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Beam Profiler
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. Since there are many types of lasers—ultraviolet, visible, infrared, continuous wave, pulsed, high-power, low-power—there is an assortment of instrumentation for measuring laser beam profiles. No single laser beam profiler can handle every power level, pulse duration, repetition rate, wavelength, and beam size. Overview Laser beam profiling instruments measure the following quantities: * Beam width: There are over five definitions of beam width. * Beam quality: Quantified by the beam quality parameter, M2. * Beam divergence: This is a measure of the spreading of the beam with distance. * Beam profile: A beam profile is the 2D intensity plot of a beam at a given location along the beam path. A Gaussian or flat-top profile is often desired. The beam profile indicates nuisance high-order spatial modes in a l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centroid
In mathematics and physics, the centroid, also known as geometric center or center of figure, of a plane figure or solid figure is the arithmetic mean position of all the points in the figure. The same definition extends to any object in n-dimensional Euclidean space. In geometry, one often assumes uniform mass density, in which case the '' barycenter'' or ''center of mass'' coincides with the centroid. Informally, it can be understood as the point at which a cutout of the shape (with uniformly distributed mass) could be perfectly balanced on the tip of a pin. In physics, if variations in gravity are considered, then a '' center of gravity'' can be defined as the weighted mean of all points weighted by their specific weight. In geography, the centroid of a radial projection of a region of the Earth's surface to sea level is the region's geographical center. History The term "centroid" was coined in 1814. It is used as a substitute for the older terms "center of grav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knurling
Knurling is a manufacturing process, typically conducted on a lathe, whereby a pattern of straight, angled or crossed lines is rolled into the material. Knurling can also refer to material that has a knurled pattern. Etymology The terms ''knurl'' and ''knurled'' are from an earlier ''knur'' ‘knot in wood’ and the diminutive ''-le'', from Middle English ''knaur'' or ''knarre'' ‘knot in wood; twisted rock; crag’. This descends from Old English ''cnearra'' but the vowel in Middle English may have been influenced by Old Norse ''knǫrr'' ‘merchant ship’ which was known as ''cnearr'' in Old English. The modern ''gnarl'' is a back-formation of ''gnarled'' which itself is first attested in Shakespeare's works and is apparently a variant of ''knurled''. Uses Knurling produces indentations on a part of a workpiece, allowing hands or fingers to get a better grip on the knurled object than would be provided by the original smooth surface. Occasionally, the knurled pattern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionization
Ionization or ionisation is the process by which an atom or a molecule acquires a negative or positive Electric charge, charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule is called an ion. Ionization can result from the loss of an electron after collisions with subatomic particles, collisions with other atoms, molecules, electrons, positrons, protons, antiprotons, and ions, or through the interaction with electromagnetic radiation. Heterolytic bond cleavage and heterolytic substitution reactions can result in the formation of ion pairs. Ionization can occur through radioactive decay by the internal conversion process, in which an excited nucleus transfers its energy to one of the inner-shell electrons causing it to be ejected. Uses Everyday examples of gas ionization occur within a fluorescent lamp or other electrical discharge lamps. It is also used in radiation detectors such as the Geiger- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluence
In radiometry, radiant exposure or fluence is the radiant energy ''received'' by a ''surface'' per unit area, or equivalently the irradiance of a ''surface,'' integrated over time of irradiation, and spectral exposure is the radiant exposure per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength. The SI unit of radiant exposure is the joule per square metre (), while that of spectral exposure in frequency is the joule per square metre per hertz () and that of spectral exposure in wavelength is the joule per square metre per metre ()—commonly the joule per square metre per nanometre (). Mathematical definitions Radiant exposure Radiant exposure of a ''surface'', denoted ''H''e ("e" for "energetic", to avoid confusion with photometric quantities), is defined as H_\mathrm = \frac = \int_0^T E_\mathrm(t)\, \mathrmt, where *∂ is the partial derivative symbol; *''Q''e is the radiant energy; *''A'' is the area; *''T'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Cutting
Laser cutting is a technology that uses a laser to vaporize materials, resulting in a cut edge. While typically used for industrial manufacturing applications, it is now used by schools, small businesses, architecture, and hobbyists. Laser cutting works by directing the output of a high-power laser most commonly through optics. The laser optics and CNC (computer numerical control) are used to direct the laser beam to the material. A commercial laser for cutting materials uses a motion control system to follow a CNC or G-code of the pattern to be cut onto the material. The focused laser beam is directed at the material, which then either melts, burns, vaporizes away, or is blown away by a jet of gas, leaving an edge with a high-quality surface finish. History In 1965, the first production laser cutting machine was used to drilling, drill holes in diamond Die (manufacturing), dies. This machine was made by the Western Electric Engineering Research Center. In 1967, the British pi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrylate Polymers
