Abstract

In the field of biomagnetic measurement, optically-pumped atomic magnetometers (OPAMs) have attracted significant attention. With the improvement of signal response and the reduction of sensor noise, the sensitivity of OPAMs is limited mainly by environmental magnetic noise. To reduce this magnetic noise, we developed the optical gradiometer, in which the differential output of two distinct measurement areas inside a glass cell was obtained directly via the magneto-optical rotation of one probe beam. When operating in appropriate conditions, the sensitivity was improved by the differential measurement of the optical gradiometer. In addition, measurements of the pseudo-magnetic noise and signal showed the improvement of the signal-to-noise ratio. These results demonstrate the feasibility of our optical gradiometer as an efficient method for reducing the magnetic noise.

© 2015 Optical Society of America

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References

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    [Crossref]

2015 (1)

K. Kamada, D. Sato, Y. Ito, H. Natsukawa, K. Okano, N. Mizutani, and T. Kobayashi, “Human magnetoencephalogram measurements using a newly developed compact module of high-sensitivity atomic magnetometer,” Jpn. J. Appl. Phys. 54, 026601 (2015).
[Crossref]

2014 (3)

2013 (2)

C. N. Johnson, P. D. D. Schwindt, and M. Weisend, “Multi-sensor magnetoencephalography with atomic magnetometers,” Phys. Med. Biol. 58, 6065–6077 (2013).
[Crossref] [PubMed]

V. K. Shah and R. T. Wakai, “A compact, high performance atomic magnetometer for biomedical applications,” Phys. Med. Biol. 58, 8153–8161 (2013).
[Crossref] [PubMed]

2012 (3)

K. Kamada, Y. Ito, and T. Kobayashi, “Human MCG measurements with a high-sensitivity potassium atomic magnetometer,” Physiol. Meas. 33, 1063–1071 (2012).
[Crossref] [PubMed]

R. Wyllie, M. Kauer, R. T. Wakai, and T. G. Walker, “Optical magnetometer array for fetal magnetocardiography,” Opt. Lett. 37, 2247–2249 (2012).
[Crossref] [PubMed]

Y. Ito, H. Ohnishi, K. Kamada, and T. Kobayashi, “Effect of spatial homogeneity of spin polarization on magnetic field response of an optically pumped atomic magnetometer using a hybrid cell of K and Rb atoms,” IEEE Trans. Magn. 48, 3715–3718 (2012).
[Crossref]

2011 (2)

K. Kamada, S. Taue, and T. Kobayashi, “Optimization of bandwidth and signal responses of optically pumped atomic magnetometers for biomagnetic applications,” Jpn. J. Appl. Phys. 50, 056602 (2011).
[Crossref]

Y. Ito, H. Ohnishi, K. Kamada, and T. Kobayashi, “Sensitivity improvement of spin-exchange relaxation free atomic magnetometers by hybrid optical pumping of potassium and rubidium,” IEEE Trans. Magn. 47, 3550–3553 (2011).
[Crossref]

2010 (1)

S. Knappe, T. H. Sander, O. Kosch, F. Wiekhorst, J. Kitching, and L. Trahms, “Cross-validation of microfabricated atomic magnetometers with superconducting quantum interference devices for biomagnetic applications,” Appl. Phys. Lett. 97, 133703 (2010).
[Crossref]

2008 (1)

M. P. Ledbetter, I. M. Savukov, V. M. Acosta, D. Budker, and M. V. Romalis, “Spin-exchange-relaxation-free magnetometry with Cs vapor,” Phys. Rev. A 77, 033408 (2008).
[Crossref]

2007 (1)

D. Budker and M. V. Romalis, “Optical magnetometry,” Nat. Phys. 3, 227–234 (2007).
[Crossref]

2006 (3)

S. Groeger, G. Bison, J. L. Schenker, R. Wynands, and A. Weis, “A high-sensitivity laser-pumped Mx magnetometer,” Eur. Phys. J. D 38, 239–247 (2006).
[Crossref]

H. Xia, A. B. A. Baranga, D. Hoffman, and M. V. Romalis, “Magnetoencephalography with an atomic magnetometer,” Appl. Phys. Lett. 89, 211104 (2006).
[Crossref]

S. Xu, V. V. Yashchuk, M. H. Donaldson, S. M. Rochester, D. Budker, and A. Pines, “Magnetic resonance imaging with an optical atomic magnetometer,” Proc. Natl. Acad. Sci. USA 103, 12668–12671 (2006).
[Crossref] [PubMed]

2005 (2)

I. M. Savukov and M. V. Romalis, “Effects of spin-exchange collisions in a high-density alkali-metal vapor in low magnetic fields,” Phys. Rev. A 71, 023405 (2005).
[Crossref]

I. M. Savukov, S. J. Seltzer, M. V. Romalis, and K. L. Sauer, “Tunable atomic magnetometer for detection of radio-frequency magnetic fields,” Phys. Rev. Lett. 95, 063004 (2005).
[Crossref] [PubMed]

2003 (2)

G. Bison, R. Wynands, and A. Weis, “Dynamical mapping of the human cardiomagnetic field with a room-temperature, laser-optical sensor,” Opt. Express 11, 904–909 (2003).
[Crossref] [PubMed]

I. K. Kominis, T. W. Kornack, J. C. Allred, and M. V. Romalis, “A subfemtotesla multichannel atomic magnetometer,” Nature 422, 596–599 (2003).
[Crossref] [PubMed]

2002 (1)

