Semiconductor Devices for Quantum Information Applications

Andrew J. Shields (1)

co-authosrs: R.M. Stevenson (1), J.Nilsson (1), C.L. Salter (1,2), A.J. Bennett (1),  R.B. Patel (1,2), M.A. Pooley (1,2), D.J.P. Ellis (1), A. Boyer de la Giroday (1,2), N. Skold (1), A. Schwagmann (1,2), S. Kalliakos (1), I. Farrer (2) and D.A. Ritchie (2)

(1) Toshiba Research Europe Limited, Cambridge, U.K.
(2) Cavendish Laboratory, Cambridge University, Cambridge, U.K.

Light Emitting Diodes containing a self-organised quantum dot as the emissive element may be used to generate single photons, as well as polarisation-entangled pairs.  Electrical injection of the recombining carriers has the advantage of negating the need for a pump laser and its awkward alignment with the dot, while potentially also allowing individual devices to be addressed in a quantum integrated circuit.  Moreover, the contacts may also be used to control several aspects of the emission.  For example, using sub-nanosecond voltage pulses it is possible to coherently control the dot states, allowing the wavefunction of the emitted single or entangled pairs to be manipulated.  Furthermore, indistinguishable photons may be generated from different dots, a prerequisite for scaling photonic approaches to quantum information processing, by tuning the emission wavelength of each dot with an applied voltage. Recent progress in using semiconductor devices for quantum communications and quantum logic gates will also be presented.