The NPL Time & Frequency group has long-standing experience in the development of ultra-stable lasers and high-accuracy cold atom and ion microwave and optical clocks. Our laboratory based cold atom and ion optical clocks have demonstrated accuracies in the region of a few parts in 1017 to few in 1018. As part of a programme to develop compact optical clocks, NPL has designed a novel cubic cavity that has a very low sensitivity to vibration (<2 x 10-11/g). This patented design is being developed for future space applications in areas such as future generation GNSS, telecommunications, relativistic geodesy, earth observation (gravity mapping) and fundamental physics. Further, we have developed infra-red frequency references for space-borne climate change studies.
