Pulse laser turret

The Pulse Laser Turret is a Covenant starship weapon that can fire on both space and ground targets. These turreted beam weapons are known to have been mounted on Covenant Destroyers, Covenant Heavy Cruisers, and Covenant Carriers. Strangely enough, UNSC Prowlers also have these energy weapons: highly unusual, as United Nations Space Command starships typically utilize projectile or explosive weaponry. However, it makes sense that since ONI is the group responsible for reverse-engineering Covenant technology that their ships would be the first to reap the benefits. It is also possible that humans were always capable of producing these weapons but because of general tactical preference for projectile and explosive weapons they saw not the need and possibley also because a charging mac cannon and a pulse laser cannon on the same ship may overload the ships core(especially on frigate). In halo fall of reach humans show an understanding of these energy weapons and what they are(when they first meet the covenant) possibley indicating that humans may have experimented or used pulse lasers for other purposes.

Physics
Before the weapon fires, it must first charge, during the charge a sphere of light energy forms at/around the charging weapon. After it is finished charging, it expels a cyan beam of energy. According to the Halo novels, a section of the ship's shield must first drop to let the weapon fire.

Damage
The weapon is said to have reduced the UNSC frigate Commonwealth's armor in sections three and four to a quarter which would mean (as frigates are known to have 60cm-thick armor) that a pulse laser salvo is capable of melting through 45cm of titanium (A battleplate) in mere seconds. This means that pulse lasers pose a serious threat to UNSC frigates (and presumably smaller and lighter armored UNSC ships) as it only takes one salvo to melt through parts of its armor. However, it is believed that larger UNSC ships with thicker armor would have to take multiple pulse laser salvos to show the same results. In Halo 2, what is presumed to be a pulse laser is seen gutting a UNSC ship in a single blast.