High-Sensitivity Atomic Magnetometer Unaffected by Spin-Exchange Relaxation

J. C. Allred, R. N. Lyman, T. W. Kornack, and M. V. Romalis
Phys. Rev. Lett. 89, 130801 – Published 9 September 2002

Abstract

Alkali-metal magnetometers compete with SQUID detectors as the most sensitive magnetic field sensors. Their sensitivity is limited by relaxation due to spin-exchange collisions. We demonstrate a K magnetometer in which spin-exchange relaxation is completely eliminated by operating at high K density and low magnetic field. Direct measurements of the signal-to-noise ratio give a magnetometer sensitivity of 10   fTHz1/2, limited by magnetic noise produced by Johnson currents in the magnetic shields. We extend a previous theoretical analysis of spin exchange in low magnetic fields to arbitrary spin polarizations and estimate the shot-noise limit of the magnetometer to be 2×1018   T   Hz1/2.

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  • Received 6 March 2002

DOI:https://doi.org/10.1103/PhysRevLett.89.130801

©2002 American Physical Society

Authors & Affiliations

J. C. Allred and R. N. Lyman

  • Department of Physics, Univerisity of Washington, Seattle, Washington 98195

T. W. Kornack and M. V. Romalis*

  • Department of Physics, Princeton University, Princeton, New Jersey 08544

  • *Author to whom correspondence should be addressed: romalis@princeton.edu

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Issue

Vol. 89, Iss. 13 — 23 September 2002

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