First-order cancellation of the Cs clock frequency temperature-dependence in Ne-Ar buffer gas mixture.

Through the detection of Coherent Population Trapping (CPT) resonances, we demonstrate the temperature-dependence cancellation of the Cs clock frequency in microfabricated vapor cells filled with a mixture of Ne and Ar. The inversion temperature at which the Cs clock frequency temperature sensitivity is greatly reduced only depends on the partial pressure of buffer gases and is measured to be lower than 80°C as expected with simple theoretical calculations. These results are important for the development of state-of-the-art Cs vapor cell clocks with improved long-term frequency stability.