Claims
- 1. An apparatus for efficient high-frequency energy coupling in radiation-assisted field emission, the apparatus comprising:
a radiation source configured to emit an electromagnetic field; an emitting surface configured to receive at least one electromagnetic field, the emitting surface further configured with a diameter smaller than the wavelength of the effective electromagnetic field, wherein the emitting surface emits an oscillating unneling electron current, the tunneling electron current responsive to the electromagnetic field; and a transmission device coupled to the emitting surface, the transmission device configured to present the oscillating tunneling electron current with a high impedance, the output power responsive to the high impedance.
- 2. The apparatus of claim 1, wherein the transmission device impedance is less than the impedance required to produce appreciable negative feedback sufficient to reduce the output power from the transmission device.
- 3. The apparatus of claim 1, wherein the impedance of the transmission device is tapered over a short distance.
- 4. The apparatus of claim 1, wherein the transmission device is a single conductor propagating a transverse magnetic surface wave.
- 5. The apparatus of claim 4, wherein the single conductor is coated with a dielectric.
- 6. The apparatus of claim 4, wherein the thickness of the dielectric is greater than the diameter of the single conductor.
- 7. The apparatus of claim 4, wherein the length of the dielectric coating along the conductor is greater than or equal to three times the outer radius of the dielectric coating.
- 8. The apparatus of claim 4, wherein the conductor is corrugated.
- 9. The apparatus of claim 1, wherein the transmission device is configured with a ferrite coating.
- 10. The apparatus of claims 9, wherein a static magnetic field is applied parallel to the axis of the transmission device.
- 11. The apparatus of claim 9, wherein in the ferrite material comprises strontium-hexaferrite.
- 12. The apparatus of claim 1, wherein the transmission device comprises a conducting ferrite.
- 13. The apparatus of claim 12, wherein a static magnetic field is applied parallel to the axis of the transmission device.
- 14. The apparatus of claim 12, wherein the ferrite material comprises strontium-hexaferrite.
- 15. The apparatus of claim 1, wherein the emitting surface and the transmission device comprise a carbon nanotube.
- 16. The apparatus of claim 15, further comprising a second carbon nanotube, the carbon nanotubes forming the emitting surface and the transmission device, the nanotubes further joined together at a common junction, the junction coupled to a load.
- 17. The apparatus of claim 1, wherein the transmission device comprises two or more parallel conductors each having an emitting surface.
- 18. The apparatus of claim 1, wherein the transmission device comprises a helical conductor.
- 19. The apparatus of claim 1, wherein the transmission device comprises an antenna, the antenna configured to have a high radiation resistance.
- 20. The apparatus of claim 19, wherein the antenna is coupled with a receiving antenna.
- 21. The apparatus of claim 20, wherein the receiving antenna comprises a dipole antenna.
- 22. The apparatus of claim 21, wherein the receiving antenna comprises a log periodic antenna.
- 23. The apparatus of claim 22, wherein the receiving antenna comprises a log periodic dipole zigzag antenna.
- 24. The apparatus of claim 21, wherein the dipole antenna comprises at least two concentric annular rings.
- 25. The apparatus of claim 20, wherein the receiving antenna comprises a plurality of concentric annular rings, the annular rings connected to form a log periodic antenna.
- 26. The apparatus of claim 19, wherein the antenna comprises a single conductor, the length of the conductor greater than the wavelength of the oscillating tunneling electron current.
- 27. The apparatus of claim 19, wherein the antenna comprises a resonant monopole antenna, the resonant antenna having a total length equal to an integer multiple of one-quarter of the wavelength of the oscillating tunneling electron current.
- 28. The apparatus of claim 27, wherein the resonant antenna is configured with a distal end and a proximal end, the proximal end switchably coupled with the emitting surface.
- 29. The apparatus of claim 27, wherein the resonant antenna is configured with a distal end and a proximal end, the proximal end coupled with the electron emitting surface, the distal end further switchably coupled with a reflective impedance.
- 30. The apparatus of claims 29, further comprising a plurality of resonant antennas, each further switchably coupled with a reflective impedance.
- 31. The apparatus of claim 19, wherein the antenna comprises a resonant antenna.
- 32. The apparatus of claim 31, wherein the resonant antenna is configured as a folded monopole antenna, the length of each fold an integer multiple of one-quarter of the wavelength of the oscillating tunneling electron current.
