Laser

A laser is a device that emits a narrow, monochromatic beam of light with a well-defined wavelength. The word laser is derived from the acronym for Light Amplification by Stimulated Emission of Radiation; it uses electrical, optical, or chemical means to excite atoms in an active medium (light-emitting material), producing a powerful light pulse, and a specialized mirror system to collimate, focus, and amplify the beam.

Humanity first developed laser technology in May 1960, when the first solid-state ruby laser was built and tested by Theodore Maiman at Hughes Research Laboratories. By the 21st century, lasers had become a multi-billion dollar industry. Civilian applications included reading digital storage disks, reading bar codes, or in handheld devices such as laser pointers. Lasers used in medicine are used for internal surgery and cosmetic applications. In manufacturing, they were used for precision cutting, welding, and other functions. They were also commonly used in various fields in science, especially spectroscopy. Lasers were also used by the military for target identification and weapons guidance systems. All of these uses are presumably just as widespread five centuries later.

The use of laser technology for offensive purposes was still in its infancy during the 21st century, mostly specializing in ordnance threat neutralization, but in recent times the UNSC has developed several laser-based weapons. The Covenant, on the other hand, has been using laser-based weaponry for far longer.

Applications

 * The Covenant uses pulse laser turrets and other directed energy weapons as the standard armament of all of its warships, from the small missionary ships to the titanic assault carriers, supplementing more devastating Plasma turrets. These weapons use the chemical reaction between hydrogen and fluoride to provide its energy.
 * The UNSC has been slower to adapt lasers to combat uses, though laser turrets are equipped to Office of Naval Intelligence Prowlers and the UNSC is issuing the M6 Spartan Laser into frontline service . Though not a weapon, the laser designator, the H-165 and H-295 target locators uses a laser beam to designate targets and measure the distance between itself and an object. The Laser aiming module also is used to ensure targeting accuracy.
 * Some Kig-Yar firearms use lasers for projectiles.