The Jargon File (version 4.4.7, 29 Dec 2003):

software laser
 n.

    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 involving bounce message
    s can produce closely analogous 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.


The Free On-line Dictionary of Computing (30 December 2018):

software laser

   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 involving bounce
   messages can produce closely analogous results, with a
   cascade of messages escaping to flood nearby systems.  By
   mid-1993 there had been at least two publicised incidents of
   this kind.

   [Jargon File]