Eureka finalist Rich Mildren working with his diamond laser. Credit:Chris Stacey Professor Mildren won one of 15 awards presented at the Australian Museum's Eureka Prizes, often called the "Oscars of Australian science", and also walks away with $10,000 in prize money. Before Professor Mildren got involved, laser research haD been stuck on a plateau. Lasers typically work by pumping energy into a crystal, often a garnet or sapphire. The crystal then releases that energy as light, and two mirrors are used to channel it into a focussed beam. "To make a laser which is powerful enough to knock out a missile needs a lot of power," says Professor Mildren. At least 100 kilowatts, he estimates.

To generate that much power, a huge amount of energy and heat need to be pumped into the crystals. So far, no one has been able to build a practical laser that gets above about 15kW before the crystal starts to melt or lose performance. This image shows several lasers hitting a diamond, which concentrates them into a more powerful beam. Image supplied by Macquarie University. Professor Mildren's award-winning breakthrough is to coax a man-made diamond into generating a laser. "It's an extreme material, the hardest on the planet, but it's also the most thermally-conductive material on the planet. It's a material that can go up to very high laser beam powers," Dr Mildren says.

So far, Professor Mildren's team have slowly been ramping up the power – they hope to break 10kW in the next few years. But the team's modelling shows a diamond should easily be able to handle the extreme heat generated at 100kW-power levels, and could even push close to a megawatt. "The ability for it to generate very high power laser beams is something Defence is going to cotton on to very quickly," says Professor Mildren. But it's not just inventions with potentially destructive powers that have taken out the prizes. Professors Elena Ivanova and Saulius Juodkazis Another winner, Professor Elena Ivanova​ found her eureka moment – for which she was jointly awarded the University of NSW Eureka Prize for Scientific Research – in the flutter of a dragonfly's wings.

She and fellow winner Professor Saulius Juodkazis​, both working at Swinburne University, had been studying the wings' remarkable antibacterial properties. They seemed entirely impervious to any kind of bacterial infection. When she looked at the wings under a microscope, Professor Ivanova expected to spot some kind of waterproof coating that caused the bacteria to slide off. Instead, she found an extraordinarily-complex nano-scale pattern carved on the wings. When a bacterial cell tried to land on the pattern's bumps and ridges, "they were chopped!", says Professor Ivanova. "It was like, eureka!"

This is a simulated image of a bacteria cell hitting the nanomaterial and being ruptured. She likens the process to squeezing a balloon with your fingers. The nano-pattern squeezes the bacteria's cell wall, stretching and eventually tearing it. Her team is now working on replicating the dragonfly pattern on titanium, where it has promise as a strong natural antibiotic. She hopes to incorporate it into hip and knee replacements, and eventually cover hospital walls and floors with the pattern to stop the spread of infection.