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  2. Rayleigh length - Wikipedia

    en.wikipedia.org/wiki/Rayleigh_length

    Gaussian beam width () as a function of the axial distance .: beam waist; : confocal parameter; : Rayleigh length; : total angular spread In optics and especially laser science, the Rayleigh length or Rayleigh range, , is the distance along the propagation direction of a beam from the waist to the place where the area of the cross section is doubled. [1]

  3. Rayleigh distance - Wikipedia

    en.wikipedia.org/wiki/Rayleigh_distance

    Rayleigh distance in optics is the axial distance from a radiating aperture to a point at which the path difference between the axial ray and an edge ray is λ / 4. An approximation of the Rayleigh Distance is Z = D 2 2 λ {\displaystyle Z={\frac {D^{2}}{2\lambda }}} , in which Z is the Rayleigh distance, D is the aperture of radiation, λ the ...

  4. Gaussian beam - Wikipedia

    en.wikipedia.org/wiki/Gaussian_beam

    The Gaussian function has a 1/e 2 diameter (2w as used in the text) about 1.7 times the FWHM.. At a position z along the beam (measured from the focus), the spot size parameter w is given by a hyperbolic relation: [1] = + (), where [1] = is called the Rayleigh range as further discussed below, and is the refractive index of the medium.

  5. Rayleigh scattering - Wikipedia

    en.wikipedia.org/wiki/Rayleigh_scattering

    Rayleigh scattering (/ ˈ r eɪ l i / RAY-lee) is the scattering or deflection of light, or other electromagnetic radiation, by particles with a size much smaller than the wavelength of the radiation.

  6. Angular resolution - Wikipedia

    en.wikipedia.org/wiki/Angular_resolution

    The result, θ = 4.56/D, with D in inches and θ in arcseconds, is slightly narrower than calculated with the Rayleigh criterion. A calculation using Airy discs as point spread function shows that at Dawes' limit there is a 5% dip between the two maxima, whereas at Rayleigh's criterion there is a 26.3% dip. [3]

  7. Rayleigh - Wikipedia

    en.wikipedia.org/wiki/Rayleigh

    Rayleigh length; Rayleigh number, a dimensionless number for a fluid associated with buoyancy driven flow; Rayleigh quotient; Rayleigh–Ritz method; Plateau–Rayleigh instability explains why a falling stream of fluid breaks up into smaller packets; Rayleigh–Taylor instability an instability of an interface between two fluids

  8. Distributed acoustic sensing - Wikipedia

    en.wikipedia.org/wiki/Distributed_acoustic_sensing

    In Rayleigh scatter-based distributed fiber optic sensing, a coherent laser pulse is sent along an optic fiber, and scattering sites within the fiber cause the fiber to act as a distributed interferometer with a gauge length approximately equal to the pulse length. The intensity of the reflected light is measured as a function of time after ...

  9. Optical resolution - Wikipedia

    en.wikipedia.org/wiki/Optical_resolution

    The original application called for placing the chart at a distance 26 times the focal length of the imaging lens used. The bars above and to the left are in sequence, separated by approximately the square root of two (12, 17, 24, etc.), while the bars below and to the left have the same separation but a different starting point (14, 20, 28, etc.)