Science.gov

Sample records for pixel opto links

  1. Opto-box: Optical modules and mini-crate for ATLAS pixel and IBL detectors

    NASA Astrophysics Data System (ADS)

    Bertsche, David

    2016-11-01

    The opto-box is a custom mini-crate for housing optical modules which process and transfer optoelectronic data. Many novel solutions were developed for the custom design and manufacturing. The system tightly integrates electrical, mechanical, and thermal functionality into a small package of size 35×10x8 cm3. Special attention was given to ensure proper shielding, grounding, cooling, high reliability, and environmental tolerance. The custom modules, which incorporate Application Specific Integrated Circuits, were developed through a cycle of rigorous testing and redesign. In total, fourteen opto-boxes have been installed and loaded with modules on the ATLAS detector. They are currently in operation as part of the LHC run 2 data read-out chain. This conference proceeding is in support of the poster presented at the International Conference on New Frontiers in Physics (ICNFP) 2015 [1].

  2. Holographic opto-fluidic microscopy.

    PubMed

    Bishara, Waheb; Zhu, Hongying; Ozcan, Aydogan

    2010-12-20

    Over the last decade microfluidics has created a versatile platform that has significantly advanced the ways in which micro-scale organisms and objects are controlled, processed and investigated, by improving the cost, compactness and throughput aspects of analysis. Microfluidics has also expanded into optics to create reconfigurable and flexible optical devices such as reconfigurable lenses, lasers, waveguides, switches, and on-chip microscopes. Here we present a new opto-fluidic microscopy modality, i.e., Holographic Opto-fluidic Microscopy (HOM), based on lensless holographic imaging. This imaging modality complements the miniaturization provided by microfluidics and would allow the integration of microscopy into existing on-chip microfluidic devices with various functionalities. Our imaging modality utilizes partially coherent in-line holography and pixel super-resolution to create high-resolution amplitude and phase images of the objects flowing within micro-fluidic channels, which we demonstrate by imaging C. elegans, Giardia lamblia, and Mulberry pollen. HOM does not involve complicated fabrication processes or precise alignment, nor does it require a highly uniform flow of objects within microfluidic channels.

  3. OPTO-22 DRIVER. OPTO-22 Driver for LabView

    SciTech Connect

    Johnson, G.W.

    1991-01-28

    OPTO-22 DRIVER consists of a set of LabVIEW (National Instruments, Austin, TX) virtual instruments (VIs) that handle low-level communications with signal conditioning equipment by Opto-22 (Huntington Beach, CA). The OPTOMUX protocol is support, which requires the use of a serial port and supports multidrop communications. With this package, users can connect hundreds of Opto-22 modules to their LabVIEW system and access all features of the hardware, including analog and digital input and outputs.

  4. Linking DICOM pixel data with radiology reports using automatic semantic annotation

    NASA Astrophysics Data System (ADS)

    Pathak, Sayan D.; Kim, Woojin; Munasinghe, Indeera; Criminisi, Antonio; White, Steve; Siddiqui, Khan

    2012-02-01

    Improved access to DICOM studies to both physicians and patients is changing the ways medical imaging studies are visualized and interpreted beyond the confines of radiologists' PACS workstations. While radiologists are trained for viewing and image interpretation, a non-radiologist physician relies on the radiologists' reports. Consequently, patients historically have been typically informed about their imaging findings via oral communication with their physicians, even though clinical studies have shown that patients respond to physician's advice significantly better when the individual patients are shown their own actual data. Our previous work on automated semantic annotation of DICOM Computed Tomography (CT) images allows us to further link radiology report with the corresponding images, enabling us to bridge the gap between image data with the human interpreted textual description of the corresponding imaging studies. The mapping of radiology text is facilitated by natural language processing (NLP) based search application. When combined with our automated semantic annotation of images, it enables navigation in large DICOM studies by clicking hyperlinked text in the radiology reports. An added advantage of using semantic annotation is the ability to render the organs to their default window level setting thus eliminating another barrier to image sharing and distribution. We believe such approaches would potentially enable the consumer to have access to their imaging data and navigate them in an informed manner.

  5. Coupled opto-electronic oscillator

    NASA Technical Reports Server (NTRS)

    Yao, X. Steve (Inventor); Maleki, Lute (Inventor)

    1999-01-01

    A coupled opto-electronic oscillator that directly couples a laser oscillation with an electronic oscillation to simultaneously achieve a stable RF oscillation at a high frequency and ultra-short optical pulsation by mode locking with a high repetition rate and stability. Single-mode selection can be achieved even with a very long opto-electronic loop. A multimode laser can be used to pump the electronic oscillation, resulting in a high operation efficiency. The optical and the RF oscillations are correlated to each other.

  6. Opto-electronic morphological processor

    NASA Technical Reports Server (NTRS)

    Yu, Jeffrey W. (Inventor); Chao, Tien-Hsin (Inventor); Cheng, Li J. (Inventor); Psaltis, Demetri (Inventor)

    1993-01-01

    The opto-electronic morphological processor of the present invention is capable of receiving optical inputs and emitting optical outputs. The use of optics allows implementation of parallel input/output, thereby overcoming a major bottleneck in prior art image processing systems. The processor consists of three components, namely, detectors, morphological operators and modulators. The detectors and operators are fabricated on a silicon VLSI chip and implement the optical input and morphological operations. A layer of ferro-electric liquid crystals is integrated with a silicon chip to provide the optical modulation. The implementation of the image processing operators in electronics leads to a wide range of applications and the use of optical connections allows cascadability of these parallel opto-electronic image processing components and high speed operation. Such an opto-electronic morphological processor may be used as the pre-processing stage in an image recognition system. In one example disclosed herein, the optical input/optical output morphological processor of the invention is interfaced with a binary phase-only correlator to produce an image recognition system.

  7. PIXEL PUSHER

    NASA Technical Reports Server (NTRS)

    Stanfill, D. F.

    1994-01-01

    Pixel Pusher is a Macintosh application used for viewing and performing minor enhancements on imagery. It will read image files in JPL's two primary image formats- VICAR and PDS - as well as the Macintosh PICT format. VICAR (NPO-18076) handles an array of image processing capabilities which may be used for a variety of applications including biomedical image processing, cartography, earth resources, and geological exploration. Pixel Pusher can also import VICAR format color lookup tables for viewing images in pseudocolor (256 colors). This program currently supports only eight bit images but will work on monitors with any number of colors. Arbitrarily large image files may be viewed in a normal Macintosh window. Color and contrast enhancement can be performed with a graphical "stretch" editor (as in contrast stretch). In addition, VICAR images may be saved as Macintosh PICT files for exporting into other Macintosh programs, and individual pixels can be queried to determine their locations and actual data values. Pixel Pusher is written in Symantec's Think C and was developed for use on a Macintosh SE30, LC, or II series computer running System Software 6.0.3 or later and 32 bit QuickDraw. Pixel Pusher will only run on a Macintosh which supports color (whether a color monitor is being used or not). The standard distribution medium for this program is a set of three 3.5 inch Macintosh format diskettes. The program price includes documentation. Pixel Pusher was developed in 1991 and is a copyrighted work with all copyright vested in NASA. Think C is a trademark of Symantec Corporation. Macintosh is a registered trademark of Apple Computer, Inc.

  8. Opto-mechano-fluidic viscometer

    SciTech Connect

    Han, Kewen Zhu, Kaiyuan; Bahl, Gaurav

    2014-07-07

    The recent development of opto-mechano-fluidic resonators has provided—by harnessing photon radiation pressure—a microfluidics platform for the optical sensing of fluid density and bulk modulus. Here, we show that fluid viscosity can also be determined through optomechanical measurement of the vibrational noise spectrum of the resonator mechanical modes. A linear relationship between the spectral linewidth and root-viscosity is predicted and experimentally verified in the low viscosity regime. Our result is a step towards multi-frequency measurement of viscoelasticity of arbitrary fluids, without sample contamination, using highly sensitive optomechanics techniques.

  9. Opto-acoustic cell permeation

    SciTech Connect

    Visuri, S R; Heredia, N

    2000-03-09

    Optically generated acoustic waves have been used to temporarily permeate biological cells. This technique may be useful for enhancing transfection of DNA into cells or enhancing the absorption of locally delivered drugs. A diode-pumped frequency-doubled Nd:YAG laser operating at kHz repetition rates was used to produce a series of acoustic pulses. An acoustic wave was formed via thermoelastic expansion by depositing laser radiation into an absorbing dye. Generated pressures were measured with a PVDF hydrophone. The acoustic waves were transmitted to cultured and plated cells. The cell media contained a selection of normally- impermeable fluorescent-labeled dextran dyes. Following treatment with the opto-acoustic technique, cellular incorporation of dyes, up to 40,000 Molecular Weight, was noted. Control cells that did not receive opto-acoustic treatment had unremarkable dye incorporation. Uptake of dye was quantified via fluorescent microscopic analysis. Trypan Blue membrane exclusion assays and fluorescent labeling assays confirmed the vitality of cells following treatment. This method of enhanced drug delivery has the potential to dramatically reduce required drug dosages and associated side effects and enable revolutionary therapies.

  10. Opto-Electronic Oscillator and its Applications

    NASA Technical Reports Server (NTRS)

    Yao, X. S.; Maleki, L.

    1996-01-01

    We present the theoretical and experimental results of a new class of microwave oscillators called opto-electronic oscillators (OEO). We discuss techniques of achieving high stability single mode operation and demonstrate the applications of OEO in photonic communication systems.

  11. Pixel Perfect

    SciTech Connect

    Perrine, Kenneth A.; Hopkins, Derek F.; Lamarche, Brian L.; Sowa, Marianne B.

    2005-09-01

    cubic warp. During image acquisitions, the cubic warp is evaluated by way of forward differencing. Unwanted pixelation artifacts are minimized by bilinear sampling. The resulting system is state-of-the-art for biological imaging. Precisely registered images enable the reliable use of FRET techniques. In addition, real-time image processing performance allows computed images to be fed back and displayed to scientists immediately, and the pipelined nature of the FPGA allows additional image processing algorithms to be incorporated into the system without slowing throughput.

  12. Structured detailed opto-mechanical tolerance modeling

    NASA Astrophysics Data System (ADS)

    Swart, P. C.

    2016-02-01

    Opto-mechanical tolerancing is a complex art, which is often reduced to inadequate tabled data of allowable tilts and decentres. During the process the respective roles of optical- and mechanical designers can become entangled and a source of conflict. A framework of principles is introduced to guide the design team through these murky waters. From these principles the development of a catalogue of models, practices and past precedents are proposed. An example is presented to serve as illustration. The final result is a model, of opto-mechanical tolerances, which allows a structured flow of tolerances into optical performance prediction.

  13. Opto-electronic oscillators having optical resonators

    NASA Technical Reports Server (NTRS)

    Yao, Xiaotian Steve (Inventor); Maleki, Lutfollah (Inventor); Ilchenko, Vladimir (Inventor)

    2003-01-01

    Systems and techniques of incorporating an optical resonator in an optical part of a feedback loop in opto-electronic oscillators. This optical resonator provides a sufficiently long energy storage time and hence to produce an oscillation of a narrow linewidth and low phase noise. Certain mode matching conditions are required. For example, the mode spacing of the optical resonator is equal to one mode spacing, or a multiplicity of the mode spacing, of an opto-electronic feedback loop that receives a modulated optical signal and to produce an electrical oscillating signal.

  14. Optical and opto-acoustic interventional imaging.

    PubMed

    Sarantopoulos, Athanasios; Beziere, Nicolas; Ntziachristos, Vasilis

    2012-02-01

    Many clinical interventional procedures, such as surgery or endoscopy, are today still guided by human vision and perception. Human vision however is not sensitive or accurate in detecting a large range of disease biomarkers, for example cellular or molecular processes characteristic of disease. For this reason advanced optical and opto-acoustic (photo-acoustic) methods are considered for enabling a more versatile, sensitive and accurate detection of disease biomarkers and complement human vision in clinical decision making during interventions. Herein, we outline developments in emerging fluorescence and opto-acoustic sensing and imaging techniques that can lead to practical implementations toward improving interventional vision.

  15. Opto-Electronic Characterization CdTe Solar Cells from TCO to Back Contact with Nano-Scale CL Probe

    SciTech Connect

    Moseley, John; Al-Jassim, Mowafak M.; Paudel, Naba; Mahabaduge, Hasitha; Kuciauskas, Darius; Guthrey, Harvey L.; Duenow, Joel; Yan, Yanfa; Metzger, Wyatt K.; Ahrenkiel, Richard K.

    2015-06-14

    We used cathodoluminescence (CL) (spectrum-per-pixel) imaging on beveled CdTe solar cell sections to investigate the opto-electronic properties of these devices from the TCO to the back contact. We used a nano-scale CL probe to resolve luminescence from grain boundary (GB) and grain interior (GI) locations near the CdS/CdTe interface where the grains are very small. As-deposited, CdCl2-treated, Cu-treated, and (CdCl2+Cu)-treated cells were analyzed. Color-coded CL spectrum imaging maps on bevels illustrate the distribution of the T=6 K luminescence transitions through the depth of devices with unprecedented spatial resolution. The CL at the GBs and GIs is shown to vary significantly from the front to the back of devices and is a sensitive function of processing. Supporting D-SIMS depth profile, TRPL lifetime, and C-V measurements are used to link the CL data to the J-V performance of devices.

  16. Opto-electrokinetic manipulation technique for highperformance

    SciTech Connect

    Kwon, Jae-Sung; Ravindranath, Sandeep; Kumar, Aloke; Irudayaraj, Joseph; Wereley, Steven T.

    2012-01-01

    This communication first demonstrates bio-compatibility of a recently developed opto-electrokinetic manipulation technique, using microorganisms. Aggregation, patterning, translation, trapping and size-based separation of microorganisms performed with the technique firmly establishes its usefulness for development of a high-performance on-chip bioassay system.

  17. Electrical power consumption of the emitter for a non-guided optoelectronic link Optimisation de la consommation électrique d'un émetteur pour une liaison optoélectronique non-guidée

    NASA Astrophysics Data System (ADS)

    Benaouda, A.; Lescure, M.; Bensalah, R.

    1998-02-01

    The aim of this paper is to determine the best value of the signal-to-noise ratio (SNR) for a non-guided optoelectronic link with minimum electrical power consumption by the emitter. Transmitter structures have been analysed and optimized as a function of the bit error rate (BER) of the link in order to give either the highest autonomy or a lower number of emitter components. The application requirement for the transmitter is consequently to offer a flexible and secure communication solution. The transmitter provides non-guided infrared communication inside a limited cell size. The thermal effects, the rise and fall times of the optical power output of the emission and the characteristics of component devices have been taken into consideration in order to evaluate the SNR. We demonstrate that, for a given electrical consumption, the emitted optical power of the transmitter circuit increases with the logarithm of the total number of light emitting diodes.

  18. ATLAS IBL Pixel Upgrade

    NASA Astrophysics Data System (ADS)

    La Rosa, A.; Atlas Ibl Collaboration

    2011-06-01

    The upgrade for ATLAS detector will undergo different phases towards super-LHC. The first upgrade for the Pixel detector will consist of the construction of a new pixel layer which will be installed during the first shutdown of the LHC machine (LHC phase-I upgrade). The new detector, called Insertable B-Layer (IBL), will be inserted between the existing pixel detector and a new (smaller radius) beam-pipe at a radius of 3.3 cm. The IBL will require the development of several new technologies to cope with increase of radiation or pixel occupancy and also to improve the physics performance which will be achieved by reducing the pixel size and of the material budget. Three different promising sensor technologies (planar-Si, 3D-Si and diamond) are currently under investigation for the pixel detector. An overview of the project with particular emphasis on the pixel module is presented in this paper.

  19. Bad pixel mapping

    NASA Astrophysics Data System (ADS)

    Smith, Roger M.; Hale, David; Wizinowich, Peter

    2014-07-01

    Bad pixels are generally treated as a loss of useable area and then excluded from averaged performance metrics. The definition and detection of "bad pixels" or "cosmetic defects" are seldom discussed, perhaps because they are considered self-evident or of minor consequence for any scientific grade detector, however the ramifications can be more serious than generally appreciated. While the definition of pixel performance is generally understood, the classification of pixels as useable is highly application-specific, as are the consequences of ignoring or interpolating over such pixels. CMOS sensors (including NIR detectors) exhibit less compact distributions of pixel properties than CCDs. The extended tails in these distributions result in a steeper increase in bad pixel counts as performance thresholds are tightened which comes as a surprise to many users. To illustrate how some applications are much more sensitive to bad pixels than others, we present a bad pixel mapping exercise for the Teledyne H2RG used as the NIR tip-tilt sensor in the Keck-1 Adaptive Optics system. We use this example to illustrate the wide range of metrics by which a pixel might be judged inadequate. These include pixel bump bond connectivity, vignetting, addressing faults in the mux, severe sensitivity deficiency of some pixels, non linearity, poor signal linearity, low full well, poor mean-variance linearity, excessive noise and high dark current. Some pixels appear bad by multiple metrics. We also discuss the importance of distinguishing true performance outliers from measurement errors. We note how the complexity of these issues has ramifications for sensor procurement and acceptance testing strategies.

  20. Integrated waveguide-DBR microcavity opto-mechanical system.

    PubMed

    Pruessner, Marcel W; Stievater, Todd H; Khurgin, Jacob B; Rabinovich, William S

    2011-10-24

    Cavity opto-mechanics exploits optical forces acting on mechanical structures. Many opto-mechanics demonstrations either require extensive alignment of optical components for probing and measurement, which limits the number of opto-mechanical devices on-chip; or the approaches limit the ability to control the opto-mechanical parameters independently. In this work, we propose an opto-mechanical architecture incorporating a waveguide-DBR microcavity coupled to an in-plane micro-bridge resonator, enabling large-scale integration on-chip with the ability to individually tune the optical and mechanical designs. We experimentally characterize our device and demonstrate mechanical resonance damping and amplification, including the onset of coherent oscillations. The resulting collapse of the resonance linewidth implies a strong increase in effective mechanical quality-factor, which is of interest for high-resolution sensing.

  1. PixelLearn

    NASA Technical Reports Server (NTRS)

    Mazzoni, Dominic; Wagstaff, Kiri; Bornstein, Benjamin; Tang, Nghia; Roden, Joseph

    2006-01-01

    PixelLearn is an integrated user-interface computer program for classifying pixels in scientific images. Heretofore, training a machine-learning algorithm to classify pixels in images has been tedious and difficult. PixelLearn provides a graphical user interface that makes it faster and more intuitive, leading to more interactive exploration of image data sets. PixelLearn also provides image-enhancement controls to make it easier to see subtle details in images. PixelLearn opens images or sets of images in a variety of common scientific file formats and enables the user to interact with several supervised or unsupervised machine-learning pixel-classifying algorithms while the user continues to browse through the images. The machinelearning algorithms in PixelLearn use advanced clustering and classification methods that enable accuracy much higher than is achievable by most other software previously available for this purpose. PixelLearn is written in portable C++ and runs natively on computers running Linux, Windows, or Mac OS X.

  2. An Opto-MEMS Multiobject Spectrograph

    NASA Astrophysics Data System (ADS)

    Kearney, K.; Ninkov, Z.; Zwarg, D.

    2000-05-01

    Optical MEMS (Micro-Electro-Mechanical-Structures) are an enabling technology for a new class of optical instrumentation designs. An opto-MEMS device consists of an array of microfabricated structures, each of which modulates the phase and/or amplitude of an incident light beam. Typically the devices consist of an array of moveable micromirrors - each of which reflects an incident beam in a unique direction (tilt), or with a unique phase shift (piston). One widely available opto-MEMS device is the Texas Instruments' Digital Micromirror Device (DMD). The DMD is an array of 16 micron x 16 micron square mirrors postioned on a 17 micron pitch. Each mirror can tilt +/- 10 degrees from the normal - reflecting a normally incident light beam +/- 20 degrees. By positioning the DMD in an intermediate image plane in an optical system, portions of the image can be directed into- or out-of the input pupil of the follow-on imaging optics. RIT is utilizing the DMD to construct a prototype multiobject spectrograph (RIT-MOS) for visible observations with terrestrial telescopes. The DMD array replaces the input slit of an imaging spectrograph, forming a 'virtual', programmable slit assembly. By acquiring a pre-image of the astronomical field, it is possible to select a multidude of objects, and to program the DMD to pass only those objects into the input optics of the imaging spectrograph. We will report on the design and characterizatotion of the RIT-MOS, as well as preliminary imaging results.

  3. Considerations for opto-mechanical vs. digital stabilization in surveillance systems

    NASA Astrophysics Data System (ADS)

    Kowal, David

    2015-05-01

    Electro-optical surveillance and reconnaissance systems are frequently mounted on unstable or vibrating platforms such as ships, vehicles, aircraft and masts. Mechanical coupling between the platform and the cameras leads to angular vibration of the line of sight. Image motion during detector and eye integration times leads to image smear and a resulting loss of resolution. Additional effects are wavy images for detectors based on a rolling shutter mechanism and annoying movement of the image at low frequencies. A good stabilization system should yield sub-pixel stabilization errors and meet cost and size requirements. There are two main families of LOS stabilization methods: opto-mechanical stabilization and electronic stabilization. Each family, or a combination of both, can be implemented by a number of different techniques of varying complexity, size and cost leading to different levels of stabilization. Opto-mechanical stabilization is typically based on gyro readings, whereas electronic stabilization is typically based on gyro readings or image registration calculations. A few common stabilization techniques, as well as options for different gimbal arrangements will be described and analyzed. The relative merits and drawbacks of the different techniques and their applicability to specific systems and environments will be discussed. Over the years Controp has developed a large number of stabilized electro-optical payloads. A few examples of payloads with unique stabilization mechanisms will be described.

  4. An Opto-Thermocapillary Cell Micromanipulator

    PubMed Central

    Fan, Qihui; Ohta, Aaron T.

    2013-01-01

    An opto-thermocapillary micromanipulator (OTMm) capable of single-cell manipulation and patterning is presented here. The OTMm uses a near-infrared laser focused on an ITO substrate to induce thermocapillary convection that can trap and transport living cells with forces of up to 40 pN. The OTMm complements other cell-manipulation technologies such as optical tweezers and dielectrophoresis, as it is less dependent upon the optical and electrical properties of the working environment, and can function in many types of cell culture media. The OTMm was used to construct single-cell matrices in two popular hydrogels: PEGDA and agarose. High viability rates were observed in both hydrogels, and cells patterned in agarose spread and migrated during subsequent culturing. PMID:23666050

  5. High density pixel array

    NASA Technical Reports Server (NTRS)

    Wiener-Avnear, Eliezer (Inventor); McFall, James Earl (Inventor)

    2004-01-01

    A pixel array device is fabricated by a laser micro-milling method under strict process control conditions. The device has an array of pixels bonded together with an adhesive filling the grooves between adjacent pixels. The array is fabricated by moving a substrate relative to a laser beam of predetermined intensity at a controlled, constant velocity along a predetermined path defining a set of grooves between adjacent pixels so that a predetermined laser flux per unit area is applied to the material, and repeating the movement for a plurality of passes of the laser beam until the grooves are ablated to a desired depth. The substrate is of an ultrasonic transducer material in one example for fabrication of a 2D ultrasonic phase array transducer. A substrate of phosphor material is used to fabricate an X-ray focal plane array detector.

  6. Fiber pixelated image database

    NASA Astrophysics Data System (ADS)

    Shinde, Anant; Perinchery, Sandeep Menon; Matham, Murukeshan Vadakke

    2016-08-01

    Imaging of physically inaccessible parts of the body such as the colon at micron-level resolution is highly important in diagnostic medical imaging. Though flexible endoscopes based on the imaging fiber bundle are used for such diagnostic procedures, their inherent honeycomb-like structure creates fiber pixelation effects. This impedes the observer from perceiving the information from an image captured and hinders the direct use of image processing and machine intelligence techniques on the recorded signal. Significant efforts have been made by researchers in the recent past in the development and implementation of pixelation removal techniques. However, researchers have often used their own set of images without making source data available which subdued their usage and adaptability universally. A database of pixelated images is the current requirement to meet the growing diagnostic needs in the healthcare arena. An innovative fiber pixelated image database is presented, which consists of pixelated images that are synthetically generated and experimentally acquired. Sample space encompasses test patterns of different scales, sizes, and shapes. It is envisaged that this proposed database will alleviate the current limitations associated with relevant research and development and would be of great help for researchers working on comb structure removal algorithms.

  7. Opto-mechanical door locking system

    NASA Astrophysics Data System (ADS)

    Patil, Saurabh S.; Rodrigues, Vanessa M.; Patil, Ajeetkumar; Chidangil, Santhosh

    2015-09-01

    We present an Opto-mechanical Door Locking System which is an optical system that combines a simple combination of a coherent light source (Laser) and a photodiode based sensor with focus toward security applications. The basic construct of the KEY comprises a Laser source in a cylindrical enclosure that slides perfectly into the LOCK. The Laser is pulsed at a fixed encrypted frequency unique to that locking system. Transistor-transistor logic (TTL) circuitry is used to achieve encryption. The casing of the key is designed in such a way that it will power the pulsing laser only when the key is inserted in the slot provided for it. The Lock includes a photo-sensor that will convert the detected light intensity to a corresponding electrical signal by decrypting the frequency. The lock also consists of a circuit with a feedback system that will carry the digital information regarding the encryption frequency code. The information received from the sensor is matched with the stored code; if found a perfect match, a signal will be sent to the servo to unlock the mechanical lock or to carry out any other operation. This technique can be incorporated in security systems for residences and safe houses, and can easily replace all conventional locks which formerly used fixed patterns to unlock. The major advantage of this proposed optomechanical system over conventional ones is that it no longer relies on a solid/imprinted pattern to perform its task and hence makes it almost impossible to tamper with.

  8. Selecting Pixels for Kepler Downlink

    NASA Technical Reports Server (NTRS)

    Bryson, Stephen T.; Jenkins, Jon M.; Klaus, Todd C.; Cote, Miles T.; Quintana, Elisa V.; Hall, Jennifer R.; Ibrahim, Khadeejah; Chandrasekaran, Hema; Caldwell, Douglas A.; Van Cleve, Jeffrey E.; Haas, Michael R.

    2010-01-01

    The Kepler mission monitors > 100,000 stellar targets using 42 2200 1024 pixel CCDs. Bandwidth constraints prevent the downlink of all 96 million pixels per 30-minute cadence, so the Kepler spacecraft downlinks a specified collection of pixels for each target. These pixels are selected by considering the object brightness, background and the signal-to-noise of each pixel, and are optimized to maximize the signal-to-noise ratio of the target. This paper describes pixel selection, creation of spacecraft apertures that efficiently capture selected pixels, and aperture assignment to a target. Diagnostic apertures, short-cadence targets and custom specified shapes are discussed.

  9. Laser-induced damage threshold of camera sensors and micro-opto-electro-mechanical systems

    NASA Astrophysics Data System (ADS)

    Schwarz, Bastian; Ritt, Gunnar; Körber, Michael; Eberle, Bernd

    2016-10-01

    The continuous development of laser systems towards more compact and efficient devices constitutes an increasing threat to electro-optical imaging sensors such as complementary metal-oxide-semiconductors (CMOS) and charge-coupled devices (CCD). These types of electronic sensors are used in day-to-day life but also in military or civil security applications. In camera systems dedicated to specific tasks, also micro-opto-electro-mechanical systems (MOEMS) like a digital micromirror device (DMD) are part of the optical setup. In such systems, the DMD can be located at an intermediate focal plane of the optics and it is also susceptible to laser damage. The goal of our work is to enhance the knowledge of damaging effects on such devices exposed to laser light. The experimental setup for the investigation of laser-induced damage is described in detail. As laser sources both pulsed lasers and continuous-wave (CW) lasers are used. The laser-induced damage threshold (LIDT) is determined by the single-shot method by increasing the pulse energy from pulse to pulse or in the case of CW-lasers, by increasing the laser power. Furthermore, we investigate the morphology of laser-induced damage patterns and the dependence of the number of destructed device elements on the laser pulse energy or laser power. In addition to the destruction of single pixels, we observe aftereffects like persisting dead columns or rows of pixels in the sensor image.

  10. Opto-nanomechanical spectroscopic material characterization

    SciTech Connect

    Tetard, Laurene; Passian, Ali; Farahi, R. H.; Thundat, Thomas; Davison, Brian H.

    2015-08-10

    Cellulosic ethanol is a biofuel of considerable potential in the search for sustainable and renewable bioenergy [1,2]. However, while rich in carbohydrates [3], the plant cell walls exhibit a natural resistance to complex phenotype treatments such as enzymatic microbial deconstruction, heat and acid treatments that can remove the lignin polymers from cellulose before hydrolysis [5]. Noninvasive physical and chemical characterization of the cell walls and the effect of such treatments on biomass are challenging but necessary to understand and overcome such resistance [6]. Although lacking chemical recognition in their traditional forms, the various emerging modalities of nano-mechanical [7] and opto-nano-mechanical [8] force microscopies [9,10] provide a superb window into the needed nanoscale material characterization [6]. Infrared absorption spectroscopy is a powerful, non- destructive and ultra-sensitive technique that can provide the needed molecular fingerprinting but the photothermal channel is delocalized and thus lacks spatial resolution. Utilizing the emerging dynamic concepts of mode synthesizing atomic force microscopy (MSAFM) [11] and virtual resonance [12], we introduce a hybrid photonic and nanomechanical force microscopy (hp-MSAFM) with molecular recognition and characterize the extraction, holopulping and acid treatment of biomass. We present spatially and spectrally resolved cell wall images that reveal both the morphological and the compositional alterations of the cell walls. The measured biomolecular traits are in agreement with chemical maps obtained with infrared and confocal Raman micro-spectroscopies of the same samples. The presented findings should prove highly relevant in fields such as cancer research [13], nanotoxicity [14], energy storage and production [15], where morphological, chemical and subsurface studies of nanocomposites [16], nanoparticle uptake by cells [14], and nanoscale quality control [17] are in demand.

