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Fiber Disk Laser
A fiber disk laser is a fiber laser with transverse delivery of the pump light. They are characterized by the pump beam not being parallel to the active core of the optical fiber (as in a double-clad fiber), but directed to the coil of the fiber at an angle (usually, between 10 and 40 degrees). This allows use of the specific shape of the pump beam emitted by the laser diode, providing the efficient use of the pump. Fiber disk lasers should not be confused with the LaserDiscs (disk-shaped devices for storage and reading of information with laser beam) nor the disk laser or "active mirror", which is a laser with a thin active layer where the heat sink is realized in a direction opposite to that of propagation of the output beam. Realizations of fiber disk lasers First disk lasers were developed in the Institute for Laser Science, Japan. Several realizations of fiber disk lasers were reported. The fiber disk laser is so named because the fiber is tightly coiled. Typically, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiber Laser
A fiber laser (or fibre laser in British English) is a laser in which the active gain medium is an optical fiber doped with rare-earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium and holmium. They are related to doped fiber amplifiers, which provide light amplification without lasing. Fiber nonlinearities, such as stimulated Raman scattering or four-wave mixing can also provide gain and thus serve as gain media for a fiber laser. Advantages and applications An advantage of fiber lasers over other types of lasers is that the laser light is both generated and delivered by an inherently flexible medium, which allows easier delivery to the focusing location and target. This can be important for laser cutting, welding, and folding of metals and polymers. Another advantage is high output power compared to other types of laser. Fiber lasers can have active regions several kilometers long, and so can provide very high optical gain. They ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Pumping
Laser pumping is the act of energy transfer from an external source into the gain medium of a laser. The energy is absorbed in the medium, producing excited states in its atoms. When the number of particles in one excited state exceeds the number of particles in the ground state or a less-excited state, population inversion is achieved. In this condition, the mechanism of stimulated emission can take place and the medium can act as a laser or an optical amplifier. The pump power must be higher than the lasing threshold of the laser. The pump energy is usually provided in the form of light or electric current, but more exotic sources have been used, such as chemical or nuclear reactions. Optical pumping Pumping cavities A laser pumped with an arc lamp or a flashlamp is usually pumped through the lateral wall of the lasing medium, which is often in the form of a crystal rod containing a metallic impurity or a glass tube containing a liquid dye, in a condition known as "side-pum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Fiber
An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparency and translucency, transparent fiber made by Drawing (manufacturing), drawing glass (silica) or plastic to a diameter slightly thicker than that of a Hair's breadth, human hair. Optical fibers are used most often as a means to transmit light between the two ends of the fiber and find wide usage in fiber-optic communications, where they permit transmission over longer distances and at higher Bandwidth (computing), bandwidths (data transfer rates) than electrical cables. Fibers are used instead of metal wires because signals travel along them with less Attenuation, loss; in addition, fibers are immune to electromagnetic interference, a problem from which metal wires suffer. Fibers are also used for Illumination (lighting), illumination and imaging, and are often wrapped in bundles so they may be used to carry light into, or images out of confined spaces, as in the case of a fiberscope. Special ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double-clad Fiber
Double-clad fiber (DCF) is a class of optical fiber with a structure consisting of three layers of optical material instead of the usual two. The inner-most layer is called the '' core''. It is surrounded by the ''inner cladding'', which is surrounded by the ''outer cladding''. The three layers are made of materials with different refractive indices. There are two different kinds of double-clad fibers. The first was developed early in optical fiber history with the purpose of engineering the dispersion of optical fibers. In these fibers, the core carries the majority of the light, and the inner and outer cladding alter the waveguide dispersion of the core-guided signal. The second kind of fiber was developed in the late 1980s for use with high power fiber amplifiers and fiber lasers. In these fibers, the core is doped with active dopant material; it both guides and amplifies the signal light. The inner cladding and core together guide the pump light, which provides the energ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Diode
The laser diode chip removed and placed on the eye of a needle for scale A laser diode (LD, also injection laser diode or 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. 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 generates light with the same phase, coherence and wavelength. The choice of the semiconductor material determines the wavelength of the emitted beam, which in today's laser diodes range from infra-red to the UV spectrum. Laser diodes are the most common type of lasers produced, with a wide range of uses that include fiber optic c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LaserDisc
