Precision measurement is critical for timing, communication, electromagnetic and radio signals and underpins all measurement technologies. However, all electronics generate interference or ‘noise’, which prevents reading a pure signal.
Precision measurement is all about reducing the ‘noise’ in the system by:
improving the signal to noise ratio, or by
increasing the signal sensitivity.
Professor Michael Tobar is an internationally recognised scientist in precision and quantum limited measurement and testing fundamental physics. He leads the Quantum Technologies and Dark Matter Laboratory (QDM) at the ARC Centre of Excellence for Engineered Quantum Systems (EQuS) and the ARC Centre of Excellence for Dark Matter Particle Physics (CDM), at The University of Western Australia (UWA). The QDM Lab is considered a world leader in precision measurement, low temperature physics, hybrid quantum systems and testing fundamental physics.
Over the past two decades, Professor Tobar and his team, including long-time colleague Professor Eugene Ivanov have invented clever ways to build devices that respond to signals much more sensitively. Their patented technologies have been commercialised and purchased globally for multiple applications from fundamental research, metrology, high-tech communications, radar and defence.
That’s been the philosophy of my career – to develop my passion for fundamental physics; but as well develop technology and commercialise it where possible.
Prof. Michael Tobar, UWA
A bar above the rest
In the early 1990’s, a decade before the new discipline of quantum technologies even existed; a team led by UWA Emeritus Professor David Blair had already begun their ground-breaking research.
PhD student, Michael Tobar and Research Associate Eugene Ivanov were working on the detection of gravitational waves. They used precision microwave frequencies of an interferometer to produce mechanical oscillations that would occur if a gravitational wave hit a resonant bar. From this they developed very low-phase noise oscillators and highly sensitive transducers – optomechancial precision technologies that use photons to cool the noise and read out very tiny displacements. In 1996, the team also undertook the first ever resolved sideband cooling of a mechanical oscillator.
Their technology lay the foundations of further research in gravitational wave detection as well as other quantum technologies that are now gaining potential worldwide.
The technology is very interesting because it can be used in fundamental physics and for translational outcomes.
Prof. Michael Tobar, UWA
It’s sapphire crystal clear
The Sapphire Clock invented by Emeritus Professor David Blair in 1984 underpinned the research and invention of the Cryogenic Sapphire Oscillator by Professors Tobar and Ivanov. As sapphires produce a very low noise level, they can define frequency better than other types of crystals and resonances. Their ultra-high-performance technology had very low loss, well-defined frequency, and became the world’s first lowest-noise oscillator.
Several patents were granted between 1998 and 2011 with the help of Thomas Schnepple, Senior Commercialisation Officer at the UWA Research Development and Innovation Office.
In 1995, Professor Tobar approached Jesse Searls from Poseidon Scientific Instruments (PSI) who were interested in making the best radars for the communications and defence industries. Both PSI and the Australian Research Council (ARC) became large supporters of the research, with eight collaborative research grants between 1996 and 2011.
The technical leadership of their work has withstood the test of time…for 20 years no other company on the planet has been able to produce oscillators which approach the performance that comes close to the oscillators based on the collaborative efforts of Mike, Eugene and PSl staff.
Jesse Searls, Ex Managing Director, PSI Pty Ltd
PSI licensed and commercialised the technology in 1995 for use in their product range. Sapphire Crystal Oscillators was also being supplied globally for use in multiple applications in: metrology, defence, high-tech communications and to perform some of the most precise tests of theoretical physics.
French Space Agency, for the Atomic Clock Ensemble in Space Mission
Paris Observatory for their time network
National Measurement Institute, Sydney Australia
Humboldt University, a test of the theory of the speed of light, which still holds as the current best test
to countries in Asia for use in precision timing systems
In 2012, Raytheon, a global defence capabilities company, and one of PSI’s biggest customers acquired PSI. The technology complemented Raytheon’s suite of world-leading technology and became an essential component in their low noise defence radar.
A microwave interferometer oscillator
Sapphire Cryogenic Oscillators need to operate at extremely low temperatures, restricting their practical application. Further fundamental research in microwave circuits led the team to discover how to bring the noise level down further, in a non-cryogenic environment
They discovered that ‘exciting’ the system with photons could help make the noise very low.
They used an interferomic way of trapping microwave signals in crystal rather than in metal, thus reducing the extra noise from electronics that would otherwise wash out a signal. Their microwave interferometer works at room temperature, is ultra-stable and improves the noise in the system by 1000-10000 times, with 10 patents between 1992 to 2012. They still use this technology in high precision sensing and oscillators, with their latest sensor technology patented in 2019.
t’s so interesting to build these precision technologies. It opens up many possibilities to improve precision of current measurements in many applications.
