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Nonlinear Theory Of Semiconductor Lasers
Semiconductor laser theory, Laser theory of Fabry-Perot (FP) semiconductor lasers proves to be nonlinear, since the Gain (laser), gain,Noppe M G On Nonlinear Theory for Semiconductor Lasers. 2016 Laser Phys. 26055004 (doi:10.1088/1054-660X/26/5/055004) the refractive indexPartovi and E.M.Garmire, J. Appl.Phys, 69, 6885 (1991). and the loss coefficientSaid A A et al. Opt. Soc. Am. B 1992 9 405 are the functions of energy flux. The nonlinear theoryNoppe M.G. “Fundamentals of nonlinear theory for semiconductor lasers” (Publishing House SB RAS, 2016. Novosibirsk, 2016). (To purchase a monograph, please use the following link"Fundamentals of nonlinear theory for semiconductor lasers" made it possible to explain a number of experiments some of which could not even be explained (for example, natural Laser linewidth, linewidth), much less modeled, on the basis of other theoretical models; this suggests that the nonlinear theory developed is a new paradigm of the laser theory. Equati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semiconductor Laser Theory
Semiconductor lasers or laser diodes play an important part in our everyday lives by providing cheap and compact-size lasers. They consist of complex multi-layer structures requiring nanometer scale accuracy and an elaborate design. Their theoretical description is important not only from a fundamental point of view, but also in order to generate new and improved designs. It is common to all systems that the laser is an inverted carrier density system. The carrier inversion results in an electromagnetic polarization which drives an electric field E(t). In most cases, the electric field is confined in a resonator, the properties of which are also important factors for laser performance. Gain medium In semiconductor laser theory, the optical gain is produced in a semiconductor material. The choice of material depends on the desired wavelength and properties such as modulation speed. It may be a bulk semiconductor, but more often a quantum heterostructure. Pumping may be elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poynting Vector
In physics, the Poynting vector (or Umov–Poynting vector) represents the directional energy flux (the energy transfer per unit area per unit time) or ''power flow'' of an electromagnetic field. The SI unit of the Poynting vector is the watt per square metre (W/m2); kg/s3 in base SI units. It is named after its discoverer John Henry Poynting who first derived it in 1884. Nikolay Umov is also credited with formulating the concept. Oliver Heaviside also discovered it independently in the more general form that recognises the freedom of adding the curl of an arbitrary vector field to the definition. The Poynting vector is used throughout electromagnetics in conjunction with Poynting's theorem, the continuity equation expressing conservation of electromagnetic energy, to calculate the power flow in electromagnetic fields. Definition In Poynting's original paper and in most textbooks, the Poynting vector \mathbf is defined as the cross product \mathbf = \mathbf \times \mathbf, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wavelength Shift Δλ Versus Normalized Current
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. The inverse of the wavelength is called the spatial frequency. Wavelength is commonly designated by the Greek letter ''lambda'' (λ). The term ''wavelength'' is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids. Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency of the wave: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths. Wavelength depends on the medium (for example, vacuum, air, or water) that a wave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simulating Experimental Curve Of The Natural Linewidth Of Fabry-Perot Semiconductor Lasers
A simulation is the imitation of the operation of a real-world process or system over time. Simulations require the use of Conceptual model, models; the model represents the key characteristics or behaviors of the selected system or process, whereas the simulation represents the evolution of the model over time. Often, computers are used to execute the computer simulation, simulation. Simulation is used in many contexts, such as simulation of technology for performance tuning or optimizing, safety engineering, testing, training, education, and video games. Simulation is also used with scientific modelling of natural systems or human systems to gain insight into their functioning, as in economics. Simulation can be used to show the eventual real effects of alternative conditions and courses of action. Simulation is also used when the real system cannot be engaged, because it may not be accessible, or it may be dangerous or unacceptable to engage, or it is being designed bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Versus Energy Flux I For Two Sets Of Characteristic Parameters
Versus (Latin, 'against') may refer to: Film and television * ''Versus'' (2000 film), a Japanese zombie film * ''Versus'' (2016 film), a Russian sports drama film * ''Versus'' (2019 film), a French thriller film * Versus (TV channel), former name of NBCSN, an American sports channel * "Versus", an episode of ''Ninjago'' Music * ''Versus'', a trope in medieval music * Versus (band), an American rock band Albums * ''Versus'' (Carl Craig album), 2017 * ''Versus'' (Diaura album), 2017 * ''Versus'' (Emarosa album), 2014 * ''Versus'' (Kings of Convenience album), 2001 * ''Versus'' (Little Ghost album), 2015 * ''Versus'' (Mikael Gabriel album), 2015 * ''Versus'' (Mr. Children album), 1993 * ''Versus'' (The Haunted album), 2008 * ''Versus'', a 2017 album by Gloria Trevi with Alejandra Guzmán * ''VersuS'', a 2019 album by Vitaa with Slimane * ''Versus'' (EP), by Usher, 2010 Songs * "Versus", a 2015 single by Area 11 * "Versus", a song by Convergerack from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density Matrix
