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Campanile Probe
In near-field scanning optical microscopy the campanile probe is a tapered optical probe with a shape of a campanile (a square pyramid). It is made of an optically transparent dielectric, typically silica, and its two facets are coated with a metal, typically gold. At the probe tip, the metal-coated facets are separated by a gap of a few tens of nanometers, which determines the spatial resolution of the probe. Such a probe design allows collecting optical signals, usually photoluminescence (PL) or Raman scattering, with a subwavelength resolution, breaking the diffraction limit. The campanile probe is attached to an optical fiber, which both provides a laser excitation of the studied sample and collects the measured signal. The probe is rastered over the sample with a standard scanning probe microscopy scanner, keeping the distance to the sample surface at a few nanometers. Contrary to the traditional (circular) near-field probes, the campanile probe has no cut-off frequency and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Campanile Probe2
A bell tower is a tower that contains one or more bells, or that is designed to hold bells even if it has none. Such a tower commonly serves as part of a Christian church (building), church, and will contain church bells, but there are also many secular bell towers, often part of a municipal building, an educational establishment, or a tower built specifically to house a carillon. Church bell towers often incorporate clocks, and secular towers usually do, as a public service. The term campanile (, also , ), deriving from the Italian ''campanile'', which in turn derives from ''campana'', meaning "bell", is synonymous with ''bell tower''; though in English usage campanile tends to be used to refer to a free standing bell tower. A bell tower may also in some traditions be called a Belfry (architecture), belfry, though this term may also refer specifically to the substructure that houses the bells and the ringers rather than the complete tower. The tallest free-standing bell tower i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gold
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile metal in a pure form. Chemically, gold is a transition metal and a group 11 element. It is one of the least reactive chemical elements and is solid under standard conditions. Gold often occurs in free elemental ( native state), as nuggets or grains, in rocks, veins, and alluvial deposits. It occurs in a solid solution series with the native element silver (as electrum), naturally alloyed with other metals like copper and palladium, and mineral inclusions such as within pyrite. Less commonly, it occurs in minerals as gold compounds, often with tellurium (gold tellurides). Gold is resistant to most acids, though it does dissolve in aqua regia (a mixture of nitric acid and hydrochloric acid), forming a soluble tetrachloroaurate anion. Gold is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focused Ion Beam
Focused ion beam, also known as FIB, is a technique used particularly in the semiconductor industry, materials science and increasingly in the biological field for site-specific analysis, deposition, and ablation of materials. A FIB setup is a scientific instrument that resembles a scanning electron microscope (SEM). However, while the SEM uses a focused beam of electrons to image the sample in the chamber, a FIB setup uses a focused beam of ions instead. FIB can also be incorporated in a system with both electron and ion beam columns, allowing the same feature to be investigated using either of the beams. FIB should not be confused with using a beam of focused ions for direct write lithography (such as in proton beam writing). These are generally quite different systems where the material is modified by other mechanisms. Ion beam source Most widespread instruments are using liquid metal ion sources (LMIS), especially gallium ion sources. Ion sources based on elemental gold an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrofluoric Acid
Hydrofluoric acid is a Solution (chemistry), solution of hydrogen fluoride (HF) in water. Solutions of HF are colourless, acidic and highly Corrosive substance, corrosive. It is used to make most fluorine-containing compounds; examples include the commonly used pharmaceutical antidepressant medication fluoxetine (Prozac) and the material polytetrafluoroethylene, PTFE (Teflon). Elemental fluorine is produced from it. It is commonly used to Etching (microfabrication), etch glass and silicon wafers. Uses Production of organofluorine compounds The principal use of hydrofluoric acid is in organofluorine chemistry. Many organofluorine compounds are prepared using HF as the fluorine source, including Polytetrafluoroethylene, Teflon, fluoropolymers, fluorocarbons, and refrigeration, refrigerants such as freon. Many pharmaceuticals contain fluorine. Production of inorganic fluorides Most high-volume inorganic fluoride compounds are prepared from hydrofluoric acid. Foremost are Na3AlF6 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scanning Probe Microscopy
Scan may refer to: Acronyms * Schedules for Clinical Assessment in Neuropsychiatry (SCAN), a psychiatric diagnostic tool developed by WHO * Shared Check Authorization Network (SCAN), a database of bad check writers and collection agency for bad checks * Space Communications and Navigation Program (SCaN) * Social Cognitive and Affective Neuroscience (journal) * Scientific content analysis (SCAN), also known as statement analysis Businesses * Scan Furniture, Washington, D.C., US chain * SCAN Health Plan, not-for-profit health care company based in Long Beach, California * Scan AB or Scan Foods UK Ltd, the Swedish and UK subsidiaries of the Finnish HKScan Oyj * Seattle Community Access Network, Seattle, Washington, US TV channel * Scan (company), a software company based in Provo, Utah, US Electronics or computer related * 3D scanning * Counter-scanning, in physical micro and nanotopography measuring instruments like scanning probe microscope * Elevator algorithm (also SC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffraction-limited System
