I came across this 1964 archive photo on the Associated Press showing a demo of a "Laser Rifle" that promised to be a weapon of the near future for the Army. Notice the not-so-small power supply the soldier would need carry to power the laser. I guess they are still working out the bugs on this one.

Harold Blodgett, Laser project officer of the Army Material Command, Washington, D.C., demonstrates the use of the laser, a word coined from the first letters of Light Amplification by Stimulated Emission of Radiation. The power pack for the instrument is at lower left. Blodgett staged the demonstration at a press conference at the Frankford Arsenal in Philadelphia, March 6, 1964. Eventually the laser source will have applications of importance to the Army, possibly as a weapon.

(AP Photo/John F. Urwiller)