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Helium-4 magnetometers for room-temperature biomedical imaging: toward collective operation and photon-noise limited sensitivity.
- Source :
-
Optics express [Opt Express] 2021 May 10; Vol. 29 (10), pp. 14467-14475. - Publication Year :
- 2021
-
Abstract
- Optically-pumped magnetometers constitute a valuable tool for imaging biological magnetic signals without cryogenic cooling. Nowadays, numerous developments are being pursued using alkali-based magnetometers, which have demonstrated excellent sensitivities in the spin-exchange relaxation free (SERF) regime that requires heating to >100 °C. In contrast, metastable helium-4 based magnetometers work at any temperature, which allows a direct contact with the scalp, yielding larger signals and a better patient comfort. However former <superscript>4</superscript> He magnetometers displayed large noises of >200 fT/Hz <superscript>1/2</superscript> with 300-Hz bandwidth. We describe here an improved magnetometer reaching a sensitivity better than 50 fT/Hz <superscript>1/2</superscript> , nearly the photon shot noise limit, with a bandwidth of 2 kHz. Like other zero-field atomic magnetometers, these magnetometers can be operated in closed-loop architecture reaching several hundredths nT of dynamic range. A small array of 4 magnetometers operating in a closed loop has been tested with a successful correction of the cross-talks.
Details
- Language :
- English
- ISSN :
- 1094-4087
- Volume :
- 29
- Issue :
- 10
- Database :
- MEDLINE
- Journal :
- Optics express
- Publication Type :
- Academic Journal
- Accession number :
- 33985169
- Full Text :
- https://doi.org/10.1364/OE.420031