Limits...
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

S-shaped resonator (SSR) array.(a) Schematic and SEM image of the fabricated SSR metamaterial array. The unit cell has dimensions of w = 4 μm, l = 20 μm, and g = s = 12 μm. (b) Simulated surface current distributions of the SSR and SRR unit cells at ωf, ωh and ωc, respectively. The charge collision regions are indicated by the dashed line. The simulated transmission spectra of the SSR and SRR array: (c) for parallel polarization and (d) for perpendicular polarization.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4048888&req=5

f1: S-shaped resonator (SSR) array.(a) Schematic and SEM image of the fabricated SSR metamaterial array. The unit cell has dimensions of w = 4 μm, l = 20 μm, and g = s = 12 μm. (b) Simulated surface current distributions of the SSR and SRR unit cells at ωf, ωh and ωc, respectively. The charge collision regions are indicated by the dashed line. The simulated transmission spectra of the SSR and SRR array: (c) for parallel polarization and (d) for perpendicular polarization.

Mentions: First, we fabricated the S-shaped resonators (SSRs) array having a negative refractive index39, and compared its resonance properties with the conventional SRR array. As shown in Figure 1a, the unit cell of the SSR structure consists of a pair of SRR structures, and it has a width (w) of 4 μm and length (l) of 20 μm with the gap (g) and space (s) both set to 12 μm. To analyze the actual metamaterial properties within the substrate, a 6-μm-thick polyimide substrate with assumed permittivity of 2.6 was considered for simulation. Figure 1b shows the surface current distributions of the SSR and SRR unit cells for each resonance frequency. In the SRR structure, resonances can be estimated by the different orders of standing waves and have odd symmetry for parallel polarization, whereas they have even symmetry for perpendicular polarization133738. However, in the SSR structure as shown in Figure 1b, the resonances for the perpendicular polarization do not have even symmetry due to the structural difference. In addition, the higher order resonance (ωh) for parallel polarization starts directly from the fifth order, skipping the third order resonance in the SRR structure. These results confirm that the resonance mechanism based on the odd and the even symmetry is valid only for the conventional SRR structure, but cannot be applied to SRR meta-atom clusters including the SSR structure.


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

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

S-shaped resonator (SSR) array.(a) Schematic and SEM image of the fabricated SSR metamaterial array. The unit cell has dimensions of w = 4 μm, l = 20 μm, and g = s = 12 μm. (b) Simulated surface current distributions of the SSR and SRR unit cells at ωf, ωh and ωc, respectively. The charge collision regions are indicated by the dashed line. The simulated transmission spectra of the SSR and SRR array: (c) for parallel polarization and (d) for perpendicular polarization.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f1: S-shaped resonator (SSR) array.(a) Schematic and SEM image of the fabricated SSR metamaterial array. The unit cell has dimensions of w = 4 μm, l = 20 μm, and g = s = 12 μm. (b) Simulated surface current distributions of the SSR and SRR unit cells at ωf, ωh and ωc, respectively. The charge collision regions are indicated by the dashed line. The simulated transmission spectra of the SSR and SRR array: (c) for parallel polarization and (d) for perpendicular polarization.
Mentions: First, we fabricated the S-shaped resonators (SSRs) array having a negative refractive index39, and compared its resonance properties with the conventional SRR array. As shown in Figure 1a, the unit cell of the SSR structure consists of a pair of SRR structures, and it has a width (w) of 4 μm and length (l) of 20 μm with the gap (g) and space (s) both set to 12 μm. To analyze the actual metamaterial properties within the substrate, a 6-μm-thick polyimide substrate with assumed permittivity of 2.6 was considered for simulation. Figure 1b shows the surface current distributions of the SSR and SRR unit cells for each resonance frequency. In the SRR structure, resonances can be estimated by the different orders of standing waves and have odd symmetry for parallel polarization, whereas they have even symmetry for perpendicular polarization133738. However, in the SSR structure as shown in Figure 1b, the resonances for the perpendicular polarization do not have even symmetry due to the structural difference. In addition, the higher order resonance (ωh) for parallel polarization starts directly from the fifth order, skipping the third order resonance in the SRR structure. These results confirm that the resonance mechanism based on the odd and the even symmetry is valid only for the conventional SRR structure, but cannot be applied to SRR meta-atom clusters including the SSR structure.

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