PHASR
Developed by the U.S. Department of Defense, the Personnel Halting and Stimulation Response Rifle (PHASR) is a non-lethal weapon designed to disorient and stun enemies rather than kill them. A light-based gun, the PHASR has been designed for use by both soldiers and U.S. law enforcement officials (police). The gun temporarily blinds enemies with focused laser beams. The laser lights, which operate at alternating wavelengths, serve to disorient people who look at them, rendering them unable to stand let alone fight. The good news is that the laser light used in this weapon does not inflict any permanent damage to people’s eyesight.
That "grenade launcher" in the pic is a Glock 17C pistol in caliber 9mm.