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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

Experimental results of combined complementary SRR metamaterial array.(a) Optical microscopy images of the fabricated complementary SSR metamaterials with different numbers (n) of combined complementary SRR unit cells. Measured and simulated transmission spectra of the complementary SSR metamaterials (b) for parallel polarization and (c) for perpendicular polarization. The higher order frequency components are considered as spectral noise shown as shaded areas in each figure.
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f4: Experimental results of combined complementary SRR metamaterial array.(a) Optical microscopy images of the fabricated complementary SSR metamaterials with different numbers (n) of combined complementary SRR unit cells. Measured and simulated transmission spectra of the complementary SSR metamaterials (b) for parallel polarization and (c) for perpendicular polarization. The higher order frequency components are considered as spectral noise shown as shaded areas in each figure.

Mentions: In order to verify the anisotropic resonant responses further, the proposed SSR metamaterials were fabricated by using the conventional photo-lithography technique. Figures 3a shows the fabricated anisotropic SSR metamaterials. The detailed fabrication process is described in the Methods section. Figure 3b and c shows the measured transmission spectra for the SSR metamaterials in comparison with the simulated results. As shown in the figures, when the number of SRR cells increases from 1 to 4, the measured resonance frequency changes from 2.0, 1.45, 1.25, to 1.05 THz, respectively. On the other hand, for the perpendicular polarization, the resonance frequency of all SSR arrays stays near 5.1 THz with only small variations of less than 2%. Therefore, we confirm that the proposed anisotropic meta-atoms altered the resonance frequency for parallel polarization, and had a fixed resonance frequency for perpendicular polarization. Figure 3 also shows that the measured results well matched the simulation results. A slight discrepancy in the resonance between the simulated and the measured results is due to the variations in the fabrication process of the structure. Interestingly, the complementary structures showed exactly the same tendency with respect to the SSR metamaterials due to the Babinet principle, as shown in Figure 4354142. Since the complementary structure has the opposite properties to the original structure, the proposed design methods can be utilized not only for the reflective, but also for the transmissive metamaterial array filters.


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

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

Experimental results of combined complementary SRR metamaterial array.(a) Optical microscopy images of the fabricated complementary SSR metamaterials with different numbers (n) of combined complementary SRR unit cells. Measured and simulated transmission spectra of the complementary SSR metamaterials (b) for parallel polarization and (c) for perpendicular polarization. The higher order frequency components are considered as spectral noise shown as shaded areas in each figure.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4: Experimental results of combined complementary SRR metamaterial array.(a) Optical microscopy images of the fabricated complementary SSR metamaterials with different numbers (n) of combined complementary SRR unit cells. Measured and simulated transmission spectra of the complementary SSR metamaterials (b) for parallel polarization and (c) for perpendicular polarization. The higher order frequency components are considered as spectral noise shown as shaded areas in each figure.
Mentions: In order to verify the anisotropic resonant responses further, the proposed SSR metamaterials were fabricated by using the conventional photo-lithography technique. Figures 3a shows the fabricated anisotropic SSR metamaterials. The detailed fabrication process is described in the Methods section. Figure 3b and c shows the measured transmission spectra for the SSR metamaterials in comparison with the simulated results. As shown in the figures, when the number of SRR cells increases from 1 to 4, the measured resonance frequency changes from 2.0, 1.45, 1.25, to 1.05 THz, respectively. On the other hand, for the perpendicular polarization, the resonance frequency of all SSR arrays stays near 5.1 THz with only small variations of less than 2%. Therefore, we confirm that the proposed anisotropic meta-atoms altered the resonance frequency for parallel polarization, and had a fixed resonance frequency for perpendicular polarization. Figure 3 also shows that the measured results well matched the simulation results. A slight discrepancy in the resonance between the simulated and the measured results is due to the variations in the fabrication process of the structure. Interestingly, the complementary structures showed exactly the same tendency with respect to the SSR metamaterials due to the Babinet principle, as shown in Figure 4354142. Since the complementary structure has the opposite properties to the original structure, the proposed design methods can be utilized not only for the reflective, but also for the transmissive metamaterial array filters.

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