School Seminar Program
Quantum memory for light: fun times with hot gas
Dr Ben Buchler
Department of Quantum Science
It is possible to store pulses of light in atomic ensembles. Provided this is done carefully, it is also possible to subsequently recall the light pulses while preserving their quantum state. This sort of optical quantum memory can then be used for a range of applications in quantum information systems, and in particular could be used to extend the range of quantum key distribution.
In this talk I will outline some of the schemes used for recording light into atomic ensembles and then focus on the experiments in the Department of Quantum Science that rely on a simple off-the-shelf gas cell filled with warm rubidium-87 vapour. Although quite low-tech, this system has shown the highest recall efficiency of any quantum memory. Our memory can also reorder the stored pulses of light, stretch or compress pulses, controllably change the pulse frequency and allow pulse splitting. All these properties and more can be explained graphically using a normal mode description of our system.
Dr Ben Buchler is a Future Fellow in the Department of Quantum Science. In 2002 he completed his PhD at the Australian National University on quantum measurement and control. From 2003 to 2005 he was a post-doctoral fellow at ETH Zurich in the nano-optics group where he worked on imaging the light-flow in photonic crystals and measuring single molecule fluorescence. Since returning to ANU in 2006 he has been working on atom-light interaction, quantum squeezing and quantum memory.