Down in the laboratories of Macquarie University’s Diamond Laser Group, a team of scientists has worked out how to combine the power of multiple laser beams and focus them into one high-intensity beam that could potentially be directed at a military target, such as a bomb-carrying drone.
It’s an achievement worthy of Darth Vader.
“We described the concept as something reminiscent of the Death Star, in that we bring multiple laser beams together in a crystal, then have one single high-power beam coming out the other side,” says Professor Richard Mildren.
“In one experiment, we’ve been able to sum the power of multiple kilowatt-class laser beams to a single output beam up to eight kilowatts.”
Describing the Death-Star-like invention in a March 2017 paper for the Journal of Laser & Photonics Reviews attracted plenty of attention, Mildren says. “We're not making an actual Death Star, obviously!” he said.
Revolutionary weapons
Mildren, who is Deputy Director of Macquarie University’s Photonics Research Centre, is revolutionising the development of high-powered laser technology.
The group’s research – which won the most recent Eureka Award for its transformative potential in defence – has been supported by Australia’s Defence Science and Technology Group for the past five years.
They have perfected the use of an ultra-pure synthetic diamond crystal that allows the laser to tolerate very high power inputs.
Lasers are made by focusing energy into a crystal, which then amplifies a light beam between two mirrors, resulting in a beam that is very collimated, meaning that it is concentrated rather than dispersed.
“Diamond is a new, potentially disruptive laser technology because its thermal properties are so much better than any other optical material, by orders of magnitude,” Mildren says.
Diamond lasers can also pose less threat to eyesight than traditional lasers because they offer a wider choice of wavelengths, including those that have much higher safety factors.
New threats, new tech
Mildren says that lasers could potentially be very useful for defending against new, low-end military threats.
“With drones very cheap and easily made, defence agencies worry that adversaries could put threats including explosives on a very cheap drone, such as a quadcopter, so they're looking for new technologies to combat that,” he says.
“Defence agencies believe that high-powered lasers could provide a solution to protect infrastructure, assets and people from these low-cost weapons.”
High-powered lasers could also be used in space applications such as powering space vehicles and even tackling the growing space junk problem that threatens satellites.
The patented development of new laser technologies has attracted research investment from multiple defence agencies, and the technology has also been licensed in non-defence applications in quantum science and biomedicine.
Mildren says that there’s still a way to go before they are at the stage where high-powered lasers can be used in modern defence work.
But, while the Star Wars movies have provided laser researchers with useful analogies to help explain a complex model, Mildren says they fall short in other areas.
“Light sabres are a challenge too far. I know that’s going to be very disappointing,” he says.
“Getting a light beam to stop a metre from your hand is one issue – but the main problem is that light goes through light - you can't cross swords with laser beams.”
