Polarized thermal radiation by layer-by-layer metallic emitters with sub-wavelength grating

TitlePolarized thermal radiation by layer-by-layer metallic emitters with sub-wavelength grating
Publication TypeJournal Article
Year of Publication2008
AuthorsLee JH, Leung W, Kim TG, Constant K, Ho KM
Journal TitleOptics Express
Volume16
Pages8742-8747
Date PublishedJun
Type of ArticleArticle
ISBN Number1094-4087
Accession NumberISI:000256859900042
KeywordsDOPED SILICON, EMISSION, surfaces, temperature
Abstract

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. (c) 2008 Optical Society of America.

Alternate JournalOpt. Express