2008 Young medal and prize

Professor Patrick Gill

The National Physical Laboratory

For world leading contributions to optical-frequency metrology.

The Young medal and prize for distinguished research in optics including work related to physics outside the visible region has been awarded to Professor Patrick Gill, Senior NPL Fellow and Head of Optical Frequency Standards at the National Physical Laboratory, for world leading contributions to optical-frequency metrology.

Professor Gill is recognised as the UK leader in the quest for very accurate optical clocks. Following experiments on laser stabilisation, in 1985, he achieved at NPL the first laser-cooling of trapped ions in the UK, subsequently developing frequency standards based on quantum transitions in single, cold ytterbium and strontium ions that absorb and emit at optical wavelengths.

Gill’s group was the first to observe a so-called octupole transition in a single ytterbium ion - in some ways, the ultimate optical clock transition because of its extremely long-lived excited state. Because the transition frequency is extremely weak, it was difficult to detect but the team was able to locate it by first measuring the frequencies of related, stronger transitions. The work was cited by the American Physical Society as one of the ‘Discoveries of the Year’.

Gill was also one of the very early developers of the frequency-comb idea, whereby the ultrafast laser pulses are used to generate a set of sharp, narrow frequencies which act as an ‘optical ruler’, and can be used to link optical transitions directly to the microwave transitions used in atomic clocks. In 2004, he led a tour de force experiment where the femtosecond laser frequency comb measured the prototype optical clock frequency, based on a strontium-ion optical transition, with accuracy close to the capability of the best caesium microwave clocks.

Professor Gill’s work in these areas has established NPL within the top four frequency standards and metrology laboratories in the world.