  11. Opto-nanomechanical spectroscopic material characterization

    DOE PAGES

    Tetard, Laurene; Passian, Ali; Farahi, R. H.; ...

    2015-08-10

    Cellulosic ethanol is a biofuel of considerable potential in the search for sustainable and renewable bioenergy [1,2]. However, while rich in carbohydrates [3], the plant cell walls exhibit a natural resistance to complex phenotype treatments such as enzymatic microbial deconstruction, heat and acid treatments that can remove the lignin polymers from cellulose before hydrolysis [5]. Noninvasive physical and chemical characterization of the cell walls and the effect of such treatments on biomass are challenging but necessary to understand and overcome such resistance [6]. Although lacking chemical recognition in their traditional forms, the various emerging modalities of nano-mechanical [7] and opto-nano-mechanicalmore » [8] force microscopies [9,10] provide a superb window into the needed nanoscale material characterization [6]. Infrared absorption spectroscopy is a powerful, non- destructive and ultra-sensitive technique that can provide the needed molecular fingerprinting but the photothermal channel is delocalized and thus lacks spatial resolution. Utilizing the emerging dynamic concepts of mode synthesizing atomic force microscopy (MSAFM) [11] and virtual resonance [12], we introduce a hybrid photonic and nanomechanical force microscopy (hp-MSAFM) with molecular recognition and characterize the extraction, holopulping and acid treatment of biomass. We present spatially and spectrally resolved cell wall images that reveal both the morphological and the compositional alterations of the cell walls. The measured biomolecular traits are in agreement with chemical maps obtained with infrared and confocal Raman micro-spectroscopies of the same samples. The presented findings should prove highly relevant in fields such as cancer research [13], nanotoxicity [14], energy storage and production [15], where morphological, chemical and subsurface studies of nanocomposites [16], nanoparticle uptake by cells [14], and nanoscale quality control [17] are in demand.« less

  12. Spatially resolved imaging of opto-electrical property variations

    DOEpatents

    Nikiforov, Maxim; Darling, Seth B; Suzer, Ozgun; Guest, Jeffrey; Roelofs, Andreas

    2014-09-16

    Systems and methods for opto electric properties are provided. A light source illuminates a sample. A reference detector senses light from the light source. A sample detector receives light from the sample. A positioning fixture allows for relative positioning of the sample or the light source with respect to each other. An electrical signal device measures the electrical properties of the sample. The reference detector, sample detector and electrical signal device provide information that may be processed to determine opto-electric properties of the same.

  13. Hybrid opto-electric manipulation in microfluidics - opportunities and challenges

    SciTech Connect

    Kumar, Aloke; Williams, Stuart J.; Chuang, Han-sheng; Green, Nicolas; Wereley, Steven G.

    2011-01-01

    Hybrid opto-electric manipulation in microfluidics/nanofluidics refers to a set of technologies that employ both optical and electrical forces to achieve particle or fluid manipulation at the micro and nano scale. These technologies, which have emerged primarily over the last decade, have provided a revolutionary and fresh perspective at fundamental electrokinetic processes, as well as have engendered a novel applications and devices. Hybrid opto-electric techniques have been utilized to manipulate objects ranging in diversity from millimeter-sized droplets to nano-particles. This review article discusses the underlying principles, applications and future perspectives of various techniques that have emerged over the last decade under a unified umbrella.

  14. Magnetometer Based on the Opto-Electronic Oscillator

    NASA Technical Reports Server (NTRS)

    Matsko, Andrey B.; Strekalov, Dmitry; Maleki, Lute

    2005-01-01

    We theoretically propose and discuss properties of two schemes of an all-optical self-oscillating magnetometer based on an opto-electronic oscillator stabilized with an atomic vapor cell. Proof of the principle DC magnetic field measurements characterized with 2 x 10(exp -7) G sensitivity and 1 - 1000 mG dynamic range in one of the schemes are demonstrated.

  15. Photovoltaic Devices: Opto-Electro-Thermal Physics and Modeling.

    PubMed

    Shang, Aixue; Li, Xiaofeng

    2017-02-01

    An opto-electro-thermal simulation of solar cells (SCs) is presented by addressing optoelectronic and thermodynamic responses simultaneously. The photocurrent losses due to carrier recombinations and the intrinsic heat generation (thermalization/Joule/Peltier/recombination heat) and dissipation (convective/radiative cooling) processes in the SCs are investigated quantitatively.

  16. Opto-mechanical assembly procurement for the National Ignition Facility

    SciTech Connect

    House, W; Simon, T

    1999-07-01

    A large number of the small optics procurements for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) will be in the form of completely assembled, tested, and cleaned subsystems. These subsystems will be integrated into the NIF at LLNL. To accomplish this task, the procurement packages will include, optical and mechanical drawings, acceptance test and cleanliness requirements. In January 1999, the first such integrated opto-mechanical assembly was received and evaluated at LLNL. With the successful completion of this important trial procurement, we were able to establish the viability of purchasing clean, ready to install, opto-mechanical assemblies from vendors within the optics industry. 32 vendors were chosen from our supplier database for quote, then five were chosen to purchase from. These five vendors represented a cross section of the optics industry. From a ''value'' catalog supplier (that did the whole job internally) to a partnership between three specialty companies, these vendors demonstrated they have the ingenuity and capability to deliver cost competitive, NIF-ready, opto- mechanical assemblies. This paper describes the vendor selection for this procurement, technical requirements including packaging, fabrication, coating, and cleanliness specifications, then testing and verification. It also gives real test results gathered from inspections performed at LLNL that show how our vendors scored on the various requirements. Keywords: Opto-Mechanical, assembly, NIF, packaging, shipping, specifications, procurement, MIL-STD-1246C, surface cleanliness

  17. New Results with the Opto-Electronic Oscillators (OEO)

    NASA Technical Reports Server (NTRS)

    Yao, S.; Maleki, L.

    1996-01-01

    A new class of oscillators based on photonic devices is presented. These opto-electronic oscillators (OEOs) generate microwave oscillation by converting continuous energy from a light source using a feedback circuit which includes a delay element, an electro-optic switch, and a photodetctor.

  18. Pixelated neutron image plates

    NASA Astrophysics Data System (ADS)

    Schlapp, M.; Conrad, H.; von Seggern, H.

    2004-09-01

    Neutron image plates (NIPs) have found widespread application as neutron detectors for single-crystal and powder diffraction, small-angle scattering and tomography. After neutron exposure, the image plate can be read out by scanning with a laser. Commercially available NIPs consist of a powder mixture of BaFBr : Eu2+ and Gd2O3 dispersed in a polymer matrix and supported by a flexible polymer sheet. Since BaFBr : Eu2+ is an excellent x-ray storage phosphor, these NIPs are particularly sensitive to ggr-radiation, which is always present as a background radiation in neutron experiments. In this work we present results on NIPs consisting of KCl : Eu2+ and LiF that were fabricated into ceramic image plates in which the alkali halides act as a self-supporting matrix without the necessity for using a polymeric binder. An advantage of this type of NIP is the significantly reduced ggr-sensitivity. However, the much lower neutron absorption cross section of LiF compared with Gd2O3 demands a thicker image plate for obtaining comparable neutron absorption. The greater thickness of the NIP inevitably leads to a loss in spatial resolution of the image plate. However, this reduction in resolution can be restricted by a novel image plate concept in which a ceramic structure with square cells (referred to as a 'honeycomb') is embedded in the NIP, resulting in a pixelated image plate. In such a NIP the read-out light is confined to the particular illuminated pixel, decoupling the spatial resolution from the optical properties of the image plate material and morphology. In this work, a comparison of experimentally determined and simulated spatial resolutions of pixelated and unstructured image plates for a fixed read-out laser intensity is presented, as well as simulations of the properties of these NIPs at higher laser powers.

  19. The ALICE Pixel Detector

    NASA Astrophysics Data System (ADS)

    Mercado-Perez, Jorge

    2002-07-01

    The present document is a brief summary of the performed activities during the 2001 Summer Student Programme at CERN under the Scientific Summer at Foreign Laboratories Program organized by the Particles and Fields Division of the Mexican Physical Society (Sociedad Mexicana de Fisica). In this case, the activities were related with the ALICE Pixel Group of the EP-AIT Division, under the supervision of Jeroen van Hunen, research fellow in this group. First, I give an introduction and overview to the ALICE experiment; followed by a description of wafer probing. A brief summary of the test beam that we had from July 13th to July 25th is given as well.

  20. Pixel electronics for the ATLAS experiment

    NASA Astrophysics Data System (ADS)

    Fischer, P.

    2001-06-01

    The ATLAS experiment at LHC will use 3 barrel layers and 2×5 disks of silicon pixel detectors as the innermost elements of the semiconductor tracker. The basic building blocks are pixel modules with an active area of 16.4 mm×60.8 mm which include an n + on n-type silicon sensor and 16 VLSI front-end (FE) chips. Every FE chip contains a low power, high speed charge sensitive preamplifier, a fast discriminator, and a readout system which operates at the 40 MHz rate of LHC. The addresses of hit pixels (as well as a low resolution pulse height information) are stored on the FE chips until arrival of a level 1 trigger signal. Hits are then transferred to a module controller chip (MCC) which collects the data of all 16 FE chips, builds complete events and sends the data through two optical links to the data acquisition system. The MCC receives clock and data through an additional optical link and provides timing and configuration information for the FE chips. Two additional chips are used to amplify and decode the pin diode signal and to drive the VCSEL laser diodes of the optical links.

  1. All-passive pixel super-resolution of time-stretch imaging

    PubMed Central

    Chan, Antony C. S.; Ng, Ho-Cheung; Bogaraju, Sharat C. V.; So, Hayden K. H.; Lam, Edmund Y.; Tsia, Kevin K.

    2017-01-01

    Based on image encoding in a serial-temporal format, optical time-stretch imaging entails a stringent requirement of state-of-the-art fast data acquisition unit in order to preserve high image resolution at an ultrahigh frame rate — hampering the widespread utilities of such technology. Here, we propose a pixel super-resolution (pixel-SR) technique tailored for time-stretch imaging that preserves pixel resolution at a relaxed sampling rate. It harnesses the subpixel shifts between image frames inherently introduced by asynchronous digital sampling of the continuous time-stretch imaging process. Precise pixel registration is thus accomplished without any active opto-mechanical subpixel-shift control or other additional hardware. Here, we present the experimental pixel-SR image reconstruction pipeline that restores high-resolution time-stretch images of microparticles and biological cells (phytoplankton) at a relaxed sampling rate (≈2–5 GSa/s)—more than four times lower than the originally required readout rate (20 GSa/s) — is thus effective for high-throughput label-free, morphology-based cellular classification down to single-cell precision. Upon integration with the high-throughput image processing technology, this pixel-SR time-stretch imaging technique represents a cost-effective and practical solution for large scale cell-based phenotypic screening in biomedical diagnosis and machine vision for quality control in manufacturing. PMID:28303936

  2. All-passive pixel super-resolution of time-stretch imaging

    NASA Astrophysics Data System (ADS)

    Chan, Antony C. S.; Ng, Ho-Cheung; Bogaraju, Sharat C. V.; So, Hayden K. H.; Lam, Edmund Y.; Tsia, Kevin K.

    2017-03-01

    Based on image encoding in a serial-temporal format, optical time-stretch imaging entails a stringent requirement of state-of-the-art fast data acquisition unit in order to preserve high image resolution at an ultrahigh frame rate — hampering the widespread utilities of such technology. Here, we propose a pixel super-resolution (pixel-SR) technique tailored for time-stretch imaging that preserves pixel resolution at a relaxed sampling rate. It harnesses the subpixel shifts between image frames inherently introduced by asynchronous digital sampling of the continuous time-stretch imaging process. Precise pixel registration is thus accomplished without any active opto-mechanical subpixel-shift control or other additional hardware. Here, we present the experimental pixel-SR image reconstruction pipeline that restores high-resolution time-stretch images of microparticles and biological cells (phytoplankton) at a relaxed sampling rate (≈2–5 GSa/s)—more than four times lower than the originally required readout rate (20 GSa/s) — is thus effective for high-throughput label-free, morphology-based cellular classification down to single-cell precision. Upon integration with the high-throughput image processing technology, this pixel-SR time-stretch imaging technique represents a cost-effective and practical solution for large scale cell-based phenotypic screening in biomedical diagnosis and machine vision for quality control in manufacturing.

  3. Imaging properties of pixellated scintillators with deep pixels

    PubMed Central

    Barber, H. Bradford; Fastje, David; Lemieux, Daniel; Grim, Gary P.; Furenlid, Lars R.; Miller, Brian W.; Parkhurst, Philip; Nagarkar, Vivek V.

    2015-01-01

    We have investigated the light-transport properties of scintillator arrays with long, thin pixels (deep pixels) for use in high-energy gamma-ray imaging. We compared 10×10 pixel arrays of YSO:Ce, LYSO:Ce and BGO (1mm × 1mm × 20 mm pixels) made by Proteus, Inc. with similar 10×10 arrays of LSO:Ce and BGO (1mm × 1mm × 15mm pixels) loaned to us by Saint-Gobain. The imaging and spectroscopic behaviors of these scintillator arrays are strongly affected by the choice of a reflector used as an inter-pixel spacer (3M ESR in the case of the Proteus arrays and white, diffuse-reflector for the Saint-Gobain arrays). We have constructed a 3700-pixel LYSO:Ce Prototype NIF Gamma-Ray Imager for use in diagnosing target compression in inertial confinement fusion. This system was tested at the OMEGA Laser and exhibited significant optical, inter-pixel cross-talk that was traced to the use of a single-layer of ESR film as an inter-pixel spacer. We show how the optical cross-talk can be mapped, and discuss correction procedures. We demonstrate a 10×10 YSO:Ce array as part of an iQID (formerly BazookaSPECT) imager and discuss issues related to the internal activity of 176Lu in LSO:Ce and LYSO:Ce detectors. PMID:26236070

  4. Imaging properties of pixellated scintillators with deep pixels

    NASA Astrophysics Data System (ADS)

    Barber, H. Bradford; Fastje, David; Lemieux, Daniel; Grim, Gary P.; Furenlid, Lars R.; Miller, Brian W.; Parkhurst, Philip; Nagarkar, Vivek V.

    2014-09-01

    We have investigated the light-transport properties of scintillator arrays with long, thin pixels (deep pixels) for use in high-energy gamma-ray imaging. We compared 10x10 pixel arrays of YSO:Ce, LYSO:Ce and BGO (1mm x 1mm x 20 mm pixels) made by Proteus, Inc. with similar 10x10 arrays of LSO:Ce and BGO (1mm x 1mm x 15mm pixels) loaned to us by Saint-Gobain. The imaging and spectroscopic behaviors of these scintillator arrays are strongly affected by the choice of a reflector used as an inter-pixel spacer (3M ESR in the case of the Proteus arrays and white, diffuse-reflector for the Saint-Gobain arrays). We have constructed a 3700-pixel LYSO:Ce Prototype NIF Gamma-Ray Imager for use in diagnosing target compression in inertial confinement fusion. This system was tested at the OMEGA Laser and exhibited significant optical, inter-pixel cross-talk that was traced to the use of a single-layer of ESR film as an inter-pixel spacer. We show how the optical cross-talk can be mapped, and discuss correction procedures. We demonstrate a 10x10 YSO:Ce array as part of an iQID (formerly BazookaSPECT) imager and discuss issues related to the internal activity of 176Lu in LSO:Ce and LYSO:Ce detectors.

  5. Imaging properties of pixellated scintillators with deep pixels.

    PubMed

    Barber, H Bradford; Fastje, David; Lemieux, Daniel; Grim, Gary P; Furenlid, Lars R; Miller, Brian W; Parkhurst, Philip; Nagarkar, Vivek V

    2014-08-17

    We have investigated the light-transport properties of scintillator arrays with long, thin pixels (deep pixels) for use in high-energy gamma-ray imaging. We compared 10×10 pixel arrays of YSO:Ce, LYSO:Ce and BGO (1mm × 1mm × 20 mm pixels) made by Proteus, Inc. with similar 10×10 arrays of LSO:Ce and BGO (1mm × 1mm × 15mm pixels) loaned to us by Saint-Gobain. The imaging and spectroscopic behaviors of these scintillator arrays are strongly affected by the choice of a reflector used as an inter-pixel spacer (3M ESR in the case of the Proteus arrays and white, diffuse-reflector for the Saint-Gobain arrays). We have constructed a 3700-pixel LYSO:Ce Prototype NIF Gamma-Ray Imager for use in diagnosing target compression in inertial confinement fusion. This system was tested at the OMEGA Laser and exhibited significant optical, inter-pixel cross-talk that was traced to the use of a single-layer of ESR film as an inter-pixel spacer. We show how the optical cross-talk can be mapped, and discuss correction procedures. We demonstrate a 10×10 YSO:Ce array as part of an iQID (formerly BazookaSPECT) imager and discuss issues related to the internal activity of (176)Lu in LSO:Ce and LYSO:Ce detectors.

  6. Pixelated gamma detector

    SciTech Connect

    Dolinsky, Sergei Ivanovich; Yanoff, Brian David; Guida, Renato; Ivan, Adrian

    2016-12-27

    A pixelated gamma detector includes a scintillator column assembly having scintillator crystals and optical transparent elements alternating along a longitudinal axis, a collimator assembly having longitudinal walls separated by collimator septum, the collimator septum spaced apart to form collimator channels, the scintillator column assembly positioned adjacent to the collimator assembly so that the respective ones of the scintillator crystal are positioned adjacent to respective ones of the collimator channels, the respective ones of the optical transparent element are positioned adjacent to respective ones of the collimator septum, and a first photosensor and a second photosensor, the first and the second photosensor each connected to an opposing end of the scintillator column assembly. A system and a method for inspecting and/or detecting defects in an interior of an object are also disclosed.

  7. Pixelation Effects in Weak Lensing

    NASA Technical Reports Server (NTRS)

    High, F. William; Rhodes, Jason; Massey, Richard; Ellis, Richard

    2007-01-01

    Weak gravitational lensing can be used to investigate both dark matter and dark energy but requires accurate measurements of the shapes of faint, distant galaxies. Such measurements are hindered by the finite resolution and pixel scale of digital cameras. We investigate the optimum choice of pixel scale for a space-based mission, using the engineering model and survey strategy of the proposed Supernova Acceleration Probe as a baseline. We do this by simulating realistic astronomical images containing a known input shear signal and then attempting to recover the signal using the Rhodes, Refregier, and Groth algorithm. We find that the quality of shear measurement is always improved by smaller pixels. However, in practice, telescopes are usually limited to a finite number of pixels and operational life span, so the total area of a survey increases with pixel size. We therefore fix the survey lifetime and the number of pixels in the focal plane while varying the pixel scale, thereby effectively varying the survey size. In a pure trade-off for image resolution versus survey area, we find that measurements of the matter power spectrum would have minimum statistical error with a pixel scale of 0.09' for a 0.14' FWHM point-spread function (PSF). The pixel scale could be increased to 0.16' if images dithered by exactly half-pixel offsets were always available. Some of our results do depend on our adopted shape measurement method and should be regarded as an upper limit: future pipelines may require smaller pixels to overcome systematic floors not yet accessible, and, in certain circumstances, measuring the shape of the PSF might be more difficult than those of galaxies. However, the relative trends in our analysis are robust, especially those of the surface density of resolved galaxies. Our approach thus provides a snapshot of potential in available technology, and a practical counterpart to analytic studies of pixelation, which necessarily assume an idealized shape

  8. A 3D Printed Toolbox for Opto-Mechanical Components

    PubMed Central

    P. Torres, Juan; Valencia, Alejandra

    2017-01-01

    In this article we present the development of a set of opto-mechanical components (a kinematic mount, a translation stage and an integrating sphere) that can be easily built using a 3D printer based on Fused Filament Fabrication (FFF) and parts that can be found in any hardware store. Here we provide a brief description of the 3D models used and some details on the fabrication process. Moreover, with the help of three simple experimental setups, we evaluate the performance of the opto-mechanical components developed by doing a quantitative comparison with its commercial counterparts. Our results indicate that the components fabricated are highly customizable, low-cost, require a short time to be fabricated and surprisingly, offer a performance that compares favorably with respect to low-end commercial alternatives. PMID:28099494

  9. Opto-mechanical subsystem with temperature compensation through isothemal design

    NASA Technical Reports Server (NTRS)

    Goodwin, F. E. (Inventor)

    1977-01-01

    An opto-mechanical subsystem for supporting a laser structure which minimizes changes in the alignment of the laser optics in response to temperature variations is described. Both optical and mechanical structural components of the system are formed of the same material, preferably beryllium, which is selected for high mechanical strength and good thermal conducting qualities. All mechanical and optical components are mounted and assembled to provide thorough thermal coupling throughout the subsystem to prevent the development of temperature gradients.

  10. Opto-Electronic Oscillator Using Suppressed Phase Modulation

    NASA Technical Reports Server (NTRS)

    Dick, G. John; Yu, Nan

    2007-01-01

    A proposed opto-electronic oscillator (OEO) would generate a microwave signal having degrees of frequency stability and spectral purity greater than those achieved in prior OEOs. The design of this system provides for reduction of noise levels (including the level of phase noise in the final output microwave signal) to below some of the fundamental limits of the prior OEOs while retaining the advantages of photonic generation of microwaves.

  11. Opto-acoustic breast imaging with co-registered ultrasound

    NASA Astrophysics Data System (ADS)

    Zalev, Jason; Clingman, Bryan; Herzog, Don; Miller, Tom; Stavros, A. Thomas; Oraevsky, Alexander; Kist, Kenneth; Dornbluth, N. Carol; Otto, Pamela

    2014-03-01

    We present results from a recent study involving the ImagioTM breast imaging system, which produces fused real-time two-dimensional color-coded opto-acoustic (OA) images that are co-registered and temporally inter- leaved with real-time gray scale ultrasound using a specialized duplex handheld probe. The use of dual optical wavelengths provides functional blood map images of breast tissue and tumors displayed with high contrast based on total hemoglobin and oxygen saturation of the blood. This provides functional diagnostic information pertaining to tumor metabolism. OA also shows morphologic information about tumor neo-vascularity that is complementary to the morphological information obtained with conventional gray scale ultrasound. This fusion technology conveniently enables real-time analysis of the functional opto-acoustic features of lesions detected by readers familiar with anatomical gray scale ultrasound. We demonstrate co-registered opto-acoustic and ultrasonic images of malignant and benign tumors from a recent clinical study that provide new insight into the function of tumors in-vivo. Results from the Feasibility Study show preliminary evidence that the technology may have the capability to improve characterization of benign and malignant breast masses over conventional diagnostic breast ultrasound alone and to improve overall accuracy of breast mass diagnosis. In particular, OA improved speci city over that of conventional diagnostic ultrasound, which could potentially reduce the number of negative biopsies performed without missing cancers.

  12. Opto-galvanic effect on degenerate magnetic states of sputtered atoms in a glow discharge

    NASA Astrophysics Data System (ADS)

    Zhechev, D.; Steflekova, V.

    2014-12-01

    The opto-galvanic response of some degenerate states of sputtered atoms to linearly- and circularly polarize light is studied. On the same optical transition both time-resolved- and amplitude opto-galvanic signals are found depending on the polarizations of light absorbed. The latter induces galvanic responses differing in opto-galvanic efficiency, time-evolution and sensitivity to discharge current and laser power. The differences are ascribed to the rate constants of the decay processes, characterizing aligned and oriented atoms.

  13. THE KEPLER PIXEL RESPONSE FUNCTION

    SciTech Connect

    Bryson, Stephen T.; Haas, Michael R.; Dotson, Jessie L.; Koch, David G.; Borucki, William J.; Tenenbaum, Peter; Jenkins, Jon M.; Chandrasekaran, Hema; Caldwell, Douglas A.; Klaus, Todd; Gilliland, Ronald L.

    2010-04-20

    Kepler seeks to detect sequences of transits of Earth-size exoplanets orbiting solar-like stars. Such transit signals are on the order of 100 ppm. The high photometric precision demanded by Kepler requires detailed knowledge of how the Kepler pixels respond to starlight during a nominal observation. This information is provided by the Kepler pixel response function (PRF), defined as the composite of Kepler's optical point-spread function, integrated spacecraft pointing jitter during a nominal cadence and other systematic effects. To provide sub-pixel resolution, the PRF is represented as a piecewise-continuous polynomial on a sub-pixel mesh. This continuous representation allows the prediction of a star's flux value on any pixel given the star's pixel position. The advantages and difficulties of this polynomial representation are discussed, including characterization of spatial variation in the PRF and the smoothing of discontinuities between sub-pixel polynomial patches. On-orbit super-resolution measurements of the PRF across the Kepler field of view are described. Two uses of the PRF are presented: the selection of pixels for each star that maximizes the photometric signal-to-noise ratio for that star, and PRF-fitted centroids which provide robust and accurate stellar positions on the CCD, primarily used for attitude and plate scale tracking. Good knowledge of the PRF has been a critical component for the successful collection of high-precision photometry by Kepler.

  14. From Pixels to Planets

    NASA Technical Reports Server (NTRS)

    Brownston, Lee; Jenkins, Jon M.

    2015-01-01

    The Kepler Mission was launched in 2009 as NASAs first mission capable of finding Earth-size planets in the habitable zone of Sun-like stars. Its telescope consists of a 1.5-m primary mirror and a 0.95-m aperture. The 42 charge-coupled devices in its focal plane are read out every half hour, compressed, and then downlinked monthly. After four years, the second of four reaction wheels failed, ending the original mission. Back on earth, the Science Operations Center developed the Science Pipeline to analyze about 200,000 target stars in Keplers field of view, looking for evidence of periodic dimming suggesting that one or more planets had crossed the face of its host star. The Pipeline comprises several steps, from pixel-level calibration, through noise and artifact removal, to detection of transit-like signals and the construction of a suite of diagnostic tests to guard against false positives. The Kepler Science Pipeline consists of a pipeline infrastructure written in the Java programming language, which marshals data input to and output from MATLAB applications that are executed as external processes. The pipeline modules, which underwent continuous development and refinement even after data started arriving, employ several analytic techniques, many developed for the Kepler Project. Because of the large number of targets, the large amount of data per target and the complexity of the pipeline algorithms, the processing demands are daunting. Some pipeline modules require days to weeks to process all of their targets, even when run on NASA's 128-node Pleiades supercomputer. The software developers are still seeking ways to increase the throughput. To date, the Kepler project has discovered more than 4000 planetary candidates, of which more than 1000 have been independently confirmed or validated to be exoplanets. Funding for this mission is provided by NASAs Science Mission Directorate.

  15. A Low-Cost Viscometer from an Opto-Mechanical Mouse

    ERIC Educational Resources Information Center

    Doroodmand, Mohammad Mahdi; Maleki, Norooz; Kazemi, Hojjatollah

    2010-01-01

    A simple, sensitive, and portable viscometer has been designed using an opto-mechanical mouse. The viscosity of a fluid is measured using the infrared light-emitting diodes and the optical diodes of an opto-mechanical mouse. These components are positioned near the top and bottom of a glass tube containing the fluid to be measured. The viscosity…

  16. Opto-ultrasound imaging in vivo in deep tissue

    NASA Astrophysics Data System (ADS)

    Si, Ke; YanXu; Zheng, Yao; Zhu, Xinpei; Gong, Wei

    2016-02-01

    It is of keen importance of deep tissue imaging with high resolution in vivo. Here we present an opto-ultrasound imaging method which utilizes an ultrasound to confine the laser pulse in a very tiny spot as a guide star. The results show that the imaging depth is 2mm with a resolution of 10um. Meanwhile, the excitation power we used is less than 2mW, which indicates that our methods can be applied in vivo without optical toxicity and optical bleaching due to the excitation power.

  17. VCSEL-based flexible opto-fluidic fluorescence sensors

    NASA Astrophysics Data System (ADS)

    Kang, Dongseok; Gai, Boju; Yoon, Jongseung

    2016-03-01

    Flexible opto-fluidic fluorescence sensors based on microscale vertical cavity surface emitting lasers (micro-VCSELs) and silicon photodiodes (Si-PDs) are demonstrated, where arrays of 850 nm micro-VCSELs and thin film Si-PDs are heterogeneously integrated on a polyethylene terephthalate (PET) substrate by transfer printing, in conjunction with elastomeric fluidic channel. Enabled with optical isolation trenches together with wavelength- and angle-selective spectral filters implemented to suppress the absorption of excitation light, the integrated flexible fluorescence sensors exhibited significantly enhanced signal-to-background ratio, resulting in a maximum sensitivity of 5 × 10-5 wt% of infrared-absorbing organic dyes.

  18. Personnel screening with terahertz opto-mechanical scanning imaging

    NASA Astrophysics Data System (ADS)

    Guo, Lan-tao; Liu, Xin; Deng, Chao; Zhao, Yuan-meng; Zhang, Cun-lin

    2014-11-01

    We presented a passive THz opto-mechnical scanning imaging method using a single detector and a trihedral scanning mirror. The system improved the imaging speed through employing two flapping mirrors. Also the trihedral scanning mirror and an ellipsoidal mirror were adopted. The parameters were set as follows: the best imaging distance was 2.2m with the image range of 1.6m (W) ×1.6m (H), the imaging time was 2s, and the resolution was 3cm. We imaged human body with different objects concealed under their clothes, such as buckle, ceramic chip, etc.

