Academic literature on the topic 'In-lens detectors'
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Journal articles on the topic "In-lens detectors"
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Polkowska, Adelajda, Małgorzata Warmuzek, Julia Kalarus, Wojciech Polkowski, and Natalia Sobczak. "A comparison of various imaging modes in scanning electron microscopy during evaluation of selected Si/refractory sessile drop couples after wettability tests at ultra-high temperature." Prace Instytutu Odlewnictwa (Transactions of Foundry Research Institute) 57, no. 4 (2017): 337–44. https://doi.org/10.7356/iod.2017.35.
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In this work, FEI SciosTM field emission gun scanning electron microscope (FEG SEM) equipped with a unique combination of analytical and imaging detectors was utilized to examine structure and chemistry of selected Si/refractory couples. The couples were obtained in wettability tests performed by the sessile drop method coupled with contact heating of a refractory substrate (h-BN, SiC) at ultra-high temperature (up to 1750°C). The SEM observations were carried out on top-views of the couples, in order to evaluate surface and interfacial phenomena in Si/h-BN and Si/SiC systems. A full range of available detectors (e.g. classical Everhart-Thornley detector (ETD) or advanced in-lens detectors) working under various operation modes (secondary electrons (SE), backscattered electrons (BSE), a mixed mode), were used upon analyses in order to reveal specific features of obtained structures.
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Mikmeková, Šárka, Haruo Nakamichi, and Masayasu Nagoshi. "Contrast of positively charged oxide precipitate in out-lens, in-lens and in-column SE image." Microscopy 67, no. 1 (2017): 11–17. http://dx.doi.org/10.1093/jmicro/dfx117.
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Abstract Modern scanning electron microscopes are usually equipped with multiple detectors and enable simultaneous collection of two or even three secondary electron images. The secondary electrons become divided between the detectors in dependence on their initial kinetic energy and emission angle. In this study, sharing of the secondary electrons by out-lens, in-lens and in-column detectors has been systematically investigated. Energy filtering of the signal electrons is demonstrated by separation of the voltage and the topographical contrast in the micrographs obtained by out-lens and in-lens/in-column detectors. The presence of two detectors inside the electron column enables further filtering of the low kinetic energy secondary electrons, which results to unusual contrasts and phenomena. In this paper, inversion of the contrast sign between a positively charged oxide particle and conductive steel matrix (i.e. voltage contrast) in SE images collected under specific imaging conditions is demonstrated.
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Agemura, Toshihide, and Takashi Sekiguchi. "Collection efficiency and acceptance maps of electron detectors for understanding signal detection on modern scanning electron microscopy." Microscopy 67, no. 1 (2018): 18–29. http://dx.doi.org/10.1093/jmicro/dfx124.
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Abstract Collection efficiency and acceptance maps of typical detectors in modern scanning electron microscopes (SEMs) were investigated. Secondary and backscattered electron trajectories from a specimen to through-the-lens and under-the-lens detectors placed on an electron optical axis and an Everhart–Thornley detector mounted on a specimen chamber were simulated three-dimensionally. The acceptance maps were drawn as the relationship between the energy and angle of collected electrons under different working distances. The collection efficiency considering the detector sensitivity was also estimated for the various working distances. These data indicated that the acceptance maps and collection efficiency are keys to understand the detection mechanism and image contrast for each detector in the modern SEMs. Furthermore, the working distance is the dominant parameter because electron trajectories are drastically changed with the working distance.
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Tanrikulu, M. Yusuf. "Pixel level vacuum packaging for single layer microbolometer detectors with on pixel lens." Journal of Electrical Engineering 73, no. 3 (2022): 203–8. http://dx.doi.org/10.2478/jee-2022-0027.
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Abstract This paper presents a new approach for fabrication of single layer microbolometer detectors featuring pixel level vacuum packaging together with a lens on the pixel. The proposed lens structure can be used to increase the fill factor of the detector so that the pixel size can be decreased without decreasing the minimum feature size in the detector which is a problem in single layer microbolometers. The designs of the lens and the fabrication process of pixel level vacuum packaged microbolometer detector together with this lens are given in the framework of this study. The optical and mechanical simulations of the structure are performed. The radius of curvature of the lens is optimized to be 25 μm and it is shown that the condensing efficiency is 100% for 3 μm lens-detector distance. The deflection in the lens structure is found approximately as 0.8 nm in 1 atm environment pressure, showing that the proposed structure is durable. The proposed structure increases the fill factor to twice of the original value without decreasing the minimum feature size in the fabrication processes, resulting in the same amount of improvement in the performance of the detector. This approach can also be used to increase the yield and decrease the fabrication cost of single layer and also standard microbolometers with small pixel sizes, as it integrates the vacuum packaging in the fabrication steps.
