Laser

Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography.

Laser cutting is a technology that uses a laser to slice materials.

Spatial coherence also allows a laser beam to stay narrow over great distances (collimation), enabling applications such as laser pointers and lidar.

Lidar (, called LIDAR, LiDAR, and LADAR) is a surveying method that measures distance to a target by illuminating the target with laser light and measuring the reflected light with a sensor.

The term "laser" originated as an acronym for "light amplification by stimulated emission of radiation".

The most common capitalization scheme seen with acronyms is all-uppercase (all-caps), except for those few that have linguistically taken on an identity as regular words, with the acronymous etymology of the words fading into the background of common knowledge, such as has occurred with the words "scuba", "laser", and "radar"—these are known as anacronyms.

Spatial coherence also allows a laser beam to stay narrow over great distances (collimation), enabling applications such as laser pointers and lidar.

A laser pointer or laser pen is a small handheld device with a power source (usually a battery) and a laser diode emitting a very narrow coherent low-powered laser beam of visible light, intended to be used to highlight something of interest by illuminating it with a small bright spot of colored light.

Lasers are used in optical disk drives, laser printers, barcode scanners, DNA sequencing instruments, fiber-optic and free-space optical communication, laser surgery and skin treatments, cutting and welding materials, military and law enforcement devices for marking targets and measuring range and speed, and in laser lighting displays for entertainment.

In computing, an optical disc drive (ODD) is a disc drive that uses laser light or electromagnetic waves within or near the visible light spectrum as part of the process of reading or writing data to or from optical discs.

Lasers are used in optical disk drives, laser printers, barcode scanners, DNA sequencing instruments, fiber-optic and free-space optical communication, laser surgery and skin treatments, cutting and welding materials, military and law enforcement devices for marking targets and measuring range and speed, and in laser lighting displays for entertainment.

It produces high-quality text and graphics (and moderate-quality photographs) by repeatedly passing a laser beam back and forth over a negatively charged cylinder called a "drum" to define a differentially charged image.

Lasers are used in optical disk drives, laser printers, barcode scanners, DNA sequencing instruments, fiber-optic and free-space optical communication, laser surgery and skin treatments, cutting and welding materials, military and law enforcement devices for marking targets and measuring range and speed, and in laser lighting displays for entertainment.

A laser lighting display or laser light show involves the use of laser light to entertain an audience.

Lasers are used in optical disk drives, laser printers, barcode scanners, DNA sequencing instruments, fiber-optic and free-space optical communication, laser surgery and skin treatments, cutting and welding materials, military and law enforcement devices for marking targets and measuring range and speed, and in laser lighting displays for entertainment.

Laser beam welding (LBW) is a welding technique used to join pieces of metal or thermoplastics through the use of a laser.

Lasers are used in optical disk drives, laser printers, barcode scanners, DNA sequencing instruments, fiber-optic and free-space optical communication, laser surgery and skin treatments, cutting and welding materials, military and law enforcement devices for marking targets and measuring range and speed, and in laser lighting displays for entertainment.

A laser rangefinder is a rangefinder that uses a laser beam to determine the distance to an object.

Lasers are used in optical disk drives, laser printers, barcode scanners, DNA sequencing instruments, fiber-optic and free-space optical communication, laser surgery and skin treatments, cutting and welding materials, military and law enforcement devices for marking targets and measuring range and speed, and in laser lighting displays for entertainment.

Laser scanners work the same way as pen-type readers except that they use a laser beam as the light source and typically employ either a reciprocating mirror or a rotating prism to scan the laser beam back and forth across the barcode.

A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation.

An optical amplifier may be thought of as a laser without an optical cavity, or one in which feedback from the cavity is suppressed.

For the gain medium to amplify light, it needs to be supplied with energy in a process called pumping.

Laser pumping is the act of energy transfer from an external source into the gain medium of a laser.

A laser consists of a gain medium, a mechanism to energize it, and something to provide optical feedback.

The active laser medium (also called gain medium or lasing medium) is the source of optical gain within a laser.

A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation.

Such a gain medium, along with an optical resonator, is at the heart of a laser or maser.

In this usage, the term "light" includes electromagnetic radiation of any frequency, not only visible light, hence the terms infrared laser, ultraviolet laser, X-ray laser and gamma-ray laser.

A gamma-ray laser, or graser, would produce coherent gamma rays, just as an ordinary laser produces coherent rays of visible light.

Temporal (or longitudinal) coherence implies a polarized wave at a single frequency, whose phase is correlated over a relatively great distance (the coherence length) along the beam.

Especially impacted are technologies such as lasers, wireless and optical fiber telecommunications, and radar.

The most common type of laser uses feedback from an optical cavity—a pair of mirrors on either end of the gain medium.

Optical cavities are a major component of lasers, surrounding the gain medium and providing feedback of the laser light.

Further use of the words laser and maser in an extended sense, not referring to laser technology or devices, can be seen in usages such as astrophysical maser and atom laser.

Like a laser, the emission from a maser is stimulated (or seeded) and monochromatic, having the frequency corresponding to the energy difference between two quantum-mechanical energy levels of the species in the gain medium which have been pumped into a non-thermal population distribution.

Because the microwave predecessor of the laser, the maser, was developed first, devices of this sort operating at microwave and radio frequencies are referred to as "masers" rather than "microwave lasers" or "radio lasers".

The laser works by the same principle as the maser, but produces higher frequency coherent radiation at visible wavelengths.

Spatial coherence also allows a laser beam to stay narrow over great distances (collimation), enabling applications such as laser pointers and lidar.

Laser light from gas or crystal lasers is highly collimated because it is formed in an optical cavity between two parallel mirrors which constrain the light to a path perpendicular to the surfaces of the mirrors.

Lasers are used in optical disk drives, laser printers, barcode scanners, DNA sequencing instruments, fiber-optic and free-space optical communication, laser surgery and skin treatments, cutting and welding materials, military and law enforcement devices for marking targets and measuring range and speed, and in laser lighting displays for entertainment.

The invention of lasers in the 1960s revolutionized free space optics.

The minimum pump power needed to begin laser action is called the lasing threshold.

The lasing threshold is the lowest excitation level at which a laser's output is dominated by stimulated emission rather than by spontaneous emission.

When an electron absorbs energy either from light (photons) or heat (phonons), it receives that incident quantum of energy.

The photon concept has led to momentous advances in experimental and theoretical physics, including lasers, Bose–Einstein condensation, quantum field theory, and the probabilistic interpretation of quantum mechanics.

Some lasers use a separate injection seeder to start the process off with a beam that is already highly coherent.

Injection seeders are devices that direct the output of small "seed" lasers into the cavity of a much larger laser to stabilize the latter's output.

A laser beam profiler is used to measure the intensity profile, width, and divergence of laser beams.

A laser beam profiler captures, displays, and records the spatial intensity profile of a laser beam at a particular plane transverse to the beam propagation path.