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Quantum Magnetometry

Scientific Profile 

The Quantum Magnetometry working group is dedicated to the research and development of atomic quantum sensors for the ultrasensitive detection of magnetic fields in biophotonic and geophysical applications as well as tools for fundamental physics research. Central research focus is on optically pumped magnetometers (OPM) for innovative and in particular imaging techniques for the measurement of magnetic field or quantities connected to it. The research ranges from the investigation of basic light-matter interactions, resulting tailored sensor principles, their implementation into integrated demonstrator systems, to the development of entire measurement instruments ready for in-field use or the intended application scenario. This includes the microfabrication of single functionalized alkali vapor cells as well as cell arrays, the use of innovative assembly and interconnection technologies for system integration and the development of advanced sensor readout electronics. In addition, sophisticated data processing routines, inversion and interpretation methods are developed and used, another field where we profit from the many years of experience gained with superconducting magnetic field sensors.

Exploded drawing of an OPM-based magnetic field camera for near field applications. It allows measurement of spatially resolved magnetic field distributions, e.g. emerging from small animals, with pT-sensitivity, mm-scale resolution at full-frame video rate. Each of the laser beams works as an individual OPM sensor pixel in the large, thin vapor cell.
Measurement setup containing head phantom and OPM sensor
OPM during field tests.

Research topics

  • Research on novel operating principles, operating modes and readout methods of OPM with respect to an optimization of, e.g., sensitivity and resolution down towards the quantum limit, accuracy,  sensor orientation and motion invariance or scalability to multi-channel systems,
  • Miniaturization and integration of sensors and arrays by means of functionalized alkali vapor cells manufactured on wafer scale using microfabrication technology and the use of compact optics and optoelectronics,
  • Development of tailored sensor systems for application scenarios in biophotonic imaging as well as geo- and environmental sciences on various platforms,
  • Research on innovative data processing and magnetic 3D inversion techniques.

Application fields

  • (Fetal) Magnetocardiography and encephalography,
  • Biophotonic magnetic field imaging, biosusceptometry,
  • Detection, localization and relaxometry of magnetic nano-particles,
  • Detection of magnetotactic bacteria,
  • Geophysical exploration: magnetic methods (vector magnetometry and full tensor gradiometry) and electromagnetic methods,
  • Physics beyond the standard model e.g. search for dark matter candidates, e.g., axions: OPMs in GNOME.
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