Turbolasers are the weapon of choice for large starships throughout the Star Wars Saga.
“They’re so small they’re avoiding our turbolasers”
~ Imperial, A New Hope
These laser weapons help protect star destroyers and the like from attack. You see them throughout the various films as well as the animated series (Clone Wars, Rebels).
I’m very happy to say that turbolasers are no longer fictional. While they’ve been experimental for decades, the first U.S. battleship to deploy this technology occurred in 2014. The Navy Laser Weapon System (LaWS) was deployed and operated in the Persian Gulf on the Ponce U.S. Naval vessel in August of 2014. Here’s a demo video:
LaWS was developed for obvious reasons: it’s a freakin’ laser! But more specifically, it is being used as a defensive weapon against other ships, UAVs, etc. Humans aren’t to be targeted with the weapon (just not koshur in the international community).