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1.
Longitudinal coherence of an optical field depending on the parameters of its frequency and angular spectra is considered.
Expressions for the function and length of longitudinal coherence depending on the width of the frequency and angular spectra
are obtained. The competitive influence of the angular and frequency spectra of the field on its longitudinal coherence is
discussed. Experimental studies using a longitudinal shearing Michelson interferometer that proves theoretical results are
performed. 相似文献
2.
A method of reconstruction of the spatial phase distribution and the image of a scattering object from a recorded speckle pattern of the diffraction field has been developed and verified on test objects. The proposed method is based on an assumption that, for objects of a certain class, the phase difference between adjacent speckles in the far zone is equal to π. Digital records of Fourier speckle patterns and the corresponding digitally reconstructed images are presented. 相似文献
3.
V. P. Ryabukho A. L. Kal’yanov D. V. Lyakin V. V. Lychagov 《Optics and Spectroscopy》2010,108(6):979-984
Transverse spatial coherence of the optical field depending on parameters of angular and frequency spectra is considered.
Expressions for the function and length of the transverse coherence in relation to the widths of the angular and frequency
spectra are obtained. Experimental studies with a modified high-power Young interferometer that prove theoretical results
are performed. 相似文献
4.
Physical processes of interference pattern formation in partially coherent and coherent optical systems containing special diffractive optical elements with a double identical microstructure are studied in the case when a thin scattering object is present in the optical system. Methods for determining the spatial coherence function of the light field, the autocorrelation function of transmission of random phase screens, and the statistical parameters of the screens are considered. 相似文献
5.
Optics and Spectroscopy - The possibilities of reconstructing the hologram structure and image from a digitally recorded Fourier specklegram without reference beam have been considered. The... 相似文献
6.
A. B. Shipovskaya G. N. Timofeeva A. Yu. Abramov S. Yu. Shchegolev V. P. Ryabukho 《Polymer Science Series A》2010,52(2):126-133
The phenomenon of spontaneous changes in the linear dimensions (elongation-contraction) is described for commercial and laboratory
samples of acetate yarns processed by wet spinning from high- molecular -mass cellulose diacetate in vapors of a mesophas
ogenic solvent (which is able to form a lyotropic LC phase with the polymer), nitromethane, and its mixtures with water. The
thermodeformational, elastic- plastic, physicomechanical, and surface characteristics of the yarns at different stages of
their spontaneous deformation are analyzed. When samples are treated with probe vapors, orientational processes in the polymer
matrix are activated, and this observation makes it possible to prepare yarns with improved physicomechanical characteristics
and with low linear density. A new phenomenon (to our knowledge) of cyclic three- stage deformation of acetate monofilaments
in nitromethane vapors is discovered. This evidence is interpreted from the standpoint of phase (amorphous glassy-liquid crystalline
state) and conformational transitions as well as by the mechanism of interaction between polymers and solvent vapors and related
development of the LC phase. 相似文献
7.
Ryabukho V. P. Lychagov V. V. Lyakin D. V. Smirnov I. V. 《Optics and Spectroscopy》2011,110(5):802-805
The effects of the decoherence of a narrow-band optical field with a broad angular spectrum upon propagation through a plate
of a transparent medium placed in one of the arms of the Michelson interferometer are established. 相似文献
8.
The process of interference-pattern image formation in an optical system with a random phase screen in the space-frequency plane is analyzed. It is shown that an optical system of this kind can function, under certain conditions, as a shearing interferometer, which determines the dependence of contrast of the average intensity fringes in the interference pattern image on the normalized correlation function of the random phase screen complex transmittance. The dependence of the fringe contrast on the pattern period and aperture of the field of view is established, as well as dependence of the optical transfer function of the system under study on spatial coherence of the light in the pupil of the system with the random phase screen. 相似文献
9.
The possibility of using full-field low-coherence (white light) interferometry to investigate the surface profile and the
internal spatial structure of crystallized drops of blood plasma and to study plasma structuring in real time is discussed.
The experimental microtomograms of the central and peripheral regions of a plasma drop are presented. A method is proposed
to estimate the contact angle using two-dimensional cross sections of the drop optical structure in the peripheral region. 相似文献
10.
An experimental method for measurement of subpixel microdisplacements of speckle structure based on the parameters of the linear phase shift in the field of the complex spatial spectrum of the displaced structure is proposed and experimentally implemented. The phase shift is determined when a phase shift of spectrum is numerically added and the correlation analysis of the resulting linear phase shift in the spatial spectrum of specklegrams is performed. The method provides additional possibilities in the measurements using digital speckle photography when the period of interference fringes formed in the total spatial spectrum of specklegrams is significantly greater than the spectral width.
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