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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 three dielectric-core-gold-shell nanocylinder pairs on dimensions. (a) The dependence of the extinction spectra on the pair distance between the three nanocylinder pairs. (b) For the pair distance of 20 nm, the electric field intensity at the wavelength of 979 nm. (c) For the pair distance of 20 nm, the electric field intensity at the wavelength of 1218 nm.
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Figure 5: The dependence of the extinction spectra of three dielectric-core-gold-shell nanocylinder pairs on dimensions. (a) The dependence of the extinction spectra on the pair distance between the three nanocylinder pairs. (b) For the pair distance of 20 nm, the electric field intensity at the wavelength of 979 nm. (c) For the pair distance of 20 nm, the electric field intensity at the wavelength of 1218 nm.

Mentions: The simulation results of the three nanocylinder pairs with different pair-distances p from 20 to 2 nm are shown in Figure 5a, and the spectra become more complex. Two lightning-rod plasmon modes can be found in the infrared range in the extinction spectra and the resonance wavelengths are 979 and 1218 nm, respectively. From the electric intensity of these two plasmon modes shown in Figure 5b, c, one can be convinced that the two plasmon modes are due to the dipolar coupling of three solid metallic pairs but with different charge distributions. A very interesting situation occurs when the wavelength of the incident light is 979 nm, in which case the maximum electric field intensity occurs in the gap of the second pair. Ng and Liu [15,16] pointed out that a cavity mode confined by three nanocylinder pairs can be found in the plasmonic spectra of the three-pair metallic nanocylinders. In this experiment, it is found that such a cavity mode of three solid nanocylinder pairs is essentially the same as the lightning-rod mode of approximately 979 nm. Therefore, the multiple core-shell nanocylinder pairs show higher tenability than those of the solid nanocylinder pairs and the properties of the lighting-rod plasmon mode of three core-shell nanocylinder pairs are known


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 three dielectric-core-gold-shell nanocylinder pairs on dimensions. (a) The dependence of the extinction spectra on the pair distance between the three nanocylinder pairs. (b) For the pair distance of 20 nm, the electric field intensity at the wavelength of 979 nm. (c) For the pair distance of 20 nm, the electric field intensity at the wavelength of 1218 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: The dependence of the extinction spectra of three dielectric-core-gold-shell nanocylinder pairs on dimensions. (a) The dependence of the extinction spectra on the pair distance between the three nanocylinder pairs. (b) For the pair distance of 20 nm, the electric field intensity at the wavelength of 979 nm. (c) For the pair distance of 20 nm, the electric field intensity at the wavelength of 1218 nm.
Mentions: The simulation results of the three nanocylinder pairs with different pair-distances p from 20 to 2 nm are shown in Figure 5a, and the spectra become more complex. Two lightning-rod plasmon modes can be found in the infrared range in the extinction spectra and the resonance wavelengths are 979 and 1218 nm, respectively. From the electric intensity of these two plasmon modes shown in Figure 5b, c, one can be convinced that the two plasmon modes are due to the dipolar coupling of three solid metallic pairs but with different charge distributions. A very interesting situation occurs when the wavelength of the incident light is 979 nm, in which case the maximum electric field intensity occurs in the gap of the second pair. Ng and Liu [15,16] pointed out that a cavity mode confined by three nanocylinder pairs can be found in the plasmonic spectra of the three-pair metallic nanocylinders. In this experiment, it is found that such a cavity mode of three solid nanocylinder pairs is essentially the same as the lightning-rod mode of approximately 979 nm. Therefore, the multiple core-shell nanocylinder pairs show higher tenability than those of the solid nanocylinder pairs and the properties of the lighting-rod plasmon mode of three core-shell nanocylinder pairs are known

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