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Zhang, Xinming, Xi Cen, Rijuta Ravichandran, Lauren A. Hughes, and Klaus van Benthem. "Simultaneous Scanning Electron Microscope Imaging of Topographical and Chemical Contrast Using In-Lens, In-Column, and Everhart–Thornley Detector Systems." Microscopy and Microanalysis 22, no. 3 (2016): 565–75. http://dx.doi.org/10.1017/s1431927616000751.
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AbstractThe scanning electron microscope provides a platform for subnanometer resolution characterization of material morphology with excellent topographic and chemical contrast dependent on the used detectors. For imaging applications, the predominantly utilized signals are secondary electrons (SEs) and backscattered electrons (BSEs) that are emitted from the sample surface. Recent advances in detector technology beyond the traditional Everhart–Thornley geometry have enabled the simultaneous acquisition and discrimination of SE and BSE signals. This study demonstrates the imaging capabilities of a recently introduced new detector system that consists of the combination of two in-lens (I-L) detectors and one in-column (I-C) detector. Coupled with biasing the sample stage to reduce electron–specimen interaction volumes, this trinity of detector geometry allows simultaneous acquisition of signals to distinguish chemical contrast from topographical changes of the sample, including the identification of surface contamination. The I-C detector provides 4× improved topography, whereas the I-L detector closest to the sample offers excellent simultaneous chemical contrast imaging while not limiting the minimization of working distance to obtain optimal lateral resolution. Imaging capabilities and contrast mechanisms for all three detectors are discussed quantitatively in direct comparison to each other and the conventional Everhart–Thornley detector.
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Minin, Oleg V., Jaime Calvo-Gallego, Yahya M. Meziani, and Igor V. Minin. "Improvement of an InfraRed Pyroelectric Detector Performances in THz Range Using the Terajet Effect." Applied Sciences 11, no. 15 (2021): 7011. http://dx.doi.org/10.3390/app11157011.
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An infrared (IR) pyroelectric detector was investigated for terahertz (THz) detection using the principle of the terajet effect, which focuses the beam beyond the diffraction limit. The terahertz beam was coupled to the detector’s optical window through a two-wavelength-dimension dielectric cubic particle-lens based on the terajet effect. We experimentally demonstrate an enhancement of about 6 dB in the sensitivity under excitation of 0.2 THz without degradation of the noise equivalent power value. The results show that the proposed method could be applied to increase the sensitivity of various commercial IR sensors for THz applications that do not require modification of the internal structure, and it may apply also to acoustics and plasmonic detectors.
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Aslan, Serhat Hasan, and Sinan Kaan Yerli. "Thin lens narcissus model in infrared lens design with cooled detectors." Applied Optics 61, no. 3 (2022): 728. http://dx.doi.org/10.1364/ao.447422.
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Ning, Yan, Shuo Zhang, Yao Hu, Qun Hao, and Xin Tang. "Simulation of Monolithically Integrated Meta-Lens with Colloidal Quantum Dot Infrared Detectors for Enhanced Absorption." Coatings 10, no. 12 (2020): 1218. http://dx.doi.org/10.3390/coatings10121218.
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Colloidal quantum dots (CQDs) have been intensively investigated over the past decades in various fields for both light detection and emission applications due to their advantages like low cost, large-scale production, and tunable spectral absorption. However, current infrared CQD detectors still suffer from one common problem, which is the low absorption rate limited by CQD film thickness. Here, we report a simulation study of CQD infrared detectors with monolithically integrated meta-lenses as light concentrators. The design of the meta-lens for 4 μm infrared was investigated and simulation results show that light intensity in the focused region is ~20 times higher. Full device stacks were also simulated, and results show that, with a meta-lens, high absorption of 80% can be achieved even when the electric area of the CQD detectors was decreased by a factor of 64. With higher absorption and a smaller detector area, the employment of meta-lenses as optical concentrators could possibly improve the detectivity by a factor of 32. Therefore, we believe that integration of CQD infrared detectors with meta-lenses could serve as a promising route towards high performance infrared optoelectronics.
