How to build a magnetometer with thermal atomic vapor: a tutorial

Abstract

This article is designed as a step-by-step guide to optically pumped magnetometers based on alkali atomic vapor cells. We begin with a general introduction to atomic magneto-optical response, as well as expected magnetometer performance merits and how they are affected by main sources of noise. This is followed by a brief comparison of different magnetometer realizations and an overview of current research, with the aim of helping readers to identify the most suitable magnetometer type for specific applications. Next, we discuss some practical considerations for experimental implementations, using the case of an M z magnetometer as an example of the design process. Finally, an interactive workbook with real magnetometer data is provided to illustrate magnetometer-performance analysis.

Proton Relaxometry of Tree Leaves at Hypogeomagnetic Fields

“…Relaxation-dispersion studies (measuring relaxation times as a function of field) may also reveal further information about water-storing structures [36, 37, 38]. Instrumentation such as custom magnetometers tailored to plant samples—with reduced standoff distance and surface temperature—will improve biocompatibility, and the use of Earth-field magnetometers would even enable unshielded measurements (see [39] and references therein). The shielded regime is itself of fundamental interest, for example in studying properties of biological tissues under hypogeomagnetic conditions such as those encountered during long-distance spaceflight.…”

“…Relaxation-dispersion studies (measuring relaxation times as a function of field) may also reveal further information about water-storing structures [36,37,38]. Instrumentation such as custom magnetometers tailored to plant samples-with reduced standoff distance and surface temperature-will improve biocompatibility, and the use of Earthfield magnetometers would even enable unshielded measurements (see [39] and references therein).…”

Speedy in-situ magnetic field compensation algorithm for multiple-channel single-beam SERF atomic magnetometers

“…The frequency ω m is (900-1100) Hz as usual. The derivative of the Lorentzian curve is generated when the signal from the photodetector is demodulated using a lock-in amplifier (LIA) [28]. Internally, the LIA at a given reference frequency, which should be the same as ω m .…”

Spatially-dependent dark states in cold atomic vapours

“…Other versions may observe the coherent Larmor precessions the atoms exhibit in a magnetic field, or, in the case of vector magnetometers, map the vector components onto different harmonics using radio-frequency modulation. 21 Electromagnetically induced transparency (EIT) is created by pumping the atoms into a dark state with a pump beam, leaving them unable to absorb an otherwise resonant probe beam, and hence transparent. Using vector light composed of different linear polarisations, the circular components act as both pump and probe simultaneously, and dependent on their phase, or the linear polarisation direction, EIT can or cannot be observed.…”