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1
Richter, Hilmar H., Michael Harr, Peter Dinges, Heribert Krüger, Alexandra Todisco y Bernd Zimmermann. "Development and Manufacture of a Linear 16-Pixel FIR Array—The PACS Module". Journal of Microelectronics and Electronic Packaging 4, n.º 4 (1 de octubre de 2007): 136–44. http://dx.doi.org/10.4071/1551-4897-4.4.136.
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The high- and low-stressed photodetector array camera and spectrometer (PACS) modules (linear 16-pixel arrays) are the basic constituents of the 16 × 25 pixel far-infrared (57–220 μm) PACS cameras aboard the Herschel satellite. The essentials for the stress application and the pixel stacking technique originate from detectors aboard the Infrared Space Observatory (ISO, 1995–1998) and for the field imaging far infrared line spectrometer (FIFI-LS) aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA). To meet the mass budget of the cameras and provide the required high tensile strength, the only usable material for the module body turned out to be an aluminum alloy (AL 7075 T651). Especially challenging was the tight thermal budget for the PACS modules. Compared to FIFI-LS, in the case of the PACS module the heat dissipation from the front end electronics (FEE) and harness substrates at about 4 K to the module body containing the pixel stack at about 2 K had to be reduced drastically. A genuine suspension concept and packaging for the respective substrates was developed and successfully applied, allowing reliable electrical wiring from the harness over the FEE on to the pixels. The FEE with the cryogenic readout electronics (CRE) is contributed by the Interuniversity Microelectronics Centre (IMEC).
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Sturm, James C. "Advanced Column-IV Epitaxial Materials for Silicon-Based Optoelectronics". MRS Bulletin 23, n.º 4 (abril de 1998): 60–64. http://dx.doi.org/10.1557/s0883769400030281.
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Over the past decade or so, research in silicon-based heterostructures has evolved from a few seminal publications on the growth and physical properties of Si1−xGex heteroepitaxial layers to a technology currently entering large-scale commercial production for heterojunction bipolar transistors (HBTs). During this period, extensive work has taken place on the optoelectronic applications of Si/Si1−x Gex such as 1.3–1.55 μam detectors for optical communication, 2–12-μm infrared detectors for two-dimensional (2D) focal plane arrays for night vision and thermal imaging, and infrared emitters for chip-to-chip optical communication as well as waveguiding and modulators. The overall goal of this work has been to merge optoelectronic functionality with the very large-scale-integration and electronic signal processing capabilities of silicon to create a silicon-based “superchip.”
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Singh, Anand y Ravinder Pal. "Infrared Avalanche Photodiode Detectors". Defence Science Journal 67, n.º 2 (14 de marzo de 2017): 159. http://dx.doi.org/10.14429/dsj.67.11183.
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This study presents on the design, fabrication and characteristics of HgCdTe mid-wave infrared avalanche photodiode (MWIR APD). The gain of 800 at - 8 V bias is measured in n+-ν-p+ detector array with pitch size of 30 μm. The gain independent bandwidth of 6 MHz is achieved in the fabricated device. This paper also covers the status of HgCdTe and III-V material based IR-APD technology. These APDs having high internal gain and bandwidth are suitable for the detection of attenuated optical signals such as in the battle field conditions/long range imaging in defence and space applications. It provides a combined solution for both detection and amplification if the detector receives a very weak optical signal. HgCdTe based APDs provide high avalanche gain with low excess noise, high quantum efficiency, low dark current and fast response time.
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Bashir, Muhammad Salman y Mohamed-Slim Alouini. "Free-Space Optical MISO Communications With an Array of Detectors". IEEE Open Journal of the Communications Society 1 (2020): 1765–80. http://dx.doi.org/10.1109/ojcoms.2020.3035600.
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Kulchitsky, N. A., A. V. Naumov y V. V. Startsev. "Development Trends of Infrared Focal Plane Array Detectors". Nano- i Mikrosistemnaya Tehnika 22, n.º 9 (29 de diciembre de 2020): 500–510. http://dx.doi.org/10.17587/nmst.22.500-510.
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Since its inception, the market for infrared (IR) thermal imaging equipment has grown, primarily, due to its military applications. Today, the military sector still provides some growth for the market, but its development paradigm has changed. Now the main growth in the market is provided by the sectors of civil and medical thermography, security and fire surveillance, personal night vision systems and local security niches (municipal, private, etc.). The devices using thermal imagers make it possible to detect in conditions of poor visibility, to detect people with high temperature in the crowd. In the last decade, a number of new directions and trends have been outlined in infrared photoelectronics. They are associated with increasing the resolution of systems, improving methods for recording ultra-weak optical signals, creating high-speed and multispectral systems, forming infrared 3D images According to forecast of Maxtech International (USA) and today's estimates of the authors, the market for infrared systems (civil and military) amounted to 10.5 billion dollars in 2017, and could reach 20 billion dollars by 2025. Due to the pandemic, we have restated the Maxtech International's forecasts upwardly for the medium term.
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Treado, Patrick J., Ira W. Levin y E. Neil Lewis. "Indium Antimonide (InSb) Focal Plane Array (FPA) Detection for Near-Infrared Imaging Microscopy". Applied Spectroscopy 48, n.º 5 (mayo de 1994): 607–15. http://dx.doi.org/10.1366/0003702944924899.
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Near-infrared spectroscopy is a sensitive, noninvasive method for chemical analyses, and its integration with imaging technologies represents a potent tool for the study of a wide range of materials. In this communication the use of an indium antimonide (InSb) multichannel imaging detector for near-infrared absorption spectroscopic microscopy is described. In particular, a 128 × 128 pixel InSb staring array camera has been combined with a refractive optical microscope and an acousto-optic tunable filter (AOTF) to display chemically discriminative, spatially resolved, vibrational spectroscopic images of biological and polymeric systems. AOTFs are computer-controlled bandpass filters that provide high speed, random wavelength access, wide spectral coverage, and high spectral resolution. Although AOTFs inherently have a wide range of spectroscopic applications, we apply this technology to NIR absorption microscopy between 1 and 2.5 μm. The spectral interval is well matched to the optical characteristics of both the NIR refractive microscope and the AOTF, thereby providing near-diffraction-limited performance with a practical spatial resolution of 1 to 2 μm. Design principles of this novel instrumentation and representative applications of the technique are presented for various model systems.
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Tinbergen, J. "Array Polarimetry and Optical-Differencing Photometry". Symposium - International Astronomical Union 167 (1995): 197–205. http://dx.doi.org/10.1017/s0074180900056448.
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Array detectors have improved the efficiency of optical polarimetry sufficiently for this technique to become part of the standard arsenal of observational facilities. However, we could gain even more: spatially-differentiating photometry can be implemented as an option of array Polarimeters and low-noise, high-frame-rate array detectors will allow extremely high precision both in polarimetry and in such differentiating photometry. The latter would be valuable for analyzing many kinds of optical or infrared images of very low contrast; the essence of the technique is to use optical (and extremely stable) means to produce the spatial derivative of the flux image, in the form of a polarization image which is then presented to a “standard” array polarimeter. The polarimeter should incorporate a polarization modulator of sufficient quality for the photometric application in mind. If developed properly, using a state-of-the-art array detector and the most sensitive type of polarization modulator (stress-birefringence), optical differencing will allow levels of relative photometric precision not otherwise obtainable. With the optical differencing option taken out of the beam, the same instrument can be used for high-quality polarimetry.
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D'Odorico, Sandro. "Array Detectors and Instruments for the ESO VLT". Symposium - International Astronomical Union 167 (1995): 9–17. http://dx.doi.org/10.1017/s0074180900056217.
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Two-D array detectors are one of the key components of the instruments being built for the four ESO 8-m telescopes, the VLT project. Three optical and two infrared instruments are under construction. One faint object imager and multi-slit spectrograph to operate in the spectral region 350–1000 nm (acronym FORS) is based on a 20482 high-efficiency CCD. A two-channel echelle spectrograph to work in the 300–1000 nm region (UVRS) is built around a mosaic of 20482, 15 μm CCDs. A multifiber, new spectrograph is based on a 4096 × 2048, 16 μm CCD. The two infrared high-resolution instruments, one imager/long-slit spectrometer (ISAAC) and one high-resolution camera are designed to work with adaptive optics and in the speckle mode (CONICA). Both are designed to incorporate IR arrays up to a format of 10242 and will work in the spectral region of 1–5 μm. The main properties of the instruments and of detectors are presented and their close interdependence is illustrated.
