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US3667066A
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Optically pumped alkali atomic beam frequency standard
Assignee: Bpifrance Financement SA
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Filing: 1969-07-07
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Granted: 1972-05-30
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Expires: 1989-07-07
Abstract
Abstract The frequency standard comprises an oven producing a beam of Rb85 and Rb87, a lamp using Rb85 for enriching the level F 1 of the fundamental state of the atoms of Rb87, a hyperfrequency cavity equalizing the population of the levels F 1, mF 0 and F 2, mF 0 of this state, a lamp using Rb87 or natural Rb filtered by a vat containing Rb85 for producing transitions between the levels F 1 of the fundamental state and an excited level, and a detector completed by an electronic unit coupling a quartz oscillator to the atomic resonance.
Inventors
- 👤 Alfred Kastler
- 👤 Maurice Arditi
- 👤 Pierre Cerez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:12
CPC Classifications
H; H05; H05H; H05H3/00; G; G04; G04F; G04F5/00; G04F5/14
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
194 words
Atomic beam frequency standard according to claim 1, comprising, in combination: an evacuated elongated container; an oven disposed in said container at one end of the container, said oven being adapted to project said beam of atoms in the direction of the other end of the container; means for optical pumping between one of the fundamental levels of the atoms of the beam and a level of an excited state of said atoms; a said cavity of the double type, through which the beam passes after having undergone the optical pumping; means for producing in said cavity an alternating magnetic field, parallel to the continuous field and at a frequency corresponding to the difference of energy between the two levels of the fundamental state of said atoms; optical detection means for directing, on the beam which has passed through the cavity, a detection light at the frequency corresponding to the difference of energy between the other level of the fundamental state and the level of the excited state; and detector means for detecting the light, emitted by the optical detection means, which light has passed through said beam after its passage in the cavity.
Claim 2
Dependent Claim
112 words
Atomic beam frequency standard according to claim 2, wherein the oven contains natural rubidium and produces a beam of atoms of Rb87 and Rb85; the optical pumping means comprise a Rb85 resonance lamp for enriching the level E1 (F 1) of the fundamental state with respect to the level E2 (F 2) of said state of the atoms of Rb87; the cavity is supplied at a frequency equal to 6,834.6 MHz; and the optical detection means comprise a resonance lamp using natural rubidium or Rb87 filtered by a vat of Rb85, the detector receiving the light emitted by the last cited lamp which light has passed through said vat and the beam.
Claim 3
Dependent Claim
110 words
Atomic beam frequency standard according to claim 2, wherein the oven contains natural rubidium and produces a beam of atoms of Rb87 and Rb85; the optical pumping means comprise a resonance lamp using natural rubidium or Rb87 filtered by a vat of Rb85 for enriching the level E2 (F 2) of the fundamental state with respect to the level E1 (F 1) of this state of the atoms of Rb87; the cavity is supplied at a frequency equal to 6,834.6 MHz; and the optical detection means comprise a resonance lamp using Rb85, the detector receiving the light emitted by the last cited lamp which light has passed through the beam.
Claim 4
Dependent Claim
50 words
Atomic beam frequency standard according to claim 2, wherein the oven comprises an elongated body having an axIal blind bore, peripheral channels containing heating elements and an ejector disposed in the neck of the axial bore, said ejector comprising a series of parallel tubes, of small diameter, forming the beam.
Claim 5
Dependent Claim
131 words
Atomic beam frequency standard according to claim 2, comprising an audiofrequency amplifier amplifying the current of the optical detection means, a quartz oscillator operating on a frequency which is an exact sub-multiple of the frequency of the transition between the two levels of the fundamental state, a frequency multiplier multiplying the frequency of the oscillator for deducing the frequency of the pre-cited transition, means for modulating at low frequency the frequency of the multiplier, a phase detector comparing the phase of the modulation with the phase of the current delivered by the amplifier, means for controlling the frequency of the oscillator in response to the signal emitted by the phase detector and a frequency synthesizer deducing, from the frequency of the oscillator, frequencies which are integral numbers in the decimal system.
Claim 6
Dependent Claim
116 words
Atomic beam frequency standard according to claim 2, wherein the oven contains natural rubidium and produces a beam of atoms of Rb87 and Rb85; the optical pumping means comprise a Rb85 resonance lamp filtered by a vat of Rb87 for enriching the level E2 (F 2) of the fundamental state with respect to the levels E1 (F 1) of this state of the atoms of Rb85; the cavity is supplied at a frequency equal to 3,036 MHz; and the means for optical detection comprise a resonance lamp using natural rubidium or Rb87, the detector being a photomultiplier, receiving the light emitted by the last cited lamp which light has passed through said vat and the beam.
Claim 7
Dependent Claim
51 words
Atomic beam frequency standard according to claim 1, wherein said alkali atoms are sodium, potassium or cesium, wherein at least one of the means for optical pumping and means for the optical detection comprise alkali vapor cells placed in an intense magnetic field for modifying the frequency by the Paschen-Back effect.
Claim 8
Dependent Claim
37 words
Atomic beam frequency standard according to claim 1, wherein said alkali atoms are sodium, potassium or cesium, wherein at least one of the means for optical pumping and means for the optical detection comprise a semi-conductor laser.
References Cited (Backward Citations)
US3323008A
Cited
US3360740A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-30 | 1975-11-29 | 1976-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-30 | 1979-11-29 | 1980-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-30 | 1983-11-29 | 1984-05-30 | $7700.00 | Window Closed / Lapsed |