Measure of the "spread" of light in an optical system
Conservation of etendue
Etendue or étendue (/ˌeɪtɒnˈduː/; French pronunciation:[etɑ̃dy]) 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,[1] 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.[2][page needed][3][page needed][4][page needed]
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 the source subtends as seen from the pupil. These definitions must be applied for infinitesimally small "elements" of area and solid angle, which must then be summed over both the source and the diaphragm as shown below. Etendue may be considered to be a volume in phase space.
Etendue never decreases in any optical system where optical power is conserved.[5] A perfect optical system produces an image with the same etendue as the source. The etendue is related to the Lagrange invariant and the optical invariant, which share the property of being constant in an ideal optical system. The radiance of an optical system is equal to the derivative of the radiant flux with respect to the etendue.
^"Optical extent / Etendue". CIE e-ILV: International Lighting Vocabulary (2nd ed.). International Commission on Illumination. 17-21-048. Retrieved 19 February 2022.
^Chaves, Julio (2015). Introduction to Nonimaging Optics (2nd ed.). CRC Press. ISBN 978-1482206739.
^Winston, Roland; Minano, Juan C.; Benitez, Pablo G. (2004). Nonimaging Optics. Academic Press. ISBN 978-0127597515.
^Brennesholtz, Matthew S.; Stupp, Edward H. (2008). Projection Displays. John Wiley & Sons. ISBN 978-0470518038.
^"Basic Optics: Radiance" (PDF) (Lecture notes). Astronomy 525. College of Saint Benedict and Saint John's University.
Etendue or étendue (/ˌeɪtɒnˈduː/; French pronunciation: [etɑ̃dy]) is a property of light in an optical system, which characterizes how "spread out" the...
system. The volume occupied by a set of rays in phase space is called etendue, which is conserved as light rays progress in the optical system along...
surface is immersed; G is the étendue of the light beam. As the light travels through an ideal optical system, both the étendue and the radiant flux are conserved...
stationary medium. The term étendue is used to focus attention specifically on the geometrical aspects. The reciprocal character of étendue is indicated in the...
}=n^{2}{\frac {\mathrm {d} \Phi _{\mathrm {v} }}{\mathrm {d} G}}} where dG is the etendue of an infinitesimally narrow beam containing the specified ray; dΦv is...
potentially powerful, did not yet find a practical application. Conservation of etendue is a central concept in nonimaging optics. In concentration optics, it...
November 1914. L. Torres Quevedo. Essais sur l'Automatique - Sa définition. Etendue théorique de ses applications Archived 2023-02-10 at the Wayback Machine...
Ж2 is proportional to the throughput of the optical system (related to étendue). For a given optical system, the Lagrange invariant is a constant throughout...
Torres Quevedo. L. (1915). "Essais sur l'Automatique – Sa définition. Etendue théorique de ses applications", Revue Génerale des Sciences Pures et Appliquées...
a projected area and the solid angle; this product is often called the etendue. This step can be obviated by the use of a calibrated source, where the...
pupil to a pixel's photoreceptor the geometrical extent (also known as etendue or light throughput) of the objective lens / pixel system must be smaller...
al., 1995, pp. 24–25 "Iris Cantor Donates Gustave Caillebotte Femme nue étendue sur un Divan to Met". Urban Art and Antiques; Antique News; Art News. 24...
concentrators, Solar Energy 92 (2013) 98–105 Diogo Canavarro et al., Infinitesimal etendue and Simultaneous Multiple Surface (SMS) concentrators for fixed receiver...
Torres Quevedo. L. (1915). "Essais sur l'Automatique - Sa définition. Etendue théorique de ses applications", Revue Génerale des Sciences Pures et Appliquées...
LookLex. Tillier, Mathieu (5 December 2009), "I – Les districts et leur étendue", Les cadis d'Iraq et l'État Abbasside (132/750-334/945), Études arabes...
Wilderstein Institute. p. 60. "Iris Cantor Donates Gustave Caillebotte Femme nue étendue sur un Divan to Met". Urban Art and Antiques; Antique News; Art News. 24...
Since the rays of a laser beam are monochromatic and parallel (i.e. zero etendue) it can be focused to a small diameter and can produce as much as 100 MW...
Torres Quevedo. L. (1915). "Essais sur l'Automatique - Sa définition. Etendue théorique de ses applications", Revue Génerale des Sciences Pures et Appliquées...
single digital micromirror device for multi-image output and nearly-doubled étendue". Optics Express. 27 (15): 21477. doi:10.1364/oe.27.021477. hdl:10150/633995...
s^{2}}}\,{\hbox{d}}A_{2}\,{\hbox{d}}A_{1}.} The view factor is related to the etendue. For complex geometries, the view factor integral equation defined above...
Sciences Pures et Appliquées", Essais sur l'Automatique - Sa définition. Etendue théorique de ses applications, vol. 2, pp. 601–611 Randall B (1982), "From...
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