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Zhang, Tong, Chun Lin, Honglei Chen, Changhong Sun, Jiamu Lin y Xi Wang. "MTF measurement and analysis of linear array HgCdTe infrared detectors". Infrared Physics & Technology 88 (enero de 2018): 123–27. http://dx.doi.org/10.1016/j.infrared.2017.11.010.
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Jain, Ankur y Amiya Biswas. "Parasitic Flux Analysis of Cooled Infrared Detectors for Space Applications". Defence Science Journal 67, n.º 2 (14 de marzo de 2017): 193. http://dx.doi.org/10.14429/dsj.67.11180.
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An infrared imager measures radiations emitted by an object in specified spectral bands to determine change in object’s characteristics over a period of time. A typical infrared imager consists of focusing optics and a cryogenically cooled two-dimensional infrared detector array mounted on the cold tip of an active micro-cooler vacuum sealed with an optical window, typically known as integrated detector cooler assembly (IDCA). Detection of feeble radiant flux from the intended target in a narrow spectral band requires a highly sensitive low noise sensor array with high well capacity. However, in practical applications the performance of an infrared imager is limited by the parasitic thermal emissions from optical elements and emissions from IDCA components like vacuum window, Dewar walls which are generally kept at ambient temperature. To optimise the performance of imager it becomes imperative to estimate these parasitic fluxes and take corrective actions to minimise their effects. This paper explains an analytical model developed to estimate parasitic fluxes generated from different components of a long wave infrared imager. Validation of the developed model was carried out by simulations in ZEMAX optical design software using ray trace method after analytical computations in MATLAB.
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ROGALSKI, A. "QUANTUM WELL INFRARED PHOTOCONDUCTORS IN INFRARED DETECTORS TECHNOLOGY". International Journal of High Speed Electronics and Systems 12, n.º 03 (septiembre de 2002): 593–658. http://dx.doi.org/10.1142/s0129156402001654.
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Investigations of the performance of quantum well infrared photodetectors (QWIPs) as compared to other types of semiconductor infrared (IR) detectors are presented. In comparative studies both photon and thermal detectors are considered. More attention is paid to photon detectors and between them we can distinguish: HgCdTe photodiodes, InSb photodiodes, Schottky barrier photoemissive detectors, and doped silicon detectors. Special attention has been paid to competitive technologies in long wavelength IR (LWIR) and very LWIR (VLWIR) spectral ranges with emphasis on the material properties, device structure, and their impact on FPA performance. The potential performance of different materials as infrared detectors is examined utilizing the α/G ratio, where α is the absorption coefficient and G is the thermal generation. From the discussion results, LWIR QWIP cannot compete with HgCdTe photodiode as the single device especially at higher temperature operation(> 70 K) due to fundamental limitations associated with intersubband transitions. However, the advantage of HgCdTe is less distinct in the temperature range below 50 K due to problems involved in the HgCdTe material (p-type doping, Shockley–Read recombination, trap-assisted tunneling, surface and interface instabilities). Even though the QWIP is a photoconductor, several its properties such as high impedance, fast response time, long integration time, and low power consumption, well comply with requirements for large FPAs fabrication. Due to the high material quality at low temperature, QWIP has potential advantages over HgCdTe for VLWIR FPA applications in terms of the array size, uniformity, yield and cost of the systems. Both HgCdTe photodiodes and quantum well infrared photodetectors offer multicolor capability in the MWIR and LWIR range. Powerful possibilities of QWIP technology are connected with VLWIR FPA applications and with multicolor detection. QWIP FPAs combine the advantages of PtSi Schottky barrier arrays (high uniformity, high yield, radiation hardness, large arrays, lower cost) with the advantages of HgCdTe (high quantum efficiency and long wavelength response).
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Bellei, Francesco, Alyssa P. Cartwright, Adam N. McCaughan, Andrew E. Dane, Faraz Najafi, Qingyuan Zhao y Karl K. Berggren. "Free-space-coupled superconducting nanowire single-photon detectors for infrared optical communications". Optics Express 24, n.º 4 (9 de febrero de 2016): 3248. http://dx.doi.org/10.1364/oe.24.003248.
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Zhang, Shuo, Yao Hu y Qun Hao. "Advances of Sensitive Infrared Detectors with HgTe Colloidal Quantum Dots". Coatings 10, n.º 8 (4 de agosto de 2020): 760. http://dx.doi.org/10.3390/coatings10080760.
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The application of infrared detectors based on epitaxially grown semiconductors such as HgCdTe, InSb and InGaAs is limited by their high cost and difficulty in raising operating temperature. The development of infrared detectors depends on cheaper materials with high carrier mobility, tunable spectral response and compatibility with large-scale semiconductor processes. In recent years, the appearance of mercury telluride colloidal quantum dots (HgTe CQDs) provided a new choice for infrared detection and had attracted wide attention due to their excellent optical properties, solubility processability, mechanical flexibility and size-tunable absorption features. In this review, we summarized the recent progress of HgTe CQDs based infrared detectors, including synthesis, device physics, photodetection mechanism, multi-spectral imaging and focal plane array (FPA).
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Sun, Xiaoli, Daniel R. Cremons, Erwan Mazarico, Guangning Yang, James B. Abshire, David E. Smith, Maria T. Zuber et al. "Small All-Range Lidar for Asteroid and Comet Core Missions". Sensors 21, n.º 9 (28 de abril de 2021): 3081. http://dx.doi.org/10.3390/s21093081.
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We report the development of a new type of space lidar specifically designed for missions to small planetary bodies for both topographic mapping and support of sample collection or landing. The instrument is designed to have a wide dynamic range with several operation modes for different mission phases. The laser transmitter consists of a fiber laser that is intensity modulated with a return-to-zero pseudo-noise (RZPN) code. The receiver detects the coded pulse-train by correlating the detected signal with the RZPN kernel. Unlike regular pseudo noise (PN) lidars, the RZPN kernel is set to zero outside laser firing windows, which removes most of the background noise over the receiver integration time. This technique enables the use of low peak-power but high pulse-rate lasers, such as fiber lasers, for long-distance ranging without aliasing. The laser power and the internal gain of the detector can both be adjusted to give a wide measurement dynamic range. The laser modulation code pattern can also be reconfigured in orbit to optimize measurements to different measurement environments. The receiver uses a multi-pixel linear mode photon-counting HgCdTe avalanche photodiode (APD) array with near quantum limited sensitivity at near to mid infrared wavelengths where many fiber lasers and diode lasers operate. The instrument is modular and versatile and can be built mostly with components developed by the optical communication industry.
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Bruce, D. M., R. J. Seymour, D. Cheong, P. E. Jessop y B. K. Garside. "Ultrafast interdigital photodetectors and integration with optical waveguides on silicon". Canadian Journal of Physics 65, n.º 8 (1 de agosto de 1987): 924–28. http://dx.doi.org/10.1139/p87-145.
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The development of new types of high-speed photodetectors and techniques to incorporate these detectors into integrated optical structures are reported in this paper. Schottky-barrier detectors with an interdigital electrode configuration have been fabricated on commercially available silicon-on-sapphire substrates. Response times of <30 ps have been measured for wavelengths from infrared to the ultraviolet. These experimental results agree well with a supporting numerical model of these detectors. Using the same electrode configuration, we have fabricated photoconductive detectors on bulk silicon and germanium-on-gallium arsenide substrates. These have slower response times, on the order of a nanosecond, but demonstrate a good responsivity of approximately 1.5 A∙W−1. Using a modified electrode configuration, we have fabricated an integrated detector array on silicon, combining a glass waveguide channel with each detector element for the efficient delivery of an optical input signal.
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Yasuoka, Yoshizumi y Kenji Suzuki. "Fabrication of slot antenna array coupled warm carrier far-infrared radiation detectors". Microelectronic Engineering 67-68 (junio de 2003): 528–33. http://dx.doi.org/10.1016/s0167-9317(03)00110-2.
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Schaeberle, Michael D. y Patrick J. Treado. "New frontiers in multispectral chemical imaging". Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 156–57. http://dx.doi.org/10.1017/s0424820100168517.
