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Quantum Nonlinear Optics Using Quantum Memory

Speaker: Prof. Ping Koy Lam Australian National University
Time: 2014-04-04 10:00-2014-04-04 11:00
Venue: FIT 1-222


Large nonlinearity at the single-photon level can pave the way for the implementation of universal quantum gates. However, realizing large and noiseless nonlinearity at such low light levels has been a great challenge for scientists in the past decade. We present a proposal for using quantum memory to enhance the cross-phase modulation (XPM) of two optical fields. Our memory, which is based on the gradient echo memory (GEM) scheme, maps the optical fields into Fourier transformed polaritonic excitations in an atomic ensemble. We show that nonlinear interactions can be induced in GEM. Due to the slowing down and subsequent storage of light fields within a memory, nonlinear interaction time between the fields can be extended resulting in an enhancement of the effective nonlinearity. We present results showing noiseless cross-phase modulations and discuss plans to further increase the cross-phase modulation strength to a level useful for implementing quantum gates.

Short Bio:

Ping Koy Lam completed his degree with a double major in Mathematics and Physics from the University of Auckland in 1990. He worked as a process engineer for Sony (Audio Electronics) and Hewlett-Packard (Semiconductor LED) for 3 years prior to his post-graduate studies at the ANU where he obtained a Masters in theoretical physics, and a PhD in experimental physics. He was awarded the Australian Institute of Physics Bragg Medal and the ANU Crawford Prize for his PhD in 1999. He was an Alexander von Humboldt fellow at the Erlangen-Nürnberg Universit?t in 2000 and a CNRS visiting professor at Paris University in 2007. He was awarded the 2003 British Council Eureka Prize for inspiring science (Quantum Teleportation) and the 2006 UNSW Eureka Prize for innovative research (Quantum Cryptography). Ping Koy is the chief scientist and co-founder of QuintessenceLabs Pty. Ltd, a spin-off company of his group that commercialises quantum communication technology, and professor of Physics at the Australian National University.

Ping Koy’s research interests include quantum optics, optical metrology, nonlinear optics and quantum information. Within the Centre for quantum computation and communication technology, he manages the ANU node and is the quantum communication work package leader. His research covers quantum key distribution, quantum memory, quantum repeater and optical quantum information processing. He has published more than 200 scientific articles with more than 35 papers appearing in Physical Review Letters, Science and the Nature suite journals. His research expertise is in the field of quantum optics and metrology.