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Etendue
Etendue or étendue (; ) is a property of light in an optical system, which characterizes how "spread out" the light is in area and angle. It corresponds to the beam parameter product (BPP) in Gaussian beam optics. Other names for etendue include acceptance, throughput, light grasp, light-gathering power, optical extent, and the AΩ product. ''Throughput'' and ''AΩ product'' are especially used in radiometry and radiative transfer where it is related to the view factor (or shape factor). It is a central concept in nonimaging optics.Roland Winston et al.,, ''Nonimaging Optics'', Academic Press, 2004 Matthew S. Brennesholtz, Edward H. Stupp, ''Projection Displays'', John Wiley & Sons Ltd, 2008 From the source point of view, etendue is the product of the area of the source and the solid angle that the system's entrance pupil subtends as seen from the source. Equivalently, from the system point of view, the etendue equals the area of the entrance pupil times the solid angl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Etendue In Refraction
Etendue or étendue (; ) is a property of light in an optical system, which characterizes how "spread out" the light is in area and angle. It corresponds to the beam parameter product (BPP) in Gaussian beam optics. Other names for etendue include acceptance, throughput, light grasp, light-gathering power, optical extent, and the AΩ product. ''Throughput'' and ''AΩ product'' are especially used in radiometry and radiative transfer where it is related to the view factor (or shape factor). It is a central concept in nonimaging optics.Roland Winston et al.,, ''Nonimaging Optics'', Academic Press, 2004 Matthew S. Brennesholtz, Edward H. Stupp, ''Projection Displays'', John Wiley & Sons Ltd, 2008 From the source point of view, etendue is the product of the area of the source and the solid angle that the system's entrance pupil subtends as seen from the source. Equivalently, from the system point of view, the etendue equals the area of the entrance pupil times the solid angle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Etendue
Etendue or étendue (; ) is a property of light in an optical system, which characterizes how "spread out" the light is in area and angle. It corresponds to the beam parameter product (BPP) in Gaussian beam optics. Other names for etendue include acceptance, throughput, light grasp, light-gathering power, optical extent, and the AΩ product. ''Throughput'' and ''AΩ product'' are especially used in radiometry and radiative transfer where it is related to the view factor (or shape factor). It is a central concept in nonimaging optics.Roland Winston et al.,, ''Nonimaging Optics'', Academic Press, 2004 Matthew S. Brennesholtz, Edward H. Stupp, ''Projection Displays'', John Wiley & Sons Ltd, 2008 From the source point of view, etendue is the product of the area of the source and the solid angle that the system's entrance pupil subtends as seen from the source. Equivalently, from the system point of view, the etendue equals the area of the entrance pupil times the solid angl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Etendue For Differential Surface Element In 2D And 3D
Etendue or étendue (; ) is a property of light in an optical system, which characterizes how "spread out" the light is in area and angle. It corresponds to the beam parameter product (BPP) in Gaussian beam optics. Other names for etendue include acceptance, throughput, light grasp, light-gathering power, optical extent, and the AΩ product. ''Throughput'' and ''AΩ product'' are especially used in radiometry and radiative transfer where it is related to the view factor (or shape factor). It is a central concept in nonimaging optics.Roland Winston et al.,, ''Nonimaging Optics'', Academic Press, 2004 Matthew S. Brennesholtz, Edward H. Stupp, ''Projection Displays'', John Wiley & Sons Ltd, 2008 From the source point of view, etendue is the product of the area of the source and the solid angle that the system's entrance pupil subtends as seen from the source. Equivalently, from the system point of view, the etendue equals the area of the entrance pupil times the solid angle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamiltonian Optics
Hamiltonian opticsH. A. Buchdahl, ''An Introduction to Hamiltonian Optics'', Dover Publications, 1993, . and Lagrangian opticsVasudevan Lakshminarayanan et al., ''Lagrangian Optics'', Springer Netherlands, 2011, . are two formulations of geometrical optics which share much of the mathematical formalism with Hamiltonian mechanics and Lagrangian mechanics. Hamilton's principle In physics, Hamilton's principle states that the evolution of a system \left(q_1,\dots,q_N\right) described by N generalized coordinates between two specified states at two specified parameters ''σ''''A'' and ''σ''''B'' is a stationary point (a point where the variation is zero) of the action functional, or \delta S= \delta\int_^ L\left(q_1,\cdots,q_N,\dot_1,\cdots,\dot_N,\sigma\right)\, d\sigma=0 where \dot_k=dq_k/d\sigma and L is the Lagrangian. Condition \delta S=0 is valid if and only if the Euler-Lagrange equations are satisfied, i.e., \frac - \frac\frac = 0 with k = 1, \dots, N. The momentum is def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonimaging Optics
Nonimaging optics (also called anidolic optics)Roland Winston et al., ''Nonimaging Optics'', Academic Press, 2004 R. John Koshel (Editor), ''Illumination Engineering: Design with Nonimaging Optics'', Wiley, 2013 is the branch of optics concerned with the optimal transfer of light radiation between a source and a target. Unlike traditional imaging optics, the techniques involved do not attempt to form an image of the source; instead an optimized optical system for optimal radiative transfer from a source to a target is desired. Applications The two design problems that nonimaging optics solves better than imaging optics are: * solar energy concentration: maximizing the amount of energy applied to a receiver, typically a solar cell or a thermal receiver * illumination: controlling the distribution of light, typically so it is "evenly" spread over some areas and completely blocked from other areas Typical variables to be optimized at the target include the total radiant flux, the angu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
View Factor
