2013 Mott Medal and Prize
Dr Andrew James Shields, Toshiba Research Europe Ltd. For his research on semiconductor sources and detectors of quantum light states, as well as their application to secure communication on optical fibres, quantum-enhanced sensing and quantum computing.
Andrew Shields has pioneered research on semiconductor quantum photonics and its applications. In 2002 he led a team at Toshiba Research Europe and the University of Cambridge to demonstrate, the first voltage-powered source of single photons, based upon the electroluminescence of a quantum dot in a light emitting diode (LED),similar to those ubiquitous in TV remotes and traffic lights.
More recently Shields and his team demonstrated that LEDs can also create entangled light,another important resource for long-distance quantum communications and computing. This built on their earlier work showing the generation of polarisation entangled photon pairs from the biexciton state of a quantum dot. LED-like quantum light generators, which can be fabricated using conventional semiconductor techniques, may ultimately allow the exploitation of concepts in quantum physics in everyday life.
Semiconductor quantum photonics is today an extremely vigorous research field. Other important contributions by Shields and his co-workers include the generation of indistinguishable photons from different sources, essential for many quantum information applications, and voltage tuning of the correlations from entangled light sources. His work has contributed greatly to our understanding of excitonic effects and coherent dynamics in quantum semiconductors.
Shields has also been at the forefront of applications research in quantum photonics; leading efforts to realise single photon sources at fibre-optic wavelengths, and subsequently applying these to distribute secret digital keys by quantum cryptography. Other work extended the range of the technique to over 100 km of fibre for the first time. He invented a practical semiconductor photon detector, capable of registering up to 1 billion single photons per second, which has greatly enhanced the secure bit rate to over 1 Mb/s, enabling many new applications. Recently his team has demonstrated an application for entangled LEDs in electrically driven quantum teleportation.