Heading-Error-Free Optical Atomic Magnetometry in the Earth-Field Range
Rui Zhang, Dimitra Kanta, Arne Wickenbrock, Hong Guo, Dmitry Budker
Abstract
We demonstrate an alignment-based $^{87}\mathrm{Rb}$ magnetometer that is immune to nonlinear Zeeman (NLZ) splitting, addressing an important problem in alkali-metal atomic magnetometry. In our scheme, there is a single magnetic resonance peak and well-separated hyperfine transition frequencies, making the magnetometer insensitive or even immune to NLZ-related heading errors. It is shown that the magnetometer can be implemented for practical measurements in geomagnetic environments, and the photon-shot-noise-limited sensitivity reaches $9\text{ }\text{ }\mathrm{fT}/\sqrt{\mathrm{Hz}}$ at $5\text{ }\text{ }\mathrm{\ensuremath{\mu}}\mathrm{T}$ and remains at tens of $\mathrm{fT}/\sqrt{\mathrm{Hz}}$ at $50\text{ }\text{ }\mathrm{\ensuremath{\mu}}\mathrm{T}$ at room temperature.