In radiative heat transfer, a view factor, F_, is the proportion of the radiation which leaves surface A that strikes surface B. In a complex 'scene' there can be any number of different objects, which can be divided in turn into even more surfaces and surface segments. View factors are also sometimes known as configuration factors, form factors, angle factors or shape factors. Summation of view factors Because radiation leaving a surface is conserved, the sum of all view factors ''from'' a given surface, S_i, is unity: :\sum_^n = 1 For example, consider a case where two blobs with surfaces ''A'' and ''B'' are floating around in a cavity with surface ''C''. All of the radiation that leaves ''A'' must either hit ''B'' or ''C'', or if ''A'' is concave, it could hit ''A''. 100% of the radiation leaving ''A'' is divided up among ''A'', ''B'', and ''C''. Confusion often arises when considering the radiation that ''arrives'' at a ''target'' surface. In that case, it generally does n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
View Factor
In radiative heat transfer, a view factor, F_, is the proportion of the radiation which leaves surface A that strikes surface B. In a complex 'scene' there can be any number of different objects, which can be divided in turn into even more surfaces and surface segments. View factors are also sometimes known as configuration factors, form factors, angle factors or shape factors. Summation of view factors Because radiation leaving a surface is conserved, the sum of all view factors ''from'' a given surface, S_i, is unity: :\sum_^n = 1 For example, consider a case where two blobs with surfaces ''A'' and ''B'' are floating around in a cavity with surface ''C''. All of the radiation that leaves ''A'' must either hit ''B'' or ''C'', or if ''A'' is concave, it could hit ''A''. 100% of the radiation leaving ''A'' is divided up among ''A'', ''B'', and ''C''. Confusion often arises when considering the radiation that ''arrives'' at a ''target'' surface. In that case, it generally does n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gaussian Beam
In optics, a Gaussian beam is a beam of electromagnetic radiation with high monochromaticity whose amplitude envelope in the transverse plane is given by a Gaussian function; this also implies a Gaussian intensity (irradiance) profile. This fundamental (or TEM00) transverse Gaussian mode describes the intended output of most (but not all) lasers, as such a beam can be focused into the most concentrated spot. When such a beam is refocused by a lens, the transverse ''phase'' dependence is altered; this results in a ''different'' Gaussian beam. The electric and magnetic field amplitude profiles along any such circular Gaussian beam (for a given wavelength and polarization) are determined by a single parameter: the so-called waist . At any position relative to the waist (focus) along a beam having a specified , the field amplitudes and phases are thereby determinedSvelto, pp. 153–5. as detailed below. The equations below assume a beam with a circular cross-section at all va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimensionless Quantity
A dimensionless quantity (also known as a bare quantity, pure quantity, or scalar quantity as well as quantity of dimension one) is a quantity to which no physical dimension is assigned, with a corresponding SI unit of measurement of one (or 1), ISBN 978-92-822-2272-0. which is not explicitly shown. Dimensionless quantities are widely used in many fields, such as mathematics, physics, chemistry, engineering, and economics. Dimensionless quantities are distinct from quantities that have associated dimensions, such as time (measured in seconds). Dimensionless units are dimensionless values that serve as units of measurement for expressing other quantities, such as radians (rad) or steradians (sr) for plane angles and solid angles, respectively. For example, optical extent is defined as having units of metres multiplied by steradians. History Quantities having dimension one, ''dimensionless quantities'', regularly occur in sciences, and are formally treated within the field of d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Second Law Of Thermodynamics
The second law of thermodynamics is a physical law based on universal experience concerning heat and Energy transformation, energy interconversions. One simple statement of the law is that heat always moves from hotter objects to colder objects (or "downhill"), unless energy in some form is supplied to reverse the direction of heat flow. Another definition is: "Not all heat energy can be converted into Work (thermodynamics), work in a cyclic process."Young, H. D; Freedman, R. A. (2004). ''University Physics'', 11th edition. Pearson. p. 764. The second law of thermodynamics in other versions establishes the concept of entropy as a physical property of a thermodynamic system. It can be used to predict whether processes are forbidden despite obeying the requirement of conservation of energy as expressed in the first law of thermodynamics and provides necessary criteria for spontaneous processes. The second law may be formulated by the observation that the entropy of isolated systems ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entropy
Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynamics, where it was first recognized, to the microscopic description of nature in statistical physics, and to the principles of information theory. It has found far-ranging applications in chemistry and physics, in biological systems and their relation to life, in cosmology, economics, sociology, weather science, climate change, and information systems including the transmission of information in telecommunication. The thermodynamic concept was referred to by Scottish scientist and engineer William Rankine in 1850 with the names ''thermodynamic function'' and ''heat-potential''. In 1865, German physicist Rudolf Clausius, one of the leading founders of the field of thermodynamics, defined it as the quotient of an infinitesimal amount of hea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffuser (optics)
In optics, a diffuser (also called a light diffuser or optical diffuser) is any material that diffuses or scatters light in some manner to transmit soft light. Diffused light can be easily obtained by reflecting light from a white surface, while more compact diffusers may use translucent material, including ground glass, teflon, opal glass, and greyed glass. Types Perfect reflecting diffuser A perfect (reflecting) diffuser (PRD) is a theoretical perfectly white surface with Lambertian reflectance (its brightness appears the same from any angle of view). It does not absorb light, giving back 100% of the light it receives. Reflective diffusers can be easily characterised by scatterometers.{{cite web, url=http://www.zebraoptical.com/roughnessviascatterometry.html, title=Page Title, website=www.zebraoptical.com Diffractive diffuser/homogenizer A diffractive diffuser is a kind of diffractive optical element (DOE) that exploits the principles of diffraction and refraction. It uses d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
