I am a Professor of Experimental Physics in the Quantum Optics and Laser Science (QOLS) research group of the Physics Department of Imperial College London. Until recently I was the Senior Consul at Imperial College London.
My expertise is in Atomic Physics, Spectroscopy and Quantum Optics. My current research is in the area of Trapped Ions and Laser Cooling (see the web page of the ion trap group).
We are the only research group in the UK working with laser cooled ions in a Penning trap. We trap individual atomic ions in our Penning trap and investigate how to laser-cool them to ultra-low temperatures where they essentially stop moving. We can then use them to study the interaction between laser light and individual particles, with applications in spectroscopy, quantum optics and quantum information processing. For a general review of Penning traps, see this article.
We have successfully cooled a single ion in a Penning trap to the ground state of its motion (in one dimension) 99% of the time. We are the only group to have demonstrated this technique in the Penning trap. We have also measured the heating rate in our trap to be one of the lowest of any ion trap in the world, thus demonstrating the potential of the Penning trap for experiments requiring long coherence times and low heating rates. A link to the publication describing this research is here. In our more recent work we have extended this technique to the cooling of both modes of motion of two ions in the trap, We have measured one of the lowest heating rates worldwide for the ion motion and have demonstrated a motional coherence time approaching one second.
We are now in a position to demonstrate manipulation of the motional state of the ion, and we have generated coherent states of motion with large amplitude in this way.
We are also now studying "Ion Coulomb crystals" which are formed when a small number of these ions are present in the trap. For a review of ion Coulomb crystals, see this article. The figure shows an experimental image of a crystal containing approximately 174 ions, together with a computer simulation of the crystal. Our research on this topic is described in this publication.
My teaching is mainly concentrated on Atomic Physics and Optics at Undergraduate and Postgraduate levels. I am currently coordinating and lecturing on an undergraduate Atomic Physics course and a course in Platforms for Quantum Technology for our Centre for Doctoral Training in Controlled Quantum Dynamics.
I was until recently Chair of the Science Studies Committee, which is responsible for approving courses and monitoring educational quality in the Faculty of Natural Sciences. .
I am active in the Institute of Physics as the former Chair of the Accreditation Committee. I have also been the Treasurer of the Higher Education Group.
I served as a member of the SPS and PS Experiments Committee at CERN, which reviews a large group of experiments using some of the accelerator facilities at CERN.
I was previously the Head of the Quantum Optics and Laser Science (QOLS) Research Group in the Physics Department and also the Director of Undergraduate Studies in the Department.
I have published the following books:
(Imperial College Press, 2014)
(Graduate textbook, World Scientific, 2016)
(Lecture notes, Imperial College Press, 2014)
et al., 2018, Sideband cooling of small ion Coulomb crystals in a Penning trap, Journal of Modern Optics, Vol:65, ISSN:0950-0340, Pages:64-74
et al., 2017, Sympathetic cooling in two-species ion crystals in a Penning trap, Journal of Modern Optics, ISSN:0950-0340, Pages:1-11
et al., 2017, High precision hyperfine measurements in Bismuth challenge bound-state strong-field QED, Nature Communications, Vol:8, ISSN:2041-1723
et al., 2017, Laser spectroscopy measurement of the 2s-hyperfine splitting in lithium-like bismuth, Journal of Physics B-atomic Molecular and Optical Physics, Vol:50, ISSN:0953-4075
et al., 2016, Resolved-Sideband Laser Cooling in a Penning Trap, Physical Review Letters, Vol:116, ISSN:0031-9007