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Recent advancements in visible and near-infrared multichannel detectors as well as the availability of novel imaging quality tunable filters make multispectral chemical imaging microscopy viable for routine materials characterization. Our research involves the development and application of chemical imaging methods that are rapid, non-invasive, and intuitive. The methods require limited sample preparation, and can be performed at high spectral and spatial resolution.The chemical imaging techniques employ Raman scattering, fluorescence emission or infrared absorption spectroscopies in combination with optical microscopy. In general, the methods provide qualitative and quantitative information about the composition and distribution of constituents within a wide host of materials, including biological tissues, polymers, and semiconductors.Silicon charge-coupled device (CCD) detectors are widely utilized for image detection in visible microscopy. Currently underutilized, but providing significant capabilities for chemical imaging based on infrared vibrational absorption are focal plane array (FPA) detectors providing sensitivity in the near-infrared and mid infrared. These include cameras constructed from indium antimonide (InSb), platinum silicide (PtSi), indium gallium arsenide (InGaAs) and mercury cadmium telluride (MCT).
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Prabhakar, Shashi, Taylor Shields, Adetunmise C. Dada, Mehdi Ebrahim, Gregor G. Taylor, Dmitry Morozov, Kleanthis Erotokritou et al. "Two-photon quantum interference and entanglement at 2.1 μm". Science Advances 6, n.º 13 (marzo de 2020): eaay5195. http://dx.doi.org/10.1126/sciadv.aay5195.
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Quantum-enhanced optical systems operating within the 2- to 2.5-μm spectral region have the potential to revolutionize emerging applications in communications, sensing, and metrology. However, to date, sources of entangled photons have been realized mainly in the near-infrared 700- to 1550-nm spectral window. Here, using custom-designed lithium niobate crystals for spontaneous parametric down-conversion and tailored superconducting nanowire single-photon detectors, we demonstrate two-photon interference and polarization-entangled photon pairs at 2090 nm. These results open the 2- to 2.5-μm mid-infrared window for the development of optical quantum technologies such as quantum key distribution in next-generation mid-infrared fiber communication systems and future Earth-to-satellite communications.
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Erfanian, Alireza, Hamed Mehrara, Mahdi Khaje y Ahmad Afifi. "A room temperature 2 × 128 PtSi/Si-nanostructure photodetector array compatible with CMOS process". Sensor Review 35, n.º 3 (15 de junio de 2015): 282–86. http://dx.doi.org/10.1108/sr-11-2014-0736.
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Purpose – The purpose of this paper is to demonstrate a successful fabrication of 2 × 128 linear array of typical infrared (IR) detectors made of p-type tSi/porous Si Schottky barrier. Design/methodology/approach – Using metal-assisted chemical etching (MaCE) as a unique approach, a sample definition of a porous Si nanostructure region for fabricating of any high-density photodetectors array has been formulated. Besides, the uniformity of pixels at different position along the array has been confirmed by optical images and measurements of photocurrent in IR regime at room temperature. Findings – The experimental result illustrates the existence of an open-circuit voltage up to 30 mV at 1.5-μm wavelength for an area of 50 × 50 μm2. Additionally, this behavior is almost the same at different pixels of fabricated array. Research limitations/implications – The uniformity of pixels and definition of nanostructure region are two most important challenges in fabrication of any high-density photodetectors array. Practical implications – MaCE guarantees formation of reproducible, high-fidelity and controllable nanometer-size porous Si with well-defined and sharp edges of the patterned areas. Originality/value – The proposed method offers a low-cost and simple process to fabricate high-density arrays of Schottky detectors which are compatible with the complementary metal-oxide semiconductor process.
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Esfahani, Siavash, Akira Tiele, Samuel O. Agbroko y James A. Covington. "Development of a Tuneable NDIR Optical Electronic Nose". Sensors 20, n.º 23 (1 de diciembre de 2020): 6875. http://dx.doi.org/10.3390/s20236875.
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Electronic nose (E-nose) technology provides an easy and inexpensive way to analyse chemical samples. In recent years, there has been increasing demand for E-noses in applications such as food safety, environmental monitoring and medical diagnostics. Currently, the majority of E-noses utilise an array of metal oxide (MOX) or conducting polymer (CP) gas sensors. However, these sensing technologies can suffer from sensor drift, poor repeatability and temperature and humidity effects. Optical gas sensors have the potential to overcome these issues. This paper reports on the development of an optical non-dispersive infrared (NDIR) E-nose, which consists of an array of four tuneable detectors, able to scan a range of wavelengths (3.1–10.5 μm). The functionality of the device was demonstrated in a series of experiments, involving gas rig tests for individual chemicals (CO2 and CH4), at different concentrations, and discriminating between chemical standards and complex mixtures. The optical gas sensor responses were shown to be linear to polynomial for different concentrations of CO2 and CH4. Good discrimination was achieved between sample groups. Optical E-nose technology therefore demonstrates significant potential as a portable and low-cost solution for a number of E-nose applications.
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Santarelli, Maria Filomena, Giulio Giovannetti, Valentina Hartwig, Simona Celi, Vincenzo Positano y Luigi Landini. "The Core of Medical Imaging: State of the Art and Perspectives on the Detectors". Electronics 10, n.º 14 (10 de julio de 2021): 1642. http://dx.doi.org/10.3390/electronics10141642.
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In this review, the roles of detectors in various medical imaging techniques were described. Ultrasound, optical (near-infrared spectroscopy and optical coherence tomography) and thermal imaging, magnetic resonance imaging, computed tomography, single-photon emission tomography, positron emission tomography were the imaging modalities considered. For each methodology, the state of the art of detectors mainly used in the systems was described, emphasizing new technologies applied.
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Anand, Vijayakumar, Soon Hock Ng, Tomas Katkus, Jovan Maksimovic, Annaleise R. Klein, Jitraporn Vongsvivut, Keith R. Bambery, Mark J. Tobin y Saulius Juodkazis. "Exploiting spatio-spectral aberrations for rapid synchrotron infrared imaging". Journal of Synchrotron Radiation 28, n.º 5 (9 de agosto de 2021): 1616–19. http://dx.doi.org/10.1107/s1600577521007104.
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The Infrared Microspectroscopy Beamline at the Australian Synchrotron is equipped with a Fourier transform infrared (FTIR) spectrometer, which is coupled with an infrared (IR) microscope and a choice of two detectors: a single-point narrow-band mercury cadmium telluride (MCT) detector and a 64 × 64 multi-pixel focal plane array (FPA) imaging detector. A scanning-based point-by-point mapping method is commonly used with a tightly focused synchrotron IR beam at the sample plane, using an MCT detector and a matching 36× IR reflecting objective and condenser (NA = 0.5), which is time consuming. In this study, the beam size at the sample plane was increased using a 15× objective and the spatio-spectral aberrations were investigated. A correlation-based semi-synthetic computational optical approach was applied to assess the possibilities of exploiting the aberrations to perform rapid imaging rather than a mapping approach.
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Ojonah, Emeakpo. "Downhole Fluid Analysis During Wellbore Sampling at High Temperatures Using a Pyroelectric Array Spectrometer". Journal of Petroleum Technology 73, n.º 05 (1 de mayo de 2021): 41–43. http://dx.doi.org/10.2118/0521-0041-jpt.