An acrylate polymer (also known as acrylic or polyacrylate) is any of a group of polymers prepared from acrylate monomers. These plastics are noted for their transparency, resistance to breakage, and elasticity. Acrylate polymer is commonly used in cosmetics, such as nail polish, as an adhesive. History The first synthesis of acrylic polymer was reported by G. W. A. Kahlbaum in 1880. Acrylic elastomers Acrylic elastomer is a general term for a type of synthetic rubber whose primary component is acrylic acid alkylester ( ethyl or butyl ester). Acrylic elastomer possesses characteristics of heat and oil resistance, with the ability to withstand temperatures of 170–180 °C. It is used primarily for producing oil seals and packaging related to automobiles. Acrylic elastomer can generally be characterized as one of two types. "Old" types include ACM (copolymer of acrylic acid ester and 2-chloroethyl vinyl ether) containing chlorine and ANM (copolymer of acrylic acid ester ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Dioxide Laser
The carbon-dioxide laser (CO2 laser) was one of the earliest gas lasers to be developed. It was invented by C. Kumar N. Patel, Kumar Patel of Bell Labs in 1964 and is still one of the most useful types of laser. Carbon dioxide, Carbon-dioxide lasers are the highest-power continuous-wave lasers that are currently available. They are also quite efficient: the ratio of output power to Laser pumping, pump power can be as large as 20%. The CO2 laser produces a beam of infrared light with the principal wavelength bands centering on 9.6 and 10.6 Micrometre, micrometers (μm). Amplification The active laser medium (laser gain/Amplifier, amplification medium) is a gas discharge which is air- or water-cooled, depending on the power being applied. The filling gas within a sealed discharge tube consists of around 10–20% carbon dioxide (), around 10–20% nitrogen (), a few percent hydrogen () and/or xenon (Xe), with the remainder being helium (He). A different mixture is used in a ''fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photographic Plate
Photographic plates preceded film as the primary medium for capturing images in photography. These plates, made of metal or glass and coated with a light-sensitive emulsion, were integral to early photographic processes such as heliography, daguerreotypes, and photogravure. Glass plates, thinner than standard window glass, became widely used in the late 19th century for their clarity and reliability. Although largely replaced by film during the 20th century, plates continued to be used for specialised scientific and medical purposes until the late 20th century. History Glass plates were far superior to film for research-quality imaging because they were stable and less likely to bend or distort, especially in large-format frames for wide-field imaging. Early plates used the wet collodion process. The wet plate process was replaced late in the 19th century by gelatin dry plates. A view camera nicknamed "The Mammoth" weighing was built by George R. Lawrence in 1899, sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shack–Hartmann Wavefront Sensor
A Shack–Hartmann (or Hartmann–Shack) wavefront sensor (SHWFS) is an optical instrument used for characterizing an imaging system. It is a wavefront sensor commonly used in adaptive optics systems. It consists of an array of lenses (called lenslets) of the same focal length. Each is focused onto a photon sensor (typically a Charge-coupled device, CCD array or CMOS array or quad-cell). If the sensor is placed at the geometric focal plane of the lenslet, and is uniformly illuminated, then, the integrated gradient of the wavefront across the lenslet is proportional to the displacement of the centroid. Consequently, any phase Optical aberration, aberration can be approximated by a set of discrete tilts. By sampling the wavefront with an array of lenslets, all of these local tilts can be measured and the whole wavefront reconstructed. Since only tilts are measured the Shack–Hartmann cannot detect discontinuous steps in the wavefront. The design of this sensor improves upon an H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Resolution
Optical resolution describes the ability of an imaging system to resolve detail, in the object that is being imaged. An imaging system may have many individual components, including one or more lenses, and/or recording and display components. Each of these contributes (given suitable design, and adequate alignment) to the optical resolution of the system; the environment in which the imaging is done often is a further important factor. Lateral resolution Resolution depends on the distance between two distinguishable radiating points. The sections below describe the theoretical estimates of resolution, but the real values may differ. The results below are based on mathematical models of Airy discs, which assumes an adequate level of contrast. In low-contrast systems, the resolution may be much lower than predicted by the theory outlined below. Real optical systems are complex, and practical difficulties often increase the distance between distinguishable point sources. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tomography
Tomography is imaging by sections or sectioning that uses any kind of penetrating wave. The method is used in radiology, archaeology, biology, atmospheric science, geophysics, oceanography, plasma physics, materials science, cosmochemistry, astrophysics, quantum information Quantum information is the information of the state of a quantum system. It is the basic entity of study in quantum information theory, and can be manipulated using quantum information processing techniques. Quantum information refers to both t ..., and other areas of science. The word ''tomography'' is derived from Ancient Greek τόμος ''tomos'', "slice, section" and γράφω ''graphō'', "to write" or, in this context as well, "to describe." A device used in tomography is called a tomograph, while the image produced is a tomogram. In many cases, the production of these images is based on the mathematical procedure tomographic reconstruction, such as X-ray computed tomography technically being pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
