Nano-antenna array infrared imager

Patent metadata

Field	Value
Publication number	US-9813644-B1
Application number	US-201514744779-A
Country	US
Kind code	B1
Filing date	Jun 19, 2015
Priority date	Jun 19, 2014
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

An infrared imager includes a first optical component, a second optical component, and at least one thin film dielectric layer. The first optical component has multiple first parallel conductors with a first spacing pattern, aligned in a plane perpendicular to an axis. The second optical component has multiple second parallel conductors with a second spacing pattern, aligned in a plane perpendicular to the axis, angularly offset from the first direction. The thin film dielectric layer includes a refractive index change (RIC) material disposed between and in contact with the first and second parallel conductors. The first optical component, second optical component, and at least one thin film dielectric layer form an antenna array configured to detect one or more predetermined infrared wavelengths based on at least one of the first spacing pattern or the second spacing pattern or the angular offset.

First claim

We claim:

1. An apparatus comprising:
a first optical component having a plurality of first parallel conductors with a first spacing pattern, the plurality of first parallel conductors aligned in a plane perpendicular to an axis;
a second optical component having a plurality of second parallel conductors with a second spacing pattern, the plurality of second parallel conductors aligned in a plane perpendicular to the axis; and
at least one thin film dielectric layer including a refractive index change (RIC) material disposed between and in contact with the plurality of first parallel conductors and the plurality of second parallel conductors,
wherein the second spacing pattern is angularly offset from the first spacing pattern by an angular offset, and
the first optical component and the second optical component and the at least one thin film dielectric layer form an antenna array configured to detect one or more predetermined infrared wavelengths based on at least one of the first spacing pattern and the second spacing pattern and the angular offset.

2. The apparatus of claim 1 , wherein at least one of the first spacing pattern or the second spacing pattern is selected from one of: a constant spacing pattern; a gradient spacing pattern; or a combination of the constant spacing pattern and the gradient spacing pattern.

3. The apparatus of claim 1 , wherein the first spacing pattern comprises a plurality of spacing patterns wherein: each pattern of the plurality of spacing patterns is associated with an area on the first optical component; and, each pattern of the plurality of spacing patterns has at least one of a different repeat distance or different conductor width.

4. The apparatus of claim 1 , wherein the second spacing pattern comprises a plurality of spacing patterns wherein: each pattern of the plurality of spacing patterns is associated with an area on the second optical component; and, each pattern of the plurality of spacing patterns has at least one of a different repeat distance or different conductor width.

5. The apparatus of claim 1 , wherein the angular offset is adjustable to tune the antenna array to the one or more predetermined infrared wavelengths.

6. The apparatus of claim 1 , wherein the one or more predetermined infrared wavelengths are in a mid-wave infrared (MWIR) wavelength band.

7. The apparatus of claim 1 , wherein the first optical component comprises a first substrate layer that is transmissive at the one or more predetermined infrared wavelengths.

8. The apparatus of claim 7 , wherein the second optical component comprises a second substrate layer that is transmissive at the one or more predetermined infrared wavelengths.

9. The apparatus of claim 8 , wherein the first substrate and the second substrate comprise the same material.

10. The apparatus of claim 9 , wherein the first substrate and the second substrate comprise sapphire.

11. The apparatus of claim 1 , wherein the thin film dielectric layer has a thickness of less than about one quarter of each of the one or more predetermined infrared wavelengths.

12. The apparatus of claim 1 , wherein the angular offset is in a range from greater than zero degrees to about 90 degrees.

13. The apparatus of claim 1 , wherein the plurality of first parallel conductors and the plurality of second parallel conductors are both transparent at an optical wavelength used for probing the apparatus.

14. The apparatus of claim 13 , wherein the conductors of the plurality of first conductors and the plurality of second conductors comprise a material selected from a group comprising indium tin oxide (ITO) and graphene.

15. The apparatus of claim 1 , wherein:
the thin film dielectric layer comprises vanadium dioxide (VO 2 );
the VO 2 heats in response to a voltage difference induced across the thin film dielectric layer at each antenna of the antenna array; and
above a temperature near 68 degrees Celsius, the crystalline structure of the VO 2 changes which cause a complex index of refraction of the RIC material to change.

16. The apparatus of claim 15 , further comprising a heater or a cooler configured to keep the temperature of the thin film dielectric layer near 68 degrees Celsius.

17. The apparatus of claim 1 , wherein:
the thin film dielectric layer comprises lithium niobate (LiNbO 3 ); and
the complex index of refraction is based on a voltage difference induced across the thin film dielectric layer at each antenna of the antenna array.

18. A system comprising:
the apparatus of claim 1 ;
a source of probe light at an optical wavelength affected by a change in the RIC material;
an optical coupler configured to direct the probe light onto the apparatus of claim 1 ; and
an array of optical detectors configured to detect probe light transmitted through or reflected by the apparatus of claim 1 .

19. The system of claim 18 , further comprising an amplifier disposed between the apparatus of claim 1 and the array of optical detectors, wherein the amplifier is configured to amplify differences between probe light interacting with the RIC material in different phases induced by infrared radiation at the one or more predetermined infrared wavelengths.

20. The system of claim 19 , wherein:
the RIC material comprises LiNbO 3 ; and
the amplifier is a polarization magnifier.

Assignees

• Lockheed Corp

Inventors

• Jackson Paul E
• Baleine Clara R
• Voita Christopher P

Classifications

• G01J1/0448 Primary

  Adjustable, e.g. focussing · CPC title

• G01J2001/448

  Array [CCD] · CPC title

• G01J2005/0077

  Imaging · CPC title

• G01J5/0896

  using a light source, e.g. for illuminating a surface · CPC title

• G01J1/4228

  arrangements with two or more detectors, e.g. for sensitivity compensation · CPC title