New Invention: cold-atom source for quantum technologies

20 June 2018

Pyramidal magneto-optical trap

Oxford Physics researchers have designed a compact magneto-optical trap with identical mirrors and mounts, making it easier to manufacture and fit inside a standard size vacuum tube.

Unlike previous devices, the size of the hole through which the atoms emerge is adjustable; this adds the ability to change the divergence of the beam of cold atoms to meet the requirements of different users. The divergence of the beam of cold atoms depends on the geometry i.e. distance from the centre of the applied magnetic field to the hole, and the hole size. The hole also determines the effectiveness of the difference pumping between the source and the vacuum chamber to which it is attached. Different users will have different requirements for the amount of background gas/contamination that is acceptable. This all means a single specification of a device could be provided to multiple users and still meet their differing requirements.

Operating principle

Laser cooling is a well-established technique (Nobel Prize in Physics, 1997). The force exerted on atoms by laser light of a particular frequency in a configuration of mostly counterpropagating beams can reduce the atomic velocity to the equivalent of a temperature of a few microkelvin. At these temperatures, the atoms are moving extremely slowly which permits very precise measurement. Ultracold atoms have a variety of applications in quantum technology, including atomic clocks and interferometric sensing.

Atomic clocks

Precise clocks are essential for the synchronisation of electronic communications systems and precision positioning by satellites (GPS). Timekeeping is referenced to the primary standards of time maintained at national laboratories where the next generation atomic clocks based on laser-cooled atoms is almost 100 times better than what was previously available. It is important to have secondary clocks distributed throughout the networks that can continue providing accurate synchronisation in the absence of satellite signals. Such resilience is increasingly important as more and more infrastructure becomes dependent on GPS for its operation. The compact cold-atom source is suitable as an OEM component of such systems.

Atom interferometers

As well as the precise measurement of time, cold atoms give great improvements in the determination of gravity and sensing of rotation using the interference phenomena in the vertical and horizontal planes respectively. The atoms are considered as matter waves rather than particles. Gravimeters can be used for surveying the underground structures, e.g. detecting hidden voids prior to construction.

Cold-atom sources for the scientific market

The large-scale investment in quantum technologies in the UK and EU has stimulated the establishment of many research teams in industry and academia. The compact cold-atom source provides rapid set up and high reliability for these users.

Visit Oxford University Innovation for more information about licensing this technology.