la·ser
(lāzər)
(lāzər)n.
1.
a. Any of several devices that emit highly amplified and coherent radiation of one or more discrete wavelengths. One of the most common lasers makes use of atoms in a metastable energy state, which, as they decay to a lower energy level, stimulate others to decay, resulting in a cascade of emitted radiation.
b. A beam of radiation emitted by a laser.
2. Sports A ball or puck sent in a straight line at high speed: shot a laser into the upper right corner of the goal.
[l(ight) a(mplification by) s(timulated) e(mission of) r(adiation).]
lasertop:lasers using argon, organic dye, and a crystal made of neodymuim and YAG as different media for exciting atoms
bottom:a ruby laser
laser