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While the world is transitioning into a greener and less-carbon-rich energy source, the fact remains that there is a growing need for exploration and production of hydrocarbons in previously untapped resources. These frontier reservoirs, while extremely hot, are prolific and make the footprint of the exploration activity much smaller than shallower drilling, which would require many more wells to deliver the same amount of hydrocarbon. These frontier wells, classified as high-pressure/high-temperature (HP/HT) wells, are defined as wells with reservoir or bottomhole temperatures higher than 300°F and which require pressure-control equipment with a rating above 10,000 psi. HP/HT wells can be found offshore in the North Sea and Gulf of Mexico, or on land—as seen recently in the Gongola Basin. Fluid identification, which is a critical process in fluid sampling, continues to be a challenge in temperatures above 350°F. At temperatures up to 450°F, fluid identification is currently achieved by bubblepoint and compressibility measurements, which cannot quantitatively measure contamination levels of the subject sample fluid. A possible solution to this problem would involve using pyroelectric detectors in the process of estimating a property of a downhole fluid. The method and apparatus in this approach involves exposing a fluid to modulated light downhole and sensing changes in the intensity of infrared radiation from the downhole fluid, to estimate the level of filtrate contamination and other properties. The pyroelectric detector senses changes in the intensity of light by con-verting the transient changes in temperature of its detector and performs the spectroscopic fluid analysis by optically filtering the light allowed to impinge on it, converting the changes in temperature of the pyroelectric detector to a signal which can then be used to estimate the property of the downhole fluid. If successfully implemented, this would enable the wireline-logging industry to develop an optical fluid analyser capable of quantitatively measuring fluid contamination levels in high-temperature (greater than 300°F) environments. Theory Pyroelectric infrared detectors (PIR) convert the changes in incoming infrared light to electric signals. Pyroelectric materials are characterized by having spontaneous electric polarization, which is altered by temperature changes as infrared light illuminates the elements. Pyroelectric detectors (Fig. 1) are thermal detectors, meaning they produce a signal in response to a change in their temperature. Below a case temperature (Tc) known as the Curie point, ferroelectric materials such as lithium tantalate exhibit a large spontaneous electrical polarization. If the temperature of such a material is altered, for example by incident radiation, the polarization changes. This change in polarization may be observed as an electrical signal when electrodes are placed on opposite faces of a thin slice of the material to form a capacitor. When the polarization changes, if the external impedance is comparatively high, the charges induced in the electrodes can be made to produce a voltage across the slice. The sensor will only produce an electrical output signal when the temperature changes; that is, when the level of incident-radiation changes.
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Bondar, A., A. Buzulutskov, A. Dolgov, E. Shemyakina y A. Sokolov. "Study of combined THGEM/GAPD-matrix multiplier in a two-phase Cryogenic Avalanche Detector in Ar". EPJ Web of Conferences 174 (2018): 02005. http://dx.doi.org/10.1051/epjconf/201817402005.
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Two-phase Cryogenic Avalanche Detectors (CRADs) with combined THGEM/GAPD-matrix multiplier have become an emerging technique in rare-event experiments such as those of coherent neutrino-nucleus scattering and dark matter search. In this work we continue to study the performance of the two-phase CRAD in Ar with THGEM/GAPD-matrix charge/optical readout. The matrix was composed of a 3×3 array of GAPDs (Geiger-mode APDs), optically recording THGEM-hole avalanches in the Near Infrared (NIR). Gain, time, amplitude and spatial resolution properties of the combined multiplier are described.
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Hall, David, Yu-Hsin Liu y Yu-Hwa Lo. "Single photon avalanche detectors: prospects of new quenching and gain mechanisms". Nanophotonics 4, n.º 4 (6 de noviembre de 2015): 397–412. http://dx.doi.org/10.1515/nanoph-2015-0021.
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AbstractWhile silicon single-photon avalanche diodes (SPAD) have reached very high detection efficiency and timing resolution, their use in fibre-optic communications, optical free space communications, and infrared sensing and imaging remains limited. III-V compounds including InGaAs and InP are the prevalent materials for 1550 nm light detection. However, even the most sensitive 1550 nm photoreceivers in optical communication have a sensitivity limit of a few hundred photons. Today, the only viable approach to achieve single-photon sensitivity at 1550 nm wavelength from semiconductor devices is to operate the avalanche detectors in Geiger mode, essentially trading dynamic range and speed for sensitivity. As material properties limit the performance of Ge and III-V detectors, new conceptual insight with regard to novel quenching and gain mechanisms could potentially address the performance limitations of III-V SPADs. Novel designs that utilise internal self-quenching and negative feedback can be used to harness the sensitivity of single-photon detectors,while drastically reducing the device complexity and increasing the level of integration. Incorporation of multiple gain mechanisms, together with self-quenching and built-in negative feedback, into a single device also hold promise for a new type of detector with single-photon sensitivity and large dynamic range.
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Zhou, Nan, Miao Qing Zhuang y Hao Liang. "Design of High Speed and High Efficiency Single-Photon Detectors Using Silicon Avalanche Photodiodes". Key Engineering Materials 705 (agosto de 2016): 168–73. http://dx.doi.org/10.4028/www.scientific.net/kem.705.168.
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Avalanche photodiodes are crucial materials for single-photon detection. Single-photon detectors are indispensable components for optical experiments and applications such as quantum information processing and quantum communications, both of which demand high single-photon detection efficiency. The authors have first developed a silicon single-photon avalanche detector in near infrared spectrum with 1 MHz square wave gating and tested its performance. Then we have also designed a high-speed and high-efficiency silicon single-photon detection system with 152 MHz sine wave gating and improved its single-photon detection efficiency to 77.48%.
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Christou, J. C. "Speckle Interferometry". Highlights of Astronomy 8 (1989): 561–62. http://dx.doi.org/10.1017/s1539299600008340.
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Speckle interferometry is a technique which utilizes the full diffraction-limited imaging potential of ground-based telescopes. Short exposure images, or specklegrams, with an exposure time less than that of the atmospheric correlation time (~5- 50 ms) preserve the high-spatial frequency information lost in long exposure imaging. In 1970, Labeyrie computed the power spectrum of a set of specklegrams and showed that they contained diffraction-limited information. Since then the field has grown with improvements in both instrumentation and the phase recovery algorithms necessary for imaging. It has been applied at both visible and near-infrared wavelengths although, until recently, the latter has used slit-scanning techniques with single pixel detectors because of the lack of array detectors. The current state of speckle interferometry has been well covered in the proceedings of two recent joint National Optical Astronomy Observatories – European Southern Observatory workshops on Interferometric Imaging in Astronomy (Oracle, 1987 & Garching, 1988).
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Zhao, Jicong, Mingmin Ge, Chenguang Song, Ling Sun y Haiyan Sun. "A Novel 3D Encapsulation Structure Based on Subwavelength Structure and Inserted Pyrex Glass for RF MEMS Infrared Detectors". Electronics 8, n.º 9 (31 de agosto de 2019): 974. http://dx.doi.org/10.3390/electronics8090974.
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A novel wafer-level three-dimensional (3D) encapsulation structure was designed for radio-frequency microelectromechanical system (RF MEMS) infrared detectors and investigated by using the finite element method (FEM) simulation. A subwavelength structure with a circular array of coaxial apertures was designed to obtain an extraordinary optical transmission (EOT) on top of a silicon substrate. For perpendicular incident light, a maximum transmission of 56% can be achieved in the long-wave infrared (LWIR) region and the transmission bandwidth covered almost the full LWIR region. Moreover, the maximum transmission could be further promoted with an increase in the incident angle. The vertical silicon vias, insulated by inserted Pyrex glass, were used to generate electrical contacts. With the optimized structure parameters, a feed-through level lower than −82 dB, and a transmission coefficient of one single via of more than −0.032 dB were obtained at a frequency from 0 to 2 GHz, which contributed to the low-loss transmission of the RF signals. Due to the matched thermal expansion coefficients (TECs) between silicon and Pyrex glass, the proposed via structure has excellent thermal reliability. Moreover, its thermal stress is much less than that of a conventional through-silicon via (TSV) structure. These calculated results demonstrate that the proposed 3D encapsulation structure shows enormous potential in RF MEMS infrared detector applications.
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Sethi, Waleed Tariq, Olivier De Sagazan, Mohamed Himdi, Hamsakutty Vettikalladi y Saleh A. Alshebeili. "Thermoelectric Sensor Coupled Yagi–Uda Nanoantenna for Infrared Detection". Electronics 10, n.º 5 (24 de febrero de 2021): 527. http://dx.doi.org/10.3390/electronics10050527.
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We present an experimental demonstration of a thermoelectric sensor coupled with a nanoantenna as an alternative option for detecting infrared energy. Two nanoantenna design (single element and an array) variations based on Yagi-Uda technology and one separate nano-thermoelectric junction array were fabricated and tested. The nanoantennas were tuned to operate and respond at a center wavelength of 1550 nm (193.5 THz) optical C-band window, but they also exhibited a resonance response when excited by lasers of various wavelengths (650 nm and 940 nm). The radiation-induced electric currents in the nanoantennas, coupled with a nano-thermoelectric sensor, produced a potential difference as per the Seebeck effect. With respect to the uniform thermal measurements of the reference nanoantenna, the experiments confirmed the detection properties of the proposed nanoantennas; the single element detected a peak percentage voltage hike of 28%, whereas the array detected a peak percentage voltage hike of 80% at the center wavelength. Compared to state-of-the-art thermoelectric designs, this was the first time that such peak percentage voltages were experimentally reported following a planar design based on the Seebeck principle.
