<unk> s range in size from microscopic diode<unk> s (top) with numerous applications, to football field sized neodymium glass<unk> s (bottom) used for inertial confinement fusion, nuclear weapons research and other high energy density physics experiments. When<unk> s 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<unk> s is a key technology in modern communications, allowing services such as the Internet. The first widely noticeable use of<unk> s was the supermarket barcode scanner, introduced in 1974. The<unk> disc player, introduced in 1978, was the first successful consumer product to include a<unk>  but the compact disc player was the first<unk> -equipped device to become common, beginning in 1982 followed shortly by<unk>  printers. Some other uses are: * Communications: besides fiber-optic communication,<unk> s are used for free-space optical communication, including<unk>  communication in space. * Medicine: see below. * Industry: cutting including converting thin materials, welding, material heat treatment, marking parts (engraving and bonding), additive manufacturing or 3D printing processes such as selective<unk>  sintering and selective<unk>  melting, non-contact measurement of parts and 3D scanning, and<unk>  cleaning. * Military: marking targets, guiding munitions, missile defense, electro-optical countermeasures (EOCM), lidar, blinding troops, firearms sight. See below * Law enforcement: LIDAR traffic enforcement.<unk> s are used for latent fingerprint detection in the forensic identification field * Research: spectroscopy,<unk>  ablation,<unk>  annealing,<unk>  scattering,<unk>  interferometry, lidar,<unk>  capture microdissection, fluorescence microscopy, metrology,<unk>  cooling. * Commercial products:<unk>  printers, barcode scanners, thermometers,<unk>  pointers, holograms, bubblegrams. * Entertainment: optical discs,<unk>  lighting displays,<unk>  turntables In 2004, excluding diode<unk> s, approximately 131,000<unk> s were sold with a value of US$2.19 billion. In the same year, approximately 733 million diode<unk> s, valued at $3.20 billion, were sold. In medicine<unk> s have many uses in medicine, including<unk>  surgery (particularly eye surgery),<unk>  healing, kidney stone treatment, ophthalmoscopy, and cosmetic skin treatments such as acne treatment, cellulite and striae reduction, and hair removal.<unk> s are used to treat cancer by shrinking or destroying tumors or precancerous growths. They are most commonly used to treat superficial cancers that are on the surface of the body or the lining of internal organs. They are used to treat basal cell skin cancer and the very early stages of others like cervical, penile, vaginal, vulvar, and non-small cell lung cancer.<unk>  therapy is often combined with other treatments, such as surgery, chemotherapy, or radiation therapy.<unk> -induced interstitial thermotherapy (LITT), or interstitial<unk>  photocoagulation, uses<unk> s to treat some cancers using hyperthermia, which uses heat to shrink tumors by damaging or killing cancer cells.<unk> s are more precise than traditional surgery methods and cause less damage, pain, bleeding, swelling, and scarring. A disadvantage is that surgeons must have specialized training. It may be more expensive than other treatments. As weapons A<unk>  weapon is a<unk>  that is used as a directed-energy weapon. Tactical High Energy weapon has been used to shoot down rockets and artillery shells. Hobbies In recent years, some hobbyists have taken interests in<unk> s.<unk> s used by hobbyists are generally of class IIIa or IIIb (see Safety), although some have made their own class IV types. However, compared to other hobbyists,<unk>  hobbyists are far less common, due to the cost and potential dangers involved. Due to the cost of<unk> s, some hobbyists use inexpensive means to obtain<unk> s, such as salvaging<unk>  diodes from broken DVD players (red), Blu-ray players (violet), or even higher power<unk>  diodes from CD or DVD burners. Hobbyists also have been taking surplus pulsed<unk> s from retired military applications and modifying them for pulsed holography. Pulsed Ruby and pulsed YAG<unk> s have been used. Examples by power<unk>  application in astronomical adaptive optics imaging Different applications need<unk> s with different output powers.<unk> s that produce a continuous beam or a series of short pulses can be compared on the basis of their average power.<unk> s that produce pulses can also be characterized based on the peak power of each pulse. The peak power of a pulsed<unk>  is many orders of magnitude greater than its average power. The average output power is always less than the power consumed. + The continuous or average power required for some uses: Power Use<unk>  pointers CD-ROM drive DVD player or DVD-ROM drive High-speed CD-RW burner Consumer 16× DVD-R burner DVD 24× dual-layer recording Green<unk>  in Holographic Versatile Disc prototype development Output of the majority of commercially available solid-state<unk> s used for micro machining Typical sealed CO2 surgical<unk> s Typical sealed CO2<unk> s used in industrial<unk>  cutting Examples of pulsed systems with high peak power: * 700 TW (700×1012 W) – National Ignition Facility, a 192-beam, 1.8-megajoule<unk>  system adjoining a 10-meter-diameter target chamber * 10 PW (10×1015 W) – world's most powerful<unk>  as of 2019, located at the ELI-NP facility in Măgurele, Romania.
Laser
Nd:YAG laser
Comedo extraction
Whitfield's ointment
Oculoplastics
Crusaid
Eyepatch
Contact lens