Multilayer photonic structures

• US 8,593,728 B2
• Filed: 01/13/2010
• Issued: 11/26/2013
• Est. Priority Date: 02/19/2009
• Status: Active Grant

• Current Assignee: Toyota Motor Corporation
• Original Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation)
• Inventors: Banerjee, Debasish, Grayson, Benjamin Alan, Zhang, Minjuan, Ishil, Masahiko
• Primary Examiner(s): Chapel, Derek S
• Application Number:
  US12/686,861
• Publication Number:
  US 20100208338A1
• Time in Patent Office: 1,413 Days
• Field of Search: None
• US Class Current: 359/359
• CPC Class Codes: G02B 5/208 for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation
• CPC Class Codes: G02B 5/281 designed for the infrared light
• CPC Class Codes: G02B 5/283 designed for the ultraviolet
• CPC Class Codes: G02B 5/285 comprising deposited thin solid films G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361

Abstract

A multilayer photonic structure may include a plurality of coating layers of high index dielectric material of index of refraction n_H and a plurality of coating layers of low index dielectric material of index of refraction n_L alternately arranged with a first coating layer and a last coating layer of the multi-layer photonic structure comprise low index material. An index-thickness of each coating layer of the multilayer photonic structure is different than every other coating layer of the multilayer photonic structure. The multilayer photonic structure has a first high reflectivity bandwidth, a second high reflectivity bandwidth and a low reflectivity bandwidth wherein the low reflectivity bandwidth is positioned between the first high reflectivity bandwidth and the second high reflectivity bandwidth.

Claims

1. A multilayer photonic structure comprising a plurality of coating layers of high index dielectric material having an index of refraction n_H and a plurality of coating layers of low index dielectric material having an index of refraction n_L, wherein:

the plurality of coating layers of high index dielectric material and the plurality of coating layers of low index dielectric material are alternately arranged and a first coating layer and a last coating layer of the multilayer photonic structure comprise low index material;

an index-thickness of each coating layer of low index dielectric material is different than the index-thickness of each other coating layer of low index dielectric material;

an index-thickness of each coating layer of high index dielectric material is different than the index-thickness of each other coating layer of high index dielectric material;

the index-thickness of each coating layer of low index dielectric material is different than the index-thickness of each coating layer of high index dielectric material; and

the multilayer photonic structure has a first high reflectivity bandwidth, a second high reflectivity bandwidth and a low reflectivity bandwidth for electromagnetic radiation incident on a surface of the multilayer photonic structure in a range from 0 degrees to 45 degrees relative to a normal to the surface of the multilayer photonic structure, wherein the low reflectivity bandwidth is positioned between the first high reflectivity bandwidth and the second high reflectivity bandwidth.

2. The multilayer photonic structure of claim 1 wherein:

the first high reflectivity bandwidth has a reflectance of 50% or greater for wavelengths of electromagnetic radiation within the first high reflectivity bandwidth and incident on a surface of the multilayer photonic structure in a range from 0 degrees to 45 degrees relative to a normal to the surface of the multilayer photonic structure;

the low reflectivity bandwidth has a reflectance of less than 50% for wavelengths of electromagnetic radiation within the low reflectivity bandwidth and incident on a surface of the multilayer photonic structure in a range from 0 degrees to 45 degrees relative to a normal to the surface of the multilayer photonic structure; and

the second high reflectivity bandwidth has a reflectance of 50% or greater for wavelengths of electromagnetic radiation within the second high reflectivity bandwidth and incident on a surface of the multilayer photonic structure in a range from 0 degrees to 45 degrees relative to a normal to the surface of the multilayer photonic structure.

3. The multilayer photonic structure of claim 1 wherein:

the plurality of coating layers of high index material consists of four coating layers of high index dielectric material;

the first high reflectivity bandwidth comprises wavelengths of electro-magnetic radiation in an ultraviolet portion of the electromagnetic spectrum;

the low reflectivity bandwidth comprises wavelengths of electro-magnetic radiation in a visible portion of the electromagnetic spectrum; and

the second high reflectivity bandwidth comprises wavelengths of electro-magnetic radiation in an infrared portion of the electromagnetic spectrum.

4. The multilayer photonic structure of claim 1 wherein:

the first high reflectivity bandwidth has a reflectance of 50% or greater for wavelengths of electro-magnetic radiation less than about 400 nm;

the low reflectivity bandwidth has a reflectance of less than 20% for wavelengths of electro-magnetic radiation from about 400 nm to about 800 nm; and

the second high reflectivity bandwidth has a reflectance of greater than 80% for wavelengths of electro-magnetic radiation greater than about 800 nm.

5. The multilayer photonic structure of claim 1 wherein the index-thickness of each coating layer of the multilayer photonic structure is a non-quarter wave thickness.

6. The multilayer photonic structure of claim 1 wherein a thickness of each coating layer is from about 10 nm to about 400 nm.

