3D printed surfaces help atoms play ball to improve quantum sensors

Scientists have created 3D printed surfaces featuring intricate textures that can be used to bounce unwanted gas particles away from quantum sensors, allowing useful particles like atoms to be delivered more efficiently, which could help improve measurement accuracy.

The researchers from the University of Nottingham’s School of Physics and Astronomy created intricate, fine-scale surface textures that preferentially bounce incident particles in particular directions. This can help to keep unwanted particles out of the way. The team demonstrated this by applying it to a surface-based vacuum pump and tripled the rate at which it removed nuisance gas particles. 

The research - Exploiting complex 3D-printed surface structures for portable quantum technologies, has been published today in the journal Physical Review Applied. 

Quantum sensors use microscopic quantum objects to measure magnetism, gravity and other effects with unprecedented precision. They are set to revolutionize medical diagnostics, navigation and scientific research. The extreme sensitivity of these quantum objects means that they mustn’t be bumped or jostled by air molecules, so they only work under vacuum. The air around us is dense enough that gas particles bump into each other all the time, but in a strong vacuum particles can travel meters or even kilometres before hitting another gas particle.

Controlling high-vacuum gas dynamics is critical to ensure the accuracy of measurements and although quantum sensors typically operate in highly controlled, strong vacuums, undesirable particles still occasionally get in and introduce noise.

To combat this the Nottingham team created an ice hockey puck-sized system by 3D printing titanium alloy into different patterned surfaces—hexagonal pockets and conical protrusions—designed to increase the number of times an incident atom made contact with the surface. The system fits into the ports of a commercial vacuum chamber. 

Nathan Cooper, Research Fellow in the School of Physics and Astronomy and lead author on the paper said: “We are still discovering the most effective surface textures; promising candidates include a hexagonal pattern similar to a honeycomb and an intricate three-dimensional pattern derived from geometry-inspired artwork. This relatively low-tech innovation can substantially improve advanced quantum technologies.”

The authors tested how strongly the structured surfaces could enhance surface-based vacuum pumps, measuring up to 3.8 times the pumping rate per unit area for the samples tested. Simulations have found achievable surface patterns that may offer up to a ten-fold increase.

PhD student, Ben Hopton, co-author on the paper said: “What’s exciting about this work is that relatively simple surface engineering can have a surprisingly large effect. By shifting some of the burden from active pumping to passive surface-based pumping, this approach has the potential to significantly reduce, or even remove, the need for bulky pumps in some vacuum systems, allowing quantum technologies to be far more portable.”