A Feedback-Compensated Synchronous Coherent Population Trapping Based Vector Magnetometer

We have developed a feedback-compensated vector magnetometer using the phenomenon, called synchronous coherent population trapping (SCPT) in a small rubidium vapor cell. SCPT gives the advantage of producing a high contrast and narrow linewidth resonance needed for measuring magnetic field with high sensitivity. The feedback mechanism enables vector operation in our magnetometer, by performing a peak-lock on the SCPT resonance and compensating the external magnetic field via a three-axis field coil. We have demonstrated accurate vector magnetic measurements by using our sensor in a fully-shielded environment and have also conducted field tests in a partially-shielded environment. Further developments are undertaken to design a high-performance field-deployable sensor prototype that can used to perform long-term measurement and tracking of earth's field with high accuracy and high sensitivity.