title: Non-invasive detection of animal nerve impulses with an atomic magnetometer operating near quantum limited sensitivity.
abstract: Magnetic fields generated by human and animal organs, such as the heart, brain and nervous system carry information useful for biological and medical purposes. These magnetic fields are most commonly detected using cryogenically-cooled superconducting magnetometers. Here we present the first detection of action potentials from an animal nerve using an optical atomic magnetometer. Using an optimal design we are able to achieve the sensitivity dominated by the quantum shot noise of light and quantum projection noise of atomic spins. Such sensitivity allows us to measure the nerve impulse with a miniature room-temperature sensor which is a critical advantage for biomedical applications. Positioning the sensor at a distance of a few millimeters from the nerve, corresponding to the distance between the skin and nerves in biological studies, we detect the magnetic field generated by an action potential of a frog sciatic nerve. From the magnetic field measurements we determine the activity of the nerve and the temporal shape of the nerve impulse. This work opens new ways towards implementing optical magnetometers as practical devices for medical diagnostics.
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark.
authors.forename: Kasper
authors.initials: K
authors.lastname: Jensen
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark.
authors.forename: Rima
authors.initials: R
authors.lastname: Budvytyte
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark.
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Thomas
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark.
authors.forename: Tian
authors.initials: T
authors.lastname: Wang
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark.
authors.forename: Annette M
authors.initials: AM
authors.lastname: Fuchs
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark.|Department of Physics, St Petersburg State University, Universitetskii pr. 28, 198504 Staryi Peterhof, Russia.
authors.forename: Mikhail V
authors.initials: MV
authors.lastname: Balabas
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark.
authors.forename: Georgios
authors.initials: G
authors.lastname: Vasilakis
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark.
authors.forename: Lars D
authors.initials: LD
authors.lastname: Mosgaard
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark.
authors.forename: Hans C
authors.initials: HC
authors.lastname: Stærkind
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark.
authors.forename: Jörg H
authors.initials: JH
authors.lastname: Müller
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Heimburg
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark.
authors.forename: Søren-Peter
authors.initials: SP
authors.lastname: Olesen
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark.
authors.forename: Eugene S
authors.initials: ES
authors.lastname: Polzik
mesh_terms: D000200:Action Potentials; D000818:Animals; D001001:Anura / Q000502:physiology*; D008280:Magnetics / Q000295:instrumentation*; D045663:Quantum Dots; D012584:Sciatic Nerve / Q000502:physiology*