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Digital Planar Holography
Digital planar holography (DPH) is a method for designing and fabricating miniature components for integrated optics. It was invented by Vladimir Yankov and first published in 2003. The essence of the DPH technology is embedding computer designed digital holograms inside a planar waveguide. Light propagates through the plane of the hologram instead of perpendicularly, allowing for a long interaction path. Benefits of a long interaction path have long been used by volume or thick holograms. Planar configuration of the hologram provider for easier access to the embedded diagram aiding in its manufacture. Light can be confined in waveguides by a refractive index gradient. Light propagates in a core layer, surrounded by a cladding layer(s), which should be selected such that the core refractive index ''N''core is greater than that of cladding ''N''clad: ''N''core> ''N''clad. Cylindrical waveguides (optical fibers) allow for one-dimensional light propagation along the axis. Plana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integrated Optics
A photonic integrated circuit (PIC) or integrated optical circuit is a microchip containing two or more photonic components which form a functioning circuit. This technology detects, generates, transports, and processes light. Photonic integrated circuits utilize photons (or particles of light) as opposed to electrons that are utilized by electronic integrated circuits. The major difference between the two is that a photonic integrated circuit provides functions for information signals imposed on optical wavelengths typically in the visible spectrum or near infrared (850–1650 nm). The most commercially utilized material platform for photonic integrated circuits is indium phosphide (InP), which allows for the integration of various optically active and passive functions on the same chip. Initial examples of photonic integrated circuits were simple 2-section distributed Bragg reflector (DBR) lasers, consisting of two independently controlled device sections – a gain section ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Holography
Digital holography refers to the acquisition and processing of holograms with a digital sensor array, typically a CCD camera or a similar device. Image rendering, or reconstruction of object ''data'' is performed numerically from digitized interferograms. Digital holography offers a means of measuring optical phase data and typically delivers three-dimensional surface or optical thickness images. Several recording and processing schemes have been developed to assess optical wave characteristics such as amplitude, phase, and polarization state, which make digital holography a very powerful method for metrology applications . Digital recording and processing of holograms Off-axis configuration In the off-axis configuration, a small angle between the reference and the object beams is used to prevent overlapping of the cross-beating contributions between the object and reference optical fields with the self-beating contributions of these fields. These discoveries were made by Emmett Le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waveguide (optics)
An optical waveguide is a physical structure that guides electromagnetic waves in the optical spectrum. Common types of optical waveguides include optical fiber waveguides, transparent dielectric waveguides made of plastic and glass, liquid light guides, and liquid waveguides. Optical waveguides are used as components in integrated optical circuits or as the transmission medium in local and long-haul optical communication systems. Optical waveguides can be classified according to their geometry (planar, strip, or fiber waveguides), mode structure (single-mode optical fiber, single-mode, multi-mode optical fiber, multi-mode), refractive index distribution (step or gradient index), and material (glass, polymer, semiconductor). Total internal reflection The basic principles behind optical waveguides can be described using the concepts of geometrical optics, geometrical or ray optics, as illustrated in the diagram. Light passing into a medium with higher refractive index bends towa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volume Hologram
Volume holograms are holograms where the thickness of the recording material is much larger than the light wavelength used for recording. In this case diffraction of light from the hologram is possible only as Bragg diffraction, i.e., the light has to have the right wavelength (color) and the wave must have the right shape (beam direction, wavefront profile). Volume holograms are also called ''thick holograms'' or ''Bragg holograms''. Theory Volume holograms were first treated by Herwig Kogelnik, H. Kogelnik in 1969 by the so-called "coupled-wave theory". For volume ''phase'' holograms it is possible to diffract 100% of the incoming reference light into the signal wave, i.e., full diffraction of light can be achieved. Volume ''absorption'' holograms show much lower efficiencies. H. Kogelnik provides analytical solutions for transmission as well as for reflection conditions. A good text-book description of the theory of volume holograms can be found in a book from J. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Fiber
