A team of physicists at the University of Nottingham have shown that 3D printing parts for ultracold quantum experiments allows them to reduce the size of a device to one-third of its normal size. Their work is published in the journal Physical Review X Quantum.
Scientists’ development opens up access to a faster and more convenient way to create smaller, more stable, customizable setups for quantum experiments. Today, physicists use laser light and magnets to synthesize ultracold atoms. And the resulting atoms are used, for example, to identify even the weakest magnetic fields or create clocks with an accuracy of a quadrillion second. Therefore, physicists have long sought to use devices with ultracold atoms in a variety of conditions, from space exploration, where they can aid navigation, to hydrology, where they can pinpoint the location of groundwater by detecting its gravitational pull. But the very process of cooling atoms enough to accomplish any of these tasks is often complex and difficult.
The key to cooling and controlling atoms is hitting them with finely tuned laser light. Hot atoms move at hundreds of kilometers per hour, while extremely cold atoms are almost motionless. Physicists make sure that every time a laser beam hits a warm atom, the light falls on it in such a way that the atom loses some energy, slows down and becomes colder. Scientists usually work on a laboratory bench measuring 1.5 m by 2.5 m, on which there is a “labyrinth” of mirrors and lenses – optical components that control light. To control where all the ultracold atoms are in this chamber, physicists use magnets: their fields act like “fences.”
Compared to particle accelerators several kilometers long or large telescopes, these experimental facilities are small. However, they are too large and fragile to be commercialized and applied outside of academic laboratories. Physicists often spend months aligning every little element in their optical labyrinths. Even the smallest shaking of mirrors and lenses – which can happen in the field – will result in significant delays. So the Nottingham researchers turned to 3D printing.
The physicists’ installation takes up less than 0.15 cubic meters of volume, which is slightly more than a stack of 10 large pizza boxes. “This is very, very little. We’ve reduced the size by about 70% compared to the conventional setup, ”says Somaia Madhali, a Nottingham graduate student and first author of the study. To build it, she and her colleagues assembled their rig from blocks that they 3D printed. Rather than machining a vacuum chamber out of tough but heavy metals, the team printed it out of a lighter aluminum alloy. And they inserted lenses and mirrors into a holder, which they also printed from polymer.
The resulting miniature setup worked successfully. The team loaded 200 million rubidium atoms into their vacuum chamber and sent laser light through all the components of the optics, causing the light to collide with the atoms. The atoms formed a sample with temperatures below –267 degrees Celsius — just as scientists have done with more traditional instruments for the past 30 years.
The big advantage to using 3D printing is that scientists can design each component individually. Therefore, the new research is a step forward in making this basic physics research tool more accessible and commercially available. Physicists speculate that such instruments will be used outside of academia, for example by companies making quantum sensors that sense magnetic or gravitational fields.