Wire grid polarizer

• US 6,532,111 B2
• Filed: 03/05/2001
• Issued: 03/11/2003
• Est. Priority Date: 03/05/2001
• Status: Active Grant

• Current Assignee: Moxtek (Polatechno Co.,Ltd.)
• Original Assignee: Eastman Kodak Company
• Inventors: Kurtz, Andrew F., Mi, Xiang-Dong, Ramanujan, Sujatha
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): O'Neill, Gary
• Application Number:
  US09/799,281
• Publication Number:
  US 20020122235A1
• Time in Patent Office: 736 Days
• Field of Search: 359/619, 359/628, 359/483, 359/485, 359/486, 353/20
• US Class Current: 359/485.05
• CPC Class Codes: G02B 5/3058 comprising electrically conductive elements, e.g. wire grids, conductive particles
• CPC Class Codes: H01Q 15/24 Polarising devices; Polarisation filters H01Q15/12, H01Q15/22 take precedence

Abstract

A wire grid polarizer (300) for polarizing an incident light beam (130) comprises a substrate having a first surface. A grid or array of parallel, elongated, composite wires (310) is disposed on the first surface (307), and each of the adjacent wires are spaced apart on a grid period less than a wavelength of incident light. Each of the wires comprises an intra-wire substructure (315) of alternating elongated metal (330a-i) wires and elongated dielectric layers (350a-i).

Claims

1. A wire grid polarizer for polarizing an incident light beam, comprising:

a substrate having a surface;

an array of parallel, elongated, composite wires disposed on said surface, wherein each of said composite wires are spaced apart at a grid period less than a wavelength of said incident light;

wherein each of said composite wires comprises an intra-wire substructure of alternating elongated metal wires and elongated dielectric layers; and

wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires.

2. A wire grid polarizer according to claim 1 wherein said wire grid polarizer is oriented at an angle relative to said incident light beam such that said wire grid polarizer functions as a polarization beam spliter and separates a transmitted polarized beam and a reflected polarized beam from said angle of said incident light beam.

3. A wire grid polarizer according to claim 1 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers supports resonance enhanced tunneling through said elongated metal wires, thereby enhancing transmission of the light of the polarization state orthogonal to said array of composite.

4. A wire grid polarizer according to claim 1 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least one of said dielectric layers.

5. A wire grid polarizer according to claim 1 wherein each of said intra-wire substructures has a total thickness of between approximately 0.2 to 3.0 μ

m.

6. A wire grid polarizer according to claim 1 wherein said elongated metal wires are selected from a group comprised of aluminum, silver, or gold.

7. A wire grid polarizer according to claim 1 wherein said enlongated dielectric layers are selected from a group comprised of MgF2, SiO2, or TiO2.

8. A wire grid polarizer according to claim 1 wherein said substrate is made of glass.

9. A wire grid polarizer according to claim 1 where said composite wires have a rectangular shaped cross-section.

10. A wire grid polarizer according to claim 1 wherein said incident light is within the range of approximately 0.4 to 1.6 μ

m in the electro-magnetic spectrum.

34. A wire grid polarizer according to claim 1 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers provides enhanced transmission of the light of the polarization state orthogonal to said of array of composite wires, thereby enhancing either the transmitted contrast of said orthogonal polarization state or the reflected contrast of the light of the polarization state parallel to said array of composite wires, or both.

11. A wire grid polarizer for polarizing an incident light beam, comprising:

a substrate having a surface;

an array of parallel, elongated, composite wires disposed on said surface, wherein each of said composite wires are spaced apart from adjacent wires at a grid period less than a wavelength of said incident light; and

wherein each of said composite wires comprises an intra-wire substructure of multiple alternating elongated metal wires and elongated dielectric layers, such that each intra-wire substructure creates a metallo-dielectric photonic band gap structure which enables resonance enhanced tunneling through said elongated metal wires.

12. A wire grid polarizer according to claim 11 which is oriented at an angle relative to said incident light beam such that it functions as a polarization beam splitter and separates a transmitted polarized beam and a reflected polarized beam from said incident light beam.

13. A wire grid polarizer according to claim 11 wherein said intra-wire substructure of alternating elongated wires and elongated dielectric layers supports resonance enhanced tunneling through said elongated metal wires, thereby enhancing transmission of the light of the polarization state orthogonal to said array of composite wires.

14. A wire grid polarizer according to claim 11 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least one of said dielectric layers.

15. A wire grid polarizer for polarizing an incident light beam, comprising:

a substrate having a surface;

an array of parallel, elongated, composite wires disposed on said surface, wherein each of said composite wires are spaced apart from adjacent wires at a grid period less than a wavelength of incident light;

wherein each of said composite wires comprises an intra-wire substructure of periodically spaced alternating elongated metal wires and elongated dielectric layers; and

wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires.

16. A wire grid polarizer according to claim 15 wherein said wire grid polarizer is oriented at an angle relative to said incident light beam such that said wire grid polarizer functions as a polarization beam splitter and separates a transmitted polarized beam and a reflected polarized beam from said incident light beam.

17. A wire grid polarizer according to claim 15 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers supports resonance enhanced tunneling through said elongated metal wires, thereby enhancing transmission of the light of the polarization state orthogonal to said array of composite wires.

18. A wire grid polarizer according to claim 15 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least one of said dielectric layers.

35. A wire grid polarizer according to claim 15 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers provides enhanced transmission of the light of the polarization state orthogonal to said array of composite wires, thereby enhancing either the transmitted contrast of said orthogonal polarization state or the reflected contrast of the light of the polarization state parallel to said array of composite wires, or both.

