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A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term "laser" originated as an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow.
A printed circuit board (PCB) mechanically supports and electrically connects electrical or electronic components using conductive tracks, pads and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. Components are generally soldered onto the PCB to both electrically connect and mechanically fasten them to it.
A laser diode, (LD), injection laser diode (ILD), or diode laser is a semiconductor device similar to a light-emitting diode in which a diode pumped directly with electrical current can create lasing conditions at the diode's junction. Laser diodes can directly convert electrical energy into light. Driven by voltage, the doped p-n-transition allows for recombination of an electron with a hole. Due to the drop of the electron from a higher energy level to a lower one, radiation, in the form of an emitted photon is generated. This is spontaneous emission. Stimulated emission can be produced when the process is continued and further generate light with the same phase, coherence and wavelength.
The Boeing YAL-1 Airborne Laser Testbed weapons system was a megawatt-class chemical oxygen iodine laser (COIL) mounted inside a modified military aircraft same as the Boeing 747-400F. It was primarily designed as a missile defense system to destroy tactical ballistic missiles (TBMs) while in boost phase. The aircraft was designated YAL-1A in 2004 by the U.S. Department of Defense.
The term biophotonics denotes a combination of biology and photonics, with photonics being the science and technology of generation, manipulation, and detection of photons, quantum units of light. Photonics is related to electronics and photons. Photons play a central role in information technologies, such as fiber optics, the way electrons do in electronics.
In color reproduction, including computer graphics and photography, the gamut, or color gamut, is a certain complete subset of colors. The most common usage refers to the subset of colors which can be accurately represented in a given circumstance, such as within a given color space or by a certain output device.
A close-in weapon system is a point-defense weapon system for detecting and destroying short-range incoming missiles and enemy aircraft which have penetrated the outer defenses, typically mounted shipboard in a naval capacity. Nearly all classes of larger modern warships are equipped with some kind of CIWS device.
A video projector is an image projector that receives a video signal and projects the corresponding image on a projection screen using a lens system. Video projectors use a very bright Ultra-high-performance lamp, Xenon arc lamp, LED or solid state blue, RB, RGB or remote fiber optic RGB lasers to provide the illumination required to project the image, and most modern ones can correct any curves, blurriness, and other inconsistencies through manual settings. If a blue laser is used, a phosphor wheel is used to turn blue light into white light, which is also the case with white LEDs. A wheel is used in order to prolong the lifespan of the phosphor, as it is degraded by the heat generated by the laser diode. Remote fiber optic RGB laser racks can be placed far away from the projector, and several racks can be housed in a single, central room. Each projector can use up to two racks, and several monochrome lasers are mounted on each rack, the light of which is mixed and transmitted to the projector booth using optical fibers. Projectors using RB lasers use a blue laser with a phosphor wheel in conjunction with a conventional solid state red laser.
Laser beam welding (LBW) is a welding technique used to join pieces of metal or thermoplastics through the use of a laser. The beam provides a concentrated heat source, allowing for narrow, deep welds and high welding rates. The process is frequently used in high volume applications using automation, as in the automotive industry. It is based on keyhole or penetration mode welding.
A microtome is a tool used to cut extremely thin slices of material, known as sections. Important in science, microtomes are used in microscopy, allowing for the preparation of samples for observation under transmitted light or electron radiation.
An ion laser is a gas laser that uses an ionized gas as its lasing medium. Like other gas lasers, ion lasers feature a sealed cavity containing the laser medium and mirrors forming a Fabry–Pérot resonator. Unlike helium–neon lasers, the energy level transitions that contribute to laser action come from ions. Because of the large amount of energy required to excite the ionic transitions used in ion lasers, the required current is much greater, and as a result all but the smallest ion lasers are water-cooled. A small air-cooled ion laser might produce, for example, 130 milliwatts of output light with a tube current of about 10 amperes and a voltage of 105 volts. Since one ampere times one volt is one watt, this is an electrical power input of about one kilowatt. Subtracting the (desirable) light output of 130 mW from power input, this leaves the large amount of waste heat of nearly one kW. This has to be dissipated by the cooling system. In other words, the power efficiency is very low.
The Advanced Tactical Laser (ATL) program was a US military program to mount a high energy laser weapon on an aircraft, initially the AC-130 gunship, for use against ground targets in urban or other areas where minimizing collateral damage is important. The laser was a 100 kilowatt-class chemical oxygen iodine laser (COIL). It was expected to have a tactical range of approximately twenty kilometers and weigh about 5,000–7,000 kg. This program is distinct from the Airborne Laser, which was a much larger system designed to destroy enemy missiles in the boost phase.
A solid-state laser is a laser that uses a gain medium that is a solid, rather than a liquid as in dye lasers or a gas as in gas lasers. Semiconductor-based lasers are also in the solid state, but are generally considered as a separate class from solid-state lasers.
A dazzler is a non-lethal weapon which uses intense directed radiation to temporarily disable its target with flash blindness. Targets can include sensors or human vision.
A laser weapon is a directed-energy weapon based on lasers. After decades of R&D, as of January 2020 directed-energy weapons including lasers are still at the experimental stage and it remains to be seen if or when they will be deployed as practical, high-performance military weapons. Atmospheric thermal blooming has been a major problem, still mostly unsolved and worsened if there is fog, smoke, dust, rain, snow, smog, foam, or purposely dispersed obscurant chemicals in the air. Essentially, a laser generates a beam of light which needs clear air, or a vacuum to work without thermal blooming. Laser and other directed-energy weapons have been a staple in science fiction since their inception however.
Counter rocket, artillery, and mortar, abbreviated C-RAM or counter-RAM, is a set of systems used to detect and/or destroy incoming rockets, artillery, and mortar rounds in the air before they hit their ground targets, or simply provide early warning.
Thick-film technology is used to produce electronic devices/modules such as surface mount devices modules, hybrid integrated circuits, heating elements, integrated passive devices and sensors. Main manufacturing technique is screen printing (stenciling), which additionally to manufacturing electronic devices can also be used for various graphic reproduction targets. The technique is known in it's basic form about thousand years - already used during great Chinese dynasties. It became one of the key manufacturing/miniaturisation techniques of electronic devices/modules during 1950s. Typical film thickness - manufactured with thick film manufacturing processes for electronic devices - is 0.0001 - 0.1 mm.
The watt is a unit of power. In the International System of Units (SI) it is defined as a derived unit of 1 joule per second, and is used to quantify the rate of energy transfer. In SI base units, the watt is described as kg⋅m2⋅s−3. The watt is named after James Watt, an 18th-century Scottish inventor.
References
- ↑ Advanced Thermal Management Materials. Springer. p. 132. ISBN 978-1-4614-1962-4.
- ↑ Slawomir Sujecki (2015). Photonics Modeling and Design. CRC Press. p. 197.