The LaserDisc (LD) is a home video format and the first commercial optical disc storage medium, initially licensed, sold and marketed as DiscoVision, MCA DiscoVision (also known simply as "DiscoVision") in the United States in 1978. Its diameter typically spans . Unlike most optical disc standards, LaserDisc is not fully Digital data, digital, and instead requires the use of analog video signals. Although the format was capable of offering higher-quality video and audio than its consumer rivals—VHS and Betamax videotape—LaserDisc never managed to gain widespread use in North America, largely due to high costs for the players and the inability to record TV programmes. It eventually did gain some traction in that region and became somewhat popular in the 1990s. It was not a popular format in Europe and Australia. By contrast, the format was much more popular in Japan and in the more affluent regions of Southeast Asia, such as Hong Kong, Singapore and Malaysia, and was the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk Laser
A disk laser or active mirror (Fig.1) is a type of diode pumped solid-state laser characterized by a heat sink and laser output that are realized on opposite sides of a thin layer of active gain medium. Despite their name, disk lasers do not have to be circular; other shapes have also been tried. The thickness of the disk is considerably smaller than the laser beam diameter. Initially, this laser cavity configuration had been proposed and realized experimentally for thin slice semiconductor lasers. The disk laser concepts allow very high average and peak powers due to its large area, leading to moderate power densities on the active material. Active mirrors and disk lasers Initially, disk lasers were called ''active mirrors'', because the gain medium of a disk laser is essentially an optical mirror with reflection coefficient greater than unity. An active mirror is a thin disk-shaped double-pass optical amplifier. The first active mirrors were developed in the Laboratory for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Institute For Laser Science
The Institute for Laser Science is a department of the University of Electro Communications, located near Tokyo, Japan. History and achievements Established in 1980, the Institute specializes mainly in improving the performance of gas lasers, especially excimer lasers. Between 1990 and 2005, the Institute developed fiber disk lasers, disk laser ( active mirror) and the concept of power scaling. Ultra-low loss mirror was developed aiming application for high power lasers (1995). Since 2000, its main research directions have been in the areas of solid state lasers, fiber lasers and ceramics. Since then, the Institute has carried out experiments with quantum reflection of cold excited neon atoms from silicon surfaces. The institute has also performed the first experiments with quantum reflection of cold atoms from Si surface and, in particular, ridged mirrors for cold atoms and the interpretation as Zeno effect. In 2004, the Institute developed the first microch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Physics (journal)
''Laser Physics'' is a monthly peer-reviewed scientific journal covering research on the physics and technology of lasers and their applications. It is owned and editorially managed by Astro Ltd. and published on their behalf by IOP Publishing. The journal was established in 1990 with Alexander M. Prokhorov as founding editor-in-chief until 2002. The current editor-in-chief is Vanderlei S. Bagnato. It is a sister journal to ''Laser Physics Letters''. Abstracting and indexing The journal is abstracted and indexed in: *Science Citation Index Expanded *Current Contents *Scopus * INSPEC History The journal was published by MAIK Nauka/Interperiodica from 1991 to 2005, by Springer Science+Business Media from 2006 to 2012, and since then by IOP Publishing. Its sister journal, ''Laser Physics Letters'', was established in 2004. See also *Laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Welding
Welding is a fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing fusion. Welding is distinct from lower temperature techniques such as brazing and soldering, which do not melt the base metal (parent metal). In addition to melting the base metal, a filler material is typically added to the joint to form a pool of molten material (the weld pool) that cools to form a joint that, based on weld configuration (butt, full penetration, fillet, etc.), can be stronger than the base material. Pressure may also be used in conjunction with heat or by itself to produce a weld. Welding also requires a form of shield to protect the filler metals or melted metals from being contaminated or oxidized. Many different energy sources can be used for welding, including a gas flame (chemical), an electric arc (electrical), a laser, an electron beam, friction, and ultrasound. While often an i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pattern Welding
Pattern welding is the practice in sword and knife making of forming a blade of several metal pieces of differing composition that are forge welding, forge-welded together and twisted and manipulated to form a pattern. Often mistakenly called Damascus steel, blades forged in this manner often display bands of slightly different patterning along their entire length. These bands can be highlighted for cosmetic purposes by proper polishing or acid industrial etching, etching. Pattern welding was an outgrowth of laminated steel blade, laminated or piled steel, a similar technique used to combine steels of different carbon contents, providing a desired mix of hardness and toughness. Although modern steelmaking processes negate the need to blend different steels, pattern welded steel is still used by custom knifemakers for the cosmetic effects it produces. History Pattern welding developed out of the necessarily complex process of making blades that were both hardness, hard and tough ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