J. C. Allred, R. N. Lyman, T. W. Kornack, and M. V. Romalis, “High-sensitivity atomic magnetometer unaffected by spin-exchange relaxation,” Phys. Rev. Lett. 89, 130801 (2002).
[Crossref] [PubMed]

2001 (1)

H. Koch, “SQUID magnetocardiography: status and perspectives,” IEEE Trans. Appl. Supercond. 11, 49–59 (2001).
[Crossref]

1999 (1)

A. Garachtchenko, A. Matlashov, R. H. Kraus, and R. Cantor, “Baseline distance optimization for SQUID gradiometers,” IEEE Trans. Appl. Supercond. 9, 3676–3679 (1999).
[Crossref]

1998 (1)

S. Appelt, A. B. A. Baranga, C. J. Erickson, M. V. Romalis, A. R. Young, and W. Happer, “Theory of spin-exchange optical pumping of 3He and 129Xe,” Phys. Rev. A 58, 1412–1439 (1998).
[Crossref]

1993 (1)

M. Hämäläinen, R. Hari, R. Ilmoniemi, J. Knuutila, and O. V. Lounasmaa, “Magnetoencephalography: theory, instrumentation, and applications to noninvasive studies of the working human brain,” Rev. Mod. Phys. 65, 413–497 (1993).
[Crossref]

1973 (1)

W. Happer and H. Tang, “Spin-exchange shift and narrowing of magnetic resonance lines in optically pumped alkali vapors,” Phys. Rev. Lett. 31, 273–276 (1973).
[Crossref]

Acosta, V. M.

M. P. Ledbetter, I. M. Savukov, V. M. Acosta, D. Budker, and M. V. Romalis, “Spin-exchange-relaxation-free magnetometry with Cs vapor,” Phys. Rev. A 77, 033408 (2008).
[Crossref]

Allred, J. C.

I. K. Kominis, T. W. Kornack, J. C. Allred, and M. V. Romalis, “A subfemtotesla multichannel atomic magnetometer,” Nature 422, 596–599 (2003).
[Crossref] [PubMed]

J. C. Allred, R. N. Lyman, T. W. Kornack, and M. V. Romalis, “High-sensitivity atomic magnetometer unaffected by spin-exchange relaxation,” Phys. Rev. Lett. 89, 130801 (2002).
[Crossref] [PubMed]

Appelt, S.

S. Appelt, A. B. A. Baranga, C. J. Erickson, M. V. Romalis, A. R. Young, and W. Happer, “Theory of spin-exchange optical pumping of 3He and 129Xe,” Phys. Rev. A 58, 1412–1439 (1998).
[Crossref]

Ban, K.

N. Mizutani, K. Okano, K. Ban, S. Ichihara, A. Terao, and T. Kobayashi, “A plateau in the sensitivity of a compact optically pumped atomic magnetometer,” AIP Adv. 4, 057132 (2014).
[Crossref]

Baranga, A. B. A.

H. Xia, A. B. A. Baranga, D. Hoffman, and M. V. Romalis, “Magnetoencephalography with an atomic magnetometer,” Appl. Phys. Lett. 89, 211104 (2006).
[Crossref]

S. Appelt, A. B. A. Baranga, C. J. Erickson, M. V. Romalis, A. R. Young, and W. Happer, “Theory of spin-exchange optical pumping of 3He and 129Xe,” Phys. Rev. A 58, 1412–1439 (1998).
[Crossref]

Bison, G.

S. Groeger, G. Bison, J. L. Schenker, R. Wynands, and A. Weis, “A high-sensitivity laser-pumped Mx magnetometer,” Eur. Phys. J. D 38, 239–247 (2006).
[Crossref]

G. Bison, R. Wynands, and A. Weis, “Dynamical mapping of the human cardiomagnetic field with a room-temperature, laser-optical sensor,” Opt. Express 11, 904–909 (2003).
[Crossref] [PubMed]

Budker, D.

M. P. Ledbetter, I. M. Savukov, V. M. Acosta, D. Budker, and M. V. Romalis, “Spin-exchange-relaxation-free magnetometry with Cs vapor,” Phys. Rev. A 77, 033408 (2008).
[Crossref]

D. Budker and M. V. Romalis, “Optical magnetometry,” Nat. Phys. 3, 227–234 (2007).
[Crossref]

S. Xu, V. V. Yashchuk, M. H. Donaldson, S. M. Rochester, D. Budker, and A. Pines, “Magnetic resonance imaging with an optical atomic magnetometer,” Proc. Natl. Acad. Sci. USA 103, 12668–12671 (2006).
[Crossref] [PubMed]

Cantor, R.

A. Garachtchenko, A. Matlashov, R. H. Kraus, and R. Cantor, “Baseline distance optimization for SQUID gradiometers,” IEEE Trans. Appl. Supercond. 9, 3676–3679 (1999).
[Crossref]

Donaldson, M. H.

S. Xu, V. V. Yashchuk, M. H. Donaldson, S. M. Rochester, D. Budker, and A. Pines, “Magnetic resonance imaging with an optical atomic magnetometer,” Proc. Natl. Acad. Sci. USA 103, 12668–12671 (2006).
[Crossref] [PubMed]

Erickson, C. J.

S. Appelt, A. B. A. Baranga, C. J. Erickson, M. V. Romalis, A. R. Young, and W. Happer, “Theory of spin-exchange optical pumping of 3He and 129Xe,” Phys. Rev. A 58, 1412–1439 (1998).
[Crossref]

Erné, S. N.

Garachtchenko, A.

