A team of physicists at The University of Western Australia has invented a new type of amplifier which is powered by light rather than electricity and could be used on spacecraft to help locate magnetic asteroids.
The research team, led by Professor David Blair, invented the device while trying to solve a technical problem in kilometre scale gravitational wave observatories that aim to detect black holes across the universe. The results are published today in the prestigious international journal Physical Review Letters and will be simultaneously presented at Columbia University in New York as part of a world conference on gravitational waves.
"We have turned a problem for gravitational wave detectors into a new gadget with an amazing range of applications," Professor Blair said.
Professor Blair's team includes research director Dr Chunnong Zhao, research fellow Dr Li Ju, and International Postgraduate Research Scholarship students Haixing Miao, Slawomir Gras and Yaohui Fan as well as students Viet Dang, Lucienne Merrill and Zhongyang Zhang who are testing two different versions of the amplifier.
"We all use amplifiers everyday - they are all around us, in radios, televisions, phones and MP3 players," Professor Blair said. "They use electricity to increase the volume of sounds or the strength of radio signals. Every form of telecommunication and almost every sensor used for monitoring everything from aero-engines to human bodies depends on an amplifier. Even light can be amplified and this is necessary for the operation of optical fibre networks."
Professor Blair said the new device could directly amplify sound, turn sound into light and suck energy out of objects in a process called optical cooling.
"We predict that it can cool vibrations until the only vibration that remain are ghostly quantum fluctuations," he said. "In a slight variation the same device can amplify radio waves and turn these into light, or measure tiny magnetic fields down to a millionth of the strength of the earth's magnetic field.
"The new amplifier operates by shining laser light onto a flexible mirror. When the light reflects off the mirror, the mirror recoils and the tiny recoil is enough to convert the light into a new light beam of a slightly different colour, and in a pattern that allows it to build up by resonance as it reflects back and forth between the flexible mirror and a second mirror. This build up of the light is actually powered by the incoming laser beam."
The team calls the new device an opto-acoustic parametric amplifier or OAPA. The OAPA combines two patterns of light waves with a sound vibration. Earlier devices developed in Europe and the US used a single light pattern. These devices could also amplify, but they suffered from noise effects that gave them limited performance.
"Our breakthrough was to work out how to combine two separate light wave patterns with the pattern of vibrations in a flexible mirror," Professor Blair said.
Now the team plans to demonstrate optical cooling with the device, and to make a sensor for airborne detection of magnetic minerals in conjunction with research and development company Gravitec. Some team members also hope to make a device to be put on spacecraft to help locate magnetic asteroids that could be mined and used in future space exploration.
The project is a result of an international team effort, with scientists from Australia, China, Poland, Chile and US all contributing to the invention, which was funded by the Australian Research Council and WA Government Centre of Excellence.
Professor David Blair (UWA School of Physics) (+61 4) 09 687 703
or SKYPE: d_blair
Viet Dang (UWA School of Physics) (+61 4) 21 189 815
Dr Alex Veryaskin (UWA School of Physics) (+61 8) 6488 1768 / (+61 4) 00 922 329
Janine MacDonald (UWA Public Affairs) (+61 8) 6488 5563 / (+61 4) 32 637 716