Towards a compact, optically interrogated, cold-atom microwave clock

摘要

A compact platform for cold atoms opens a range of exciting possibilities for portable, robust and accessible quantum sensors. In this work, we report on the development of a cold-atom microwave clock in a small package. Our work utilises the grating magneto-optical trap and high-contrast coherent population trapping in the limain polarisation scheme. We optically probe the atomic ground-state splitting of cold Rb-87 atoms using a Ramsey-like sequence whilst the atoms are in free-fall. We have measured a short-term fractional frequency stability of 5 x 10(-11)/root tau with a projected quantum projection noise limit at the 10(-13)/root tau level.