Structures and methods for coupling energy from an electromagnetic wave

• US 7,253,426 B2
• Filed: 10/05/2005
• Issued: 08/07/2007
• Est. Priority Date: 09/30/2005
• Status: Expired due to Fees

• Current Assignee: Advanced Plasmonics, Inc.
• Original Assignee: Virgin Island Microsystems, Inc.
• Inventors: Davidson, Mark, Gorrell, Jonathan, Hart, Paul, Maines, Michael, Gasparov, Lev
• Primary Examiner(s): Wells; Nikita
• Assistant Examiner(s): Hashmi; Zia R.
• Application Number:
  US11/243,476
• Publication Number:
  US 20070085039A1
• Time in Patent Office: 671 Days
• Field of Search: None
• US Class Current: 250/200
• CPC Class Codes: H01J 25/00 Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons details of transit-time tubes H01J23/00; particle accelerators H05H

Abstract

A device couples energy from an electromagnetic wave to charged particles in a beam. The device includes a micro-resonant structure and a cathode for providing electrons along a path. The micro-resonant structure, on receiving the electromagnetic wave, generates a varying field in a space including a portion of the path. Electrons are deflected or angularly modulated to a second path.

Claims

1. A device for coupling energy from an electromagnetic wave to a charged particle beam, the device comprising:

an ultra-small micro-resonant structure having a surface for receiving the electromagnetic wave, said ultra-small micro-resonant structure constructed and adapted to generate a varying field on receiving the electromagnetic wave, and to cause a charged particle beam approaching the varying field to be modulated; and

a source providing the charged particle beam, wherein the charged particle beam comprises particles selected from the group comprising;

electrons, positive ions, negative ions, and protons, said particle beam being provided along a generally-straight first path toward the varying field,

wherein the micro-resonant structure includes a region with varying field, wherein the charged particle beam exits the region along a generally-straight second path distinct from the first path, wherein an angle between the first path and the second path is related, at least in part, to a magnitude of the energy coupled from the electromagnetic wave to the charge particle beam.

2. A device for coupling energy from an electromagnetic wave to a charged particle beam, the device comprising:

an ultra-small micro-resonant structure constructed and adapted to generate a varying field on receiving the electromagnetic wave, and to cause a charged particle beam approaching the varying field to be angularly modulated.

3. A device as in claim 2 further comprising:

a source providing the charged particle beam.

4. A device as in claim 2 wherein the charged particle beam comprises particles selected from the group comprising:

electrons, positive ions, negative ions, positrons and protons.

5. A device as in claim 2 wherein said particle beam is provided along a first path toward the varying field.

6. A device as in claim 5, wherein the first path is generally straight.

7. A device as in claim 2 wherein the micro-resonant structure comprises a surface for receiving the electromagnetic wave.

8. A device as in claim 7 wherein the surface comprises a metal selected from the group comprising:

silver (Ag), gold (Au), copper (Cu) and alloys.

9. A device as in claim 3 further comprising a substrate on which the micro-resonant structure is formed.

10. A device as in claim 9 where said source is formed on said substrate.

11. A device as in claim 2, further comprising an intensifier for increasing the magnitude of the varying field.

12. A device as in claim 11, wherein the intensifier comprises a cavity in said micro-resonant structure having a gap.

13. A device as in claim 12 wherein the cavity has a semi-circular shape.

14. A device as in claim 12 wherein the cavity has a rectangular shape.

15. A device as in claim 12, wherein the varying field across the gap is intensified.

16. A device as in claim 12, wherein the charged particle beam enters the cavity transverse to the gap.

17. A device as in claim 12, wherein the charged particle beam is angularly modulated by the varying field across the gap.

18. A device as in claim 12 wherein the charged particle beam exits the cavity along a second path distinct from the first path.

19. A device as in claim 18, wherein the second path is generally straight.

20. A device as in claim 19, wherein an angle between the first path and the second path is related, at least in part, to a magnitude of the energy coupled from the electromagnetic wave to the charge particle beam.

