S
S. N. Lea
Researcher at National Physical Laboratory
Publications - 65
Citations - 2002
S. N. Lea is an academic researcher from National Physical Laboratory. The author has contributed to research in topics: Atomic clock & Frequency standard. The author has an hindex of 19, co-authored 65 publications receiving 1871 citations. Previous affiliations of S. N. Lea include École Normale Supérieure.
Papers
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Journal ArticleDOI
Frequency ratio of two optical clock transitions in 171Yb+ and constraints on the time variation of fundamental constants.
R. M. Godun,P. B. R. Nisbet-Jones,J. M. Jones,S. A. King,L. A. M. Johnson,Helen S. Margolis,Krzysztof Szymaniec,S. N. Lea,Kai Bongs,Patrick Gill +9 more
TL;DR: This work presents the first direct measurement of the frequency ratio of these two clock transitions, without reference to a cesium primary standard, and using the same single ion of 171Yb+.
Journal ArticleDOI
Hertz-level measurement of the optical clock frequency in a single 88Sr+ ion.
Helen S. Margolis,Geoffrey P. Barwood,Guilong Huang,H. A. Klein,S. N. Lea,Krzysztof Szymaniec,Patrick Gill +6 more
TL;DR: Improvements required to obtain a cesium-limited frequency measurement are described and are expected to lead to a 88Sr+ optical clock with stability and reproducibility exceeding that of the primary cedium standard.
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A cesium fountain frequency standard: preliminary results
TL;DR: In this article, the authors present a preliminary evaluation of the fountain frequency standard with a discussion of the major systematic effects which determine the expected accuracy at 10/sup -14/ level, and a description of the whole design of the cesium fountain is presented.
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Heterodyne optical phase-locking of extended-cavity semiconductor lasers at 9 GHz
TL;DR: In this paper, two extended-cavity diode lasers have been optically phase-locked at a frequency offset of 9.192 GHz to stimulate atomic velocity-selective Raman transitions on the 852 nm caesium D 2 line.
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High-resolution microwave frequency transfer over an 86-km-long optical fiber network using a mode-locked laser.
Giuseppe Marra,Radan Slavik,Helen S. Margolis,S. N. Lea,Periklis Petropoulos,David J. Richardson,Patrick Gill +6 more
TL;DR: The transfer of an ultrastable microwave frequency is demonstrated by transmitting a 30-nm-wide optical frequency comb from a mode-locked laser over 86 km of installed optical fiber.