  19. Local Pixel Bundles: Bringing the Pixels to the People

    NASA Astrophysics Data System (ADS)

    Anderson, Jay

    2014-12-01

    The automated galaxy-based alignment software package developed for the Frontier Fields program (hst2galign, see Anderson & Ogaz 2014 and http://www.stsci.edu/hst/campaigns/frontier-fields/) produces a direct mapping from the pixels of the flt frame of each science exposure into a common master frame. We can use these mappings to extract the flt-pixels in the vicinity of a source of interest and package them into a convenient "bundle". In addition to the pixels, this data bundle can also contain "meta" information that will allow users to transform positions from the flt pixels to the reference frame and vice-versa. Since the un-resampled pixels in the flt frames are the only true constraints we have on the astronomical scene, the ability to inter-relate these pixels will enable many high-precision studies, such as: point-source-fitting and deconvolution with accurate PSFs, easy exploration of different image-combining algorithms, and accurate faint-source finding and photometry. The data products introduced in this ISR are a very early attempt to provide the flt-level pixel constraints in a package that is accessible to more than the handful of experts in HST astrometry. The hope is that users in the community might begin using them and will provide feedback as to what information they might want to see in the bundles and what general analysis packages they might find useful. For that reason, this document is somewhat informally written, since I know that it will be modified and updated as the products and tools are optimized.

  20. Controlling signal transport in a carbon nanotube opto-transistor

    NASA Astrophysics Data System (ADS)

    Li, Jinjin; Chu, Yanhui; Zhu, Ka-Di

    2016-11-01

    With the highly competitive development of communication technologies, modern information manufactures place high importance on the ability to control the transmitted signal using easy miniaturization materials. A controlled and miniaturized optical information device is, therefore, vital for researchers in information and communication fields. Here we propose a controlled signal transport in a doubly clamped carbon nanotube system, where the transmitted signal can be controlled by another pump beam. Pump off results in the transmitted signal off, while pump on results in the transmitted signal on. The more pump, the more amplified output signal transmission. Analogous with traditional cavity optomechanical system, the role of optical cavity is played by a localized exciton in carbon nanotube while the role of the mechanical element is played by the nanotube vibrations, which enables the realization of an opto-transistor based on carbon nanotube. Since the signal amplification and attenuation have been observed in traditional optomechanical system, and the nanotube optomechanical system has been realized in laboratory, the proposed carbon nanotube opto-transistor could be implemented in current experiments and open the door to potential applications in modern optical networks and future quantum networks.

  1. Electron optics of nanoplasmonic metamaterials in bio/opto theranostics

    NASA Astrophysics Data System (ADS)

    Roper, D. Keith; DeJarnette, Drew; Forcherio, Gregory T.; Dunklin, Jeremy; Berry, Keith; Jang, Gyoung G.; Lisunova, Milana; Blake, Phillip; Ahn, Wonmi

    2014-08-01

    Opto-electronic coupling of plasmonic nano-antennas in the near infrared water window in vitro and in vivo is of growing interest for imaging contrast agents, spectroscopic labels and rulers, biosensing, drug-delivery, and optoplasmonic ablation. Metamaterials composed of nanoplasmonic meta-atoms offer improved figures of merit in many applications across a broader spectral window. Discrete and coupled dipole approximations effectively describe localized and coupled resonance modes in nanoplasmonic metamaterials. From numeric and experimental results have emerged four design principles to guide fabrication and implementation of metamaterials in bio-related devices and systems. Resonance intensity and sensitivity are enhanced by surface-to-mass of meta-atoms and lattice constant. Fano resonant coupling is dependent on meta-atom polarizability and lattice geometry. Internal reflection in plasmonic metaatom- containing polymer films enhances dissipation rate. Dimensions of self-assembled meta-atoms depend on balancing electrochemical and surface forces. Examples of these principles from our lab compare computation with images and spectra from ordered metal-ceramic and polymeric nanocomposite metamaterials for bio/opto theranostic applications. These principles speed design and description of new architectures for nanoplasmonic metamaterials that show promise for bioapplications.

  2. Microstructured polymer optical fibre sensors for opto-acoustic endoscopy

    NASA Astrophysics Data System (ADS)

    Broadway, Christian; Gallego, Daniel; Pospori, Andreas; Zubel, Michal; Webb, David J.; Sugden, Kate; Carpintero, Guillermo; Lamela, Horacio

    2016-04-01

    Opto-acoustic imaging is a growing field of research in recent years, providing functional imaging of physiological biomarkers, such as the oxygenation of haemoglobin. Piezo electric transducers are the industry standard detector for ultrasonics, but their limited bandwidth, susceptibility to electromagnetic interference and their inversely proportional sensitivity to size all affect the detector performance. Sensors based on polymer optical fibres (POF) are immune to electromagnetic interference, have lower acoustic impedance and a reduced Young's Modulus compared to silica fibres. Furthermore, POF enables the possibility of a wideband sensor and a size appropriate to endoscopy. Micro-structured POF (mPOF) used in an interferometric detector has been shown to be an order of magnitude more sensitive than silica fibre at 1 MHz and 3 times more sensitive at 10 MHz. We present the first opto-acoustic measurements obtained using a 4.7mm PMMA mPOF Bragg grating with a fibre diameter of 130 μm and present the lateral directivity pattern of a PMMA mPOF FBG ultrasound sensor over a frequency range of 1-50 MHz. We discuss the impact of the pattern with respect to the targeted application and draw conclusions on how to mitigate the problems encountered.

  3. Nonlinear opto-isolator with response persistence function

    NASA Astrophysics Data System (ADS)

    Guo, Weilian; Zhang, Shilin; Zhang, Peining; Mao, Luhong; Zhou, Jan

    2002-09-01

    By encapsulating a light emitting diode (LED) with a Silicon photo-negative resistance Device face to face in a hermetic package, a new type opto-isolator has been developed. Because of the features of Bistability and self-latching on the silicon photo-negative resistance devices, these non-linear opto-isolators present the response persistence function for the input signal. In this paper, the demonstration of response persistance function on PDUBAT type of silicon photo-negative resistance device has been made experimentally. The Dual Base Transistor (DUBAT) is a three terminals Voltage controlled negative resistance device, it is composed from the combination of a pnp type lateral bipolar transistor and a npn type vertical bipolar transistor. As DUBAT is radiated by light, the npn bipolar transistor is taken as a phototransistor. Thus the DUBAT will become a photo-DUBAT or PDUBAT. In PDUBAT, it is found that the photo-controlled "S" negative resistance characteristic can introduce a photo-controlled current switching effect and the persistance response functions, which keeps the response state for the input light signal until the reset signal changes the circuit from maintaining state to waiting state.

  4. Controlling signal transport in a carbon nanotube opto-transistor

    PubMed Central

    Li, Jinjin; Chu, Yanhui; Zhu, Ka-Di

    2016-01-01

    With the highly competitive development of communication technologies, modern information manufactures place high importance on the ability to control the transmitted signal using easy miniaturization materials. A controlled and miniaturized optical information device is, therefore, vital for researchers in information and communication fields. Here we propose a controlled signal transport in a doubly clamped carbon nanotube system, where the transmitted signal can be controlled by another pump beam. Pump off results in the transmitted signal off, while pump on results in the transmitted signal on. The more pump, the more amplified output signal transmission. Analogous with traditional cavity optomechanical system, the role of optical cavity is played by a localized exciton in carbon nanotube while the role of the mechanical element is played by the nanotube vibrations, which enables the realization of an opto-transistor based on carbon nanotube. Since the signal amplification and attenuation have been observed in traditional optomechanical system, and the nanotube optomechanical system has been realized in laboratory, the proposed carbon nanotube opto-transistor could be implemented in current experiments and open the door to potential applications in modern optical networks and future quantum networks. PMID:27849016

  5. Rapidly and continuously frequency-scanning opto-electronic oscillator.

    PubMed

    Cen, Qizhuang; Dai, Yitang; Yin, Feifei; Zhou, Yue; Li, Jianqiang; Dai, Jian; Yu, Lan; Xu, Kun

    2017-01-23

    An opto-electronic oscillator (OEO) scheme which operates at "chirp oscillation" mode and generates low-phase-noise, frequency-swept microwave is proposed and experimentally demonstrated. This frequency-swept OEO is achieved by embedding a rapidly frequency-scanning microwave filter in an opto-electronic cavity. The filter has fixed passband while its center frequency scans rapidly and periodically at cavity round-trip time, covering a large frequency range (~GHz). Experimentally, the generated frequency-swept microwave is linear frequency-modulated continuous wave (FMCW) which centers at 7 GHz with 1-GHz bandwidth. Its instantaneous frequency varies linearly from 6.5 GHz to 7.5 GHz, back and forth, in a period of 12.8 μs, resulting in a frequency scanning rate of ~156 MHz/μs. The single-side-band (SSB) noise of the generated FMCW is -104 dBc/Hz at 10 kHz offset frequency, which is much lower than that from a commercial electronic arbitrary waveform generator (E-AWG). Improvement as large as 23 dB is experimentally reported.

  6. Nonplanar push-pull chromophores for opto-electronic applications.

    PubMed

    Breiten, Benjamin; Biaggio, Ivan; Diederich, François

    2010-01-01

    Donor-substituted cyanoethynylethenes (CEEs) are planar push-pull chromophores featuring intense intramolecular charge-transfer (CT) interactions and high third-order optical nonlinearities. Their thermal stability allows for the formation of crystalline thin films by vapor-phase deposition. On the other hand, high-quality amorphous thin films are preferred for opto-electronic applications and such films can be prepared using nonplanar push-pull chromophores with a less pronounced propensity to crystallize. By taking advantage of a versatile, atom-economic 'click-chemistry'-type transformation, involving a formal [2 + 2] cycloaddition of tetracyanoethene (TCNE) to electron-rich alkynes, followed by cycloreversion, stable donor-substituted 1,1,4,4-tetracyanobuta-1,3-dienes (TCBDs) are obtained in high yield and large quantities. These nonplanar push-pull chromophores also feature intense intramolecular CT and, in many cases, high third-order optical nonlinearities. Some of these compounds form high-optical-quality amorphous thin films by vapor-phase deposition, and first applications in next-generation opto-electronic devices have already been demonstrated. Chiral derivatives display high helical twisting power and are efficient dopants to translate molecular into macroscopic chirality, by switching nematic into cholesteric liquid crystalline phases.

  7. WFC3 Pixel Area Maps

    NASA Astrophysics Data System (ADS)

    Kalirai, J. S.; Cox, C.; Dressel, L.; Fruchter, A.; Hack, W.; Kozhurina-Platais, V.; Mack, J.

    2010-04-01

    We present the pixel area maps (PAMs) for the WFC3/UVIS and WFC3/IR detectors, and discuss the normalization of these images. HST processed flt images suffer from geometric distortion and therefore have pixel areas that vary on the sky. The counts (electrons) measured for a source on these images depends on the position of the source on the detector, an effect that is implicitly corrected when these images are multidrizzled into drz files. The flt images can be multiplied by the PAMs to yield correct and uniform counts for a given source irrespective of its location on the image. To ensure consistency between the count rate measured for sources in drz images and near the center of flt images, we set the normalization of the PAMs to unity at a reference pixel near the center of the UVIS mosaic and IR detector, and set the SCALE in the IDCTAB equal to the square root of the area of this reference pixel. The implications of this choice for photometric measurements are discussed.

  8. Ultra-realistic imaging and OptoClones

    NASA Astrophysics Data System (ADS)

    Bjelkhagen, Hans I.; Lembessis, Alkiviadis; Sarakinos, Andreas

    2016-03-01

    Recent improvements in solid state CW lasers, recording materials and light sources (such as LED lights) for displaying color holograms are described. Full-color analogue holograms can now be created with substantially better image characteristics than previously possible. To record ultra-realistic images depends on selecting the optimal recording laser wavelengths and employing ultra-fine-grain, silver-halide materials. The image quality is improved by using LED display light with improved spatial coherence. Recording museum artifacts using mobile holographic equipment is described. The most recent recorded such holograms (referred to as OptoClones™) are the Fabergé Eggs at the Fabergé Museum in St. Petersburg, Russia.

  9. Opto-Electronic Oscillator Stabilized By A Hyperfine Atomic Transition

    NASA Technical Reports Server (NTRS)

    Strekalov, Dmitry; Aveline, David; Matsko, Andrey B.; Thompson, Robert; Yu, Nan

    2004-01-01

    Opto-electronic oscillator (OEO) is a closed-loop system with part of the loop is implemented by an optical beam, and the rest by RF circuitry. The technological advantage of this approach over traditional all-RF loops in the gigahertz range comes from the that frequency filtering can be done far more efficiently in the optical range with compact, low power, and have superior stability. In this work, we report our preliminary results on using the phenomenon of coherent population trapping in (87) Rb vapor as an optical filter. Such a filter allows us to stabilize the OEO at the hyperfine splitting frequency of rubidium, thus implementing a novel type of frequency standard.

  10. CARMENES. II: optical and opto-mechanical design

    NASA Astrophysics Data System (ADS)

    Seifert, W.; Sánchez Carrasco, M. A.; Xu, W.; Cárdenas, M. C.; Sánchez-Blanco, E.; Becerril, S.; Feiz, C.; Ramón, A.; Dreizler, S.; Rohde, P.; Quirrenbach, A.; Amado, P. J.; Ribas, I.; Reiners, A.; Mandel, H.; Caballero, J. A.

    2012-09-01

    CARMENES is a fiber-fed high-resolution échelle spectrograph for the Calar Alto 3.5m telescope. The instrument is built by a German-Spanish consortium under the lead of the Landessternwarte Heidelberg. The search for planets around M dwarfs with a radial velocity accuracy of 1 m/s is the main focus of the planned science. Two channels, one for the visible, another for the near-infrared, will allow observations in the complete wavelength range from 550 to 1700 nm. To ensure the stability, the instrument is working in vacuum in a thermally controlled environment. The optical design of both channels of the instrument and the front-end, as well as the opto-mechanical design, are described.

  11. Japanese technology assessment: Computer science, opto- and microelectronics mechatronics, biotechnology

    SciTech Connect

    Brandin, D.; Wieder, H.; Spicer, W.; Nevins, J.; Oxender, D.

    1986-01-01

    The series studies Japanese research and development in four high-technology areas - computer science, opto and microelectronics, mechatronics (a term created by the Japanese to describe the union of mechanical and electronic engineering to produce the next generation of machines, robots, and the like), and biotechnology. The evaluations were conducted by panels of U.S. scientists - chosen from academia, government, and industry - actively involved in research in areas of expertise. The studies were prepared for the purpose of aiding the U.S. response to Japan's technological challenge. The main focus of the assessments is on the current status and long-term direction and emphasis of Japanese research and development. Other aspects covered include evolution of the state of the art; identification of Japanese researchers, R and D organizations, and resources; and comparative U.S. efforts. The general time frame of the studies corresponds to future industrial applications and potential commercial impacts spanning approximately the next two decades.

  12. Ultrasensitive nanomechanical mass sensor using hybrid opto-electromechanical systems.

    PubMed

    Jiang, Cheng; Cui, Yuanshun; Zhu, Ka-Di

    2014-06-02

    Nanomechanical resonators provide an unparalleled mass sensitivity sufficient to detect single biomolecules, viruses and nanoparticles. In this work we propose a scheme for mass sensing based on the hybrid opto-electromechanical system, where a mechanical resonator is coupled to an optical cavity and a microwave cavity simultaneously. When the two cavities are driven by two pump fields with proper frequencies and powers, a weak probe field is used to scan across the optical cavity resonance frequency. The mass of a single baculovirus landing onto the surface of the mechanical resonator can be measured by tracking the resonance frequency shift in the probe transmission spectrum before and after the deposition. We also propose a nonlinear mass sensor based on the measurement of the four-wave mixing (FWM) spectrum, which can be used to weigh a single 20-nm-diameter gold nanoparticle with sub-femtogram resolution.

  13. Broadband opto-mechanical phase shifter for photonic integrated circuits

    NASA Astrophysics Data System (ADS)

    Guo, Xiang; Zou, Chang-Ling; Ren, Xi-Feng; Sun, Fang-Wen; Guo, Guang-Can

    2012-08-01

    A broadband opto-mechanical phase shifter for photonic integrated circuits is proposed and numerically investigated. The structure consists of a mode-carrying waveguide and a deformable non-mode-carrying nanostring, which are parallel with each other. Since the nanostring can be deflected by the optical gradient force between the waveguide and the nanostring, the effective refractive indices of the waveguide will be changed and a phase shift will be generated. The phase shift under different geometry sizes, launched powers and boundary conditions are calculated and the dynamical properties as well as the thermal noise's effect are also discussed. It is demonstrated that a π phase shift can be realized with only about 0.64 mW launched power and 50 μm long nanostring. The proposed phase shifter may find potential usage in future investigation of photonic integrated circuits.

  14. Further applications for mosaic pixel FPA technology

    NASA Astrophysics Data System (ADS)

    Liddiard, Kevin C.

    2011-06-01

    In previous papers to this SPIE forum the development of novel technology for next generation PIR security sensors has been described. This technology combines the mosaic pixel FPA concept with low cost optics and purpose-designed readout electronics to provide a higher performance and affordable alternative to current PIR sensor technology, including an imaging capability. Progressive development has resulted in increased performance and transition from conventional microbolometer fabrication to manufacture on 8 or 12 inch CMOS/MEMS fabrication lines. A number of spin-off applications have been identified. In this paper two specific applications are highlighted: high performance imaging IRFPA design and forest fire detection. The former involves optional design for small pixel high performance imaging. The latter involves cheap expendable sensors which can detect approaching fire fronts and send alarms with positional data via mobile phone or satellite link. We also introduce to this SPIE forum the application of microbolometer IR sensor technology to IoT, the Internet of Things.

  15. Smart pixel camera based signal processing in an interferometric test station for massive parallel inspection of MEMS and MOEMS

    NASA Astrophysics Data System (ADS)

    Styk, Adam; Lambelet, Patrick; Røyset, Arne; Kujawińska, Małgorzata; Gastinger, Kay

    2010-09-01

    The paper presents the electro-optical design of an interferometric inspection system for massive parallel inspection of Micro(Opto)ElectroMechanicalSystems (M(O)EMS). The basic idea is to adapt a micro-optical probing wafer to the M(O)EMS wafer under test. The probing wafer is exchangeable and contains a micro-optical interferometer array: a low coherent interferometer (LCI) array based on a Mirau configuration and a laser interferometer (LI) array based on a Twyman-Green configuration. The interference signals are generated in the micro-optical interferometers and are applied for M(O)EMS shape and deformation measurements by means of LCI and for M(O)EMS vibration analysis (the resonance frequency and spatial mode distribution) by means of LI. Distributed array of 5×5 smart pixel imagers detects the interferometric signals. The signal processing is based on the "on pixel" processing capacity of the smart pixel camera array, which can be utilised for phase shifting, signal demodulation or envelope maximum determination. Each micro-interferometer image is detected by the 140 × 146 pixels sub-array distributed in the imaging plane. In the paper the architecture of cameras with smart-pixel approach are described and their application for massive parallel electrooptical detection and data reduction is discussed. The full data processing paths for laser interferometer and low coherent interferometer are presented.

  16. EDFA-based coupled opto-electronic oscillator and its phase noise

    NASA Technical Reports Server (NTRS)

    Salik, Ertan; Yu, Nan; Tu, Meirong; Maleki, Lute

    2004-01-01

    EDFA-based coupled opto-electronic oscillator (COEO), an integrated optical and microwave oscillator that can generate picosecond optical pulses, is presented. the phase noise measurements of COEO show better performance than synthesizer-driven mode-locked laser.

  17. Reliability study of opto-coupled semiconductor devices and Light Emitting Diodes (LED)

    NASA Technical Reports Server (NTRS)

    Maurer, R. C.; Weissflug, V. A.; Sisul, E. V.

    1977-01-01

    Opto-coupler and light emitting diode (LED) failure mechanisms and associated activation energies were determind from the results of environmental and accelerated lift tests of over 2,400 devices. The evaluation program included LED phototransistor opto-couplers from three sources, LED photoamplifier opto-couplers from a single source, and discrete infrared emitting LEDs from two sources. Environmental tests to evaluate device mechanical integrity included power cycling (10,000 cycles), temperature cycling (500 cycles) and a sequence of monitored shock, monitored vibration and constant acceleration. Multiple temperature operating life tests were conducted at ambient temperatures between 25 C and 200 C. Opto-couplers were operated in both the 'on' and 'off' states during life testing.

  18. Volumetric Spatial Correlations of Neurovascular Coupling Studied using Single Pulse Opto-fMRI.

    PubMed

    Christie, Isabel N; Wells, Jack A; Kasparov, Sergey; Gourine, Alexander V; Lythgoe, Mark F

    2017-02-08

    Neurovascular coupling describes the link between neuronal activity and cerebral blood flow. This relationship has been the subject of intense scrutiny, with most previous work seeking to understand temporal correlations that describe neurovascular coupling. However, to date, the study of spatial correlations has been limited to two-dimensional mapping of neuronal or vascular derived signals emanating from the brain's surface, using optical imaging techniques. Here, we investigate spatial correlations of neurovascular coupling in three dimensions, by applying a single 10 ms pulse of light to trigger optogenetic activation of cortical neurons transduced to express channelrhodopsin2, with concurrent fMRI. We estimated the spatial extent of increased neuronal activity using a model that takes into the account the scattering and absorption of blue light in brain tissue together with the relative density of channelrhodopsin2 expression across cortical layers. This method allows precise modulation of the volume of activated tissue in the cerebral cortex with concurrent three-dimensional mapping of functional hyperemia. Single pulse opto-fMRI minimizes adaptation, avoids heating artefacts and enables confined recruitment of the neuronal activity. Using this novel method, we present evidence for direct proportionality of volumetric spatial neurovascular coupling in the cerebral cortex.

  19. Volumetric Spatial Correlations of Neurovascular Coupling Studied using Single Pulse Opto-fMRI

    PubMed Central

    Christie, Isabel N.; Wells, Jack A.; Kasparov, Sergey; Gourine, Alexander V.; Lythgoe, Mark F.

    2017-01-01

    Neurovascular coupling describes the link between neuronal activity and cerebral blood flow. This relationship has been the subject of intense scrutiny, with most previous work seeking to understand temporal correlations that describe neurovascular coupling. However, to date, the study of spatial correlations has been limited to two-dimensional mapping of neuronal or vascular derived signals emanating from the brain’s surface, using optical imaging techniques. Here, we investigate spatial correlations of neurovascular coupling in three dimensions, by applying a single 10 ms pulse of light to trigger optogenetic activation of cortical neurons transduced to express channelrhodopsin2, with concurrent fMRI. We estimated the spatial extent of increased neuronal activity using a model that takes into the account the scattering and absorption of blue light in brain tissue together with the relative density of channelrhodopsin2 expression across cortical layers. This method allows precise modulation of the volume of activated tissue in the cerebral cortex with concurrent three-dimensional mapping of functional hyperemia. Single pulse opto-fMRI minimizes adaptation, avoids heating artefacts and enables confined recruitment of the neuronal activity. Using this novel method, we present evidence for direct proportionality of volumetric spatial neurovascular coupling in the cerebral cortex. PMID:28176823

  20. Opto-electrical energy conversion by thin electrolytic CdSe films on Ni substrates

    NASA Astrophysics Data System (ADS)

    Glenis, G. X.; Athanassopoulou, M. D.; Argyropoulos, Th G.; Dervos, C. T.

    2015-02-01

    Thin-films (300 nm) of zinc-blende (cubic structure) CdSe (111) electrolytically deposited on nickel substrates had their surface characteristics investigated by XRD, SEM, and profilometry scans. A metal-CdSe-metal structure was formed by positioning a Au electrode on top of CdSe and the I-V characteristics of the resulting device were investigated in the dark and under low intensities (≤0.2 mW cm-2) of diffused solar radiation. The experimental results show that the illuminated structure is an active device that produces electric power in the 2nd quadrant of the I-V curve. This response may be related to the Ni-to-CdSe interface, where carriers are effectively generated as a result of deep energy level formations, spatially confined in the interfacial region of the depletion layer width of the Ni-CdSe junction. A potential energy diagram is proposed to present the spatially and energetically confined deep-level parameters, the operation principles (carrier generation and transport processes) across the structure and link them to the obtained I-V response. A mathematical modeling based on the Schokley-Read-Hall recombination theory confirms the experimentally obtained current profiles of illuminated junctions. Such opto-electrical tranducers might be implemented in multilayer photovoltaic hetero-structures to enhance their conversion efficiencies and reduce their operating temperatures.

  1. Study of Opto-electronic Properties of a Single Microtubule in the Microwave Regime

    DTIC Science & Technology

    2013-01-09

    Annual Report for AOARD Grant FA2386-11-1-0001 “Research Title” Study of opto-electronic properties of a single microtubule in the microwave regime...SUBTITLE Study of opto-electronic properties of a single microtubule in the microwave regime 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...signature [porcine (brain neuron), human (MCF 7 active breast cancer cell), fungi 26 (Agaricus bisporus mashroom,) and plant (six days old soybean

  2. Packaging technology of OptoBGA for 2.4 Gb/s

    NASA Astrophysics Data System (ADS)

    Yanagisawa, Mitsuo; Wada, Hisayoshi; Matsuzono, Seigo; Sato, Shingo; Matsuda, Shin; Ooike, Satoshi; Tanahashi, Shigeo; Uegaki, Shoji

    2000-04-01

    The significantly increasing transmission capacity in the subscriber system are accelerating demands for higher data transmission speed, low cost, and system miniaturization in the millennium approaches. The key solution for the demands, smaller, lower cost, and high performance package, is surface technology. OptoBGA package has been developed to meet this challenge, a surface mountable type optical package that is designed for high frequency transmission speeds. OptoBGA package has a BGA structure to bring forth effectively size and cost reduction for the packaging. OptoBGA consists of ceramic material, a robust material, which has many advantages such as design flexibility with fine design rule, ease of process technology, high performance, and high reliability. The design of OptoBGA was made possible by improvement in the physical structure. The results of this research produced an OptoBGA with a return loss of about -20dB at 10GHz. Furthermore, reliability test evaluations have been conducted to demonstrate that the OptoBGA can withstand harsh environments.

  3. SAR Image Complex Pixel Representations

    SciTech Connect

    Doerry, Armin W.

    2015-03-01

    Complex pixel values for Synthetic Aperture Radar (SAR) images of uniform distributed clutter can be represented as either real/imaginary (also known as I/Q) values, or as Magnitude/Phase values. Generally, these component values are integers with limited number of bits. For clutter energy well below full-scale, Magnitude/Phase offers lower quantization noise than I/Q representation. Further improvement can be had with companding of the Magnitude value.

  4. Single-pixel hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Suo, Jinli; Wang, Yuwang; Bian, Liheng; Dai, Qionghai

    2016-10-01

    Conventional multispectral imaging methods detect photons of a 3D hyperspectral data cube separately either in the spatial or spectral dimension using array detectors, and are thus photon inefficient and spectrum range limited. Besides, they are usually bulky and highly expensive. To address these issues, this paper presents single-pixel multispectral imaging techniques, which are of high sensitivity, wide spectrum range, low cost and light weight. Two mechanisms are proposed, and experimental validation are also reported.

  5. CMOS digital pixel sensors: technology and applications

    NASA Astrophysics Data System (ADS)

    Skorka, Orit; Joseph, Dileepan

    2014-04-01

    CMOS active pixel sensor technology, which is widely used these days for digital imaging, is based on analog pixels. Transition to digital pixel sensors can boost signal-to-noise ratios and enhance image quality, but can increase pixel area to dimensions that are impractical for the high-volume market of consumer electronic devices. There are two main approaches to digital pixel design. The first uses digitization methods that largely rely on photodetector properties and so are unique to imaging. The second is based on adaptation of a classical analog-to-digital converter (ADC) for in-pixel data conversion. Imaging systems for medical, industrial, and security applications are emerging lower-volume markets that can benefit from these in-pixel ADCs. With these applications, larger pixels are typically acceptable, and imaging may be done in invisible spectral bands.

  6. Mapping Electrical Crosstalk in Pixelated Sensor Arrays

    NASA Technical Reports Server (NTRS)

    Seshadri, Suresh (Inventor); Cole, David (Inventor); Smith, Roger M (Inventor); Hancock, Bruce R. (Inventor)

    2013-01-01

    The effects of inter pixel capacitance in a pixilated array may be measured by first resetting all pixels in the array to a first voltage, where a first image is read out, followed by resetting only a subset of pixels in the array to a second voltage, where a second image is read out, where the difference in the first and second images provide information about the inter pixel capacitance. Other embodiments are described and claimed.

  7. Mapping Electrical Crosstalk in Pixelated Sensor Arrays

    NASA Technical Reports Server (NTRS)

    Seshadri, Suresh (Inventor); Cole, David (Inventor); Smith, Roger M. (Inventor); Hancock, Bruce R. (Inventor)

    2017-01-01

    The effects of inter pixel capacitance in a pixilated array may be measured by first resetting all pixels in the array to a first voltage, where a first image is read out, followed by resetting only a subset of pixels in the array to a second voltage, where a second image is read out, where the difference in the first and second images provide information about the inter pixel capacitance. Other embodiments are described and claimed.

  8. Oxide semiconductors for organic opto-electronic devices

    NASA Astrophysics Data System (ADS)

    Sigdel, Ajaya K.

