Current Search: Plasmonics -- infrared -- far-infrared -- THz -- absorber (x)
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Title
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Far-infrared bands in plasmonic metal-insulator-metal absorbers optimized for long wave infrared.
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Creator
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Evans, Rachel, Peale, Robert, Ishigami, Masahiro, Lyakh, Arkadiy, University of Central Florida
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Abstract / Description
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Metal(-)insulator(-)metal (MIM) resonant absorbers comprise a conducting ground plane, a thin dielectric, and thin separated metal top-surface structures. Long-wave infrared (LWIR) fundamental absorptions are experimentally shown to be optimized for a ratio of dielectric thickness to top-structure dimension t/l (>) 0.08. The fundamental resonance wavelength is predicted by different analytic standing-wave theories to be ~2nl, where n is the dielectric refractive index. Thus, for the...
Show moreMetal(-)insulator(-)metal (MIM) resonant absorbers comprise a conducting ground plane, a thin dielectric, and thin separated metal top-surface structures. Long-wave infrared (LWIR) fundamental absorptions are experimentally shown to be optimized for a ratio of dielectric thickness to top-structure dimension t/l (>) 0.08. The fundamental resonance wavelength is predicted by different analytic standing-wave theories to be ~2nl, where n is the dielectric refractive index. Thus, for the dielectrics SiO2, AlN, and TiO2, l values of a few microns give fundamentals in the 8-12 micron LWIR wavelength region. Agreement of observed fundamental resonance wavelength with theory is better for t/l (>) ~0.2. Harmonics at shorter wavelengths are always observed, but we show that there are additional resonances in the far-infrared 20-50 micron wavelength range, well beyond the predicted fundamental. These appear to be due to dispersion. They may impact selectivity in spectral sensing applications.
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Date Issued
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2018
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Identifier
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CFE0007176, ucf:52267
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Format
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Document (PDF)
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PURL
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http://purl.flvc.org/ucf/fd/CFE0007176