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Fabry–Pérot Interferometer
In optics, a Fabry–Pérot interferometer (FPI) or etalon is an optical cavity made from two parallel reflecting surfaces (i.e.: thin mirrors). Optical waves can pass through the optical cavity only when they are in resonance with it. It is named after Charles Fabry and Alfred Perot, who developed the instrument in 1899. ''Etalon'' is from the French ''étalon'', meaning "measuring gauge" or "standard". Etalons are widely used in telecommunications, lasers and spectroscopy to control and measure the wavelengths of light. Recent advances in fabrication technique allow the creation of very precise tunable Fabry–Pérot interferometers. The device is technically an interferometer when the distance between the two surfaces (and with it the resonance length) can be changed, and an etalon when the distance is fixed (however, the two terms are often used interchangeably). Basic description The heart of the Fabry–Pérot interferometer is a pair of partially reflective glass o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fabry Perot Etalon Rings Fringes
Fabry or Fábry is a surname. Notable people with the surname include: * Branislav Fábry (born 1985), Slovak ice hockey player *Charles Fabry, French physicist, co-inventor of the Fabry-Pérot etalon * Jean Fabry (1876-1968), French politician * Johannes Fabry, German dermatologist who provided the first description of Anderson-Fabry disease * Joseph Fabry, author and editor of logotherapy * Pál Fábry, Hungarian politician and journalist *Sándor Fábry, Hungarian showman Fictional characters: *Fabry, Chief Engineer at Rossum's Universal Robots in the play R.U.R. See also *Fabry disease - a genetic disorder that can affect the kidneys, heart, and skin caused by a deficiency in the enzyme alpha-galactosidase A * Fabbri * Fabre * Fabri Fabri is a surname. Notable people with the surname include: * Anna Fabri (f. 1496), Swedish publisher and printer * Annibale Pio Fabri (1697–1760), Italian singer and composer * Emanuel Fabri (born 1952), Maltese footballer * Ernst Fabri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Flat
An optical flat is an optical-grade piece of glass lapped and polished to be extremely flat on one or both sides, usually within a few tens of nanometres (billionths of a metre). They are used with a monochromatic light to determine the flatness (surface accuracy) of other surfaces, whether optical, metallic, ceramic, or otherwise, by interference. When an optical flat is placed on another surface and illuminated, the light waves reflect off both the bottom surface of the flat and the surface it is resting on. This causes a phenomenon similar to thin-film interference. The reflected waves interfere, creating a pattern of interference fringes visible as light and dark bands. The spacing between the fringes is smaller where the gap is changing more rapidly, indicating a departure from flatness in one of the two surfaces. This is comparable to the contour lines one would find on a map. A flat surface is indicated by a pattern of straight, parallel fringes with equal spacing, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Filter
An optical filter is a device that selectively transmits light of different wavelengths, usually implemented as a glass plane or plastic device in the optical path, which are either dyed in the bulk or have interference coatings. The optical properties of filters are completely described by their frequency response, which specifies how the magnitude and phase of each frequency component of an incoming signal is modified by the filter. Filters mostly belong to one of two categories. The simplest, physically, is the absorptive filter; then there are interference or dichroic filters. Many optical filters are used for optical imaging and are manufactured to be transparent; some used for light sources can be translucent. Optical filters selectively transmit light in a particular range of wavelengths, that is, colours, while absorbing the remainder. They can usually pass long wavelengths only (longpass), short wavelengths only (shortpass), or a band of wavelengths, block ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuum Deposition
Vacuum deposition is a group of processes used to deposit layers of material atom-by-atom or molecule-by-molecule on a solid surface. These processes operate at pressures well below atmospheric pressure (i.e., vacuum). The deposited layers can range from a thickness of one atom up to millimeters, forming freestanding structures. Multiple layers of different materials can be used, for example to form optical coatings. The process can be qualified based on the vapor source; physical vapor deposition uses a liquid or solid source and chemical vapor deposition uses a chemical vapor. Description The vacuum environment may serve one or more purposes: * reducing the particle density so that the mean free path for collision is long * reducing the particle density of undesirable atoms and molecules (contaminants) * providing a low pressure plasma environment * providing a means for controlling gas and vapor composition * providing a means for mass flow control into the processing ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichroic Filter
A dichroic filter, thin-film filter, or interference filter is a color filter used to selectively pass light of a small range of colors while reflecting other colors. By comparison, dichroic mirrors and dichroic reflectors tend to be characterized by the colors of light that they reflect, rather than the colors they pass. Dichroic filters can filter light from a white light source to produce light that is perceived by humans to be highly saturated in color. Such filters are popular in architectural and theatrical applications. Dichroic reflectors known as cold mirrors are commonly used behind a light source to reflect visible light forward while allowing the invisible infrared light to pass out of the rear of the fixture. Such an arrangement allows intense illumination with less heating of the illuminated object. Many quartz-halogen lamps have an integrated dichroic reflector for this purpose, being originally designed for use in slide projectors to avoid melting the sl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diamond
Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, but diamond is metastable and converts to it at a negligible rate under those conditions. Diamond has the highest hardness and thermal conductivity of any natural material, properties that are used in major industrial applications such as cutting and polishing tools. They are also the reason that diamond anvil cells can subject materials to pressures found deep in the Earth. Because the arrangement of atoms in diamond is extremely rigid, few types of impurity can contaminate it (two exceptions are boron and nitrogen). Small numbers of defects or impurities (about one per million of lattice atoms) color diamond blue (boron), yellow (nitrogen), brown (defects), green (radiation exposure), purple, pink, orange, or red. Diamond also has a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fused Silica
Fused quartz, fused silica or quartz glass is a glass consisting of almost pure silica (silicon dioxide, SiO2) in amorphous (non-crystalline) form. This differs from all other commercial glasses in which other ingredients are added which change the glasses' optical and physical properties, such as lowering the melt temperature. Fused quartz, therefore, has high working and melting temperatures, making it less desirable for most common applications. The terms fused quartz and fused silica are used interchangeably, but can refer to different manufacturing techniques, as noted below, resulting in different trace impurities. However fused quartz, being in the glassy state, has quite different physical properties compared to crystalline quartz. Due to its physical properties it finds specialty uses in semiconductor fabrication and laboratory equipment, for instance. Compared to other common glasses, the optical transmission of pure silica extends well into the ultraviolet and infra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Add-drop Multiplexer
An add-drop multiplexer (ADM) is an important element of an optical fiber network. A multiplexer combines, or multiplexes, several lower- bandwidth streams of data into a single beam of light. An ''add-drop'' multiplexer also has the capability to ''add'' one or more lower-bandwidth signals to an existing high-bandwidth data stream, and at the same time can extract or ''drop'' other low-bandwidth signals, removing them from the stream and redirecting them to some other network path. This is used as a local "on-ramp" and "off-ramp" to the high-speed network. ADMs can be used both in long-haul core networks and in shorter-distance "metro" networks, although the former are much more expensive due to the difficulty of scaling the technology to the high data rates and dense wavelength division multiplexing (DWDM) used for long-haul communications. The main optical filtering technology used in add-drop multiplexers is the Fabry–Pérot etalon. Newer "multi-service SONET/SDH" (al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wavelength Division Multiplexing
In fiber-optic communications, wavelength-division multiplexing (WDM) is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths (i.e., colors) of laser light. This technique enables bidirectional communications over a single strand of fiber, also called wavelength-division duplexing, as well as multiplication of capacity. The term WDM is commonly applied to an optical carrier, which is typically described by its wavelength, whereas frequency-division multiplexing typically applies to a radio carrier which is more often described by frequency. This is purely conventional because wavelength and frequency communicate the same information. Specifically, frequency (in Hertz, which is cycles per second) multiplied by wavelength (the physical length of one cycle) equals the velocity of the carrier wave. In a vacuum, this is the speed of light, usually denoted by the lowercase letter, c. In glass fiber, it is sub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dispositif Fabry-Perot
Dispositif or dispositive is a term used by the French intellectual Michel Foucault, generally to refer to the various institutional, physical, and administrative mechanisms and knowledge structures which enhance and maintain the exercise of power within the social body. The links between these elements are said to be heterogeneous since knowledge, practices, techniques, and institutions are established and reestablished in every age. It is through these links that power relations are structured. Translation Dispositif is translated variously, even in the same book, as 'device', 'machinery', 'apparatus', 'construction', and 'deployment'. Definition Foucault uses the term in his 1977 "The Confession of the Flesh" interview, where he answers the question, "What is the meaning or methodological function for you of this term, apparatus (dispositif)?" as follows: :''"What I'm trying to pick out with this term is, firstly, a thoroughly heterogeneous ensemble consisting of discourses, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monochromatic Light
{{Short description, Electromagnetic radiation with a single constant frequency In physics, monochromatic radiation is electromagnetic radiation with a single constant frequency. When that frequency is part of the visible spectrum (or near it) the term monochromatic light is often used. Monochromatic light is perceived by the human eye as a spectral color. When monochromatic radiation propagates through vacuum or a homogeneous transparent medium, it has a single constant wavelength. Practical monochromaticity No radiation can be totally monochromatic, since that would require a wave of infinite duration as a consequence of the Fourier transform's localization property (cf. spectral coherence). In practice, "monochromatic" radiation — even from lasers or spectral lines — always consists of components with a range of frequencies of non-zero width. Generation Monochromatic radiation can be produced by a number of methods. Isaac Newton observed that a beam of light from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Q Factor
In physics and engineering, the quality factor or ''Q'' factor is a dimensionless parameter that describes how underdamped an oscillator or resonator is. It is defined as the ratio of the initial energy stored in the resonator to the energy lost in one radian of the cycle of oscillation. Q factor is alternatively defined as the ratio of a resonator's centre frequency to its bandwidth when subject to an oscillating driving force. These two definitions give numerically similar, but not identical, results. Higher ''Q'' indicates a lower rate of energy loss and the oscillations die out more slowly. A pendulum suspended from a high-quality bearing, oscillating in air, has a high ''Q'', while a pendulum immersed in oil has a low one. Resonators with high quality factors have low damping, so that they ring or vibrate longer. Explanation The Q factor is a parameter that describes the resonance behavior of an underdamped harmonic oscillator (resonator). Sinusoidally driven reson ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
