1,166 research outputs found
Absorbing new subjects: holography as an analog of photography
I discuss the early history of holography and explore how perceptions, applications, and forecasts of the subject were shaped by prior experience. I focus on the work of Dennis Gabor (1900–1979) in England,Yury N. Denisyuk (b. 1924) in the Soviet Union, and Emmett N. Leith (1927–2005) and Juris Upatnieks (b. 1936) in the United States. I show that the evolution of holography was simultaneously promoted and constrained by its identification as an analog of photography, an association that influenced its assessment by successive audiences of practitioners, entrepreneurs, and consumers. One consequence is that holography can be seen as an example of a modern technical subject that has been shaped by cultural influences more powerfully than generally appreciated.
Conversely, the understanding of this new science and technology in terms of an older one helps
to explain why the cultural effects of holography have been more muted than anticipated by forecasters
between the 1960s and 1990s
Attributing scientific and technical progress: the case of holography
Holography, the three-dimensional imaging technology, was portrayed widely as a paradigm
of progress during its decade of explosive expansion 1964–73, and during its subsequent
consolidation for commercial and artistic uses up to the mid 1980s. An unusually
seductive and prolific subject, holography successively spawned scientific insights, putative
applications and new constituencies of practitioners and consumers. Waves of forecasts,
associated with different sponsors and user communities, cast holography as a field on the
verge of success—but with the dimensions of success repeatedly refashioned. This retargeting
of the subject represented a degree of cynical marketeering, but was underpinned by
implicit confidence in philosophical positivism and faith in technological progressivism.
Each of its communities defined success in terms of expansion, and anticipated continual
progressive increase. This paper discusses the contrasting definitions of progress in holography,
and how they were fashioned in changing contexts. Focusing equally on reputed ‘failures’ of some aspects of the subject, it explores the varied attributes by which success and failure were linked with progress by different technical communities. This important case illuminates the peculiar post-World War II environment that melded the military, commercial and popular engagement with scientific and technological subjects, and the
competing criteria by which they assessed the products of science
Attributing scientific and technological progress: The case of holography
Holography, the three-dimensional imaging technology, was portrayed widely as a paradigm of progress during its decade of explosive expansion 1964–73, and during its subsequent consolidation for commercial and artistic uses up to the mid 1980s. An unusually seductive and prolific subject, holography successively spawned scientific insights, putative applications and new constituencies of practitioners and consumers. Waves of forecasts, associated with different sponsors and user communities, cast holography as a field on the verge of success—but with the dimensions of success repeatedly refashioned. This retargeting of the subject represented a degree of cynical marketeering, but was underpinned by implicit confidence in philosophical positivism and faith in technological progressivism. Each of its communities defined success in terms of expansion, and anticipated continual progressive increase. This paper discusses the contrasting definitions of progress in holography, and how they were fashioned in changing contexts. Focusing equally on reputed ‘failures’ of some aspects of the subject, it explores the varied attributes by which success and failure were linked with progress by different technical communities. This important case illuminates the peculiar post-World War II environment that melded the military, commercial and popular engagement with scientific and technological subjects, and the competing criteria by which they assessed the products of science
Gradient metasurfaces: a review of fundamentals and applications
In the wake of intense research on metamaterials the two-dimensional
analogue, known as metasurfaces, has attracted progressively increasing
attention in recent years due to the ease of fabrication and smaller insertion
losses, while enabling an unprecedented control over spatial distributions of
transmitted and reflected optical fields. Metasurfaces represent optically thin
planar arrays of resonant subwavelength elements that can be arranged in a
strictly or quasi periodic fashion, or even in an aperiodic manner, depending
on targeted optical wavefronts to be molded with their help. This paper reviews
a broad subclass of metasurfaces, viz. gradient metasurfaces, which are devised
to exhibit spatially varying optical responses resulting in spatially varying
amplitudes, phases and polarizations of scattered fields. Starting with
introducing the concept of gradient metasurfaces, we present classification of
different metasurfaces from the viewpoint of their responses, differentiating
electrical-dipole, geometric, reflective and Huygens' metasurfaces. The
fundamental building blocks essential for the realization of metasurfaces are
then discussed in order to elucidate the underlying physics of various physical
realizations of both plasmonic and purely dielectric metasurfaces. We then
overview the main applications of gradient metasurfaces, including waveplates,
flat lenses, spiral phase plates, broadband absorbers, color printing,
holograms, polarimeters and surface wave couplers. The review is terminated
with a short section on recently developed nonlinear metasurfaces, followed by
the outlook presenting our view on possible future developments and
perspectives for future applications.Comment: Accepted for publication in Reports on Progress in Physic
Reconstruction of a 3-dimensional transonic rotor flow field from holographic interferogram data
Holographic interferometry and computer-assisted tomography (CAT) are used to determine the transonic velocity field of a model rotor blade in hover. A pulsed ruby laser recorded 40 interferograms with a 2-ft-diam view field near the model rotor-blade tip operating at a tip Mach number of 0.90. After digitizing the interferograms and extracting fringe-order functions, the data are transferred to a CAT code. The CAT code then calculates the perturbation velocity in seeral planes above the blade surface. The values from the holography-CAT method compare favorably with previously obtained numerical computations in most locations near the blade tip. The results demonstrate the technique's potential for three-dimensional transonic rotor flow studies
Reconstruction of a three-dimensional, transonic rotor flow field from holographic interferogram data
Holographic interferometry and computerized aided tomography (CAT) are used to determine the transonic velocity field of a model rotor blade in hover. A pulsed ruby laser recorded 40 interferograms with a 2 ft dia view field near the model rotor blade tip operating at a tip Mach number of 0.90. After digitizing the interferograms and extracting the fringe order functions, the data are transferred to a CAT code. The CAT code then calculates the perturbation velocity in several planes above the blade surface. The values from the holography-CAT method compare favorably with previously obtained numerical computations in most locations near the blade tip. The results demonstrate the technique's potential for three dimensional transonic rotor flow studies
Improving reconstructions of digital holograms
Digital holography is a two step process of recording a hologram on an electronic
sensor and reconstructing it numerically. This thesis makes a number of contri-
butions to the second step of this process. These can be split into two distinct
parts: A) speckle reduction in reconstructions of digital holograms (DHs), and
B) modeling and overcoming partial occlusion e®ects in reconstructions of DHs,
and using occlusions to reduce the effects of the twin image in reconstructions of
DHs. Part A represents the major part of this thesis. Speckle reduction forms an
important step in many digital holographic applications and we have developed
a number of techniques that can be used to reduce its corruptive effect in recon-
structions of DHs. These techniques range from 3D filtering of DH reconstructions
to a technique that filters in the Fourier domain of the reconstructed DH. We have
also investigated the most commonly used industrial speckle reduction technique
- wavelet filters. In Part B, we investigate the nature of opaque and non-opaque
partial occlusions. We motivate this work by trying to ¯nd a subset of pixels
that overcome the effects of a partial occlusion, thus revealing otherwise hidden
features on an object captured using digital holography. Finally, we have used an
occlusion at the twin image plane to completely remove the corrupting effect of
the out-of-focus twin image on reconstructions of DHs
Holographic optical elements: Fabrication and testing
The basic properties and use of holographic optical elements were investigated to design and construct wide-angle, Fourier-transform holographic optical systems for use in a Bragg-effect optical memory. The performance characteristics are described along with the construction of the holographic system
Some applications of holographic interferometry and Speckle correlation techniques to the study of plant growth and physiology
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