A. Garachtchenko, A. Matlashov, R. H. Kraus, and R. Cantor, “Baseline distance optimization for SQUID gradiometers,” IEEE Trans. Appl. Supercond. 9, 3676–3679 (1999).
[Crossref]

Groeger, S.

S. Groeger, G. Bison, J. L. Schenker, R. Wynands, and A. Weis, “A high-sensitivity laser-pumped Mx magnetometer,” Eur. Phys. J. D 38, 239–247 (2006).
[Crossref]

Hämäläinen, M.

M. Hämäläinen, R. Hari, R. Ilmoniemi, J. Knuutila, and O. V. Lounasmaa, “Magnetoencephalography: theory, instrumentation, and applications to noninvasive studies of the working human brain,” Rev. Mod. Phys. 65, 413–497 (1993).
[Crossref]

Happer, W.

S. Appelt, A. B. A. Baranga, C. J. Erickson, M. V. Romalis, A. R. Young, and W. Happer, “Theory of spin-exchange optical pumping of 3He and 129Xe,” Phys. Rev. A 58, 1412–1439 (1998).
[Crossref]

W. Happer and H. Tang, “Spin-exchange shift and narrowing of magnetic resonance lines in optically pumped alkali vapors,” Phys. Rev. Lett. 31, 273–276 (1973).
[Crossref]

Hari, R.

M. Hämäläinen, R. Hari, R. Ilmoniemi, J. Knuutila, and O. V. Lounasmaa, “Magnetoencephalography: theory, instrumentation, and applications to noninvasive studies of the working human brain,” Rev. Mod. Phys. 65, 413–497 (1993).
[Crossref]

Hoffman, D.

H. Xia, A. B. A. Baranga, D. Hoffman, and M. V. Romalis, “Magnetoencephalography with an atomic magnetometer,” Appl. Phys. Lett. 89, 211104 (2006).
[Crossref]

Ichihara, S.

N. Mizutani, K. Okano, K. Ban, S. Ichihara, A. Terao, and T. Kobayashi, “A plateau in the sensitivity of a compact optically pumped atomic magnetometer,” AIP Adv. 4, 057132 (2014).
[Crossref]

Ilmoniemi, R.

M. Hämäläinen, R. Hari, R. Ilmoniemi, J. Knuutila, and O. V. Lounasmaa, “Magnetoencephalography: theory, instrumentation, and applications to noninvasive studies of the working human brain,” Rev. Mod. Phys. 65, 413–497 (1993).
[Crossref]

Ito, Y.

K. Kamada, D. Sato, Y. Ito, H. Natsukawa, K. Okano, N. Mizutani, and T. Kobayashi, “Human magnetoencephalogram measurements using a newly developed compact module of high-sensitivity atomic magnetometer,” Jpn. J. Appl. Phys. 54, 026601 (2015).
[Crossref]

K. Kamada, Y. Ito, and T. Kobayashi, “Human MCG measurements with a high-sensitivity potassium atomic magnetometer,” Physiol. Meas. 33, 1063–1071 (2012).
[Crossref] [PubMed]

Y. Ito, H. Ohnishi, K. Kamada, and T. Kobayashi, “Effect of spatial homogeneity of spin polarization on magnetic field response of an optically pumped atomic magnetometer using a hybrid cell of K and Rb atoms,” IEEE Trans. Magn. 48, 3715–3718 (2012).
[Crossref]

Y. Ito, H. Ohnishi, K. Kamada, and T. Kobayashi, “Sensitivity improvement of spin-exchange relaxation free atomic magnetometers by hybrid optical pumping of potassium and rubidium,” IEEE Trans. Magn. 47, 3550–3553 (2011).
[Crossref]

Johnson, C. N.

C. N. Johnson, P. D. D. Schwindt, and M. Weisend, “Multi-sensor magnetoencephalography with atomic magnetometers,” Phys. Med. Biol. 58, 6065–6077 (2013).
[Crossref] [PubMed]

Kamada, K.

K. Kamada, D. Sato, Y. Ito, H. Natsukawa, K. Okano, N. Mizutani, and T. Kobayashi, “Human magnetoencephalogram measurements using a newly developed compact module of high-sensitivity atomic magnetometer,” Jpn. J. Appl. Phys. 54, 026601 (2015).
[Crossref]

K. Kamada, Y. Ito, and T. Kobayashi, “Human MCG measurements with a high-sensitivity potassium atomic magnetometer,” Physiol. Meas. 33, 1063–1071 (2012).
[Crossref] [PubMed]

Y. Ito, H. Ohnishi, K. Kamada, and T. Kobayashi, “Effect of spatial homogeneity of spin polarization on magnetic field response of an optically pumped atomic magnetometer using a hybrid cell of K and Rb atoms,” IEEE Trans. Magn. 48, 3715–3718 (2012).
[Crossref]

Y. Ito, H. Ohnishi, K. Kamada, and T. Kobayashi, “Sensitivity improvement of spin-exchange relaxation free atomic magnetometers by hybrid optical pumping of potassium and rubidium,” IEEE Trans. Magn. 47, 3550–3553 (2011).
[Crossref]

K. Kamada, S. Taue, and T. Kobayashi, “Optimization of bandwidth and signal responses of optically pumped atomic magnetometers for biomagnetic applications,” Jpn. J. Appl. Phys. 50, 056602 (2011).
[Crossref]

Kauer, M.

Kim, K.

Kitching, J.