    In this dissertation, I have introduced various concepts on the modulations of various surface, interface and bulk opto-electronic properties of ZnO based semiconductor for charge transport, charge selectivity and optimal device performance. I have categorized transparent semiconductors into two sub groups depending upon their role in a device. Electrodes, usually 200 to 500 nm thick, optimized for good transparency and transporting the charges to the external circuit. Here, the electrical conductivity in parallel direction to thin film, i.e bulk conductivity is important. And contacts, usually 5 to 50 nm thick, are optimized in case of solar cells for providing charge selectivity and asymmetry to manipulate the built in field inside the device for charge separation and collection. Whereas in Organic LEDs (OLEDs), contacts provide optimum energy level alignment at organic oxide interface for improved charge injections. For an optimal solar cell performance, transparent electrodes are designed with maximum transparency in the region of interest to maximize the light to pass through to the absorber layer for photo-generation, plus they are designed for minimum sheet resistance for efficient charge collection and transport. As such there is need for material with high conductivity and transparency. Doping ZnO with some common elements such as B, Al, Ga, In, Ge, Si, and F result in n-type doping with increase in carriers resulting in high conductivity electrode, with better or comparable opto-electronic properties compared to current industry-standard indium tin oxide (ITO). Furthermore, improvement in mobility due to improvement on crystallographic structure also provide alternative path for high conductivity ZnO TCOs. Implementing these two aspects, various studies were done on gallium doped zinc oxide (GZO) transparent electrode, a very promising indium free electrode. The dynamics of the superimposed RF and DC power sputtering was utilized to improve the

  9. Making a trillion pixels dance

    NASA Astrophysics Data System (ADS)

    Singh, Vivek; Hu, Bin; Toh, Kenny; Bollepalli, Srinivas; Wagner, Stephan; Borodovsky, Yan

    2008-03-01

    In June 2007, Intel announced a new pixelated mask technology. This technology was created to address the problem caused by the growing gap between the lithography wavelength and the feature sizes patterned with it. As this gap has increased, the quality of the image has deteriorated. About a decade ago, Optical Proximity Correction (OPC) was introduced to bridge this gap, but as this gap continued to increase, one could not rely on the same basic set of techniques to maintain image quality. The computational lithography group at Intel sought to alleviate this problem by experimenting with additional degrees of freedom within the mask. This paper describes the resulting pixelated mask technology, and some of the computational methods used to create it. The first key element of this technology is a thick mask model. We realized very early in the development that, unlike traditional OPC methods, the pixelated mask would require a very accurate thick mask model. Whereas in the traditional methods, one can use the relatively coarse approximations such as the boundary layer method, use of such techniques resulted not just in incorrect sizing of parts of the pattern, but in whole features missing. We built on top of previously published domain decomposition methods, and incorporated limitations of the mask manufacturing process, to create an accurate thick mask model. Several additional computational techniques were invoked to substantially increase the speed of this method to a point that it was feasible for full chip tapeout. A second key element of the computational scheme was the comprehension of mask manufacturability, including the vital issue of the number of colors in the mask. While it is obvious that use of three or more colors will give the best image, one has to be practical about projecting mask manufacturing capabilities for such a complex mask. To circumvent this serious issue, we eventually settled on a two color mask - comprising plain glass and etched

  10. Opto-electro-fluidics and tip coax conical surface plasmons

    NASA Astrophysics Data System (ADS)

    Miloh, Touvia

    2016-08-01

    The concept of electromagnetic energy enhancement and nanofocusing phenomena near the tip of a metaconical conducting tip by means of a surface plasmon-polaritons mechanism is discussed theoretically. In particular, we consider conical metallic structures with small apex angles and derive the corresponding dispersion relation under optimal (maximal field enhancement) operating conditions. It is demonstrated analytically that the aforementioned conditions can induce large dielectrophoretic forces near the conical tip, which can be harnessed for sorting and controlling nanoparticles in a manner similar to optical tweezers. Similarly, by considering Joule heating effects in the metal and heat conduction in the surrounding solute, it is shown that a considerable (dc) flow convection and mixing can be generated in the aqueous phase near the tip by such ac incited optical means (including common low-input lasers operating in the visible and near-infrared spectrum ranges). Analytic near-field expressions are also obtained for the opto-electro-thermo-induced flow and vorticity distributions in the electrolyte exhibiting a singular behavior near the rounded tip. Using a coax conical metastructure composed of two noble metals, surface-plasmon field enhancement is a technique for the optimal manipulation of dielectric and polarizable nanoparticles as well as for inducing indirect mixing in the liquid around the tip by generating microvortices.

  11. Organic (opto)electronic materials: understanding charge carrier dynamics

    NASA Astrophysics Data System (ADS)

    Ostroverkhova, Oksana

    2008-05-01

    There is growing interest in using organic (opto)electronic materials for applications in electronics and photonics. In particular, organic semiconductor thin films offer several advantages over traditional silicon technology, including low-cost processing, the potential for large-area flexible devices, high-efficiency light emission, and widely tunable properties through functionalization of the molecules. Over the past decade, remarkable progress in materials design and purification has been made, which led to applications of organic semiconductors in light-emitting diodes, polymer lasers, photovoltaic cells, high-speed photodetectors, organic thin-film transistors, and many others. Most of the applications envisioned for organic semiconductors rely on their conductive or photoconductive properties. However, despite remarkable progress in organic electronics and photonics, the nature of charge carrier photogeneration and transport in organic semiconductors is not completely understood and remains controversial, partly due to difficulties in assessing intrinsic properties that are often masked by impurities, grain boundaries, etc. Measurements of charge carrier dynamics at picosecond time scales after excitation reveal the intrinsic nature of mobile charge carriers before they are trapped at defect sites. In this presentation, I will review the current state of the field and summarize our recent results on photoconductivity of novel high-performance organic semiconductors (such as functionalized pentacene and anthradithiophene thin films) from picoseconds to seconds after photoexcitation. Photoluminescent properties of these novel materials will also be discussed.

  12. Microstamped opto-mechanical actuator for tactile displays

    NASA Astrophysics Data System (ADS)

    Camargo, Carlos J.; Torras, Núria; Campanella, Humberto; Marshall, Jean E.; Zinoviev, Kirill; Campo, Eva M.; Terentjev, Eugene M.; Esteve, Jaume

    2011-10-01

    Over the last few years, several technologies have been adapted for use in tactile displays, such as thermo-pneumatic actuators, piezoelectric polymers and dielectric elastomers. None of these approaches offers high-performance for refreshable Braille display system (RBDS), due to considerations of weight, power efficiency and response speed. Optical actuation offers an attractive alternative to solve limitations of current-art technologies, allowing electromechanical decoupling, elimination of actuation circuits and remote controllability. Creating these opticallydriven devices requires liquid crystal - carbon nanotube (LC-CNT) composites that show a reversible shape change in response to an applied light. This work thus reports on novel opto-actuated Braille dots based on LC-CNT composite and silicon mold microstamping. The manufacturing approach succeeds on producing blisters according to the Braille standard for the visually impaired, by taking shear-aligned LC-CNT films and silicon stamps. For this application, we need to define specifically-shaped structures. Some technologies have succeeded on elastomer microstructuring. Nevertheless, they are not applicable for LC-CNT molding because they do not consider the stretching of the polymer which is required for LC-CNT fabrication. Our process demonstrates that composites micro-molding and their 3-D structuring is feasible by silicon-based stamping. Its work principle involves the mechanical stretching, allowing the LC mesogens alignment.

  13. Controllable optical response in hybrid opto-electromechanical systems

    NASA Astrophysics Data System (ADS)

    Jiang, Cheng; Cui, Yuan-Shun; Liu, Hong-Xiang; Li, Xiao-Wei; Chen, Gui-Bin

    2015-05-01

    We theoretically investigate the analog of electromagnetically induced absorption and parametric amplification in a hybrid opto-electromechanical system consisting of an optical cavity and a microwave cavity coupled to a common mechanical resonator. When the two cavity modes are driven by two pump fields, a weak probe beam is applied to the optical cavity to monitor the optical response of the hybrid system, which can be effectively controlled by adjusting the frequency and power of the two pump fields. We find that the analog of electromagnetically induced absorption and parametric amplification can appear in the probe transmission spectrum when one cavity is pumped on its red sideband and another is pumped on its blue sideband. These phenomena can find potential applications in optical switching and signal amplification in the quantum information process. Project supported by the National Natural Science Foundation of China (Grant Nos. 11304110 and 11174101), the Natural Science Foundation of Jiangsu Province, China (Grant Nos. BK20130413 and BK2011411), the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (Grant No. 13KJB140002).

  14. MOF-based electronic and opto-electronic devices.

    PubMed

    Stavila, V; Talin, A A; Allendorf, M D

    2014-08-21

    Metal-organic frameworks (MOFs) are a class of hybrid materials with unique optical and electronic properties arising from rational self-assembly of the organic linkers and metal ions/clusters, yielding myriads of possible structural motifs. The combination of order and chemical tunability, coupled with good environmental stability of MOFs, are prompting many research groups to explore the possibility of incorporating these materials as active components in devices such as solar cells, photodetectors, radiation detectors, and chemical sensors. Although this field is only in its incipiency, many new fundamental insights relevant to integrating MOFs with such devices have already been gained. In this review, we focus our attention on the basic requirements and structural elements needed to fabricate MOF-based devices and summarize the current state of MOF research in the area of electronic, opto-electronic and sensor devices. We summarize various approaches to designing active MOFs, creation of hybrid material systems combining MOFs with other materials, and assembly and integration of MOFs with device hardware. Critical directions of future research are identified, with emphasis on achieving the desired MOF functionality in a device and establishing the structure-property relationships to identify and rationalize the factors that impact device performance.

  15. Live cell opto-injection by femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Baumgart, J.; Bintig, W.; Ngezahayo, A.; Ertmer, W.; Lubatschowski, H.; Heisterkamp, A.

    2007-02-01

    Fluorescence imaging of cells and cell organelles requires labeling by fluorophores. The labeling of living cells is often done by transfection of fluorescent proteins. Viral vectors are transferring the DNA into the cell. To avoid the use of viruses, it is possible to perforate the cell membrane for example by electro-shocks, the so called electroporation, so that the fluorescent proteins can diffuse into the cell. This method causes cell death in up to 50% of the treated cells because the damage of the outer membrane is too large. A less lethal perforation of the cell membrane with high efficiency can be realized by femtosecond (fs) laser pulses. Transient pores are created by focusing the laser beam for some milliseconds on the membrane. Through this pore, the proteins can enter into the cell. This was demonstrated in a proof of principle experiment for a few cells, but it is essential to develop an opto-perforation system for large numbers of cells in order to obtain statistically significant samples for biological experiments. The relationship between pulse energy, irradiation time, repetition rate and efficacy of the transfer of a chromophor into the cells as well as the viability of the cells was analysed. The cell viability was observed up to 90 minutes after manipulation.

  16. New Schemes for Improved Opto-Electronic Oscillator

    NASA Technical Reports Server (NTRS)

    Maleki, Lute; Yao, Steve; Ji, Yu; Ilchenko, Vladimir

    2000-01-01

    The opto-Electronic Oscillator (OEO) has already demonstrated superior spectral purity as a for microwave and millimeter wave reference signals. Experimental results have produced a performance characterized by noise as low as -50 dBc/Hz at 10 Hz and -140 dBc/Hz for a 10 GHz oscillator. This performance is significant because it was produced by an oscillator that was free running. Since the noise in an OEO is independent of the oscillation frequency, the same performance may also be obtained at higher frequency. The recent work in our laboratory has been focused in three areas: 1) realization of a compact OEO based on semiconductor lasers and modulators, 2) reduction of the close-to-carrier noise of the OEO originating from the 1/f noise of the amplifier, and 3) miniaturization of the OEO. In this paper we report on progress made in these areas, and describe future plans to increase the performance and the efficiency of the OEO.

  17. Organic non-linear optics and opto-electronics

    NASA Astrophysics Data System (ADS)

    Maldonado, J. L.; Ramos-Ortíz, G.; Rodríguez, M.; Meneses-Nava, M. A.; Barbosa-García, O.; Santillán, R.; Farfán, N.

    2010-12-01

    π-conjugated organic molecules and polymers are of great importance in physics, chemistry, material science and engineering. It is expected that, in the near future, organic materials will find widespread use in many technological applications. In the case of organic opto-electronic systems, the list of devices includes light emitting diodes (OLEDs), photovoltaic cells (OPVs), field-effect transistors (OFET), photorefractive materials for light manipulation, among others. These materials are also used for photonic applications: all-optical switching, modulators, optical correlators, plastic waveguides, all polymeric integrated circuits, solid-state lasers, and for biophotonic applications as in the case of the development of organic labels for multiphoton microscopy and photodynamic therapy. The advances in the developing of organic compounds with better mechanical, electrical, and optical (linear and non-linear) characteristics are of a great importance for this field. Here, we present the research on this area carried out at the Centro de Investigaciones en Óp-tica (CIO), in collaboration with Chemistry Departments of different institutions. This work focuses on the optical characterization of materials through several techniques such as TOF, FWM, TBC, THG Maker Fringes, HRS, Z-scan, and TPEF. Additionally, some applications, such as dynamic holography by using photorefractive polymers, and OPVs cells will be discussed.

  18. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra (Inventor); Kemeny, Sabrina E. (Inventor)

    1995-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node.

  19. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra (Inventor); Kemeny, Sabrina E. (Inventor)

    2003-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node.

  20. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra (Inventor); Kemeny, Sabrina E. (Inventor)

    2004-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node.

  1. Proceedings of PIXEL98 -- International pixel detector workshop

    SciTech Connect

    Anderson, D.F.; Kwan, S.

    1998-08-01

    Experiments around the globe face new challenges of more precision in the face of higher interaction rates, greater track densities, and higher radiation doses, as they look for rarer and rarer processes, leading many to incorporate pixelated solid-state detectors into their plans. The highest-readout rate devices require new technologies for implementation. This workshop reviewed recent, significant progress in meeting these technical challenges. Participants presented many new results; many of them from the weeks--even days--just before the workshop. Brand new at this workshop were results on cryogenic operation of radiation-damaged silicon detectors (dubbed the Lazarus effect). Other new work included a diamond sensor with 280-micron collection distance; new results on breakdown in p-type silicon detectors; testing of the latest versions of read-out chip and interconnection designs; and the radiation hardness of deep-submicron processes.

  2. Serial Pixel Analog-to-Digital Converter

    SciTech Connect

    Larson, E D

    2010-02-01

    This method reduces the data path from the counter to the pixel register of the analog-to-digital converter (ADC) from as many as 10 bits to a single bit. The reduction in data path width is accomplished by using a coded serial data stream similar to a pseudo random number (PRN) generator. The resulting encoded pixel data is then decoded into a standard hexadecimal format before storage. The high-speed serial pixel ADC concept is based on the single-slope integrating pixel ADC architecture. Previous work has described a massively parallel pixel readout of a similar architecture. The serial ADC connection is similar to the state-of-the art method with the exception that the pixel ADC register is a shift register and the data path is a single bit. A state-of-the-art individual-pixel ADC uses a single-slope charge integration converter architecture with integral registers and “one-hot” counters. This implies that parallel data bits are routed among the counter and the individual on-chip pixel ADC registers. The data path bit-width to the pixel is therefore equivalent to the pixel ADC bit resolution.

  3. Atomic Clock Based on Opto-Electronic Oscillator

    NASA Technical Reports Server (NTRS)

    Maleki, Lute; Yu, Nan

    2005-01-01

    A proposed highly accurate clock or oscillator would be based on the concept of an opto-electronic oscillator (OEO) stabilized to an atomic transition. Opto-electronic oscillators, which have been described in a number of prior NASA Tech Briefs articles, generate signals at frequencies in the gigahertz range characterized by high spectral purity but not by longterm stability or accuracy. On the other hand, the signals generated by previously developed atomic clocks are characterized by long-term stability and accuracy but not by spectral purity. The proposed atomic clock would provide high spectral purity plus long-term stability and accuracy a combination of characteristics needed to realize advanced developments in communications and navigation. In addition, it should be possible to miniaturize the proposed atomic clock. When a laser beam is modulated by a microwave signal and applied to a photodetector, the electrical output of the photodetector includes a component at the microwave frequency. In atomic clocks of a type known as Raman clocks or coherent-population-trapping (CPT) clocks, microwave outputs are obtained from laser beams modulated, in each case, to create two sidebands that differ in frequency by the amount of a hyperfine transition in the ground state of atoms of an element in vapor form in a cell. The combination of these sidebands produces a transparency in the population of a higher electronic level that can be reached from either of the two ground-state hyperfine levels by absorption of a photon. The beam is transmitted through the vapor to a photodetector. The components of light scattered or transmitted by the atoms in the two hyperfine levels mix in the photodetector and thereby give rise to a signal at the hyperfine- transition frequency. The proposed atomic clock would include an OEO and a rubidium- or cesium- vapor cell operating in the CPT/Raman regime (see figure). In the OEO portion of this atomic clock, as in a typical prior OEO, a

  4. Packaging and characterization of micro-opto-electro-mechanical systems

    NASA Astrophysics Data System (ADS)

    Saupe, Ray; Otto, Thomas; Stock, Volker; Fritzsch, Uwe; Gessner, Thomas

    2004-04-01

    Modern optical analytics require more and more compact and cost-effective modules for analysis of surfaces, solids, thin films, powders, pastes, gels, liquids and alike. Thereby a fast and non-invasive measurement is often necessary. Microsystem technology, more precisely Micro-Opto-Electro-Mechanical System (MOEMS) technology is suitable for the realization of such modules. Different miniaturized optical analyzers employing MOEMS have been developed at the Fraunhofer Institute for Reliability and Microintegration (IZM) in collaboration with the Center for Microtechnologies (ZfM) and the company COLOUR CONTROL Farbmesstechnik GmbH. These devices are based on the principle of spectral sensing in the infrared range. Due to the requirement of compact dimensions and short optical paths a high packaging accuracy is necessary. In the development process different setups with a continuous packaging improvement have been realized. The first packaging principle was based on particularly assembled laser-cut stainless steel sheets and optical standard components. The design requires exact positioning of the functional elements to attain a sufficient optical resolution. The reduction of the active components by means of monolithic combinations was one improvement. Further progress could be achieved by a package made of aluminum cast, whose models were provided using modern methods of rapid prototyping. Consequently adjustment tolerances will be minimized and the vibration stability will be increased. During the development process, simulations and characterization of the system are essential to obtain necessary improvements. Thereby an evaluation of the packaging accuracy regarding its influence on the defocus was made. According to precision and reproducibility, the optical and electrical performance are being tested.

  5. METIS opto-mechanical design and packaging study

    NASA Astrophysics Data System (ADS)

    Kroes, Gabby; ter Horst, Rik; Kragt, Jan; Roelfsema, Ronald; Navarro, Ramón; Venema, Lars; Lenzen, Rainer; Rohloff, Ralf R.; Durand, Gilles; Pantin, Eric; Ronayette, Samuel; Todd, Stephen; Bennett, Richard; Glasse, Alistair; Blommaert, Joris; Brandl, Bernhard; Teuwen, Maurice; Janssen, Huub; Huisman, Robert

    2010-07-01

    METIS: "Mid-infrared ELT Imager and Spectrograph" is the mid-infrared (3 - 14 microns) instrument for imaging and spectroscopy for the European Extremely Large Telescope (E-ELT). To ensure high detection sensitivity the internal radiation of the instrument needs to be eliminated (sufficiently reduced) and thus needs to be operated at cryogenic temperatures. The instrument is divided in a cold and warm system. The cold system, the actual heart of the system, is subdivided into five main opto-mechanical modules located within a common cryostat (part of the warm system). The warm system provides the crucial environment for the cold system, including the instrument control and maintenance equipment. The end 2009 finished Phase-A study carried out within the framework of the ESO sponsored E-ELT instrumentation studies has been performed by an international consortium with institutes from Netherlands (PI: Bernhard Brandl - NOVA), Germany, France, United Kingdom and Belgium. During this conference various aspects of the METIS instrument (design) are presented in several papers, including the instrument concept and science case, and the system engineering and optical design. This paper describes the design constraints and key issues regarding the packaging of this complex cryogenic instrument. The design solutions to create a light, small and fully accessible instrument are discussed together with the specific subdivision of the cold and warm system to ensure concurrent development at various different institutes around Europe. In addition the paper addresses the design and development studies for the special, challenging units such as the large optical image de-rotator, the (2D) chopper mechanism and the special cryogenic drives.

  6. Design and Synthesis of Microscale Opto-Magnetic Trapping Handles

    NASA Astrophysics Data System (ADS)

    Lawson, Joseph L.

    Opto-Magnetic Trapping (OMT) is a novel micromanipulation technology capable of translating particles with nanometer precision and producing forces on the order of pico-Newtons. OMT combines the benefits of optical trapping (OT) to manipulate handle particles in translational directions and magnetic trapping (MT) to provide rotational control. This combined manipulation technology shows promise for applications ranging from novel single molecule force spectroscopy to advanced manufacturing of smart micro or nano structures. Successful OMT requires handles containing material properties amenable to both OT and MT individually. Since these material properties are traditionally exclusive, novel anisotropic handles must be synthesized to accommodate both micromanipulation technologies. This body of research advances the state of the art in micromanipulation technology by addressing the fundamental material incompatibility issues associated with OMT. Novel micro-scale "patchy" handle particles were fabricated using a glancing angle deposition (GLAD) process. Due to their composite design combining dielectric and ferromagnetic materials, these particles successfully demonstrated OMT manipulation. These particles, along with the developed GLAD fabrication process, improve upon the current state of the art by enabling the robust synthesis of a wider range of particle sizes. Furthermore, the magnetic moments of these particles can be more accurately controlled over a wider range including producing magnetic moments grater than is capable with current techniques. A thorough numerical simulation was also conducted to identify the variation of OT performance of these patchy particles with respect to standard dielectric-only OT handles. While variations in trapping location do exist, they were found to be within an acceptable range for OMT applications and are still capable of manipulation with nanometer precision.

  7. Results from SIM's Thermo-Opto-Mechanical (TOM3) Testbed

    NASA Technical Reports Server (NTRS)

    Goullioud, Renaud; Lindensmith, C. A.; Hahn, I.

    2006-01-01

    Future space-based optical interferometers, such as the Space Interferometer Mission Planet Quest (SIM), require thermal stability of the optical wavefront to the level of picometers in order to produce astrometric data at the micro-arc-second level. In SIM, the internal path of the interferometer will be measured with a small metrology beam whereas the starlight fringe position is estimated from a large concentric annular beam. To achieve the micro-arc-second observation goal for SIM, it is necessary to maintain the optical path difference between the central and the outer annulus portions of the wavefront of the front-end telescope optics to a few tens of picometers. The Thermo-Opto-Mecha nical testbed (TOM3) was developed at the Jet Propulsion Laboratory to measure thermally induced optical deformations of a full-size flight-like beam compressor and siderostat, the two largest optics on SIM, in flight-like thermal environments. A Common Path Heterodyne Interferometer (COPHI) developed at JPL was used for the fine optical path difference measurement as the metrology sensor. The system was integrated inside a large vacuum chamber in order to mitigate the atmospheric and thermal disturbances. The siderostat was installed in a temperature-controlled thermal shroud inside the vacuum chamber, creating a flight-like thermal environment. Detailed thermal and structural models of the test articles (siderostat and compressor) were also developed for model prediction and correlation of the thermal deformations. Experimental data shows SIM required thermal stability of the test articles and good agreement with the model predictions.

  8. Infrared astronomy - Pixels to spare

    SciTech Connect

    Mccaughrean, M. )

    1991-07-01

    An infrared CCD camera containing an array with 311,040 pixels arranged in 486 rows of 640 each is tested. The array is a chip of platinum silicide (PtSi), sensitive to photons with wavelengths between 1 and 6 microns. Observations of the Hubble Space Telescope, Mars, Pluto and moon are reported. It is noted that the satellite's twin solar-cell arrays, at an apparent separation of about 1 1/4 arc second, are well resolved. Some two dozen video frames were stacked to make each presented image of Mars at 1.6 microns; at this wavelength Mars appears much as it does in visible light. A stack of 11 images at a wavelength of 1.6 microns is used for an image of Jupiter with its Great Red Spot and moons Io and Europa.

  9. Dead pixel replacement in LWIR microgrid polarimeters.

    PubMed

    Ratliff, Bradley M; Tyo, J Scott; Boger, James K; Black, Wiley T; Bowers, David L; Fetrow, Matthew P

    2007-06-11

    LWIR imaging arrays are often affected by nonresponsive pixels, or "dead pixels." These dead pixels can severely degrade the quality of imagery and often have to be replaced before subsequent image processing and display of the imagery data. For LWIR arrays that are integrated with arrays of micropolarizers, the problem of dead pixels is amplified. Conventional dead pixel replacement (DPR) strategies cannot be employed since neighboring pixels are of different polarizations. In this paper we present two DPR schemes. The first is a modified nearest-neighbor replacement method. The second is a method based on redundancy in the polarization measurements.We find that the redundancy-based DPR scheme provides an order-of-magnitude better performance for typical LWIR polarimetric data.

  10. Equivalence of a Bit Pixel Image to a Quantum Pixel Image

    NASA Astrophysics Data System (ADS)

    Ortega, Laurel Carlos; Dong, Shi-Hai; Cruz-Irisson, M.

    2015-11-01

    We propose a new method to transform a pixel image to the corresponding quantum-pixel using a qubit per pixel to represent each pixels classical weight in a quantum image matrix weight. All qubits are linear superposition, changing the coefficients level by level to the entire longitude of the gray scale with respect to the base states of the qubit. Classically, these states are just bytes represented in a binary matrix, having code combinations of 1 or 0 at all pixel locations. This method introduces a qubit-pixel image representation of images captured by classical optoelectronic methods. Supported partially by the project 20150964-SIP-IPN, Mexico

  11. Method for fabricating pixelated silicon device cells

    SciTech Connect

    Nielson, Gregory N.; Okandan, Murat; Cruz-Campa, Jose Luis; Nelson, Jeffrey S.; Anderson, Benjamin John

    2015-08-18

    A method, apparatus and system for flexible, ultra-thin, and high efficiency pixelated silicon or other semiconductor photovoltaic solar cell array fabrication is disclosed. A structure and method of creation for a pixelated silicon or other semiconductor photovoltaic solar cell array with interconnects is described using a manufacturing method that is simplified compared to previous versions of pixelated silicon photovoltaic cells that require more microfabrication steps.

  12. Design of efficient and simple interface testing equipment for opto-electric tracking system

    NASA Astrophysics Data System (ADS)

    Liu, Qiong; Deng, Chao; Tian, Jing; Mao, Yao

    2016-10-01

    Interface testing for opto-electric tracking system is one important work to assure system running performance, aiming to verify the design result of every electronic interface matching the communication protocols or not, by different levels. Opto-electric tracking system nowadays is more complicated, composed of many functional units. Usually, interface testing is executed between units manufactured completely, highly depending on unit design and manufacture progress as well as relative people. As a result, it always takes days or weeks, inefficiently. To solve the problem, this paper promotes an efficient and simple interface testing equipment for opto-electric tracking system, consisting of optional interface circuit card, processor and test program. The hardware cards provide matched hardware interface(s), easily offered from hardware engineer. Automatic code generation technique is imported, providing adaption to new communication protocols. Automatic acquiring items, automatic constructing code architecture and automatic encoding are used to form a new program quickly with adaption. After simple steps, a standard customized new interface testing equipment with matching test program and interface(s) is ready for a waiting-test system in minutes. The efficient and simple interface testing equipment for opto-electric tracking system has worked for many opto-electric tracking system to test entire or part interfaces, reducing test time from days to hours, greatly improving test efficiency, with high software quality and stability, without manual coding. Used as a common tool, the efficient and simple interface testing equipment for opto-electric tracking system promoted by this paper has changed traditional interface testing method and created much higher efficiency.

  13. Commissioning of the CMS Forward Pixel Detector

    SciTech Connect

    Kumar, Ashish; /SUNY, Buffalo

    2008-12-01

    The Compact Muon Solenoid (CMS) experiment is scheduled for physics data taking in summer 2009 after the commissioning of high energy proton-proton collisions at Large Hadron Collider (LHC). At the core of the CMS all-silicon tracker is the silicon pixel detector, comprising three barrel layers and two pixel disks in the forward and backward regions, accounting for a total of 66 million channels. The pixel detector will provide high-resolution, 3D tracking points, essential for pattern recognition and precise vertexing, while being embedded in a hostile radiation environment. The end disks of the pixel detector, known as the Forward Pixel detector, has been assembled and tested at Fermilab, USA. It has 18 million pixel cells with dimension 100 x 150 {micro}m{sup 2}. The complete forward pixel detector was shipped to CERN in December 2007, where it underwent extensive system tests for commissioning prior to the installation. The pixel system was put in its final place inside the CMS following the installation and bake out of the LHC beam pipe in July 2008. It has been integrated with other sub-detectors in the readout since September 2008 and participated in the cosmic data taking. This report covers the strategy and results from commissioning of CMS forward pixel detector at CERN.

  14. Implementation of TDI based digital pixel ROIC with 15μm pixel pitch

    NASA Astrophysics Data System (ADS)

    Ceylan, Omer; Shafique, Atia; Burak, A.; Caliskan, Can; Abbasi, Shahbaz; Yazici, Melik; Gurbuz, Yasar

    2016-05-01

    A 15um pixel pitch digital pixel for LWIR time delay integration (TDI) applications is implemented which occupies one fourth of pixel area compared to previous digital TDI implementation. TDI is implemented on 8 pixels with oversampling rate of 2. ROIC provides 16 bits output with 8 bits of MSB and 8 bits of LSB. Pixel can store 75 M electrons with a quantization noise of 500 electrons. Digital pixel TDI implementation is advantageous over analog counterparts considering power consumption, chip area and signal-to-noise ratio. Digital pixel TDI ROIC is fabricated with 0.18um CMOS process. In digital pixel TDI implementation photocurrent is integrated on a capacitor in pixel and converted to digital data in pixel. This digital data triggers the summation counters which implements TDI addition. After all pixels in a row contribute, the summed data is divided to the number of TDI pixels(N) to have the actual output which is square root of N improved version of a single pixel output in terms of signal-to-noise-ratio (SNR).

  15. High stroke pixel for a deformable mirror

    DOEpatents

    Miles, Robin R.; Papavasiliou, Alexandros P.