19. A broadband wire grid polarizer for polarizing an incident light beam, wherein said light beam is part of the visible spectrum, comprising:

a substrate having a surface;

an array of parallel, elongated, composite wires disposed on said surface, wherein each of said composite wires are spaced apart from said adjacent wires at a grid period less than a wavelength of said incident visible light;

wherein each of said composite wires comprises an intra-wire substructure of alternating elongated metal wires and elongated dielectric layers; and

wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires.

20. A wire grid polarizer according to claim 19 wherein said wire grid polarizer is oriented at an angle relative to said incident light beam such that it functions as a polarization beam splitter and separates a transmitted polarized beam and a reflected polarized beam from said incident light beam.

21. A wire grid polarizer according to claim 19 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers supports resonance enhanced tunneling through said elongated metal wires, thereby enhancing transmission of the light of the polarization state of orthogonal to said array of composite wires.

22. A wire grid polarizer according to claim 19 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said dielectric layers.

36. A wire grid polarizer according to claim 19 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers provides enhanced transmission of the light of the polarization state orthogonal to said of array of composite wires, thereby enhancing either the transmitted contrast of said orthogonal polarization state of the reflected contrast of the light of the polarization state parallel to said array of composite wires, or both.

23. A wire grid polarizer for polarizing an incident light beam, comprising:

a substrate having a surface;

an array of parallel, elongated, composite wires disposed on said surface, wherein each of said composite wires are spaced apart from adjacent wires at a grid period less than a wavelength of said incident light;

wherein each of said composite wires comprises an intra-wire substructure of quasi-periodically spaced alternating elongated metal wires and elongated dielectric layers; and

wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires.

24. A wire grid polarizer according to claim 23 wherein said wire grid polarizer is oriented at an angle relative to said incident light beam such that it functions as a polarization beam splitter and separates a transmitted polarized beam and a reflected polarized beam from said incident light beam.

25. A wire grid polarizer according to claim 23 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers supports resonance enhanced tunneling through said elongated metal wires, thereby enhancing transmission of the light of the polarization state orthogonal to said array of composite wires.

26. A wire grid polarizer according to claim 23 wherein said intra-wire substructure of alternating elongated wires and elongated dielectric layers comprises at least one of said dielectric layers.

27. A wire grid polarizer for polarizing incident light comprising:

a substrate;

an array of parallel elongated composite wires formed on said substrate;

wherein said elongated composite wires are formed with a structure of alternating layers of metal and dielectric;

wherein each of said metal layers are comprised of an elongated metal wire;

wherein said dielectric layers are each comprised of an elongated strip of dielectric material;

wherein said elongated strips of dielectric material in each layer overlay said elongated metal wires;

wherein a thickness of at least one said dielectric layers is greater than a thickness of at least a second dielectric layer; and

wherein said elongated composite wires formed with said structure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires.

28. A wire grid polarizer according to claim 27 wherein said wire grid polarizer is oriented at an angle relative to said incident light beam such that it functions as a polarization beam splitter and separates a transmitted polarized beam and a reflected polarized beam from said incident light beam.

29. A wire grid polarizer according to claim 27 wherein said elongated composite formed with a structure of alternating elongated metal wires and elongated dielectric layers supports resonance enhanced tunneling through said elongated metal mires, thereby enhancing transmission of the light of the polarization state orthogonal to said array of elongated composite wires.

37. A wire grid polarizer according to claim 27 wherein said composite wires formed with said structure of alternating layers of metal and dielectric provides enhanced transmission of the light of the polarization state orthogonal to said of array of composite wires, thereby enhancing either the transmitted contrast of said orthogonal polarization state or the reflected contrast of the light of the polarization state parallel to said array of composite wires, or both.

30. A wire grid polarizer for polarizing an incident light beam, comprising:

a substrate;

an array of parallel, elongated, composite wires disposed on said substrate, wherein each of said composite wires are spaced apart from adjacent composite wires at a grid period less than a wavelength of said incident light;

wherein each of said composite wires comprises alternating elongated metal wires and elongated dielectric layers;

wherein a width of each of said composite wires is in a range of 40%-60% of said grid period; and

wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires.

31. A wire grid polarizer for polarizing an incident light beam, comprising:

a substrate;

an array of parallel, elongated, composite wires disposed on said substrate, wherein each of said composite wires are spaced apart from adjacent composite wires at a grid period less than a wavelength of said incident light;

wherein each of said composite wires comprises alternating elongated metal wires and elongated dielectric layers;

wherein a width of each of said composite wires is in a range of 40%-60% of said grid period;

wherein each of said composite wires has a total thickness between approximately 0.2 and 3.0 μ

m; and

wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires.

32. A wire grid polarizer for polarizing an incident light beam, comprising:

a substrate;

an array of parallel, elongated, composite wires disposed on said substrate, wherein each of said composite wires are spaced apart from adjacent composite wires at a grid period less than a wavelength of said incident light;

wherein each of said composite wires comprises alternating elongated metal wires and elongated dielectric layers;

wherein a width of each of said composite wires is in a range of 40%-60% of said grid period;

wherein each of said metal wires has a total thickness between approximately 1-4 skin depths; and

wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires.

33. A wire grid polarizer for polarizing an incident light beam, comprising:

a substrate;

an array of parallel, elongated, composite wires disposed on said substrate, wherein each of said composite wires are spaced apart at a grid period less than a wavelength of said incident light;

wherein each of said composite wires comprises alternating elongated metal wires and elongated dielectric layers;

wherein each of said metal wires has a total thickness of between approximately 1-4 skin depths; and

wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires.