Key members:

Thermal cesium beam clocks are the type of commercial atomic clocks offering the best accuracy and long-term stability. Today’s commercially available cesium beam clocks rely on magnetic deflection for atomic state preparation, which results in non-ideal use of the atomic beam flux and critical beam alignment. By introducing laser optical pumping for atomic state preparation and detection, the atomic beam flux can be fully exploited and thus the clock stability can be improved by one order of magnitude without impact on the clock’s lifetime.

This project aims to improve on the knowledge of specifications for the laser diodes required for such thermal cesium atomic clocks. In particular, the impact of the lasers’ emission linewidth on clock stability is still not sufficiently well known and will be studied experimentally. For this purpose, several laser diodes with different emission linewidth will be characterized for their spectral properties, implemented into the atomic clock, and the obtained clock stability will be measured and analyzed. The expected results will contribute to an improved understanding and predictability of thermal cesium beam atomic clocks with laser optical interrogation.


scheme of magnetic and optical Cs beam clocks

Left-hand side: scheme of a conventional cesium thermal beam clock with magnetic deflection Yellow: atomic beam. Read: magnets. Right-hand side: scheme of a laser-pumped cesium thermal beam clock. Red: laser beams.


This project is conducted in collaboration with Oscilloquartz SA.

Funding: European Space Agency ESA