A grating-chip atomic fountain

Cold atom fountain clocks provide exceptional long term stability as they increase interrogation time at the expense of a larger size. We present a compact cold atom fountain using a grating magneto-optical trap to laser cool and launch the atoms in a simplified optical setup. The fountain is evaluated using coherent population trapping and demonstrates improved single-shot stability from the launch. Ramsey times up to 100 ms were measured with a corresponding fringe linewidth of 5 Hz. This technique could improve both short- and long-term stabilities of cold atom clocks while remaining compact for portable applications. (C) 2022 Author(s).