In quantum mechanics, a density matrix (or density operator) is a matrix that describes the quantum state of a physical system. It allows for the calculation of the probabilities of the outcomes of any measurement performed upon this system, using the Born rule. It is a generalization of the more usual state vectors or wavefunctions: while those can only represent pure states, density matrices can also represent ''mixed states''. Mixed states arise in quantum mechanics in two different situations: first when the preparation of the system is not fully known, and thus one must deal with a statistical ensemble of possible preparations, and second when one wants to describe a physical system which is entangled with another, without describing their combined state. Density matrices are thus crucial tools in areas of quantum mechanics that deal with mixed states, such as quantum statistical mechanics, open quantum systems, quantum decoherence, and quantum information. Definition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed Feedback Laser
A distributed-feedback laser (DFB) is a type of laser diode, quantum-cascade laser or optical-fiber laser where the active region of the device contains a periodically structured element or diffraction grating. The structure builds a one-dimensional interference grating ( Bragg scattering), and the grating provides optical feedback for the laser. This longitudinal diffraction grating has periodic changes in refractive index that cause reflection back into the cavity. The periodic change can be either in the real part of the refractive index or in the imaginary part (gain or absorption). The strongest grating operates in the first order, where the periodicity is one-half wave, and the light is reflected backwards. DFB lasers tend to be much more stable than Fabry–Perot or DBR lasers and are used frequently when clean single-mode operation is needed, especially in high-speed fiber-optic telecommunications. Semiconductor DFB lasers in the lowest loss window of optical fibers at a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incoherent Scattering
Incoherent scattering is a type of scattering phenomenon in physics. The term is most commonly used when referring to the scattering of an electromagnetic wave (usually light or radio frequency) by random fluctuations in a gas of particles (most often electrons). The most well known practical application is known as incoherent scatter radar theory, a ground-based technique for studying the Earth's ionosphere first proposed by Professor William E. Gordon in 1958. A radar beam scattering off electrons in the ionospheric plasma creates an incoherent scatter return. When an electromagnetic wave is transmitted through the atmosphere, each of the electrons in the ionospheric plasma essentially acts as an antenna excited by the incoming wave, and the wave is re-radiated from the electron. Since the electrons are all moving at varying speeds as a result of ionospheric dynamics and random thermal motion, the reflection from each electron is also Doppler shifted. The receiver on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Laser Medium
The active laser medium (also called gain medium or lasing medium) is the source of optical gain within a laser. The gain results from the stimulated emission of photons through electronic or molecular transitions to a lower energy state from a higher energy state previously populated by a pump source. Examples of active laser media include: * Certain crystals, typically doped with rare-earth ions (e.g. neodymium, ytterbium, or erbium) or transition metal ions (titanium or chromium); most often yttrium aluminium garnet ( Y3 Al5 O12), yttrium orthovanadate (YVO4), or sapphire (Al2O3); and not often Caesium cadmium bromide ( Cs Cd Br3) (Solid-state lasers) * Glasses, e.g. silicate or phosphate glasses, doped with laser-active ions; * Gases, e.g. mixtures of helium and neon (HeNe), nitrogen, argon, krypton, carbon monoxide, carbon dioxide, or metal vapors; ( Gas lasers) * Semiconductors, e.g. gallium arsenide (GaAs), indium gallium arsenide (InGaAs), or gallium nitride (GaN). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Resistivity And Conductivity
Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric current. A low resistivity indicates a material that readily allows electric current. Resistivity is commonly represented by the Greek letter (rho). The SI unit of electrical resistivity is the ohm-meter (Ω⋅m). For example, if a solid cube of material has sheet contacts on two opposite faces, and the resistance between these contacts is , then the resistivity of the material is . Electrical conductivity or specific conductance is the reciprocal of electrical resistivity. It represents a material's ability to conduct electric current. It is commonly signified by the Greek letter (sigma), but (kappa) (especially in electrical engineering) and ( gamma) are sometimes used. The SI unit of electrical conductivity is siemens per metre (S/m). Resistivity and conductivity are inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lasers
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light which is ''coherent''. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances (collimation), enabling applications such as laser pointers and lidar (light detection and ranging). Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum. Alternatively, temporal coherence can be used to produce ultrashort pulses of light wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
