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Anisotropy modeling of terahertz metamaterials: polarization dependent resonance manipulation by meta-atom cluster.

Jung H, In C, Choi H, Lee H - Sci Rep (2014)

Bottom Line: Most metamaterials are known to have anisotropic properties, but existing anisotropy models are applicable only to a single meta-atom and its properties.Here we propose an anisotropy model for asymmetrical meta-atom clusters and their polarization dependency.The proposed anisotropic meta-atom clusters show a unique resonance property in which their frequencies can be altered for parallel polarization, but fixed to a single resonance frequency for perpendicular polarization.

View Article: PubMed Central - PubMed

Affiliation: 1] School of Electronic Engineering, Soongsil University, Seoul 156-743, Korea [2].

ABSTRACT
Recently metamaterials have inspired worldwide researches due to their exotic properties in transmitting, reflecting, absorbing or refracting specific electromagnetic waves. Most metamaterials are known to have anisotropic properties, but existing anisotropy models are applicable only to a single meta-atom and its properties. Here we propose an anisotropy model for asymmetrical meta-atom clusters and their polarization dependency. The proposed anisotropic meta-atom clusters show a unique resonance property in which their frequencies can be altered for parallel polarization, but fixed to a single resonance frequency for perpendicular polarization. The proposed anisotropic metamaterials are expected to pave the way for novel optical systems.

No MeSH data available.


Related in: MedlinePlus

The induced current distributions in various meta-atoms.Simulated (a) surface current distributions and (b) transmission spectra of various metamaterials from the conventional SRR to the H-shaped meta-atoms by shifting the center bar position by 2 μm. The 20 by 20-μm unit cell has a 4-μm line width. The incident electric field is polarized parallel to the gap of the unit cells. ωf and ωh represent the resonance frequencies on the inner and outer sides of the induced unit cells, respectively.
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f2: The induced current distributions in various meta-atoms.Simulated (a) surface current distributions and (b) transmission spectra of various metamaterials from the conventional SRR to the H-shaped meta-atoms by shifting the center bar position by 2 μm. The 20 by 20-μm unit cell has a 4-μm line width. The incident electric field is polarized parallel to the gap of the unit cells. ωf and ωh represent the resonance frequencies on the inner and outer sides of the induced unit cells, respectively.

Mentions: Although the variations of the resonance frequencies ωf and ωc can be explained by the direction of excited metal lines and their resulting charge collisions, the higher order resonance frequency ωh for all meta-atoms cannot be explained either by a third order resonance or by the excited charge collision, as discussed above. In order to investigate the origin of the higher resonances for the parallel polarization in the SSR structure, we simulated the surface current distributions on various meta-atom structures from those with the conventional SRR to those with the H-shaped40 meta-atoms by shifting the center bar position by 2 μm, as shown in Figure 2. As shown in Figure 2a, the induced currents of all the meta-atoms were concentrated on the inner side of the structure at ωf, but were concentrated on the opposite side at ωh.


Anisotropy modeling of terahertz metamaterials: polarization dependent resonance manipulation by meta-atom cluster.

Jung H, In C, Choi H, Lee H - Sci Rep (2014)

The induced current distributions in various meta-atoms.Simulated (a) surface current distributions and (b) transmission spectra of various metamaterials from the conventional SRR to the H-shaped meta-atoms by shifting the center bar position by 2 μm. The 20 by 20-μm unit cell has a 4-μm line width. The incident electric field is polarized parallel to the gap of the unit cells. ωf and ωh represent the resonance frequencies on the inner and outer sides of the induced unit cells, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048888&req=5

f2: The induced current distributions in various meta-atoms.Simulated (a) surface current distributions and (b) transmission spectra of various metamaterials from the conventional SRR to the H-shaped meta-atoms by shifting the center bar position by 2 μm. The 20 by 20-μm unit cell has a 4-μm line width. The incident electric field is polarized parallel to the gap of the unit cells. ωf and ωh represent the resonance frequencies on the inner and outer sides of the induced unit cells, respectively.
Mentions: Although the variations of the resonance frequencies ωf and ωc can be explained by the direction of excited metal lines and their resulting charge collisions, the higher order resonance frequency ωh for all meta-atoms cannot be explained either by a third order resonance or by the excited charge collision, as discussed above. In order to investigate the origin of the higher resonances for the parallel polarization in the SSR structure, we simulated the surface current distributions on various meta-atom structures from those with the conventional SRR to those with the H-shaped40 meta-atoms by shifting the center bar position by 2 μm, as shown in Figure 2. As shown in Figure 2a, the induced currents of all the meta-atoms were concentrated on the inner side of the structure at ωf, but were concentrated on the opposite side at ωh.

Bottom Line: Most metamaterials are known to have anisotropic properties, but existing anisotropy models are applicable only to a single meta-atom and its properties.Here we propose an anisotropy model for asymmetrical meta-atom clusters and their polarization dependency.The proposed anisotropic meta-atom clusters show a unique resonance property in which their frequencies can be altered for parallel polarization, but fixed to a single resonance frequency for perpendicular polarization.

View Article: PubMed Central - PubMed

Affiliation: 1] School of Electronic Engineering, Soongsil University, Seoul 156-743, Korea [2].

ABSTRACT
Recently metamaterials have inspired worldwide researches due to their exotic properties in transmitting, reflecting, absorbing or refracting specific electromagnetic waves. Most metamaterials are known to have anisotropic properties, but existing anisotropy models are applicable only to a single meta-atom and its properties. Here we propose an anisotropy model for asymmetrical meta-atom clusters and their polarization dependency. The proposed anisotropic meta-atom clusters show a unique resonance property in which their frequencies can be altered for parallel polarization, but fixed to a single resonance frequency for perpendicular polarization. The proposed anisotropic metamaterials are expected to pave the way for novel optical systems.

No MeSH data available.


Related in: MedlinePlus