Integrated physics package of micromercury trapped ion clock with [math]-level frequency stability

Applied Physics Letters, Volume 119, Issue 4, July 2021. Mercury trapped ion clocks have demonstrated great long-term frequency stability and robustness. In this paper, we report a demonstration of an integrated 100-cc physics package in an effort to develop a micromercury trapped ion clock with high frequency stability. The physics package consists of a sealed 30-cc vacuum tube with one layer of magnetic shielding, light source, and detector assembly. A field emitter array and a 194-nm microplasma lamp were employed together with a microtrap tube to reduce the size and power consumption for a mercury trapped ion clock. We show that the 100-cc physics package is capable of providing a fractional frequency stability of [math] down to [math] after a few hours of integration. We also show a set of environmental sensitivity evaluations as well as the clock frequency retrace.