Diamond sensor picks up the heart's magnetic signals express
A tiny defect in diamond is like a microscopic ear, able to pick up the magnetic 'breath' of the heart. Such sensors work at room temperature and are no bigger than a grain of sand.
To hear a faint signal in a noisy room, engineers used two sensors: just as our ears compare sound to discern speech, a pair of diamond 'ears' subtracts the magnetic background. This made it possible to record a magnetocardiogram without bulky shielding.
The irony is that the sensor is not a perfect diamond, but its flaw — a nitrogen atom next to a vacancy in the lattice. It is precisely this defect that, under the light of optical spectroscopy, turns into a supersensitive element. In the future, such sensors could form the basis of contactless diagnostic patches — cheaper and more portable than traditional magnetometers.
The heart's magnetic pulse was first captured in 1963—the setup was the size of a car and required expensive magnetic shielding.
The medical tricorder from Star Trek is closer than it seems: a compact diamond sensor reads magnetic rhythms without contact.