    2005-09-20

    A mirror pixel that can be fabricated using standard MEMS methods for a deformable mirror. The pixel is electrostatically actuated and is capable of the high deflections needed for spaced-based mirror applications. In one embodiment, the mirror comprises three layers, a top or mirror layer, a middle layer which consists of flexures, and a comb drive layer, with the flexures of the middle layer attached to the mirror layer and to the comb drive layer. The comb drives are attached to a frame via spring flexures. A number of these mirror pixels can be used to construct a large mirror assembly. The actuator for the mirror pixel may be configured as a crenellated beam with one end fixedly secured, or configured as a scissor jack. The mirror pixels may be used in various applications requiring high stroke adaptive optics.

  16. Sub-pixel mapping of water boundaries using pixel swapping algorithm (case study: Tagliamento River, Italy)

    NASA Astrophysics Data System (ADS)

    Niroumand-Jadidi, Milad; Vitti, Alfonso

    2015-10-01

    Taking the advantages of remotely sensed data for mapping and monitoring of water boundaries is of particular importance in many different management and conservation activities. Imagery data are classified using automatic techniques to produce maps entering the water bodies' analysis chain in several and different points. Very commonly, medium or coarse spatial resolution imagery is used in studies of large water bodies. Data of this kind is affected by the presence of mixed pixels leading to very outstanding problems, in particular when dealing with boundary pixels. A considerable amount of uncertainty inescapably occurs when conventional hard classifiers (e.g., maximum likelihood) are applied on mixed pixels. In this study, Linear Spectral Mixture Model (LSMM) is used to estimate the proportion of water in boundary pixels. Firstly by applying an unsupervised clustering, the water body is identified approximately and a buffer area considered ensuring the selection of entire boundary pixels. Then LSMM is applied on this buffer region to estimate the fractional maps. However, resultant output of LSMM does not provide a sub-pixel map corresponding to water abundances. To tackle with this problem, Pixel Swapping (PS) algorithm is used to allocate sub-pixels within mixed pixels in such a way to maximize the spatial proximity of sub-pixels and pixels in the neighborhood. The water area of two segments of Tagliamento River (Italy) are mapped in sub-pixel resolution (10m) using a 30m Landsat image. To evaluate the proficiency of the proposed approach for sub-pixel boundary mapping, the image is also classified using a conventional hard classifier. A high resolution image of the same area is also classified and used as a reference for accuracy assessment. According to the results, sub-pixel map shows in average about 8 percent higher overall accuracy than hard classification and fits very well in the boundaries with the reference map.

  17. It's not the pixel count, you fool

    NASA Astrophysics Data System (ADS)

    Kriss, Michael A.

    2012-01-01

    The first thing a "marketing guy" asks the digital camera engineer is "how many pixels does it have, for we need as many mega pixels as possible since the other guys are killing us with their "umpteen" mega pixel pocket sized digital cameras. And so it goes until the pixels get smaller and smaller in order to inflate the pixel count in the never-ending pixel-wars. These small pixels just are not very good. The truth of the matter is that the most important feature of digital cameras in the last five years is the automatic motion control to stabilize the image on the sensor along with some very sophisticated image processing. All the rest has been hype and some "cool" design. What is the future for digital imaging and what will drive growth of camera sales (not counting the cell phone cameras which totally dominate the market in terms of camera sales) and more importantly after sales profits? Well sit in on the Dark Side of Color and find out what is being done to increase the after sales profits and don't be surprised if has been done long ago in some basement lab of a photographic company and of course, before its time.

  18. LISe pixel detector for neutron imaging

    NASA Astrophysics Data System (ADS)

    Herrera, Elan; Hamm, Daniel; Wiggins, Brenden; Milburn, Rob; Burger, Arnold; Bilheux, Hassina; Santodonato, Louis; Chvala, Ondrej; Stowe, Ashley; Lukosi, Eric

    2016-10-01

    Semiconducting lithium indium diselenide, 6LiInSe2 or LISe, has promising characteristics for neutron detection applications. The 95% isotopic enrichment of 6Li results in a highly efficient thermal neutron-sensitive material. In this study, we report on a proof-of-principle investigation of a semiconducting LISe pixel detector to demonstrate its potential as an efficient neutron imager. The LISe pixel detector had a 4×4 of pixels with a 550 μm pitch on a 5×5×0.56 mm3 LISe substrate. An experimentally verified spatial resolution of 300 μm was observed utilizing a super-sampling technique.

  19. Per-Pixel Lighting Data Analysis

    SciTech Connect

    Inanici, Mehlika

    2005-08-01

    This report presents a framework for per-pixel analysis of the qualitative and quantitative aspects of luminous environments. Recognizing the need for better lighting analysis capabilities and appreciating the new measurement abilities developed within the LBNL Lighting Measurement and Simulation Toolbox, ''Per-pixel Lighting Data Analysis'' project demonstrates several techniques for analyzing luminance distribution patterns, luminance ratios, adaptation luminance and glare assessment. The techniques are the syntheses of the current practices in lighting design and the unique practices that can be done with per-pixel data availability. Demonstrated analysis techniques are applicable to both computer-generated and digitally captured images (physically-based renderings and High Dynamic Range photographs).

  20. Anode readout for pixellated CZT detectors

    NASA Astrophysics Data System (ADS)

    Narita, Tomohiko; Grindlay, Jonathan E.; Hong, Jaesub; Niestemski, Francis C.

    2004-02-01

    Determination of the photon interaction depth offers numerous advantages for an astronomical hard X-ray telescope. The interaction depth is typically derived from two signals: anode and cathode, or collecting and non-collecting electrodes. We present some preliminary results from our depth sensing detectors using only the anode pixel signals. By examining several anode pixel signals simultaneously, we find that we can estimate the interaction depth, and get sub-pixel 2-D position resolution. We discuss our findings and the requirements for future ASIC development.

  1. ATLAS Phase-II-Upgrade Pixel data transmission development

    NASA Astrophysics Data System (ADS)

    Wensing, M.

    2017-01-01

    The ATLAS tracking system will be replaced by an all-silicon detector in the course of the planned upgrade of the Large Hadron Collider around 2025. The readout of the new pixel system will be most challenging in terms of data rate and readout speed. Simulations of the on-detector electronics based on the currently foreseen trigger rate of 1 MHz indicate that a readout speed of up to 5 Gbit/s per data link is necessary. Due to radiation levels, the first part of transmission has to be implemented electrically. System simulation and test results of cable candidates will be presented.

  2. The phase II ATLAS Pixel upgrade: the Inner Tracker (ITk)

    NASA Astrophysics Data System (ADS)

    Flick, T.

    2017-01-01

    The entire tracking system of the ATLAS experiment will be replaced during the LHC Phase II shutdown (foreseen to take place around 2025) by an all-silicon detector called the ITk (Inner Tracker). The pixel detector will comprise the five innermost layers, and will be instrumented with new sensor and readout electronics technologies to improve the tracking performance and cope with the HL-LHC environment, which will be severe in terms of occupancy and radiation. Several layout options are being investigated. All of these include a barrel part and ring-shaped supports in the endcap regions. All structures will be based on low mass, highly stable and highly thermally conductive carbon-based materials cooled by evaporative carbon dioxide. Different designs of planar, 3D, and CMOS sensors are being investigated to identify the optimal technology for the different pixel layers. While the RD53 Collaboration is developing the new readout chip, the pixel off-detector readout electronics will be implemented in the framework of the general ATLAS trigger and DAQ system. A readout speed of up to 5 Gbit/s per data link (FE-chip) will be needed in the innermost layers going down to 640 Mbit/s for the outermost. This paper presents an overview of the different components of the ITk and the current status of the developments.

  3. Pixels, Imagers and Related Fabrication Methods

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata (Inventor); Cunningham, Thomas J. (Inventor)

    2014-01-01

    Pixels, imagers and related fabrication methods are described. The described methods result in cross-talk reduction in imagers and related devices by generating depletion regions. The devices can also be used with electronic circuits for imaging applications.

  4. Pixels, Imagers and Related Fabrication Methods

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata (Inventor); Cunningham, Thomas J. (Inventor)

    2016-01-01

    Pixels, imagers and related fabrication methods are described. The described methods result in cross-talk reduction in imagers and related devices by generating depletion regions. The devices can also be used with electronic circuits for imaging applications.

  5. Toward Multispectral Imaging with Colloidal Metasurface Pixels.

    PubMed

    Stewart, Jon W; Akselrod, Gleb M; Smith, David R; Mikkelsen, Maiken H

    2017-02-01

    Multispectral colloidal metasurfaces are fabricated that exhibit greater than 85% absorption and ≈100 nm linewidths by patterning film-coupled nanocubes in pixels using a fusion of bottom-up and top-down fabrication techniques over wafer-scale areas. With this technique, the authors realize a multispectral pixel array consisting of six resonances between 580 and 1125 nm and reconstruct an RGB image with 9261 color combinations.

  6. Design of the small pixel pitch ROIC

    NASA Astrophysics Data System (ADS)

    Liang, Qinghua; Jiang, Dazhao; Chen, Honglei; Zhai, Yongcheng; Gao, Lei; Ding, Ruijun

    2014-11-01

    Since the technology trend of the third generation IRFPA towards resolution enhancing has steadily progressed,the pixel pitch of IRFPA has been greatly reduced.A 640×512 readout integrated circuit(ROIC) of IRFPA with 15μm pixel pitch is presented in this paper.The 15μm pixel pitch ROIC design will face many challenges.As we all known,the integrating capacitor is a key performance parameter when considering pixel area,charge capacity and dynamic range,so we adopt the effective method of 2 by 2 pixels sharing an integrating capacitor to solve this problem.The input unit cell architecture will contain two paralleled sample and hold parts,which not only allow the FPA to be operated in full frame snapshot mode but also save relatively unit circuit area.Different applications need more matching input unit circuits. Because the dimension of 2×2 pixels is 30μm×30μm, an input stage based on direct injection (DI) which has medium injection ratio and small layout area is proved to be suitable for middle wave (MW) while BDI with three-transistor cascode amplifier for long wave(LW). By adopting the 0.35μm 2P4M mixed signal process, the circuit architecture can make the effective charge capacity of 7.8Me- per pixel with 2.2V output range for MW and 7.3 Me- per pixel with 2.6V output range for LW. According to the simulation results, this circuit works well under 5V power supply and achieves less than 0.1% nonlinearity.

  7. Readout and DAQ for Pixel Detectors

    NASA Astrophysics Data System (ADS)

    Platkevic, Michal

    2010-01-01

    Data readout and acquisition control of pixel detectors demand the transfer of significantly a large amounts of bits between the detector and the computer. For this purpose dedicated interfaces are used which are designed with focus on features like speed, small dimensions or flexibility of use such as digital signal processors, field-programmable gate arrays (FPGA) and USB communication ports. This work summarizes the readout and DAQ system built for state-of-the-art pixel detectors of the Medipix family.

  8. Holographic imaging with single pixel sensor

    NASA Astrophysics Data System (ADS)

    Leportier, Thibault; Lee, Young Tack; Hwang, Do Kyung; Park, Min-Chul

    2016-09-01

    Imaging techniques based on CCD sensors presenting very high number of pixels enable to record images with high resolution. However, the huge storage load and high bandwidth required to store and transmit digital holographic information are technical bottlenecks that should be overcome for the future of holographic display. Techniques to capture images with single pixel sensors have been greatly improved recently with the development of compressive sensing algorithm (CS). Since interference patterns may be considered sparse, the number of measurements required to recover the information with CS is lower than the number of pixels of the reconstructed image. In addition, this method does not need any scanning system. One other advantage of single pixel imaging is that the cost of recording system can be dramatically reduced since high-resolution cameras are expensive while compressive sensing exploits only one pixel. In this paper, we present an imaging system based on phase-shifting holography. First, simulations were performed to confirm that hologram could be reconstructed by compressive sensing even if the number of measurements was smaller than the number of pixels. Then, experimental set-up was realized. Several holograms with different phase shifts introduced by quarter and half wave plates in the reference beam were acquired. We demonstrated that our system enables the reconstruction of the object.

  9. Simulation study of pixel detector charge digitization

    NASA Astrophysics Data System (ADS)

    Wang, Fuyue; Nachman, Benjamin; Sciveres, Maurice; Lawrence Berkeley National Laboratory Team

    2017-01-01

    Reconstruction of tracks from nearly overlapping particles, called Tracking in Dense Environments (TIDE), is an increasingly important component of many physics analyses at the Large Hadron Collider as signatures involving highly boosted jets are investigated. TIDE makes use of the charge distribution inside a pixel cluster to resolve tracks that share one of more of their pixel detector hits. In practice, the pixel charge is discretized using the Time-over-Threshold (ToT) technique. More charge information is better for discrimination, but more challenging for designing and operating the detector. A model of the silicon pixels has been developed in order to study the impact of the precision of the digitized charge distribution on distinguishing multi-particle clusters. The output of the GEANT4-based simulation is used to train neutral networks that predict the multiplicity and location of particles depositing energy inside one cluster of pixels. By studying the multi-particle cluster identification efficiency and position resolution, we quantify the trade-off between the number of ToT bits and low-level tracking inputs. As both ATLAS and CMS are designing upgraded detectors, this work provides guidance for the pixel module designs to meet TIDE needs. Work funded by the China Scholarship Council and the Office of High Energy Physics of the U.S. Department of Energy under contract DE-AC02-05CH11231.

  10. Steganography based on pixel intensity value decomposition

    NASA Astrophysics Data System (ADS)

    Abdulla, Alan Anwar; Sellahewa, Harin; Jassim, Sabah A.

    2014-05-01

    This paper focuses on steganography based on pixel intensity value decomposition. A number of existing schemes such as binary, Fibonacci, Prime, Natural, Lucas, and Catalan-Fibonacci (CF) are evaluated in terms of payload capacity and stego quality. A new technique based on a specific representation is proposed to decompose pixel intensity values into 16 (virtual) bit-planes suitable for embedding purposes. The proposed decomposition has a desirable property whereby the sum of all bit-planes does not exceed the maximum pixel intensity value, i.e. 255. Experimental results demonstrate that the proposed technique offers an effective compromise between payload capacity and stego quality of existing embedding techniques based on pixel intensity value decomposition. Its capacity is equal to that of binary and Lucas, while it offers a higher capacity than Fibonacci, Prime, Natural, and CF when the secret bits are embedded in 1st Least Significant Bit (LSB). When the secret bits are embedded in higher bit-planes, i.e., 2nd LSB to 8th Most Significant Bit (MSB), the proposed scheme has more capacity than Natural numbers based embedding. However, from the 6th bit-plane onwards, the proposed scheme offers better stego quality. In general, the proposed decomposition scheme has less effect in terms of quality on pixel value when compared to most existing pixel intensity value decomposition techniques when embedding messages in higher bit-planes.

  11. Focal plane array with modular pixel array components for scalability

    SciTech Connect

    Kay, Randolph R; Campbell, David V; Shinde, Subhash L; Rienstra, Jeffrey L; Serkland, Darwin K; Holmes, Michael L

    2014-12-09

    A modular, scalable focal plane array is provided as an array of integrated circuit dice, wherein each die includes a given amount of modular pixel array circuitry. The array of dice effectively multiplies the amount of modular pixel array circuitry to produce a larger pixel array without increasing die size. Desired pixel pitch across the enlarged pixel array is preserved by forming die stacks with each pixel array circuitry die stacked on a separate die that contains the corresponding signal processing circuitry. Techniques for die stack interconnections and die stack placement are implemented to ensure that the desired pixel pitch is preserved across the enlarged pixel array.

  12. Spatial clustering of pixels of a multispectral image

    DOEpatents

    Conger, James Lynn

    2014-08-19

    A method and system for clustering the pixels of a multispectral image is provided. A clustering system computes a maximum spectral similarity score for each pixel that indicates the similarity between that pixel and the most similar neighboring. To determine the maximum similarity score for a pixel, the clustering system generates a similarity score between that pixel and each of its neighboring pixels and then selects the similarity score that represents the highest similarity as the maximum similarity score. The clustering system may apply a filtering criterion based on the maximum similarity score so that pixels with similarity scores below a minimum threshold are not clustered. The clustering system changes the current pixel values of the pixels in a cluster based on an averaging of the original pixel values of the pixels in the cluster.

  13. Genetic Algorithm for Opto-thermal Skin Hydration Depth Profiling Measurements

    NASA Astrophysics Data System (ADS)

    Cui, Y.; Xiao, Perry; Imhof, R. E.

    2013-09-01

    Stratum corneum is the outermost skin layer, and the water content in stratum corneum plays a key role in skin cosmetic properties as well as skin barrier functions. However, to measure the water content, especially the water concentration depth profile, within stratum corneum is very difficult. Opto-thermal emission radiometry, or OTTER, is a promising technique that can be used for such measurements. In this paper, a study on stratum corneum hydration depth profiling by using a genetic algorithm (GA) is presented. The pros and cons of a GA compared against other inverse algorithms such as neural networks, maximum entropy, conjugate gradient, and singular value decomposition will be discussed first. Then, it will be shown how to use existing knowledge to optimize a GA for analyzing the opto-thermal signals. Finally, these latest GA results on hydration depth profiling of stratum corneum under different conditions, as well as on the penetration profiles of externally applied solvents, will be shown.

  14. Tunable multi-wavelength fiber lasers based on an Opto-VLSI processor and optical amplifiers.

    PubMed

    Xiao, Feng; Alameh, Kamal; Lee, Yong Tak

    2009-12-07

    A multi-wavelength tunable fiber laser based on the use of an Opto-VLSI processor in conjunction with different optical amplifiers is proposed and experimentally demonstrated. The Opto-VLSI processor can simultaneously select any part of the gain spectrum from each optical amplifier into its associated fiber ring, leading to a multiport tunable fiber laser source. We experimentally demonstrate a 3-port tunable fiber laser source, where each output wavelength of each port can independently be tuned within the C-band with a wavelength step of about 0.05 nm. Experimental results demonstrate a laser linewidth as narrow as 0.05 nm and an optical side-mode-suppression-ratio (SMSR) of about 35 dB. The demonstrated three fiber lasers have excellent stability at room temperature and output power uniformity less than 0.5 dB over the whole C-band.

  15. Stereo-microvision. Development of an opto-electronic operating microscope.

    PubMed

    Reinhardt, H F; Horstmann, G A; Spink, R; Amrein, E I; Forrer, P

    1993-06-01

    A novel opto-electronic operating microscope has been designed and clinically tested. It consists of a small camera microscope, a central electronic unit, and a stereoscopic video monitor. Advanced miniaturization permitted ergonomics superior to those of conventional optomechanical microscopes. Electronic imaging facilitates coupling to an ultrasound navigation system which enables the neurosurgeon to verify the location of the focus in real time, correlated with CT and MRI pictures. A fully computerized, digital operating microscope will now be developed based on this prototype.

  16. Intracavity OptoGalvanic Spectroscopy not suitable for ambient level radiocarbon detection.

    PubMed

    Paul, Dipayan; Meijer, Harro A J

    2015-09-01

    IntraCavity OptoGalvanic Spectroscopy as a radiocarbon detection technique was first reported by the Murnick group at Rutgers University, Newark, NJ, in 2008. This technique for radiocarbon detection was presented with tremendous potentials for applications in various fields of research. Significantly cheaper, this technique was portrayed as a possible complementary technique to the more expensive and complex accelerator mass spectrometry. Several groups around the world started developing this technique for various radiocarbon related applications. The IntraCavity OptoGalvanic Spectroscopy setup at the University of Groningen was constructed in 2012 in close collaboration with the Murnick group for exploring possible applications in the fields of radiocarbon dating and atmospheric monitoring. In this paper we describe a systematic evaluation of the IntraCavity OptoGalvanic Spectroscopy setup at Groningen for radiocarbon detection. Since the IntraCavity OptoGalvanic Spectroscopy setup was strictly planned for dating and atmospheric monitoring purposes, all the initial experiments were performed with CO2 samples containing contemporary levels and highly depleted levels of radiocarbon. Because of recurring failures in differentiating the two CO2 samples, with the radiocarbon concentration 3 orders of magnitude apart, CO2 samples containing elevated levels of radiocarbon were prepared in-house and experimented with. All results obtained thus far at Groningen are in sharp contrast to the results published by the Murnick group and rather support the results put forward by the Salehpour group at Uppsala University. From our extensive test work, we must conclude that the method is unsuited for ambient level radiocarbon measurements, and even highly enriched CO2 samples yield insignificant signal.

  17. Opto-injection into single living cells by femtosecond near-infrared laser

    NASA Astrophysics Data System (ADS)

    Peng, Cheng

    This dissertation presents a novel technique to deliver membrane impermeable molecules into single living cells with the assistance of femtosecond (fs) near-infrared (NIR) laser pulses. This approach merges ultrafast laser technology with key biological, biomedical, and medical applications, such as gene transfection, gene therapy and drug delivery. This technique promises several major advantages, namely, very high transfection efficiency, high cell survival rate (≈100%) and fully preserved cell viabilities. It is also a promising method to deliver molecules into cells that are difficult or even completely resistant to established physical methods, such as microinjection by glass pipettes, electroporation, and biolistics. In this work, the system for fs NIR opto-injection was designed and built. Successful fs NIR opto-injection has been performed on several cell systems including single mammalian cells (bovine aortic endothelial cells), marine animal eggs (Spisula solidissima oocytes), and human cancer cells (fibrosarcoma HT1080) cultured in a tissue-like environment. The connections between laser parameters and cell responses were explored through further experiments and in-depth analyses, especially the relationship between dye uptake rate and incident laser intensity, and the relationship between pore size created on cell membranes and incident laser intensity. Dye uptake rate of the target cells was observed to depend on incident laser intensity. Pore size was found dependent on incident laser intensity. The conclusion was made that laser-induced breakdown and plasma-induced ablation in cell membrane are the physical principles that govern the process of fs NIR opto-injection.

  18. 3D optical simulation formalism OPTOS for textured silicon solar cells.

    PubMed

    Tucher, Nico; Eisenlohr, Johannes; Kiefel, Peter; Höhn, Oliver; Hauser, Hubert; Peters, Marius; Müller, Claas; Goldschmidt, Jan Christoph; Bläsi, Benedikt

    2015-11-30

    In this paper we introduce the three-dimensional formulation of the OPTOS formalism, a matrix-based method that allows for the efficient simulation of non-coherent light propagation and absorption in thick textured sheets. As application examples, we calculate the absorptance of solar cells featuring textures on front and rear side with different feature sizes operating in different optical regimes. A discretization of polar and azimuth angle enables a three-dimensional description of systems with arbitrary surface textures. We present redistribution matrices for 3D surface textures, including pyramidal textures, binary crossed gratings and a Lambertian scatterer. The results of the OPTOS simulations for silicon sheets with different combinations of these surfaces are in accordance with both optical measurements and results based on established simulation methods like ray tracing. Using OPTOS, we show that the integration of a diffractive grating at the rear side of a silicon solar cell featuring a pyramidal front side results in absorption close to the Yablonovitch Limit enhancing the photocurrent density by 0.6 mA/cm2 for a 200 µm thick cell.

  19. Optical simulation of photovoltaic modules with multiple textured interfaces using the matrix-based formalism OPTOS.

    PubMed

    Tucher, Nico; Eisenlohr, Johannes; Gebrewold, Habtamu; Kiefel, Peter; Höhn, Oliver; Hauser, Hubert; Goldschmidt, Jan Christoph; Bläsi, Benedikt

    2016-07-11

    The OPTOS formalism is a matrix-based approach to determine the optical properties of textured optical sheets. It is extended within this work to enable the modelling of systems with an arbitrary number of textured, plane-parallel interfaces. A matrix-based system description is derived that accounts for the optical reflection and transmission interaction between all textured interfaces. Using OPTOS, we calculate reflectance and absorptance of complete photovoltaic module stacks, which consist of encapsulated silicon solar cells featuring textures that operate in different optical regimes. As exemplary systems, solar cells with and without module encapsulation are shown to exhibit a considerable absorptance gain if the random pyramid front side texture is combined with a diffractive rear side grating. A variation of the sunlight's angle of incidence reveals that the grating gain is almost not affected for incoming polar angles up to 60°. Considering as well the good agreement with alternative simulation techniques, OPTOS is demonstrated to be a versatile and efficient method for the optical analysis of photovoltaic modules.

  20. Opto-Acoustic Data Fusion for Supporting the Guidance of Remotely Operated Underwater Vehicles (ROVs)

    NASA Astrophysics Data System (ADS)

    Bruno, F.; Lagudi, A.; Ritacco, G.; Muzzupappa, M.; Guida, R.

    2015-04-01

    Remotely Operated underwater Vehicles (ROVs) play an important role in a number of operations conducted in shallow and deep water (e.g.: exploration, survey, intervention, etc.), in several application fields like marine science, offshore construction, and underwater archeology. ROVs are usually equipped with different imaging devices, both optical and acoustic. Optical sensors are able to generate better images in close range and clear water conditions, while acoustic systems are usually employed in long range acquisitions and do not suffer from the presence of turbidity, a well-known cause of coarser resolution and harder data extraction. In this work we describe the preliminary steps in the development of an opto-acoustic camera able to provide an on-line 3D reconstruction of the acquired scene. Taking full advantage of the benefits arising from the opto-acoustic data fusion techniques, the system was conceived as a support tool for ROV operators during the navigation in turbid waters, or in operations conducted by means of mechanical manipulators. The paper presents an overview of the device, an ad-hoc methodology for the extrinsic calibration of the system and a custom software developed to control the opto-acoustic camera and supply the operator with visual information.

  1. An estimation error bound for pixelated sensing

    NASA Astrophysics Data System (ADS)

    Kreucher, Chris; Bell, Kristine

    2016-05-01

    This paper considers the ubiquitous problem of estimating the state (e.g., position) of an object based on a series of noisy measurements. The standard approach is to formulate this problem as one of measuring the state (or a function of the state) corrupted by additive Gaussian noise. This model assumes both (i) the sensor provides a measurement of the true target (or, alternatively, a separate signal processing step has eliminated false alarms), and (ii) The error source in the measurement is accurately described by a Gaussian model. In reality, however, sensor measurement are often formed on a grid of pixels - e.g., Ground Moving Target Indication (GMTI) measurements are formed for a discrete set of (angle, range, velocity) voxels, and EO imagery is made on (x, y) grids. When a target is present in a pixel, therefore, uncertainty is not Gaussian (instead it is a boxcar function) and unbiased estimation is not generally possible as the location of the target within the pixel defines the bias of the estimator. It turns out that this small modification to the measurement model makes traditional bounding approaches not applicable. This paper discusses pixelated sensing in more detail and derives the minimum mean squared error (MMSE) bound for estimation in the pixelated scenario. We then use this error calculation to investigate the utility of using non-thresholded measurements.

  2. Mapping Electrical Crosstalk in Pixelated Sensor Arrays

    NASA Technical Reports Server (NTRS)

    Seshadri, S.; Cole, D. M.; Hancock, B. R.; Smith, R. M.

    2008-01-01

    Electronic coupling effects such as Inter-Pixel Capacitance (IPC) affect the quantitative interpretation of image data from CMOS, hybrid visible and infrared imagers alike. Existing methods of characterizing IPC do not provide a map of the spatial variation of IPC over all pixels. We demonstrate a deterministic method that provides a direct quantitative map of the crosstalk across an imager. The approach requires only the ability to reset single pixels to an arbitrary voltage, different from the rest of the imager. No illumination source is required. Mapping IPC independently for each pixel is also made practical by the greater S/N ratio achievable for an electrical stimulus than for an optical stimulus, which is subject to both Poisson statistics and diffusion effects of photo-generated charge. The data we present illustrates a more complex picture of IPC in Teledyne HgCdTe and HyViSi focal plane arrays than is presently understood, including the presence of a newly discovered, long range IPC in the HyViSi FPA that extends tens of pixels in distance, likely stemming from extended field effects in the fully depleted substrate. The sensitivity of the measurement approach has been shown to be good enough to distinguish spatial structure in IPC of the order of 0.1%.

  3. Pixels, Blocks of Pixels, and Polygons: Choosing a Spatial Unit for Thematic Accuracy Assessment

    EPA Science Inventory

    Pixels, polygons, and blocks of pixels are all potentially viable spatial assessment units for conducting an accuracy assessment. We develop a statistical population-based framework to examine how the spatial unit chosen affects the outcome of an accuracy assessment. The populati...

  4. Radiation tolerance of CMOS monolithic active pixel sensors with self-biased pixels

    NASA Astrophysics Data System (ADS)

    Deveaux, M.; Amar-Youcef, S.; Besson, A.; Claus, G.; Colledani, C.; Dorokhov, M.; Dritsa, C.; Dulinski, W.; Fröhlich, I.; Goffe, M.; Grandjean, D.; Heini, S.; Himmi, A.; Hu, C.; Jaaskelainen, K.; Müntz, C.; Shabetai, A.; Stroth, J.; Szelezniak, M.; Valin, I.; Winter, M.

    2010-12-01

    CMOS monolithic active pixel sensors (MAPS) are proposed as a technology for various vertex detectors in nuclear and particle physics. We discuss the mechanisms of ionizing radiation damage on MAPS hosting the dead time free, so-called self bias pixel. Moreover, we introduce radiation hardened sensor designs which allow operating detectors after exposing them to irradiation doses above 1 Mrad.

  5. A PCIe DAQ board prototype for Pixel Detector in high energy physics

    NASA Astrophysics Data System (ADS)

    Lama, L.; Balbi, G.; Falchieri, D.; Pellegrini, G.; Preti, C.; Gabrielli, A.

    2017-01-01

    We present the design of the Pixel-ROD board, which is a PCIe data acquisition circuit designed to push data coming from custom links (like GBT) into the host computer memory. The board is designed in order to be flexible and highly-configurable, making it usable with different front end electronics devices via optical or electrical connections. The PCIe interface provides a high-bandwidth link towards the memory of a PC.

  6. Active Pixel Sensors: Are CCD's Dinosaurs?

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R.

