Diamond sensor in cube highlights potential of quantum magnetometers
An imperfect diamond is perfect for detecting the Earth’s magnetic field from space.
A quantum device used defects in a diamond to map Earth’s magnetic field from the International Space Station. With only 10 centimeters on each side, OSCAR-QUBE reveals the potential of technology. He carried out consistently more than 10 months of data taking in 2021 and 2022, and its measurements agreed with a previous estimate of the magnetic field, engineer Jaroslav Hruby and colleagues report in a paper published May 7 in Applied physical examination.
Space-based measurements of the Earth’s magnetic field generally require large satellites. Quantum sensors can be smaller, while being more sensitive and operating more stably, among other advantages.
The OSCAR-QUBE sensor consists of a lens-sized piece of diamond with defects in its lattice of carbon atomsin which a carbon atom is missing and a neighboring carbon is replaced by a nitrogen. The defects act like quantum particles, with energy levels similar to those of an atom. Magnetic fields modify the energy levels of defects. This means that variations in the strength of the Earth’s magnetic field from place to place can be detected by measuring the light emitted when the diamond is hit with laser light and microwaves.
“The Earth’s magnetic field is actually very fascinating to measure, because it contains a lot of information,” says Hruby, of Hasselt University in Belgium. Movements inside Earth’s molten outer coreTHE rocks in the crustspace weather, and ocean tides all affect the magnetic field. Maps of the magnetic field can even be used to navigatefor example, when GPS is not available.
The performance of the device does not yet surpass that of the most advanced conventional magnetometers. But a future mission will have improved quantum hardware and take measurements from outside the space station, rather than inside, where internal magnetic fields limited its capabilities.
