| 1. |
- Dalarsson, Mariana, et al.
(författare)
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Lossy gradient index metamaterial with sinusoidal periodicity of refractive index : case of constant impedance throughout the structure
- 2011
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Ingår i: J NANOPHOTONICS. - : SPIE-Intl Soc Optical Eng. - 1934-2608. ; 5, s. 051804-
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Tidskriftsartikel (refereegranskat)abstract
- We used an exact analytical approach to investigate the electromagnetic wave propagation across an isotropic metamaterial composite with i. a sinusoidally periodic gradient of the real parts of the effective permittivity and permeability, ii. spatially uniform imaginary parts of the effective permittivity and permeability, and iii. spatially uniform impedance. The real part of the effective refractive index can be positive and negative along the direction of nonhomogeneity. A remarkably simple direct solution for the field distribution was obtained.
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| 2. |
- Fang, Mei, et al.
(författare)
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Designing photonic band gaps in SiO(2)-based face-centered cubic-structured crystals
- 2011
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Ingår i: Journal of nanophotonics. - : SPIE-Intl Soc Optical Eng. - 1934-2608. ; 5, s. 053514-
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Tidskriftsartikel (refereegranskat)abstract
- We designed face-centered cubic-structured (fcc) photonic crystals whose lattice parameters were tuned by varying the size of the constituent spherical silica particles in the range 100 to 520 nm. From wide-angle optical transmission investigations and Gaussian fitting of the absorbance spectra over UV-Vis-Near IR range, we found that in these crystals the Bragg wavelengths of the photonic band gaps (PBGs) corresponding to the reflected crystal planes linearly increase with the size of the spheres as expected. From this data, the average refractive index along the different crystal planes of the fcc structure was found to be in the 1.24 to 1.32 range. The Bragg wavelengths were tuned between 400 and 1100 nm. Thus, photonic crystals of the same structure can be designed to tune the Bragg wavelengths of PBGs by selecting the sphere size. These studies open up possibilities to design a new class of "smart" photonic crystals consisting of dielectric entities of sub-micron silica spheres with added functionality from magnetic or piezoelectric nanoparticles embedded in them.
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| 3. |
- Ozturk, Z. Fatih, et al.
(författare)
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Field enhancement at metallic interfaces due to quantum confinement
- 2011
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Ingår i: J NANOPHOTONICS. - : SPIE-Intl Soc Optical Eng. - 1934-2608. ; 5, s. 051602-
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Tidskriftsartikel (refereegranskat)abstract
- We point out an apparently overlooked consequence of the boundary conditions obeyed by the electric displacement vector at air-metal interfaces: the continuity of the normal component combined with the quantum mechanical penetration of the electron gas in the air implies the existence of a surface on which the dielectric function vanishes. This, in turn, leads to an enhancement of the normal component of the total electric field. We study this effect for a planar metal surface, with the inhomogeneous electron density accounted for by a Jellium model. We also illustrate the effect for equilateral triangular nanoislands via numerical solutions of the appropriate Maxwell equations, and show that the field enhancement is several orders of magnitude larger than what the conventional theory predicts.
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