Microvision's current pico projection engine uses red and blue laser diodes and a frequency-doubled "synthetic" green laser to create a full color image.
This ingenious technique which won its inventors, one of whom was Steven Chu, now America's energy secretary, a Nobel prize works by bombarding an object with laser light at a frequency just below that which it would readily absorb and re-emit if it were stationary.
By tuning the laser very precisely to the frequency of one particular sort of bond (such as that with a heavy carbon atom at one end), a molecule containing that bond can be shaken up.
And, just as light waves of the same frequency can be made to resonate in step with one another and so form a laser beam, it should be possible to make atoms of the same element resonate similarly.