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Richichi, A. "Lunar Occultations: From Past to Future Achievements". Symposium - International Astronomical Union 158 (1994): 71–81. http://dx.doi.org/10.1017/s0074180900107338.
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For several decades, lunar occultations have represented a powerful and productive technique for high angular resolution investigations of a broad class of astronomical sources: from stellar angular diameters to close binaries, from circumstellar shells to the Galactic Centre.The resolution and sensitivity offered by lunar occultations still compare favorably with the capabilities of other more modern methods in the optical and near-infrared. A remarkable fact, when one considers that during the past 20 years practically nothing or very little has changed in the way we observe lunar occultations: a sharp contrast with the impressive technological and scientific advancements of other techniques.The novel possibility of using small areas of fast-readout, low-noise array detectors to record lunar occultations, however, is about to bring radical improvements. We discuss the impact of such detectors on the efficiency of observation and the gain for what concerns the resolution and sensitivity of lunar occultations measurements. New applications such as wavelength-resolved observations and investigations of low-contrast extended sources appear particularly interesting.
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Hassan, MD Zoheb, Tanveer Ahmed Bhuiyan, S. M. Shahrear Tanzil y S. P. Majumder. "Turbo-Coded MC-CDMA Communication Link over Strong Turbulence Fading Limited FSO Channel with Receiver Space Diversity". ISRN Communications and Networking 2011 (22 de agosto de 2011): 1–14. http://dx.doi.org/10.5402/2011/701670.
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This paper demonstrates an analytical approach on the bit error rate (BER) performance evaluation of a multi- carrier code division multiple access (MC-CDMA) communication link operating over terrestrial free space optical (FSO) channel considering effect of atmospheric turbulence The turbulence induced intensity fading is statistically modeled by Gamma-Gamma PDF (probability density function). Bit error rate performance improvement is proposed using photo detector spatial diversity with Equal Gain Combining (EGC) and Turbo Coding. Analysis is carried out with different bandwidth efficient phase shift keying (PSK) based sub-carrier intensity modulation (SIM) with direct detection. Numerical simulation results of proposed analytical model indicate that, sub-carrier intensity modulation scheme; number of receiver photo detectors, turbo coding parameter and link length should be optimally engineered for ensuring system reliability. It can be inferred from the simulation that, a reliable communication link ( BER) can be established over a link length of 4 Km in strong turbulence fading condition using an array of 4 PIN photo detectors, 8-ary PSK based sub-carrier intensity modulation scheme and appropriate turbo coding parameter with an average 10.2 dB CINR (Carrier to Interference and Noise Ratio) requirement per photo detector. Besides, more than 130 dB average CINR gain is also confirmed from BPSK modulated, un-coded SISO (single input-single output) system for maintaining targeted BER () in presence of strong turbulence fading.
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Llewellyn, E. J., N. D. Lloyd, D. A. Degenstein, R. L. Gattinger, S. V. Petelina, A. E. Bourassa, J. T. Wiensz et al. "The OSIRIS instrument on the Odin spacecraft". Canadian Journal of Physics 82, n.º 6 (1 de junio de 2004): 411–22. http://dx.doi.org/10.1139/p04-005.
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The optical spectrograph and infrared imager system (OSIRIS) on board the Odin spacecraft is designed to retrieve altitude profiles of terrestrial atmospheric minor species by observing limb-radiance profiles. The grating optical spectrograph (OS) obtains spectra of scattered sunlight over the range 280800 nm with a spectral resolution of approximately 1 nm. The Odin spacecraft performs a repetitive vertical limb scan to sweep the OS 1 km vertical field of view over selected altitude ranges from approximately 10 to 100 km. The terrestrial absorption features that are superimposed on the scattered solar spectrum are monitored to derive the minor species altitude profiles. The spectrograph also detects the airglow, which can be used to study the mesosphere and lower thermosphere. The other part of OSIRIS is a three-channel infrared imager (IRI) that uses linear array detectors to image the vertical limb radiance over an altitude range of approximately 100 km. The IRI observes both scattered sunlight and the airglow emissions from the oxygen infrared atmospheric band at 1.27 µm and the OH (3-1) Meinel band at 1.53 µm. A tomographic inversion technique is used with a series of these vertical images to derive the two-dimensional distribution of the emissions within the orbit plane. PACS Nos.: 07.05.Pj, 07.60.Dq, 07.60.Rd, 07.87, 94.10.Dy, 94.10.Fa, 94.10.Gb, 94.10.Rk
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Krishnan, A., M. E. Bisher y M. M. J. Treacy. "In Situ Observation of Ferroelectric Domain Motion in BaTiO3". Microscopy and Microanalysis 5, S2 (agosto de 1999): 780–81. http://dx.doi.org/10.1017/s1431927600017220.
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Ferroelectrics are used in many applications such as non-volatile memory, infrared detectors, phased array radar and optical switches. While substantial progress has been made in the development of commercial ferroelectric devices, we still do not possess a good understanding of the fundamental processes in ferroelectrics. Trapped charge and oxygen vacancies are believed to strongly influence domain motion. In order to study these issues, we have designed an in situ TEM holder that can subject ferroelectric crystals to voltage, heat and UV irradiation.Bulk BaTi03 crystals, grown by the Remeika method, were mechanically polished and thinned in hot ophosphoric acid. The resulting thin flakes were attached to copper rings with conductive carbon paint and electrical wires were glued to the copper rings, which act as electrodes. The sample was placed in the cradle of the in situ TEM holder and examined in a Hitachi H9000NAR TEM.
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McLean, Ian S., Ding-Qiang Su, Thomas Armstrong, Noah Brosch, Martin Cullum, Michel Dennefeld, George Jacoby et al. "Commission 9: Instrumentation and Techniques: (Instrumentation et Techniques)". Transactions of the International Astronomical Union 24, n.º 1 (2000): 316–27. http://dx.doi.org/10.1017/s0251107x00003266.
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The last triennium, and coincidentally the last few years of the 20th century, has been a most remarkable time for Commission 9, and for astronomy in general. Ground-based astronomy in particular has received an enormous boost due to the arrival of an astonishing array of new telescopes, novel instruments and innovative techniques. For those of us closely involved in developing new observatories, instrumentation or detectors, the last few years have been rather hectic! As an astronomer with a long-time interest in the development of new instruments, what amazes me is the breadth of technology and the visionary scope of all these incredible new achievements. Many of the very large 8-10 meter class telescopes are now coming into full operation – yet, just as this is happening, numerous smaller “survey” telescopes are providing a wealth of new sources. Adaptive optics is being practiced at many sites and diffraction-limited imaging from the ground is now a reality. Several optical-IR interferometers are now working and more are coming along very soon. Detectors continue to get bigger and better, especially for the infrared, and instrumentation is increasingly more sophisticated, complex and efficient. Remote observing, robotic telescopes and global networks of telescopes are common, and international collaborations are larger and stronger than ever before.
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Krishnan, A., M. M. J. Treacy, M. E. Bisher, P. Chandra y P. B. Littlewood. "Maxwellian Charge on Ferroelectric Domain Walls in KNBO3". Microscopy and Microanalysis 6, S2 (agosto de 2000): 398–99. http://dx.doi.org/10.1017/s1431927600034486.
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Ferroelectrics are now being used as non-volatile memories, infrared detectors, phased array radar and optical switches. Although the development of commercial ferroelectric devices has advanced in recent years, we still do not have a clear understanding of the basic physics underpinning the behavior of actual ferroelectric devices. Trapped charge and oxygen vacancies are believed to strongly influence domain motion. In order to study these issues, we have designed an in situ TEM holder that can subject ferroelectric crystals to voltage, heat and UV irradiation. Preliminary results on BaTiO3 have been presented in previous reports.In this study, bulk KNbO3 crystals were mechanically polished and thinned in hot orthophosphoric acid. The resulting thin flakes were attached to copper rings with conductive carbon paint, and electrical wires were glued to the copper rings which act as electrodes. The sample was placed in the cradle of the in situ TEM holder and examined in a Hitachi H9000NAR TEM.
