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

摘要

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 μm, as well as high emissivity up to 0.65 at a wavelength of 3.7 μm. 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.

主权项

1. A polarized thermal emitter (PTE) for use in a thermophotovoltaic (TPV) device, comprising:
a backplane; a first grating layer positioned on the backplane; a second grating layer positioned on the first grating layer and oriented substantially perpendicular to the first grating layer; and wherein one of the first grating layer and the second grating layer has a sub-wavelength periodicity, wherein sub-wavelength periodicity is a periodicity less than 2.5 μm.