Atom trapping tractor beam could herald new era of quantum capabilities

University of Adelaide researchers have created a tractor beam that traps atoms, a development that could herald a new era of quantum sensing capabilities.

quantum sensing
Dr Philip Light with the atomic chamber in which the atomic tractor beams were created

According to the University, the tractor beam – or light-driven energy trap – pulls atoms into a microscopic hole at the centre of an optical fibre, opening the way for new quantum experiments that could lead to new secure communications or advanced sensing technologies.

Published in Physical Review Applied, the researchers from the University’s Institute for Photonics and Advanced Sensing (IPAS) said this is the first time that scientists have been able to demonstrate a highly efficient ‘waveguide trap’.

Ashby Hilton, the PhD student who developed the technology, said: “The trap is made of invisible infra-red light. The beam grabs hold of atoms that are floating in a chamber that is almost completely emptied of gas.

“Every atom that enters the tractor beam is pulled into the fibre – there is no escape. And once sucked into the interior of the optical fibre the atoms can be held for long periods of time. Our experiments show that we can very precisely control light to produce exactly the right conditions to control atoms.”

The tractor beam works by the infra-red light interacting with the atoms to create a change in energy which drives the atoms to the most intense part of the light beam.

Quantum sensing

Lead researcher Dr Philip Light said: “What is really exciting is that now we have the possibility to do quantum experiments on these trapped atoms. Our first experiments intend to use these stored atoms as elements of a quantum memory. We hope that our work may eventually form part of absolutely secure communications channel that is of obvious high interest to defence, intelligence and industry.”

The researchers are now said to be moving onto the next stage in which the tractor beam is formed from a hollow cone of light rather than a solid beam of light. In this new configuration the atoms will be held at the centre of the light cone where it is perfectly dark.

“This is an extremely powerful idea – we can move and manipulate the atoms, but are able to shield the atoms from the disruptive effect of intense light,” said Dr Light. The researchers have essentially created a quantum funnel which allows them to guide and trap atoms for longer without disrupting their delicate quantum state.

IPAS director Prof Andre Luiten said: “Our researchers are manipulating and measuring individual atoms and molecules to sense the world around us. This new era of quantum sensing is opening up diverse new possibilities from attempting to detect disease through finding particular molecules in the breath, to assisting miners and defence by detecting anomalous magnetic fields associated with mineral deposits or covert submarine activity.”

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