Optical atomic clocks offer the potential for a new era of timekeeping, with laboratory systems at the world’s leading NMIs already demonstrating 100x improvements in accuracy compared with the microwave fountain clocks that offer the best realisations of the SIsecond. Enhanced PNT systems with these next-generation clock technologies could facilitate GNSS constellations with significantly- reduced positioning errors and improved holdover resilience. However, these clocks require ultra-stable lasers to interrogate the optical atomic clock transition. One way to achieve this is to pre- stabilise the lasers to a high finesse optical cavity using the Pound-Drever-Hall technique.

In this LS-OCCU project, the National Physical Laboratory (NPL) will develop a portable dual axis cubic optical cavity and digital control electronics to pre-stabilise not only the clock laser, but also the cooling and other auxiliary lasers required for future space-based strontium ion or neutral strontium lattice optical clocks, in a single high vacuum package. This system offers a compact low size, weight, and power (SWaP) arrangement while being sufficiently robust to withstand the harsh environmental conditions typical of launch and spaceflight.


*Note: the picture is credited to NPL