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Optical Frequency Multiplier
An optical frequency multiplier is a nonlinear optical device in which photons interacting with a nonlinear material are effectively "combined" to form new photons with greater energy, and thus higher frequency (and shorter wavelength). Two types of devices are currently common: ''frequency doublers,'' often based on lithium niobate (LN), lithium tantalate (LT), potassium titanyl phosphate (KTP) or lithium triborate (LBO), and ''frequency triplers'' typically made of potassium dihydrogen phosphate (KDP). Both are widely used in optical experiments that use lasers as a light source. Harmonic generation There are two processes that are commonly used to achieve the conversion: second-harmonic generation (''SHG'', also called frequency doubling), or sum-frequency generation which sums two non-similar frequencies. Direct third-harmonic generation (''THG'', also called frequency tripling) also exists and can be used to detect an interface between materials of different excitability. Fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonlinear Optics
Nonlinear optics (NLO) is the branch of optics that describes the behaviour of light in ''nonlinear media'', that is, media in which the polarization density P responds non-linearly to the electric field E of the light. The non-linearity is typically observed only at very high light intensities (when the electric field of the light is >108 V/m and thus comparable to the atomic electric field of ~1011 V/m) such as those provided by lasers. Above the Schwinger limit, the vacuum itself is expected to become nonlinear. In nonlinear optics, the superposition principle no longer holds. History The first nonlinear optical effect to be predicted was two-photon absorption, by Maria Goeppert Mayer for her PhD in 1931, but it remained an unexplored theoretical curiosity until 1961 and the almost simultaneous observation of two-photon absorption at Bell Labs and the discovery of second-harmonic generation by Peter Franken ''et al.'' at University of Michigan, both shortly after the constru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shiva Laser
The Shiva laser was a powerful 20-beam infrared neodymium glass (silica glass) laser built at Lawrence Livermore National Laboratory in 1977 for the study of inertial confinement fusion (ICF) and long-scale-length laser-plasma interactions. Presumably, the device was named after the multi-armed form of the Hindu god Shiva, due to the laser's multi-beamed structure. Shiva was instrumental in demonstrating a particular problem in compressing targets with lasers, leading to a major new device being constructed to address these problems, the Nova laser. Background The basic idea of any ICF device is to rapidly heat the outer layers of a "target", normally a small plastic sphere containing a few milligrams of fusion fuel, typically a mix of deuterium and tritium. The heat burns the plastic into a plasma, which explodes off the surface. Due to Newton's Third Law, the remaining portion of the target is driven inwards, eventually collapsing into a small point of very high density. The ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Devices
An optical instrument (or "optic" for short) is a device that processes light waves (or photons), either to enhance an image for viewing or to analyze and determine their characteristic properties. Common examples include periscopes, microscopes, telescopes, and cameras. Image enhancement The first optical instruments were telescopes used for magnification of distant images, and microscopes used for magnifying very tiny images. Since the days of Galileo and Van Leeuwenhoek, these instruments have been greatly improved and extended into other portions of the electromagnetic spectrum. The binocular device is a generally compact instrument for both eyes designed for mobile use. A camera could be considered a type of optical instrument, with the pinhole camera and camera obscura being very simple examples of such devices. Analysis Another class of optical instrument is used to analyze the properties of light or optical materials. They include: * Interferometer for measuring the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Second-harmonic Generation
Second-harmonic generation (SHG, also called frequency doubling) is a nonlinear optical process in which two photons with the same frequency interact with a nonlinear material, are "combined", and generate a new photon with twice the energy of the initial photons (equivalently, twice the frequency and half the wavelength), that conserves the coherence of the excitation. It is a special case of sum-frequency generation (2 photons), and more generally of harmonic generation. The second-order nonlinear susceptibility of a medium characterizes its tendency to cause SHG. Second-harmonic generation, like other even-order nonlinear optical phenomena, is not allowed in media with inversion symmetry (in the leading electric dipole contribution). However, effects such as the Bloch–Siegert shift (oscillation), found when two-level systems are driven at Rabi frequencies comparable to their transition frequencies, will give rise to second harmonic generation in centro-symmetric systems. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Ignition Facility
The National Ignition Facility (NIF) is a laser-based inertial confinement fusion (ICF) research device, located at Lawrence Livermore National Laboratory in Livermore, California, United States. NIF's mission is to achieve fusion ignition with high energy gain. It achieved the first scientific breakeven controlled fusion experiment on December 5, 2022, with an energy gain factor of 1.5. It supports nuclear weapon maintenance and design by studying the behavior of matter under the conditions found within nuclear explosions. NIF is the largest and most powerful ICF device built to date. The basic ICF concept is to squeeze a small amount of fuel to reach pressure and temperature necessary for fusion. NIF hosts the world's most energetic laser. The laser heats the outer layer of a small sphere. The energy is so intense that it causes the sphere to implode, squeezing the fuel inside. The implosion reaches a peak speed of , raising the fuel density from about that of water to abo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionization, ionize atoms, it can cause chemical reactions and causes many substances to glow or fluorescence, fluoresce. Consequently, the chemical and biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules. Short-wave ultraviolet light damages DNA and sterilizes surf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monopotassium Phosphate
