Technology
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Researchers at Wuhan University (WHU) in China have produced a commercially manufacturable atomic clock less than one-seventh the size of its smallest US counterpart for use in satellites, drones and other technologies that need precise timekeeping.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.As reported in the South China Morning Post, this might be the smallest miniature, or chip scale, atomic clock ever produced at scale. It is a little cube with a volume of 2.3 cubic centimeters, slightly over half the volume of a standard 16 millimeter six-sided die.
While there has been a lot of focus on optical atomic clocks, the next generation of these devices that can be hundreds of times more precise than standard atomic clocks, this device is more of an innovation on the classic design and doesn't use the newer technology.
“WHU's team has created the world's smallest Chip Scale Atomic Clock (2.3cm³), with just 1 second of error in over 30,000 years. This low-power, high-precision clock is mass-produced and used in low-orbit satellites, underwater #BeiDou navigation systems, and other key fields,” the University posted in a Facebook post.
In space, GPS satellites – such as those operated by BeiDou, the Chinese satellite navigation system – use atomic clocks. But precise timekeeping in miniaturized form is useful in many other situations. Drone flying, for example, requires very precise clocks.
The new device differs from standard cesium atomic clocks because it doesn't require a resonant cavity to maintain its tick. You can't make a resonant cavity arbitrarily small, which gives a fundamental limit to the minimum volume. The US Chip Scale Atomic Clock, which is around 17 cubic centimeters, still uses cesium, with a low-powered laser to determine the specific frequency used to keep the time.
The Chinese researchers used a similar approach but went even smaller, producing a tiny cell containing atoms of an alkali metal (it is unclear whether it is still cesium) that are excited by a semiconductor laser. It isn't as precise as conventional atomic clocks, but it is still thousands of years ahead of standard timekeepers.
“Even if traditional atomic clocks are miniaturised, the minimum volume limit is still several hundred cubic centimetres and the minimum power consumption is at least several watts,” research lead Professor Chen Jiehua told Changjiang Daily.
“Thanks to its compact size and low power consumption, this new product holds broad market prospects.”
The clock has been in production for a while, and the team has now founded a company to produce it at scale. Several hundred units were produced in 2024, but production rates could be increased by reducing the cost and overcoming technical challenges in production.
[h/t: South China Morning Post]
