Spectral conversion element for electromagnetic radiation

Patent metadata

Field	Value
Publication number	US-10612979-B2
Application number	US-201816001166-A
Country	US
Kind code	B2
Filing date	Jun 6, 2018
Priority date	Jun 6, 2017
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

A spectral conversion element for electromagnetic radiation includes Terahertz antennas and infrared antennas which are distributed in pixel zones. The Terahertz antennas and the infrared antennas which are in one same pixel zone are thermally coupled, and those which are in different pixel zones are uncoupled. Such an element enables the capture of images which are formed with Terahertz radiation, by using an infrared image detector.

First claim

The invention claimed is:

1. Spectral conversion element ( 10 ) for electromagnetic radiation, comprising:
a two-dimensional support ( 1 ), with juxtaposed zones (ZP) which are respectively dedicated to pixels;
a set of first antennas ( 2 ), called Terahertz antennas, which are rigidly supported by the two-dimensional support ( 1 ) and sized to have a first absorption peak (P 1 ) for the electromagnetic radiation when a wavelength of the radiation is between 30 μm and 3 mm, corresponding to radiation referred to as Terahertz, at least one of the Terahertz antennas being situated inside each pixel zone (ZP); and
a set of second antennas ( 3 ), called infrared antennas, which are also rigidly supported by the two-dimensional support ( 1 ) but sized to have a second absorption peak (P 2 ) for the electromagnetic radiation when the wavelength of the radiation is between 1 μm and 30 μm, corresponding to radiation referred to as infrared, at least one of the infrared antennas being situated inside each pixel zone (ZP);

the conversion element being arranged so that one of the Terahertz antennas ( 2 ) and one of the infrared antennas ( 3 ) which are both situated in one same pixel zone (ZP), whatever said pixel zone, are thermally coupled with each other, with a thermal resistance which is lower than each other thermal resistance which exists between any one of the Terahertz antennas and any one of the infrared antennas when said Terahertz and infrared antennas are situated in the respective pixel zones which are different.

2. Conversion element ( 10 ) according to claim 1 , arranged so that each thermal resistance between one Terahertz antenna ( 2 ) and one infrared antenna ( 3 ) which are both situated in one same pixel zone (ZP), whatever said pixel zone, are lower than one tenth of each other thermal resistance which exists between any one of the Terahertz antennas and any one of the infrared antennas when said Terahertz and infrared antennas are situated in the respective pixel zones which are different.

3. The conversion element ( 10 ) according to claim 2 , wherein each thermal resistance between said one Terahertz antenna ( 2 ) and said one infrared antenna ( 3 ) which are both situated in one same pixel zone (ZP), whatever said pixel zone, are lower than one hundredth, of each other thermal resistance which exists between any one of the Terahertz antennas and any one of the infrared antennas when said Terahertz and infrared antennas are situated in the respective pixel zones which are different.

4. Conversion element ( 10 ) according to claim 2 , wherein each Terahertz antenna ( 2 ) or infrared antenna ( 3 ) is of metal/dielectric/metal type, or is of Helmholtz resonator type, or is formed by a portion of a material which is absorbing for infrared radiation or Terahertz radiation, respectively.

5. Conversion element ( 10 ) according to claim 2 , wherein each pixel zone (ZP) has transverse dimensions which are between 30 μm and 5000 μm, each Terahertz antenna ( 2 ) has a transverse dimension which is between 1 μm and 300 μm, and each infrared antenna ( 3 ) has a transverse dimension which is between 0.1 μm and 5 μm, said transverse dimensions being measured parallel to the two-dimensional support ( 1 ).

6. Conversion element ( 10 ) according to claim 2 , wherein the two-dimensional support ( 1 ) has connecting portions ( 4 ) to connect any two pixel zones (ZP) which are close to each other, and has recesses ( 5 ) which transversally limit each connecting portion, so that all the pixel zones are connected in said two-dimensional support, and that thermal diffusion passages between two pixel zones which are close to each other have sections limited by some of the recesses.