An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a 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 bandwidths (data transfer rates) than electrical cables. Fibers are used instead of metal wires because signals travel along them with less loss; in addition, fibers are immune to electromagnetic interference, a problem from which metal wires suffer. Fibers are also used for 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. Specially designed fibers are also used for a variety of other applications, some of them being fiber optic sensors and fiber lasers. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waveguide (optics)
An optical waveguide is a physical structure that guides electromagnetic waves in the optical spectrum. Common types of optical waveguides include optical fiber waveguides, transparent dielectric waveguides made of plastic and glass, liquid light guides, and liquid waveguides. Optical waveguides are used as components in integrated optical circuits or as the transmission medium in local and long-haul optical communication systems. Optical waveguides can be classified according to their geometry (planar, strip, or fiber waveguides), mode structure (single-mode optical fiber, single-mode, multi-mode optical fiber, multi-mode), refractive index distribution (step or gradient index), and material (glass, polymer, semiconductor). Total internal reflection The basic principles behind optical waveguides can be described using the concepts of geometrical optics, geometrical or ray optics, as illustrated in the diagram. Light passing into a medium with higher refractive index bends towa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanoimprint Lithography
Nanoimprint lithography (NIL) is a method of fabricating nanometer scale patterns. It is a simple nanolithography process with low cost, high throughput and high resolution. It creates patterns by mechanical deformation of imprint resist and subsequent processes. The imprint resist is typically a monomer or polymer formulation that is cured by heat or UV light during the imprinting. Adhesion between the resist and the template is controlled to allow proper release. History The term "nanoimprint lithography" was coined in the scientific literature in 1996, when Prof. Stephen Chou and his students published a report in ''Science'', although hot embossing (now taken as a synonym of NIL) of thermoplastics had been appearing in the patent literature for a few years already. Soon after the ''Science'' paper, many researchers developed different variations and implementations. At this point, nanoimprint lithography has been added to the International Technology Roadmap for Semiconductor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photonic Integrated Circuits
A photonic integrated circuit (PIC) or integrated optical circuit is a microchip containing two or more photonic components which form a functioning circuit. This technology detects, generates, transports, and processes light. Photonic integrated circuits utilize photons (or particles of light) as opposed to electrons that are utilized by electronic integrated circuits. The major difference between the two is that a photonic integrated circuit provides functions for information signals imposed on optical wavelengths typically in the visible spectrum or near infrared (850–1650 nm). The most commercially utilized material platform for photonic integrated circuits is indium phosphide (InP), which allows for the integration of various optically active and passive functions on the same chip. Initial examples of photonic integrated circuits were simple 2-section distributed Bragg reflector (DBR) lasers, consisting of two independently controlled device sections – a gain section ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planar Lightwave Circuit Interferometer
An interferometer is an optical measuring device using the principle of light waves canceling and reinforcing each other. Interferometers are typically used to accurately measure distances. Planar lightwave circuits are either optical integrated circuits (ICs) or optical circuit boards made using the same manufacturing techniques as their electronic counterparts, using optical waveguides to route photons the same way that metal traces are used to route electrons in electronic ICs and circuit boards. A planar lightwave circuit interferometer (PLCI) is a planar lightwave circuit configured as an interferometer. PLCIs can take on any form which is rigidly printable, e.g. Mach-Zehnder, Michelson, Young's interferometer, etc. PLCIs are often found in products that are mass-produced, such as multiplexers/demultiplexers [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DPH Devices
DPH may refer to: Arts *Designated hitter in baseball ("designated pinch hitter") *Digital planar holography Government and law *Georgia Department of Public Health *Los Angeles County Department of Public Health *''Daň z přidané hodnoty'', the Value Added Tax in the Czech Republic *''Daň z pridanej hodnoty'', the Value Added Tax in Slovakia Health and medicine *Diphenylhydantoin, commonly used antiepileptic; see Phenytoin *Diphenhydramine, a first generation antihistamine mainly used to treat allergies * Doctor of Public Health Science and engineering *Diamond Pyramid Hardness; see Vickers hardness test * Daytime parahypnagogia * Diphenylhexatriene, a fluorescent hydrocarbon used in the study of cell membranes. *Discrete phase-type distribution in Markov chain theory *''Days post hatching Hatching (french: hachure) is an artistic technique used to create tonal or shading effects by drawing (or painting or scribing) closely spaced parallel lines. (It is also used in mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
