Tunable graphene-based infrared reflectance filter having patterned nanoantenna layer and unpatterned graphene layer

Patent metadata

Field	Value
Publication number	US-10877194-B2
Application number	US-201815872293-A
Country	US
Kind code	B2
Filing date	Jan 16, 2018
Priority date	Jan 16, 2018
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

An actively tunable optical filter can control the amplitude of reflected infrared light. The filter exploits the dependence of the excitation energy of plasmons in a continuous and unpatterned sheet of graphene, on the Fermi-level, which can be controlled by conventional electrostatic gating. An exemplary filter enables simultaneous modification of two distinct spectral bands whose positions are dictated by the device geometry and graphene plasmon dispersion. Within these bands, the reflected amplitude can be varied by over 15% and resonance positions can be shifted by over 90 cm −1 . Electromagnetic simulations verify that tuning arises through coupling of incident light to graphene plasmons by a nanoantenna grating structure. Importantly, the tunable range is determined by a combination of graphene properties, device structure, and the surrounding dielectrics, which dictate the plasmon dispersion. Thus, the underlying design is applicable across a broad range of infrared frequencies.

First claim

We claim:

1. A tunable graphene-based infrared reflectance filter, comprising:
a substrate;
a bottom dielectric layer on the substrate;
an unpatterned graphene layer on the bottom dielectric layer;
a top dielectric layer on the graphene layer; and
a conductive nanoantenna layer on the top dielectric layer, wherein the conductive nanoantenna layer is patterned to excite plasmons within the graphene layer and wherein the conductive nanoantenna layer is adapted to apply a voltage bias to the graphene layer, thereby changing the Fermi level of the graphene and tuning the resonance response of the infrared reflectance filter to infrared light incident on the top surface of the conductive nanoantenna layer.

2. The tunable graphene-based infrared reflectance filter of claim 1 , wherein the substrate comprises a conductive substrate, thereby providing a backgate.

3. The tunable graphene-based infrared reflectance filter of claim 2 , wherein the conductive substrate comprises degenerately doped silicon or a metal.

4. The tunable graphene-based infrared reflectance filter of claim 1 , wherein the substrate comprises an insulating substrate.

5. The tunable graphene-based infrared reflectance filter of claim 1 , wherein the bottom dielectric layer comprises silicon dioxide.

6. The tunable graphene-based infrared reflectance filter of claim 1 , wherein the bottom dielectric layer comprises hafnium dioxide, magnesium oxide, lead zirconium titanate, or alumina.

7. The tunable graphene-based infrared reflectance filter of claim 1 , wherein the top dielectric layer comprises hafnium dioxide.

8. The tunable graphene-based infrared reflectance filter of claim 1 , wherein the top dielectric layer comprises silicon dioxide, magnesium oxide, lead zirconium titanate, or alumina.

9. The tunable graphene-based infrared reflectance filter of claim 1 , wherein the nanoantenna comprises a grating having a periodicity comparable to the wavelength of the incident infrared light.

10. The tunable graphene-based infrared reflectance filter of claim 1 , wherein the nanoantenna comprises a metal.

11. The tunable graphene-based infrared reflectance filter of claim 1 , wherein the nanoantenna comprises a conductive oxide, polymer, or other conductive non-metal.

12. The tunable graphene-based infrared reflectance filter of claim 1 , wherein the wavelength of the incident infrared light is between 1 microns and 50 microns.

13. A tunable graphene-based infrared reflectance filter, comprising:
a conductive substrate;
a bottom dielectric layer on the substrate;
an unpatterned graphene layer on the bottom dielectric layer;
a top dielectric layer on the graphene layer; and
a nanoantenna layer on the top dielectric layer, wherein the nanoantenna layer is patterned to excite plasmons within the graphene layer; and
wherein the conductive substrate is adapted to apply a voltage bias to the graphene layer, thereby changing the Fermi level of the graphene and tuning the resonance response of the infrared reflectance filter to incidcnt infrared light incident on the top surface of the nanoantenna layer.

14. The tunable graphene-based infrared reflectance filter of claim 13 , wherein the nanoantenna layer comprises a conductive nanoantenna adapted to apply a bias voltage to the graphene layer, thereby providing a dual-gated infrared reflectance filter.

15. The tunable graphene-based infrared reflectance filter of claim 14 , wherein the conductive nanoantenna comprises a metal.

16. The tunable graphene-based infrared reflectance filter of claim 14 , wherein the conductive nanoantenna comprises a conductive oxide, polymer, or other conductive non-metal.

17. The tunable graphene-based infrared reflectance filter of claim 13 , wherein the nanoantenna layer comprises a grating having a periodicity comparable to the wavelength of the incident infrared light.

18. The tunable graphene-based infrared reflectance filter of claim 13 , wherein the bottom dielectric layer comprises silicon dioxide.

19. The tunable graphene-based infrared reflectance filter of claim 13 , wherein the bottom dielectric layer comprises hafnium dioxide, magnesium oxide, lead zirconium titanate, or alumina.

20. The tunable graphene-based infrared reflectance filter of claim 13 , wherein the top dielectric layer comprises hafnium dioxide.

21. The tunable graphene-based infrared reflectance filter of claim 13 , wherein the top dielectric layer comprises silicon dioxide, magnesium oxide, lead zirconium titanate, or alumina.

22. The tunable graphene-based infrared reflectance filter of claim 13 , wherein the wavelength of the incident infrared light is between 1 microns and 50 microns.

23. The tunable graphene-based infrared reflectance filter of claim 9 , wherein the periodicity is subwavelength to the incident infrared light.

24. The tunable graphene-based infrared reflectance filter of claim 17 , wherein the periodicity is subwavelength to the incident infrared light.

Assignees

• Nat Tech & Eng Solutions Sandia Llc

Inventors

• Beechem Iii Thomas Edwin
• Goldflam Michael
• Howell Stephen W
• Peters David W
• Ruiz Isaac
• Davids Paul

Classifications

• G02B5/008 Primary

  Surface plasmon devices (diffractive gratings with a pitch less than or comparable to the wavelength G02B5/1809; surface plasmons in integrated optics G02B6/1226; optical analysis of materials by means of surface plasmons G01N21/553) · CPC title

• G02F2203/10

  plasmon · CPC title

• G02B5/26

  Reflecting filters (G02B5/28 takes precedence) · CPC title

• G02B1/04

  made of organic materials, e.g. plastics (G02B1/08 takes precedence) · CPC title

• G01N21/553

  and using surface plasmons (fluorescence excitation G01N21/648; enhanced Raman G01N21/658) · CPC title