A laser was a directed-energy technology utilizing a beam of light, with all wavelengths equal and all particles in phase with one another. Due to this, the photon's motion was almost parallel, which allowed the beam to travel over a great distance with very little increase of the beam's square area, and therefore with little loss of energy per area. The word "laser" is an acronym for Light Amplification by the Stimulated Emission of Radiation. Lasers had a variety of uses in medicine, computers, mining, and power generation, such as laser-induced fusion in fusion reactors.
Some of the first lasers constructed operated by passing light through natural crystals. These "ancient lasers" then achieved a necessary excitation and emitted a laser beam. Rubindium crystals were capable of producing a laser beam, even with only a low source of light. (TOS: "Patterns of Force")
A laser beacon was part of the Starfleet equipment issued aboard the USS Enterprise. Lieutenant DeSalle used the laser beacon to attempt to signal the ship visually from the surface of Gothos. (TOS: "The Squire of Gothos")
Laser weapons also existed, such as the advanced laser pistols and laser cannons used by Starfleet in the 2250s, and the high-energy X-ray lasers mounted aboard Talarian warships. (TOS: "The Cage"; TNG: "Suddenly Human")
According to Lt. Sulu in 2269, the laser weapons the Federation possessed were a more advanced model than the laser setting of the Slaver weapon, and their laser had been more powerful for the last century. (TAS: "The Slaver Weapon")
The Atlec used laser weapons on their ships and once targeted them on the Enterprise-D in an attempt to acquire the Straleb Jewel of Thesia and Thadiun Okona. Picard noted that such lasers would not even penetrate their navigation shields. Starfleet regulations required that a vessel targeted with laser weapons go to yellow alert; it was considered a very old regulation. (TNG: "The Outrageous Okona")
When Chief Miles O'Brien introduced the game of darts at Quark's Bar, Grill, Gaming House and Holosuite Arcade, Quark failed to understand its appeal because it did not include anything like lasers or holograms. (DS9: "Visionary")
The 24th century Federation belief that lasers were obsolete weapons was proved wrong in a catastrophic fashion on the Federation's first contact with the Borg, as the cutting beam aboard a Borg cube proved to be capable of destroying Federation starships with ease. (TNG: "Q Who", "The Best of Both Worlds"; DS9: "Emissary"; Star Trek: First Contact)
Zefram Cochrane told Commander Riker that he had a hangover either from the whiskey he drank or because of Riker's laser beam, referring to the phaser he'd been stunned with earlier. (Star Trek: First Contact)
|Tools: autosuture • bone-knitting laser • laser beacon • laser core sampler • laser drill • laser scalpel • laser scanner • laser torch • laser welder • microscope laser • miniature laser • nanopulse laser • tri-laser connector|
|Weapons: Artonian laser • cutting beam • laser cannon • laser detonator • laser pistol • pulse laser • x-ray laser|
|Other: laser fusion initiator • laser micrometer • LIDAR • laser pulse system|
The McDonald's video communicator comic "Votec's Freedom" suggests that Starfleet continued to refine laser technology into the 2270s, as Spock cuts a prisoner's chains with his "new ultra laser."
James Blish's conversion of "Patterns of Force" to prose form in Star Trek 12 had Kirk explain to Isak that crystalline rubindium-based laser cutting torches were not weapons, as they had extremely short ranges. Since the Star Fleet Medical Reference Manual lists rubindium as being radioactive, laser cutting torches based upon it can also be presumed to have short useful life expectancies and therefore to be useless as weapons, as prolonged usage would quickly decrystallize the rubindium in the laser element.