When lasers were invented in 1960, they were called "a solution looking for a problem". Since then, they have become ubiquitous, finding utility in thousands of highly varied applications in every section of modern society, including consumer electronics, information technology, science, medicine, industry, law enforcement, entertainment, and the military. Fiber-optic communication using lasers is a key technology in modern communications, allowing services such as the Internet.
The first use of lasers in the daily lives of the general population was the supermarket barcode scanner, introduced in 1974. The laserdisc player, introduced in 1978, was the first successful consumer product to include a laser but the compact disc player was the first laser-equipped device to become common, beginning in 1982 followed shortly by laser printers.
Some other uses are:
Medicine: Bloodless surgery, laser healing, surgical treatment, kidney stone treatment, eye surgery, ophthalmoscopy, dentistry.
Industry: Cutting, welding, material heat treatment, marking parts, non-contact measurement of parts.
Military: Marking targets, guiding munitions, missile defense, electro-optical countermeasures (EOCM), alternative to radar, blinding troops.
Law enforcement: used for latent fingerprint detection in the forensic identification field
Research: Spectroscopy, laser ablation, laser annealing, laser scattering, laser interferometry, lidar, laser capture microdissection, fluorescence microscopy, metrology.
Product development/commercial: laser printers, optical discs (e.g. CDs and the like), barcode scanners, thermometers, laser pointers, holograms, bubblegrams.
Laser lighting displays: Laser light shows.
Cosmetic skin treatments: acne treatment, cellulite and striae reduction, and hair removal.
In 2004, excluding diode lasers, approximately 131,000 lasers were sold with a value of US$2.19 billion. In the same year, approximately 733 million diode lasers, valued at $3.20 billion, were sold.
The participants in a LARP physically portray characters in a fictional setting, improvising their characters' speech and movements somewhat like actors in improvisational theatre. This is distinct from tabletop role-playing games, where character actions are described verbally. LARPs may be played in a public or private area and may last for hours or days. There is usually no audience. Players may dress as their character and carry appropriate equipment, and the environment is sometimes decorated to resemble the setting. LARPs can be one-off events or a series of events in the same setting, and events can vary in size from a handful of players to several thousand.
Events are put on for the benefit of the players, who take on roles called player characters (PCs) that the players may create themselves or be given by the gamemasters. Players sometimes play the same character repeatedly at separate events, progressively developing the character and its relations with other characters and the setting.
Arrangers called gamemasters (GMs) determine the rules and setting of a LARP, and may also influence an event and act as referees while it is taking place. The GMs may also do the logistical work, or there may be other arrangers who handle details such as advertising the event, booking a venue, and financial management. Unlike the GM in a tabletop role-playing game, a LARP GM seldom has an overview of everything that is happening during play because numerous participants may be interacting at once. For this reason, a LARP GM's role is often less concerned with tightly maintaining a narrative or directly entertaining the players, and more with arranging the structure of the LARP before play begins and facilitating the players and crew to maintain the fictional environment during play.
Participants sometimes known as the crew may help the GMs to set up and maintain the environment of the LARP during play by acting as stagehands or playing non-player characters (NPCs) who fill out the setting. Crew typically receive more information about the setting and more direction from the GMs than players do. In a tabletop role-playing game, a GM usually plays all the NPCs, whereas in a LARP, each NPC is typically played by a separate crew member. Sometimes players are asked to play NPCs for periods of an event.
Much of play consists of interactions between characters. Some LARP scenarios primarily feature interaction between PCs. Other scenarios focus on interaction between PCs and aspects of the setting, including NPCs, that are under the direction of the GMs.