Monopotassium phosphate (MKP) (also, potassium dihydrogenphosphate, KDP, or monobasic potassium phosphate) is the inorganic compound with the formula KH2PO4. Together with dipotassium phosphate (K2HPO4.(H2O)x) it is often used as a fertilizer, food additive, and buffering agent. The salt often cocrystallizes with the dipotassium salt as well as with phosphoric acid. Single crystals are paraelectric at room temperature. At temperatures below , they become ferroelectric. Structure Monopotassium phosphate can exist in several Polymorphism (materials science), polymorphs. At room temperature it forms paraelectric crystals with tetragonal symmetry. Upon cooling to it transforms to a ferroelectric phase of orthorhombic symmetry, and the transition temperature shifts up to when hydrogen is replaced by deuterium. Heating to changes its structure to monoclinic. When heated further, MKP decomposes, by loss of water, to potassium metaphosphate, , at . Manufacturing Monopotassium phos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Novette Laser
Novette was a two beam neodymium glass (phosphate glass) testbed laser built at Lawrence Livermore National Laboratory in about 15 months throughout 1981 and 1982 and was completed in January 1983. Novette was made using recycled parts from the dismantled Shiva and Argus lasers and borrowed parts from the future Nova laser. Its main intended purpose was to validate the proposed design and expected performance of the then planned Nova laser. In addition to being used for the further study of enhanced laser to target plasma energy coupling utilizing frequency tripled light and examining its benefits with respect to inertial confinement fusion, Novette was also used in the world's first laboratory demonstration of an x-ray laser in 1984. See also * List of laser articles * List of laser types This is a list of laser types, their operational wavelengths, and their applications. Thousands of kinds of laser are known, but most of them are used only for specialized research. Overview ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OMEGA Laser
The Laboratory for Laser Energetics (LLE) is a scientific research facility which is part of the University of Rochester's south campus, located in Brighton, New York. The lab was established in 1970 and its operations since then have been funded jointly; mainly by the United States Department of Energy, the University of Rochester and the New York State government. The Laser Lab was commissioned to serve as a center for investigations of high-energy physics, specifically those involving the interaction of extremely intense laser radiation with matter. Many types of scientific experiments are performed at the facility with a strong emphasis on inertial confinement, direct drive, laser-induced fusion, fundamental plasma physics and astrophysics using the Omega Laser Facility. In June 1995, OMEGA became the world's highest-energy ultraviolet laser."World's Most Powerful Ultraviolet Laser Comes On-line" http://www.rochester.edu/news/show.php?id=641 The lab shares its building with t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron
The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure. The electron's mass is approximately 1/1836 that of the proton. Quantum mechanical properties of the electron include an intrinsic angular momentum ( spin) of a half-integer value, expressed in units of the reduced Planck constant, . Being fermions, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Like all elementary particles, electrons exhibit properties of both particles and waves: They can collide with other particles and can be diffracted like light. The wave properties of electrons are easier to observe with experiments than those of other particles like neutrons and protons because electrons have a lower mass and hence a longer de Broglie wavele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around 1 millimeter (300 GHz) to the nominal red edge of the visible spectrum, around 700 nanometers (430 THz). Longer IR wavelengths (30 μm-100 μm) are sometimes included as part of the terahertz radiation range. Almost all black-body radiation from objects near room temperature is at infrared wavelengths. As a form of electromagnetic radiation, IR propagates energy and momentum, exerts radiation pressure, and has properties corresponding to both those of a wave and of a particle, the photon. It was long known that fires emit invisible heat; in 1681 the pioneering experimenter Edme Mariotte showed that glass, though transparent to sunlight, obstructed radiant heat. In 1800 the astronomer Sir William Herschel discovered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inertial Confinement Fusion
Inertial confinement fusion (ICF) is a fusion energy process that initiates nuclear fusion reactions by compressing and heating targets filled with thermonuclear fuel. In modern machines, the targets are small spherical pellets about the size of a pinhead typically containing a mixture of about 10 milligrams of deuterium 2H and tritium 3H. To compress and heat the fuel, energy is deposited in the outer layer of the target using high-energy beams of photons, electrons or ions, although almost all ICF devices used lasers. The beams heat the outer layer, which explodes outward. This produces a reaction force against the remainder of the target, which accelerates it inwards and compresses the fuel. This process also creates shock waves that travel inward through the target. Sufficiently powerful shock waves can compress and heat the fuel at the center such that fusion occurs. ICF is one of two major branches of fusion energy research, the other is magnetic confinement fusion. When ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
