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

Abstract

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.

Chip-scale atomic devices

“…132 The turning point temperature can be increased The ðCs 2 MoO 4 Þ=Zr=Al mixture can also be mixed with a paste-like binder material and deposited into cells using an automated epoxy dispensing tool, allowing for much faster deposition of the required materials. 134 In cells filled using this method containing a Ne buffer gas alone, a frequency drift below 5 Â 10 À12 /day was measured, 134 indicating that there are no significant changes in buffer gas pressure occurring due to the presence of the unreacted precursors. A similar fabrication process was developed that used an alkali dichromate in a titanium tablet.…”

Technological Assessment of MEMS Alkali Vapor Cells for Atomic References

“…Finally, the laser-induced dispenser activation must be performed dispenser-by-dispenser with great precision, as previously mentioned. To overcome the abovementioned setbacks, the mesh-printing of pastes followed by back-up dispensing has been demonstrated [82].…”

Alkali Vapor MEMS Cells Technology toward High-Vacuum Self-Pumping MEMS Cell for Atomic Spectroscopy

“…The purpose of the Project was the development of the first European miniature atomic clock, what was achieved [ 16 ]. The laser-induced cesium vapor introduction method from solid-state dispensers is the basis of the technology of MEMS optical cells developed in the author’s mother’s unit, but also at the Université de Franche-Comté/FEMTO-ST, Besancon, France [ 21 , 22 ].…”