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Nitrogen Laser
A nitrogen laser is a gas laser operating in the ultraviolet rangeC. S. Willett, ''Introduction to Gas Lasers: Population Inversion Mechanisms'' (Pergamon, New York,1974). (typically 337.1 nm) using molecular nitrogen as its gain medium, pumped by an electrical discharge. The wall-plug efficiency of the nitrogen laser is low, typically 0.1% or less, though nitrogen lasers with efficiency of up to 3% have been reported in the literature. The wall-plug efficiency is the product of the following three efficiencies: * electrical: TEA laser * gain medium: This is the same for all nitrogen lasers and thus has to be at least 3% ** inversion by electron impact is 10 to 1 due to Franck–Condon principle ** energy lost in the lower laser level: 40% * optical: More stimulated emission than spontaneous emission Gain medium The gain medium is nitrogen molecules in the gas phase. The nitrogen laser is a three-level laser. In contrast to more typical four-level lasers, the upper las ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oem Nitrogen Laser
An original equipment manufacturer (OEM) is generally perceived as a company that produces non-aftermarket parts and equipment that may be marketed by another manufacturer. It is a common industry term recognized and used by many professional organizations such as SAE International, ISO, and others. However, the term is also used in several other ways, which causes ambiguity. It sometimes means the maker of a system that includes other companies' subsystems, an end-product producer, an automotive part that is manufactured by the same company that produced the original part used in the automobile's assembly, or a value-added reseller.Ken Olsen: PDP-1 and PDP-8 (page 3) , economicadventure.com Automotive parts When referring to auto parts, OEM refers to the manufactur ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helium–neon Laser
A helium–neon laser or He-Ne laser, is a type of gas laser whose high energetic medium gain medium consists of a mixture of 10:1 ratio of helium and neon at a total pressure of about 1 torr inside of a small electrical discharge. The best-known and most widely used He-Ne laser operates at a wavelength of 632.8 nm, in the red part of the visible spectrum. History of He-Ne laser development The first He-Ne lasers emitted infrared at 1150 nm, and were the first gas lasers and the first lasers with continuous wave output. However, a laser that operated at visible wavelengths was much more in demand, and a number of other neon transitions were investigated to identify ones in which a population inversion can be achieved. The 633 nm line was found to have the highest gain in the visible spectrum, making this the wavelength of choice for most He-Ne lasers. However, other visible and infrared stimulated-emission wavelengths are possible, and by using mirror coating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photons
A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are Massless particle, massless, so they always move at the speed of light, speed of light in vacuum, (or about ). The photon belongs to the class of bosons. As with other elementary particles, photons are best explained by quantum mechanics and exhibit wave–particle duality, their behavior featuring properties of both waves and particles. The modern photon concept originated during the first two decades of the 20th century with the work of Albert Einstein, who built upon the research of Max Planck. While trying to explain how matter and electromagnetic radiation could be in thermal equilibrium with one another, Planck proposed that the energy stored within a material object should be regarded as composed of an integer number of discrete, equal-sized parts. To explai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inelastic Scattering
In chemistry, nuclear physics, and particle physics, inelastic scattering is a fundamental scattering process in which the kinetic energy of an incident particle is not conserved (in contrast to elastic scattering). In an inelastic scattering process, some of the energy of the incident particle is lost or increased. Although the term is historically related to the concept of inelastic collision in dynamics, the two concepts are quite distinct; inelastic collision in dynamics refers to processes in which the total macroscopic kinetic energy is not conserved. In general, scattering due to inelastic collisions will be inelastic, but, since elastic collisions often transfer kinetic energy between particles, scattering due to elastic collisions can also be ''in''elastic, as in Compton scattering meaning the two particles in the collision transfer energy causing a loss of energy in one particle. Electrons When an electron is the incident particle, the probability of inelastic scattering ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buffer Gas
A buffer gas is an inert or nonflammable gas. In the Earth's atmosphere, nitrogen acts as a buffer gas. A buffer gas adds pressure to a system and controls the speed of combustion with any oxygen present. Any inert gas such as helium, neon, or argon will serve as a buffer gas. Uses Buffer gases are commonly used in many applications from high pressure discharge lamps to reduce line width of microwave transitions in alkali atoms. A buffer gas usually consists of atomically inert gases such as helium, argon, and nitrogen which are the primary gases used. Krypton, neon, and xenon are also used, primarily for lighting. In most scenarios, buffer gases are used in conjunction with other molecules for the main purpose of causing collisions with the other co-existing molecules. In fluorescent lamps, mercury is used as the primary ion from which light is emitted. Krypton is the buffer gas used in conjunction with the mercury which is used to moderate the momentum of collisio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elastic Scattering