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Erlandsen, Stanley L., Ya Chen, and Chris Frethem. "High Resolution Backscatter Electron (BSE) Imaging using the Autrata Modified YAG BSE Detector: Comparison of an In-lens Hitachi S-900 FESEM with the Below-the-Lens Hitachi S-4700 FESEM." Microscopy and Microanalysis 7, S2 (2001): 1046–47. http://dx.doi.org/10.1017/s1431927600031305.
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To obtain high resolution backscatter electron (BSE) images in field emission SEM (FESEM), one must consider selection of accelerating voltage, beam current, working distance between the specimen and the backscatter detector (in-lens or below-the-lens position for the specimen), the type of BSE detector, and the type of metal used to coat the specimen to improve conductivity and signal collection [1]. A new generation of below-the-lens FESEM have been tested for BSE imaging on biological samples, but no information exists on whether or not high resolution imaging is possible. Here we report the comparison of detection of a colloidal gold standard (6, 12, 18 nm) by high resolution BSE imaging using Autrata-modified YAG detectors in an in-lens FESEM and in a below-the-lens FESEM.Standards were prepared by mixing colloidal gold particles of 6 nm, 12 nm, and 18 nm. The gold particles were attached via poly-l-lysine to glass chips and coated with <1 nm Pt by ion beam sputtering.
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Veneklasen, Lee H. "An electron optical tool kit for transmission and surface electron microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 414–15. http://dx.doi.org/10.1017/s0424820100086374.
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This speculative discussion is offered in memory of Prof. Ben Siegel's fascination with the science of microscope instrumentation. It views the microscope configuration as a set of tools for creating observational opportunities. The central element is a condensor/objective lens in which the specimen is immersed, and along whose axis lie conjugate image and diffraction planes. An illumination system sets up beam conditions, in mode l1, forming a parallel beam, and Mode l2 forming a probe at the center of the lens. A projection system determines the plane within the objective that is magnified onto a recording detector surface. Projection mode P1, views the plane at the lens center, while projection mode P2 views the back focal or diffraction plane behind the lens. These two lens systems, along with apertures, scan coils, and detectors establish various modes of operation which make up the microscopist “tool kit”.
Books on the topic "In-lens detectors"
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Speller, Susannah. A Materials Science Guide to Superconductors. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780192858344.001.0001.
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Abstract Superconductors are amazing materials that capture the imagination with their seemingly magical properties that make it possible to levitate objects in mid-air and transport electricity for ‘free’. They can generate the vast magnetic fields needed to confine a nuclear fusion reaction ten time hotter than the surface of the sun, or bend the high energy proton beams that whizz around the Large Hadron Collider. Their utterly unique electromagnetic properties are exploited in the most sensitive detectors and are likely to be enabling technology for building practical quantum computers. This book explores the amazing variety of superconducting materials and the rich science behind optimising their performance for different applications. The central theme of materials science is communicated by explaining the importance of controlling everything from the atomic scale chemistry and bonding right up to the macroscopic scale of large machines. Along the way, key concepts are introduced in an accessible way and are linked to broader themes and applications beyond superconductivity in the ‘Wider View’ sections. The stand-alone ‘Under the Lens’ sections also provide a more in-depth and mathematical treatment to satisfy readers who want to challenge themselves.
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Lawrence, Amy. Ghost Channels. University Press of Mississippi, 2022. http://dx.doi.org/10.14325/mississippi/9781496838100.001.0001.
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Between 2004 and 2019, over seventy programs dealing with the paranormal have appeared on US television. “Paranormal reality” series (as distinct from scripted programs with paranormal subjects) combine the traits of the horror genre with the documentary style of reality television. Despite being widely derided, these programs have important things to tell us about America: economic and social pressures affecting the American middle class; the perceived failure of institutions; the persistence of racial and ethnic exclusion; and the way assumptions about what it means to be a man or a woman resist change and, occasionally, give way to new possibilities. These issues are explored not only through the lens of the paranormal (encounters with ghosts, demons, and other unexplainable phenomena) but through interactions with technology. Devices ranging from consumer-grade digital cameras to specialized temperature gauges, “night-vision” infra-red cameras and EMF detectors are used to identify the presence of -- and enable communication with -- hostile or friendly spirits, thus validating the otherwise inexplicable experiences of ordinary people. Questions about technology’s reliability, its association with science and reason and its usefulness to “average” Americans, expand to include television itself as the medium is interrogated in a variety of ways.In-depth analyses of over thirty paranormal television series provide insight into the paranormal reality television genre, its development and place in cable television, and reveals the things Americans fear in the first two decades of the twenty-first century.
