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Canadian laser expert claims major U.K. science prize

Dr. Paul Corkum, front, at the University of Ottawa labs that are part of the Joint Attosecond Science Laboratory.

University of Ottawa

It's been a good week for one of Canada's top federal scientists.

On Tuesday, Paul Corkum, a laser physicist who divides his time between the National Research Council and the University of Ottawa, learned that he has been awarded the Royal Medal, an honour bestowed annually by the U.K.'s Royal Society.

Only a handful of Canadians have won the medal, with a list of illustrious recipients that includes the likes of Michael Faraday, Charles Darwin and Lord Kelvin. The medal, which dates back to 1826, recognizes "the most important contributions to the advancement of natural knowledge" by scientists in Britain and Commonwealth nations, the society's description notes.

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"It's amazing to be in this long line of people who stretch back over almost two centuries," said Dr. Corkum, speaking this week from a meeting with U.S. colleagues in Washington. "It's a very high honour."

At 73, Dr. Corkum can hardly be accused of resting on his laurels. His latest work, published Thursday in the journal Science, describes a set of novel laser experiments conducted at the NRC's facility on Sussex Drive in Ottawa that could open the door to a new form of quantum technology.

"We don't yet know how important this will be," Dr. Corkum said. But he added that the work has led to a patent for its potential to measure miniscule changes in voltage at small scales, such as on a computer chip.

Dr. Corkum is best known for his development of attosecond lasers, powerful sources of light whose pulses are measured in quintillionths of a second – fast enough, for example, to probe the behaviour of individual electrons within the chemical bonds that hold together much of our material world.

More recently, his team has been blasting silicon chips with lasers to study the generation of so-called high harmonics – colours of light that are emitted at much higher frequencies than the light that went in.

Dr. Corkum compared the effect to bashing out a low note on the piano, which in turn causes notes at higher octaves to resonate on their own. In more technical terms, the effect is a quantum process that is triggered when the electrons in a material are yanked by passing laser light, causing them to violently recollide with the atoms they are part of.

The effect was originally observed in gasses, but it has more recently has been discovered to occur in solid materials.

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"This was a big surprise to everyone working the field," said Dr. Corkum, and potentially far more useful because "there are things you can do in solids that you can't do in gasses."

In the work published this week, Dr. Corkum and his team irradiated bits of silicon to generate high harmonics. In some cases, the silicon surface was "decorated" with tiny pyramid-like structures that helped to concentrate the emitted light. In other experiments, additional metals were added to the silicon to produce different effects.

During the experiments, the team found that the characteristic of the emitted light changed in the presence of an electric field. That meant the light could be used as a detector of a voltage in the solid, which means it could be used as a sensitive probe of voltages over very short distances "That's our hope," Dr. Corkum said. "There's a long way to go to develop the technology."

Another potential application includes using high harmonics as "a light source for viewing the fastest chemical and material processes," said David Reis, a Stanford University physicist who was not part of the study.

He added that Dr. Corkum's latest work was noteworthy because it showed, "that by tailoring the microscopic properties of the materials, one can manipulate both the generation and emission pattern" of the high harmonics, an area of tremendous interest among physicists who study the interaction of matter and light on short timescales.

In winning the Royal Medal, which comes with £10,000 (roughly $16,000 Canadian) in prize money, Dr. Corkum follows in the footsteps of Canadian researchers Gerhard Herzberg and John Polanyi, both of whom went on to win the Nobel Prize.

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A third Canadian medalist was Anthony Pawson, a celebrated University of Toronto biomedical researcher who some considered a likely candidate for the Nobel Prize before he died in 2013. In 2015, Dr. Corkum was identified by Thomson Reuters as a potential Nobel winner.

A presentation ceremony for the medal is being organized for later this fall, a spokesperson for the Royal Society said.

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