Dynamical decoupling of laser phase noise in compound atomic clocks
- authored by
- Sören Dörscher, Ali Al-Masoudi, Marcin Bober, Roman Schwarz, Richard Hobson, Uwe Sterr, Christian Lisdat
- Abstract
The frequency stability of many optical atomic clocks is limited by the coherence of their local oscillator. Here, we present a measurement protocol that overcomes the laser coherence limit. It relies on engineered dynamical decoupling of laser phase noise and near-synchronous interrogation of two clocks. One clock coarsely tracks the laser phase using dynamical decoupling; the other refines this estimate using a high-resolution phase measurement. While the former needs to have a high signal-to-noise ratio, the latter clock may operate with any number of particles. The protocol effectively enables minute-long Ramsey interrogation for coherence times of few seconds as provided by the current best ultrastable laser systems. We demonstrate implementation of the protocol in a realistic proof-of-principle experiment, where we interrogate for 0.5 s at a laser coherence time of 77 ms. Here, a single lattice clock is used to emulate synchronous interrogation of two separate clocks in the presence of artificial laser frequency noise. We discuss the frequency instability of a single-ion clock that would result from using the protocol for stabilisation, under these conditions and for minute-long interrogation, and find expected instabilities of σy(τ) = 8 × 10−16(τ/s)−1/2 and σy(τ) = 5 × 10−17(τ/s)−1/2, respectively.
- External Organisation(s)
-
National Metrology Institute of Germany (PTB)
IAV GmbH
Nicolaus Copernicus University
National Physical Laboratory (NPL)
- Type
- Article
- Journal
- Communications Physics
- Volume
- 3
- Publication date
- 01.12.2020
- Publication status
- Published
- Peer reviewed
- Yes
- ASJC Scopus subject areas
- Physics and Astronomy(all)
- Electronic version(s)
-
https://doi.org/10.1038/s42005-020-00452-9 (Access:
Open)