- 33. The apparatus of claims 19, wherein the antenna is configured as a plurality of resonant antennas, each resonant antenna configured with a distal end and a proximal end, each proximal end switchably coupled with the electron emitting surface.
- 34. The apparatus of claim 1, wherein the transmission device comprises a dielectric waveguide.
- 35. The apparatus of claim 1, wherein the transmission device comprises a lens.
- 36. The apparatus of claim 1, wherein the transmission device comprises a diffraction grating.
- 37. The apparatus of claim 1, wherein the transmission device comprises a mirror.
- 38. The apparatus of claim 1, wherein the emitting surface is biased with a static electric field that has a range of 2 to 9 Volts/nm.
- 39. The apparatus of claim 38, wherein the static electric field is pulsed, the pulse duration being no more than one microsecond.
- 40. The apparatus of claim 1, wherein the electromagnetic field is pulsed.
- 41. The apparatus of claim 1, wherein the electromagnetic field is directed by an optical fiber.
- 42. The apparatus of claim 1, wherein the emitting surface comprises multiple emitter sites.
- 43. The apparatus of claim 1, wherein semiconducting inclusions are dispersed in the emitting surface.
- 44. The apparatus of claim 1, wherein the emitting surface is configured with one of the group consisting of microprotrusions and macrooutgrowths.
- 45. The apparatus of claim 1, wherein the emitting surface is embedded with a material selected from the group consisting of silver, aluminum, and gallium to produce surface plasmons.
- 46. The apparatus of claim 1, wherein the wavelength of the electromagnetic field is selected such that one photon will elevate a tunneling electron above the potential barrier at the emitting surface to an energy where one complete cycle between the classical turning points of the tunneling electron reinforces the wave function of the tunneling electron.
- 47. The apparatus of claim 1, wherein the wavelength of the electromagnetic field is selected such that there is little or no resonant reinforcing of the wave function of the tunneling electron.
- 48. The apparatus of claim 1, wherein a current is coupled to the emitting surface, the emitting surface emitting an electromagnetic field.
- 49. A method for selecting the impedance of a transmission device, the method comprising:
increasing the impedance of a coupling between a transmission device and an emitting surface in a radiation-assisted field emission device, the emitting surface generating a tunneling electron current, and selecting the impedance where the decrease in coupling energy resulting form the incremental negative current feedback produced by the increased impedance of the coupling between the transmission device and the emitting surface exceeds the incremental increase in coupling energy from the increased impedance.
- 50. The method of claim 49, wherein the impedance of the transmission device rapidly decreases away from the coupling between the emitting surface and the transmission device.
- 51. A system for high-frequency energy coupling to a field emission current source, the system comprising:
an evacuated chamber; a radiation source configured to emit an electromagnetic field; an emitting surface configured to receive at least one electromagnetic field, the emitting surface further configured with a diameter smaller than the wavelength of the effective electromagnetic field, wherein the emitting surface emits an oscillating unneling electron current, the tunneling electron current responsive to the electromagnetic field; and a transmission device coupled to the emitting surface, wherein the transmission device presents the oscillating tunneling electron current with a high impedance, the output power responsive to the high impedance.
- 52. The system of claim 51, wherein the impedance of the transmission device is configured to create a photomixer, the photomixer responsive to the frequency of the electromagnetic radiation and the impedance of the transmission.
- 53. The system of claim 51, wherein the transmission device is configured to pass the energy at selected harmonics or mixer terms that are formed in the tunneling electron current oscillations.
- 54. The system of claim 51, wherein the emitting surface and the transmission device are located within a cavity of the radiation source.
- 55. The system of claim 51, wherein the system is configured to input high-frequency energy to create electric field oscillations at the emitting surface to modulate the field emission current and modulate the radiation from one or more sources of radiation.
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of and claims priority to U.S. Patent Application No. 60/387,837, filed on Jun. 11, 2002 and entitled “MEANS AND METHODS FOR THE EFFICIENT COUPLING OF HIGH-FREQUENCY ENERGY TO AND FROM THE EMITTING TIP IN PHOTON-ASSISTED FIELD EMISSION” and which is incorporated herein by reference.
Provisional Applications (1)
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Number |
Date |
Country |
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60387837 |
Jun 2002 |
US |