DEVELOPMENT OF AN OPTICAL ATOMIC CLOCK BASED ON TRAPPED LUTETIUM IONS

Abstract

This thesis describes the experimental efforts towards establishing a multi-ion optical atomic clock based on singly-ionized lutetium. High-resolution spectroscopy of all relevant transitions gives hyperfine structures and reference optical frequencies for clock operation with this ion. Measurements of the polarizability for the ¹S₀-³D₁ and ¹S₀-³D₂ transitions are also described. From the results, the fractional blackbody radiation shift for ¹S₀-³D₁ transition is found to be -1.364(98)×10^-18 at 300 K, the lowest of any established optical atomic clock. Other leading systematic effects common to all ion clocks are also considered and show that both transitions compare favourably to the most accurate ion clocks reported to date. The systematic effects in a multi-ion implementation are also investigated. We demonstrate that inhomogeneous broadening effects in a small linear crystal can be suppressed to the 10^-17 level, allowing a hyperfine averaging method to practically eliminate any associated shift of the clock frequency.