Picture this. You’re at a Gourmerican burger joint chomping a cheeseburger, when an outspoken vegan friend starts preaching that you’re killing the planet. Last week, that same vegan downed a pricey glass of pinot before their flight to a far-flung destination, armed with their strongest mossie repellant and first aid kit. Anything amiss?
Marketers have longed dreamed of being able to identify every one of their customers, regardless of how they are interacting.
It is a capability that digital technology has delivered in the online world, but as yet no method has proven effective for the vast majority of offline interactions. Facial and mobile device recognition have both yet to become sufficiently accurate to deliver a positive ID against a known identity in all situations.
But what if you could recognise a person by their own unique chemical signature?
It’s not a crazy as it sounds.
The emerging science of terahertz radiation spectroscopy is enabling researchers to perform a widening range of scanning and recognition activities. And possibly – at some point in the distant future – it might enable the identification of individuals.
Data61 researcher, Ken Smart, has been investigating the uses of terahertz radiation for 15 years as a scanning and detection technology.
“It has the ability to penetrate opaque materials, such as packaging and things like that,” Smart says. “You can look for voids inside of materials, or you can look for corrosion under paint. And it has a high sensitivity to liquids, so you can tell the water content of the thing you are looking at.”
All of that makes terahertz scanners particularly adept at instantly detecting substances like pesticide on fruit. Smart says this is of huge value to the agricultural sector, where some traditional chemical tests might take up to 24 hours to deliver a result – an appalling delay for anyone wanting to sell perishable goods.
“If you can determine how much is there within minutes, you have an advantage,” Smart says.
The technology could also be used to detect counterfeit food, such as when expensive fish are substituted with cheaper ones in restaurants. It has also been used to scan beneath works of art to determine what might have been painted over, by identifying the individual pigments.
The terahertz radiation band sits between the millimetre radiation band, often used for full body scanners at airports, and the optical radiation band used by human eyes. It is a non-ionising form of radiation, meaning it is safer than some other scanning techniques, such as those that use x-rays.
That terahertz radiation is only now being considered for commercial applications is due to recent breakthroughs which have made it easier to create devices with the power profile needed to work with it.
“It’s easier now to make high power devices, so you get stronger penetration and it is easier to see different things,” Smart says. “As you go up in frequency the wavelength gets smaller so your resolution increases, and you can see finer detail that you can’t capture at lower frequencies.
“You get to see an almost-unique signature. The more refined a substance is, the more unique its signature is. But once you start combining substances it gets a little murkier to tease out which one is which.”
Smart says the power profile of terahertz scanners also make standoff testing difficult, with an effective range of ten metres.
“So when it gets beyond that you have atmospheric effects and all sorts of things working against you,” Smart says. “But as people work their way around some of these problems there can be solutions found.”
And while it can scan through cloth and paper, it can’t penetrate metallic objects.
Despite the possibilities, however, the murkiness and range issue mean it may be some time before shop owners are identifying visitors by their unique chemical signature.
“That’s in the future, quite a long way,” Smart says.