If no suitable medium for a single-layer coating can be found, or if anti-reflective properties are required for a very broad wavelength range (or for different wavelength ranges simultaneously, or for different angles of incidence), more complicated designs may be used, which usually have to be found using numerical techniques, implemented in suitable thin-film design software. A general trade-off of such multilayer designs is between a low residual reflectance and a large bandwidth. So-called V coatings have a high performance only in a narrow bandwidth (order of 10 nm), whereas broadband coatings offer moderate performance but in a wide wavelength range.

There was no chair of applied mechanism and applied mechanics at Cambridge until 1875, and no chair of engineering at Oxford until 1907. Germany established technical universities earlier.[15]

Shanghai Optics provides custom anti-reflection coatings with appropriate materials and optimized configuration on a substrate material specified by the customer, with specified transmittance and a specified wavelength region.

engineering影响因子

Only a decade after the successful flights by the Wright brothers, there was extensive development of aeronautical engineering through development of military aircraft that were used in World War I. Meanwhile, research to provide fundamental background science continued by combining theoretical physics with experiments.

Later, as the design of civilian structures, such as bridges and buildings, matured as a technical discipline, the term civil engineering[4] entered the lexicon as a way to distinguish between those specializing in the construction of such non-military projects and those involved in the discipline of military engineering.

Anti-Reflection (AR) coatings are one of widely used optical thin-film coatings that can be applied to the surfaces of optical elements to reduce reflection and to improve transmittance within some spectral region. We provide AR coatings with appropriate materials and optimized configuration on a substrate material specified by the customer, with specified transmittance and a specified wavelength region.

The first steam engine was built in 1698 by Thomas Savery.[12] The development of this device gave rise to the Industrial Revolution in the coming decades, allowing for the beginnings of mass production.

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Anti-reflection coatings [3] are often used for optical components in order to reduce optical losses and sometimes also the detrimental influence of reflected beams. The residual reflectance for a given wavelength and angle of incidence is often of the order of 0.2%, or less (in a limited bandwidth) with careful optimization. For application on prescription glasses, the achievable suppression of reflections is significantly lower, since the coating must operate in a wide wavelength range and for a wide range of incidence angles. AR coatings are also used on laser crystals and nonlinear crystals. In such cases, additional challenges can arise from anisotropic thermal expansion e.g. of lithium triborate (LBO) crystals.

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A wide range of possibilities arises from gradient index coatings (or graded-index coatings) [2, 3, 11], where the composition of a layer material is gradually varied (as in rugate filters). In the simplest case, a smooth index transition between two optical materials over a length scale of a few wavelengths can suppress fairly well the reflection over a wide spectral and angular range. This is difficult to realize, however, for surfaces next to air, since all solid materials have a refractive index significantly different from that of air. One solution is to use nanooptics in the form of sub-wavelength pyramid structures or the like (moth eye structure), see e.g. Refs.  [1], [2] and [7]. Such structures (which can be called photonic metamaterials) imitate a smooth transition of the refractive index to 1 by smoothly reducing the amount of solid material in a plane parallel to the surface. However, there are also solutions without nanooptics, in particular the integration of gradient index layers into a multilayer coating. This allows for good broadband anti-reflection properties in a wide angular range without using materials with a very small refractive index.

Apart from those properties, the tolerance to growth errors may also be of interest: there are sophisticated coating designs which reach a high performance only for very precise manufacturing. The growth error tolerance is therefore an important aspect to be considered in the design.

Multilayer anti-reflection coatings are often applied to optical glasses and crystals, but they can also be used for plastic optics.

Note that there are also anti-glare surfaces, which suppress reflections in an entirely different way: by diffuse scattering from a microscopically rough surface. Such surfaces are suitable e.g. for some displays and viewing ports, but normally not for laser applications, and should be carefully distinguished from anti-reflection surfaces.

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We produce a wide range of AR coatings with different designs like V coatings and broadband coatings, covering the spectral range from 300–6000 nm. Custom AR coatings are not a problem – we design and manufacture on site, all part of our rapid turnaround service, we like to think we offer the best service out there, typical one week!

In most cases, the basic principle of operation is that reflected waves from different optical interfaces largely cancel each other by destructive interference.

Aeronautical engineering deals with aircraft design process design while aerospace engineering is a more modern term that expands the reach of the discipline by including spacecraft design. Its origins can be traced back to the aviation pioneers around the start of the 20th century although the work of Sir George Cayley has recently been dated as being from the last decade of the 18th century. Early knowledge of aeronautical engineering was largely empirical with some concepts and skills imported from other branches of engineering.[16]

engineering期刊

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In the simplest case, an anti-reflection thin-film coating designed for normal incidence consists of a single quarter-wave layer of a material the refractive index of which is close to the geometric mean value of the refractive indices of the two adjacent media. In that situation, two reflections of equal magnitude arise at the two interfaces, and these cancel each other by destructive interference.

