Protocol for rotation sensing with trapped ions provides blueprint for big sensitivity boost in a small package
Researchers in the USA have presented a protocol for a highly sensitive and compact gyroscope, capable of measuring very small changes in rotation. The design could form part of an inertial navigation system and offer directional information in the absence of GPS signals.
Full details and analysis of the gyroscope are published today in the Journal of Physics B: Atomic, Molecular and Optical Physics.
The proposed detection boost arises from the use of matter waves supported by an ion trap, but the operating principle is similar to fibre optic gyroscopes available today. Rotation is detected as a shift in the interference pattern generated inside the device.
“The matter wave will make lots of repeated round-trips in the ion trap, just like the light waves in a coil of fibre,” explained Wes Campbell of UCLA, who teamed up with colleague Paul Hamilton to carry out the theoretical study. “This is the key to shrinking down the device size.”
Matter waves – a description referring to the wave-like behaviour of atoms and other charged particles – allow extremely precise measurements of rotation to be made, but typically only when the interferometer track is spread out over a relatively large area.
What’s more, while gyroscopes based on photons (light) can have paths that loop around many times, there are fewer ways to achieve this with matter waves.
However, thanks to the use of an ion trap, which allows particles to bounce repeatedly back and forth, the scientists believe that the concept could be made to fit inside space craft or other vehicles that would benefit from navigation systems.
A prototype setup – centred around a vacuum chamber containing levitated atoms – would likely be the size of a dinner plate, but the researchers anticipate much smaller devices being possible further down the line.
The main application is navigation in an environment lacking GPS access.
“To complete the system, you’d also need linear accelerometers so you could record how far you’ve gone in each direction,” Campbell pointed out.
“But there may also be a clever way to perform that measurement using an ion – the possibilities of this system are almost entirely unexplored.”
The researchers reported their work in Journal of Physics B: Atomic, Molecular and Optical Physics. The article is published as part of a special issue on emerging leaders, which features invited work from the best early-career researchers working within the scope of the journal.
The special issue forms part of the Journal of Physics series’ 50th anniversary celebrations in 2017.