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Pascale, Michelangelo. "Detection methods for mycotoxins in cereal grains and cereal products". Zbornik Matice srpske za prirodne nauke, n.º 117 (2009): 15–25. http://dx.doi.org/10.2298/zmspn0917015p.
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Analytical methods for mycotoxins in cereals and cereal-based products require three major steps, including extraction, clean-up (to eliminate interferences from the extract and concentrate the analyte), and detection/determination of the toxin (by using suitable analytical instruments/technologies). Clean-up is essential for the analysis of mycotoxins at trace levels, and involves the use of solid phase extraction and multifunctional (e.g. MycoSep?) or immunoaffinity columns. Different chromatographic methods are commonly used for quantitative determination of mycotoxins, including gas-chromatography (GC) coupled with electron capture, flame ionization or mass spectrometry (MS) detectors (mainly for type-A trichothecenes), and high-performance liquid chromatography (HPLC) coupled with ultraviolet, diode array, fluorescence or MS detectors. The choice of method depends on the matrix and the mycotoxin to be analyzed. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is spreading rapidly as a promising technique for simultaneous screening, identification and quantitative determination of a large number of mycotoxins. In addition, commercial immunometric assays, such as enzyme-linked immunosorbent assays (ELISA), are frequently used for screening purposes as well. Recently, a variety of emerging methods have been proposed for the analysis of mycotoxins in cereals based on novel technologies, including immunochromatography (i.e. lateral flow devices), fluorescence polarization immunoassays (FPIA), infrared spectroscopy (FT-NIR), molecularly imprinted polymers (MIPs) and optical biosensors.
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Aalizadeh, Majid, Andriy E. Serebryannikov, Ekmel Ozbay y Guy A. E. Vandenbosch. "A simple Mie-resonator based meta-array with diverse deflection scenarios enabling multifunctional operation at near-infrared". Nanophotonics 9, n.º 15 (29 de septiembre de 2020): 4589–600. http://dx.doi.org/10.1515/nanoph-2020-0386.
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AbstractDeflection, a basic functionality of wavefront manipulation is usually associated with the phase-gradient metasurfaces and the classical blazed gratings. We numerically and experimentally demonstrate an unusually wideband and simultaneously wide-angle deflection achieved at near-infrared in reflection mode for a periodic (nongradient), ultrathin meta-array comprising only one silicon nanorod (Mie resonator) per period. It occurs in the range where only the first negative diffraction order and zero order may propagate. Deflection serves as the enabler for multifunctional operation. Being designed with the main goal to obtain ultra-wideband and wide-angle deflection, the proposed meta-array is also capable in spatial filtering and wide-angle splitting. Spatial filtering of various types can be obtained in one structure by exploiting either deflection in nonzero diffraction orders, or the specular-reflection (zero-order) regime. Thus, the role of different diffraction orders is clarified. Moreover, on–off switching of deflection and related functionalities is possible by changing polarization state of the incident wave. The suggested device is simple to fabricate and only requires cost-effective materials, so it is particularly appropriate for the large-area fabrication using nanoprint lithography. Ultra-wideband wide-angle and other deflection scenarios, along with the other functionalities, are promising for applications in optical communications, laser optics, sensing, detection, and imaging.
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Mely, L. Ansel, P. Annie Vinosha, M. Mary Jaculine, D. J. Vidhya Raj, K. Raja, J. Ermine Jose y S. Jerome Das. "Investigations on Hydrothermally Prepared Tin Mono-Sulphide Nanoparticles". Nano Hybrids and Composites 17 (agosto de 2017): 79–87. http://dx.doi.org/10.4028/www.scientific.net/nhc.17.79.
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Optically active, tin mono-sulphide (SnS) nanoparticles, having generic name herzenbergite, being one of the narrow band gap IV–VI semiconductors, geared up recently the attention of material scientists for its applications in photovoltaics, near-infrared detectors, and biomedical applications where strong scientific information on infrared absorption is required. Among the class of chalcopyrite semiconductors, SnS is a relatively inexpensive and non-toxic material with the nature of resource abundance for solar cell applications, having a bulk direct band gap of 1.3 eV and indirect bandgap of 1.1 eV, possessing high figure of merit such as optimum optical band gap, high optical absorption coefficient for photons and high photoelectric conversion efficiency of up to 25%. In the present work, nanostructured SnS particles of 11.75 nm were synthesized by means of a cinch hydrothermal reaction using the reagents tin chloride pentahydrate and thiourea at 200°C. The crystallinity, purity, morphology, and structural featuresof as-prepared nanoparticles were characterized by Powder X-ray Diffraction (XRD), Transmission Electron Microscope (TEM), UV-visible spectroscopy (Uv-vis), Photoluminescence spectroscopy (PL) and Fourier Transform Infra-red Spectroscopy (FTIR). XRD measurements reveal the formation of well-crystallized orthorhombic tin mono-sulphide nanoparticles which may be considered as a distorted NaCl structure. TEM observations demonstrate the morphology of the nanoparticles. The FTIR examination confirmed the existence of the vital functional groups. Absorption spectrum showed that the nanoparticles have an extensive absorption array. The optical properties determined by Uv-vis and PL measurements show that the prepared SnS nanoparticles will be an ideal candidate for photovoltaic applications.
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Soo Lee, Dong, Seong-sik Min y Man Seop Lee. "Design and analysis of spatially variant microlens-array diffuser with uniform illumination for short-range infrared wireless communications using photometric approach". Optics Communications 219, n.º 1-6 (abril de 2003): 49–55. http://dx.doi.org/10.1016/s0030-4018(03)01314-2.
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Jacobson, Abram R., William Boeck y Christopher Jeffery. "Comparison of Narrow Bipolar Events with Ordinary Lightning as Proxies for the Microwave-Radiometry Ice-Scattering Signature". Monthly Weather Review 135, n.º 4 (1 de abril de 2007): 1354–63. http://dx.doi.org/10.1175/mwr3342.1.
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Abstract The narrow bipolar event (NBE) is a unique lightning discharge that has a short (∼10 μs) overall duration, lacks a prior leader phase, and produces too little light output to be visible by optical lightning detectors on satellites. NBEs thus have basic differences from ordinary lightning discharges, which occur in flashes lasting up to a fraction of a second, carry significant current in a “stroke” only after a leader stage that prepares the conductive channel, and produce copious light that is recordable from space. Thus, the authors are motivated to determine whether the meteorological setting of NBEs differs from, or is similar to, that of ordinary lightning. A previous paper started this project of comparing NBEs with ordinary lightning by comparing the placement of either type of lightning within spatial structures of cloud depth, as revealed by infrared cloud-top temperature. That previous study employed lightning data from the Los Alamos Sferic Array (LASA) in Florida. The present paper extends this approach to comparing LASA NBEs with ordinary lightning events’ spatial relationships to radiometric cloud imagery from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) 85-GHz channels. This form of radiometric imagery reveals the location of deep, active convective cores with more acute spatial selectivity than does the infrared cloud-top temperature. It was found that the behaviors of NBEs and ordinary lighting are, once again, indistinguishable, but with regard this time to proximity to deep convective cores as revealed by TMI.
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Nioka, S. y B. Chance. "NIR Spectroscopic Detection of Breast Cancer". Technology in Cancer Research & Treatment 4, n.º 5 (octubre de 2005): 497–512. http://dx.doi.org/10.1177/153303460500400504.
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Near infrared spectroscopy (NIRS) utilizes intrinsic optical absorption signals of blood, water, and lipid concentration available in the NIR window (600–1000 nm) as well as a developing array of extrinsic organic compounds to detect and localize cancer. This paper reviews optical cancer detection made possible through high tumor-tissue signal-to-noise ratio (SNR) and providing biochemical and physiological data in addition to those obtained via other methods. NIRS detects cancers in vivo through a combination of blood volume and oxygenation from measurements of oxy- and deoxy-hemoglobin giving signals of tumor angiogenesis and hypermetabolism. The Chance lab tends towards CW breast cancer systems using manually scannable detectors with calibrated low pressure tissue contact. These systems calculate angiogenesis and hypermetabolism by using a pair of wavelengths and referencing the mirror image position of the contralateral breast to achieve high ROC/AUC. Time domain and frequency domain spectroscopy were also used to study similar intrinsic breast tumor characteristics such as high blood volume. Other NIRS metrics are water-fat ratio and the optical scattering coefficient. An extrinsic FDA approved dye, ICG, has been used to measure blood pooling with extravasation, similar to Gadolinium in MRI. A key future development in NIRS will be new Molecular Beacons targeting cancers and fluorescing in the NIR window to enhance in vivo tumor-tissue ratios and to afford biochemical specificity with the potential for effective photodynamic anti-cancer therapies.
