Cavity resonator for atomic frequency standard

• US 4,495,478 A
• Filed: 02/16/1983
• Issued: 01/22/1985
• Est. Priority Date: 02/16/1983
• Status: Expired due to Fees

• Current Assignee: Litton Systems Incorporated
• Original Assignee: Litton Systems Incorporated
• Inventors: Williams, Howard E., Kwon, Tae M.
• Primary Examiner(s): Grimm, Siegfried H.
• Application Number:
  US06/467,061
• Time in Patent Office: 706 Days
• Field of Search: 331/3, 331/94.1, 250/251, 324/304, 324/305, 324/313, 333/227, 333/228, 333/230
• US Class Current: 333/230
• CPC Class Codes: H01P 7/06 Cavity resonators
• CPC Class Codes: H03L 7/26 using energy levels of molecules, atoms, or subatomic particles as a frequency reference

Abstract

An improved microwave cavity resonator for use in vapor-cell atomic frequency standards. The resonator comprises a generally-rectangular hollow metallic body designed to support the TE₁₀₁ mode of standing wave. A dielectric element is positioned within the cavity to concentrate electro-magnetic field so that a compact design is achieved and so that a preselected, substantially uniform magnetic field will be coupled into an alkali metal vapor absorption cell within the resonator. Means are provided for mounting elements of an excitation circuit to preferentially excite the desired TE₁₀₁ mode.

Claims

1. A cavity resonator for a vapor cell atomic frequency standard comprising, in combination:

(a) a substantially rectangular body having an internal cavity for supporting TE₁₀₁ mode electromagnetic energy; and

(b) means for preferentially orienting said TE₁₀₁ mode electromagnetic energy.

2. A cavity resonator as defined in claim 1 further characterized in that said internal cavity includes a substantially planar element of dielectric material.

3. A cavity resonator as defined in claim 2 wherein said rectangular body further comprises:

(a) a cap; and

(b) a lower body.

4. A cavity resonator as defined in claim 3 wherein said dielectric element is located substantially within said cap.

5. A cavity resonator as defined in claim 4 wherein said means for preferentially orienting said TE₁₀₁ mode electromagnetic energy is further characterized in that said dielectric element includes a slot arranged to preferentially mount a radiative element within said cavity.

6. A cavity resonator as defined in claim 5 wherein said slot is adapted to receive a length of waveguide.

7. A cavity resonator as defined in claim 6 further characterized in that said dielectric element further includes a second slot for accepting a cavity tuning screw.

8. A cavity resonator as defined in claim 7 wherein said slots are located within the opposed major surfaces of said substantially planar element of dielectric material.

9. A cavity resonator as defined in claim 1 wherein said body includes apertures in opposed end walls for mounting optical lenses.

10. A cavity resonator as defined in claim 9 further including means for mounting a photodetector.

11. A TE₁₀₁ mode cavity resonator comprising in combination:

(a) a body comprising a cap and a lower body and having a substantially rectangular internal cavity;

(b) said body having a pair of apertures at opposed ends thereof for mounting optical lenses;

(c) a substantially planar dielectric element within said cap; and

(d) means for preferentially ordering electromagnetic energy with said cavity.