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Wright, A. G. The optical interface to PMTs. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780199565092.003.0003.
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The optical interface between a light source and a detector is important. In most practical realizations the aim should be to collect the maximum light possible. Lens systems seldom do this efficiently, especially where the light source is diffuse. Underlying any attempt at concentrating or guiding light is subject to a fundamental limitation referred to as étendue (phase space cannot be squeezed). Light collection from small volume scintillators of high refractive index may approach 50 %, while collection from large-area scintillators is typically less than a few per cent. Incorporation of wavelength-shifting light guides and fibres leads to enhanced performance. Efficiency measurements by the author in terms of photoelectrons per keV are presented for selected configurations. Optical recycling derived from total internal reflection provides enhancement in effective quantum efficiency by a factor of up to 10. Concepts such as escape cones, adiabatic light guides, and trapped light are covered in detail.
Book chapters on the topic "In-lens detectors"
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Orekhov, Feodor, and Oleg Gradov. "Tensoresistor-Based Microfluidics and Telemetric Strain-Gauge Lens-Less Detectors as Specialized Labs-on-a-Chip for Soil Mechanics and Foundation Monitoring." In Lecture Notes in Civil Engineering. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-83917-8_34.
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Neto Andrea, Llombart Juan Núria, Baselmans Jochem J.A., Baryshev Andrey, and Yates Stephen. "THz Leaky Lens Antenna integrated with Kinetic Inductance Detectors." In Pulsed Electromagnetic Fields: Their Potentialities, Computation and Evaluation. IOS Press, 2013. https://doi.org/10.3233/978-1-61499-230-1-121.
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This contribution presents the fabrication and measurements of the leaky lens antenna integrated with a cryogenically cooled Kinetic Inductance Detector, in order to achieve an ultra sensitive THz receivers over a bandwidth ranging from 0.15GHz to 1.5 THz. The system has been manufactured and characterized in terms of power efficiency, and radiation pattern properties. The agreement between the expectations and the measurements is excellent already at this first attempt. These measurements demonstrate the manufacturability and repeatability at THz frequencies of the properties of the leaky lens antenna concept.
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Wolken, Jerome J. "Invertebrate Eyes: Variations in Structural Design for Vision." In Light Detectors, Photoreceptors, and Imaging Systems in Nature. Oxford University PressNew York, NY, 1995. http://dx.doi.org/10.1093/oso/9780195050028.003.0012.
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Abstract Invertebrates are the most numerous and diverse among all animal groups, and their eye structures and optical and photoreceptor systems are equally diverse. Image forming compound eyes evolved in arthropods (insects, arachnids, and crustacea) and are generally restricted to them. Compound eyes are structured of eye facets, ommatidia (Figure 12.1). The number of ommatidia varies from only a few in certain species of ants to more than 2,000 in the dragonfly. Each ommatidium is a complete eye, containing two functional systems: the dioptric, or optical, system and the photoreceptor rhabdom system. The optical system is the corneal lens and the crystalline cone that transmit the image on to the rhabdom.
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Chipman, Ariel D. "Sensory systems." In Organismic Animal Biology. Oxford University PressOxford, 2024. http://dx.doi.org/10.1093/oso/9780192893581.003.0012.
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Abstract The world is teeming with information that can be collected by an organism and used to improve its chance of survival. Different sources of information are known as sensory modalities. Sense organs in diverse animals are optimized for detecting and interpreting different sensory modalities. The interpretation of sensory information is done by the nervous system, which is composed of neurons and a range of other supporting cells. The most ancient and most common sensory modality is chemoreception—the ability to detect specific molecules based on dedicated receptors situated on chemosensory cells. Mechanical reception includes a range of organs that give information about physical-mechanical aspects of the world. This includes touch receptors, gravity and motion detectors, flow detectors, pressure detectors, and others. Photoreception gives many organisms, including ourselves, the most detailed and nuanced information about the world. Photoreceptor organs range from simple light-detecting patches, to complex eyes with a movable lens and a large hemispherical retina. We can trace an evolutionary trajectory linking the different types of photoreceptor organs. Additional sensory modalities include detection of electro-magnetic fields, a sense of self, and the perception of pain.
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"DIY Cameras: Some Principles." In Lo-Fi Photography. Royal Society of Chemistry, 2024. http://dx.doi.org/10.1039/bk9781839169311-00213.