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Dohle, Rainer, Ilaria Sacco, Thomas Rittweg, Thomas Friedrich, Gerold Henning, Jörg Goßler y Peter Fischer. "LTCC-Based Highly Integrated SiPM Module with Integrated Liquid Cooling Channels for High Resolution Molecular Imaging". Journal of Microelectronics and Electronic Packaging 15, n.º 2 (1 de abril de 2018): 86–94. http://dx.doi.org/10.4071/imaps.562590.
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We present a very compact hybrid detection module based on an advanced liquid-cooled low temperature cofired ceramic (LTCC) substrate. The double sided hybrid combines 144 photo detectors and four specialized flip chip readout ASICs (Application specific Integrated Circuits) used for the readout of scintillation crystals with application in time-of-flight positron emission tomography (PET) combined with magnetic resonance imaging (MRI). If MRI images and PET images are combined, completely new medical diagnostic and treatment prospects are feasible because the two techniques are complementary and they will offer both anatomical and functional information. One of the biggest challenges is the development of miniaturized detector modules that are highly functional and MRI compatible. Our SiPM (Silicon Photomultiplier) module has an area of 32.8 by 32.0 mm2 and contains 12 × 12 SiPMs in a pitch of 2.5 mm2. The SiPM readout of the 144 channels is performed by four PETA6 ASICs. The LTCC substrate with a 2.1 mm thickness has been manufactured using the most advanced technologies developed at Micro Systems Engineering GmbH To guarantee the manufacturability in serial or mass production, DP951 P2 green tape has been used. For the cooling channels, special technology has been developed by MSE. The liquid cooling channels inside the LTCC substrate provide excellent cooling for the ASICs, the SiPMs, and thermal insulation between ASICs and SiPMs and allow a very compact design of the detector modules, reducing their height by 50% compared with other technical solutions. We can insert a ring of our modules in an existing MR (Magnetic Resonance) scanner. Operating the SiPMs at low temperature improves their performance, reducing the effects of dark count rate and improving image quality. There is no heatsink, heat pipe, or other cooling element attached to the back side of the ASICs. To avoid interference between the PET and MRI system, short signal length is required for minimizing pickup loops and eddy currents. The 12 SiPM arrays with 2 × 6 geometry are wire bonded only at the edges of the SiPMs to the LTCC, enabling the use of nearly the whole detector area for photon detection, which is of paramount importance for excellent image quality. At the opposite side of the substrate, four ASICs with 272 μm bump pitch are flip chip solder assembled to the LTCC substrate including underfilling, and a few SMD (Surface Mount Device) components are mounted. A scintillator crystal array on top of the SiPMs converts gamma rays (511 keV photons produced from positron-electron annihilation) into light. We assume that the LTCC substrates and all components are fully MRI compatible, which is important for the integration of PET with MRI without mutual interference. The paper elucidates the impact of the used technology on the performance of advanced PET/MRI detector modules.
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Algorri, Jose Francisco, Virginia Urruchi, Noureddine Bennis y Jose Manuel Sanchez-Pena. "Theoretical approach of a polymer stabilized blue phase beam steering". Photonics Letters of Poland 9, n.º 1 (31 de marzo de 2017): 14. http://dx.doi.org/10.4302/plp.v9i1.705.
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Nematic liquid crystal (LC)-based beam steering has been reported for wide applications. However, for conventional nematic LC beam steering the thickness is of several microns in order to have a wider deflection angle. The response time is relatively slow and the diffraction efficiency is low. In this work, novel beam steering based on polymer stabilized blue phase liquid crystal (PS-BPLC) has been designed and theoretically analyzed. This special mesophase of the chiral doped nematic LC has several advantageous characteristics, for example no need for alignment layers, microsecond response time and an isotropic voltage-off state. The results reveal control over phase retardation. The direction of the steered beam can be tuned by voltage. Depending on voltage configuration, either diffractive beam steering (0.5deg deviation for 1st order) or a tunable continuous phase (tunable deviation of 0.002deg) can be obtained. In the first case, the deflection angle could be tuned by stacks of samples. The second option has the same phase shift for the TE and TM modes so unpolarized light could be used. Full Text: PDF ReferencesF. Feng, I. White, T. Wilkinson, "Free Space Communications With Beam Steering a Two-Electrode Tapered Laser Diode Using Liquid-Crystal SLM", J. Lightwave Technol. 31, 2001 (2013). CrossRef E. Oton, J. Perez-Fernandez, D. Lopez-Molina, X. Quintana, J.M. Oton, M.A. Geday, "Reliability of Liquid Crystals in Space Photonics", IEEE Photonics Journal 7, 1 (2015). CrossRef J. Stockley, S. Serati, "Multi-access laser terminal using liquid crystal beam steering", IEEE in Aerospace Conference, 1972 (2005). CrossRef D. Zografopoulos and E. Kriezis, "Switchable beam steering with zenithal bistable liquid-crystal blazed gratings", Opt. Lett. 39, 5842 (2014). CrossRef Benedikt Scherger, et al., "Discrete Terahertz Beam Steering with an Electrically Controlled Liquid Crystal Device", J. Infrared. Millim. Terahertz Waves 33, 1117 (2012). CrossRef M.A. Geday, X. Quintana, E. Otón, B. Cerrolaza, D. Lopez, F. Garcia de Quiro, I. Manolis, A. Short, Proc. ICSO, Rhodes, Greece, pp. 1-4 (2010). CrossRef Y. Chen, S.-T. Wu, "The outlook for blue-phase LCDs", Proc. SPIE 9005, Advances in Display Technologies IV, 900508 (2014). CrossRef G.D. Love, A.F. Naumov, "Modal liquid crystal lenses", Liq. Cryst. Today 10, 1 (2000). CrossRef V. Urruchi, J.F. Algorri, J.M. Sánchez-Pena, M.A. Geday, X. Quintana, N. Bennis, "Lenticular Arrays Based on Liquid Crystals", Opto-Electron. Rev. 20, 38 (2012). CrossRef J.F. Algorri, G. Love, and V. Urruchi, "Modal liquid crystal array of optical elements", Opt. Express 21, 24809 (2013). CrossRef J.F. Algorri, V. Urruchi, N. Bennis, J. Sánchez-Pena, "Modal liquid crystal microaxicon array", Opt. Lett. 39, 3476 (2014). CrossRef J.F. Algorri, V. Urruchi, B. Garcia-Camara, J.M. Sánchez-Pena, "Generation of Optical Vortices by an Ideal Liquid Crystal Spiral Phase Plate", IEEE Elect. Dev. Lett. 35, 856 (2014). CrossRef D. Xu, Y. Chen, Y. Liu, S. Wu, "Refraction effect in an in-plane-switching blue phase liquid crystal cell", Opt. Express 21, 24721 (2013). CrossRef Z. Ge, S. Gauza, M. Jiao, H. Xianyu, S.T. Wu, "Electro-optics of polymer-stabilized blue phase liquid crystal displays", Appl. Phys. Lett. 94 101104 (2009). CrossRef J. Yan et al., "Extended Kerr effect of polymer-stabilized blue-phase liquid crystals", Appl. Phys. Lett. 96, 071105 (2010). CrossRef X. Wang, D. Wilson, R. Muller, P. Maker, D. Psaltis, "Liquid-crystal blazed-grating beam deflector, Appl. Opt. 39, 6545 (2000). CrossRef
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Strong, R., D. W. Greve y M. M. Weeks. "GeSi Infrared Detectors Using Selective Deposition". MRS Proceedings 402 (1995). http://dx.doi.org/10.1557/proc-402-443.
