Cs vapor microcells with Ne-He buffer gas mixture for high

We report on the characterization of Cs vapor microfabricated cells filled with a Ne-He buffer gas mixture using coherent population trapping (CPT) spectroscopy. The temperature dependence of the Cs clock frequency is found to be canceled at the first order around a so-called inversion temperature higher than 80 degrees C whose value depends on the buffer gas partial pressure ratio. This buffer gas mixture could be well-adapted for the development of miniature atomic clocks devoted to be used in specific applications such as defense and avionic systems with high operating temperature environment (typically higher than 85 degrees C). This solution suggests an alternative to buffer gas mixtures generally used in optically-pumped vapor cell atomic clocks. (C) 2015 Optical Society of America