Eddy current imaging with an atomic radio-frequency magnetometer

We use a radio-frequency $^{85}$Rb alkali-vapor cell magnetometer based on a paraffin-coated cell with long spin-coherence time and a small, low-inductance driving coil to create highly resolved conductivity maps of different objects. We resolve sub-mm features in conductive objects, we characterize the frequency response of our technique, and by operating at frequencies up to 250 kHz we are able to discriminate between differently conductive materials based on the induced response. The method is suited to cover a wide range of driving frequencies and can potentially be used for detecting non-metallic objects with low DC conductivity.

[1]  D. Budker,et al.  Robust, high-speed, all-optical atomic magnetometer , 2006 .

[2]  C. Wieman,et al.  Frequency-stabilized diode laser with the Zeeman shift in an atomic vapor. , 1998, Applied optics.

[3]  Marc Kreutzbruck,et al.  Recent developments in SQUID NDE , 2002 .

[4]  H. Griffiths.  Magnetic induction tomography , 2001 .

[5]  Stuart T. Smith,et al.  Giant magnetoresistance-based eddy-current sensor , 2001 .

[6]  Javier García-Martín,et al.  Non-Destructive Techniques Based on Eddy Current Testing , 2011, Sensors.

[7]  Krzysztof T. Pozniak,et al.  Measurement Science and Technology 18 (8), art no , 2005 .

[8]  John P. Wikswo,et al.  SQUIDs for nondestructive evaluation , 1997 .

[9]  Ferruccio Renzoni,et al.  Electromagnetic imaging through thick metallic enclosures , 2015 .

[10]  Paul Bartlett,et al.  Magnetic Imaging: a New Tool for UK National Nuclear Security , 2015, Scientific Reports.

[11]  W. Gawlik,et al.  Laser frequency stabilization by Doppler-free magnetic dichroism , 2002 .

[12]  Zach DeVito,et al.  Opt , 2017 .

[13]  Steffen Leonhardt,et al.  The MAIN Shirt: A Textile-Integrated Magnetic Induction Sensor Array , 2014, Sensors.

[14]  M. Romalis,et al.  Tunable atomic magnetometer for detection of radio-frequency magnetic fields. , 2005, Physical review letters.

[15]  J. Kitching,et al.  Microfabricated alkali atom vapor cells , 2004 .

[16]  Andrew G. Glen,et al.  APPL , 2001 .

[17]  Ferruccio Renzoni,et al.  Magnetic induction measurements using an all-optical $^{87}$Rb atomic magnetometer , 2013, 1309.5341.

[18]  Wuliang Yin,et al.  Thickness measurement of non-magnetic plates using multi-frequency eddy current sensors , 2007 .

[19]  Zhiwei Zeng,et al.  Pulsed Eddy-Current Based Giant Magnetoresistive System for the Inspection of Aircraft Structures , 2010, IEEE Transactions on Magnetics.

[20]  W. Marsden.  I and J , 2012 .

[21]  J. Rudlin,et al.  Multiple sensors on pulsed eddy-current detection for 3-D subsurface crack assessment , 2005, IEEE Sensors Journal.

[22]  R. Knabb,et al.  ANNALS OF THE NEW YORK ACADEMY OF SCIENCES , 2014, Annals of the New York Academy of Sciences.

[23]  A Korjenevsky,et al.  Magnetic induction tomography: experimental realization. , 2000, Physiological measurement.

[24]  Detection of radio-frequency magnetic fields using nonlinear magneto-optical rotation , 2006, physics/0609196.

[25]  Cameron Deans,et al.  Electromagnetic induction imaging with a radio-frequency atomic magnetometer , 2016, 1603.03412.

[26]  W. Gawlik,et al.  Sensitive optical magnetometry based on nonlinear magneto-optical rotation with amplitude-modulated light , 2007, 2007 European Conference on Lasers and Electro-Optics and the International Quantum Electronics Conference.

[27]  Luca Marmugi,et al.  Magnetic induction tomography using an all-optical ⁸⁷Rb atomic magnetometer. , 2014, Optics letters.

[28]  J. R. Claycomb,et al.  PRACTICAL SQUID INSTRUMENT FOR NONDESTRUCTIVE TESTING , 1997 .

[29]  D. Budker,et al.  Optical magnetometry - eScholarship , 2006, physics/0611246.

[30]  D. Budker,et al.  Small-sized dichroic atomic vapor laser lock. , 2010, The Review of scientific instruments.

[31]  H Griffiths,et al.  Magnetic Induction Tomography: A Measuring System for Biological Tissues , 1999, Annals of the New York Academy of Sciences.