Past events

Photonic quantum technologies: Metrology, Spins and Photons

Prof J.G. Rarity, University of Bristol

Part of the Zepler Institute Quantum Technologies Lecture Series


In Bristol, we are researching the full range of applications of photonic quantum technologies including quantum communications, quantum measurement and quantum information processing. In this talk I will review the wider Bristol work and then focus on three topics that are my key interests.

The first is sub shot noise transmission measurements using commercial camera technologies where we have demonstrated record 'absolute' noise reductions and have begun scanned imaging experiments using a CCD to measure heralded photons.

The second topic is the development of spin-photon interfaces using cavity QED in the 1D limit. I will describe the progress towards 1D cavities containing single emitters focusing on our work with quantum dots and colour centres in diamond. Both systems exhibit ground state spins that lead to spin dependent transitions and the potential to entangle ground state spin with emitted or reflected photons. Spin-photon entanglers are effectively universal and deterministic quantum gates enabling quantum memories, quantum repeaters and eventually large-scale quantum computation.

The third topic focuses on using the ground state spin in NV-centres used as electric field and/or nuclear magnetic field sensors stimulated by the difficulty of fabricating cavity structures coupled to NV-centres. In particular, we are perfecting a strain sensing technique using the ground state spin hyperfine split by the local nitrogen 14 nucleus.

Short bio

John Rarity pioneered the experimental one-photon and two-photon optics, both to the study of fundamental physical phenomena and also in the development of prototype devices. This requires specially designed sources and detectors, the former including parametric down-conversion and single-defect emitters. Rarity has made leading advances both to detector design and to such exotic sources and was, with his collaborators, for many years the sole UK representative in experimental quantum optics, his research telling us much about the nature of photons. He spotted early the potential for experimental quantum information and has become a leading figure in this field.