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\nIn the prese nt work\, I have demonstrated an optically pumped scalar magnetometer using a 1 cm diameter by 1 cm length internal dimension cylindrical va por cell with a photon shot noise limit of 3.5 $fT/\\sqrt{Hz}$ and a d emonstrated single-channel noise of 10 $fT/\\sqrt{Hz}$ as limited by t he electrical current source generating a 29 $\\mu T$ bias field. I ha ve further demonstrated a differential pair of these magnetometers\, s eparated by a distance of 9 cm\, with measured differential noise of 1 $fT cm^{-1}/\\sqrt{Hz}$\, consistent with a single-channel noise of 6 $fT/\\sqrt{Hz}$. I present a straightforward procedure for optimizati on of the sensitivity of this magnetometer to achieve fundamental sens itivity limits in the low single digit $fT/\\sqrt{Hz}$ and guidelines for detection electronics supporting total noise from the magnetometer dominated by the fundamental sensitivity limit. I demonstrate\, analy ze\, and characterise the basis of a method for detection of the vecto r components of the incident magnetic field through the use of an appl ied oscillating field along each vector axis to be measured\, and I pr esent initial results with single-axis vector component detection. Inc luded in the relevant chapter are algorithms and feedback methods for achieving high performance\, along with a demonstration of each\, and measurements of performance including relative accuracy and uncertaint y. I further present a demonstration and theory of detection of RF mag netic fields near the natural Larmor precession frequency of the spins \, taking advantage of the AC Stark shift of the optical pump beam to generate a linear sensitivity to the RF signal\, measured at the diffe rence between the RF frequency and Larmor frequency. Finally\, I look toward future work\, proposing a method for measurement of the vector direction of the incident magnetic field by real-time observation of t he spin precession. URL:https://www.physics.wisc.edu/events/?id=8384 END:VEVENT END:VCALENDAR