Progress towards development of a trapped strontium ion space optical clock

Abstract

Optical clocks can now achieve a higher stability and lower systematic uncertainty than the highest performance microwave atomic clocks. For a Trapped Ion Space Optical Clock (TISOC) project funded by the European Space Agency (ESA) we are developing an optical clock based on a trapped laser-cooled strontium ion for future deployment in space. In a laboratory setting, a ⁸⁸Sr⁺ system has been shown to provide excellent performance and crucially has reduced size, mass, laser power and complexity compared to alternatives such as lattice clocks. Spaceborne optical atomic clocks will offer transformative capabilities for future science, navigation, and earth observation programmes. As a first step towards space deployment, the design used in our existing single ion clocks was employed as a baseline to develop a set of finite element models. These were used to simulate the response of the ion trap and accompanying vacuum chamber to vibration, shock and thermal conditions encountered during launch and space deployment. Additionally, an electrostatic model has been developed to investigate the relationship between the ion trap geometrical tolerances and the trapping efficiency. We present the results from these analyses and how they have helped design a more robust prototype for experimental testing.