inset of Figure 1, and the distance between the nanocylinders is 20 nm. The dielectric constant of the dielectric core inside the nanocylinder is 2.1, which is the dielectric constant of the silica. From Figure 1, it can be seen that the extinction spectrum is characterized by two plasmon modes. The plasmon mode, of approximately 700 nm, corresponds to in-phase symmetric dipole-dipole interaction mode, and the symmetric dipole mode is a result of the electrons at the inner surface of the core-shell nanocylinder aligned symmetrically with the electrons at the outer surface [21].

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