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Optical modes for quantum metrology and quantum information

Nicolas Treps

Mercredi 6 juin 2012

à 11h en salle C. Brot

From high sensitivity metrology to quantum information multiplexing, controlling the quantum state of light in all of its complexity is a route towards applications. Many approaches are under study, concerning the quantum states - single photons, gaussian states, squeezed states... - and the optical modes - frequencies, polarization, spatial modes, ...-. In our approach, we start from classically efficient configurations, where light beams are chosen intense to optimized signal to noise in the measurement. We then derive theoretically what are the fundamental limits to information extraction, and in particular which optical mode carries the noise -of classical or quantum nature- that limits sensitivity, and how these limits can be modified by proper light shaping. After a general introduction to the domain, I will show in some simple examples how these ideas can be implemented experimentally. Firstly, using spatial degrees of freedom of light I will show how to spatially shape both the classical mode -the image- and the quantum states to perform various tasks, from beam positioning to multimode entanglement for quantum information. Secondly, I will focus on spatio-temporal positioning using pulsed lasers - frequency combs -. I will show what are the fundamental limits in this problem, how they can be reached and why quantum approach is relevant for both metrology and quantum information processing.

Voir en ligne : Laboratoire Kastler Brossel