Advanced lightshift compensation protocol in a continuouswave microcell atomic clock
Abstract
Lightshifts are known to be an important limitation to the mid and longterm fractional frequency stability of different types of atomic clocks. In this article, we demonstrate the experimental implementation of an advanced antilight shift interrogation protocol onto a continuouswave (CW) microcell atomic clock based on coherent population trapping (CPT). The method, inspired by the AutoBalanced Ramsey (ABR) spectroscopy technique demonstrated in pulsed atomic clocks, consists in the extraction of atomicbased information from two successive lightshifted clock frequencies obtained at two different laser power values. Two error signals, computed from the linear combination of signals acquired along a symmetric sequence, are managed in a dualloop configuration to generate a clock frequency free from lightshift. Using this method, the sensitivity of the clock frequency to both laser power and microwave power variations can be reduced by more than an order of magnitude compared to normal operation. In the present experiment, the consideration of the nonlinear lightshift dependence allowed to enhance lightshift mitigation. The implemented technique allows a clear improvement of the clock Allan deviation for time scales higher than 1000 s. This method could be applied in various kinds of atomic clocks such as CPTbased atomic clocks, doubleresonance Rb clocks, or cellstabilized lasers.
 Publication:

arXiv eprints
 Pub Date:
 May 2020
 arXiv:
 arXiv:2005.05096
 Bibcode:
 2020arXiv200505096A
 Keywords:

 Physics  Atomic Physics
 EPrint:
 9 pages with 7 figures