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AbstractHeterojunction p++ GeSi / Si internal photoemission (HIP) detectors deposited by ultra high vacuum chemical vapor deposition (UHV/CVD) were investigated as alternatives to silicide Schottky-barrier type detectors for infrared focal plane arrays. HIP structures were grown using SiH4, GeH4, and B2H6 source gases on (100) p- Si substrates patterned with thermal oxide windows. Selective epitaxy was maintained over a range of boron concentrations (6×1019 – 6.5×1020 cm-3) and Ge fractions (0.38–0.50), and a maximum selective thickness of ~300Å was determined for silicon growth at 550°C. These structures were fabricated into IR detectors using techniques compatible with standard Si focal plane array processing technology. Photoresponse data were analyzed according to the modified Fowler equation, indicating cut-off wavelengths of 5–12 (μm) and Cl values of 8–21 (%/eV) depending on sample parameters. I(V) characteristics were also measured at various temperatures, yielding electrical barrier heights consistent with optical measurements.
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Mashanovich, Goran, Wei Cao, Zhibo Qu, Ke Li, David Thomson, Milos Nedeljkovic, David Hagan y Andrew Knights. "Mid-Infrared Silicon Photonics for Communications". IJEEC - INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING AND COMPUTING 3, n.º 1 (29 de julio de 2019). http://dx.doi.org/10.7251/ijeec1901032m.
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The mid-infrared wavelength region is important for a number of application areas, two of which are optical fibre and free space communications. Silicon photonics can provide inexpensive photonic chips for such applications due to excellent electronic and photonic properties. In this paper, the realisation of active silicon and germanium photonic devices for the mid-infrared spectral region are given. High speed Si depletion type modulators, Si and Ge injection modulators operating at wavelengths up to 8 micrometers, and high speed Si detectors are presented. These devices are integrated with drivers and amplifiers and show very good performance, e.g. data rate in excess of 20 Gb/s.
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Torun, H. y H. Urey. "Uncooled thermo-mechanical detector array with optical readout". Opto-Electronics Review 14, n.º 1 (1 de enero de 2006). http://dx.doi.org/10.2478/s11772-006-0008-y.
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AbstractThis paper reports a novel uncooled infrared FPA whose performance is comparable to the cooled FPA’s in terms of noise parameters. FPA consists of bimaterial microcantilever structures that are designed to convert IR radiation energy into mechanical energy. Induced deflection by mechanical energy is detected by means of optical methods that measure sub nanometer thermally induced deflections. Analytical solutions are developed for calculating the figure of merits for the FPA. FEM simulations and the analytical solution agree well. Calculations show that for an FPA, NETD of < 5 mK is achievable in the 8–12 μm band. The design and optimization for the detectors are presented. The mechanical structure of pixels is designed such that it can be possible to form large array size FPA’s. Microfabrication of the devices to improve the performance further, employs low cost standard MEMS processes.
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Zhang, Shaoda, Wu Bin, Binbin Xu, Xingyu Zheng, Binbin Chen, Xueqin Lv, Haisheng San y Werner Hofmann. "Mixed-gas CH4/CO2/CO detection based on linear variable optical filter and thermopile detector array". Nanoscale Research Letters 14, n.º 1 (25 de noviembre de 2019). http://dx.doi.org/10.1186/s11671-019-3176-7.
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AbstractThis paper presents the design, fabrication, and characterization of a middle-infrared (MIR) linear variable optical filter (LVOF) and thermopile detectors that will be used in a miniaturized mixed gas detector for CH4/CO2/CO measurement. The LVOF was designed as a tapered-cavity Fabry-Pérot optical filter, which can transform the MIR continuous spectrum into multiple narrow band-pass spectra with peak wavelength in linear variation. Multi-layer dielectric structures were used to fabricate the Bragg reflectors on the both sides of tapered cavity as well as the antireflective film combined with the function of out-of-band rejection. The uncooled thermopile detectors were designed and fabricated as a multiple-thermocouple suspension structure using micro-electro-mechanical system technology. Experimentally, the LVOF exhibits a mean full-width-at-half-maximum of 400 nm and mean peak transmittance of 70% at the wavelength range of 2.3~5 μm. The thermopile detectors exhibit a responsivity of 146 μV/°C at the condition of room temperature. It is demonstrated that the detectors can achieve the quantification and identification of CH4/CO2/CO mixed gas.
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Vergara, G., M. Montojo, M. Torquemada, M. Rodrigo, F. Sánchez, L. Gómez, R. Almazán et al. "Polycrystalline lead selenide: the resurgence of an old infrared detector". Opto-Electronics Review 15, n.º 2 (1 de enero de 2007). http://dx.doi.org/10.2478/s11772-007-0007-7.
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AbstractThe existing technology for uncooled MWIR photon detectors based on polycrystalline lead salts is stigmatized for being a 50-year-old technology. It has been traditionally relegated to single-element detectors and relatively small linear arrays due to the limitations imposed by its standard manufacture process based on a chemical bath deposition technique (CBD) developed more than 40 years ago. Recently, an innovative method for processing detectors, based on a vapour phase deposition (VPD) technique, has allowed manufacturing the first 2D array of polycrystalline PbSe with good electro optical characteristics. The new method of processing PbSe is an all silicon technology and it is compatible with standard CMOS circuitry. In addition to its affordability, VPD PbSe constitutes a perfect candidate to fill the existing gap in the photonic and uncooled IR imaging detectors sensitive to the MWIR photons. The perspectives opened are numerous and very important, converting the old PbSe detector in a serious alternative to others uncooled technologies in the low cost IR detection market. The number of potential applications is huge, some of them with high commercial impact such as personal IR imagers, enhanced vision systems for automotive applications and other not less important in the security/defence domain such as sensors for active protection systems (APS) or low cost seekers.Despite the fact, unanimously accepted, that uncooled will dominate the majority of the future IR detection applications, today, thermal detectors are the unique plausible alternative. There is plenty of room for photonic uncooled and complementary alternatives are needed. This work allocates polycrystalline PbSe in the current panorama of the uncooled IR detectors, underlining its potentiality in two areas of interest, i.e., very low cost imaging IR detectors and MWIR fast uncooled detectors for security and defence applications. The new method of processing again converts PbSe into an emerging technology.
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Polovinkin, Vladimir G., Victor A. Stuchinsky, Aleksey V. Vishnyakov y Irlam I. Lee. "Monte Carlo Simulation of Photoelectric Characteristics of Mercury-Cadmium-Tellurium- Based Infrared Focal-Plane-Array Detectors". IEEE Transactions on Electron Devices, 2018, 1–7. http://dx.doi.org/10.1109/ted.2018.2872129.
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Tong, Jinchao, Fei Suo, Tianning Zhang, Zhiming Huang, Junhao Chu y Dao Hua Zhang. "Plasmonic semiconductor nanogroove array enhanced broad spectral band millimetre and terahertz wave detection". Light: Science & Applications 10, n.º 1 (15 de marzo de 2021). http://dx.doi.org/10.1038/s41377-021-00505-w.
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AbstractHigh-performance uncooled millimetre and terahertz wave detectors are required as a building block for a wide range of applications. The state-of-the-art technologies, however, are plagued by low sensitivity, narrow spectral bandwidth, and complicated architecture. Here, we report semiconductor surface plasmon enhanced high-performance broadband millimetre and terahertz wave detectors which are based on nanogroove InSb array epitaxially grown on GaAs substrate for room temperature operation. By making a nanogroove array in the grown InSb layer, strong millimetre and terahertz wave surface plasmon polaritons can be generated at the InSb–air interfaces, which results in significant improvement in detecting performance. A noise equivalent power (NEP) of 2.2 × 10−14 W Hz−1/2 or a detectivity (D*) of 2.7 × 1012 cm Hz1/2 W−1 at 1.75 mm (0.171 THz) is achieved at room temperature. By lowering the temperature to the thermoelectric cooling available 200 K, the corresponding NEP and D* of the nanogroove device can be improved to 3.8 × 10−15 W Hz−1/2 and 1.6 × 1013 cm Hz1/2 W−1, respectively. In addition, such a single device can perform broad spectral band detection from 0.9 mm (0.330 THz) to 9.4 mm (0.032 THz). Fast responses of 3.5 µs and 780 ns are achieved at room temperature and 200 K, respectively. Such high-performance millimetre and terahertz wave photodetectors are useful for wide applications such as high capacity communications, walk-through security, biological diagnosis, spectroscopy, and remote sensing. In addition, the integration of plasmonic semiconductor nanostructures paves a way for realizing high performance and multifunctional long-wavelength optoelectrical devices.