Long spin-1/2 noble gas coherence times in mm-sized anodically bonded batch-fabricated $^{3}$He-$^{129}$Xe-$^{87}$Rb cells

TL;DR

This paper reports the development of anodically bonded, batch-fabricated microcells containing $^{3}$He, $^{129}$Xe, and $^{87}$Rb, achieving unprecedented coherence times for noble gases in miniature cells, enabling advanced inertial sensing and fundamental physics experiments.

Contribution

First demonstration of anodically bonded batch-fabricated microcells with dual noble gases and alkali metal, achieving hours-long coherence times in 6 mm$^3$ volume.

Findings

$^{3}$He $T_2$ coherence time of 4 hours

$^{129}$Xe $T_2$ coherence time of 300 seconds

Successful operation of dual noble-gas comagnetometer

Abstract

As the only stable spin-1/2 noble gas isotopes, $^{3}$He and $^{129}$Xe are promising systems for inertial rotation sensing and searches for exotic spin couplings. Spin-1/2 noble gases have intrinsic coherence times on the order of hours to days, which allows for incredibly low frequency error of free-precession measurements. However relaxation in miniature cells is dominated by interactions with the cell wall, which limits the performance of a chip-scale sensor that uses noble gases. While $^{129}$Xe wall relaxation times have previously been limited to 10's of seconds in mm-sized cells, we demonstrate the first anodically bonded batch-fabricated cells with dual $^{3}$He-$^{129}$Xe isotopes and $^{87}$Rb in a 6~mm$^3$ volume with $^{3}$He and $^{129}$Xe $T_2$ coherence times of, respectively, 4 h and 300 s. We use these microfabricated cells in a dual noble-gas comagnetometer and discuss its limits.