S. Knappe, T. H. Sander, O. Kosch, F. Wiekhorst, J. Kitching, and L. Trahms, “Cross-validation of microfabricated atomic magnetometers with superconducting quantum interference devices for biomagnetic applications,” Appl. Phys. Lett. 97, 133703 (2010).
[Crossref]

Knappe, S.

S. Knappe, T. H. Sander, O. Kosch, F. Wiekhorst, J. Kitching, and L. Trahms, “Cross-validation of microfabricated atomic magnetometers with superconducting quantum interference devices for biomagnetic applications,” Appl. Phys. Lett. 97, 133703 (2010).
[Crossref]

Knuutila, J.

M. Hämäläinen, R. Hari, R. Ilmoniemi, J. Knuutila, and O. V. Lounasmaa, “Magnetoencephalography: theory, instrumentation, and applications to noninvasive studies of the working human brain,” Rev. Mod. Phys. 65, 413–497 (1993).
[Crossref]

Kobayashi, T.

K. Kamada, D. Sato, Y. Ito, H. Natsukawa, K. Okano, N. Mizutani, and T. Kobayashi, “Human magnetoencephalogram measurements using a newly developed compact module of high-sensitivity atomic magnetometer,” Jpn. J. Appl. Phys. 54, 026601 (2015).
[Crossref]

N. Mizutani, K. Okano, K. Ban, S. Ichihara, A. Terao, and T. Kobayashi, “A plateau in the sensitivity of a compact optically pumped atomic magnetometer,” AIP Adv. 4, 057132 (2014).
[Crossref]

Y. Ito, H. Ohnishi, K. Kamada, and T. Kobayashi, “Effect of spatial homogeneity of spin polarization on magnetic field response of an optically pumped atomic magnetometer using a hybrid cell of K and Rb atoms,” IEEE Trans. Magn. 48, 3715–3718 (2012).
[Crossref]

K. Kamada, Y. Ito, and T. Kobayashi, “Human MCG measurements with a high-sensitivity potassium atomic magnetometer,” Physiol. Meas. 33, 1063–1071 (2012).
[Crossref] [PubMed]

Y. Ito, H. Ohnishi, K. Kamada, and T. Kobayashi, “Sensitivity improvement of spin-exchange relaxation free atomic magnetometers by hybrid optical pumping of potassium and rubidium,” IEEE Trans. Magn. 47, 3550–3553 (2011).
[Crossref]

K. Kamada, S. Taue, and T. Kobayashi, “Optimization of bandwidth and signal responses of optically pumped atomic magnetometers for biomagnetic applications,” Jpn. J. Appl. Phys. 50, 056602 (2011).
[Crossref]

Koch, H.

H. Koch, “SQUID magnetocardiography: status and perspectives,” IEEE Trans. Appl. Supercond. 11, 49–59 (2001).
[Crossref]

Kominis, I. K.

I. K. Kominis, T. W. Kornack, J. C. Allred, and M. V. Romalis, “A subfemtotesla multichannel atomic magnetometer,” Nature 422, 596–599 (2003).
[Crossref] [PubMed]

Kornack, T. W.

I. K. Kominis, T. W. Kornack, J. C. Allred, and M. V. Romalis, “A subfemtotesla multichannel atomic magnetometer,” Nature 422, 596–599 (2003).
[Crossref] [PubMed]

J. C. Allred, R. N. Lyman, T. W. Kornack, and M. V. Romalis, “High-sensitivity atomic magnetometer unaffected by spin-exchange relaxation,” Phys. Rev. Lett. 89, 130801 (2002).
[Crossref] [PubMed]

Kosch, O.

S. Knappe, T. H. Sander, O. Kosch, F. Wiekhorst, J. Kitching, and L. Trahms, “Cross-validation of microfabricated atomic magnetometers with superconducting quantum interference devices for biomagnetic applications,” Appl. Phys. Lett. 97, 133703 (2010).
[Crossref]

Kraus, R. H.

A. Garachtchenko, A. Matlashov, R. H. Kraus, and R. Cantor, “Baseline distance optimization for SQUID gradiometers,” IEEE Trans. Appl. Supercond. 9, 3676–3679 (1999).
[Crossref]

Ledbetter, M. P.

M. P. Ledbetter, I. M. Savukov, V. M. Acosta, D. Budker, and M. V. Romalis, “Spin-exchange-relaxation-free magnetometry with Cs vapor,” Phys. Rev. A 77, 033408 (2008).
[Crossref]

Lee, H. J.

Lembke, G.

Lounasmaa, O. V.

M. Hämäläinen, R. Hari, R. Ilmoniemi, J. Knuutila, and O. V. Lounasmaa, “Magnetoencephalography: theory, instrumentation, and applications to noninvasive studies of the working human brain,” Rev. Mod. Phys. 65, 413–497 (1993).
[Crossref]

Lyman, R. N.

J. C. Allred, R. N. Lyman, T. W. Kornack, and M. V. Romalis, “High-sensitivity atomic magnetometer unaffected by spin-exchange relaxation,” Phys. Rev. Lett. 89, 130801 (2002).
[Crossref] [PubMed]

Matlashov, A.

A. Garachtchenko, A. Matlashov, R. H. Kraus, and R. Cantor, “Baseline distance optimization for SQUID gradiometers,” IEEE Trans. Appl. Supercond. 9, 3676–3679 (1999).
[Crossref]

Menhorn, B.

Mizutani, N.

