Now, unjammable quantum radar that could make stealth tech obsolete
Researchers in the US have employed the quantum properties of photons to create an unjammable radar signal.
Conventional radar is vulnerable to a range of technologies, ranging from dropping chaff to create false reflections, to drowning the radar frequency with noise.
More sophisticated radar can deal with such ploys, but the most sophisticated radar jammers are able to intercept the signals and send back false information.
A team from the University of Rochester, New York, has now shown how the quantum properties of photons can be used to outsmart this advanced stealth technology, the Daily Mail reported.
The new radar concept relies on the fact that any attempt to measure a photon always destroys its quantum properties, MIT's Technology Review explains.
To exploit this curious property, the Rochester team suggest using polarised photons to detect and image objects.
If a stealth aircraft attempts to intercept these photons and resend them in a way that disguises its position, it would inevitably change the photons' quantum properties - revealing any interference.
"In order to jam our imaging system, the object must disturb the delicate quantum state of the imaging photons, thus introducing statistical errors that reveal its activity," the researchers said.
The technology works in a similar way to quantum key distribution for cryptography, where any eavesdropper would change the quantum properties of the key by listening in, revealing his or her presence.
Mehul Malik, who led the team that carried out the research at Rochester's Institute of Optics, tested the concept by bouncing photons off a stealth bomber-shaped target and measuring the return signal's polarisation error rate.
The system easily imaged the war plane without any eavesdropping, but when the adversary intercepted the signal and modified it to send back the image of a bird, the radar was easily able to see through the ruse.
The research is published in the journal Applied Physics Letters.