Polarized thermal radiation by layer-by-layer metallic emitters with sub-wavelength grating.
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 mum, as well as high emissivity up to 0.65 at a wavelength of 3.7 microm. 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
JH
Ames Laboratory U.S .DOE, Iowa State University, Ames, IA, 50011, USA. leejh@iastate.edu
Leung
Wai
W
Kim
Tae Guen
TG
Constant
Kristen
K
Ho
Kai-Ming
KM
D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006358:Hot Temperature; D008027:Light; D008670:Metals / Q000737:chemistry*; D008962:Models, Theoretical; D055095:Optics and Photonics / Q000295:instrumentation*; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation
D008670:Metals