Towards a Noble Gas Oscillator

Noble gas NMR detected by alkali co-magnetometers has the potential for measurement of precession frequencies at the pHz level. This is done by eliminating the dominant known sources of systematic errors: alkali frequency shifts and quadrupole shifts. We present results of successful synchronous pumping of noble gas nuclei and measurements of alkali co-magnetometer sensitivity levels that project a 131-Xe noise level of 100 $\mathrm{nHz}/\sqrt{\mathrm{Hz}}$. Future dual noble-gas co-magnetometry promises to improve the noise level by a factor of 10 or more. This research is supported by the NSF and Northrop-Grumman Corp.