An optical laser works by bouncing
photons back and forth between two mirrors, one totally reflective
and one partially reflective. If the lasing material (usually a
crystal) has the right properties, photons scattering off the atoms
in the crystal will excite cascades of more photons, all in
lockstep. Eventually the beam will escape through the
partially-reflective mirror. One kind of sorcerer's apprentice mode inv
results, with a cascade of messages escaping to flood nearby
systems. By mid-1993 there had been at least two publicized
incidents of this kind.