7. Conversion element ( 10 ) according to claim 1 , wherein each Terahertz antenna ( 2 ) or infrared antenna ( 3 ) is of metal/dielectric/metal type, or is of Helmholtz resonator type, or is formed by a portion of a material which is absorbing for infrared radiation or Terahertz radiation, respectively.

8. Conversion element ( 10 ) according to claim 7 , wherein each pixel zone (ZP) has transverse dimensions which are between 30 μm and 5000 μm, each Terahertz antenna ( 2 ) has a transverse dimension which is between 1 μm and 300 μm, and each infrared antenna ( 3 ) has a transverse dimension which is between 0.1 μm and 5 μm, said transverse dimensions being measured parallel to the two-dimensional support ( 1 ).

9. Conversion element ( 10 ) according to claim 7 , wherein the two-dimensional support ( 1 ) has connecting portions ( 4 ) to connect any two pixel zones (ZP) which are close to each other, and has recesses ( 5 ) which transversally limit each connecting portion, so that all the pixel zones are connected in said two-dimensional support, and that thermal diffusion passages between two pixel zones which are close to each other have sections limited by some of the recesses.

10. Conversion element ( 10 ) according to claim 1 , wherein each pixel zone (ZP) has transverse dimensions which are between 30 μm and 5000 μm, each Terahertz antenna ( 2 ) has a transverse dimension which is between 1 μm and 300 μm, and each infrared antenna ( 3 ) has a transverse dimension which is between 0.1 μm and 5 μm, said transverse dimensions being measured parallel to the two-dimensional support ( 1 ).

11. Conversion element ( 10 ) according to claim 10 , wherein the two-dimensional support ( 1 ) has connecting portions ( 4 ) to connect any two pixel zones (ZP) which are close to each other, and has recesses ( 5 ) which transversally limit each connecting portion, so that all the pixel zones are connected in said two-dimensional support, and that thermal diffusion passages between two pixel zones which are close to each other have sections limited by some of the recesses.

12. Conversion element ( 10 ) according to claim 1 , wherein the two-dimensional support ( 1 ) has connecting portions ( 4 ) to connect any two pixel zones (ZP) which are close to each other, and has recesses ( 5 ) which transversally limit each connecting portion, so that all the pixel zones are connected in said two-dimensional support, and that thermal diffusion passages between two pixel zones which are close to each other have sections limited by some of the recesses.

13. Conversion element ( 10 ) according to claim 1 , wherein each Terahertz antenna ( 2 ) has a geometry which is selected among several different geometries, said Terahertz antenna geometries corresponding to different polarisations or different wavelengths for the electromagnetic radiation which is absorbed with a maximum effectiveness,
and wherein each pixel zone (ZP) comprises at least one of said Terahertz antenna geometries ( 2 ), and the Terahertz antenna geometries are alternated between pixel zones which are different.

14. Conversion element ( 10 ) according to claim 13 , wherein each pixel zone (ZP) comprises one single antenna geometry.

15. Conversion element ( 10 ) according to claim 14 , wherein the Terahertz antenna geometries are alternated between pixel zones which are different, according to an alternating pattern which is identical in the whole conversion element ( 10 ).

16. Conversion element ( 10 ) according to claim 1 , wherein both the Terahertz antennas ( 2 ) and the infrared antennas ( 3 ) are supported by two opposing faces of the two-dimensional support ( 1 ), the thermal resistances being produced along thermal diffusion paths which cross the two-dimensional support between the two opposing faces.

17. Conversion element ( 10 ) according to claim 1 , wherein the Terahe

Assignees

• Office National Detudes Rech Aerospatiales

Inventors

• Bouchon Patrick
• Haidar Riad
• Makhsiyan Mathilde

Classifications

• H01Q17/004

  using non-directional dissipative particles, e.g. ferrite powders (H01Q17/005 takes precedence; flake-like H01Q17/002) · CPC title

• G02F2/02 Primary

  Frequency-changing of light, e.g. by quantum counters · CPC title

• G02F2203/13

  involving THZ radiation · CPC title

• H01Q17/00

  Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems · CPC title

• H01Q1/523

  between antennas of an array · CPC title