Electromagnetic induction imaging with atomic magnetometers has disclosed unprecedented domains for imaging, from security screening to material characterization. However, applications to low-conductivity specimens—most notably for biomedical imaging—require sensitivity, stability, and tunability only speculated thus far. Here, we demonstrate contactless and noninvasive imaging down to 50 S m−1 using a 50 fT/Hz87Rb radio frequency atomic magnetometer operating in an unshielded environment and near room temperature. Two-dimensional images of test objects are obtained with a near-resonant imaging approach, which reduces the phase noise by a factor 172, with a projected sensitivity of 1 S m−1. Our results, an improvement of more than three orders of magnitude on previous imaging demonstrations, push electromagnetic imaging with atomic magnetometers to regions of interest for semiconductors, insulators, and biological tissues.

1.
W. T.
Joines
,
Y.
Zhang
,
C.
Li
, and
R. L.
Jirtle
, “
The measured electrical properties of normal and malignant human tissues from 50 to 900 MHz
,”
Med. Phys.
21
,
547
550
(
1994
).
2.
L.
Marmugi
and
F.
Renzoni
, “
Optical magnetic induction tomography of the heart
,”
Sci. Rep.
6
,
23962
(
2016
).
3.
H.
Griffiths
, “
Magnetic induction tomography
,”
Meas. Sci. Technol.
12
,
1126
(
2001
).
4.
H.
Griffiths
,
W. R.
Stewart
, and
W.
Gough
, “
Magnetic induction tomography: A measuring system for biological tissues
,”
Ann. New York Acad. Sci.
873
,
335
345
(
1999
).
5.
R.
Merwa
,
K.
Hollaus
,
O.
Biró
, and
H.
Scharfetter
, “
Detection of brain oedema using magnetic induction tomography: A feasibility study of the likely sensitivity and detectability
,”
Physiol. Meas.
25
,
347
354
(
2004
).
6.
M.
Zolgharni
,
H.
Griffiths
, and
P. D.
Ledger
, “
Frequency-difference MIT imaging of cerebral haemorrhage with a hemispherical coil array: numerical modelling
,”
Physiol. Meas.
31
,
S111
S125
(
2010
).
7.
W.
Pan
,
Q.
Yan
,
M.
Qin
,
G.
Jin
,
J.
Sun
,
X.
Ning
,
W.
Zhuang
,
B.
Peng
, and
G.
Li
, “
Detection of cerebral hemorrhage in rabbits by time-difference magnetic inductive phase shift spectroscopy
,”
PLoS One
10
,
1
14
(
2015
).
8.
H.
Griffiths
,
W.
Gough
,
S.
Watson
, and
R. J.
Williams
, “
Residual capacitive coupling and the measurement of permittivity in magnetic induction tomography
,”
Physiol. Meas.
28
,
S301
(
2007
).
9.
C.
Deans
,
L.
Marmugi
,
S.
Hussain
, and
F.
Renzoni
, “
Electromagnetic induction imaging with a radio-frequency atomic magnetometer
,”
Appl. Phys. Lett.
108
,
103503
(
2016
).
10.
A.
Wickenbrock
,
N.
Leefer
,
J. W.
Blanchard
, and
D.
Budker
, “
Eddy current imaging with an atomic radio-frequency magnetometer
,”
Appl. Phys. Lett.
108
,
183507
(
2016
).
11.
C.
Deans
,
L. D.
Griffin
,
L.
Marmugi
, and
F.
Renzoni
, “
Machine learning based localization and classification with atomic magnetometers
,”
Phys. Rev. Lett.
120
,
033204
(
2018
).
12.
P.
Bevington
,
R.
Gartman
,
W.
Chalupczak
,
C.
Deans
,
L.
Marmugi
, and
F.
Renzoni
, “
Non-destructive structural imaging of steelwork with atomic magnetometers
,”
Appl. Phys. Lett.
113
,
063503
(
2018
).
13.
P.
Bevington
,
R.
Gartman
, and
W.
Chalupczak
, “
Imaging of material defects with a radio-frequency atomic magnetometer
,”
Rev. Sci. Instrum.
90
,
013103
(
2019
).
14.
P.
Bevington
,
R.
Gartman
, and
W.
Chalupczak
, “
Enhanced material defect imaging with a radio-frequency atomic magnetometer
,”
J. Appl. Phys.
125
,
094503
(
2019
).
15.
C.
Deans
,
L.
Marmugi
, and
F.
