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  • 1
    Electronic Resource
    Electronic Resource
    On the van Cittert-Zernike theorem (1972)
    Springer
    Optical and quantum electronics 4 (1972), S. 197-205 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The van Cittert-Zernike theorem states that the spatial coherence over a space illuminated by an incoherent extended source is described by the Fourier transform of the intensity distribution over the source. The theorem is usually used in a restricted case of the spatial coherence in a plane parallel to the source plane and illuminated by an incoherent extended source of uniform intensity distribution. In this paper we re-examine the van Cittert-Zernike theorem by reviewing it in an original formulation and extend the theorem to the spatial coherence at any two points of a light field illuminated by an incoherent extended source having a non-uniform intensity distribution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02334390
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of a turbulent medium on the near- and far-field diffraction of a circular aperture (1972)
    Springer
    Optical and quantum electronics 4 (1972), S. 235-247 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The near- and far-field diffraction due to a circular aperture illuminated with partially coherent light produced by a turbulent medium has been theoretically studied. Formulations are developed for investigating the near- and far-field diffraction patterns. The phase structure function, which is generated by the turbulent medium and determines the partially coherent condition of a light beam passing through it, is assumed to take both the Gaussian form and the 5/3-power law. Numerical results concerning the far-field intensity distribution and the axial intensity distribution in the near-field region are presented in diagrams and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02334394
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  • 3
    Electronic Resource
    Electronic Resource
    Some formulations of light scattering in laser flowmeters employing differential Doppler heterodyning (1972)
    Springer
    Optical and quantum electronics 4 (1972), S. 399-416 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The theory for the Doppler shifted light is developed by diffraction theory combined with galilean transformation. The theory developed is applied to a differential Doppler heterodyning technique in which two beams are brought simultaneously, but at different angles, into the same area, and the cross region made by the two beams becomes a probing volume. When the concentration of scattering particles is so low that only one particle is found in the probing volume, the theory can be classified into two cases of a single particle and many particles depending on the analysing time for the Fourier transform, i.e. whether the time, during which one particle passes through the probing volume, is longer than the observing time or not. When the concentration of particles in the probing volume becomes dense, the light scattered by the different particles interferes and the theory shows great complexity. The cases of two particles and many particles showing a very high density are studied. Comparisons are made for the difference between differential Doppler heterodyning and normal heterodyning techniques.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01414144
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  • 4
    Electronic Resource
    Electronic Resource
    Some effects of optical alignment errors in a differential laser Doppler velocimeter (1973)
    Springer
    Optical and quantum electronics 5 (1973), S. 517-532 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract A formulation has been developed to treat the effects of alignment errors of the optical system used in a differential laser Doppler velocimeter. It is then applied to analyse the properties of output beat signals obtained by the velocimeter. The effects of optical alignment errors on the spectral width and signal-to-noise ratio of the output beat signals and on the probing volume are investigated in some detail. The spectral width is not affected very much by the deviation of the angle between two beams incident on the probing volume, but depends mainly on the number of interference fringes produced in that volume. The signal-to-noise ratio is very sensitive to the displacement of two incident beams on the probing volume and is also affected by the intensity and beam width differences of these two beams. The probing volume is evaluated in the case of two incident beams having different beam widths.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02109657
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  • 5
    Electronic Resource
    Electronic Resource
    Velocity measurement of a diffuse object by using time-varying speckles (1976)
    Springer
    Optical and quantum electronics 8 (1976), S. 523-529 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The relation between the velocity of a moving diffuse object and the mean number of integrated speckles in the certain time interval at the far-field plane of the object is obtained. By using this relation based on the first order statistics of integrated speckles, a new method of measuring the velocity of the diffuse object is proposed and experimentally verified. The first order probability density function of time-integrated speckles is also studied from which the validity of the present method is verified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00620143
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of wall scattering on SNR in off-axis differential-type laser Doppler velocimetry (1983)
    Springer
    Optical and quantum electronics 15 (1983), S. 419-431 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract Though various properties and applications of laser Doppler velocimetry have been extensively studied in the past decade, there is little discussion on the effect of light scattering from the surface of a cell on Doppler beat signals or on methods of reducing it. In this paper, the effect of light scattering from the surface of the cell is treated as a background noise and is studied theoretically and experimentally on the detecting process of Doppler beat signals in off-axis differential-type laser Doppler velocimetry. Laser Doppler velocimetry of an off-axis type is verified to be effective for measurement of the flow velocity in the vicinity of a scattering wall. The effect of the light scattered from the wall surface on the signal-to-noise ratio (SNR) of Doppler beat signals is discussed in detail. The minimum distance, which is close to the wall and at which good Doppler beat signals can be obtained, is defined and determined quantitatively. This minimum distance is found to be strongly affected by the off-axis angle of the detecting optical system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00619864
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  • 7
    Electronic Resource
    Electronic Resource
    Spatial coherence of laser light passed through rotating ground glass (1970)
    Springer
    Optical and quantum electronics 2 (1970), S. 115-123 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The ensemble-averaged spatial coherence of quasi-thermal light, produced by passing a focused laser beam through a rotating ground glass plate, is studied as a function of the illuminated area, the fineness of the glass used, the speed of rotation of the glass, and the laser mode selected as a primary source. It becomes clear that the ensemble-averaged spatial coherence depends strongly upon the illuminated area and on the fineness of the rotating ground glass, and also on the laser mode chosen but not on the speed of rotation of the glass.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01415089
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  • 8
    Electronic Resource
    Electronic Resource
    First-order probability density function of the laser speckle phase (1980)
    Springer
    Optical and quantum electronics 12 (1980), S. 477-494 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract An expression for the first-order probability density function of the laser speckle phase is analytically derived under the assumption that the speckle field obeys a non-circular, complex Gaussian, random process with a certain correlation between the real and imaginary parts of its complex amplitude. The probability density function of the speckle phase is actually evaluated for various cases and shown three-dimensionally as a function of the standard deviation of random object phase variations. The effect of random object phase variations on the probability density function is also investigated in detail.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00619921
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  • 9
    Electronic Resource
    Electronic Resource
    Statistics of Gaussian Speckles with Enhanced Fluctuations (1995)
    Springer
    Optical review 2 (1995), S. 174-180 
    Details
    ISSN: 1349-9432
    Keywords: Gaussian speckle ; contrast enhancement ; non-circular statistics ; circularity ; gamma density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Some first-order statistics of speckle fields obeying the complex Gaussian probability density are investigated with the special emphasis on a possibility for the speckle contrast to exceed unity. It is shown that such enhanced fluctuations of speckle fields are generated when the probability density of the complex amplitude is non-circular with the vanishing mean. This means that Gaussian speckles having the contrast of unity are not necessarily fully developed speckles. Some practical situations producing such enhanced fluctuations in speckle fields are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10043-995-0174-z
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  • 10
    Electronic Resource
    Electronic Resource
    Retrieval of Optical Constants from Magnetoreflectance by Maximum Entropy Model (1998)
    Springer
    Optical review 5 (1998), S. 271-274 
    Details
    ISSN: 1349-9432
    Keywords: magnetoreflectance ; phase retrieval ; maximum entropy model ; Faraday configuration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Phase retrieval, and thereby retrieval of optical constants, from magnetoreflectance data is performed using the maximum entropy model for spectra analysis. The applicability of the analysis is tested by using the Lorentz model for the permittivity of a nonmagnetic insulator in a case of Faraday configuration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10043-998-0271-x
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