Sinclair, Neil

Date:  Monday, March 6, 2017
Time: 11:15
Place: ETH Zurich, Hönggerberg, HPF G 6
Host:  Atac Imamoglu, Christian Degen

Rare-earth-ion-doped crystals for future quantum technology

Neil Sinclair
University of Calgary, Canada

Rare-earth-ion-doped crystals have long been known to possess many favorable properties at cryogenic temperatures. This has spurred the development of these crystals for various applications of quantum science, with particular emphasis on quantum memories for quantum repeaters. In this presentation, I summarize the research being performed using rare-earth-ion-doped crystals at the Quantum Cryptography and Communication Laboratory in Calgary, Canada.

I will discuss work employing a thulium-doped lithium niobate waveguide. We have recently shown that this waveguide, which is fabricated by the indiffusion of titanium into thulium-doped lithium niobate, has spectroscopic properties that are equivalent to those of a similar unmodified bulk crystal. These results refute previously held beliefs that crystal modification comes at the expense of deteriorated properties. Next I outline a scheme for quantum repeaters that benefits from the large bandwidths provided by the inhomogeneous broadening of rare-earth-doped ensembles and show results from a proof-of-principle experiment using the thulium-doped lithium niobate waveguide. Furthermore, I illustrate how this waveguide can be used to perform quantum signal processing tasks, including quantum non-destructive measurements of qubits.

Finally, I discuss work towards a quantum memory at 795 nm that features storage times of hundreds of microseconds, an experiment where we demonstrate entanglement between more than two hundred ensembles of rare-earth ions, the development of the first waveguide quantum memory at telecom wavelength, and experiments towards entangling two different solid-state quantum memories.