Fringe sharpening in lateral shear interferometry
TL;DR: In this article, two methods of sharpening the interference fringes in lateral shear interferometry are described, one method exploits the non-linearity of the recording process, while the other is based on the characteristics of the multiply-recorded diffractive element.
Abstract: Two methods of sharpening the interference fringes in lateral shear interferometry are described. One method exploits the non-linearity of the recording process, while the other is based on the characteristics of the multiply-recorded diffractive element. Both methods can be combined to obtain further fringe sharpening in the higher orders.
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TL;DR: Multiple-beam interferometry results in sharpened fringes; hence the multiple-beam wedge-plate shear interferometer displays the lateral aberration curve of a lens sharply, provided the shear is small.
Abstract: Lateral shear interferometry is used to obtain the lateral aberrations of a lens. The zeroth-order fringe in an interferogram obtained from a wedge-plate lateral shear interferometer, however, directly displays the lateral aberration curve of a test lens. Nevertheless, the intensity distribution, is cosinusoidal. Multiple-beam interferometry results in sharpened fringes; hence the multiple-beam wedge-plate shear interferometer displays the lateral aberration curve of a lens sharply, provided the shear is small. For large shear, some new artifacts appear in the interferogram, which are also explained.
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TL;DR: In this article, a technique to record rainbow holograms in a single step is described, which is based on the realisation of a synthetic slit with low side-lobes.
Abstract: A technique to record rainbow holograms in a single step is described. The technique is based on the realisation of a synthetic slit. The synthetic slit with low side-lobes is generated by multiple exposures; The imaging lens is translated discretely between exposures. Finer slit is realised by increasing the number of exposures.
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TL;DR: The second edition of this respected text considerably expands the original and reflects the tremendous advances made in the discipline since 1968 as discussed by the authors, with a special emphasis on applications to diffraction, imaging, optical data processing, and holography.
Abstract: The second edition of this respected text considerably expands the original and reflects the tremendous advances made in the discipline since 1968. All material has been thoroughly updated and several new sections explore recent progress in important areas, such as wavelength modulation, analog information processing, and holography. Fourier analysis is a ubiquitous tool with applications in diverse areas of physics and engineering. This book explores these applications in the field of optics with a special emphasis on applications to diffraction, imaging, optical data processing, and holography. This book can be used as a textbook to satisfy the needs of several different types of courses, and it is directed toward both engineers ad physicists. By varying the emphasis on different topics and specific applications, the book can be used successfully in a wide range of basic Fourier Optics or Optical Signal Processing courses.
12,159 citations
Book•
01 Jan 1968
TL;DR: The second edition of this respected text considerably expands the original and reflects the tremendous advances made in the discipline since 1968 as discussed by the authors, with a special emphasis on applications to diffraction, imaging, optical data processing, and holography.
Abstract: The second edition of this respected text considerably expands the original and reflects the tremendous advances made in the discipline since 1968. All material has been thoroughly updated and several new sections explore recent progress in important areas, such as wavelength modulation, analog information processing, and holography. Fourier analysis is a ubiquitous tool with applications in diverse areas of physics and engineering. This book explores these applications in the field of optics with a special emphasis on applications to diffraction, imaging, optical data processing, and holography. This book can be used as a textbook to satisfy the needs of several different types of courses, and it is directed toward both engineers ad physicists. By varying the emphasis on different topics and specific applications, the book can be used successfully in a wide range of basic Fourier Optics or Optical Signal Processing courses.
9,800 citations
TL;DR: In this article, the authors measured local displacements in the plane of an object surface illuminated by coherent light by recording double-exposure photographs of it and using the optical transform of the negative image.
Abstract: Local displacements in the plane of an object surface illuminated by coherent light may be measured by recording double-exposure photographs of it. When the surface is illuminated symmetrically by two oblique beams, ‘speckle correlation fringes’ appear in the doubly exposed negative, due to the non-linear nature of the photographic recording. Factors affecting the visibility of these fringes and the range of displacement which can be measured are discussed. The fringe visibility falls to zero for displacements larger than a speckle width, but measurements can then be performed upon the optical transform of the negative image. With uni-directional object illumination, the in-plane displacement can be measured on a point-by-point basis in magnitude and in direction from Young's fringes observed. With two symmetrical oblique illuminating beams the effect of a small surface strain is displayed, even if large lateral displacement has occurred, by using spatial filtering when viewing the photographic image.
302 citations
TL;DR: In this paper, the effect of diffraction gratings on the path of a wave affected by any aberration is investigated from an interferential viewpoint and a wave theory of shadows is formulated.
Abstract: The present paper deals with the development of studies concerning the employment of diffraction gratings as interferometers, starting in 1922 when they were used to test optical systems. After reporting how a concave surface was tested by means of gratings their elementary theory is described. The phenomenon is further studied from the interferential standpoint and a wave theory of shadows formulated which is analogous to Abbe’s theory on images. A series of studies follows demonstrating that interferential theory accounts for the form of the fringes recorded when a grating is placed on the path of a wave affected by any aberration. In conclusion some simple rules are derived which allow evaluation of both the quality and the amount of the aberration of the wave under test on the basis of the form of the fringes. The sensitivity of the method is then studied, and the most recent developments and better-known applications of the gratings reported concerning their employment as achromatic interferometers.
255 citations
TL;DR: Results indicate that small wavefront aberrations can be measured as accurately with the lateral-shear interferometer as with the Twyman-Green interferometers and that aberration that cannot be measured at all with a Twy man-Greeninterferometer can be measurement to about 1% accuracy or better.
Abstract: A variable shear lateral shearing interferometer consisting of two holographically produced crossed diffraction gratings is used to test nonrotationally symmetric wavefronts having aberrations greater than 100 wavelengths and slope variations of more than 400 wavelengths/diameter. Comparisons are made with results of Twyman-Green interferometric tests for wavefront aberrations of up to thirty wavelengths. The results indicate that small wavefront aberrations can be measured as accurately with the lateral-shear interferometer as with the Twyman-Green interferometer and that aberrations that cannot be measured at all with a Twyman-Green interferometer can be measured to about 1% accuracy or better.
158 citations