Ultracold Atoms for Quantum Sensors Now Also in Compact Devices

Researchers developed a portable way to produce ultracold atoms for quantum technology and quantum information processing, a scientific breakthrough that was published and featured on the front cover of Nature Nanotechnology.

The new technique is crucial for the measurement of atomic quantum states in compact devices, which is needed for a variety of practical applications, including quantum computers (and the all-knowing 'tricorder' scanning device from Star Trek...). For example, many of the most accurate measurement devices, including the atomic clocks needed for GPS satellites, work by observing how atoms transfer between individual quantum states. The highest precision is obtained with long observation times, often using slow-moving ultracold atoms that need to be prepared in a large apparatus.

But this could change now: "The longer the transition of atoms can be observed, the more precisely they can be measured. It is possible to shine laser light on atoms to slow them down using the Doppler effect. We can now do this in a really small device," explained Dr Aidan Arnold, a Lecturer in Strathclyde's Department of Physics

The researchers have developed technology which is far more compact than previous setups but can still cool and trap large numbers of atoms for use in portable devices. They pattern the surface of a semiconductor chip to form a diffraction grating, splitting a laser into many beams that cool the atoms.

The portable clocks, magnetometers and accelerometers that are made possible by this have wide-ranging applications, including navigation on earth and in space, telecommunications, geological exploration, and medical imaging, the scientists say:

"The miniaturization of atomic sensors using these optical gratings can make an important contribution to meteorology and high-precision measurement," said Dr Alastair Sinclair, Principal Scientist at the National Physical Laboratory.

Professor Charlie Ironside of the School of Engineering at the University of Glasgow said: "The specialized optical diffraction gratings were co-designed by the groups in the collaboration and some of them were microfabricated in the James Watt Nanofabrication Centre at the University of Glasgow - the work is a good example of how a team of physicists and engineers can collaborate to produce cutting edge technology."

The project was funded by the Engineering and Physical Sciences Research Council, ESA, the EU AQUTE project, the Wellcome Trust, the UK National Measurement Office, and the Royal Society of Edinburgh.