Atomic frequency standard having microwave loop around absorption cell
US4405905A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 12, 1981 |
| Grant date | Sep 20, 1983 |
| Priority date | — |
| Expiry date | Jan 12, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/26
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The atomic frequency standard comprises a source of light of a given spectral component, comprising a lamp 2 and an isotopic filter 3. The light arriving in an Rb 87 cell 4 empties the hyperfine level F=1 by optical pumping. Microwave excitation produced by a loop 5 causes the atoms which populated the level F=2, m.sub.F =0, to fall back to the level F=1, m.sub.F =0. Filling of the latter level reduces the transparency of the cell 4, which phenomenon is detected by a photoelectric cell 6 and permits tuning of the microwave excitation to the hyperfine transition frequency. The electromagnetic wave produced by the loop 5 is progressive, which, by the Doppler effect, increases the width of the absorption line of the cell. This increase makes it possible to reduce the control time constant and consequently makes it possible to have a compact frequency standard, with a rapid control action, which can operate in an unfavorable environment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.