    1993-01-01

    Charge-coupled devices (CCD's) are presently the technology of choice for most imaging applications. In the 23 years since their invention in 1970, they have evolved to a sophisticated level of performance. However, as with all technologies, we can be certain that they will be supplanted someday. In this paper, the Active Pixel Sensor (APS) technology is explored as a possible successor to the CCD. An active pixel is defined as a detector array technology that has at least one active transistor within the pixel unit cell. The APS eliminates the need for nearly perfect charge transfer -- the Achilles' heel of CCDs. This perfect charge transfer makes CCD's radiation 'soft,' difficult to use under low light conditions, difficult to manufacture in large array sizes, difficult to integrate with on-chip electronics, difficult to use at low temperatures, difficult to use at high frame rates, and difficult to manufacture in non-silicon materials that extend wavelength response.

  7. Towards spark-proof gaseous pixel detectors

    NASA Astrophysics Data System (ADS)

    Tsigaridas, S.; Beuzekom, M. v.; Chan, H. W.; Graaf, H. v. d.; Hartjes, F.; Heijhoff, K.; Hessey, N. P.; Prodanovic, V.

    2016-11-01

    The micro-pattern gaseous pixel detector, is a promising technology for imaging and particle tracking applications. It is a combination of a gas layer acting as detection medium and a CMOS pixelated readout-chip. As a prevention against discharges we deposit a protection layer on the chip and then integrate on top a micromegas-like amplification structure. With this technology we are able to reconstruct 3D track segments of particles passing through the gas thanks to the functionality of the chip. We have turned a Timepix3 chip into a gaseous pixel detector and tested it at the SPS at Cern. The preliminary results are promising and within the expectations. However, the spark protection layer needs further improvement to make reliable detectors. For this reason, we have created a setup for spark-testing. We present the first results obtained from the lab-measurements along with preliminary results from the testbeam.

  8. Pixel lensing observations towards globular clusters

    NASA Astrophysics Data System (ADS)

    Cardone, V. F.; Cantiello, M.

    2003-07-01

    It has been suggested that a monitoring program employing the pixel lensing method to search for microlensing events towards galactic globular clusters may increase the statistics and discriminate among different halo models. Stimulated by this proposal, we evaluate an upper limit to the pixel lensing event rate for such a survey. Four different dark halo models have been considered changing both the flattening and the slope of the mass density profile. The lens mass function has been modelled as a homogenous power - law for mu in (mul, muu) and both the mass limits and the slope of the mass function have been varied to investigate their effect on the rate. The target globular clusters have been selected in order to minimize the disk contribution to the event rate. We find that a pixel lensing survey towards globular clusters is unable to discriminate among different halo models since the number of detectable events is too small to allow any reliable statistical analysis.

  9. Illuminant spectrum estimation at a pixel.

    PubMed

    Ratnasingam, Sivalogeswaran; Hernández-Andrés, Javier

    2011-04-01

    In this paper, an algorithm is proposed to estimate the spectral power distribution of a light source at a pixel. The first step of the algorithm is forming a two-dimensional illuminant invariant chromaticity space. In estimating the illuminant spectrum, generalized inverse estimation and Wiener estimation methods were applied. The chromaticity space was divided into small grids and a weight matrix was used to estimate the illuminant spectrum illuminating the pixels that fall within a grid. The algorithm was tested using a different number of sensor responses to determine the optimum number of sensors for accurate colorimetric and spectral reproduction. To investigate the performance of the algorithm realistically, the responses were multiplied with Gaussian noise and then quantized to 10 bits. The algorithm was tested with standard and measured data. Based on the results presented, the algorithm can be used with six sensors to obtain a colorimetrically good estimate of the illuminant spectrum at a pixel.

  10. Vivid, full-color aluminum plasmonic pixels

    PubMed Central

    Olson, Jana; Manjavacas, Alejandro; Liu, Lifei; Chang, Wei-Shun; Foerster, Benjamin; King, Nicholas S.; Knight, Mark W.; Nordlander, Peter; Halas, Naomi J.; Link, Stephan

    2014-01-01

    Aluminum is abundant, low in cost, compatible with complementary metal-oxide semiconductor manufacturing methods, and capable of supporting tunable plasmon resonance structures that span the entire visible spectrum. However, the use of Al for color displays has been limited by its intrinsically broad spectral features. Here we show that vivid, highly polarized, and broadly tunable color pixels can be produced from periodic patterns of oriented Al nanorods. Whereas the nanorod longitudinal plasmon resonance is largely responsible for pixel color, far-field diffractive coupling is used to narrow the plasmon linewidth, enabling monochromatic coloration and significantly enhancing the far-field scattering intensity of the individual nanorod elements. The bright coloration can be observed with p-polarized white light excitation, consistent with the use of this approach in display devices. The resulting color pixels are constructed with a simple design, are compatible with scalable fabrication methods, and provide contrast ratios exceeding 100:1. PMID:25225385

  11. Modulation transfer function of a trapezoidal pixel array detector

    NASA Astrophysics Data System (ADS)

    Wang, Fan; Guo, Rongli; Ni, Jinping; Dong, Tao

    2016-01-01

    The modulation transfer function (MTF) is the tool most commonly used for quantifying the performance of an electro-optical imaging system. Recently, trapezoid-shaped pixels were designed and used in a retina-like sensor in place of rectangular-shaped pixels. The MTF of a detector with a trapezoidal pixel array is determined according to its definition. Additionally, the MTFs of detectors with differently shaped pixels, but the same pixel areas, are compared. The results show that the MTF values of the trapezoidal pixel array detector are obviously larger than those of rectangular and triangular pixel array detectors at the same frequencies.

  12. Large monolithic particle pixel-detector in high-voltage CMOS technology

    NASA Astrophysics Data System (ADS)

    Perić, I.; Takacs, C.

    2010-12-01

    A large monolithic particle pixel-detector implemented as system on a chip in a high-voltage 0.35 μm CMOS technology will be presented. The detector uses high-voltage n-well/p-substrate diodes as pixel-sensors. The diodes can be reversely biased with more than 60 V. In this way, depleted zones of about 10 μm thickness are formed, where the signal charges can be collected by drift. Due to fast charge collection in the strong electric-field zones, a higher radiation tolerance of the sensor is expected than in the case of the standard MAPS detectors. Simple pixel-readout electronics are implemented inside the n-wells. The readout is based on a source follower with one select- and two reset-transistors. Due to embedding of the pixel-readout electronics inside the collecting electrodes (n-wells) there are no insensitive zones within the pixel matrix. The detector chip contains a 128×128 matrix consisting of pixels of 21×21 μm2 -size. The diode voltages of one selected pixel-row are received at the bottom of the matrix by 128 eight-bit single-slope ADCs. All ADCs operate in parallel. The ADC codes are read out using eight LVDS 500 MBit/s output links. The readout electronics are designed to allow the readout of the whole pixel matrix in less than 50 μs. The total DC power consumption of the chip is 50 mW. All analog parts of the chip are implemented using radiation-hard layout techniques. Experimental results will be presented.

  13. Commissioning of the ATLAS pixel detector

    SciTech Connect

    ATLAS Collaboration; Golling, Tobias

    2008-09-01

    The ATLAS pixel detector is a high precision silicon tracking device located closest to the LHC interaction point. It belongs to the first generation of its kind in a hadron collider experiment. It will provide crucial pattern recognition information and will largely determine the ability of ATLAS to precisely track particle trajectories and find secondary vertices. It was the last detector to be installed in ATLAS in June 2007, has been fully connected and tested in-situ during spring and summer 2008, and is ready for the imminent LHC turn-on. The highlights of the past and future commissioning activities of the ATLAS pixel system are presented.

  14. Physics performance of the ATLAS pixel detector

    NASA Astrophysics Data System (ADS)

    Tsuno, S.

    2017-01-01

    In preparation for LHC Run-2 the ATLAS detector introduced a new pixel detector, the Insertable B-Layer (IBL). This detector is located between the beampipe and what was the innermost pixel layer. The tracking and vertex reconstruction are significantly improved and good performance is expected in high level objects such a b-quark jet tagging. This in turn, leads to better physics results. This note summarizes the impact of the IBL detector on physics results, especially focusing on the analyses using b-quark jets throughout 2016 summer physics program.

  15. Dynamic holography using pixelated light modulators.

    PubMed

    Zwick, Susanne; Haist, Tobias; Warber, Michael; Osten, Wolfgang

    2010-09-01

    Dynamic holography using spatial light modulators is a very flexible technique that offers various new applications compared to static holography. We give an overview on the technical background of dynamic holography focusing on pixelated spatial light modulators and their technical restrictions, and we present a selection of the numerous applications of dynamic holography.

  16. Pixel telescope test in STAR at RHIC

    NASA Astrophysics Data System (ADS)

    Sun, Xiangming; Szelezniak, Michal; Greiner, Leo; Matis, Howard; Vu, Chinh; Stezelberger, Thorsten; Wieman, Howard

    2007-10-01

    The STAR experiment at RHIC is designing a new inner vertex detector called the Heavy Flavor Tracker (HFT). The HFT's innermost two layers is called the PIXEL detector which uses Monolithic Active Pixel Sensor technology (MAPS). To test the MAPS technology, we just constructed and tested a telescope. The telescope uses a stack of three MIMOSTAR2 chips, Each MIMOSTAR2 sensor, which was designed by IPHC, is an array of 132x128 pixels with a square pixel size of 30 μ. The readout of the telescope makes use of the ALICE DDL/SIU cards, which is compatible with the future STAR data acquisition system called DAQ1000. The telescope was first studied in a 1.2 GeV/c electron beam at LBNL's Advanced Light Source. Afterwards, the telescope was outside the STAR magnet, and then later inside it, 145 cm away from STAR's center. We will describe this first test of MAPS technology in a collider environment, and report on the occupancy, particle flux, and performance of the telescope.

  17. Amplifier based broadband pixel for sub-millimeter wave imaging

    NASA Astrophysics Data System (ADS)

    Sarkozy, Stephen; Drewes, Jonathan; Leong, Kevin M. K. H.; Lai, Richard; Mei, X. B. (Gerry); Yoshida, Wayne; Lange, Michael D.; Lee, Jane; Deal, William R.

    2012-09-01

    Broadband sub-millimeter wave technology has received significant attention for potential applications in security, medical, and military imaging. Despite theoretical advantages of reduced size, weight, and power compared to current millimeter wave systems, sub-millimeter wave systems have been hampered by a fundamental lack of amplification with sufficient gain and noise figure properties. We report a broadband pixel operating from 300 to 340 GHz, biased off a single 2 V power supply. Over this frequency range, the amplifiers provide > 40 dB gain and <8 dB noise figure, representing the current state-of-art performance capabilities. This pixel is enabled by revolutionary enhancements to indium phosphide (InP) high electron mobility transistor technology, based on a sub-50 nm gate and indium arsenide composite channel with a projected maximum oscillation frequency fmax>1.0 THz. The first sub-millimeter wave-based images using active amplification are demonstrated as part of the Joint Improvised Explosive Device Defeat Organization Longe Range Personnel Imager Program. This development and demonstration may bring to life future sub-millimeter-wave and THz applications such as solutions to brownout problems, ultra-high bandwidth satellite communication cross-links, and future planetary exploration missions.

  18. Adaptive bad pixel correction algorithm for IRFPA based on PCNN

    NASA Astrophysics Data System (ADS)

    Leng, Hanbing; Zhou, Zuofeng; Cao, Jianzhong; Yi, Bo; Yan, Aqi; Zhang, Jian

    2013-10-01

    Bad pixels and response non-uniformity are the primary obstacles when IRFPA is used in different thermal imaging systems. The bad pixels of IRFPA include fixed bad pixels and random bad pixels. The former is caused by material or manufacture defect and their positions are always fixed, the latter is caused by temperature drift and their positions are always changing. Traditional radiometric calibration-based bad pixel detection and compensation algorithm is only valid to the fixed bad pixels. Scene-based bad pixel correction algorithm is the effective way to eliminate these two kinds of bad pixels. Currently, the most used scene-based bad pixel correction algorithm is based on adaptive median filter (AMF). In this algorithm, bad pixels are regarded as image noise and then be replaced by filtered value. However, missed correction and false correction often happens when AMF is used to handle complex infrared scenes. To solve this problem, a new adaptive bad pixel correction algorithm based on pulse coupled neural networks (PCNN) is proposed. Potential bad pixels are detected by PCNN in the first step, then image sequences are used periodically to confirm the real bad pixels and exclude the false one, finally bad pixels are replaced by the filtered result. With the real infrared images obtained from a camera, the experiment results show the effectiveness of the proposed algorithm.

  19. Design Methodology: ASICs with complex in-pixel processing for Pixel Detectors

    SciTech Connect

    Fahim, Farah

    2014-10-31

    The development of Application Specific Integrated Circuits (ASIC) for pixel detectors with complex in-pixel processing using Computer Aided Design (CAD) tools that are, themselves, mainly developed for the design of conventional digital circuits requires a specialized approach. Mixed signal pixels often require parasitically aware detailed analog front-ends and extremely compact digital back-ends with more than 1000 transistors in small areas below 100μm x 100μm. These pixels are tiled to create large arrays, which have the same clock distribution and data readout speed constraints as in, for example, micro-processors. The methodology uses a modified mixed-mode on-top digital implementation flow to not only harness the tool efficiency for timing and floor-planning but also to maintain designer control over compact parasitically aware layout.

  20. WFC3/IR Cycle 19 Bad Pixel Table Update

    NASA Astrophysics Data System (ADS)

    Hilbert, B.

    2012-06-01

    Using data from Cycles 17, 18, and 19, we have updated the IR channel bad pixel table for WFC3. The bad pixel table contains flags that mark the position of pixels that are dead, unstable, have a bad zeroth read value, or are affected by "blobs". In all, 28,500 of the science pixels (2.77%) are flagged as bad. Observers are encouraged to dither their observations as a means of lessening the effects of these bad pixels. The new bad pixel table is in the calibration database system (CDBS) as w681807ii_bpx.fits.

  1. FROM THE CURRENT LITERATURE: Laser excitation of surface acoustic waves: a new direction in opto-acoustic spectroscopy of a solid

    NASA Astrophysics Data System (ADS)

    Karabutov, Aleksander A.

    1985-11-01

    Studies in thermo-optic excitation of surface acoustic waves are reviewed. The excitation of periodic and pulse signals is discussed, using nonmoving and moving beams. Most attention is paid to application of this effect for purposes of opto-acoustic spectroscopy of a solid. The possibilities and promises of using opto-acoustic spectroscopy (OAS) employing surface acoustic waves (SAW) are analyzed

  2. Design methodology: edgeless 3D ASICs with complex in-pixel processing for pixel detectors

    SciTech Connect

    Fahim Farah, Fahim Farah; Deptuch, Grzegorz W.; Hoff, James R.; Mohseni, Hooman

    2015-08-28

    The design methodology for the development of 3D integrated edgeless pixel detectors with in-pixel processing using Electronic Design Automation (EDA) tools is presented. A large area 3 tier 3D detector with one sensor layer and two ASIC layers containing one analog and one digital tier, is built for x-ray photon time of arrival measurement and imaging. A full custom analog pixel is 65μm x 65μm. It is connected to a sensor pixel of the same size on one side, and on the other side it has approximately 40 connections to the digital pixel. A 32 x 32 edgeless array without any peripheral functional blocks constitutes a sub-chip. The sub-chip is an indivisible unit, which is further arranged in a 6 x 6 array to create the entire 1.248cm x 1.248cm ASIC. Each chip has 720 bump-bond I/O connections, on the back of the digital tier to the ceramic PCB. All the analog tier power and biasing is conveyed through the digital tier from the PCB. The assembly has no peripheral functional blocks, and hence the active area extends to the edge of the detector. This was achieved by using a few flavors of almost identical analog pixels (minimal variation in layout) to allow for peripheral biasing blocks to be placed within pixels. The 1024 pixels within a digital sub-chip array have a variety of full custom, semi-custom and automated timing driven functional blocks placed together. The methodology uses a modified mixed-mode on-top digital implementation flow to not only harness the tool efficiency for timing and floor-planning but also to maintain designer control over compact parasitically aware layout. The methodology uses the Cadence design platform, however it is not limited to this tool.

  3. Hardware solutions for the 65k pixel X-ray camera module of 75 μm pixel size

    NASA Astrophysics Data System (ADS)

    Kasinski, K.; Maj, P.; Grybos, P.; Koziol, A.

    2016-02-01

    We present three hardware solutions designed for a detector module built with a 2 cm × 2 cm hybrid pixel detector built from a single 320 or 450 μ m thick silicon sensor designed and fabricated by Hamamatsu and two UFXC32k readout integrated circuits (128 × 256 pixels with 75μ m pitch, designed in CMOS 130 nm at AGH-UST). The chips work in a single photon counting mode and provide ultra-fast X-ray imaging. The presented hardware modules are designed according to requirements of various tests and applications: ṡDevice A: a fast and flexible system for tests with various radiation sources. ṡDevice B: a standalone, all-in-one imaging device providing three standard interfaces (USB 2.0, Ethernet, Camera Link) and up to 640 MB/s bandwidth. ṡDevice C: a prototype large-area imaging system. The paper shows the readout system structure for each case with highlighted circuit board designs with details on power distribution and cooling on both FR4 and LTCC (low temperature co-fired ceramic) based circuits.

  4. The opto-mechanical design for GMOX: a next-generation instrument concept for Gemini

    NASA Astrophysics Data System (ADS)

    Smee, Stephen A.; Barkhouser, Robert; Robberto, Massimo; Ninkov, Zoran; Gennaro, Mario; Heckman, Timothy M.

    2016-08-01

    We present the opto-mechanical design of GMOX, the Gemini Multi-Object eXtra-wide-band spectrograph, a potential next-generation (Gen-4 #3) facility-class instrument for Gemini. GMOX is a wide-band, multi-object, spectrograph with spectral coverage spanning 350 nm to 2.4 um with a nominal resolving power of R 5000. Through the use of Digital Micromirror Device (DMD) technology, GMOX will be able to acquire spectra from hundreds of sources simultaneously, offering unparalleled flexibility in target selection. Utilizing this technology, GMOX can rapidly adapt individual slits to either seeing-limited or diffraction-limited conditions. The optical design splits the bandpass into three arms, blue, red, and near infrared, with the near-infrared arm being split into three channels covering the Y+J band, H band, and K band. A slit viewing camera in each arm provides imaging capability for target acquisition and fast-feedback for adaptive optics control with either ALTAIR (Gemini North) or GeMS (Gemini South). Mounted at the Cassegrain focus, GMOX is a large (1.3 m x 2.8 m x 2.0 m) complex instrument, with six dichroics, three DMDs (one per arm), five science cameras, and three acquisition cameras. Roughly half of these optics, including one DMD, operate at cryogenic temperature. To maximize stiffness and simplify assembly and alignment, the opto-mechanics are divided into three main sub-assemblies, including a near-infrared cryostat, each having sub-benches to facilitate ease of alignment and testing of the optics. In this paper we present the conceptual opto-mechanical design of GMOX, with an emphasis on the mounting strategy for the optics and the thermal design details related to the near-infrared cryostat.

  5. Shaping volumetric light distribution through turbid media using real-time three-dimensional opto-acoustic feedback.

    PubMed

    Deán-Ben, X Luís; Estrada, Héctor; Razansky, Daniel

    2015-02-15

    Focusing light through turbid media represents a highly fascinating challenge in modern biophotonics. The unique capability of opto-acoustics for high-resolution imaging of light absorption contrast in deep tissues can provide a natural and efficient feedback to control light delivery in a scattering medium. While the basic feasibility of using opto-acoustic readings as a feedback mechanism for wavefront shaping has been recently reported, the suggested approaches may require long acquisition times, making them challenging to be translated into realistic tissue environments. In an attempt to significantly accelerate dynamic wavefront shaping capabilities, we present here a feedback-based approach using real-time three-dimensional opto-acoustic imaging assisted with genetic-algorithm-based optimization. The new technique offers robust performance in the presence of noisy measurements and can simultaneously control the scattered wave field in an entire volumetric region.

  6. Pixel-by-pixel absolute phase retrieval using three phase-shifted fringe patterns without markers

    NASA Astrophysics Data System (ADS)

    Jiang, Chufan; Li, Beiwen; Zhang, Song

    2017-04-01

    This paper presents a method that can recover absolute phase pixel by pixel without embedding markers on three phase-shifted fringe patterns, acquiring additional images, or introducing additional hardware component(s). The proposed three-dimensional (3D) absolute shape measurement technique includes the following major steps: (1) segment the measured object into different regions using rough priori knowledge of surface geometry; (2) artificially create phase maps at different z planes using geometric constraints of structured light system; (3) unwrap the phase pixel by pixel for each region by properly referring to the artificially created phase map; and (4) merge unwrapped phases from all regions into a complete absolute phase map for 3D reconstruction. We demonstrate that conventional three-step phase-shifted fringe patterns can be used to create absolute phase map pixel by pixel even for large depth range objects. We have successfully implemented our proposed computational framework to achieve absolute 3D shape measurement at 40 Hz.

  7. ACS/WFC Pixel Stability - Bringing the Pixels Back to the Science

    NASA Astrophysics Data System (ADS)

    Borncamp, David; Grogin, Norman A.; Bourque, Matthew; Ogaz, Sara

    2016-06-01

    Electrical current that has been trapped within the lattice structure of a Charged Coupled Device (CCD) can be present through multiple exposures, which will have an adverse effect on its science performance. The traditional way to correct for this extra charge is to take an image with the camera shutter closed periodically throughout the lifetime of the instrument. These images, generally referred to as dark images, allow for the characterization of the extra charge that is trapped within the CCD at the time of observation. This extra current can then be subtracted out of science images to correct for the extra charge that was there at this time. Pixels that have a charge above a certain threshold of current are marked as “hot” and flagged in the data quality array. However, these pixels may not be "bad" in the traditional sense that they cannot be reliably dark-subtracted. If these pixels are shown to be stable over an anneal period, the charge can be properly subtracted and the extra noise from this dark current can be taken into account. We present the results of a pixel history study that analyzes every pixel of ACS/WFC individually and allows pixels that were marked as bad to be brought back into the science image.

  8. Operational parameters of an opto-electronic neural network employing fixed planar holographic interconnects

    SciTech Connect

    Keller, P.E.; Gmitro, A.F.

    1993-07-01

    A prototype neutral network system of multifaceted, planar interconnection holograms and opto-electronic neurons is analyzed. This analysis shows that a hologram fabricated with electron-beam lithography has the capacity to connect 6700 neuron outputs to 6700 neuron inputs and that the encoded synaptic weights have a precision of approximately 5 bits. Higher interconnection densities can be achieved by accepting a lower synaptic weight accuracy. For systems employing laser diodes at the outputs of the neurons, processing rates in the range of 45 to 720 trillion connections per second can potentially be achieve.

  9. Recent Developments of an Opto-Electronic THz Spectrometer for High-Resolution Spectroscopy

    PubMed Central

    Hindle, Francis; Yang, Chun; Mouret, Gael; Cuisset, Arnaud; Bocquet, Robin; Lampin, Jean-François; Blary, Karine; Peytavit, Emilien; Akalin, Tahsin; Ducournau, Guillaume

    2009-01-01

    A review is provided of sources and detectors that can be employed in the THz range before the description of an opto-electronic source of monochromatic THz radiation. The realized spectrometer has been applied to gas phase spectroscopy. Air-broadening coefficients of HCN are determined and the insensitivity of this technique to aerosols is demonstrated by the analysis of cigarette smoke. A multiple pass sample cell has been used to obtain a sensitivity improvement allowing transitions of the volatile organic compounds to be observed. A solution to the frequency metrology is presented and promises to yield accurate molecular line center measurements. PMID:22291552

  10. Opto-fluidics based microscopy and flow cytometry on a cell phone for blood analysis.

    PubMed

    Zhu, Hongying; Ozcan, Aydogan

    2015-01-01

    Blood analysis is one of the most important clinical tests for medical diagnosis. Flow cytometry and optical microscopy are widely used techniques to perform blood analysis and therefore cost-effective translation of these technologies to resource limited settings is critical for various global health as well as telemedicine applications. In this chapter, we review our recent progress on the integration of imaging flow cytometry and fluorescent microscopy on a cell phone using compact, light-weight and cost-effective opto-fluidic attachments integrated onto the camera module of a smartphone. In our cell-phone based opto-fluidic imaging cytometry design, fluorescently labeled cells are delivered into the imaging area using a disposable micro-fluidic chip that is positioned above the existing camera unit of the cell phone. Battery powered light-emitting diodes (LEDs) are butt-coupled to the sides of this micro-fluidic chip without any lenses, which effectively acts as a multimode slab waveguide, where the excitation light is guided to excite the fluorescent targets within the micro-fluidic chip. Since the excitation light propagates perpendicular to the detection path, an inexpensive plastic absorption filter is able to reject most of the scattered light and create a decent dark-field background for fluorescent imaging. With this excitation geometry, the cell-phone camera can record fluorescent movies of the particles/cells as they are flowing through the microchannel. The digital frames of these fluorescent movies are then rapidly processed to quantify the count and the density of the labeled particles/cells within the solution under test. With a similar opto-fluidic design, we have recently demonstrated imaging and automated counting of stationary blood cells (e.g., labeled white blood cells or unlabeled red blood cells) loaded within a disposable cell counting chamber. We tested the performance of this cell-phone based imaging cytometry and blood analysis platform

  11. Large Volume, Optical and Opto-Mechanical Metrology Techniques for ISIM on JWST

    NASA Technical Reports Server (NTRS)

    Hadjimichael, Theo

    2015-01-01

    The final, flight build of the Integrated Science Instrument Module (ISIM) element of the James Webb Space Telescope is the culmination of years of work across many disciplines and partners. This paper covers the large volume, ambient, optical and opto-mechanical metrology techniques used to verify the mechanical integration of the flight instruments in ISIM, including optical pupil alignment. We present an overview of ISIM's integration and test program, which is in progress, with an emphasis on alignment and optical performance verification. This work is performed at NASA Goddard Space Flight Center, in close collaboration with the European Space Agency, the Canadian Space Agency, and the Mid-Infrared Instrument European Consortium.

  12. Contactless automated manipulation of mesoscale objects using opto-fluidic actuation and visual servoing.

    PubMed

    Vela, Emir; Hafez, Moustapha; Régnier, Stéphane

    2014-05-01

    This work describes an automated opto-fluidic system for parallel non-contact manipulation of microcomponents. The strong dynamics of laser-driven thermocapillary flows were used to drag microcomponents at high speeds. High-speed flows allowed to manipulate micro-objects in a parallel manner only using a single laser and a mirror scanner. An automated process was implemented using visual servoing with a high-speed camera in order to achieve accurately parallel manipulation. Automated manipulation of two glass beads of 30 up to 300 μm in diameter moving in parallel at speeds in the range of mm/s was demonstrated.

  13. Interactive actuation of multiple opto-thermocapillary flow-addressed bubble microrobots

    PubMed Central

    Hu, Wenqi; Fan, Qihui; Ohta, Aaron T

    2014-01-01

    Opto-thermocapillary flow-addressed bubble (OFB) microrobots are a potential tool for the efficient transportation of micro-objects. This microrobot system uses light patterns to generate thermal gradients within a liquid medium, creating thermocapillary forces that actuate the bubble microrobots. An interactive control system that includes scanning mirrors and a touchscreen interface was developed to address up to ten OFB microrobots. Using this system, the parallel and cooperative transportation of 20-μm-diameter polystyrene beads was demonstrated. PMID:25678988

  14. MTF evaluation of white pixel sensors

    NASA Astrophysics Data System (ADS)

    Lindner, Albrecht; Atanassov, Kalin; Luo, Jiafu; Goma, Sergio

    2015-01-01

    We present a methodology to compare image sensors with traditional Bayer RGB layouts to sensors with alternative layouts containing white pixels. We focused on the sensors' resolving powers, which we measured in the form of a modulation transfer function for variations in both luma and chroma channels. We present the design of the test chart, the acquisition of images, the image analysis, and an interpretation of results. We demonstrate the approach at the example of two sensors that only differ in their color filter arrays. We confirmed that the sensor with white pixels and the corresponding demosaicing result in a higher resolving power in the luma channel, but a lower resolving power in the chroma channels when compared to the traditional Bayer sensor.

  15. Advanced monolithic pixel sensors using SOI technology

    NASA Astrophysics Data System (ADS)

    Miyoshi, Toshinobu; Arai, Yasuo; Asano, Mari; Fujita, Yowichi; Hamasaki, Ryutaro; Hara, Kazuhiko; Honda, Shunsuke; Ikegami, Yoichi; Kurachi, Ikuo; Mitsui, Shingo; Nishimura, Ryutaro; Tauchi, Kazuya; Tobita, Naoshi; Tsuboyama, Toru; Yamada, Miho

    2016-07-01

    We are developing advanced pixel sensors using silicon-on-insulator (SOI) technology. A SOI wafer is used; top silicon is used for electric circuit and bottom silicon is used as a sensor. Target applications are high-energy physics, X-ray astronomy, material science, non-destructive inspection, medical application and so on. We have developed two integration-type pixel sensors, FPIXb and INTPIX7. These sensors were processed on single SOI wafers with various substrates in n- or p-type and double SOI wafers. The development status of double SOI sensors and some up-to-date test results of n-type and p-type SOI sensors are shown.

  16. Transmission and opto-mechanical performance of the liquid lens coupling in the Robert Stobie Spectrograph on SALT

    NASA Astrophysics Data System (ADS)

    Strydom, Ockert J.; Depagne, Éric; O'Donoghue, Darragh; Wilkinson, Martin; Lochner, Wouter; Love, Jonathan; Crause, Lisa; Brink, Janus; Nordsieck, Kenneth H.; Schier, J. Alan

    2016-07-01

    Liquid lens coupling provides excellent transmission efficiency when compared to multilayer coatings especially for applications where broadband transmission is required. However, long term reliability of liquid coupling is difficult to achieve. This is typically due to chemical compatibility issues affecting both the optical transmission and the integrity of the opto-mechanical support. As part of a recent service of the Robert Stobie Spectrograph on SALT we had the opportunity to study these problems further and in this paper we provide analysis of problems identified and some solutions to prevent them. We also present general guidelines which could aid future opto-mechanical designs for liquid coupling of lenses.

