IQC-led research team achieves quantum optics breakthrough

Thursday, July 29, 2010

IQC researcher Thomas Jennewein in the lab
A significant breakthrough spearheaded by Institute for Quantum Computing (IQC) and the University of Waterloo's department of Physics and Astronomy is featured in the latest issue of the journal Nature.

The international research team achieved a longstanding milestone in quantum optics research — the direct generation of photon triplets.  This result has been sought for years but never achieved until now.

The breakthrough was made by IQC researchers Thomas Jennewein and Kevin Resch, Hannes Hübel and Deny Hamel, along with Alessandro Fedrizzi of the University of Queensland and Sven Ramelow of the Austrian Academy of Sciences.

“This is going to open a new frontier of quantum optics and allow a new class of experiments in quantum computing using photons,” said lead investigator Jennewein, an IQC faculty member and professor in the University of Waterloo's Physics and Astronomy department.

In the past, the generation of pairs of photons (particles of light) revolutionized quantum optics and made possible emerging technologies such as quantum cryptography and quantum computing with photons.

Typically, these photon pairs were created from strong lasers sent through a crystal — a process known as “parametric down-conversion.”

In their recent experiment, researchers created photon triplets by producing a first pair of photons using an optical crystal, then splitting one of the photon pairs further into two additional photons inside a second crystal.

It’s a process that was first conceived 20 years ago, but had never before been experimentally observed.

Because each triplet originates from a single pump photon, the quantum correlations will extend over all three photons in a manner not achievable when using independently created photon pairs.

It is expected that this photon-triplet source will allow tests of novel quantum correlations, and will greatly advance photonic quantum computing.

Jennewein praised his collaborators and research facilities at for the fruitful results: “It shows the value of a very strong team and a great environment for allowing breakthroughs to happen.”

In their publication, titled Direct Generation of Photon Triplets Using Cascaded Photon-Pair Sources, the researchers explain that these tripartite quantum correlations will significantly advance quantum information research.

The project involved collaboration between IQC’s Quantum Photonics Laboratory and Quantum Optics and Quantum Information group.

The research was supported by the Canadian Institute for Advanced Research, the Ontario Centres of Excellence, the Ontario Ministry of Research and Innovation, the Natural Sciences and Engineering Council of Canada, and the Canadian Foundation for Innovation.

Read the entire article at Nature online.


Founded in 2002, the mission of the Institute for Quantum Computing (IQC) is to aggressively explore and advance the application of quantum mechanical systems to a vast array of relevant information processing techniques.

A part of the University of Waterloo, Waterloo, Ont., Canada, IQC creates a truly unique environment fostering cutting-edge research and collaboration between researchers in the areas of computer, engineering, mathematical and physical sciences.

At the time of this release, IQC has 17 faculty members, 22 postdoctoral fellows and over 55 students and research assistants, as well as a support staff of 18.

The Institute for Quantum Computing acknowledges the support of the Government of Canada through Industry Canada and the Government of Ontario through the Ministry of Research and Innovation.