Apodized diffraction grating with improved dynamic range

• US 20060056028A1
• Filed: 09/13/2004
• Published: 03/16/2006
• Est. Priority Date: 09/13/2004
• Status: Abandoned Application

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Wildnauer, Kenneth R.
• Application Number:
  US10/939,674
• Publication Number:
  US 20060056028A1
• Time in Patent Office: Days
• US Class Current: 359/575
• CPC Class Codes: G02B 5/1809 with pitch less than or comparable to the wavelength
• CPC Class Codes: G02B 5/1857 using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams

Abstract

An optical diffraction grating includes a substrate and a diffraction surface comprising, for example, diffraction grooves. The diffraction grating has a spatially varying diffraction efficiency which increases or decreases as a function of distance from a reference location at which an incident light beam is received at the grating. Spatially varying the diffraction efficiency of the grating may be accomplished by selectively changing or modifying one or more grating design parameters such as the shape, size, depth, profile, pitch, and optical properties of the diffraction grooves at predetermined locations on the grating.

Claims

1. An optical grating, comprising:

a substrate; and

a diffraction surface located on said substrate, said diffraction surface varying in diffraction efficiency as a function of distance from a reference location on said substrate.

2. The optical grating of claim 1, wherein said diffraction efficiency of said diffraction surface decreases as said distance from said reference location increases.

3. The optical grating of claim 1, wherein said diffraction efficiency of said diffraction surface increases as said distance from said reference location increases.

4. The optical grating of claim 1, wherein said diffraction surface comprises diffraction grooves, and the depth of said diffraction grooves decreases as said distance from said reference location increases.

5. The optical grating of claim 1, wherein said diffraction surface comprises diffraction grooves, and the pitch of said diffraction grooves increases as said distance from said reference location increases.

6. The optical grating of claim 1, wherein said diffraction surface comprises diffraction grooves, and the profile of said diffraction grooves changes as said distance from said reference location increases.

7. The optical grating of claim 1, wherein said diffraction surface comprises diffraction grooves, and the surface quality of said diffraction grooves decreases as said distance from said reference location increases.

8. The optical grating of claim 1, wherein said diffraction surface comprises diffraction grooves, and the refractive index contrast of said diffraction grooves decreases as said distance from said reference location increases.

9. The optical grating of claim 1, wherein said diffraction surface comprises diffraction grooves, and the reflectivity of said diffraction grooves decreases as said distance from said reference location increases.

10. The optical grating of claim 1, wherein said diffraction surface is planar.

11. The optical grating of claim 1, wherein said diffraction surface is concave relative to an incident light beam.

12. The optical grating of claim 1, wherein said diffraction surface is convex relative to an incident light beam.

13. The optical grating of claim 1, wherein said grating is optically transmissive.

14. The optical grating of claim 1, wherein said grating is optically reflective.

15. The optical grating of claim 1, wherein said diffraction surface includes diffraction efficiency regions, each having a progressively lower diffraction efficiency as said distance from said reference location increases.

16. The optical grating of claim 1, wherein said diffraction surface includes diffraction efficiency regions, each having a progressively higher diffraction efficiency as said distance from said reference location increases.

17. An optical grating, comprising:

a substrate; and

diffraction means located on said substrate, said diffraction means varying in diffraction efficiency as a function of distance from a reference location on said substrate.

18. The optical grating of claim 17, wherein said diffraction efficiency of said diffraction surface decreases as said distance from said reference location increases.

19. The optical grating of claim 17, wherein said diffraction efficiency of said diffraction surface increases as said distance from said reference location increases.

20. The optical grating of claim 17, wherein said diffraction means comprises diffraction grooves, and the depth of said diffraction grooves decreases as said distance from said reference location increases.

21. The optical grating of claim 17, wherein said diffraction means comprises diffraction grooves, and the pitch of said diffraction grooves increases as said distance from said reference location increases.

22. The optical grating of claim 17, wherein said diffraction means comprises diffraction grooves, and the profile of said diffraction grooves changes as said distance from said reference location increases.

23. The optical grating of claim 17, wherein said diffraction means comprises diffraction grooves, and the surface quality of said diffraction grooves decreases as said distance from said reference location increases.

24. The optical grating of claim 17, wherein said diffraction means comprises diffraction grooves, and the refractive index contrast of said diffraction grooves decreases as said distance from said reference location increases.

25. The optical grating of claim 17, wherein said diffraction means comprises diffraction grooves, and the reflectivity of said diffraction grooves decreases as said distance from said reference location increases.