Détermination de la Surface de Cohérence à Partir d'une Expérience de Photocomptage

1972 ◽  
Vol 50 (8) ◽  
pp. 760-768 ◽  
Author(s):  
Jacques Bures ◽  
Claude Delisle ◽  
Andrzej Zardecki
Keyword(s):  
Degrees Of Freedom ◽  
Coherence Time ◽  
Theoretical Distribution ◽  
Detection Time ◽  
Coherent Light ◽  
Second Moment ◽  
Partially Coherent Light ◽  
Elementary Surface ◽  
The Mean ◽  
Circular Source

The theoretical distribution, with exact second moment, of the number of photoelectrons emitted by an extended photodetector illuminated with partially coherent light is first derived. Then the parameter N, the number of degrees of freedom, is obtained from the second moment of the distribution, for [Formula: see text] (T is the detection time and Tc the coherence time). N is then plotted as a function of the surface of the detector expressed in three different ways for both circular source and detector and square source and detector. In both cases the source is considered to be of uniform brightness. An elementary surface called the surface of coherence is determined by extrapolating towards small values the asymptotical behavior of N for large values of the detection surface. For both sources, this surface of coherence is equal to [Formula: see text]. λ0 is the mean wavelength, D the distance between the source and the detector, and Ss the surface of the source.

Distribution de la Somme des Photoélectrons Détectés en L Points sous Eclairement Gaussien Partiellement Cohérent

1971 ◽  
Vol 49 (24) ◽  
pp. 3064-3074 ◽  
Author(s):  
Jacques Bures ◽  
Claude Delisle ◽  
Andrzej Zardecki
Keyword(s):  
Experimental Verification ◽  
Spatial Coherence ◽  
Coherence Time ◽  
Thermal Source ◽  
General Function ◽  
Detection Time ◽  
Coherent Light ◽  
Second Moment ◽  
Partially Coherent Light ◽  
Spatial And Temporal Characteristics

The analysis of the photocount distribution in incoherent Gaussian light detected in L space points of a photodetector is extended to the case of partially coherent light. The second moment of the derived distribution is exact. A function η is introduced which accounts for the spatial coherence aspect of light as does the function ξ, (Mandel) for the temporal coherence aspect. A more general function ζ, which for cross-spectrally pure light reduces to the product ζ = ηξ, depends on both spatial and temporal characteristics of coherence. It is shown both theoretically and experimentally that many different geometrical configurations yield the same normalized second moment. A pseudo-thermal source [Formula: see text] where T is the detection time and Tc the coherence time) is used for the experimental verification.

The motion of a lunar orbiter

1966 ◽  
Vol 25 ◽  
pp. 373
Author(s):  
Y. Kozai
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Artificial Satellite ◽  
Equations Of Motion ◽  
Triaxial Ellipsoid ◽  
The Moon ◽  
Secular Motion ◽  
The Earth ◽  
Close Satellite ◽  
The Mean

The motion of an artificial satellite around the Moon is much more complicated than that around the Earth, since the shape of the Moon is a triaxial ellipsoid and the effect of the Earth on the motion is very important even for a very close satellite.The differential equations of motion of the satellite are written in canonical form of three degrees of freedom with time depending Hamiltonian. By eliminating short-periodic terms depending on the mean longitude of the satellite and by assuming that the Earth is moving on the lunar equator, however, the equations are reduced to those of two degrees of freedom with an energy integral.Since the mean motion of the Earth around the Moon is more rapid than the secular motion of the argument of pericentre of the satellite by a factor of one order, the terms depending on the longitude of the Earth can be eliminated, and the degree of freedom is reduced to one.Then the motion can be discussed by drawing equi-energy curves in two-dimensional space. According to these figures satellites with high inclination have large possibilities of falling down to the lunar surface even if the initial eccentricities are very small.The principal properties of the motion are not changed even if plausible values ofJ3andJ4of the Moon are included.This paper has been published in Publ. astr. Soc.Japan15, 301, 1963.

Lecture demonstrations on the interference of partially coherent light

1979 ◽  
Vol 129 (9) ◽  
pp. 151
Author(s):  
G.S. Egorov ◽  
S.N. Mensov ◽  
Nikolai S. Stepanov
Keyword(s):  
Coherent Light ◽  
Partially Coherent ◽  
Partially Coherent Light

Second harmonic generation using partially coherent light

1984 ◽  
Vol 51 (3) ◽  
pp. 207-212 ◽  
Author(s):  
James H. Churnside
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Coherent Light ◽  
Partially Coherent ◽  
Partially Coherent Light

New Results in Holography with Partially Coherent Light

1981 ◽  
Vol 10 (3) ◽  
pp. 51-56
Author(s):  
MIina Shah
Keyword(s):  
Coherent Light ◽  
Partially Coherent ◽  
Partially Coherent Light

Spatial correlation properties of twisted partially coherent light focused by diffractive axicons

2012 ◽  
Vol 29 (9) ◽  
pp. 2019 ◽  
Author(s):  
Mohamed Ali Shukri ◽  
Abdu. Ahmed Alkelly ◽  
Yaqoub Shamsaddeen Alarify
Keyword(s):  
Spatial Correlation ◽  
Coherent Light ◽  
Partially Coherent ◽  
Partially Coherent Light ◽  
Correlation Properties

Maximum Total Point Motion of Five Points Versus All Points in Assessing Tibial Baseplate Stability

2021 ◽  
Author(s):  
Abigail Niesen ◽  
Anna L Garverick ◽  
Maury Hull
Keyword(s):  
Degrees Of Freedom ◽  
Stability Limit ◽  
3D Models ◽  
Six Degrees Of Freedom ◽  
Percent Error ◽  
Model Based ◽  
Point Motion ◽  
The Mean ◽  
The Difference ◽  
Total Point

Abstract Maximum total point motion (MTPM), the point on a baseplate that migrates the most, has been used to assess the risk of tibial baseplate loosening using radiostereometric analysis (RSA). Two methods for determining MTPM for model-based RSA are to use either 5 points distributed around the perimeter of the baseplate or to use all points on the 3D model. The objectives were to quantify the mean difference in MTPM using 5 points vs. all points, compute the percent error relative to the 6-month stability limit for groups of patients, and to determine the dependency of differences in MTPM on baseplate size and shape. A dataset of 10,000 migration values was generated using the mean and standard deviation of migration in six degrees of freedom at 6 months from an RSA study. The dataset was used to simulate migration of 3D models (two baseplate shapes and two baseplate sizes) and calculate the difference in MTPM using 5 virtual points vs. all points and the percent error (i.e. difference in MTPM/stability limit) relative to the 6-month stability limit. The difference in MTPM was about 0.02 mm, or 4% percent relative to the 6-month stability limit, which is not clinically important. Furthermore, results were not affected by baseplate shape or size. Researchers can decide whether to use 5 points or all points when computing MTPM for model-based RSA. The authors recommend using 5 points to maintain consistency with marker-based RSA.

Research on Coupling Efficiency of Partially Coherent Light-Fiber Array Under Atmospheric Turbulence Channel

2021 ◽  
Vol 58 (5) ◽  
pp. 0501001-50100177
Author(s):  
雷思琛 Lei Sichen ◽  
南友新 Nan Youxin ◽  
杨玉峰 Yang Yufeng ◽  
吴鹏飞 Wu Pengfei
Keyword(s):  
Atmospheric Turbulence ◽  
Coupling Efficiency ◽  
Coherent Light ◽  
Fiber Array ◽  
Partially Coherent ◽  
Partially Coherent Light
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