Do you chuck out reams of printed paper after it has outlived its purpose? Instead of continuously buying new paper, what if you could simply erase what's printed on it and use it over? That's the idea behind this laser eraser that literally vaporizes the toner to make a sheet of paper blank again.
Developed by scientists at Cambridge University in England, the trick was to determine exactly what frequency and duration of light would zap the toner ink, without damaging the underlying paper substrate. It turned out that green laser light at 532 nanometers with a pulse of 4 nanoseconds did the trick, zapping all colors of toner while leaving behind a perfect white sheet of paper.
While the researchers didn't give specifics, it seems likely that this technology could be incorporated into a laser printer or photocopier, giving you an erase mode to undo things when you make a mistake.
That could be useful if your boss starts walking towards the copier room, just as you were making copies of your head.