Microfabricated vapor cells filled with a cesium dispensing paste for miniature atomic clocks

• Published in: Applied physics letters Vol. 110; no. 16
• Main Authors: Maurice, V., Rutkowski, J., Kroemer, E., Bargiel, S., Passilly, N., Boudot, R., Gorecki, C., Mauri, L., Moraja, M.
• Format: Journal Article
• Language: English
• Published: American Institute of Physics 17-04-2017
• Subjects: Acoustics; Engineering Sciences; Materials; Micro and nanotechnologies; Microelectronics; Other
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4981772

A method for filling alkali vapor cells with cesium from a dispensing paste is proposed and its compliance with miniature atomic clock applications is evaluated. The paste is an organic-inorganic composition of cesium molybdate, zirconium-aluminum powder, and a hybrid organic-inorganic binder. It is compatible with collective deposition processes such as micro-drop dispensing, which can be done under ambient atmosphere at the wafer-level. After deposition and sealing by anodic bonding, cesium is released from the consolidated paste through local heating with a high power laser. Linear absorption signals have been observed over one year in several cells, showing a stable atomic density. For further validation of this technology for clock applications, one cell has been implemented in a coherent population trapping clock setup to monitor its frequency stability. A fractional frequency aging rate around –4.4 × 10−12 per day has been observed, which is compliant with a clock frequency instability below 1 × 10−11 at one day integration time. This filling method can drastically reduce the cost and the complexity of alkali vapor cell fabrication.