  17. The Silicon Pixel Detector for ALICE Experiment

    SciTech Connect

    Fabris, D.; Bombonati, C.; Dima, R.; Lunardon, M.; Moretto, S.; Pepato, A.; Bohus, L. Sajo; Scarlassara, F.; Segato, G.; Shen, D.; Turrisi, R.; Viesti, G.; Anelli, G.; Boccardi, A.; Burns, M.; Campbell, M.; Ceresa, S.; Conrad, J.; Kluge, A.; Kral, M.

    2007-10-26

    The Inner Tracking System (ITS) of the ALICE experiment is made of position sensitive detectors which have to operate in a region where the track density may be as high as 50 tracks/cm{sup 2}. To handle such densities detectors with high precision and granularity are mandatory. The Silicon Pixel Detector (SPD), the innermost part of the ITS, has been designed to provide tracking information close to primary interaction point. The assembly of the entire SPD has been completed.

  18. The Belle II DEPFET pixel detector

    NASA Astrophysics Data System (ADS)

    Moser, Hans-Günther

    2016-09-01

    The Belle II experiment at KEK (Tsukuba, Japan) will explore heavy flavour physics (B, charm and tau) at the starting of 2018 with unprecedented precision. Charged particles are tracked by a two-layer DEPFET pixel device (PXD), a four-layer silicon strip detector (SVD) and the central drift chamber (CDC). The PXD will consist of two layers at radii of 14 mm and 22 mm with 8 and 12 ladders, respectively. The pixel sizes will vary, between 50 μm×(55-60) μm in the first layer and between 50 μm×(70-85) μm in the second layer, to optimize the charge sharing efficiency. These innermost layers have to cope with high background occupancy, high radiation and must have minimal material to reduce multiple scattering. These challenges are met using the DEPFET technology. Each pixel is a FET integrated on a fully depleted silicon bulk. The signal charge collected in the 'internal gate' modulates the FET current resulting in a first stage amplification and therefore very low noise. This allows very thin sensors (75 μm) reducing the overall material budget of the detector (0.21% X0). Four fold multiplexing of the column parallel readout allows read out a full frame of the pixel matrix in only 20 μs while keeping the power consumption low enough for air cooling. Only the active electronics outside the detector acceptance has to be cooled actively with a two phase CO2 system. Furthermore the DEPFET technology offers the unique feature of an electronic shutter which allows the detector to operate efficiently in the continuous injection mode of superKEKB.

  19. Local Histograms for Per-Pixel Classification

    DTIC Science & Technology

    2012-03-01

    Domain-Knowledge-Inspired Math - ematical Framework for the Description and Classification of H&E Stained Histopathology Images,” Proceedings of SPIE, 8138... computed over discrete images as the number of pixels in a particular bin. In order to obtain a “density” independent of the bin-width, one can divide the...Notes in Computer Science , 5112: 688–696 (2008). [12] van Ginneken, Bram and Bart M. ter Haar Romeny. “Applications of Locally Orderless Images

  20. Photovoltaic Retinal Prosthesis with High Pixel Density

    PubMed Central

    Mathieson, Keith; Loudin, James; Goetz, Georges; Huie, Philip; Wang, Lele; Kamins, Theodore I.; Galambos, Ludwig; Smith, Richard; Harris, James S.; Sher, Alexander; Palanker, Daniel

    2012-01-01

    Retinal degenerative diseases lead to blindness due to loss of the “image capturing” photoreceptors, while neurons in the “image processing” inner retinal layers are relatively well preserved. Electronic retinal prostheses seek to restore sight by electrically stimulating surviving neurons. Most implants are powered through inductive coils, requiring complex surgical methods to implant the coil-decoder-cable-array systems, which deliver energy to stimulating electrodes via intraocular cables. We present a photovoltaic subretinal prosthesis, in which silicon photodiodes in each pixel receive power and data directly through pulsed near-infrared illumination and electrically stimulate neurons. Stimulation was produced in normal and degenerate rat retinas, with pulse durations from 0.5 to 4 ms, and threshold peak irradiances from 0.2 to 10 mW/mm2, two orders of magnitude below the ocular safety limit. Neural responses were elicited by illuminating a single 70 μm bipolar pixel, demonstrating the possibility of a fully-integrated photovoltaic retinal prosthesis with high pixel density. PMID:23049619

  1. Soil moisture variability within remote sensing pixels

    SciTech Connect

    Charpentier, M.A.; Groffman, P.M. )

    1992-11-30

    This work is part of the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), an international land-surface-atmosphere experiment aimed at improving the way climate models represent energy, water, heat, and carbon exchanges, and improving the utilization of satellite based remote sensing to monitor such parameters. This paper addresses the question of soil moisture variation within the field of view of a remote sensing pixel. Remote sensing is the only practical way to sense soil moisture over large areas, but it is known that there can be large variations of soil moisture within the field of view of a pixel. The difficulty with this is that many processes, such as gas exchange between surface and atmosphere can vary dramatically with moisture content, and a small wet spot, for example, can have a dramatic impact on such processes, and thereby bias remote sensing data results. Here the authors looked at the impact of surface topography on the level of soil moisture, and the interaction of both on the variability of soil moisture sensed by a push broom microwave radiometer (PBMR). In addition the authors looked at the question of whether variations of soil moisture within pixel size areas could be used to assign errors to PBMR generated soil moisture data.

  2. Photovoltaic retinal prosthesis with high pixel density

    NASA Astrophysics Data System (ADS)

    Mathieson, Keith; Loudin, James; Goetz, Georges; Huie, Philip; Wang, Lele; Kamins, Theodore I.; Galambos, Ludwig; Smith, Richard; Harris, James S.; Sher, Alexander; Palanker, Daniel

    2012-06-01

    Retinal degenerative diseases lead to blindness due to loss of the `image capturing' photoreceptors, while neurons in the `image-processing' inner retinal layers are relatively well preserved. Electronic retinal prostheses seek to restore sight by electrically stimulating the surviving neurons. Most implants are powered through inductive coils, requiring complex surgical methods to implant the coil-decoder-cable-array systems that deliver energy to stimulating electrodes via intraocular cables. We present a photovoltaic subretinal prosthesis, in which silicon photodiodes in each pixel receive power and data directly through pulsed near-infrared illumination and electrically stimulate neurons. Stimulation is produced in normal and degenerate rat retinas, with pulse durations of 0.5-4 ms, and threshold peak irradiances of 0.2-10 mW mm-2, two orders of magnitude below the ocular safety limit. Neural responses were elicited by illuminating a single 70 µm bipolar pixel, demonstrating the possibility of a fully integrated photovoltaic retinal prosthesis with high pixel density.

  3. Status of the CMS pixel project

    SciTech Connect

    Uplegger, Lorenzo; /Fermilab

    2008-01-01

    The Compact Muon Solenoid Experiment (CMS) will start taking data at the Large Hadron Collider (LHC) in 2008. The closest detector to the interaction point is the silicon pixel detector which is the heart of the tracking system. It consists of three barrel layers and two pixel disks on each side of the interaction point for a total of 66 million channels. Its proximity to the interaction point means there will be very large particle fluences and therefore a radiation-tolerant design is necessary. The pixel detector will be crucial to achieve a good vertex resolution and will play a key role in pattern recognition and track reconstruction. The results from test beam runs prove that the expected performances can be achieved. The detector is currently being assembled and will be ready for insertion into CMS in early 2008. During the assembly phase, a thorough electronic test is being done to check the functionality of each channel to guarantee the performance required to achieve the physics goals. This report will present the final detector design, the status of the production as well as results from test beam runs to validate the expected performance.

  4. CMOS Active Pixel Sensor Technology and Reliability Characterization Methodology

    NASA Technical Reports Server (NTRS)

    Chen, Yuan; Guertin, Steven M.; Pain, Bedabrata; Kayaii, Sammy

    2006-01-01

    This paper describes the technology, design features and reliability characterization methodology of a CMOS Active Pixel Sensor. Both overall chip reliability and pixel reliability are projected for the imagers.

  5. A PFM based digital pixel with off-pixel residue measurement for 15μm pitch MWIR FPAs

    NASA Astrophysics Data System (ADS)

    Abbasi, Shahbaz; Shafique, Atia; Galioglu, Arman; Ceylan, Omer; Yazici, Melik; Gurbuz, Yasar

    2016-05-01

    Digital pixels based on pulse frequency modulation (PFM) employ counting techniques to achieve very high charge handling capability compared to their analog counterparts. Moreover, extended counting methods making use of leftover charge (residue) on the integration capacitor help improve the noise performance of these pixels. However, medium wave infrared (MWIR) focal plane arrays (FPAs) having smaller pixel pitch are constrained in terms of pixel area which makes it difficult to add extended counting circuitry to the pixel. Thus, this paper investigates the performance of digital pixels employing off-pixel residue measurement. A circuit prototype of such a pixel has been designed for 15μm pixel pitch and fabricated in 90nm CMOS. The prototype is composed of a pixel front-end based on a PFM loop. The frontend is a modified version of conventional design providing a means for buffering the signal that needs to be converted to a digital value by an off-pixel ADC. The pixel has an integration phase and a residue measurement phase. Measured integration performance of the pixel has been reported in this paper for various detector currents and integration times.

  6. PIXELS: Using field-based learning to investigate students' concepts of pixels and sense of scale

    NASA Astrophysics Data System (ADS)

    Pope, A.; Tinigin, L.; Petcovic, H. L.; Ormand, C. J.; LaDue, N.

    2015-12-01

    Empirical work over the past decade supports the notion that a high level of spatial thinking skill is critical to success in the geosciences. Spatial thinking incorporates a host of sub-skills such as mentally rotating an object, imagining the inside of a 3D object based on outside patterns, unfolding a landscape, and disembedding critical patterns from background noise. In this study, we focus on sense of scale, which refers to how an individual quantified space, and is thought to develop through kinesthetic experiences. Remote sensing data are increasingly being used for wide-reaching and high impact research. A sense of scale is critical to many areas of the geosciences, including understanding and interpreting remotely sensed imagery. In this exploratory study, students (N=17) attending the Juneau Icefield Research Program participated in a 3-hour exercise designed to study how a field-based activity might impact their sense of scale and their conceptions of pixels in remotely sensed imagery. Prior to the activity, students had an introductory remote sensing lecture and completed the Sense of Scale inventory. Students walked and/or skied the perimeter of several pixel types, including a 1 m square (representing a WorldView sensor's pixel), a 30 m square (a Landsat pixel) and a 500 m square (a MODIS pixel). The group took reflectance measurements using a field radiometer as they physically traced out the pixel. The exercise was repeated in two different areas, one with homogenous reflectance, and another with heterogeneous reflectance. After the exercise, students again completed the Sense of Scale instrument and a demographic survey. This presentation will share the effects and efficacy of the field-based intervention to teach remote sensing concepts and to investigate potential relationships between students' concepts of pixels and sense of scale.

  7. Ag nanoparticles/PPV composite nanofibers with high and sensitive opto-electronic response

    NASA Astrophysics Data System (ADS)

    Chen, Jinfeng; Yang, Peipei; Wang, Chunjiao; Zhan, Sumei; Zhang, Lianji; Huang, Zonghao; Li, Wenwen; Wang, Cheng; Jiang, Zijiang; Shao, Chen

    2011-12-01

    The novel Ag nanoparticles/poly( p-phenylene vinylene) [PPV] composite nanofibers were prepared by electrospinning. The transmission electron microscope image shows that the average diameter of composite fibers is about 500 nm and Ag nanoparticles are uniformly dispersed in the PPV matrix with an average diameter of about 25 nm. The Fourier transform infrared spectra suggest that there could be a coordination effect to a certain extent between the Ag atom and the π system of PPV, which is significantly favorable for the dissociation of photoexcitons and the charge transfer at the interface between the Ag nanoparticle and the PPV. The Au top electrode device of the single Ag/PPV composite nanofiber exhibits high and sensitive opto-electronic responses. Under light illumination of 5.76 mW/cm2 and voltage of 20 V, the photocurrent is over three times larger than the dark current under same voltage, which indicates that this kind of composite fiber is an excellent opto-electronic nanomaterial.

  8. Experiences with Opto-Mechanical Systems that Affect Optical Surfaces at the Sub-Nanometer Level

    SciTech Connect

    Hale, L C; Taylor, J S

    2008-04-03

    Projection optical systems built for Extreme Ultraviolet Lithography (EUVL) demonstrated the ability to produce, support and position reflective optical surfaces for achieving transmitted wavefront errors of 1 nm or less. Principal challenges included optical interferometry, optical manufacturing processes, multi-layer coating technology and opto mechanics. Our group was responsible for designing, building and aligning two different projection optical systems: a full-field, 0.1 NA, four-mirror system for 70 nm features and a small-field, 0.3 NA, two-mirror system for 30 nm features. Other than physical size and configuration, the two systems were very similar in the way they were designed, built and aligned. A key difference exists in the optic mounts, driven primarily by constraints from the metrology equipment used by different optics manufacturers. As mechanical stability and deterministic position control of optics will continue to play an essential role in future systems, we focus our discussion on opto-mechanics and primarily the optic mounts.

  9. Opto-mechanical modeling of the Herschel Space Telescope at ESA/ESTEC

    NASA Astrophysics Data System (ADS)

    Fransen, S.; Doyle, D.; Catanzaro, B.

    2011-09-01

    In this paper the opto-mechanical modeling of the Herschel infrared space telescope at ESA/ESTEC is presented. The aim of the paper is to give an overview of all modeling activities that took place between 2006 and 2010. In 2006 ESA commissioned a Tiger Team to review the discrepancy between the prediction and measurement of the change in telescope back focal length of the Herschel infrared space telescope. The understanding of the discrepancy was essential since the telescope did not have a refocusing mechanism and hence had to be shimmed to the focus position at cryogenic operational temperature. A team of 16 engineers and scientists collocated at ESA/ESTEC to review the finite element models, optical models and test data used for the prediction of the telescope back focal length. The methodology of prediction, the uncertainties and the obtained results were critically assessed. The team used various modeling techniques including paraxial optical models, first order linear thermal expansion models, full system and metrology ray tracing, deterministic and stochastic thermo-elastic finite element analyses. The opto-mechanical analysis techniques, assumptions and results are discussed. In addition the impact of new measurements of coefficients of thermal expansion, performed after shimming of the telescope flight model, are addressed.

  10. An opto-electronic joint detection system based on DSP aiming at early cervical cancer screening

    NASA Astrophysics Data System (ADS)

    Wang, Weiya; Jia, Mengyu; Gao, Feng; Yang, Lihong; Qu, Pengpeng; Zou, Changping; Liu, Pengxi; Zhao, Huijuan

    2015-02-01

    The cervical cancer screening at a pre-cancer stage is beneficial to reduce the mortality of women. An opto-electronic joint detection system based on DSP aiming at early cervical cancer screening is introduced in this paper. In this system, three electrodes alternately discharge to the cervical tissue and three light emitting diodes in different wavelengths alternately irradiate the cervical tissue. Then the relative optical reflectance and electrical voltage attenuation curve are obtained by optical and electrical detection, respectively. The system is based on DSP to attain the portable and cheap instrument. By adopting the relative reflectance and the voltage attenuation constant, the classification algorithm based on Support Vector Machine (SVM) discriminates abnormal cervical tissue from normal. We use particle swarm optimization to optimize the two key parameters of SVM, i.e. nuclear factor and cost factor. The clinical data were collected on 313 patients to build a clinical database of tissue responses under optical and electrical stimulations with the histopathologic examination as the gold standard. The classification result shows that the opto-electronic joint detection has higher total coincidence rate than separate optical detection or separate electrical detection. The sensitivity, specificity, and total coincidence rate increase with the increasing of sample numbers in the training set. The average total coincidence rate of the system can reach 85.1% compared with the histopathologic examination.

  11. Nano opto-mechanical systems (NOMS) as a proposal for tactile displays

    NASA Astrophysics Data System (ADS)

    Campo, E. M.; Roig, J.; Roeder, B.; Wenn, D.; Mamojka, B.; Omastova, M.; Terentjev, E. M.; Esteve, J.

    2011-10-01

    For over a decade, special emphasis has been placed in the convergence of different fields of science and technology, in an effort to serve human needs by way of enhancing human capabilities. The convergence of the Nano-Bio-Info-Cogni (NBIC) quartet will provide unique solutions to specific needs. This is the case of, Nano-opto mechanical Systems (NOMS), presented as a solution to tactile perception, both for the visually-impaired and for the general public. NOMS, based on photoactive polymer actuators and devices, is a much sought-after technology. In this scheme, light sources promote mechanical actuation producing a variety of nano-opto mechanical systems such as nano-grippers. In this paper, we will provide a series of specifications that the NOMS team is targeting towards the development of a tactile display using optically-activated smart materials. Indeed, tactile displays remain mainly mechanical, compromising reload speeds and resolution which inhibit 3D tactile representation of web interfaces. We will also discuss how advantageous NOMS tactile displays could be for the general public. Tactile processing based on stimulation delivered through the NOMS tablet, will be tested using neuropsychology methods, in particular event-related brain potentials. Additionally, the NOMS tablet will be instrumental to the development of basic neuroscience research.

  12. Experimental validation of opto-thermo-elastic modeling in OOFELIE multiphysics

    NASA Astrophysics Data System (ADS)

    Mazzoli, Alexandra; Saint-Georges, Philippe; Orban, Anne; Ruess, Jean-Sébastien; Loicq, Jérôme; Barbier, Christian; Stockman, Yvan; Georges, Marc; Nachtergaele, Philippe; Paquay, Stéphane; De Vincenzo, Pascal

    2011-10-01

    The objective of this work is to demonstrate the correlation between a simple laboratory test bench case and the predictions of the OOFELIE Multiphysics software in order to deduce modeling guidelines and improvements. For that purpose two optical systems have been analyzed. The first one is a spherical lens fixed in an aluminium barrel, which is the simplest structure found in an opto-mechanical system. In this study, material characteristics are assumed to be well known: BK7 and aluminium have been retained. Temperature variations between 0 and +60°C from ambient have been applied to the samples. The second system is a YAG laser bar heated by means of a dedicated oven. For the two test benches thermo-elastic distortions have been measured using a Fizeau interferometer. This sensor measures wavefront error in the range of 20 nm to 1 μm without physical contact with the opto-mechanical system. For the YAG bar, birefringence and polarization measurements have also been performed using a polarimetric bench. The tests results have been compared to the predictions obtained by OOFELIE Multiphysics which is a simulation software dedicated to multiphysics coupled problems involving optics, mechanics, thermal physics, electricity, electromagnetism, acoustics and hydrodynamics. From this comparison modeling guidelines have been issued with the aim of improving the accuracy of computed thermo-elastic distortions and their impact on the optical performances.

  13. Opto-mechanical design of an image slicer for the GRIS spectrograph at GREGOR

    NASA Astrophysics Data System (ADS)

    Vega Reyes, N.; Esteves, M. A.; Sánchez-Capuchino, J.; Salaun, Y.; López, R. L.; Gracia, F.; Estrada Herrera, P.; Grivel, C.; Vaz Cedillo, J. J.; Collados, M.

    2016-07-01

    An image slicer has been proposed for the Integral Field Spectrograph [1] of the 4-m European Solar Telescope (EST) [2] The image slicer for EST is called MuSICa (Multi-Slit Image slicer based on collimator-Camera) [3] and it is a telecentric system with diffraction limited optical quality offering the possibility to obtain high resolution Integral Field Solar Spectroscopy or Spectro-polarimetry by coupling a polarimeter after the generated slit (or slits). Considering the technical complexity of the proposed Integral Field Unit (IFU), a prototype has been designed for the GRIS spectrograph at GREGOR telescope at Teide Observatory (Tenerife), composed by the optical elements of the image slicer itself, a scanning system (to cover a larger field of view with sequential adjacent measurements) and an appropriate re-imaging system. All these subsystems are placed in a bench, specially designed to facilitate their alignment, integration and verification, and their easy installation in front of the spectrograph. This communication describes the opto-mechanical solution adopted to upgrade GRIS while ensuring repeatability between the observational modes, IFU and long-slit. Results from several tests which have been performed to validate the opto-mechanical prototypes are also presented.

  14. Invited Article: Real-time sensing of flowing nanoparticles with electro-opto-mechanics

    NASA Astrophysics Data System (ADS)

    Suh, Jeewon; Han, Kewen; Peterson, Christopher W.; Bahl, Gaurav

    2017-01-01

    High-Q optical resonators allow label-free detection of individual nanoparticles through perturbation of optical signatures but have practical limitations due to reliance on random diffusion to deliver particles to the sensing region. We have recently developed microfluidic optomechanical resonators that allow detection of free-flowing particles in fluid media with near perfect detection efficiency, without requiring labeling, binding, or direct access to the optical mode. Rapid detection of single particles is achieved through a long-range optomechanical interaction in which modification of the resonator vibrational modes during particle transits influences the scattered light spectra from the resonator. Here, we present a hybrid electro-opto-mechanical technique for substantially increasing the bandwidth of these opto-mechano-fluidic sensors, enabling real-time operation. The demonstrated improvements are obtained through high bandwidth lock-in measurement of the optical modulation that is induced by actuating the vibrational mode electrostatically at a fixed frequency. The presented system demonstrates temporal resolution of better than 20 μs (50 000 events/s) with particle sensing resolution (i.e., the particle size noise floor) down to 490 nm, operating in the air without any stabilization or environmental control. Our technique significantly enhances the sensing capabilities of high-Q optical resonators into the mechanics domain and allows extremely high-throughput analysis of large nanoparticle populations.

  15. Opto-acoustic sensing of fluids and bioparticles with optomechanofluidic resonators

    NASA Astrophysics Data System (ADS)

    Zhu, K.; Han, K.; Carmon, T.; Fan, X.; Bahl, G.

    2014-09-01

    Opto-mechano-fluidic resonators (OMFRs) are a unique optofluidics platform that can measure the acoustic properties of fluids and bioanalytes in a fully-contained microfluidic system. By confining light in ultra-high-Q whispering gallery modes of OMFRs, optical forces such as radiation pressure and electrostriction can be used to actuate and sense structural mechanical vibrations spanning MHz to GHz frequencies. These vibrations are hybrid fluid-shell modes that entrain any bioanalyte present inside. As a result, bioanalytes can now reflect their acoustic properties on the optomechanical vibrational spectrum of the device, in addition to optical property measurements with existing optofluidics techniques. In this work, we investigate acoustic sensing capabilities of OMFRs using computational eigenfrequency analysis. We analyze the OMFR eigenfrequency sensitivity to bulk fluid-phase materials as well as nanoparticles, and propose methods to extract multiple acoustic parameters from multiple vibrational modes. The new informational degrees-of-freedom provided by such opto-acoustic measurements could lead to surprising new sensor applications in the near future.

  16. Measurements with MÖNCH, a 25 μm pixel pitch hybrid pixel detector

    NASA Astrophysics Data System (ADS)

    Ramilli, M.; Bergamaschi, A.; Andrae, M.; Brückner, M.; Cartier, S.; Dinapoli, R.; Fröjdh, E.; Greiffenberg, D.; Hutwelker, T.; Lopez-Cuenca, C.; Mezza, D.; Mozzanica, A.; Ruat, M.; Redford, S.; Schmitt, B.; Shi, X.; Tinti, G.; Zhang, J.

    2017-01-01

    MÖNCH is a hybrid silicon pixel detector based on charge integration and with analog readout, featuring a pixel size of 25×25 μm2. The latest working prototype consists of an array of 400×400 identical pixels for a total active area of 1×1 cm2. Its design is optimized for the single photon regime. An exhaustive characterization of this large area prototype has been carried out in the past months, and it confirms an ENC in the order of 35 electrons RMS and a dynamic range of ~4×12 keV photons in high gain mode, which increases to ~100×12 keV photons with the lowest gain setting. The low noise levels of MÖNCH make it a suitable candidate for X-ray detection at energies around 1 keV and below. Imaging applications in particular can benefit significantly from the use of MÖNCH: due to its extremely small pixel pitch, the detector intrinsically offers excellent position resolution. Moreover, in low flux conditions, charge sharing between neighboring pixels allows the use of position interpolation algorithms which grant a resolution at the micrometer-level. Its energy reconstruction and imaging capabilities have been tested for the first time at a low energy beamline at PSI, with photon energies between 1.75 keV and 3.5 keV, and results will be shown.

  17. Active pixel sensor pixel having a photodetector whose output is coupled to an output transistor gate

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Nakamura, Junichi (Inventor); Kemeny, Sabrina E. (Inventor)

    2005-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node. There is also a readout circuit, part of which can be disposed at the bottom of each column of cells and be common to all the cells in the column. A Simple Floating Gate (SFG) pixel structure could also be employed in the imager to provide a non-destructive readout and smaller pixel sizes.

  18. How many pixels does it take to make a good 4"×6" print? Pixel count wars revisited

    NASA Astrophysics Data System (ADS)

    Kriss, Michael A.

    2011-01-01

    In the early 1980's the future of conventional silver-halide photographic systems was of great concern due to the potential introduction of electronic imaging systems then typified by the Sony Mavica analog electronic camera. The focus was on the quality of film-based systems as expressed in the number of equivalent number pixels and bits-per-pixel, and how many pixels would be required to create an equivalent quality image from a digital camera. It was found that 35-mm frames, for ISO 100 color negative film, contained equivalent pixels of 12 microns for a total of 18 million pixels per frame (6 million pixels per layer) with about 6 bits of information per pixel; the introduction of new emulsion technology, tabular AgX grains, increased the value to 8 bit per pixel. Higher ISO speed films had larger equivalent pixels, fewer pixels per frame, but retained the 8 bits per pixel. Further work found that a high quality 3.5" x 5.25" print could be obtained from a three layer system containing 1300 x 1950 pixels per layer or about 7.6 million pixels in all. In short, it became clear that when a digital camera contained about 6 million pixels (in a single layer using a color filter array and appropriate image processing) that digital systems would challenge and replace conventional film-based system for the consumer market. By 2005 this became the reality. Since 2005 there has been a "pixel war" raging amongst digital camera makers. The question arises about just how many pixels are required and are all pixels equal? This paper will provide a practical look at how many pixels are needed for a good print based on the form factor of the sensor (sensor size) and the effective optical modulation transfer function (optical spread function) of the camera lens. Is it better to have 16 million, 5.7-micron pixels or 6 million 7.8-micron pixels? How does intrinsic (no electronic boost) ISO speed and exposure latitude vary with pixel size? A systematic review of these issues will

  19. Opto-mechanical subsystem of a 10 micrometer wavelength receiver terminal. Waveguide laser local oscillator. Servo system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    An engineering model opto-mechanical subsystem for a 10.6-micrometer laser heterodyne receiver is developed, and a CO2 waveguide local oscillator and servo electronics are provided for the receiver. Design goals are presented for the subsystems and overall package design is described. Thermal and mechanical distortion loading tests were performed and the results are included.

  20. Low power consumption and continuously tunable all-optical microwave filter based on an opto-mechanical microring resonator.

    PubMed

    Liu, Li; Yang, Yue; Li, Zhihua; Jin, Xing; Mo, Wenqin; Liu, Xing

    2017-01-23

    We propose and experimentally demonstrate a continuously tunable all-optical microwave filter using a silicon opto-mechanical microring resonator (MRR). By finely adjusting the pump light with submilliwatt power level, transmission spectrum of the MRR could be continuously shifted based on the nonlinear effects, including the opto-mechanical effect and thermo-optic effect. Therefore, in the case of optical single sideband (OSSB) modulation, the frequency intervals between the optical carrier (near one MRR resonance) and the corresponding resonance could be flexibly manipulated, which is the critical factor to achieve continuously tunable microwave photonic filter (MPF). In the experiment, the central frequency of the MPF could be continuously tuned from 6 GHz to 19 GHz with the pump power lower than -2.5 dBm. The proposed opto-mechanical device is competent to process microwave signals with dominant advantages, such as compact footprint, all-optical control and low power consumption. In the future, using light to control light, the opto-mechanical structure on silicon platforms might have many other potential applications in microwave systems, such as microwave switch.

  1. Pixel-Level Simulation of Imaging Data

    NASA Astrophysics Data System (ADS)

    Stoughton, C.; Kuropatkin, N. P.; Neilsen, E., Jr.; Harms, D. C.

    2007-10-01

    We are preparing a set of Java packages to facilitate the design and operation of imaging surveys. The packages use shapelets to describe shapes of astronomical sources, optical distortions, and shear from weak gravitational lensing. We introduce noise, bad pixels, cosmic rays, the pupil image, saturation, and other observational effects. A set of utility classes handles I/O, plotting, and interfaces to existing packages: nom.tam.fits for FITS I/O; uk.ac.starlink.table for tables; and cern.colt for algorithms. The packages have been used to generate images for the Dark Energy Survey data challenges, and will be used by SNAP to continue evaluating its design.

  2. Small pixel uncooled imaging FPAs and applications

    NASA Astrophysics Data System (ADS)

    Blackwell, Richard; Franks, Glen; Lacroix, Daniel; Hyland, Sandra; Murphy, Robert

    2010-04-01

    BAE Systems continues to make dramatic progress in uncooled microbolometer sensors and applications. This paper will review the latest advancements in microbolometer technology at BAE Systems, including the development status of 17 micrometer pixel pitch detectors and imaging modules which are entering production and will be finding their way into BAE Systems products and applications. Benefits include increased die per wafer and potential benefits to SWAP for many applications. Applications include thermal weapons sights, thermal imaging modules for remote weapon stations, vehicle situational awareness sensors and mast/pole mounted sensors.

