Characteristics and performance of an intensity-modulated optically pumped magnetometer in comparison to the classical M_x magnetometer

Abstract

We compare the performance of two methods for the synchronization of the atomic spins in optically pumped magnetometers: intensity modulation of the pump light and the classical M(x) method using B(1) field modulation. Both techniques use the same set-up and measure the resulting features of the light after passing a micro-fabricated Cs cell. The intensity-modulated pumping shows several advantages: better noise-limited magnetic field sensitivity, misalignment between pumping and spin synchronization is excluded, and magnetometer arrays without any cross-talk can be easily set up.

Magneto-optic spectroscopy with linearly polarized modulated light: Theory and experiment

“…. , 5), are real or complex conjugate couples. The λ k have a negative real part, and thus the initial conditions in the right-hand side of Eq.…”

“…Replacing spectral lamps with lasers allowed studying new approaches based on the modulation of light parameters that was in the past limited to amplitude modulation [3]. Relevant contributions in frequency-and amplitude-modulation spectroscopy comes from different groups [4][5][6][7]. In recent years atomic magnetometers [8] have become valuable tools not only in general physics [9], but also in exotic applications like detection of magnetic particles [10], and ultra-low-field NMR [11,12], etc.…”

Studies of AM He Atomic Magnetometer for Fusion Plasmas

“…4. This test magnetic field is perpendicular to a beam direction, which maximizes resonant signals [4].…”

“…An atomic magnetometer, in particular, amplitude modulated helium atomic magnetometer (AM He AOM) allows spatially resolved magnetic field measurements even in the inner regions of burning plasmas, where helium ions are produced from the D-T fusion reaction and part of them exist as meta stable 4 He (2 3 S 1 ) atoms suggested as probing targets in this work. Accordingly neither heating beam nor impurity atoms is necessary.…”

A Bell-Bloom experiment with polarization-modulated light of arbitrary duty cycle

“…Using, on the other hand, a square wave intensity modulation that contains all harmonics of the fundamental frequency ω mod will lead to a richer spectrum in which resonances occur at ω L = ± m ω mod . In recent years, phase-sensitive detection was used to record such amplitude-modulation resonance spectra with an improved signal/noise ratio (compared to Bell and Bloom's low-pass filtered detection), either by direct lock-in detection of the transmitted power [2] or in combination with polarization analysis [3].…”