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Common principals are reviewed for homemade cameras designed for long-exposure photographs, including pinhole cameras and those meant to be used with detectors of very-low sensitivity. Large-format cameras with either fixed focus or a view screen arrangement are emphasized. Some suitable but inexpensive options for lenses are described, but much attention is spent on the use of simple double-convex glass lenses, such as might be found in an inexpensive hand lens. The distortions, aberrations, and field curvature of a simple lens are illustrated, and how this might be used to advantage for selective focus of suitable subjects. Three designs of simple cameras are illustrated—a simple fixed-focus box camera, a simple view camera, and a box camera with a focal plane that can be interactively curved in one dimension.
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Krishnan, Kannan M. "Scanning Electron Microscopy." In Principles of Materials Characterization and Metrology. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198830252.003.0010.
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A scanning electron microscope (SEM) focuses an electron beam to a sharp probe, with its diameter, which depends on the acceleration voltage and the aberration coefficients of the probe-forming lens, determining SEM resolution. This electron beam is scanned over the specimen and signals arising from a variety of beam-specimen interactions are recorded to form images using different detectors positioned in the specimen chamber. Secondary electrons, detected with the Everton-Thornley detector, reveal the topography and electrical properties; back-scattered electrons provide information about the average atomic number and local crystallography of the specimen. Ferromagnetic materials alter the trajectory of secondary (Type I) and back-scattered (Type II) electrons to provide magnetic contrast. The magnetic polarization of the secondary electrons can also be analyzed directly (SEMPA) to image domains. The electron beam also excites characteristic X-rays for chemical microanalysis. Luminescent specimens produce light (Cathodoluminescence); these photons provide information on the electronic structure, particularly the defect states, of the specimen. Environmental SEMs, with differential pumping, image the specimen in a gaseous environment and/or under hydration for biological materials. A SEM combined with a focused ion beam (FIB) column is used for nano-fabrication, including preparation of electron-transparent TEM specimens.
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Solymar, Laszlo, Donald Walsh, and Richard Syms. "Artificial materials or metamaterials." In Electrical Properties of Materials, 11th Edition, 11th ed. Oxford University PressOxford, 2024. http://dx.doi.org/10.1093/9780198921004.003.0015.
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Abstract Describes new artificial materials generally operating in the electromagnetic domain and based either on structured dielectrics (photonic bandgap materials), or combinations of structured dielectrics and metals (metamaterials). Discusses the dielectric properties of arrays of wires and the magnetic properties of arrays of resonant loops such as split ring resonators. Introduces the idea of an effective permittivity and permeability at RF or optical frequency resulting from these ararngements and discusses the new effects that can arise when both are negative (and the refractive index is also negative). Considers applications in the form of photonic bandgap fibres (which can confine light inside a hollow core), the perfect lens (whose resolution can exceed the diffraction limit) and detectors for magnetic resonance imaging (whose periodic construction can provide patient safety in internal imaging).
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Glaeser, Robert M., Kenneth Downing, David DeRosier, Wah Chiu, and Joachim Frank. "Instrumentation and Experimental Techniques." In Electron Crystallography Of Biological Macromolecules. Oxford University PressNew York, NY, 2007. http://dx.doi.org/10.1093/oso/9780195088717.003.0005.
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Abstract In this chapter we first present a general overview (section 5.2) of the instrumental design of an electron microscope. This is followed in section 5.3 by more specific and detailed descriptions of several key components such as the electron gun, the condenser lens system, the objective lens, and the projector lens system. Along with this we develop some of the practical aspects that are related to optical coherence and alignment of the illumination, as well as the effects that these factors have on the contrast transfer function. These are topics that we discussed previously from a more theoretical perspective in section 3.9. In section 5.4 we move on to describe options that are available in the design of specimen stages, emphasizing the need for low specimen temperatures and explaining the relative advantages of top-entry and side-entry stage designs. Section 5.5 deals with the main parameters that are important in the various types of detectors used for recording both images and electron diffraction patterns. Two further sections then discuss some of the experimental details of how high-resolution images are recorded for beam-sensitive specimens. The first section on experimental image collection, section 5.6, addresses the need to record images with very low electron exposures, thus ensuring that the specimen receives only a negligible exposure before the data collection begins. The second section on experimental image collection, section 5.7, discusses the “spot-scan” exposure method, in which only a small area of the whole field of view is illuminated by the electron beam at any one time. Section 5.8 then concludes this chapter with a description of precautions that must be taken in order to avoid image artifacts associated with specimen charging.
