Method of measuring linear displacements of objects based on Fresnel diffraction pattern position

2017 ◽  
Author(s):  
Anvar K. Zakirov ◽  
Alexander N. Ivanov ◽  
Ksenia V. Nizhegorodova ◽  
Ramil I. Minnigazimov ◽  
Vyacheslav V. Porokhin
Keyword(s):  
Diffraction Pattern ◽  
Fresnel Diffraction

XIV.—Experiments in Diffraction Microscopy

1952 ◽  
Vol 63 (3) ◽  
pp. 193-221 ◽  
Author(s):  
G. L. Rogers
Keyword(s):  
Diffraction Pattern ◽  
Elementary Theory ◽  
Focal Length ◽  
Fresnel Diffraction ◽  
Optical Methods ◽  
Zone Plate ◽  
Preliminary Trial ◽  
Adequate Information ◽  
Power Rate ◽  
Diffraction Microscopy

SynopsisExperiments have been performed, using purely optical methods, to verify and extend the theory of Gabor's diffraction microscope. An elementary theory of the process is first given, from which certain generalizations are provisionally drawn. In particular, a focal length is attributed to any Fresnel diffraction pattern and the hologram derived from it by photography. The variation of this focal length with wavelength and scale factor is postulated by analogy with a zone-plate, and the power-rate for a hologram is denned. These deductions are then verified by experiment, and a summary is given at the end of § 10. Various other confirmatory experiments are then described.Adequate information is given about apparatus and technique to enable new entrants into this field to obtain satisfactory results with the minimum of preliminary trial.

THE E-PLANE RADIATION PATTERN OF SHORT ELECTROMAGNETIC HORNS OF LARGE APERTURE

1947 ◽  
Vol 25a (6) ◽  
pp. 315-321 ◽  
Author(s):  
G. A. Woonton ◽  
J. G. Tillotson
Keyword(s):  
Electromagnetic Field ◽  
Diffraction Pattern ◽  
Radiation Pattern ◽  
Wave Length ◽  
Angular Position ◽  
Fresnel Diffraction ◽  
Experimental Results ◽  
Electric Vector ◽  
Theoretical Predictions ◽  
Good Agreement

The relation between the power received by a short, rectangular, electromagnetic horn, and its angular position in a plane electromagnetic field can be calculated, for rotation in the plane of the electric vector, from ordinary optical theory by assuming that the aperture produces at the throat a Fresnel diffraction pattern appropriate to the angular position of the aperture. Experimental results for four horns of slant lengths 25, 50, 100, and 176 cm., but all of the same aperture, 10λ to a side at a wave length of 3.2 cm., are in good agreement with the theoretical predictions at angles up to [Formula: see text] radian from the axis, for slant lengths down to 50 cm. but not down to 25 cm.

Diffraction from an irregular screen with applications to ionospheric problems

1950 ◽  
Vol 242 (856) ◽  
pp. 579-607 ◽  
Keyword(s):  
Diffraction Pattern ◽  
Angular Spectrum ◽  
Fresnel Diffraction ◽  
Radio Waves ◽  
Fraunhofer Diffraction ◽  
Related Method ◽  
Auto Correlation ◽  
Auto Correlation Function ◽  
Diffraction Patterns ◽  
Diffraction Effects

An analysis is made of the diffraction effects produced when a plane wave is incident upon an irregular diffracting screen, and the results are applied to the problem of the reflexion of radio waves from an ionosphere which is irregular in the horizontal plane. The nature of the irregular screen is assumed to be given in terms of the variation of electric wave-field in a plane just beyond the screen, and it is assumed that variations occur over the plane in one direction only. It is further assumed that the screen is 'random’ in the sense that it is one of an assembly all of which differ from each other, but have statistical properties in common, and deductions are made about the diffraction patterns averaged over the assembly. It is shown that many aspects of the problem can be investigated by use of the theory of ‘random’ electrical noise as developed by Rice and Uhlenbeck. The angular spectrum (Fraunhofer diffraction pattern) and the Fresnel diffraction pattern are described in terms of their spatial auto-correlation functions, and there is some discussion of a related method of dealing with Fresnel diffraction problems from completely determined screens. In part II of the paper the irregular ‘fading’ exhibited by a radio wave returned from the ionosphere is discussed in terms of two models in which the fading is assumed to be produced by movements of the diffracting centres in the ionosphere. The temporal auto-correlation function of the amplitude of the irregularly fading signal is related to the velocity of the ionospheric diffracting centres.

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