Far-infrared bands in plasmonic metal-insulator-metal absorbers optimized for long-wave infrared
| Autor: | Jonathan R. Brescia, Justin W. Cleary, Seth Calhoun, Rachel N. Evans, Robert E. Peale, Evan M. Smith |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Infrared business.industry Mechanical Engineering Physics::Optics 02 engineering and technology Dielectric 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Condensed Matter::Materials Science Wavelength Far infrared Mechanics of Materials Dispersion (optics) Optoelectronics General Materials Science 0210 nano-technology business Refractive index Plasmon Ground plane |
| Zdroj: | MRS Advances. 4:667-674 |
| ISSN: | 2059-8521 |
| Popis: | Metal–insulator–metal (MIM) resonant absorbers comprise a conducting ground plane, a dielectric of thickness t, and thin separated metal top-surface structures of dimension l. The fundamental resonance wavelength is predicted by an analytic standing-wave model based on t, l, and the dielectric refractive index spectrum. For the dielectrics SiO2, AlN, and TiO2, values for l of a few microns give fundamental resonances in the 8-12 μm long-wave infrared (LWIR) wavelength region. Agreement with theory is better for t/l exceeding 0.1. Harmonics at shorter wavelengths were already known, but we show that there are additional resonances in the far-infrared 20 - 50 μm wavelength range in MIM structures designed to have LWIR fundamental resonances. These new resonances are consistent with the model if far-IR dispersion features in the index spectrum are considered. LWIR fundamental absorptions are experimentally shown to be optimized for a ratio t/l of 0.1 to 0.3 for SiO2- and AlN-based MIM absorbers, respectively, with TiO2-based MIM optimized at an intermediate ratio. |
| Databáze: | OpenAIRE |
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