Prof. Michael Tobar, UWA
Taipan gravity gradiometer
Gravity gradiometers are used to measure Earth’s gravity gradients and changes in subsurface geology. They are a large manned machines commonly used in the mining, defence and exploration industries.
In 2016 Lockheed Martin, the only company world-wide that provides commercial gravity gradiometers, approached the QDM Lab with financial backing and a view of developing a more portable version.
In collaboration with Trinity Research Lab, the QDM Lab team invented a miniaturised ribbon gravity gradiometer, nicknamed the Taipan Sensor. The technology is based on the same precision principle as the resonant bar, though instead of gravitational waves, the non-cryogenic device looks for distortions in gravity gradients.
It is the smallest gravity gradiometer ever built, with enormous translational outcomes. It is portable, unmanned and can be deployed via drones to scan the surface of an area, in drilled bore holes to look for minerals and can travel in submersible vehicles. Taipan Sensors can be used more broadly in existing industries and as well in new markets such as space exploration.
The team patented their novel technology in 2020. Lockheed Martin license the technology and continue to develop it for use on drones. Successful as a prototype, the sensor is currently in testing phase. For Professor Tobar the technology opens up even more possibilities in fundamental physics.
My main focus is using these technologies to do better detection of dark matter. To find out what quantum gravity is. To do precision measurements which might look for small changes in physics that we don’t expect.
Prof. Michael Tobar, UWA
A very dark matter
Dark matter makes up 80% of the universe, yet we still don’t understand it. Since 2010, Professor Tobar has been using precision measurements to search for dark matter and dark sector particles.
The QDM Lab is equipped with three milli-Kelvin (dilution) refrigerators that the team use to perform state of the art experiments. The refrigerators can cool temperatures to a point so low, the fundamental limits of noise and thermal vibrations are eliminated and what is left are quantum fluctuations.
The systems are capable of turning dark matter into photons. Once dark matter is converted, the team use their technology to try to read the signals. The team are now working on new ways to maximise the signal. The newly formed ARC Centre of Excellence in Dark Matter Particle Physics has been funded by the ARC to develop the ultra-precise measurements of frequency and other quantities that are needed for sub-eV particle dark matter searches.
The team’s research has wide-ranging implications for how dark matter can be applied in the future. From developing even better low noise oscillators, more secure communication capabilities and even generating electricity.
If we develop this, then we have a way of detecting dark matter using these low noise oscillators. My next thought will be generating electricity from dark matter.
Prof. Michael Tobar, UWA
Detecting a force from nothing
In 2017, a collaboration between Dr Jacob Pate from The University of California Merced and Professor Tobar provided a new way to measure tiny forces, and use them to control objects.
The Casimir effect is the force created by bringing two objects close together. The team unexpectedly discovered that the force is not only affected by quantum noise. When the temperature is high enough, thermal noise can also have an effect.
Touching objects can ruin them and destroy their properties. Their find has enormous implications for future work as objects can now be manipulated without touch.
We saw this force manipulate the object we were measuring. Now we can manipulate an object without touching it.
Prof Michael Tobar, UWA
5G
Commencing in 2021, the team have also begun development of a more high-frequency device that is tuneable to the 5G network. Unlike 3G and 4G, in 5G bands, the properties of the oscillator and its base noise is one of the most important parts of the system. Their work in this area has gained wide interest with invitations for Professor Tobar to speak at international and national symposiums and workshops on low-phase techniques.
Inspiring the future
Professor Tobar has been recognised for his work in precision measurement and fundamental research testing by numerous international and national awards. He and his team’s discoveries and inventions have also gained notable recognition globally.
In 2014, Professors Eugene Ivanov and Michael Tobar received a prestigious Clunies Ross Award from The Australian Academy of Technological Sciences and Engineering in recognition of their microwave circuit and sapphire dielectric resonator technology.
However, for Professor Tobar his most important goal is to share his passion with the next generation of scientists and to inspire them to reach their full potential through participation in ground-breaking research.
It’s fun, challenging and extremely interesting. One of my main goals is to mentor young scientists. I really enjoy working with young, clever scientists.
Prof. Michael Tobar, UWA
And when new researchers join the QDM Lab, they are greeted with this motto, which the team firmly stand by:
We’re always proving how stupid we are. Because when you come up with something new, then you understand it, which makes you realise how stupid you were before you understood it!
QDM Lab motto
We thank the University of Western Australia for contributing this information. We acknowledge that the content has not been altered from the original intent of the author.