K. Kamada, D. Sato, Y. Ito, H. Natsukawa, K. Okano, N. Mizutani, and T. Kobayashi, “Human magnetoencephalogram measurements using a newly developed compact module of high-sensitivity atomic magnetometer,” Jpn. J. Appl. Phys. 54, 026601 (2015).
[Crossref]

N. Mizutani, K. Okano, K. Ban, S. Ichihara, A. Terao, and T. Kobayashi, “A plateau in the sensitivity of a compact optically pumped atomic magnetometer,” AIP Adv. 4, 057132 (2014).
[Crossref]

Moon, H. S.

Natsukawa, H.

K. Kamada, D. Sato, Y. Ito, H. Natsukawa, K. Okano, N. Mizutani, and T. Kobayashi, “Human magnetoencephalogram measurements using a newly developed compact module of high-sensitivity atomic magnetometer,” Jpn. J. Appl. Phys. 54, 026601 (2015).
[Crossref]

Nowak, H.

Ohnishi, H.

Y. Ito, H. Ohnishi, K. Kamada, and T. Kobayashi, “Effect of spatial homogeneity of spin polarization on magnetic field response of an optically pumped atomic magnetometer using a hybrid cell of K and Rb atoms,” IEEE Trans. Magn. 48, 3715–3718 (2012).
[Crossref]

Y. Ito, H. Ohnishi, K. Kamada, and T. Kobayashi, “Sensitivity improvement of spin-exchange relaxation free atomic magnetometers by hybrid optical pumping of potassium and rubidium,” IEEE Trans. Magn. 47, 3550–3553 (2011).
[Crossref]

Okano, K.

K. Kamada, D. Sato, Y. Ito, H. Natsukawa, K. Okano, N. Mizutani, and T. Kobayashi, “Human magnetoencephalogram measurements using a newly developed compact module of high-sensitivity atomic magnetometer,” Jpn. J. Appl. Phys. 54, 026601 (2015).
[Crossref]

N. Mizutani, K. Okano, K. Ban, S. Ichihara, A. Terao, and T. Kobayashi, “A plateau in the sensitivity of a compact optically pumped atomic magnetometer,” AIP Adv. 4, 057132 (2014).
[Crossref]

Pasquarelli, A.

Pines, A.

S. Xu, V. V. Yashchuk, M. H. Donaldson, S. M. Rochester, D. Budker, and A. Pines, “Magnetic resonance imaging with an optical atomic magnetometer,” Proc. Natl. Acad. Sci. USA 103, 12668–12671 (2006).
[Crossref] [PubMed]

Rochester, S. M.

S. Xu, V. V. Yashchuk, M. H. Donaldson, S. M. Rochester, D. Budker, and A. Pines, “Magnetic resonance imaging with an optical atomic magnetometer,” Proc. Natl. Acad. Sci. USA 103, 12668–12671 (2006).
[Crossref] [PubMed]

Romalis, M. V.

M. P. Ledbetter, I. M. Savukov, V. M. Acosta, D. Budker, and M. V. Romalis, “Spin-exchange-relaxation-free magnetometry with Cs vapor,” Phys. Rev. A 77, 033408 (2008).
[Crossref]

D. Budker and M. V. Romalis, “Optical magnetometry,” Nat. Phys. 3, 227–234 (2007).
[Crossref]

H. Xia, A. B. A. Baranga, D. Hoffman, and M. V. Romalis, “Magnetoencephalography with an atomic magnetometer,” Appl. Phys. Lett. 89, 211104 (2006).
[Crossref]

I. M. Savukov, S. J. Seltzer, M. V. Romalis, and K. L. Sauer, “Tunable atomic magnetometer for detection of radio-frequency magnetic fields,” Phys. Rev. Lett. 95, 063004 (2005).
[Crossref] [PubMed]

I. M. Savukov and M. V. Romalis, “Effects of spin-exchange collisions in a high-density alkali-metal vapor in low magnetic fields,” Phys. Rev. A 71, 023405 (2005).
[Crossref]

I. K. Kominis, T. W. Kornack, J. C. Allred, and M. V. Romalis, “A subfemtotesla multichannel atomic magnetometer,” Nature 422, 596–599 (2003).
[Crossref] [PubMed]

J. C. Allred, R. N. Lyman, T. W. Kornack, and M. V. Romalis, “High-sensitivity atomic magnetometer unaffected by spin-exchange relaxation,” Phys. Rev. Lett. 89, 130801 (2002).
[Crossref] [PubMed]

S. Appelt, A. B. A. Baranga, C. J. Erickson, M. V. Romalis, A. R. Young, and W. Happer, “Theory of spin-exchange optical pumping of 3He and 129Xe,” Phys. Rev. A 58, 1412–1439 (1998).
[Crossref]

Sander, T. H.

S. Knappe, T. H. Sander, O. Kosch, F. Wiekhorst, J. Kitching, and L. Trahms, “Cross-validation of microfabricated atomic magnetometers with superconducting quantum interference devices for biomagnetic applications,” Appl. Phys. Lett. 97, 133703 (2010).
[Crossref]

Sato, D.

K. Kamada, D. Sato, Y. Ito, H. Natsukawa, K. Okano, N. Mizutani, and T. Kobayashi, “Human magnetoencephalogram measurements using a newly developed compact module of high-sensitivity atomic magnetometer,” Jpn. J. Appl. Phys. 54, 026601 (2015).
[Crossref]

Sauer, K. L.

I. M. Savukov, S. J. Seltzer, M. V. Romalis, and K. L. Sauer, “Tunable atomic magnetometer for detection of radio-frequency magnetic fields,” Phys. Rev. Lett. 95, 063004 (2005).
[Crossref] [PubMed]

Savukov, I. M.

