Dipolar and scalar $^3$He and $^{129}$Xe frequency shifts in mm-sized cells

TL;DR

This study develops a $^{3}$He-$^{129}$Xe comagnetometer with optimized cell geometry, revealing how shape influences frequency shifts and demonstrating a scalar collisional shift with a specific enhancement factor.

Contribution

It introduces a method to control cell shape effects in vapor-cell comagnetometers and measures the first scalar $^{3}$He-$^{129}$Xe collisional frequency shift.

Findings

Cell aspect ratio can cancel $^3$He magnetization effects.

First measurement of scalar $^{3}$He-$^{129}$Xe collisional frequency shift.

Achieved $^{129}$Xe spin coherence time of 300 seconds.

Abstract

We describe a $^{3}$He-$^{129}$Xe comagnetometer operating in stemless anodically bonded cells with a 6 mm$^3$ volume and a $^{129}$Xe spin coherence time of 300 sec. We use a $^{87}$Rb pulse-train magnetometer with co-linear pump and probe beams to study the nuclear spin frequency shifts caused by spin polarization of $^{3}$He. By systematically varying the cell geometry in a batch cell fabrication process we can separately measure the cell shape dependent and independent frequency shifts. We find that a certain aspect ratio of the cylindrical cell can cancel the effects of $^3$He magnetization that limit the stability of vapor-cell comagnetometers. Using this control we also observe for the first time a scalar $^{3}$He-$^{129}$Xe collisional frequency shift characterized by an enhancement factor $\kappa_{\text{HeXe}} = -0.011\pm0.001$.