Ian Hill

Ben Sauer

The development of extremely precise and accurate optical lattice clocks has revolutionized the landscape of quantum metrology, leading to orders of magnitude improvement in the performance of atomic frequency standards since their first microwave realization in the mid-1950s at the National Physical Laboratory (NPL). In addition to finding immediate industrial applications in high precision time and frequency metrology, optical clocks have also spurred exciting research opportunities in disparate fields of research such as the hunt for the evidence of dark matter, tests of Lorentz invariance, and the probe for variations in fundamental constants. Today, optical lattice clocks with fractional frequency instabilities as low as the 18th decimal place have been developed in several research groups across the globe, and with performances already surpassing those of the caesium primary frequency standards, further developments may very well lead to the redefinition of the second based on an optical transition.

 In this project, we focus on the development of the two strontium (Sr) optical lattice clocks present at the NPL, with the goal of achieving fractional frequency instabilities at the 10-18 level and below. At the same time, we couple this effort to a more general study of quantum-engineered optical interrogation methods to further minimise perturbations in the transition frequency of Sr optical lattice clocks. Continuous work will be done towards the minimization of the uncertainty budgets of the two clocks by improving the characterization of environmental and experimentally-induced noise on the clock transition frequency. We also aim to develop a fully operational zero dead-time (ZDT) clock whose instability would be limited only by quantum projection noise (QPN). It will then be possible to develop new techniques to overcome QPN and achieve unprecedented levels of stability.