Timing is everything in modern warfare, where even a nanosecond’s delay can make the difference between hitting or missing a target in a coordinated drone or missile attack.
China may now have taken a major step forward in this field with the mass production of the world’s smallest atomic clock – something the researchers behind it say could transform drone warfare, underwater navigation and battlefield communication.
Developed by a research team led by Professor Chen Jiehua from Wuhan University’s Satellite Navigation and Positioning Technology Research Centre, the clock only loses a second every 30,000 years, according to the official newspaper Changjiang Daily.
The device measures just 2.3 cubic cm (0.14 cubic inch), less than one-seventh the size of the leading US models and about the size of a fingernail.
“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,” Chen told the newspaper.
According to Chen, the US has produced a 17 cubic cm product, but his team’s clock has a comparable performance even though it is much smaller.
“We have achieved mass production of chip-scale atomic clocks, successfully applying them to time synchronisation systems such as micro-PNT [positioning, navigation and timing], underwater BeiDou [China’s equivalent of GPS], low-orbit satellites and drone swarms.
“Thanks to its compact size and low power consumption, this new product holds broad market prospects.”
The miniaturisation is possible because the team uses a quantum optical phenomenon known as coherent population trapping, rather than the microwave cavity technique used in earlier atomic clocks.
In conventional atomic clocks, microwaves interact with atoms in a resonant cavity to generate a stable frequency reference, but this imposes physical limits on how small the device can be.
But coherent population trapping clocks have a tiny cell containing alkali atoms, such as rubidium, and use two frequencies generated by a modulated semiconductor laser.
When the frequency difference between the two optical fields exactly matches the energy gap between two atomic ground states, the atoms enter a special quantum condition called a “dark state”.
In this state, the atoms stop absorbing light and a narrow transmission peak appears in the optical signal that provides a stable frequency reference.
Because the signal is generated using compact lasers and microfabricated vapour cells, the entire atomic clock can be integrated into a chip-scale system, dramatically reducing its size and power consumption.
Members of the research team have now founded a spin-off company, Taifs (Wuhan) Technology Co, backed by the state-owned Yangtze River Industry Group, to produce the clocks at scale.
According to Changjiang Daily, the company sold several hundred units in 2024, with demand expected to surge.
Yet challenges remain. The high cost and performance demands of the specialised lasers still limit mass adoption, but Yangtze River Industry Group hopes to use its financial muscle to help Tafis overcome the problem.
“Yangtze River Industry Group is leveraging its financial and resource advantages to assist enterprises in overcoming key technical challenges in core components and promoting automated mass production to reduce costs,” Gou Fei, the investment director at Changjiang Beidou, a Yangtze River Industry subsidiary, told the newspaper.
“In the future, as costs decrease, chip-scale atomic clocks will achieve broader applications in military and civilian communication fields.” -- SOUTH CHINA MORNING POST
