A person with a casual interest in optical science could be excused for believing that it is a modern field of study, originating in the 20th Century. Although the invention of the laser and optical fibres dates only from the 1960s, the history of optical science actually stretches back for thousands of years.
Most recently this rich history was explored in the International Year of Light in 2015, a celebration of both the history of optical and photonic research and the bright future offered by this important discipline.
The truly revolutionary inventions of the laser and optical fibres in the 20th century were a major advance in the field, continuously transforming our communication systems and the ways in which modern humans can interact as a species.
Our 21st Century is poised to be an era of which will be defined by photonics and nanotechnology. It may seem that the global internet enabled by these technologies is already revolutionary enough, but we are only just at the beginning of the transformative opportunities offered by this technology.
Australia is well positioned to play a leading role in this future, both in terms of our capacity for fundamental discoveries and translation into new real world technologies such as photonic sensing.
We know that photonics is the linchpin of a multi-trillion-dollar industry and itself a 500-billion-dollar global industry and an essential part of the Australian research ecosystem.
As well as underpinning the telecommunications infrastructure, photonics technologies are playing critical roles in other areas – health and medicine, defence and security, infrastructure and transport and energy and the environment.
In these areas, photonic sensors are enabling new smart technologies that can sense and monitor the health of people, infrastructure and the environment.
Photonics sensing has been around for a long time. There are numerous examples of highly successful photonic sensors that have been deployed extensively – fibre optics that run along railway lines to measure strain and inform maintenance planning; sensors that are deployed in the mining industry to detect toxins; and current sensors that are used widely in the power industry.
Australia has a long history of leading-edge research and innovation in photonics sensors with numerous world leading groups and centres across Australia.
With the advent of nanotechnology and the establishment of major nanofabrication infrastructure in Australia, the research impetus is to establish new smart sensors that are small enough and low cost enough that they can be distributed everywhere and can address the grand challenges of the future.
The NSW Government, through the leadership of our Chief Scientist and Engineer, Professor Mary O’Kane AC FTSE, has invested in the NSW Smart Sensing Network (NSSN), a collaboration between the University of Sydney and the University of New South Wales which I co-direct with Professor Justin Gooding from the University of NSW.
The Network will harness the state’s significant scientific, information communication technology (ICT) and engineering capabilities across academia and industry to provide state-of-the-art solutions in chemical and physical sensing to help address major societal issues: from the environmental impacts of the resources industry, to security at airports and improving quality of life for our aging population.
We are currently in an establishment phase, which is emphasising five pilot projects to address key challenges in NSW. At the same time, we are developing a network of researchers, end-users and industry partners to be the basis of the next phase of development.
At the University of Sydney, we are focusing on air-quality monitors with an emphasis on developing photonic sensors to detect particulate matter and gases, particularly related to coal mining and the associated rail corridor in the Hunter Valley. The challenge is to develop low-cost and compact sensors to be the basis of a network of sensors that map the spatial and temporal spread of coal particles around the rail corridor in the Hunter Valley, to better inform residents, policy makers and regulators of air quality issues.
This exciting project is applying photonic sensors to a real-world issue that is not only of local concern, but also has global applicability. We expect to apply this methodology to a whole range of pollutants.
In the longer term, we will incorporate these photonic air-quality sensors on chips small enough to be part of a mobile platform, perhaps even a smart phone. This vision aligns well with the CUDOS research program which has spent the past decade developing a photonic chip based on silicon technology – the same technology platform that is the basis of the microelectronics platform in your phone.
CUDOS, the Australian Research Council Centre of Excellence for Ultrahigh bandwidth Devices for Optical Systems, represents a consortium of six Australian universities and partner organisations all around the world, headquartered at the University of Sydney.
We now have photonic circuits that are etched into silicon wafers providing the basis of highly advanced signal processing devices. We are fabricating these “chips” using lithography equipment already used in the semiconductor industry, meaning the techniques developed can be translated to mass production using that same equipment.
We are working with local companies such as Silanna, based in Sydney, whose silicon-on-sapphire technology is well-suited to photonic sensor applications. At the same time, CUDOS is commercialising many of its inventions through spin-off companies and partnerships with local companies.
The most recent addition to the Australian photonics research community is the University of Sydney’s Nanoscience Hub, part of the Australian Institute of Nanoscale Science and Technology (AINST). This new facility incorporates more than 800 square metres of state-of-the-art clean room space filled with the tools that are needed to fabricate and prototype these photonic chips.
Our long-term vision is to bring a complete laboratory onto the chip, incorporating light-based circuits (photonics) with acoustic functionalities for manipulating and actuating fluids on the microscale, in the silicon platform that allows a seamless interface with electronic components.
We are already building photonic spectroscopy techniques into the same silicon chip that performs electronic processing in your smartphone. This will enable your smartphone to perform tasks such as medical diagnosis, including analysing blood or saliva, or sense pollutants in the environment via spectroscopic analysis.
The ability to manipulate fluids will be the basis of a biological laboratory that is part of the photonic chip. Our approach is to use acoustic waves (sound) that can be generated on the chip. These are not the traditional sound waves that we hear or use in ultrasound, but ultrahigh frequency sound waves.
We refer to them as “phonons”, which are particles of sound, just as photons are particles of light. We are talking about hypersound – phonons with frequencies from 100 megahertz to tens of gigahertz. Harnessing hypersound on a chip enables the manipulation of microscale biological and chemical elements, meaning we can mix, sort and select and even create a centrifuge on a chip.
This laboratory-on-a-chip will literally be small enough to be part of your smart phone and built into the same silicon chip already performing digital operations, and with cloud connectivity it will allow wide-scale environmental sensing with local accuracy.
Eventually we anticipate this technology will allow your smart phone to be transformed into a sensor that will sense your local environment and personal health.
Think of it like a Twitter feed on your smart-phone, except all of the information is about you, your body, your health and your immediate environment – as much or as little information as you need instantaneously available.
This will allow people to make informed decisions about their health or the environment they choose to live in.
We really are sensing our way to a very bright future.
This editorial has been reprinted courtesy of ATSE Focus magazine.
Professor Benjamin Eggleton FAA FTSE is an ARC Laureate Fellow and Professor of Physics at the University of Sydney and is Director of the ARC Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS) and co-Director of the NSW Smart Sensing Network (NSSN). He worked in the US for Bell Laboratories/Lucent Technologies before joining the university. He won the 2011 Walter Boas Medal, the 2011 Eureka Prize for Leadership in Science, the 2007 Pawsey Medal, and the 2004 Malcolm McIntosh Prize for Physical Scientist of the Year. He is a former president of the Australian Optical Society (AOS).
Written by : Ben Eggleton