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Development and Application of Optical Coherence Tomography (Oct)

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ISBN: 9783038427445 9783038427438 Year: Pages: 212 DOI: 10.3390/books978-3-03842-743-8 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: General and Civil Engineering
Added to DOAB on : 2018-02-16 08:34:07
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This special feature issue has been initiated to celebrate the 25th anniversary of Optical Coherence Tomography (OCT). In OCT, broad bandwidth light is used in order to produce cross sectional images of turbid and translucent samples with high axial resolution (in the order of a few µm). The imaging speed of OCT can be as high as several millions of depth scans (A-scans) per second which allows for various applications in different fields. This special feature issue consists of three overview papers covering OCT angiography, polarization-sensitive OCT and dental applications of OCT. Additional applications and the latest developments in OCT are covered in nine research papers. The latest developments presented in this issue include magnetomotive OCT, resonant Doppler OCT, full field OCT, new segmentation algorithms and depth range extension. Applications of OCT are widely spread and range from quality control in tooth prostheses and coating thickness measurements in the automotive industry to the assessment of degradation of coatings and alveolar dynamics.

Pathophysiology and Imaging Diagnosis of Demyelinating Disorders

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ISBN: 9783038429432 9783038429449 Year: Pages: X, 168 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Neurology
Added to DOAB on : 2018-06-27 15:51:32
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Demyelinating disorders are chronic autoimmune disorders characterized by inflammation, demyelination, axonal degeneration, and neuronal loss. They have complex pathophysiology and diverse clinical presentations. The etiology of these disorders lies in the interaction between genetic and environmental factors. Due to the complexity in pathophysiology and presentation, diagnosis and treatment can be challenging. Advanced technology, including modern imaging techniques, as well as optical coherence tomography (OCT), enrich our understanding of the disease process, improve diagnostic accuracy, and may guide treatment decisions.

The chronic challenge - new vistas on long-term multisite contacts to the central nervous system

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889195084 Year: Pages: 161 DOI: 10.3389/978-2-88919-508-4 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2015-12-03 13:02:24
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Have you ever heard of a Hype-Cycle? It is a description that was put forward by an IT consultancy firm to describe certain phenomena that happen within the life cycle of new technology products. As Fenn and Raskino stated in their book (Fenn and Raskino 2008), a novel technology - a - “Technology Trigger” - gives rise to a steep increase in interest, leading to the “Peak of Inflated Expectations”. Following an accumulation of more detailed knowledge on the technology and its short-comings, the stake holders may need to traverse a “Trough of Disillusionment”, which is followed by a shallower “Slope of Enlightenment”, before finally reaching the “Plateau of Productivity”. In spite of the limitations and criticisms levied on this over-simplified description of a technology’s life-cycle, it is nonetheless able to describe well the situation we are all experiencing within the brain-machine-interfacing community. Our technology trigger was the development of batch-processed multisite neuronal interfaces based on silicon during the 1980s and 1990s (Sangler and Wise 1990, Campbell, Jones et al. 1991, Wise and Najafi 1991, Rousche and Normann 1992, Nordhausen, Maynard et al. 1996). This gave rise to a seemingly exponential growth of knowledge within the neurosciences, leading to the expectation of thought-controlled devices and prostheses for handicapped people in the very near future (Chapin, Moxon et al. 1999, Wessberg, Stambaugh et al. 2000, Chapin and Moxon 2001, Serruya, Hatsopoulos et al. 2002). Unfortunately, whereas significant steps towards artificial robotic limbs could have been implemented during the last decade (Johannes, Bigelow et al. 2011, Oung, Pohl et al. 2012, Belter, Segil et al. 2013), direct invasive intracortical interfacing was not quite able to keep up with these expectations. Insofar, we are currently facing the challenging, but tedious walk through the Trough of Disillusionment. Undoubtedly, more than two decades of intense research on brain-machine-interfaces (BMI’s) have produced a tremendous wealth of information towards the ultimate goal: a clinically useful cortical prosthesis. Unfortunately even today - after huge fiscal efforts - the goal seems almost to be as far away as it was when it was originally put forward. At the very least, we have to state that one of the main challenges towards a clinical useful BMI has not been sufficiently answered yet: regarding the long term – or even truly chronic – stability of the neural cortical interface, as well as the signals it has to provide over a significant fraction of a human’s lifespan. Even the recently demonstrated advances in BMI’s in both humans and non-human primates have to deal with a severe decay of spiking activity that occurs over weeks and months (Chestek, Gilja et al. 2011, Hochberg, Bacher et al. 2012, Collinger, Kryger et al. 2014, Nuyujukian, Kao et al. 2014, Stavisky, Kao et al. 2014, Wodlinger, Downey et al. 2014) and resolve to simplified features to keep a brain-derived communication channel open (Christie, Tat et al. 2014).