The resolution of an optical imaging system a microscope, telescope, or camera can be limited by factors such as imperfections in the lenses or misalignment. However, there is a principal limit to the resolution of any optical system, due to the physics of diffraction. An optical system with resolution performance at the instrument's theoretical limit is said to be diffraction-limited. The diffraction-limited angular resolution of a telescopic instrument is inversely proportional to the wavelength of the light being observed, and proportional to the diameter of its objective's entrance aperture. For telescopes with circular apertures, the size of the smallest feature in an image that is diffraction limited is the size of the Airy disk. As one decreases the size of the aperture of a telescopic lens, diffraction proportionately increases. At small apertures, such as f/22, most modern lenses are limited only by diffraction and not by aberrations or other imperfections in the cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raman Scattering
Raman scattering or the Raman effect () is the inelastic scattering of photons by matter, meaning that there is both an exchange of energy and a change in the light's direction. Typically this effect involves vibrational energy being gained by a molecule as incident photons from a visible laser are shifted to lower energy. This is called normal Stokes Raman scattering. The effect is exploited by chemists and physicists to gain information about materials for a variety of purposes by performing various forms of Raman spectroscopy. Many other variants of Raman spectroscopy allow rotational energy to be examined (if gas samples are used) and electronic energy levels may be examined if an X-ray source is used in addition to other possibilities. More complex techniques involving pulsed lasers, multiple laser beams and so on are known. Light has a certain probability of being scattered by a material. When photons are scattered, most of them are elastically scattered (Rayleigh scatt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoluminescence
Photoluminescence (abbreviated as PL) is light emission from any form of matter after the absorption of photons (electromagnetic radiation). It is one of many forms of luminescence (light emission) and is initiated by photoexcitation (i.e. photons that excite electrons to a higher energy level in an atom), hence the prefix ''photo-''. Following excitation, various relaxation processes typically occur in which other photons are re-radiated. Time periods between absorption and emission may vary: ranging from short femtosecond-regime for emission involving free-carrier plasma in inorganic semiconductorsHayes, G.R.; Deveaud, B. (2002). "Is Luminescence from Quantum Wells Due to Excitons?". ''Physica Status Solidi A'' 190 (3): 637–640doi:10.1002/1521-396X(200204)190:33.0.CO;2-7/ref> up to milliseconds for phosphoresence processes in molecular systems; and under special circumstances delay of emission may even span to minutes or hours. Observation of photoluminescence at a certain ene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and most abundant families of materials, existing as a compound of several minerals and as a synthetic product. Notable examples include fused quartz, fumed silica, silica gel, opal and aerogels. It is used in structural materials, microelectronics (as an Insulator (electricity), electrical insulator), and as components in the food and pharmaceutical industries. Structure In the majority of silicates, the silicon atom shows tetrahedral coordination geometry, tetrahedral coordination, with four oxygen atoms surrounding a central Si atomsee 3-D Unit Cell. Thus, SiO2 forms 3-dimensional network solids in which each silicon atom is covalently bonded in a tetrahedral manner to 4 oxygen atoms. In contrast, CO2 is a linear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Campanile Probe3
A bell tower is a tower that contains one or more bells, or that is designed to hold bells even if it has none. Such a tower commonly serves as part of a Christian church, and will contain church bells, but there are also many secular bell towers, often part of a municipal building, an educational establishment, or a tower built specifically to house a carillon. Church bell towers often incorporate clocks, and secular towers usually do, as a public service. The term campanile (, also , ), deriving from the Italian ''campanile'', which in turn derives from ''campana'', meaning "bell", is synonymous with ''bell tower''; though in English usage campanile tends to be used to refer to a free standing bell tower. A bell tower may also in some traditions be called a belfry, though this term may also refer specifically to the substructure that houses the bells and the ringers rather than the complete tower. The tallest free-standing bell tower in the world, high, is the Mortegliano ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dielectric
In electromagnetism, a dielectric (or dielectric medium) is an electrical insulator that can be polarised by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the material as they do in an electrical conductor, because they have no loosely bound, or free, electrons that may drift through the material, but instead they shift, only slightly, from their average equilibrium positions, causing dielectric polarisation. Because of dielectric polarisation, positive charges are displaced in the direction of the field and negative charges shift in the direction opposite to the field (for example, if the field is moving parallel to the positive ''x'' axis, the negative charges will shift in the negative ''x'' direction). This creates an internal electric field that reduces the overall field within the dielectric itself. If a dielectric is composed of weakly bonded molecules, those molecules not only become polaris ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Square Pyramid
In geometry, a square pyramid is a pyramid having a square base. If the apex is perpendicularly above the center of the square, it is a right square pyramid, and has symmetry. If all edge lengths are equal, it is an equilateral square pyramid, the Johnson solid General square pyramid A possibly oblique square pyramid with base length ''l'' and perpendicular height ''h'' has volume: :V=\frac l^2 h. Right square pyramid In a right square pyramid, all the lateral edges have the same length, and the sides other than the base are congruent isosceles triangles. A right square pyramid with base length ''l'' and height ''h'' has surface area and volume: :A=l^2+l\sqrt, :V=\frac l^2 h. The lateral edge length is: :\sqrt; the slant height is: :\sqrt. The dihedral angles are: :*between the base and a side: :::\arctan \left(\right); :*between two sides: :::\arccos \left(\right). Equilateral square pyramid, Johnson solid J1 If all edges have the same length, then the sides are e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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