The design of a Λ-HFS magnetometer

Abstract

The design of a new quantum magnetometer for geomagnetic fields, an outgrowth of the idea of the so-called HFS magnetometer that uses microwave transitions between hyperfine sublevels of alkaline atoms, is presented. In contrast to the ordinary HFS magnetometer, which measures the frequency difference of two independent transitions, the new Λ-HFS magnetometer is based on the excitation of two transitions with a common level. The design under discussion retains the principal advantages of the prototype (negligible systematic errors and the absence of dead zones for a single sensor), with the electronic circuits being simplified significantly and the requirements on the short-term frequency stability of the reference oscillator being relaxed substantially. An analysis of the new scheme is based on the solution of the equation for the density matrix of a multilevel system without constraints on the power of the microwave fields.