Laser pest control
Zzzzzzzz…. We’ve all been kept awake at night by a mosquito’s infuriating whine. But it could all be a thing of the past with the photonic fence, a high tech laser weapon set to wage war on blood-sucking bugs.
‘What the photonic fence does is optically identify insects, optically evaluate them and then optionally can shoot a high powered laser at them,’ explains 3ric Johanson, staff scientist at Intellectual Ventures , a company focused on fostering new inventions.
It sounds like overkill, but a radical solution like the photonic fence may be exactly what’s needed in the fight against malaria, a disease which kills an estimated 1 million people every year. Widespread in Africa, but also affecting parts of South America and Asia, malaria is caused by a parasite that's passed between humans and mosquitoes. Breaking this cycle of infection is key to eradicating the disease.
Declaring war on malaria
‘Mosquitoes are not born with malaria,’ says Johanson, ‘they get it from biting an infected human. So anytime you can break the link between the infection of humans and the attraction of mosquitoes, then you’ve reduced the impact of malaria in that region.’
Bednets, repellents and pesticides are used widely, yet malarial infection rates remain stubbornly high. Chemical pesticides or repellents also come with many undesirable side effects. ‘Frequently there’s a lot of casualties of war along the way,’ says Johanson. ‘They’re not selective and the chemicals may have ecological impacts elsewhere.’
The photonic fence software on the other hand can single out individual mosquitoes like a skilled sniper, avoiding harm to any innocent bystanders whether insect or human. ‘The photonic fence has very predictable environmental impacts because of how selective it is – this isn’t something that’s going to kill bumblebees or houseflies,’ adds Johanson.
The set-up consists of a camera accompanied by two types of laser, pointed at a retro-reflective backdrop. First of all, a very low powered laser is used to cast shadows of potential victims onto the backdrop. ‘This retro-reflective material is the same stuff they put on road signs - it sends light energy back in the same direction it came from,’ comments Johanson. ’Anything that walks between that very reflective surface and the camera leaves a very strong silhouette.’
This shadow, tracked by the camera, is analysed to gather clues about the bug’s identity, measuring speed, body size and wing beat frequency.
Mosquitoes beat their wings about 600 times per second, producing the characteristic high-pitched whine that makes for many a restless night. On the flipside, this makes them easy to identify. ‘Wing beat data is actually critical in delivering information about the insect species,’ explains Johanson. In fact, it even gives away the sex of the mosquito. And since only females of certain species of mosquito carry malaria, the rest can be spared.
Using all this information, we can tell with a fairly high level of accuracy what sort of insect it is we’re looking at,’ he adds. And once a mosquito has been identified, a high powered laser beam seals its fate.
‘We have a number of systems in place before we shoot the high powered laser to ensure we’re not shooting something that shouldn’t be harmed,’ says Johanson. The reflective backdrop also prevents the laser beam from travelling any further.
From Africa to your garden
Intellectual Ventures are attempting to make the contraption as cheap as possible, but are also studying how effective it is likely to be in malarial zones. ‘We spend a lot of time modelling how malaria spreads,’ comments Johanson.
The photonic fence could potentially be used to combat other insect-borne diseases in future, but it has attracted a lot of interest from people simply keen to free their homes of mosquitoes.
‘A lot of folks have been very interested in having these in their back yard. That’s not why we initially started this project, but as a side effect it appears that there’s a lot of commercial interest,’ says Johanson. ‘I think I’d quite like one in my back yard too!‘
This month is the 50th anniversary of the laser. Find out more at laserfest.org
Watch slow motion footage of an unlucky mosquito facing execution by laser:
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