Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Ultra-high contrast coherent population trapping resonances in a cold-atom microwave clock

Published

Author(s)

Xiaochi Liu, V. I. Yudin, A. V. Taichenachev, John E. Kitching, Elizabeth A. Donley

Abstract

A cold-atom coherent population trapping clock can achieve a better long-term frequency stability than similar clocks based on vapor cells, since long interrogation periods are possible without introducing systematic frequency shifts from buffer gases. Here we demonstrate a cold-atom CPT clock based on ς+–ς-; interrogation realized by counter-propagating optical fields of opposite circular polarization. Because the system is based on cold atoms and there is very little relaxation, nearly complete dark states are created and CPT resonances with maximum contrast are observed. A fractional frequency stability of 1.3×^-11/√τ is achieved, which averages down to 2×10^-13 after a 40,000 s integration period.
Citation
Applied Physics Letters

Keywords

atomic clock, coherent population trapping, light shifts, ramsey spectroscopy

Citation

Liu, X. , Yudin, V. , Taichenachev, A. , Kitching, J. and Donley, E. (2017), Ultra-high contrast coherent population trapping resonances in a cold-atom microwave clock, Applied Physics Letters, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=923695 (Accessed September 17, 2021)
Created November 29, 2017, Updated January 29, 2018