| FUNDAMENTAL AREAS OF PHENOMENOLOGY(INCLUDING APPLICATIONS) |
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Multi-Band Absorption Properties and Near-Field Enhancement in Mid-Infrared Based on the Interference Theory |
| HENG Hang1,2**, YANG Li1 |
1Department of Physics, Nanjing Normal University, Nanjing 210097
2Center for Analysis and Testing, Nanjing Normal University, Nanjing 210097
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| Cite this article: |
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HENG Hang, YANG Li 2014 Chin. Phys. Lett. 31 054201 |
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Abstract We numerically study the multi-band absorption properties and near-field enhancement inside the microcavity based on the interference theory. The compact single unit cell consists of a gold square patch placed on the top of a metallic ground plane, separated by a dielectric layer. At the normal incidence of electromagnetic radiation, four bands of a maximum absorption of 98% are accomplished by appropriate sizes of the square patch. Furthermore, we demonstrate that the four bands, which are corresponding to the fundamental mode and higher modes of the standing wave, can be readily tuned in the mid-infrared region and associated with the near-field enhancement in the cuboid microcavity. Since chemical and biological fingerprints of the common functional groups can be found in the mid-infrared region, we may readily tune the multi-bands of interest in the mid-infrared range and identify the molecular stretches of groups. Moreover, the proposed structure is insensitive to the polarization of the incident wave due to the complete rotational symmetry (C4 symmetry). The unique properties of the optical metamaterial indicate that this approach is a promising strategy for surface-enhanced infrared absorption spectroscopy and for the tracking of characteristic molecular vibrational modes
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Published: 24 April 2014
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| PACS: |
81.05.Xj
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(Metamaterials for chiral, bianisotropic and other complex media)
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42.55.Sa
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(Microcavity and microdisk lasers)
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25.40.Ny
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(Resonance reactions)
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43.20.Ks
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(Standing waves, resonance, normal modes)
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Abstract
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