M. P. Ledbetter, I. M. Savukov, V. M. Acosta, D. Budker, and M. V. Romalis, “Spin-exchange-relaxation-free magnetometry with Cs vapor,” Phys. Rev. A 77, 033408 (2008).
[Crossref]

I. M. Savukov, S. J. Seltzer, M. V. Romalis, and K. L. Sauer, “Tunable atomic magnetometer for detection of radio-frequency magnetic fields,” Phys. Rev. Lett. 95, 063004 (2005).
[Crossref] [PubMed]

I. M. Savukov and M. V. Romalis, “Effects of spin-exchange collisions in a high-density alkali-metal vapor in low magnetic fields,” Phys. Rev. A 71, 023405 (2005).
[Crossref]

Schenker, J. L.

S. Groeger, G. Bison, J. L. Schenker, R. Wynands, and A. Weis, “A high-sensitivity laser-pumped Mx magnetometer,” Eur. Phys. J. D 38, 239–247 (2006).
[Crossref]

Schwindt, P. D. D.

C. N. Johnson, P. D. D. Schwindt, and M. Weisend, “Multi-sensor magnetoencephalography with atomic magnetometers,” Phys. Med. Biol. 58, 6065–6077 (2013).
[Crossref] [PubMed]

Seltzer, S. J.

I. M. Savukov, S. J. Seltzer, M. V. Romalis, and K. L. Sauer, “Tunable atomic magnetometer for detection of radio-frequency magnetic fields,” Phys. Rev. Lett. 95, 063004 (2005).
[Crossref] [PubMed]

Shah, V. K.

V. K. Shah and R. T. Wakai, “A compact, high performance atomic magnetometer for biomedical applications,” Phys. Med. Biol. 58, 8153–8161 (2013).
[Crossref] [PubMed]

Shim, J. H.

Suter, D.

D. Suter, The physics of laser-atom interactions (Cambridge University, 1997).
[Crossref]

Tang, H.

W. Happer and H. Tang, “Spin-exchange shift and narrowing of magnetic resonance lines in optically pumped alkali vapors,” Phys. Rev. Lett. 31, 273–276 (1973).
[Crossref]

Taue, S.

K. Kamada, S. Taue, and T. Kobayashi, “Optimization of bandwidth and signal responses of optically pumped atomic magnetometers for biomagnetic applications,” Jpn. J. Appl. Phys. 50, 056602 (2011).
[Crossref]

Terao, A.

N. Mizutani, K. Okano, K. Ban, S. Ichihara, A. Terao, and T. Kobayashi, “A plateau in the sensitivity of a compact optically pumped atomic magnetometer,” AIP Adv. 4, 057132 (2014).
[Crossref]

Trahms, L.

S. Knappe, T. H. Sander, O. Kosch, F. Wiekhorst, J. Kitching, and L. Trahms, “Cross-validation of microfabricated atomic magnetometers with superconducting quantum interference devices for biomagnetic applications,” Appl. Phys. Lett. 97, 133703 (2010).
[Crossref]

Wakai, R. T.

V. K. Shah and R. T. Wakai, “A compact, high performance atomic magnetometer for biomedical applications,” Phys. Med. Biol. 58, 8153–8161 (2013).
[Crossref] [PubMed]

R. Wyllie, M. Kauer, R. T. Wakai, and T. G. Walker, “Optical magnetometer array for fetal magnetocardiography,” Opt. Lett. 37, 2247–2249 (2012).
[Crossref] [PubMed]

Walker, T. G.

Weis, A.

S. Groeger, G. Bison, J. L. Schenker, R. Wynands, and A. Weis, “A high-sensitivity laser-pumped Mx magnetometer,” Eur. Phys. J. D 38, 239–247 (2006).
[Crossref]

G. Bison, R. Wynands, and A. Weis, “Dynamical mapping of the human cardiomagnetic field with a room-temperature, laser-optical sensor,” Opt. Express 11, 904–909 (2003).
[Crossref] [PubMed]

Weisend, M.

C. N. Johnson, P. D. D. Schwindt, and M. Weisend, “Multi-sensor magnetoencephalography with atomic magnetometers,” Phys. Med. Biol. 58, 6065–6077 (2013).
[Crossref] [PubMed]

Wiekhorst, F.

S. Knappe, T. H. Sander, O. Kosch, F. Wiekhorst, J. Kitching, and L. Trahms, “Cross-validation of microfabricated atomic magnetometers with superconducting quantum interference devices for biomagnetic applications,” Appl. Phys. Lett. 97, 133703 (2010).
[Crossref]

Wyllie, R.

Wynands, R.

S. Groeger, G. Bison, J. L. Schenker, R. Wynands, and A. Weis, “A high-sensitivity laser-pumped Mx magnetometer,” Eur. Phys. J. D 38, 239–247 (2006).
[Crossref]

G. Bison, R. Wynands, and A. Weis, “Dynamical mapping of the human cardiomagnetic field with a room-temperature, laser-optical sensor,” Opt. Express 11, 904–909 (2003).
[Crossref] [PubMed]

Xia, H.

H. Xia, A. B. A. Baranga, D. Hoffman, and M. V. Romalis, “Magnetoencephalography with an atomic magnetometer,” Appl. Phys. Lett. 89, 211104 (2006).
[Crossref]

Xu, S.

