Magnetic Field Measurement – Quantum Sensing

Researchers have developed a new method for atomic-scale magnetic field measurement with high precision, both up and down and sideways. The new tool helps map the electrical impulses inside a firing neuron, characterize new magnetic materials and investigate exotic quantum physical phenomena.

The technique builds on a platform already developed to probe magnetic fields with high precision using nitrogen-vacancy (NV) centers, which are tiny diamond defects. These flaws are two adjacent places in the diamond’s orderly lattice of carbon atoms where carbon atoms are missing; one is replaced by a nitrogen atom, while the other is left empty. It results in missing bonds in the structure and electrons extremely sensitive to small changes in their environment, whether electrical, magnetic, or light-based.

Previous applications of single NV centers for magnetic field measurement were extremely precise but only detected variations along a single dimension aligned with the sensor axis. However, for some applications, such as mapping out the connections between neurons by measuring the exact direction of each firing impulse, measuring the sideways component of the magnetic field would also be helpful.

Essentially, the new method solves the problem by utilizing a secondary oscillator provided by the nuclear spin of the nitrogen atom. The sideways component of the field to be measured nudges the secondary oscillator’s orientation.

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