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Manikandakumar, M. "Smart Cataract Detector." In Advances in Healthcare Information Systems and Administration. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-2581-4.ch011.
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Eyes react to light. Cataract, a common eye disease, clouds the lens of the eye, which decreases vision and can cause blindness. It can be in one or both eyes. The most major cause of cataract is ageing. Cataract also can be found in children and can occur due to eye injuries and inflammation. As mobile technology emerges to a greater extent, designing an application would help people perform a self check-up without meeting the doctors in person, thus saving time and cost. The pre-diagnosis of cataracts is costly for poor people. Time taken by the machine to detect cataract is greater, so the doctor can't attend as many patients. A cheap, reliable mobile application that helps diagnose cataract would cut cost and simplify diagnosis. This chapter proposes the development of smart phone application to detect the presence of cataract using image processing techniques.
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Grigorieva, Elena, Oleg Gradov, Margaret Gradova, and Irina Maklakova. "Towards Multi-Angle Multispectral Optical 3D Porometry and Lens-Less Porometry of Civil Engineering Composites and Geocomposites Including Biodegradable Ones." In Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220857.
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In this work we demonstrate the images of multi-angle porometry of civil engineering composites with the static pores. We also demonstrate an example of the application of multi-angle scanning methods where each pore visualization angle corresponds to the certain time moment. The light source can be either incoherent or coherent, which determines the data interpretation principles and data processing algorithms. The light detector can be either optical microscopic (with lenses) or lens-less, that is, either a microscope with an objective or a lens-less one, especially a holographic lens-less microscope. The latter is by definition compatible with multi-angle microporometry. The data on reconstruction of the surface texture of a complex pore using an incoherent light source and the Sobel-Feldman operator (Stanford Artificial Intelligence Laboratory (SAIL)) is presented.
Conference papers on the topic "In-lens detectors"
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Grzyb, J., R. Al Hadi, and U. R. Pfeiffer. "Lens-integrated on-chip antennas for THz direct detectors in SiGe HBT technology." In 2013 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting. IEEE, 2013. http://dx.doi.org/10.1109/aps.2013.6711791.
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Fisher, Donald. "Design of high-speed infrared lenses using conic surfaces." In International Optical Design Conference. Optica Publishing Group, 1998. http://dx.doi.org/10.1364/iodc.1998.lfa.5.
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This paper presents the optical design of high resolution lens systems used with uncooled infrared (IR) detector arrays. As these lower cost arrays proliferate, the need arises for lenses that are faster (i.e. have smaller f/numbers), less expensive, and out perform previously designed lenses for cooled detectors. Many techniques have been explored to increase the performance of IR lenses, however, they do not reduce the complexity or number of surfaces in the optical system [1]. One method of reducing the number of elements and weight while increasing the optical performance is to employ conic surfaces in addition to spherical surfaces.
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Kearney, Ian, and Mark Dipsey. "Trends in Discrete Power MOSFET and Power System In-Package Fault Isolation." In ISTFA 2017. ASM International, 2017. http://dx.doi.org/10.31399/asm.cp.istfa2017p0419.
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Abstract Photoluminescence, defect-band emission, and Lock-in Infrared Thermography (LIT) generally enable the correlation of multi-crystalline silicon defect types. Long Wavelength Infrared (LWIR) thermal imaging has traditionally seen limited application in failure analysis. LWIR cameras are typically uncooled systems using a microbolometer Focal Plane Arrays (FPA) commonly used in industrial IR applications, although cooled LWIR cameras using Mercury Cadmium Tellurium (MCT) detectors exists as well. On the contrary, the majority of the MWIR cameras require cooling, using either liquid nitrogen or a Stirling cycle cooler. Cooling to approximately −196 °C (77 K), offers excellent thermal resolution, but it may restrict the span of applications to controlled environments. Recent developments in LWIR uncooled and unstabilized micro-bolometer technology combined with microscopic IR lens design advancements are presented as an alternative solution for viable low-level leakage (LLL) defect localization and circuit characterization. The 30 micron pitch amorphous silicon type detector used in these analyses, rather than vanadium oxide (VOx), has sensitivity less than 50mK at 25C. Case studies reported demonstrate LWIR enhanced package-level and die-level defect localization contrasted with other quantum and thermal detectors in localization systems.
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Awwal, Abdul Ahad S., Hadi Kaftan, L. Li, and Jamal U. Ahmed. "Surface roughness measurement using an inexpensive laser diode source." In OSA Annual Meeting. Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.thmm51.