S. Xu, V. V. Yashchuk, M. H. Donaldson, S. M. Rochester, D. Budker, and A. Pines, “Magnetic resonance imaging with an optical atomic magnetometer,” Proc. Natl. Acad. Sci. USA 103, 12668–12671 (2006).
[Crossref] [PubMed]

Yashchuk, V. V.

S. Xu, V. V. Yashchuk, M. H. Donaldson, S. M. Rochester, D. Budker, and A. Pines, “Magnetic resonance imaging with an optical atomic magnetometer,” Proc. Natl. Acad. Sci. USA 103, 12668–12671 (2006).
[Crossref] [PubMed]

Young, A. R.

S. Appelt, A. B. A. Baranga, C. J. Erickson, M. V. Romalis, A. R. Young, and W. Happer, “Theory of spin-exchange optical pumping of 3He and 129Xe,” Phys. Rev. A 58, 1412–1439 (1998).
[Crossref]

AIP Adv. (1)

N. Mizutani, K. Okano, K. Ban, S. Ichihara, A. Terao, and T. Kobayashi, “A plateau in the sensitivity of a compact optically pumped atomic magnetometer,” AIP Adv. 4, 057132 (2014).
[Crossref]

Appl. Phys. Lett. (2)

S. Knappe, T. H. Sander, O. Kosch, F. Wiekhorst, J. Kitching, and L. Trahms, “Cross-validation of microfabricated atomic magnetometers with superconducting quantum interference devices for biomagnetic applications,” Appl. Phys. Lett. 97, 133703 (2010).
[Crossref]

H. Xia, A. B. A. Baranga, D. Hoffman, and M. V. Romalis, “Magnetoencephalography with an atomic magnetometer,” Appl. Phys. Lett. 89, 211104 (2006).
[Crossref]

Biomed. Opt. Express (1)

Eur. Phys. J. D (1)

S. Groeger, G. Bison, J. L. Schenker, R. Wynands, and A. Weis, “A high-sensitivity laser-pumped Mx magnetometer,” Eur. Phys. J. D 38, 239–247 (2006).
[Crossref]

IEEE Trans. Appl. Supercond. (2)

A. Garachtchenko, A. Matlashov, R. H. Kraus, and R. Cantor, “Baseline distance optimization for SQUID gradiometers,” IEEE Trans. Appl. Supercond. 9, 3676–3679 (1999).
[Crossref]

H. Koch, “SQUID magnetocardiography: status and perspectives,” IEEE Trans. Appl. Supercond. 11, 49–59 (2001).
[Crossref]

IEEE Trans. Magn. (2)

Y. Ito, H. Ohnishi, K. Kamada, and T. Kobayashi, “Sensitivity improvement of spin-exchange relaxation free atomic magnetometers by hybrid optical pumping of potassium and rubidium,” IEEE Trans. Magn. 47, 3550–3553 (2011).
[Crossref]

Y. Ito, H. Ohnishi, K. Kamada, and T. Kobayashi, “Effect of spatial homogeneity of spin polarization on magnetic field response of an optically pumped atomic magnetometer using a hybrid cell of K and Rb atoms,” IEEE Trans. Magn. 48, 3715–3718 (2012).
[Crossref]

Jpn. J. Appl. Phys. (2)

K. Kamada, D. Sato, Y. Ito, H. Natsukawa, K. Okano, N. Mizutani, and T. Kobayashi, “Human magnetoencephalogram measurements using a newly developed compact module of high-sensitivity atomic magnetometer,” Jpn. J. Appl. Phys. 54, 026601 (2015).
[Crossref]

K. Kamada, S. Taue, and T. Kobayashi, “Optimization of bandwidth and signal responses of optically pumped atomic magnetometers for biomagnetic applications,” Jpn. J. Appl. Phys. 50, 056602 (2011).
[Crossref]

Nat. Phys. (1)

D. Budker and M. V. Romalis, “Optical magnetometry,” Nat. Phys. 3, 227–234 (2007).
[Crossref]

Nature (1)

I. K. Kominis, T. W. Kornack, J. C. Allred, and M. V. Romalis, “A subfemtotesla multichannel atomic magnetometer,” Nature 422, 596–599 (2003).
[Crossref] [PubMed]

Opt. Express (2)

Opt. Lett. (1)

Phys. Med. Biol. (2)

C. N. Johnson, P. D. D. Schwindt, and M. Weisend, “Multi-sensor magnetoencephalography with atomic magnetometers,” Phys. Med. Biol. 58, 6065–6077 (2013).
[Crossref] [PubMed]

V. K. Shah and R. T. Wakai, “A compact, high performance atomic magnetometer for biomedical applications,” Phys. Med. Biol. 58, 8153–8161 (2013).
[Crossref] [PubMed]

Phys. Rev. A (3)

M. P. Ledbetter, I. M. Savukov, V. M. Acosta, D. Budker, and M. V. Romalis, “Spin-exchange-relaxation-free magnetometry with Cs vapor,” Phys. Rev. A 77, 033408 (2008).
[Crossref]

S. Appelt, A. B. A. Baranga, C. J. Erickson, M. V. Romalis, A. R. Young, and W. Happer, “Theory of spin-exchange optical pumping of 3He and 129Xe,” Phys. Rev. A 58, 1412–1439 (1998).
[Crossref]

I. M. Savukov and M. V. Romalis, “Effects of spin-exchange collisions in a high-density alkali-metal vapor in low magnetic fields,” Phys. Rev. A 71, 023405 (2005).
[Crossref]

Phys. Rev. Lett. (3)

