26 September 2013 Quantum information theory

Measurement of the relative misalignment between two distant reference frames using entangled photons

Photonic polarization gears for ultra-sensitive angular measurements in Nature Communications. ICFO researcher Leandro Aolita, in collaboration with researchers from Sapienza Università di Roma, Università di Napoli, Universidade Federal do Rio de Janeiro, and the Centre for Quantum Technologies of Singapore, has recently reported in Nature Communications on the experimental demonstration of ultra-sensitive photonic angular sensors. Their method possesses two remarkable properties: i) It renders a sensitivity enhancement of two orders of magnitude with respect to the current state of the art; and ii) it is robust against photon loses. Thus, it lifts some of the more stringent requirements for practical high-precision angular measurements with photons.

The sensors consist of special quantum states called \"photonic gears\", which are entangled in the polarization and orbital angular momentum degrees of freedom. These are created and detected using a novel liquid-crystal device, called the q-plate, which allows for the efficient manipulation of high total (polarization + orbital) angular momentum components. The technique has potential for industrial applications, as well as for quantum metrology and fundamental tests of quantum theory.

Until recently, Dr. Leandro Aolita worked as a postdoctoral researcher in the “Quantum information theory” group at ICFO led by Prof. Antonio Acín. He is currently a Marie Curie fellow in the “Quantum many-body theory, quantum information theory, and quantum optics” group at the Free University of Berlin.

Dr. Aolita will be visiting ICFO next Tuesday, October 1st, to give the talk ‘From Misalignment-Immune Flying Qubits to Ultrasensitive Angular Sensors: Playing with Polarisation and Orbital-Angular-Momentum Photonics Gears’, where he will explain the scientific results obtained from this study.