New atomic clock technology will improve GNSS location accuracy, as well as addressing the scalability of other quantum technologies being developed

Nanofabrication experts Kelvin Nanotechnology have teamed up with product design specialist Wideblue, the University of Strathclyde and the University of Birmingham on a UK Research and Innovation  (UKRI) project funded by the Industrial Strategy Challenge Fund to develop innovative techniques in the miniaturisation of optical atomic clocks.

The new clock technology will help improve GNSS location accuracy, as well as addressing the scalability of other quantum technologies being developed by the academic partners.

“Small, low cost atomic clocks will be essential as we develop a resilient position, navigation and timing (PNT) infrastructure to support our financial, power distribution and communications services,” said Roger McKinlay, challenge director – Quantum Technologies at UKRI.

Cold atomic samples have led to profound advancements in precision metrology by measuring the frequency separation of discrete atomic energy levels. These atomic clocks are the ultimate timekeepers, with the state-of-the-art instruments providing a timing accuracy that it would neither gain nor lose a second in over 30 million years.

Because of the high level of accuracy in these instruments, atomic clocks are used to coordinate systems that require extreme precision, such as GNSS. Each satellite network contains multiple atomic clocks that contribute precision timing data, which is decoded to provide location data by effectively synchronizing each receivers’ atomic clocks with those of the satellite.

“The project is a feasibility study which aims to facilitate the miniaturization of state-of-the-art atomic clocks.” said Russell Overend, managing director of Wideblue. “To achieve such high timing resolution, the atomic clock makes use of ultra-narrow transitions in strontium atoms, providing orders of magnitude better performance than their rubidium counterparts due to narrower atomic features. In simple terms, the narrower the atomic transition the more accurate the atomic clock.

At Strathclyde, cold atom clock experiments are aided by expertise in grating magneto-optical traps (gMOTs), illustrated here. (Image: Aidan Arnold, University of Strathclyde)

An important factor in cold atomic clock technology is grating magneto-optical traps (gMOTs). With gMOTs, diffraction gratings split and steer an incoming beam into a tripod of diffracted beams, allowing trapping in the four-beam overlap volume. 

Wideblue will develop the optical system that will deliver the laser light onto the gMOT chip. Kelvin Nanotechnology will manufacture the gMOT and compact collimation optics designed by Wideblue. The University of Strathclyde will design the gMOT chip, and the University of Birmingham will perform the testing of the prototype optical system.

“Atomic clocks are an integral component in modern technology and impact our daily routines from computing and financial transactions to the navigation systems we use in our phones and cars,” said James McGilligan, Kelvin Nanotechnology, “As state-of-the-art atomic clocks push new boundaries in precision measurement, we face a new challenge of bringing this complex and large physical apparatus into a compact and user-friendly system where we can make the largest societal and economic impact.

“Our current collaboration with Wideblue and our academic partners aims to address the scalability of one such atomic clock by reducing the optical constraints into scalable micro-fabricated components as a critical step to bringing laboratory performance out into real world applications,” McGilligan said.

“With support from the Quantum Technologies Challenge in UKRI — part of the UK National Quantum Technologies Programme — we are ensuring that the UK economy and society will benefit from the next generation of quantum devices and be quantum ready,” McKinlay said.