Author
Neal Brock
Bio: Neal Brock is an academic researcher. The author has contributed to research in topics: Interferometry & Astronomical interferometer. The author has an hindex of 18, co-authored 39 publications receiving 1380 citations.
Papers
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02 Aug 2004
TL;DR: In this article, a new type of dynamic measurement system that is comprised of a micropolarizer array and can work with any type polarization interferometer to measure a variety of physical properties is presented.
Abstract: We have demonstrated a new type of dynamic measurement system that is comprised of a micropolarizer array and can work with any type polarization interferometer to measure a variety of physical properties. The unique configuration overcomes many of the limitations of previous single frame, phase-shift interferometer techniques. In particular it has a true common path arrangement, is extremely compact, and is achromatic over a very wide range. We demonstrated high quality measurement with both a Twyman-Green and Fizeau type interferometer. The technique is useful for many applications where vibration or motion is intrinsic to the process.
285 citations
TL;DR: It is shown that the majority of error sources cause relatively small magnitude peak-to-valley errors in measurement of the order of 0.002-0.005lambda, which is largely mitigated by high-rate data acquisition and consequent data averaging.
Abstract: Recent technological innovations have enabled the development of a new class of dynamic (vibration-insensitive) interferometer based on a CCD pixel-level phase-shifting approach We present theoretical and experimental results for an interferometer based on this pixelated phase-shifting technique Analyses of component errors and instrument functionality are presented We show that the majority of error sources cause relatively small magnitude peak-to-valley errors in measurement of the order of 0002-0005lambda These errors are largely mitigated by high-rate data acquisition and consequent data averaging
220 citations
Patent•
21 Sep 2002
TL;DR: In this article, a wavefront-splitting element splits the combined wavefront into a plurality of sub-wavefronts in such a way that each of the sub wavefronts is substantially contiguous with at least one other subwavefront.
Abstract: Apparatus for splitting, imaging, and measuring wavefronts with a reference wavefront and an object wavefront. A wavefront-combining element receives and combines into a combined wavefront an object wavefront from an object and a reference wavefront. A wavefront-splitting element splits the combined wavefront into a plurality of sub-wavefronts in such a way that each of the sub-wavefronts is substantially contiguous with at least one other sub-wavefront. The wavefront-splitting element may shift the relative phase between the reference wavefront and the object wavefront of the sub-wavefronts to yield a respective plurality of phase-shifted sub-wavefronts. The wavefront-splitting element may then interfering the reference and object wavefronts of the phase-shifted sub-wavefronts to yield a respective plurality of phase-shifted interferograms. An imaging element receives and images the phase-shifted interferograms. A computer connected to the imaging element measures various parameters of the objects based on the phase-shifted interferograms. Examples of measurements include flow parameters such as the concentrations of selected gaseous species, temperature distributions, particle and droplet distributions, density, and so on. In addition to flow parameters, the displacement (e.g., the vibration) and the profile of an object may be measured.
134 citations
TL;DR: A division-of-focal-plane polarimeter based on a dichroic dye and liquid crystal polymer guest-host system is presented and two Stokes polarimeters are demonstrated: a linear Stokes and the first ever Full-Stokes division- of- focal- plane polarimeter.
Abstract: A division-of-focal-plane polarimeter based on a dichroic dye and liquid crystal polymer guest-host system is presented. Two Stokes polarimeters are demonstrated: a linear Stokes and the first ever Full-Stokes division-of-focal-plane polarimeter. The fabrication, packaging, and characterization of the systems are presented. Finally, optimized polarimeter designs are discussed for future works.
115 citations
TL;DR: The optimized full Stokes polarimeter, as defined by size of the standard deviation of the degree of circular polarization, is found to be approximately five times better than the performance of the simple full-Stokes polarimeters.
Abstract: In this paper, a full-Stokes imaging polarimeter operating at 580 nm using an array of elliptical polarizers is presented. The division-of-focal-plane polarimeter utilizes a set of four optimized measurements which represent a regular tetrahedron inscribed in the Poincare sphere. Results from the device fabrication, instrument calibration and characterization are presented. The performance of the optimized full Stokes polarimeter, as defined by size of the standard deviation of the degree of circular polarization, is found to be approximately five times better than the performance of the simple full-Stokes polarimeter.
95 citations
Cited by
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TL;DR: iPALM closes the gap between electron tomography and light microscopy, enabling both molecular specification and resolution of cellular nanoarchitecture.
Abstract: Understanding molecular-scale architecture of cells requires determination of 3D locations of specific proteins with accuracy matching their nanometer-length scale. Existing electron and light microscopy techniques are limited either in molecular specificity or resolution. Here, we introduce interferometric photoactivated localization microscopy (iPALM), the combination of photoactivated localization microscopy with single-photon, simultaneous multiphase interferometry that provides sub-20-nm 3D protein localization with optimal molecular specificity. We demonstrate measurement of the 25-nm microtubule diameter, resolve the dorsal and ventral plasma membranes, and visualize the arrangement of integrin receptors within endoplasmic reticulum and adhesion complexes, 3D protein organization previously resolved only by electron microscopy. iPALM thus closes the gap between electron tomography and light microscopy, enabling both molecular specification and resolution of cellular nanoarchitecture.
872 citations
TL;DR: Freeform optics is the next generation of modern optics, bringing advantages of excellent optical performance and system integration as mentioned in this paper, and finds wide applications in various fields, such as new energy, illumination, aerospace and biomedical engineering.
638 citations
TL;DR: Up-to-date see-through 3D display is a concept close to the ultimate goal of presenting seamless virtual images, although it is still far from practical use, many efforts have been made to resolve issues such as occlusion problems.
Abstract: Recent trends in three-dimensional (3D) display technologies are very interesting in that both old-fashioned and up-to-date technologies are being actively investigated together. The release of the first commercially successful 3D display product raised new research topics in stereoscopic display. Autostereoscopic display renders a ray field of a 3D image, whereas holography replicates a wave field of it. Many investigations have been conducted on the next candidates for commercial products to resolve existing limitations. Up-to-date see-through 3D display is a concept close to the ultimate goal of presenting seamless virtual images. Although it is still far from practical use, many efforts have been made to resolve issues such as occlusion problems.
331 citations
02 Aug 2004
TL;DR: In this article, a new type of dynamic measurement system that is comprised of a micropolarizer array and can work with any type polarization interferometer to measure a variety of physical properties is presented.
Abstract: We have demonstrated a new type of dynamic measurement system that is comprised of a micropolarizer array and can work with any type polarization interferometer to measure a variety of physical properties. The unique configuration overcomes many of the limitations of previous single frame, phase-shift interferometer techniques. In particular it has a true common path arrangement, is extremely compact, and is achromatic over a very wide range. We demonstrated high quality measurement with both a Twyman-Green and Fizeau type interferometer. The technique is useful for many applications where vibration or motion is intrinsic to the process.
285 citations
TL;DR: The single-shot 3D shape measurement techniques by projecting and capturing one fringe pattern image on the object surface, the wrapped phase demodulation algorithms from one captured image are reviewed.
284 citations