7. The multilayer photonic structure of claim 1 wherein the index of refraction n_L is 1.46.

8. The multilayer photonic structure of claim 1 wherein the index of refraction n_H is 2.29.

9. The multilayer photonic structure of claim 1 wherein the high index dielectric material is TiO₂.

10. The multilayer photonic structure of claim 1 wherein the low index material is SiO₂.

11. A UV-IR reflector comprising a plurality of coating layers of high index dielectric material having an index of refraction n_H and a plurality of coating layers of low index dielectric material having an index of refraction n_L, wherein:

the plurality of coating layers of high index dielectric material and the plurality of coating layers of low index dielectric material are alternately arranged and a first coating layer and a last coating layer of the UV-IR reflector comprise low index material;

an index-thickness of each coating layer of low index dielectric material is different than the index-thickness of each other coating layer of low index dielectric material;

an index-thickness of each coating layer of high index dielectric material is different than the index-thickness of each other coating layer of high index dielectric material;

the index-thickness of each coating layer of low index dielectric material is different than the index-thickness of each coating layer of high index dielectric material; and

the UV-IR reflector has a first high reflectivity bandwidth with a reflectance of 50% or greater for wavelengths of electromagnetic radiation in an ultraviolet portion of the electromagnetic spectrum and a second high reflectivity bandwidth with a reflectance of 80% or greater for wavelengths of light in an infrared portion of the electromagnetic spectrum.

12. The UV-IR reflector of claim 11 wherein the first high reflectivity bandwidth includes electromagnetic radiation with a wavelength of about 400 nm or less and the second high reflectivity bandwidth includes electromagnetic radiation with a wavelength of about 800 nm or more.

13. The UV-IR reflector of claim 12 wherein electromagnetic radiation having wavelengths within the first high reflectivity bandwidth and the second high reflectivity bandwidth are omnidirectionally reflected for angles of incidence in a range from 0 degrees to 45 degrees relative to a normal to a surface of the UV-IR reflector.

14. The UV-IR reflector of claim 11 wherein:

the plurality of coating layers of high index material consists of four coating layers of high index material; and

the plurality of coating layers of low index material consists of five coating layers of low index material.

15. The UV-IR reflector of claim 14 wherein the index of refraction n_L is 1.46 and the index of refraction n_H is 2.29.

16. The UV-IR reflector of claim 15 wherein:

the five coating layers of low index material have respective thicknesses of 96.3018 nm, 182.3853 nm, 172.8356 nm, 172.9439 nm, and 86.19178 nm in order of deposition; and

the four coating layers of high index material have respective thicknesses of 122.7953 nm, 109.7658 nm, 110.6184 nm, and 109.9039 nm in order of deposition.

17. An article of manufacture comprising a multilayer photonic structure, the multilayer photonic structure comprising a plurality of coating layers of high index dielectric material having an index of refraction n_H and a plurality of coating layers of low index dielectric material having an index of refraction n_L, wherein:

the plurality of coating layers of high index dielectric material and the plurality of coating layers of low index dielectric material are alternately arranged and a first coating layer and a last coating layer of the multilayer photonic structure comprise low index material;

an index-thickness of each coating layer of low index dielectric material is different than the index-thickness of each other coating layer of low index dielectric material;

an index-thickness of each coating layer of high index dielectric material is different than the index-thickness of each other coating layer of high index dielectric material;

the index-thickness of each coating layer of low index dielectric material is different than the index-thickness of each coating layer of high index dielectric material; and

the multilayer photonic structure has a first high reflectivity bandwidth, a second high reflectivity bandwidth and a low reflectivity bandwidth for electromagnetic radiation incident on a surface of the multilayer photonic structure in a range from 0 degrees to 45 degrees relative to a normal to the surface of the multilayer photonic structure, wherein the low reflectivity bandwidth is positioned between the first high reflectivity bandwidth and the second high reflectivity bandwidth.

18. The article of manufacture of claim 17 wherein:

the first high reflectivity bandwidth has a reflectance of 50% or greater for wavelengths of electro-magnetic radiation less than about 400 nm bandwidth and incident on a surface of the multilayer photonic structure in a range from 0 degrees to 45 degrees relative to a normal to the surface of the multilayer photonic structure;

the low reflectivity bandwidth has a reflectance of less than 20% for wavelengths of electro-magnetic radiation from about 400 nm to about 800 nm bandwidth and incident on a surface of the multilayer photonic structure in a range from 0 degrees to 45 degrees relative to a normal to the surface of the multilayer photonic structure; and

the second high reflectivity bandwidth has a reflectance of greater than 80% for wavelengths of electro-magnetic radiation greater than about 800 nm bandwidth and incident on a surface of the multilayer photonic structure in a range from 0 degrees to 45 degrees relative to a normal to the surface of the multilayer photonic structure.

19. The article of manufacture of claim 17 wherein the multilayer photonic structure is incorporated in a coating.

20. The article of manufacture of claim 19 wherein the coating is a paint.