Double-Modulation Coherent Population Trapping Clock

Atomic clocks based on coherent population trapping and constructive polarization modulation are promising for high performance and compact devices. We have demonstrated a cw mode CPT clock with a short-term fractional frequency stability at the level of 3. \pmb2×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-13</sup> /√{τ} for a few 100 s integration time. This Double-Modulation CPT technology can be reduced to a miniature and robust setup due to its linear architecture. This clock could find future applications in industry, telecommunications, instrumentation, or global navigation satellite systems.