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Metallic layer-by-layer photonic crystals for linearly-polarized thermal emission and thermophotovoltaic device including same

United States Patent

July 26, 2016
View the Complete Patent at the US Patent & Trademark Office
Metallic thermal emitters consisting of two layers of differently structured nickel gratings on a homogeneous nickel layer are fabricated by soft lithography and studied for polarized thermal radiation. A thermal emitter in combination with a sub-wavelength grating shows a high extinction ratio, with a maximum value close to 5, in a wide mid-infrared range from 3.2 to 7.8 .mu.m, as well as high emissivity up to 0.65 at a wavelength of 3.7 .mu.m. All measurements show good agreement with theoretical predictions. Numerical simulations reveal that a high electric field exists within the localized air space surrounded by the gratings and the intensified electric-field is only observed for the polarizations perpendicular to the top sub-wavelength grating. This result suggests how the emissivity of a metal can be selectively enhanced at a certain range of wavelengths for a given polarization.
Lee; Jae-Hwang (Chestnut Hill, MA), Ho; Kai-Ming (Ames, IA), Constant; Kristen P. (Ames, IA)
Iowa State University Research Foundation, Inc. (Ames, IA)
12/ 754,657
April 6, 2010
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT This invention was made in part with Government support under Grant Number DE-ACO2-06CH11358 awarded by the Department of Energy. The Government has certain rights in this invention.