An extremely stable and accurate optical lattice clock whose 17th digit can be determined in an averaging time of 15 minutes is reported online this week in Nature Photonics. The work will enable global positioning systems to detect height differences of around 10 cm in tens of minutes.
Current optical lattice clocks are limited by the Dick effect ― a source of unwanted noise associated with the laser probing scheme used to read out the frequency of the clock.
The optical lattice clock of Hidetoshi Katori and co-workers avoids this boundary, allowing it to achieve stabilities approaching the quantum projection noise limit. This work therefore represents a major step towards the practical realization of optical lattice clocks.
Nature Photonics’ April issue features additional content relating to this subject. You can access this content from March 31st onwards at http://www.nature.com/nphoton/journal/v5/n4/index.html.