Enabling quantum technology
Technology based on laser-cooled atoms can be used in highly accurate, tamper-proof navigational systems, ultra-accurate clocks, or even to sense underground oil and mineral deposits. However, this requires atoms at temperatures that are a tiny fraction above absolute zero, trapped under ultra-high vacuum. This currently necessitates a lot of equipment, most of which is not portable.
At the University of Southampton, we are working on shrinking the ultra-high vacuum chambers needed to create ultra-cold atoms down from something the size of a fridge to a chip the size of a matchbox. In order to achieve this, we have taken a bottom-up approach and have had to push standard silicon manufacturing processes to their limits. Using electron beam lithography, deep millimetre-sized features have been successfully etched with nanometre precision; and using an ultra-high vacuum bonding machine, a vacuum chamber is being fabricated which measures just a few millimetres across. The rubidium atoms inside the chamber are cooled using a magneto-optical trap powered by a laser, which will eventually also be integrated into the chip.
Technological advantages of atom chips
- Cold and vapour phase atoms are the most sensitive detectors of magnetic fields, rotations, accelerations and gravity, as well as the tool at the heart of atomic clocks.
- Because the vacuum chamber is based on a passive design, it needs no pumps and therefore no power. The other components being integrated onto the chip, such as lasers, optics and detectors, will need power but we anticipate being able to use a battery to support the whole system, making it ideal for mobile applications.
Technology roadmap
While the physics behind cold atom sensors is mature, it is only recently that focus has been applied to unshackling them from the laboratory. This is part of the exciting new field of ‘quantum technology’. Initial work has been on identifying atom manipulation schemes suitable for miniaturisation and industrial applications. This will feed into designs that reduce the size and integrate the vacuum systems, pumps, atom sources and optics. More sophisticated devices will incorporate vias to power on-chip electronics and generate magnetic traps. In parallel, wavelength-stabilised laser systems for atom cooling and manipulation will be integrated using optical waveguide technology. On top of this, computer automation will be required to control the numerous sub-microsecond processes and data analysis.
Collaboration opportunity
We would like to hear from partners who are interested in sealed microlitre UHV devices, MEMS encapsulation, hermetic via technology, micro-optics, and ultra-stable integrated laser systems.
If you would like to know more, please contact Dr Matt Himsworth m.d.himsworth@soton.ac.uk