The advanced ion-beam sputtering (IBS) thin-film coating facility of EKSMA Optics is ready to meet the most critical demands on laser optics. EKSMA Optics optical engineers can design and produce complex low loss and high LIDT anti-reflection coatings to suit your application. By employing IBS technology we can deposit highly reproducible dielectric thin film coatings with precisely controlled spectral parameters.

The pyramids in Egypt, the Acropolis and the Parthenon in Greece, the Roman aqueducts, Via Appia and the Colosseum, Teotihuacán, the Great Wall of China, the Brihadeeswarar Temple of Thanjavur, among many others, stand as a testament to the ingenuity and skill of ancient civil and military engineers. Other monuments, no longer standing, such as the Hanging Gardens of Babylon, and the Pharos of Alexandria were important engineering achievements of their time and were considered among the Seven Wonders of the Ancient World.

The earliest civil engineer known by name is Imhotep.[4] As one of the officials of the Pharaoh, Djosèr, he probably designed and supervised the construction of the Pyramid of Djoser (the Step Pyramid) at Saqqara in Egypt around 2630–2611 BC.[7] Ancient Greece developed machines in both civilian and military domains. The Antikythera mechanism, the first known mechanical computer,[8][9] and the mechanical inventions of Archimedes are examples of early mechanical engineering. Some of Archimedes’ inventions as well as the Antikythera mechanism required sophisticated knowledge of differential gearing or epicyclic gearing, two key principles in machine theory that helped design the gear trains of the Industrial Revolution, and are still widely used today in diverse fields such as robotics and automotive engineering.[10]

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Apart from the reflection properties, the optical damage threshold of anti-reflection coatings can be of interest, for example for use in components for Q-switched lasers. Depending on the material combination, an AR coating can have a higher or lower damage threshold than the substrate material.

The inventions of Thomas Newcomen and James Watt gave rise to modern mechanical engineering. The development of specialized machines and machine tools during the industrial revolution led to the rapid growth of mechanical engineering both in its birthplace Britain and abroad.[4]

John Smeaton was the first self-proclaimed civil engineer and is often regarded as the “father” of civil engineering. He was an English civil engineer responsible for the design of bridges, canals, harbours, and lighthouses. He was also a capable mechanical engineer and an eminent physicist. Smeaton designed the third Eddystone Lighthouse (1755–59) where he pioneered the use of ‘hydraulic lime‘ (a form of mortar which will set under water) and developed a technique involving dovetailed blocks of granite in the building of the lighthouse. His lighthouse remained in use until 1877 and was dismantled and partially rebuilt at Plymouth Hoe where it is known as Smeaton’s Tower. He is important in the history, rediscovery of, and development of modern cement, because he identified the compositional requirements needed to obtain “hydraulicity” in lime; work which led ultimately to the invention of Portland cement.

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The term engineering is derived from the word engineer, which itself dates back to 1390 when an engine’er (literally, one who operates an engine) referred to “a constructor of military engines.”[5] In this context, now obsolete, an “engine” referred to a military machine, i.e., a mechanical contraption used in war (for example, a catapult). Notable examples of the obsolete usage which have survived to the present day are military engineering corps, e.g., the U.S. Army Corps of Engineers.

LASEROPTIK offers a wide range of anti-reflection coatings for various types of optical elements in different wavelength regions from the mid IR to the UV. We can also supply coatings on special substrates and coatings for special applications.

Ecoptik can produce single-layer or multilayer anti-reflection coatings on various kinds of optical elements, using different materials. We achieve reflectivities <0.2% or even better at many wavelengths from 355 nm to 1550 nm, and <0.5% at 284 nm or 193 nm, for example.

For maximum transmission, Knight Optical offers a range of AR coatings to reduce surface reflections. Available as single layer MgF2 coatings, or multi-layer coatings, we can offer AR coatings centred to a specific wavelength or over a broadband wavelength range. With AR coatings from UV to IR, Knight Optical can help with your custom order.

With the rise of engineering as a profession in the 18th century, the term became more narrowly applied to fields in which mathematics and science were applied to these ends. Similarly, in addition to military and civil engineering, the fields then known as the mechanic arts became incorporated into engineering.

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UltraFast Innovations (UFI) offers broadband anti-reflection coatings suitable for ultrafast laser devices, with numerous options for different wavelength ranges and angles of incidence.

In most cases, AR coatings are used on optical interfaces with an area of at least a few millimeters squared. However, it is also possible to produce such coatings on the ends of optical fibers, sometimes even in jacketed and connectorized assemblies. There are various technical difficulties, e.g. related to outgasing of polymer jackets in a vacuum chamber and to the limited number of fiber ends which can be treated in one batch, but specialized sputtering processes have been developed which mitigate these problems. The coating performance can be as good as for normal bulk surfaces, at least for simple coating designs with only fewer layers.

engineering中文

The creative application of scientific principles to design or develop structures, machines, apparatus, or manufacturing processes, or works utilizing them singly or in combination; or to construct or operate the same with full cognizance of their design; or to forecast their behavior under specific operating conditions; all as respects an intended function, economics of operation and safety to life and property.[3][4]

For designing multilayer interference coatings, a flexible simulation and design software is indispensable. It must not only be able to calculate all relevant optical properties for a given design, but assist you in finding a suitable design for achieving given target properties. The RP Coating software is an ideal tool for such work, as it is particularly flexible. For example, you can define a figure of merit, formulating the optimization goal, of any conceivable kind.