21. A device as in claim 11, wherein the intensifier comprises an edge of said micro-resonant structure having an adjacent space.

22. A device as in claim 21 wherein the charged particle beam traverses the space adjacent to the edge and is angularly modulated by the varying field.

23. A device as in claim 21 wherein the charged particle beam travels from the space adjacent to the edge on the second path, distinct from said first path, when the charged particle beam has been angularly modulated.

24. A device as in claim 11, wherein the intensifier comprises a corner of the micro-resonant structure.

25. A device as in claim 24, wherein the charged particle beam travels to the space adjacent to the corner and is angularly modulated by the varying field.

26. A device as in claim 25, wherein the charged particle beam travels from the space adjacent to the corner on a second path, distinct from the first path, when the charged particle beam has been angularly modulated.

27. A device as in claim 11 wherein a height of the micro-resonant structure is about a one-quarter wavelength multiple of the wavelength of the electromagnetic wave.

28. A device as in claim 27, wherein the micro-resonant structure comprises a sub-wavelength structure.

29. A device as in claim 28, wherein the micro-resonant structure comprises a nano-scale structure.

30. A device as in claim 29, wherein said micro-resonant structure further comprises a coupler.

31. A device as in claim 30, wherein the coupler comprises an antenna.

32. A method of coupling energy from an electromagnetic wave to a charged particle beam, the method comprising:

providing an ultra-small micro-resonant structure having at least one surface;

receiving energy from the electromagnetic wave on the at least one surface;

generating a varying field around the ultra-small micro-resonant structure;

providing a charged particle beam that approaches the varying field; and

angularly modulating the charged particle beam using the varying field.

33. The method of claim 32, wherein receiving energy from the electromagnetic wave comprises:

receiving the electromagnetic wave on the surface; and

generating a charge density wave on and adjacent to the surface.

34. The method of claim 33, wherein generating the charge density wave comprises exciting plasmons on the surface using the evanescent waves.

35. The method of claim 34, wherein angularly modulating the charged particle beam comprises transversely coupling energy from the varying field to the charged particle beam.

36. The method of claim 35, further comprising intensifying the varying field.

37. The method of claim 36, wherein intensifying the varying field comprises coupling the varying field across a gap of a cavity of the ultra-small micro-resonant structure.

38. The method of claim 37, wherein intensifying the varying field comprises coupling the varying field around a corner of the ultra-small micro-resonant structure.

39. The method of claim 38, wherein intensifying the varying field comprises coupling the varying field around an edge of the micro-resonant structure.

40. The method of claim 39, wherein intensifying the varying field comprises coupling the varying field across a gap between nano-structures.

41. A device comprising:

an ultra-small micro-resonant structure constructed and adapted to receive energy from an electromagnetic wave, and having a field intensifier associated therewith, wherein

a charged particle beam approaching the intensifier on a first path continues on the first path when the ultra-small micro-resonant structure is not receiving energy from an electromagnetic wave, and wherein the charged particle beam approaching the intensifier on the first path continues on a second path, distinct from the first path, when the ultra-small micro-resonant structure is receiving energy from an electromagnetic wave.

42. A device as in claim 41, wherein the size of an angle between said first path and said second path is related, at least in part, to a magnitude of the energy from the electromagnetic wave.

43. A device as in claim 41 wherein, responsive to an electromagnetic wave incident thereon, the ultra-small micro-resonant structure produces a varying field that angularly modulates the charged particle beam to a path distinct from the first path.

44. The device of claim 41, wherein the shape of the ultra-small micro-resonant structure is selected from the group of shapes comprising:

triangles, cubes, rectangles, cylinders and spheres.

45. The device of claim 42, wherein the ultra-small micro-resonant structure comprises a cavity having a gap.

46. The device of claim 45, wherein the charged particle beam approaches the cavity on the first path transverse to the gap.

47. The device of claim 46, wherein the cavity is semi-circular.

48. The device of claim 45, wherein the gap intensifies the varying field.