Development of a neutral strontium lattice trap optical clock at the National Physical Laboratory

The ¹S₀-³P₀ transition in neutral strontium is being considered as one of the choices for the future redefinition of the SI second. At the National Physical Laboratory we are designing and implementing an optical clock based on this transition, holding the atoms in an optical lattice during the clock interrogation cycle, which greatly increases the potential accuracy of the clock. Our focus is on building a compact experimental system (including a novel permanent-magnet-based Zeeman slower) designed with the ability to assess systematic frequency shifts in mind, especially those related to blackbody radiation. Further study of systematic effects and additional intercomparisons of experimental results from different laboratories are being pursued with a view to gaining support for a future redefinition.