Cs vapor microcells with Ne-He buffer gas mixture for high operation-temperature miniature atomic clocks

Area of Science:

• Atomic, Molecular, and Optical Physics
• Microfabrication and Sensor Technology

Background:

• Optically-pumped vapor cell atomic clocks are crucial for precise timekeeping.
• Existing designs face limitations in high-temperature operational environments.
• Cesium (Cs) vapor cells are commonly used, but their frequency is temperature-dependent.

Purpose of the Study:

• To characterize a novel Ne-He buffer gas mixture in Cs vapor microfabricated cells.
• To investigate the temperature dependence of Cs clock frequency using coherent population trapping (CPT) spectroscopy.
• To assess the suitability of this mixture for high-temperature atomic clock applications.

Main Methods:

• Fabrication of microfabricated cesium vapor cells.
• Filling cells with a specific Ne-He buffer gas mixture.
• Characterization using coherent population trapping (CPT) spectroscopy.
• Analysis of temperature dependence of Cs clock frequency.

Main Results:

• The temperature dependence of the Cs clock frequency was found to be canceled at first order around an inversion temperature exceeding 80°C.
• The specific inversion temperature is dependent on the buffer gas partial pressure ratio.
• This Ne-He mixture offers an alternative to conventional buffer gases.

Conclusions:

• The Ne-He buffer gas mixture enables first-order temperature compensation of Cs clock frequency.
• This characteristic makes the microfabricated cells suitable for high-temperature applications (above 85°C).
• The developed solution is a viable alternative for miniature atomic clocks in defense and avionic systems.