This is a fascinating example of crossover techniques in technology:
At over 600°C, a jet engine’s exhaust stands out like a beacon when seen in infrared, making it an obvious target for heat-seeking missiles – but a US Navy device might be able to thwart such missiles with ghost images projected in mid-air.
The traditional method of defence has been to eject hot flares to draw missiles away from the aircraft. This new approach would use lasers rather than pyrotechnics.
When focused to a point, a laser can produce a spot or filament of ionised gas in the air, known as a laser-induced plasma (LIP). The US military has long shown interest in LIP to create artificial lightning to defuse bombs or produce “non-lethal” effects.
Now, Alexandru Hening at the Naval Information Warfare Center Pacific in California is using lasers to create an array of plasma columns in the air. These are rastered like the beam in an old cathode-ray screen to create two or three-dimensional images in mid-air of ghost aircraft that can distract incoming missiles. [NewScientist]
It’s a fascinating idea for confusing thermal detectors, and transfers an old, obsolete technique for display technology using a phosphorescent material with … air. And, for those wondering about my forklift remark, the old cathode ray TVs seemed to get exponentially heavier as the screen size increased; the big ones, I should imagine, could require several husky men to deliver them to their customers.
