@cinebox
Yes, good old Light Amplification by Stimulated Emission of Radiation.
Though the old Soviet laser pistol used a neodymium-doped yttrium aluminium garnet rod instead of one using ruby, That's because it pumped the rod with flash bulbs instead of a strobe.

http://www.projectrho.com/public_html/rocket/sidearmenergy.php#sovlasgun
#LaserPistol #AtomicRockets #RayGun