A laser weapon is a type of directed-energy weapon that uses lasers to inflict damage. Despite decades of research and development, as of January 2020, directed-energy weapons, including lasers, remain at the experimental stage. Whether they will be deployed as practical, high-performance military weapons remains to be seen. One of the major issues with laser weapons is atmospheric thermal blooming, which is still largely unsolved. This issue is exacerbated when there is fog, smoke, dust, rain, snow, smog, foam, or purposely dispersed obscurant chemicals present. In essence, a laser generates a beam of light that requires clear air or a vacuum to operate.
Several types of laser have been identified as having the potential to be used as incapacitating non-lethal weapons. They can cause temporary or permanent vision loss when directed at the eyes. The extent, nature, and duration of visual impairment resulting from exposure to laser light depend on various factors, such as the laser's power, wavelength(s), collimation of the beam, orientation of the beam, and duration of exposure. Even lasers with a power output of less than one watt can cause immediate and permanent vision loss under certain conditions, making them potential non-lethal but incapacitating weapons. However, the use of such lasers is morally controversial due to the extreme handicap that laser-induced blindness represents. The Protocol on Blinding Laser Weapons bans the use of weapons designed to cause permanent blindness.
Weapons designed to cause temporary blindness, known as dazzlers, are used by military and sometimes law enforcement organizations. Incidents of pilots being exposed to lasers while flying have prompted aviation authorities to implement special procedures to deal with such hazards. Laser weapons capable of directly damaging or destroying a target in combat are still in the experimental stage. The general idea of laser-beam weaponry is to hit a target with a train of brief pulses of light. The power needed to project a high-powered laser beam of this kind is beyond the limit of current mobile power technology, thus favoring chemically powered gas dynamic lasers. Example experimental systems included MIRACL and the Tactical High Energy Laser, which are now discontinued. The United States Navy has tested the very short-range (1 mile), 30-kW Laser Weapon System or LaWS to be used against targets like small UAVs, rocket-propelled grenades, and visible motorboat or helicopter engines. It has been defined as "six welding lasers strapped together." A 60 kW system, HELIOS, is being developed for destroyer-class ships as of 2020.