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Testing the surface texture of a machined object, thin films, soft materials requires a noncontact, high precision surface measuring system. The use of the optical signal for surface profile generation gives advantage over a mechanical stylus system because of its nondestructive nature.1 In this method, a laser beam of predetermined Gaussian profile2 is focused via a lens into the measuring surface. The reflected beam is separated by a polarizing prism from the incoming beam and taken to a quadrant detector. When the beam is focused all detector segments receive equal amounts of light, but when the surface moves in or out of focus it creates an imbalance of light falling on the quad detectors. The difference of the detector signals acts as an error signal that provides a direct measure of the profile of the surface.
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V.L., Kasyutich. "Laser diode refractive index detection in capillary." In Laser Applications to Chemical and Environmental Analysis. Optica Publishing Group, 1998. http://dx.doi.org/10.1364/lacea.1998.lmc.2.
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A cylindrical sample cell (capillary) is used widely in photothermal lens spectroscopy [1-4], refractive index (RI) detectors for microbore liquid chromatography [5,6] and capillary electrophoresis [7-9], in analysis of fluids [10,11]. An inner diameter of the capillary can be varied from hundreds down to tens microns and laser sources are appreciable for probing of the samples in the capillary.
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Wilkerson, Gary W., and Vinson Huegele. "The optical design of a system using a Fresnel lens that gathers light for a solar concentrator and that feeds into solar alignment optics." In International Optical Design Conference. Optica Publishing Group, 1998. http://dx.doi.org/10.1364/iodc.1998.lwb.5.
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The Marshall Space Flight Center (MSFC) has been developing a space deployable, lightweight membrane concentrator to focus solar energy into a solar furnace. For an inner surface, this furnace has a cylindrical heat exchanger cavity coaligned to the optical axis; the furnace warms gas to propel the spacecraft. The membrane concentrator is planned as an F/1.7 Fresnel lens with over a one meter diameter. This large membrane is made from polyimide and is 0.076 mm (0.003 in.) thick; it has the Fresnel grooves cast into it. The Fresnel lens also possesses a narrow annular zone that focuses a reference beam toward four detectors that keep the optical system aligned to the sun. The solar concentrator system has a super fast paraboloid reflector near the lens focus and immediately adjacent to the cylindrical exchanger cavity. The paraboloid collects the wide bandwidth and some of the solar energy scattered by the Fresnel lens. Finally, the paraboloid feeds the light into the cylinder.
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Vu, T. Q., and C. S. Tsai. "GaAs Waveguide Microlenses and Lens Arrays with Applications to Data Processing and Computing*." In Optical Computing. Optica Publishing Group, 1989. http://dx.doi.org/10.1364/optcomp.1989.tui8.
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Waveguide lenses are among the essential components in construction of integrated optic modules or circuits for data processing and computing. For this purpose, various types of waveguide lens have been fabricated in LiNbO3 substrate. These lens types include Luneburg, geodesic, index refraction via TIPE or two layers construction, chirp grating, and Fresnel. Some of these lens types have been utilized to construct RF spectrum analyzers, correlators,(1,2,3) and computers.(4,5,6) Despite the various successes with such LiNbO3-based modules they have only been developed into hybrid integrated optic (IO) modules due to lack of technology for integration of lasers, detectors, and associated electronic circuits in the same substrate. In contrast, the GaAs-based substrate provides the capability for monolithic integration of all passive and active components. However, the material constraints such as a very high refractive index and high brittleness, and the relatively small reduction in refractive index in Ga1−xAlxAs for a desirable fractional composition x have prevented any lens type from being fabricated in GaAs waveguide heretofore. We have most recently utilized ion-milling technique to fabricate waveguide lenses of high efficiency and diffraction-limited focal spot size in GaAs. In this paper, design, fabrication, and measured performances of single microlenses and microlens arrays of the analog Fresnel and chirp grating types as well as hybrid combination of the two are presented. IO modules that incorporate such waveguide lenses and acoustooptic and electrooptic Bragg modulators in channel-planar composite waveguides are also being constructed. The measured performances of such modules with applications to data processing and computing will also be reported.
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Elliott, C. T., and I. M. Baker. "Infrared detector research and development in the United Kingdom." In The European Conference on Lasers and Electro-Optics. Optica Publishing Group, 1994. http://dx.doi.org/10.1364/cleo_europe.1994.ctun3.
