US Patent 7239439 Communication system using variable pattern acousto-optic modulation

A communication system uses a beam of light; a beam expanding lens; a lens for collimating the expanded beam into a column of collimated light; a plurality of acoustic transducers to project acoustic emanations perpendicularly to the column of collimated light, wherein each of the acoustic transducers is placed with respect to the column of collimated light to affect a different region of the column; a lens for collecting the collimated light from the collimating lens and light as affected by the acoustic emanation, wherein the collimating lens focuses the collected collimated light at a focal region; an optical filter at the focal region to separate the light as affected by the transducers from light not so affected; and a detector for detecting the light affected by the acoustic emanations.