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

Patent metadata

Field	Value
Publication number	US-9400219-B2
Application number	US-75465710-A
Country	US
Kind code	B2
Filing date	Apr 6, 2010
Priority date	May 19, 2009
Publication date	Jul 26, 2016
Grant date	Jul 26, 2016

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 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.

First claim

What is claimed is:

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.

2. The PTE of claim 1 , wherein the first grating layer has a sub-wavelength periodicity.

3. The PTE of claim 1 , wherein the second grating layer has a sub-wavelength periodicity.

4. The PTE of claim 3 , wherein the first grating layer includes a first plurality of parallel rods approximately 1.1 μm wide and 1.2 μm high, with approximately 2.6 μm of rod-to-rod spacing, and wherein the second grating layer includes a second plurality of parallel rods approximately 0.6 μm wide and 0.4 μm high, with 1.0 μm of rod-to-rod spacing.

5. The PTE of claim 1 , wherein the first grating layer and the second grating layer have different periodicities.

6. A thermophotovoltaic (TPV) device, comprising:
a polarized thermal emitter (PTE) having a backplane, a first grating layer positioned on the backplane, a second grating layer positioned on the first grating layer and oriented 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; and
a photodiode positioned to receive thermal radiation (TR) from the PTE.

7. The TPV of claim 6 , wherein the first grating layer has a sub-wavelength periodicity.

8. The TPV of claim 6 , wherein the second grating layer has a sub-wavelength periodicity.

9. The TPV of claim 8 , wherein the first grating layer includes a first plurality of parallel rods approximately 1.1 μm wide and 1.2 μm high, with approximately 2.6 μm of rod-to-rod spacing, and wherein the second grating layer includes a second plurality of parallel rods approximately 0.6 μm wide and 0.4 μm high, with 1.0 μm of rod-to-rod spacing.

10. The TPV of claim 6 , wherein the first grating layer and the second grating layer have different periodicities.

11. The TPV of claim 6 , wherein the first and second grating layers are configured such that the PTE has an extinction ratio greater than four.

12. The PTE of claim 1 , wherein the first and second grating layers are configured such that the PTE has an extinction ratio greater than four.

Assignees

• Lee Jae-Hwang
• Ho Kai-Ming
• Constant Kristen P
• Univ Iowa State Res Found Inc

Inventors

• Lee Jae-Hwang
• Ho Kai-Ming
• Constant Kristen P

Classifications

• G01J3/108 Primary

  for measurement in the infrared range · CPC title

• G01J5/522 Primary

  Physics · mapped topic

• H02S10/30

  Thermophotovoltaic systems (photovoltaic cells specially adapted for conversion or sensing of infrared [IR] radiation H10F10/00; thermoelectric devices H10N10/00) · CPC title

• G01J5/53 Primary

  Reference sources, e.g. standard lamps; Black bodies · CPC title

• Y02E10/50

  Photovoltaic [PV] energy · CPC title