The night sky could soon be lit up with gigantic three-dimensional adverts, thanks to a Japanese laser display that creates glowing images in thin air.
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The display utilises an ionisation effect which occurs when a beam of laser light is focused to a point in air. The laser beam itself is invisible to the human eye but, if the intensity of the laser pulse exceeds a threshold, the air breaks down into glowing plasma that emits visible light.
Two off-the-cuff predictions: A massive increase in spurious UFO sightings and a decrease in backyard astronomy due to light pollution.