BIPM150 Poster Session: Rubidium for Precise Atomic Clocks
As the world becomes ever more dependent on technologies that require ultra-precise timing—from navigation satellites to medical systems—the science behind atomic clocks is evolving.
At the BIPM’s Scientific Symposium held during the 150th Anniversary of the Metre Convention, Dorothy Mringie from the State Department of Trade, Kenya presented a poster entitled “Triple Resonance of Rb for Atomic Clocks and Quantum Metrology.”
Co-authored with Geoffrey Rurimo Kihara and Elijah Ogaro Nyakango of National Institute for Optics and Lasers (NIOL) Kenya, the poster explores how the alkali metal rubidium can be used to build accurate, affordable national time and frequency standards through saturated absorption spectroscopy.
As part of this proposal, the poster highlights how triple resonance spectroscopy (N-type system) can be used to overcome limitations seen in double resonance methods. By introducing a third laser to repopulate atoms lost to dark states, this technique improves the figure of merit of rubidium’s spectral lines—enhancing their resolution and overall clarity—by reducing linewidths from over 28–30 MHz to just 7–8 MHz in simulations.
This enhanced resolution is vital for applications in atomic clocks and quantum metrology, and further strengthens rubidium’s potential as a viable, accessible timekeeping standard.
Atomic Clocks – The Basics
Atomic clocks work by locking onto the highly stable frequencies generated by atoms, such as rubidium or caesium, as they respond to light. These frequencies serve as reference points for measuring time.
Saturated absorption spectroscopy is a technique used to detect and stabilize these reference frequencies. It allows scientists to detect the tiny shifts in energy levels that atoms like rubidium display when exposed to laser light. These shifts reveal a highly stable natural frequency — like a reliable atomic ‘tick’ — which is then used to regulate the timing system in the clock.
The Poster
Listen to a 2-minute audio recording of Ms Mringie explaining their poster, here.
Beyond its technical contributions, Ms Mringie’s presentation highlighted the value of rubidium as a more accessible and commercially available element for atomic clocks. By lowering the financial and logistical thresholds for participation, its use may support greater involvement in international time and frequency science — particularly in countries where national timekeeping capabilities are still being developed.
This poster reflects a growing recognition within the global metrology community of the need to support inclusive participation and strengthen regional expertise as part of a resilient international measurement system.
Watch Dorothy’s Presentation
BIPM150: Nine Standout Scientific Posters
Chosen from nearly 400 submissions received from around the world, these standout posters address some of the most pressing challenges in modern metrology—from quantum technologies and digital transformation to health, education and sustainability.
Each of these 9 posters was selected by the BIPM Poster Committee from one of nine key topic areas, reflecting the breadth and innovation driving the global metrology community. Learn more.