Magnetic field imaging with microfabricated optically-pumped magnetometers
Orang Alem, Rahul Mhaskar, Ricardo Jimenez-Martinez, Dong Sheng, John LeBlanc, Lutz Trahms, Tilman Sander, Svenja A. Knappe
A multichannel imaging system is presented, consisting of 25 microfabricated optically-pumped magnetometers. The sensor probes have a footprint of less than 1 cm2 and a sensitive volume of (1.5 mm)3. They are connected to a control unit through optical fibers of length 5 m. At very low ambient magnetic fields, the magnetic sensors array has an average sensitivity of 24 fT/Hz1/2, with a standard deviation of 5 fT/Hz1/2 when the noise of each sensor is averaged between 10 and 50 Hz. In Earth's magnetic field, the magnetometers have a field sensitivity around 5 pT/Hz1/2. The vacuum-packaged sensor heads are optically heated and consume 76 ± 7 mW of power each. The heating power is provided by an array of 8 diode lasers. As an example, magnetic field images of small probe coils were obtained with the sensor array. Fits to the expected field pattern agree well with the measured data.
, Mhaskar, R.
, Jimenez-Martinez, R.
, Sheng, D.
, LeBlanc, J.
, Trahms, L.
, Sander, T.
and Knappe, S.
Magnetic field imaging with microfabricated optically-pumped magnetometers, Optics Express
(Accessed June 6, 2023)