Nuclear spin decoherence time in MEMS atomic vapor cells for applications in quantum technologies

We report on the fabrication and characterization of MEMS atomic vapor cells suitable for applications in miniaturized quantum sensors such as atomic gyroscopes. Our MEMS cells are filled with natural abundance Rb alkali atoms and enriched noble Xe atoms and are operated in the regime of spin exchange optical pumping. The transverse relaxation time T2* of the nuclear spin in 129Xe atoms directly defines the angular random walk parameter of an atomic gyroscope. Using a field switch technique, we measure the dephasing time T2* of the 129Xe isotope as a function of temperature. Our results showing a decrease of T2* from about 1 to 0.4 seconds with an increasing temperature in the range from 80 to 150 °C are in good agreement with a simple theoretical model taking into account the most important decoherence mechanisms. We show that the observed decoherence behavior can be mostly explained trough collisions of the Xe atoms with the walls. Further characterization steps in order to gain more insight in the decoherence physics involved in our MEMS cells are discussed.