Reinventing the laser

Macquarie University, Media releases

High-power diamond lasers, invented at Macquarie University, Eureka finalist

High-power lasers have many potential applications: from medical imaging to manufacturing, shooting down drones or space junk, or powering deep space probes. But current laser technologies overheat at high power.

Rich Mildren and his team have developed a technique to make diamond lasers that, in theory, have extraordinary power range. Five years ago, their lasers were just a few watts in power. Now they’ve reached 400 watts, close to the limit for comparable conventional lasers.

Their calculations suggest that their diamond laser technology could handle over a thousand times the current power. They’ve also shown that they can use diamond to focus multiple laser beams into a single beam. And they can create almost any frequency of light.

Diamond is an outstanding optical material and exceptionally good at dissipating heat. But it’s not very good at generating a laser beam as its dense structure makes it difficult to introduce the impurity additives normally needed to amplify light. Until now.

Rich discovered that he could use light scattering (the Raman effect). When light shines on the diamond crystals, some of it is scattered at a single frequency. His team has developed a suite of techniques to enhance this effect in diamonds to create their high-power lasers.

The first applications of Rich’s work are on their way. UK company M Squared Lasers has licenced the technology to create lasers for quantum computing and biological imaging.

US and Australian defence researchers are major investors in the research, which has the potential to be used to tackle drones, boat swarms, and missiles.

And the sky isn’t the limit. Rich says, “diamond provides us with a new approach to making lasers that could impact many areas of science and technology – we are looking to see how diamond’s unique properties can tackle big challenges such as high-power lasers for gravitational wave sensing or for manipulating space debris and small space vehicles.

“What’s exciting about Rich and his team is that they’re doing the basic research, they’re generating patents (seven to date), and they’re working with industry,” says Barbara Messerle, the Executive Dean of Science and Engineering at Macquarie University.

“Rich builds on a forty-year history of laser research at Macquarie University, started by Jim Piper,” Barbara says.

“We are now the world leaders in the development of Raman lasers, using the scattering effects of light within crystals to transform conventional laser output—to reach new wavelengths, higher powers, or improved quality.

“We’ve developed the science over the last decade from fundamental research through to device research and commercialisation to the point that it is an attractive and versatile commercial technology.”

Rich Mildren is a 2017 Eureka Prize finalist for the Australian Museum Defence Science and Technology Eureka Prize for Outstanding Science in Safeguarding Australia. The winner will be announced on Wednesday 30 August at the Sydney Town Hall.

Rich is Associate Professor in the Department of Physics and Astronomy, a member of the Macquarie University Photonics Research Centre, and a past Australian Research Council Future Fellow.

Watch Rich’s Eureka Prize video here

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