Dead-zone-free single-beam atomic magnetometer based on free-induction-decay of Rb atoms

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Main Authors: Mehta, Shrey, Samanta, G. K., Grewal, Raghwinder Singh
Format: Preprint
Published: 2024
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author Mehta, Shrey
Samanta, G. K.
Grewal, Raghwinder Singh
author_facet Mehta, Shrey
Samanta, G. K.
Grewal, Raghwinder Singh
contents Free-induction-decay (FID) magnetometers have evolved as simple magnetic sensors for sensitive detection of unknown magnetic fields. However, these magnetometers suffer from a fundamental problem known as a "dead zone," making them insensitive to certain magnetic field directions. Here, we demonstrate a simple experimental scheme for the dead-zone-free operation of a FID atomic magnetometer. Using a single laser beam containing equal strength of linear- and circular-polarization components and amplitude-modulation at a low-duty cycle, we have synchronously pumped the rubidium-87 atoms with both first- and second-order frequency harmonics. Such a pumping scheme has enabled us to observe the free Larmor precession of atomic spins at a frequency of $Ω_L$ (orientation) and/or 2$Ω_L$ (alignment) in a single FID signal, depending on the direction of the external magnetic field. We observed that the amplitude of the FID signal does not go to zero for any magnetic field direction, proving the absence of dead zones in the magnetometer. The magnetometer has a sensitivity in the range of 3.2 - 8.4 pT/$\sqrt{Hz}$ in all directions. Our experimental scheme can be crucial in developing miniaturized atomic magnetometers for various practical applications, including geomagnetic applications.
format Preprint
id arxiv_https___arxiv_org_abs_2410_15663
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Dead-zone-free single-beam atomic magnetometer based on free-induction-decay of Rb atoms
Mehta, Shrey
Samanta, G. K.
Grewal, Raghwinder Singh
Atomic Physics
Free-induction-decay (FID) magnetometers have evolved as simple magnetic sensors for sensitive detection of unknown magnetic fields. However, these magnetometers suffer from a fundamental problem known as a "dead zone," making them insensitive to certain magnetic field directions. Here, we demonstrate a simple experimental scheme for the dead-zone-free operation of a FID atomic magnetometer. Using a single laser beam containing equal strength of linear- and circular-polarization components and amplitude-modulation at a low-duty cycle, we have synchronously pumped the rubidium-87 atoms with both first- and second-order frequency harmonics. Such a pumping scheme has enabled us to observe the free Larmor precession of atomic spins at a frequency of $Ω_L$ (orientation) and/or 2$Ω_L$ (alignment) in a single FID signal, depending on the direction of the external magnetic field. We observed that the amplitude of the FID signal does not go to zero for any magnetic field direction, proving the absence of dead zones in the magnetometer. The magnetometer has a sensitivity in the range of 3.2 - 8.4 pT/$\sqrt{Hz}$ in all directions. Our experimental scheme can be crucial in developing miniaturized atomic magnetometers for various practical applications, including geomagnetic applications.
title Dead-zone-free single-beam atomic magnetometer based on free-induction-decay of Rb atoms
topic Atomic Physics
url https://arxiv.org/abs/2410.15663