Optical Coherence Tomography guided Laser-Cochleostomy

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ISBN: 9783731503026 Year: Pages: VII, 180 p. DOI: 10.5445/KSP/1000044633 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Computer Science
Added to DOAB on : 2019-07-30 20:01:59
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Despite the high precision of laser, it remains challenging to control the laser-bone ablation without injuring the underlying critical structures. Providing an axial resolution on micrometre scale, OCT is a promising candidate for imaging microstructures beneath the bone surface and monitoring the ablation process. In this work, a bridge connecting these two technologies is established. A closed-loop control of laser-bone ablation under the monitoring with OCT has been successfully realised.

Optical MEMS

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ISBN: 9783039213030 / 9783039213047 Year: Pages: 172 DOI: 10.3390/books978-3-03921-304-7 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2019-12-09 11:49:15
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Optical microelectromechanical systems (MEMS), microoptoelectromechanical systems (MOEMS), or optical microsystems are devices or systems that interact with light through actuation or sensing at a micro- or millimeter scale. Optical MEMS have had enormous commercial success in projectors, displays, and fiberoptic communications. The best-known example is Texas Instruments’ digital micromirror devices (DMDs). The development of optical MEMS was impeded seriously by the Telecom Bubble in 2000. Fortunately, DMDs grew their market size even in that economy downturn. Meanwhile, in the last one and half decade, the optical MEMS market has been slowly but steadily recovering. During this time, the major technological change was the shift of thin-film polysilicon microstructures to single-crystal–silicon microsructures. Especially in the last few years, cloud data centers are demanding large-port optical cross connects (OXCs) and autonomous driving looks for miniature LiDAR, and virtual reality/augmented reality (VR/AR) demands tiny optical scanners. This is a new wave of opportunities for optical MEMS. Furthermore, several research institutes around the world have been developing MOEMS devices for extreme applications (very fine tailoring of light beam in terms of phase, intensity, or wavelength) and/or extreme environments (vacuum, cryogenic temperatures) for many years. Accordingly, this Special Issue seeks to showcase research papers, short communications, and review articles that focus on (1) novel design, fabrication, control, and modeling of optical MEMS devices based on all kinds of actuation/sensing mechanisms; and (2) new developments of applying optical MEMS devices of any kind in consumer electronics, optical communications, industry, biology, medicine, agriculture, physics, astronomy, space, or defense.

Keywords

scanning micromirror --- electromagnetic actuator --- angle sensor --- flame retardant 4 (FR4) --- variable optical attenuator (VOA) --- wavelength dependent loss (WDL) --- polarization dependent loss (PDL) --- micro-electro-mechanical systems (MEMS) --- tunable fiber laser --- echelle grating --- DMD chip --- MEMS scanning micromirror --- fringe projection --- laser stripe scanning --- quality map --- large reflection variations --- 3D measurement --- laser stripe width --- vibration noise --- MLSSP --- MEMS scanning mirror --- wavefront sensing --- digital micromirror device --- ocular aberrations --- dual-mode liquid-crystal (LC) device --- infrared Fabry–Perot (FP) filtering --- LC micro-lenses controlled electrically --- spectrometer --- infrared --- digital micromirror device (DMD) --- signal-to-noise ratio (SNR) --- stray light --- programmable spectral filter --- digital micromirror device --- optical switch --- microscanner --- input shaping --- open-loop control --- quasistatic actuation --- residual oscillation --- usable scan range --- higher-order modes --- resonant MEMS scanner --- electrostatic --- parametric resonance --- NIR fluorescence --- intraoperative microscope --- 2D Lissajous --- fluorescence confocal --- metasurface --- metalens --- field of view (FOV) --- achromatic --- Huygens’ metalens --- bio-optical imaging --- optical coherence tomography --- confocal --- two-photon --- spectrometer --- MEMS mirror --- electrothermal bimorph --- Cu/W bimorph --- electrothermal actuation --- reliability --- n/a

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