Using tensor light shifts to measure and cancel a cell's quadrupolar frequency shift

Abstract

We have developed a technique that uses the tensor light shift to measure and cancel the frequency shift produced by the quadrupolar anisotropy of a vapor cell. We demonstrate the technique on the $6{S}_{1/2},\phantom{\rule{0.16em}{0ex}}F=4$ level of Cs using the ${D}_{1}$ transition. The method extends our ability to study quadrupolar wall interactions beyond diamagnetic atoms. We have deduced the twist angle per wall adhesion for cesium on an alkene coating to be ${\ensuremath{\theta}}_{\mathrm{Cs}\ensuremath{-}\mathrm{alkene}}=1.4\phantom{\rule{4pt}{0ex}}\mathrm{mrad}$. This value is about 37 times larger than the twist angle observed in $^{131}\text{Xe}$, suggesting that it is not produced by the interaction of the nuclear quadrupole moment with a collisional electric-field gradient. Alternative mechanisms that may be responsible for the observed quadrupolar frequency shifts are discussed. By canceling the cell-induced quadrupole shift we have extended our cells' effective spin-relaxation times by as much as a factor of 2. This cancellation improves magnetometer sensitivity in highly anisotropic cells and could reduce systematic uncertainties in some precision measurements.