An anti-reflection coating (AR coating) is a dielectric thin-film coating applied to an optical surface in order to reduce the reflectance (also often called reflectivity) of that surface due to Fresnel reflections – at least in a certain wavelength range. Examples of the application of such coatings are spectacles, optical systems like camera objectives, optical windows, displays and photovoltaic cells.

The United States census of 1850 listed the occupation of “engineer” for the first time with a count of 2,000.[13] There were fewer than 50 engineering graduates in the U.S. before 1865. In 1870 there were a dozen U.S. mechanical engineering graduates, with that number increasing to 43 per year in 1875. In 1890, there were 6,000 engineers in civil, mining, mechanical and electrical.[14]

The foundations of electrical engineering in the 1800s included the experiments of Alessandro Volta, Michael Faraday, Georg Ohm and others and the invention of the electric telegraph in 1816 and the electric motor in 1872. The theoretical work of James Maxwell (see: Maxwell’s equations) and Heinrich Hertz in the late 19th century gave rise to the field of electronics. The later inventions of the vacuum tube and the transistor further accelerated the development of electronics to such an extent that electrical and electronics engineers currently outnumber their colleagues of any other engineering specialty.[4] Chemical engineering developed in the late nineteenth century.[4] Industrial scale manufacturing demanded new materials and new processes and by 1880 the need for large scale production of chemicals was such that a new industry was created, dedicated to the development and large scale manufacturing of chemicals in new industrial plants.[4] The role of the chemical engineer was the design of these chemical plants and processes.[4]

Focuslight Technologies offers AR coatings from DUV (248 nm) to the infrared and a great selection of coating tests and analysis, including spectrometer and LIDT test. Focuslight can coat substrates up to 140 mm × 140 mm at the moment. Capacity available! Customization acceptable!

Perkins Precision Developments (PPD) manufactures custom IBS coatings, including anti-reflection coatings. PPD utilizes Ion Beam Sputtering coating technology because it is ideal for complex spectral designs, high power Nd:YAG and fiber lasers and applications where it is critical to minimize losses from absorption and/or scatter. IBS thin films have densely packed micro-structures resulting in stable, easy to clean optics that are insensitive to environmental changes such as heat, humidity and pressure. Our AR coatings exceed damage thresholds of 25 J/cm2 or sometimes even >60 J/cm2 at 1064 nm.

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With absorption being at low level (<1 ppm per coated surface at 1064 nm) AR coated windows and AR coated lenses feature enhanced lifetimes.

Even for given coating materials, the damage threshold can vary considerably depending on the fabrication technique. Ion beam sputtering is known to allow for relatively high damage thresholds.

Ancient Chinese, Greek, Roman and Hungarian armies employed military machines and inventions such as artillery which was developed by the Greeks around the 4th century B.C.,[11] the trireme, the ballista and the catapult. In the Middle Ages, the trebuchet was developed.

Engineering is the creative application of science, mathematical methods, and empirical evidence to the innovation, design, construction, and maintenance of structures, machines, materials, devices, systems, processes, and organizations. The discipline of engineering encompasses a broad range of more specialized fields of engineering, each with a more specific emphasis on particular areas of applied mathematics, applied science, and types of application. See glossary of engineering.

OPTOMAN offers high-performance sputtered anti-reflective coatings with reflectance per surface down to R < 0.01%. IBS coatings are optimized for temperature and humidity-independent performance, high damage threshold (> 168 J/cm2 @ 1064 nm, 9.8 ns, 100 Hz, 223 μm). Single wavelength, multiwavelength, or broadband coatings can be designed for the spectral range from 200 nm to 5000 nm.

Analytical design rules exist for simple types of anti-reflection coatings with very few thin-film layers. For more sophisticated designs, numerical optimization algorithms similar to those described in the article on dielectric mirrors can be used. The resulting designs are normally not easily understood, as the anti-reflection properties result from a complicated interference of the reflections from various interfaces.

An unusual type of anti-reflection coating is one consisting of a very thin layer of some strongly absorbing material. The thickness can be only some tens of nanometers, i.e., far less than usually required for lossless AR coatings, as strong imaginary components of the propagation constant of such media lead to substantial phase changes. The incident light is largely absorbed by such structures, rather than transmitted. Such anti-reflection structures are called photonic metamaterials due to the combination of sub-wavelength structures, although simple interference phenomena are sufficient for understanding their characteristics [13].

The first PhD in engineering (technically, applied science and engineering) awarded in the United States went to Josiah Willard Gibbs at Yale University in 1863; it was also the second PhD awarded in science in the U.S.[17]

The word “engine” itself is of even older origin, ultimately deriving from the Latin ingenium (c. 1250), meaning “innate quality, especially mental power, hence a clever invention.”[6]