Closed-form formulae of effective parameters of hyperbolic metamaterial made by stacked hole-array layers working at terahertz or microwave radiation
| Autor: | Masatsugu Yamashita, Chesta Ruttanapun, Piyawath Tapsanit, Chiko Otani, Sriprajak Krongsuk |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
business.industry Terahertz radiation Superlattice Physics::Optics Metamaterial Statistical and Nonlinear Physics 02 engineering and technology Physics::Classical Physics 021001 nanoscience & nanotechnology Plasma oscillation 01 natural sciences Atomic and Molecular Physics and Optics Wavelength Optics Dispersion relation 0103 physical sciences Metamaterial absorber Optoelectronics 010306 general physics 0210 nano-technology business Microwave |
| Zdroj: | Journal of the Optical Society of America B. 34:1930 |
| ISSN: | 1520-8540 0740-3224 |
| DOI: | 10.1364/josab.34.001930 |
| Popis: | A metamaterial made by stacked hole-array layers, known as a fishnet metamaterial, behaves as a hyperbolic metamaterial at a wavelength much longer than the hole-array period. However, the analytical formulae of the effective parameters of a fishnet metamaterial have not been reported, hindering the design of deep-subwavelength imaging devices using this structure. We report the new closed-form formulae of effective parameters comprising the anisotropic dispersion relation of a fishnet metamaterial working at terahertz or microwave frequency. These effective parameters of a fishnet metamaterial are consistent with those obtained by quasi-full solutions using known effective parameters of a hole-array layer working at a frequency below its spoof plasma frequency with the superlattice period much smaller than the hole-array period. We also theoretically demonstrate deep-subwavelength focusing at λ/83 using a composite structure of a slit-array layer and a fishnet metamaterial. It is found that the focused intensity inside a fishnet metamaterial is several times larger than that without the fishnet metamaterial, but the transmitted intensity is still restricted by a large-wavevector difference in air and a fishnet metamaterial. Our effective parameters may aid next-generation deep-subwavelength imaging devices working under terahertz or microwave radiation. |
| Databáze: | OpenAIRE |
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