PhD Project
Masters Project
Honours Project
Dr. Till Weinhold

Quantum communication is already the first commercial application of quantum technology allowing the secure sharing of secrets over a dedicated channel. However the achievable distances are limited due to the inability to build efficient quantum repeaters —systems that teleport the quantum state over multiple links. A central requirement for a repeater is the ability to temporarily and faithfully store the quantum state in a memory while waiting for the link to be established.  A very promising candidate for the storage of optically encoded information is the gradient echo memory (GEM) technique [1,2]. Due to its particular bandwidth and wavelength requirements, GEM has only been demonstrated with classical light fields and squeezed states, but not quantum information states.

Generating single photons matching these bandwidth requirements is the central focus of this project. After successful construction and characterization of the ultra-narrowband single photon source we will, in collaboration with the research group at ANU, test the operation of the GEM with genuine single photons, characterize its performance to store and retrieve quantum information states and establish long distance communication links.  

[1]Unconditional room-temperature quantum memory
M. Hosseini, G. Campbell, B. M. Sparkes, P. K. Lam and B. C. Buchler
Nature Physics, 7, 794 (2011)

[2] High efficiency coherent optical memory with warm rubidium vapour
M. Hosseini, B. M. Sparkes, G. Campbell, P. K. Lam and B. C. Buchler
Nature Communications 2,174 (2011)