Technology

Optically Pumped Magnetometer (OPM)

OPMs are passive magnetic field sensors, and they have three main components: (1) a laser, (2) a glass vapor cell containing ‘sensing’ atoms in a gaseous state, and (3) a photodetector.

 

f1-opm

 

Zero-Field OPM – Attributes: ultra-sensitive, works in low field environments, measures the vector components of the field
Zero-Field OPMs exhibit extreme sensitivity when the magnetic background is small. When the field is nearly zero, the atoms in the vapor cell become mostly transparent allowing maximum light onto the photodetector. Any change in the field induces a change in the transparency of the atoms. The resulting change in the photocurrent gives a measure of the magnetic field signal. Our ZF-OPM sensors measure field components along the sensitive axes and provide ultra-high sensitivity for detecting very weak magnetic fields, such as biomagnetic signals. [Detailed description]

Total-Field OPM – Attributes: very accurate, does not need calibration, works in earth field, measures the scalar amplitude of the field
Total-field OPMs can operate in Earth’s field with high accuracy.  The atoms in the vapor cell have a well-defined resonance frequency that is directly proportional to the magnitude of the field being measured.  Internal coils apply a varying RF field to resolve this frequency by monitoring the transmitted light through the cell. Resonance is achieved when absorption is maximized.  The output of the magnetometer is the value of this RF frequency, multiplied by a known scaling factor which directly converts frequency to magnetic field. Our total field magnetometer is well suited for applications in Earth’s field that require very high accuracy.

Key Innovations

  • Integrated design
    No fiber optics. The laser is directly integrated inside a unified sensor package, reducing vibrational and environmental sensitivity, and providing high performance even in the low-frequency band below 1 Hz.
  • Innovative Manufacturing
    Our unique manufacturing process allows for efficient, cost effective and scalable production of compact sensors.
  • Electronics and Software
    We’ve developed compact and high performance electronics that leverage the latest technologies for complete sensor operation and signal processing. Combined with our software, sensor operation is reduced to a few clicks of a mouse.