Elastic scattering is a form of particle scattering in scattering theory, nuclear physics and particle physics. In this process, the kinetic energy of a particle is conserved in the center-of-mass frame, but its direction of propagation is modified (by interaction with other particles and/or potentials) meaning the two particles in the collision do not lose energy.“Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for materials characterization,” B.J. Inkson, “Materials Characterization Using Nondestructive Evaluation (NDE) Methods,” 2016. https://www.sciencedirect.com/topics/chemistry/elastic-scattering Furthermore, while the particle's kinetic energy in the center-of-mass frame is constant, its energy in the lab frame is not. Generally, elastic scattering describes a process in which the total kinetic energy of the system is conserved. During elastic scattering of high-energy subatomic particles, linear energy transfer (LET) takes place unti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffusion
Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical potential. It is possible to diffuse "uphill" from a region of lower concentration to a region of higher concentration, like in spinodal decomposition. The concept of diffusion is widely used in many fields, including physics ( particle diffusion), chemistry, biology, sociology, economics, and finance (diffusion of people, ideas, and price values). The central idea of diffusion, however, is common to all of these: a substance or collection undergoing diffusion spreads out from a point or location at which there is a higher concentration of that substance or collection. A gradient is the change in the value of a quantity, for example, concentration, pressure, or temperature with the change in another variable, usually distance. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Field
An electric field (sometimes E-field) is the physical field that surrounds electrically charged particles and exerts force on all other charged particles in the field, either attracting or repelling them. It also refers to the physical field for a system of charged particles. Electric fields originate from electric charges and time-varying electric currents. Electric fields and magnetic fields are both manifestations of the electromagnetic field, one of the four fundamental interactions (also called forces) of nature. Electric fields are important in many areas of physics, and are exploited in electrical technology. In atomic physics and chemistry, for instance, the electric field is the attractive force holding the atomic nucleus and electrons together in atoms. It is also the force responsible for chemical bonding between atoms that result in molecules. The electric field is defined as a vector field that associates to each point in space the electrostatic ( Coulomb) for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Avalanche
An electron avalanche is a process in which a number of free electrons in a transmission medium are subjected to strong acceleration by an electric field and subsequently collide with other atoms of the medium, thereby ionizing them (impact ionization). This releases additional electrons which accelerate and collide with further atoms, releasing more electrons—a chain reaction. In a gas, this causes the affected region to become an electrically conductive plasma. The avalanche effect was discovered by John Sealy Townsend in his work between 1897 and 1901, and is also known as the Townsend discharge. Electron avalanches are essential to the dielectric breakdown process within gases. The process can culminate in corona discharges, streamers, leaders, or in a spark or continuous arc that completely bridges the gap between the electrical conductors that are applying the voltage. The process extends to huge sparks — streamers in lightning discharges propagate by form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Pressure
Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, 760mm Hg, 29.9212 inchesHg, or 14.696 psi.International Civil Aviation Organization. ''Manual of the ICAO Standard Atmosphere'', Doc 7488-CD, Third Edition, 1993. . The atm unit is roughly equivalent to the mean sea-level atmospheric pressure on Earth; that is, the Earth's atmospheric pressure at sea level is approximately 1 atm. In most circumstances, atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. As elevation increases, there is less overlying atmospheric mass, so atmospheric pressure decreases with increasing elevation. Because the atmosphere is thin relative to the Earth's radius—especially the dense atmospheric layer at low altitudes—the Earth's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Discharge
An electric discharge is the release and transmission of electricity in an applied electric field through a medium such as a gas (ie., an outgoing flow of electric current through a non-metal medium).American Geophysical Union, National Research Council (U.S.). Geophysics Study Committee (1986) ''The earth's electrical environment''. National Academy Press, Washington, DC, p. 263. Applications The properties and effects of electric discharges are useful over a wide range of magnitudes. Tiny pulses of current are used to detect ionizing radiation in a Geiger–Müller tube. A low steady current can be used to illustrate the spectrum of gases in a gas-filled tube. A neon lamp is an example of a gas-discharge lamp, useful both for illumination and as a voltage regulator. A flashtube generates a short pulse of intense light useful for photography by sending a heavy current through a gas arc discharge. Corona discharges are used in photocopiers. Electric discharges can convey su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffraction
Diffraction is defined as the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. The diffracting object or aperture effectively becomes a secondary source of the propagating wave. Italian scientist Francesco Maria Grimaldi coined the word ''diffraction'' and was the first to record accurate observations of the phenomenon in 1660. In classical physics, the diffraction phenomenon is described by the Huygens–Fresnel principle that treats each point in a propagating wavefront as a collection of individual spherical wavelets. The characteristic bending pattern is most pronounced when a wave from a coherent source (such as a laser) encounters a slit/aperture that is comparable in size to its wavelength, as shown in the inserted image. This is due to the addition, or interference, of different points on the wavefront (or, equivalently, each wavelet) that travel by paths of di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
