ROCIT: Optical clocks for the redefinition of the SI second


ROCIT_logo.jpg2019–2022    Steps towards an optical redefinition of the SI second

A future redefinition of the second is anticipated as optical atomic clocks have overtaken caesium clocks in terms of fractional frequency instability and estimated systematic uncertainty. However, no optical clock has yet contributed to the TAI.

Project brings optical clocks to the point where they can contribute regularly to the international timescales. This is a prerequisite for redefinition of the second in terms of an optical frequency.ROCIT.png

Project actions:
WP1: Robust optical clocks with on-the-fly systematic shift correction
WP2: International optical clock comparisons
WP3: Incorporating optical clocks into UTC(k) timescales
WP4: Optical clocks as secondary representations of the second

VTT MIKES develops a Sr+ optical clock and contributes to clock comparisons via GPS PPP links.

More information: Thomas Lindvall, tel. +358 50 443 4108

Project website: