[Steely Tom]

There was a Heinlein story (Podkayne of Mars, maybe) in which one of the characters gets into a taxicab and, as soon as he has told the cavbby his destination and the cab has started moving, the image of a pretty girl appears in thin air and proceeds to sit down on his lap and start pitching him some product. He has to tip the driver to make the image go away.

Sounds like this guy is either using some sort of suspended particulate, or he is ionizing the air in some way. Just a guess.

(steely)

[longtermmemmory]

fyi, heilein's works are available in ebook format for your pda.

[maxwell]

some sort of suspended particulate, or he is ionizing the air in some way

Yeah that was my first thought:

modifies air particles to accept and reflect the image

"Accept": receives electromagnetic waves. "Reflect": beams 'em out again. So beams are absorbed and emitted back out again. Which means that specific energy levels are being pumped and released. Ionization could prep those energy levels...

Because take any ol' random particle: you bounce light off it, you have no idea of knowing what reflection angle that light is gonna take. Though maybe that's part of the "modification"... Hmmm..