Renzoni
, “
Through-barrier electromagnetic imaging with an atomic magnetometer
,”
Opt. Express
25
,
17911
17917
(
2017
).
16.
C.
Deans
,
L.
Marmugi
, and
F.
Renzoni
, “
Active underwater detection with an array of atomic magnetometers
,”
Appl. Opt.
57
,
2346
2351
(
2018
).
17.
G.
Chatzidrosos
,
A.
Wickenbrock
,
L.
Bougas
,
H.
Zheng
,
O.
Tretiak
,
Y.
Yang
, and
D.
Budker
, “
Eddy-current imaging with nitrogen-vacancy centers in diamond
,”
Phys. Rev. Appl.
11
,
014060
(
2019
).
18.
D.
Budker
and
M.
Romalis
, “
Optical magnetometry
,”
Nat. Phys.
3
,
227
(
2007
).
19.
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
).
20.
M. P.
Ledbetter
,
V. M.
Acosta
,
S. M.
Rochester
,
D.
Budker
,
S.
Pustelny
, and
V. V.
Yashchuk
, “
Detection of radio-frequency magnetic fields using nonlinear magneto-optical rotation
,”
Phys. Rev. A
75
,
023405
(
2007
).
21.
W.
Chalupczak
,
R. M.
Godun
,
S.
Pustelny
, and
W.
Gawlik
, “
Room temperature femtotesla radio-frequency atomic magnetometer
,”
Appl. Phys. Lett.
100
,
242401
(
2012
).
22.
C.
Deans
,
L.
Marmugi
, and
F.
Renzoni
, “
Sub-picotesla widely tunable atomic magnetometer operating at room-temperature in unshielded environments
,”
Rev. Sci. Instrum.
89
,
083111
(
2018
).
23.
J.
Belfi
,
G.
Bevilacqua
,
V.
Biancalana
,
S.
Cartaleva
,
Y.
Dancheva
, and
L.
Moi
, “
Cesium coherent population trapping magnetometer for cardiosignal detection in an unshielded environment
,”
J. Opt. Soc. Am., B
24
,
2357
2362
(
2007
).
24.
H.
Xia
,
A.
Ben-Amar Baranga
,
D.
Hoffman
, and
M. V.
Romalis
, “
Magnetoencephalography with an atomic magnetometer
,”
Appl. Phys. Lett.
89
,
211104
(
2006
).
25.
K.
Jensen
,
M. A.
Skarsfeldt
,
H.
Stærkind
,
J.
Arnbak
,
M. V.
Balabas
,
S.-P.
Olesen
,
B. H.
Bentzen
, and
E. S.
Polzik
, “
Magnetocardiography on an isolated animal heart with a room-temperature optically pumped magnetometer
,”
Sci. Rep.
8
,
16218
(
2018
).
26.
J. F.
Barry
,
M. J.
Turner
,
J. M.
Schloss
,
D. R.
Glenn
,
Y.
Song
,
M. D.
Lukin
,
H.
Park
, and
R. L.
Walsworth
, “
Optical magnetic detection of single-neuron action potentials using quantum defects in diamond
,”
Proc. Natl. Acad. Sci.
113
,
14133
14138
(
2016
).
27.
A.
Vander Vorst
,
A.
Rosen
, and
Y.
Kotsuka
,
RF/Microwave Interaction with Biological Tissues
(
John Wiley & Sons
,
2006
), Vol.
181
.
28.
M.
Lu
,
W.
Zhu
,
L.
Yin
,
A.
Peyton
, and
W.
Yin
, “
Reducing the lift-off effect on permeability measurement for magnetic plates from multi-frequency induction data
,”
IEEE Trans. Instrum. Meas.
67
(
1
),
167
(
2017
).
29.
M.
O'Toole
,
N.
Karimian
, and
A. J.
Peyton
, “
Classification of non-ferrous metals using magnetic induction spectroscopy
,”
IEEE Trans. Ind. Inf.
PP
,
1
(
2018
).
30.
G.
Bevilacqua
,
V.
Biancalana
,
Y.
Dancheva
, and
A.
Vigilante
, “
Self-adaptive loop for external-disturbance reduction in a differential measurement setup
,”
Phys. Rev. Appl.
11
,
014029
(
2019
).
31.
C.
Deans
,
L.
Marmugi
,
S.
Hussain
, and
F.
Renzoni
, “
Optical atomic magnetometry for magnetic induction tomography of the heart
,”
Proc. SPIE
9900
,
10
(
2016
).
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