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The current trends in infrared detectors are principally towards larger electronically addressed arrays and towards reduced cryogenic cooling requirements. In the UK the research activities have been mainly on hybrids of CdxHg1–xTe (CMT) and of ferroelectric materials on silicon. Large two-dimensional arrays and long linear arrays of CMT are presently fabricated in LPE material by the “loophole" interconnect technology. Results are presented for linear formats up to 1024 elements and for two-dimensional arrays of 128 × 128 elements. It is anticipated that loophole technology will be supplemented at some time in the future by a technology using MOVPE-grown heterostructures, so that the operating temperature of photon detectors can be increased by means of optical concentration or non-equilibrium operation. The former is described in terms of an individual field lens concentrator and the latter is illustrated by recent results on CMT and InSb/In1–x AlxSb heterostructures. The heterostructure devices, as well as producing significantly improved RoA, exhibit strong negative resistance effects at temperatures from 190 K upwards. Recent results of 128 × 256 arrays of uncooled ferroelectric hybrids fabricated by solder-bump bonding show very promising performance.
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Huang, Chingchu, B. Keith Jenkins, and Charles B. Kuznia. "Weighted Space-Variant Local Interconnections Based on Micro-Optic Components: Crosstalk Analysis and Reduction." In Optical Computing. Optica Publishing Group, 1995. http://dx.doi.org/10.1364/optcomp.1995.othb3.
Full textAbstract:
(1) Introduction. The use of diffractive optical elements (DOE’s) and microlens arrays in optical interconnection systems can potentially provide high throughputs and small system volumes, using components that are amenable to automated design and mass production techniques. This paper considers fixed-weight neural network interconnections based on such components, and focuses on the realm of small system volumes and short propagation lengths (~1 mm) with potential for cascading into a compact, multilayer free-space system. We consider the space-variant interconnection system of Fig. 1, and achieve short propagation lengths by restricting each fanout pattern to a local neighborhood. The system uses an array of NxN sub-DOE's at the input plane to connect to an array of NxN detectors at the output plane. For this locally connected neural network interconnection, each sub-DOE stores one weighted fanout pattern that connects to MxM nearest neighbors in the output plane. The beam incident on each sub-DOE comes from a modulator or an emitter (not shown), which represents an interconnection input node (e.g., an output of a neuron unit). The optics of the interconnection system provides a Fourier transform (in magnitude) from each sub-DOE to the detector array, which serves as a set of neuron unit inputs. We constrain the sub-DOE spacing to be equal to the detector spacing to allow for use in multilayer systems. A globally connected space-variant system can be realized similarly by replacing the microlens array with a bulk lens and letting each input node connect to all output plane detectors [1,2]. The minimum propagation distance and system volume can be shown to be approximately proportional to M and N^M for the local system, and N and A3 for the global system, respectively. While the local system can be used in a smaller volume, its crosstalk levels can be high due to reconstruction noise (e.g., diffraction orders outside of the local fanout neighborhood) of each sub-DOE. In this paper, we describe a crosstalk reduction method enabled by varying the mapping from reconstructed spot locations to detector locations. Several novel DOE designs for, and simulations of, local fixed-weight neural network interconnections are evaluated as a test of this method.
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Harrolle, Jennifer, Michael Bass, and Madhu Acharekar. "A Laser and Fiber Optics Based, Passive, Differential System to Measure the Optical Properties of Liquids and Gases." In Laser Applications to Chemical and Environmental Analysis. Optica Publishing Group, 1998. http://dx.doi.org/10.1364/lacea.1998.lmc.3.
Full textAbstract:
It is often desirable or necessary to measure the optical properties of liquids and gases in remote locations. Examples include measurement of the absorption and scattering of ocean water or the monitoring of liquid quality during manufacturing large volumes of product. In such cases it may be inconvenient or dangerous or both to retrieve samples for off line measurement and it may be too risky or expensive to submerse the appropriate conventional instruments. In this paper a device is described in which laser light is delivered to a remote sample of liquid by a fiber optic and collected through another fiber optic enabling measurement of optical absorption, scattering and also, if fluorescing materials are present, their emissions. The device is shown schematically in Fig. 1. In a safe location, in a console, are all the operator controls, laser light sources, beam handling and control optics and electronics to generate the light, deliver it to the send fiber and sense light returned by the appropriate collector lens return fiber combination. At the distal end of the send fiber a lens collimates the beam for transmission through the medium. A second lens collects the transmitted or scattered light and focuses it into a return fiber. Detectors and electronics in the console record and process this data.