I. M. Savukov, S. J. Seltzer, M. V. Romalis, and K. L. Sauer, “Tunable atomic magnetometer for detection of radio-frequency magnetic fields,” Phys. Rev. Lett. 95, 063004 (2005).
[Crossref] [PubMed]

W. Happer and H. Tang, “Spin-exchange shift and narrowing of magnetic resonance lines in optically pumped alkali vapors,” Phys. Rev. Lett. 31, 273–276 (1973).
[Crossref]

J. C. Allred, R. N. Lyman, T. W. Kornack, and M. V. Romalis, “High-sensitivity atomic magnetometer unaffected by spin-exchange relaxation,” Phys. Rev. Lett. 89, 130801 (2002).
[Crossref] [PubMed]

Physiol. Meas. (1)

K. Kamada, Y. Ito, and T. Kobayashi, “Human MCG measurements with a high-sensitivity potassium atomic magnetometer,” Physiol. Meas. 33, 1063–1071 (2012).
[Crossref] [PubMed]

Proc. Natl. Acad. Sci. USA (1)

S. Xu, V. V. Yashchuk, M. H. Donaldson, S. M. Rochester, D. Budker, and A. Pines, “Magnetic resonance imaging with an optical atomic magnetometer,” Proc. Natl. Acad. Sci. USA 103, 12668–12671 (2006).
[Crossref] [PubMed]

Rev. Mod. Phys. (1)

M. Hämäläinen, R. Hari, R. Ilmoniemi, J. Knuutila, and O. V. Lounasmaa, “Magnetoencephalography: theory, instrumentation, and applications to noninvasive studies of the working human brain,” Rev. Mod. Phys. 65, 413–497 (1993).
[Crossref]

Other (1)

D. Suter, The physics of laser-atom interactions (Cambridge University, 1997).
[Crossref]

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Figures (6)

Fig. 1
Fig. 1

(a) Principle of an optical gradiometer. Two pump beams are made of right-handed circularly polarized light. The probe beam is linearly polarized. The polarimeter consists of a polarizing beam splitter and two photodetectors. (b) Transition of the polarization plane of the probe beam when the magnetic fields at the two positions are same. (c) Transition of the polarization plane of the probe beam when the magnetic fields at the two positions are different. The polarization planes at points A – D in (a) are drawn from the traveling direction of the probe beam. θLower and θUpper are the angles of the magneto-optical rotations generated at the lower and upper positions, respectively. θDiff is the difference between θLower and θUpper.

Fig. 2
Fig. 2

Arrangement of the optical gradiometer. (a) Top view of the measurement system. CLs are cylindrical lenses. The K cell is surrounded by AlN and heaters for uniform heating, and covered by thermal insulators (TI). Four vacuum glass cells are used as windows for the beam paths. (b) Another view of the optical components for the pump beams. PBS is a polarizing beam splitter. One pump beam is expanded and separated. Two beams are circularly polarized by quarter wavelength plates and irradiate the K cell in (a) at different heights, respectively. (c) Another view of the optical components for the probe beam. The probe beam at the lower position is linearly polarized by a half wavelength plate and irradiates the cell. The probe beam is reflected in (d) and comes back from with different height. The polarization plane of the probe beam at the upper position is measured by the polarimeter (PM), which consists of a polarizing beam splitter and two photodetectors. The differential output of the photodetectors is amplified and recorded in the PC in (a). The half wavelength plate before the polarimeter rotates the polarization plane to 45° so that the output becomes zero when there is no magnetic field. (d) Another view of the mirrors for the probe beam. The probe beam is reflected to the right angle twice and raised 30 mm.

Fig. 3
Fig. 3

Signal responses as functions of the wavelength of the probe beam. The blue circles and the red squares denote measured results at the upper and lower positions, respectively. The blue solid line and red broken line denote calculated results obtained by Eqs. (1)(6).

Fig. 4
Fig. 4

Ratio of signal responses of the upper and lower positions as functions of the wavelength of the probe beam.

Fig. 5
Fig. 5

Calibrated noise spectrum density of the optical gradiometer. The blue solid line denotes the magnetic noise floor of the single measurement at the upper position. The black solid line denotes the magnetic noise floor of the differential measurement. The gray broken line denotes the probe-beam noise floor.

Fig. 6
Fig. 6

Calibrated noise spectrum density of the pseudo-magnetic noise and signal. The blue solid line and the red broken line denote the upper and lower output, respectively, and these lines are overlapped over the entire measured frequency range. The black solid line denotes the differential output.

Tables (1)

Tables Icon

Table 1 SNR of the optical gradiometer. The signal is the amplitude of 10 Hz wave. The noise is the mean value of the noise spectrum density from 8 to 12 Hz, except at 10 Hz. The unit of signal and noise is fTrms/Hz1/2.

Equations (7)

Equations on this page are rendered with MathJax. Learn more.

S out = η I probe e α l sin ( 2 θ ) ,
α = n K c r e f Γ / 2 ( ν probe ν 0 ) 2 + ( Γ / 2 ) 2 ,
θ = n K c r e f ν probe ν 0 ( ν probe ν 0 ) 2 + ( Γ / 2 ) 2 l cross S x ,
d d t S = D 2 S + γ e q S × B 1 T 2 S + 1 2 q ( 0 0 R OP ) ,
1 T 2 = 1 q ( R OP + R SD + R PR + 1 T 2 SE ) ,
R PR = I probe h ν probe A probe n K l ( 1 e α l ) .
θ Diff = θ Lower θ Upper .

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