New Opto-Electronic Technologies for Photon Correlation Experiments

Iacopo Carusotto

In this Chapter, we give a brief review of the state of the art of theoretical and experimental studies of quantum fluids of light. Such systems consist of ensembles of photons that acquire a finite mass from spatial confinement or diffraction and finite binary interactions from the optical nonlinearity of the optical medium. The peculiar properties of these fluids are highlighted in comparison with standard condensed matter systems, with a special emphasis on the novel possibilities that they offer for the generation, the manipulation and the diagnostics of the fluid, as well as on their intrinsically non-equilibrium and/or dynamical nature. Perspectives towards a new generation of experiments on strongly correlated fluids of light and towards opto-electronic applications are finally sketched.

R. v. Baltz

Eli Yablonovitch, Hideo Kosaka, Hans D. Robinson +2 more

The transmission of quantum information over long distances will allow new forms of data security, based on quantum cryptography. These new technologies rely for security on the quantum "uncertainty principle" and on the long distance transmission of "quantum entanglement". A new type of tele-communications device called the "quantum repeater" can allow the faithful transmission of quantum information over worldwide distances, in spite of the inevitably severe losses while propagating along optical fibers. In a quantum repeater, information is stored in the quantum state of a semiconductor electron spin, while complementary entangled information is transmitted as a photon down the optical fiber. This long-range entanglement permits the execution of the teleportation algorithm, which accurately transmits a quantum state over long distances. The basis for an opto-electronic quantum repeater is an entanglement preserving InP photodetector with special selection rules, in which polarization information from a photon is transferred to spin polarization information of a photo-electron, and vice versa. Nevertheless, the algorithm requires that the photo-electron be transferred to a group IV semiconductor for long time storage since there is rapid loss of quantum information in III-V semiconductors. This paper reviews the experimental status of semiconductor quantum repeaters, including the spin resonance transistor logic gates, and the experimental detection of single photons in a manner that preserves their spin information.

E. G. Varona

A. Kanniainen, A. S. Kumar, A. Sammak +2 more

Spin of a donor bound electron in silicon has been shown to be a very coherent qubit system but lacks a coherent optical interface. There does, however, exist a donor bound exciton transition that can be excited optically but decays dominantly via an Auger recombination producing an electrical signal. This provides an opto-electrical pathway for spin readout. Scaling this readout to single-spin level will require interfacing the spins with silicon photonics for efficient guiding of photons, which in turn will require moving to silicon-on-insulator (SOI) substrates. Here we demonstrate first ensemble opto-electronic measurements of donor bound excitons in SOI material, including isotopically purified 28-Si device layers. The experiments show pronounced shifts in the resonance wavelengths and broadenings of the transition linewidths compared to the bulk experiments.

Alain Aspect