  3. Active pixel sensor array with electronic shuttering

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor)

    2002-01-01

    An active pixel cell includes electronic shuttering capability. The cell can be shuttered to prevent additional charge accumulation. One mode transfers the current charge to a storage node that is blocked against accumulation of optical radiation. The charge is sampled from a floating node. Since the charge is stored, the node can be sampled at the beginning and the end of every cycle. Another aspect allows charge to spill out of the well whenever the charge amount gets higher than some amount, thereby providing anti blooming.

  4. A neighbor pixel communication filtering structure for Dynamic Vision Sensors

    NASA Astrophysics Data System (ADS)

    Xu, Yuan; Liu, Shiqi; Lu, Hehui; Zhang, Zilong

    2017-02-01

    For Dynamic Vision Sensors (DVS), thermal noise and junction leakage current induced Background Activity (BA) is the major cause of the deterioration of images quality. Inspired by the smoothing filtering principle of horizontal cells in vertebrate retina, A DVS pixel with Neighbor Pixel Communication (NPC) filtering structure is proposed to solve this issue. The NPC structure is designed to judge the validity of pixel's activity through the communication between its 4 adjacent pixels. The pixel's outputs will be suppressed if its activities are determined not real. The proposed pixel's area is 23.76×24.71μm2 and only 3ns output latency is introduced. In order to validate the effectiveness of the structure, a 5×5 pixel array has been implemented in SMIC 0.13μm CIS process. 3 test cases of array's behavioral model show that the NPC-DVS have an ability of filtering the BA.

  5. Active pixel sensor array with multiresolution readout

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Kemeny, Sabrina E. (Inventor); Pain, Bedabrata (Inventor)

    1999-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node. There is also a readout circuit, part of which can be disposed at the bottom of each column of cells and be common to all the cells in the column. The imaging device can also include an electronic shutter formed on the substrate adjacent the photogate, and/or a storage section to allow for simultaneous integration. In addition, the imaging device can include a multiresolution imaging circuit to provide images of varying resolution. The multiresolution circuit could also be employed in an array where the photosensitive portion of each pixel cell is a photodiode. This latter embodiment could further be modified to facilitate low light imaging.

  6. The Phase1 CMS Pixel detector upgrade

    NASA Astrophysics Data System (ADS)

    Tavolaro, V. R.

    2016-12-01

    The pixel detector of the CMS experiment will be replaced in an extended end-of-year shutdown during winter 2016/2017 with an upgraded one able to cope with peak instantaneous luminosities beyond the nominal LHC instantaneous luminosity of 1 × 1034 cm-2 s-1. Under the conditions expected in the coming years, which will see an increase of a factor two in instantaneous luminosity, the present system would experience a dynamic inefficiency caused mainly by data losses due to buffer overflows. The Phase I upgrade of the CMS pixel detector, described in this paper, will operate at full efficiency at an instantaneous luminosity of 2 × 1034 cm-2 s-1 and beyond, thanks to a new readout chip. The new detector will feature one additional tracking point both in the barrel and in the forward regions, while reducing the material budget as a result of a new CO2 cooling system and optimised layout of the services. In this paper, the design and the technological choices of the Phase I detector will be reviewed and the status of the construction of the detector and the performance of its components will be discussed.

  7. Ultra large mode area pixelated Bragg fiber

    NASA Astrophysics Data System (ADS)

    Yehouessi, J.-P.; Bouwmans, G.; Vanvincq, O.; Cassez, A.; Habert, R.; Quiquempois, Y.; Bigot, L.

    2016-03-01

    We report on the design and the fabrication of a new design of an all-solid Bragg fiber based on the pixelization and heterostructuration of a cladding made of only two high index rings. The thickness of the low index ring as well as the geometry of the heterostructuration (its symmetry and the number of removed pixels) have been chosen to maximize the confinement losses of the Higher Order Modes (HOM) (above 10 dB/m) while keeping the Fundamental Mode (FM) losses low (below 0.1 dB/m). The proposed geometry allows having access to different Mode Field Diameter (MFD) from 54 μm to 60 μm at 1 μm wavelength by drawing the same stack to different fiber (and hence, core) diameters. As a result, a record MFD of 60 μm is reported for a Solid Core Photonic Bandgap Fiber (SC-PBGF) and single-mode behavior is obtained experimentally even for a short fiber length (few tens centimeters) maintained straight.

  8. Silicon pixel R&D for CLIC

    NASA Astrophysics Data System (ADS)

    Munker, M.

    2017-01-01

    Challenging detector requirements are imposed by the physics goals at the future multi-TeV e+ e‑ Compact Linear Collider (CLIC). A single point resolution of 3 μm for the vertex detector and 7 μm for the tracker is required. Moreover, the CLIC vertex detector and tracker need to be extremely light weighted with a material budget of 0.2% X0 per layer in the vertex detector and 1–2% X0 in the tracker. A fast time slicing of 10 ns is further required to suppress background from beam-beam interactions. A wide range of sensor and readout ASIC technologies are investigated within the CLIC silicon pixel R&D effort. Various hybrid planar sensor assemblies with a pixel size of 25×25 μm2 and 55×55 μm2 have been produced and characterised by laboratory measurements and during test-beam campaigns. Experimental and simulation results for thin (50 μm–500 μm) slim edge and active-edge planar, and High-Voltage CMOS sensors hybridised to various readout ASICs (Timepix, Timepix3, CLICpix) are presented.

  9. Serial pixel analog-to-digital converter (ADC)

    NASA Astrophysics Data System (ADS)

    Larson, Eric D.

    2010-02-01

    This method reduces the data path from the counter to the pixel register of the analog-to-digital converter (ADC) from as many as 10 bits to a single bit. The reduction in data path width is accomplished by using a coded serial data stream similar to a pseudo random number (PRN) generator. The resulting encoded pixel data is then decoded into a standard hexadecimal format before storage. The high-speed serial pixel ADC concept is based on the single-slope integrating pixel ADC architecture. Previous work has described a massively parallel pixel readout of a similar architecture. The serial ADC connection is similar to the state-of-the art method with the exception that the pixel ADC register is a shift register and the data path is a single bit. A state-of-the-art individual-pixel ADC uses a single-slope charge integration converter architecture with integral registers and "one-hot" counters. This implies that parallel data bits are routed among the counter and the individual on-chip pixel ADC registers. The data path bit-width to the pixel is therefore equivalent to the pixel ADC bit resolution.

  10. Analysis of pixel circuits in CMOS image sensors

    NASA Astrophysics Data System (ADS)

    Mei, Zou; Chen, Nan; Yao, Li-bin

    2015-04-01

    CMOS image sensors (CIS) have lower power consumption, lower cost and smaller size than CCD image sensors. However, generally CCDs have higher performance than CIS mainly due to lower noise. The pixel circuit used in CIS is the first part of the signal processing circuit and connected to photodiode directly, so its performance will greatly affect the CIS or even the whole imaging system. To achieve high performance, CMOS image sensors need advanced pixel circuits. There are many pixel circuits used in CIS, such as passive pixel sensor (PPS), 3T and 4T active pixel sensor (APS), capacitive transimpedance amplifier (CTIA), and passive pixel sensor (PPS). At first, the main performance parameters of each pixel structure including the noise, injection efficiency, sensitivity, power consumption, and stability of bias voltage are analyzed. Through the theoretical analysis of those pixel circuits, it is concluded that CTIA pixel circuit has good noise performance, high injection efficiency, stable photodiode bias, and high sensitivity with small integrator capacitor. Furthermore, the APS and CTIA pixel circuits are simulated in a standard 0.18-μm CMOS process and using a n-well/p-sub photodiode by SPICE and the simulation result confirms the theoretical analysis result. It shows the possibility that CMOS image sensors can be extended to a wide range of applications requiring high performance.

  11. Enhancement and suppression of opto-acoustic parametric interactions using optical feedback

    SciTech Connect

    Zhang Zhongyang; Zhao Chunnong; Ju, L.; Blair, D. G.

    2010-01-15

    A three mode opto-acoustic parametric amplifier (OAPA) is created when two orthogonal optical modes in a high finesse optical cavity are coupled via an acoustic mode of the cavity mirror. Such interactions are predicted to occur in advanced long baseline gravitational wave detectors. They can have high positive gain, which leads to strong parametric instability. Here we show that an optical feedback scheme can enhance or suppress the parametric gain of an OAPA, allowing exploration of three-mode parametric interactions, especially in cavity systems that have insufficient optical power to achieve spontaneous instability. We derive analytical equations and show that optical feedback is capable of controlling predicted instabilities in advanced gravitational wave detectors within a time scale of 13approx10 s.

  12. Opto-acoustic image fusion technology for diagnostic breast imaging in a feasibility study

    NASA Astrophysics Data System (ADS)

    Zalev, Jason; Clingman, Bryan; Herzog, Don; Miller, Tom; Ulissey, Michael; Stavros, A. T.; Oraevsky, Alexander; Lavin, Philip; Kist, Kenneth; Dornbluth, N. C.; Otto, Pamela

    2015-03-01

    Functional opto-acoustic (OA) imaging was fused with gray-scale ultrasound acquired using a specialized duplex handheld probe. Feasibility Study findings indicated the potential to more accurately characterize breast masses for cancer than conventional diagnostic ultrasound (CDU). The Feasibility Study included OA imagery of 74 breast masses that were collected using the investigational Imagio® breast imaging system. Superior specificity and equal sensitivity to CDU was demonstrated, suggesting that OA fusion imaging may potentially obviate the need for negative biopsies without missing cancers in a certain percentage of breast masses. Preliminary results from a 100 subject Pilot Study are also discussed. A larger Pivotal Study (n=2,097 subjects) is underway to confirm the Feasibility Study and Pilot Study findings.

  13. Integrated opto-microfluidics platforms in lithium niobate crystals for sensing applications

    NASA Astrophysics Data System (ADS)

    Bettella, G.; Pozza, G.; Zaltron, A.; Ciampolillo, M. V.; Argiolas, N.; Sada, C.; Chauvet, M.; Guichardaz, B.

    2015-02-01

    In micro-analytical chemistry and biology applications, droplet microfluidic technology holds great promise for efficient lab-on-chip systems where higher levels of integration of different stages on the same platform is constantly addressed. The possibility of integration of opto-microfluidic functionalities in lithium niobate (LiNbO3) crystals is presented. Microfluidic channels were directly engraved in a LiNbO3 substrate by precision saw cutting, and illuminated by optical waveguides integrated on the same substrate. The morphological characterization of the microfluidic channel and the optical response of the coupled optical waveguide were tested. In particular, the results indicate that the optical properties of the constituents dispersed in the fluid flowing in the microfluidic channel can be monitored in situ, opening to new compact optical sensor prototypes based on droplets generation and optical analysis of the relative constituents.

  14. Application of flexure structures to active and adaptive opto-mechanical mechanisms

    NASA Astrophysics Data System (ADS)

    Zago, Lorenzo; Genequand, Pierre M.; Kjelberg, Ivar; Morschel, Joseph

    1997-03-01

    Active and adaptive structures, also commonly called 'smart' structures, combine in one integrated system various functions such as load carrying and structural function, mechanical (cinematic) functions, sensing, control and actuating. Originally developed for high accuracy opto-mechanical applications, CSEM's technology of flexure structures and flexible mechanisms is particularly suited to solve many structural and mechanical issues found in such active/adaptive mechanisms. The paper illustrates some recent flexure structures developments at CSEM and outlines the comprehensive know-how involved in this technology. This comprises in particular the elaboration of optimal design guidelines, related to the geometry, kinematics and dynamics issues (for instance, the minimization of spurious high frequency effects), the evaluation and predictability of all performance quantities relevant to the utilization of flexure structures in space (reliability, fatigue, static and dynamic modeling, etc.). material issues and manufacturing procedures.

  15. Opto-mechanical design of vacuum laser resonator for the OSQAR experiment

    NASA Astrophysics Data System (ADS)

    Hošek, Jan; Macúchová, Karolina; Nemcová, Šárka; Kunc, Štěpán.; Šulc, Miroslav

    2015-01-01

    This paper gives short overview of laser-based experiment OSQAR at CERN which is focused on search of axions and axion-like particles. The OSQAR experiment uses two experimental methods for axion search - measurement of the ultra-fine vacuum magnetic birefringence and a method based on the "Light shining through the wall" experiment. Because both experimental methods have reached its attainable limits of sensitivity we have focused on designing a vacuum laser resonator. The resonator will increase the number of convertible photons and their endurance time within the magnetic field. This paper presents an opto-mechanical design of a two component transportable vacuum laser resonator. Developed optical resonator mechanical design allows to be used as a 0.8 meter long prototype laser resonator for laboratory testing and after transportation and replacement of the mirrors it can be mounted on the LHC magnet in CERN to form a 20 meter long vacuum laser resonator.

  16. Highly sensitive detection of glucose concentration with opto-fluidics ring resonator

    NASA Astrophysics Data System (ADS)

    Luo, Yunhan; Khaing Oo, Maung Kyaw; Ge, Jia; Chen, Zhe; Fan, Xudong

    2012-06-01

    Noninvasive detection of glucose has been heavily researched in their roles of offering cost-effective, painless, and bloodless monitoring of glucose concentration. In this work, we describe a novel, label-free, and sensitive approach for detecting the glucose concentration in human interstitial fluid samples using the opto-fluidic ring resonator (OFRR). The OFRR incorporates microfluidics and optical ring resonator sensing technology to achieve rapid label-free detection in a small and low-cost platform. In this study, bulk refractive index measurements are presented. Results show that the OFRR is able to detect glucose at medically relevant concentrations in interstitial fluid ranging from 0 to 25 mM, with a detection limit of 0.32 mM, which is lower than clinical requirement by one order of magnitude. Our work is believed to lead to a device that can be used to frequently monitor glucose concentration in a low-cost and painless manner.

  17. Localized Opto-Mechanical Control of Protein Adsorption onto Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    O'Dell, Dakota; Serey, Xavier; Kang, Pilgyu; Erickson, David

    2014-10-01

    Chemical reactions can be described by an energy diagram along a reaction coordinate in which an activation barrier limits the rate at which reactants can be transformed into products. This reaction impedance can be overcome by reducing the magnitude of the barrier through the use of catalysis, increasing the thermal energy of the system, or through macroscopic mechanical processes. Here, we demonstrate direct molecular-scale control of a reaction through the precise application of opto-mechanical work. The method uses optical gradient forces generated in the evanescent field surrounding hybrid photonic-plasmonic structures to drive an otherwise unlikely adsorption reaction between proteins and carbon nanotubes. The adsorption of immunoglobulins on carbon nanotubes is used as a model reaction and investigated with an extended DLVO theory. The technique is also used to force a Förster resonance energy transfer between fluorophores on mismatched immunoglobulin proteins and is expected to lead to novel forms of chemical synthesis.

  18. The contribution of nonlocal electro-opto-thermal interaction to single molecule nonlinear Raman enhancement.

    PubMed

    Tai, Chao-Yi; Yu, Wen-Hsiang

    2013-10-21

    we develop a precise modelling where nonlocal electro-opto-thermal interactions are comprehensively included for the analysis of nonlinear Raman enhancement and plasmonic heating. An interaction enhancement factor G(IEF) is introduced to quantify the coupling between the electromagnetic field and the temperature field which is rarely considered in the estimation of Raman enhancement. For the case of isolated single nanosphere, G(IEF) can be up to ten, indicating a thermal origin which well explains the observed temperature rise, shortened blinking period, and the nonlinearly enhanced Raman cross-section. For the case of nanodimer, the suppression of plasmon heating was analyzed, demonstrating the great capability to mitigate biomolecular degradation and blinking.

  19. Opto-Thermal Transient Emission Radiometry (OTTER) to image diffusion in nails in vivo.

    PubMed

    Xiao, P; Zheng, X; Imhof, R E; Hirata, K; McAuley, W J; Mateus, R; Hadgraft, J; Lane, M E

    2011-03-15

    This work describes the first application of Opto-Thermal Transient Emission Radiometry (OTTER), an infrared remote sensing technique, to probe the extent to which solvents permeate the human nail in vivo. Decanol, glycerol and butyl acetate were selected as model solvents. After application of the solvents, individually, to human volunteers, OTTER was used to depth profile the solvents. The permeation rate of the solvents was ranked as glycerol>decanol>butyl acetate. It is possible that some of the butyl acetate may have evaporated during the experiment. The ability of decanol to extract lipids from biological tissue is also considered. These preliminary results demonstrate the potential of OTTER as a tool to identify optimal excipients with which to target drugs to the nail.

  20. Rapid discrimination of DNA strands using an opto-calorimetric microcantilever sensor.

    PubMed

    Lee, Dongkyu; Hwang, Kyo Seon; Kim, Seonghwan; Thundat, Thomas

    2014-12-21

    A rapid technique for quantitative detection and discrimination of DNA strands without using immobilized probe molecules is demonstrated using an opto-calorimetric, self-powered sensor based on a Pb(Zr(0.52)Ti(0.48))O3 (PZT) microcantilever. Microcalorimetric infrared (IR) spectroscopy provides excellent chemical selectivity based on the unique molecular vibrational characteristics of each nucleotide in the mid IR region. The piezoelectric and pyroelectric properties of the PZT microcantilever were exploited in the quantitative detection and discrimination of adsorbed DNA strands with their spectral characteristics. We report the unique spectral characteristics of different DNA nucleotides that are monitored by wavelength-dependent temperature variations for different relative molar ratio of each nucleotide. This approach offers a fast, label-free technique which is highly sensitive and selective for the detection of single nucleotide differences in DNA strands and has the potential to be used as a rapid prescreening biosensor for various biomolecules.

  1. OptoRadio: a method of wireless communication using orthogonal M-ary PSK (OMPSK) modulation

    NASA Astrophysics Data System (ADS)

    Gaire, Sunil Kumar; Faruque, Saleh; Ahamed, Md. Maruf

    2016-09-01

    Laser based radio communication system, i.e. OptoRadio, using Orthogonal M-ary PSK Modulation scheme is presented in this paper. In this scheme, when a block of data needs to be transmitted, the corresponding block of biorthogonal code is transmitted by means of multi-phase shift keying. At the receiver, two photo diodes are cross coupled. The effect is that the net output power due to ambient light is close to zero. The laser signal is then transmitted only into one of the receivers. With all other signals being cancelled out, the laser signal is an overwhelmingly dominant signal. The detailed design, bit error correction capabilities, and bandwidth efficiency are presented to illustrate the concept.

  2. An opto-magneto-mechanical quantum interface between distant superconducting qubits

    PubMed Central

    Xia, Keyu; Vanner, Michael R.; Twamley, Jason

    2014-01-01

    A quantum internet, where widely separated quantum devices are coherently connected, is a fundamental vision for local and global quantum information networks and processing. Superconducting quantum devices can now perform sophisticated quantum engineering locally on chip and a detailed method to achieve coherent optical quantum interconnection between distant superconducting devices is a vital, but highly challenging, goal. We describe a concrete opto-magneto-mechanical system that can interconvert microwave-to-optical quantum information with high fidelity. In one such node we utilise the magnetic fields generated by the supercurrent of a flux qubit to coherently modulate a mechanical oscillator that is part of a high-Q optical cavity to achieve high fidelity microwave-to-optical quantum information exchange. We analyze the transfer between two spatially distant nodes connected by an optical fibre and using currently accessible parameters we predict that the fidelity of transfer could be as high as ~80%, even with significant loss. PMID:24994063

  3. Controlling the opto-mechanics of a cantilever in an interferometer via cavity loss

    SciTech Connect

    Schmidsfeld, A. von Reichling, M.

    2015-09-21

    In a non-contact atomic force microscope, based on interferometric cantilever displacement detection, the optical return loss of the system is tunable via the distance between the fiber end and the cantilever. We utilize this for tuning the interferometer from a predominant Michelson to a predominant Fabry-Pérot characteristics and introduce the Fabry-Pérot enhancement factor as a quantitative measure for multibeam interference in the cavity. This experimentally easily accessible and adjustable parameter provides a control of the opto-mechanical interaction between the cavity light field and the cantilever. The quantitative assessment of the light pressure acting on the cantilever oscillating in the cavity via the frequency shift allows an in-situ measurement of the cantilever stiffness with remarkable precision.

  4. Temperature tracking SPICE macro-model for laser and LED driven opto-coupler assemblies

    SciTech Connect

    Deveney, M.F.

    1992-01-01

    SPICE 2G.6 compatible models were required for two opto-coupler assemblies in order to perform simulations to assess the design margins of the circuits in which they are used. Both of these assemblies are made up of discrete components, with one employing a laser diode as the light source, while the second uses a LED. Although, in use, these assemblies couple digital-like pulse trains, they are analog devices capable of operating over wider ranges of voltage than digital devices. Robust models which accurately simulate over these voltage ranges were desired. Also for ease of use, models that would track the operation of each of the assemblies over the entire specified temperature range were preferred. In addition to simulating the assembles in their intended mode of operation, it was necessary to reproduce an unwanted noise signal transfer that was observed in an early prototype circuit.

  5. Temperature tracking SPICE macro-model for laser and LED driven opto-coupler assemblies

    SciTech Connect

    Deveney, M.F.

    1992-09-01

    SPICE 2G.6 compatible models were required for two opto-coupler assemblies in order to perform simulations to assess the design margins of the circuits in which they are used. Both of these assemblies are made up of discrete components, with one employing a laser diode as the light source, while the second uses a LED. Although, in use, these assemblies couple digital-like pulse trains, they are analog devices capable of operating over wider ranges of voltage than digital devices. Robust models which accurately simulate over these voltage ranges were desired. Also for ease of use, models that would track the operation of each of the assemblies over the entire specified temperature range were preferred. In addition to simulating the assembles in their intended mode of operation, it was necessary to reproduce an unwanted noise signal transfer that was observed in an early prototype circuit.

  6. Remote Laser Processing of Composite Materials with Different Opto-Thermic Properties

    NASA Astrophysics Data System (ADS)

    Fürst, A.; Klotzbach, A.; Hühne, S.; Hauptmann, J.; Beyer, E.

    Near net shape preforms with a minimum of material consumption are required to increase the acceptance of fibre reinforced polymers in the industry, This should be accompanied with appropriate, fast and flexible processes. The 21/2 D beam deflection expands the area of possible kinds of processing strategies, wherefore the laser can be a tool for the future. The development of remote laser processing is strongly connected with the understanding of the interaction between tool and material. Within the paper investigations on opto - thermic properties of the components as a function of the wavelength of the beam source were shown. The results of the measurements are fundamental for processing composite structures made of glass- or carbon fibre and polymer matrices.

  7. Final mechanical and opto-mechanical design of the Magdalena Ridge Observatory interferometer

    NASA Astrophysics Data System (ADS)

    Santoro, Fernando G.; Olivares, Andres M.; Salcido, Chris D.; Jimenez, Stephen R.; Jurgenson, Colby A.; Sun, Xiaowei; Haniff, Christopher A.; Buscher, David F.; Creech-Eakman, Michelle J.; Selina, Robert J.; McCracken, Tyler M.; Young, John S.; Fisher, Martin; Klinglesmith, Dan; Torres, Nicolas C.; Dahl, Chuck; Shtromberg, Alisa V.; Wilson, Donald M. A.

    2012-07-01

    Most subsystems of the Magdalena Ridge Observatory Interferometer (MROI) have progressed towards final mechanical design, construction and testing since the last SPIE meeting in San Diego - CA. The first 1.4-meter telescope has successfully passed factory acceptance test, and construction of telescopes #2 and #3 has started. The beam relay system has been prototyped on site, and full construction is awaiting funding. A complete 100-meter length delay line system, which includes its laser metrology unit, has been installed and tested on site, and the first delay line trolley has successfully passed factory acceptance testing. A fully operational fringe tracker is integrated with a prototyped version of the automated alignment system for a closed looping fringe tracking experiment. In this paper, we present details of the final mechanical and opto-mechanical design for these MROI subsystems and report their status on fabrication, assembly, integration and testing.

  8. Controlling the opto-mechanics of a cantilever in an interferometer via cavity loss

    NASA Astrophysics Data System (ADS)

    von Schmidsfeld, A.; Reichling, M.

    2015-09-01

    In a non-contact atomic force microscope, based on interferometric cantilever displacement detection, the optical return loss of the system is tunable via the distance between the fiber end and the cantilever. We utilize this for tuning the interferometer from a predominant Michelson to a predominant Fabry-Pérot characteristics and introduce the Fabry-Pérot enhancement factor as a quantitative measure for multibeam interference in the cavity. This experimentally easily accessible and adjustable parameter provides a control of the opto-mechanical interaction between the cavity light field and the cantilever. The quantitative assessment of the light pressure acting on the cantilever oscillating in the cavity via the frequency shift allows an in-situ measurement of the cantilever stiffness with remarkable precision.

  9. Method and apparatus for background signal reduction in opto-acoustic absorption measurement

    NASA Technical Reports Server (NTRS)

    Rosengren, L. G. (Inventor)

    1976-01-01

    The sensitivity of an opto-acoustic absorption detector is increased to make it possible to measure trace amounts of constituent gases. A second beam radiation path is created through the sample cell identical to a first path except as to length, alternating the beam through the two paths and minimizing the detected pressure difference for the two paths while the beam wavelength is tuned away from the absorption lines of the sample. Then with the beam wavelength tuned to the absorption line of any constituent of interest, the pressure difference is a measure of trace amounts of the constituent. The same improved detector may also be used for measuring the absorption coefficient of known concentrations of absorbing gases.

  10. Localized Opto-Mechanical Control of Protein Adsorption onto Carbon Nanotubes

    PubMed Central

    O'Dell, Dakota; Serey, Xavier; Kang, Pilgyu; Erickson, David

    2014-01-01

    Chemical reactions can be described by an energy diagram along a reaction coordinate in which an activation barrier limits the rate at which reactants can be transformed into products. This reaction impedance can be overcome by reducing the magnitude of the barrier through the use of catalysis, increasing the thermal energy of the system, or through macroscopic mechanical processes. Here, we demonstrate direct molecular-scale control of a reaction through the precise application of opto-mechanical work. The method uses optical gradient forces generated in the evanescent field surrounding hybrid photonic-plasmonic structures to drive an otherwise unlikely adsorption reaction between proteins and carbon nanotubes. The adsorption of immunoglobulins on carbon nanotubes is used as a model reaction and investigated with an extended DLVO theory. The technique is also used to force a Förster resonance energy transfer between fluorophores on mismatched immunoglobulin proteins and is expected to lead to novel forms of chemical synthesis. PMID:25330911

  11. Edge pixel response studies of edgeless silicon sensor technology for pixellated imaging detectors

    NASA Astrophysics Data System (ADS)

    Maneuski, D.; Bates, R.; Blue, A.; Buttar, C.; Doonan, K.; Eklund, L.; Gimenez, E. N.; Hynds, D.; Kachkanov, S.; Kalliopuska, J.; McMullen, T.; O'Shea, V.; Tartoni, N.; Plackett, R.; Vahanen, S.; Wraight, K.

    2015-03-01

    Silicon sensor technologies with reduced dead area at the sensor's perimeter are under development at a number of institutes. Several fabrication methods for sensors which are sensitive close to the physical edge of the device are under investigation utilising techniques such as active-edges, passivated edges and current-terminating rings. Such technologies offer the goal of a seamlessly tiled detection surface with minimum dead space between the individual modules. In order to quantify the performance of different geometries and different bulk and implant types, characterisation of several sensors fabricated using active-edge technology were performed at the B16 beam line of the Diamond Light Source. The sensors were fabricated by VTT and bump-bonded to Timepix ROICs. They were 100 and 200 μ m thick sensors, with the last pixel-to-edge distance of either 50 or 100 μ m. The sensors were fabricated as either n-on-n or n-on-p type devices. Using 15 keV monochromatic X-rays with a beam spot of 2.5 μ m, the performance at the outer edge and corners pixels of the sensors was evaluated at three bias voltages. The results indicate a significant change in the charge collection properties between the edge and 5th (up to 275 μ m) from edge pixel for the 200 μ m thick n-on-n sensor. The edge pixel performance of the 100 μ m thick n-on-p sensors is affected only for the last two pixels (up to 110 μ m) subject to biasing conditions. Imaging characteristics of all sensor types investigated are stable over time and the non-uniformities can be minimised by flat-field corrections. The results from the synchrotron tests combined with lab measurements are presented along with an explanation of the observed effects.

  12. Pixel response function experimental techniques and analysis of active pixel sensor star cameras

    NASA Astrophysics Data System (ADS)

    Fumo, Patrick; Waldron, Erik; Laine, Juha-Pekka; Evans, Gary

    2015-04-01

    The pixel response function (PRF) of a pixel within a focal plane is defined as the pixel intensity with respect to the position of a point source within the pixel. One of its main applications is in the field of astrometry, which is a branch of astronomy that deals with positioning data of a celestial body for tracking movement or adjusting the attitude of a spacecraft. Complementary metal oxide semiconductor (CMOS) image sensors generally offer better radiation tolerance to protons and heavy ions than CCDs making them ideal candidates for space applications aboard satellites, but like all image sensors they are limited by their spatial frequency response, better known as the modulation transfer function. Having a well-calibrated PRF allows us to eliminate some of the uncertainty in the spatial response of the system providing better resolution and a more accurate centroid estimation. This paper describes the experimental setup for determining the PRF of a CMOS image sensor and analyzes the effect on the oversampled point spread function (PSF) of an image intensifier, as well as the effects due to the wavelength of light used as a point source. It was found that using electron bombarded active pixel sensor (EBAPS) intensification technology had a significant impact on the PRF of the camera being tested as a result of an increase in the amount of carrier diffusion between collection sites generated by the intensification process. Taking the full width at half maximum (FWHM) of the resulting data, it was found that the intensified version of a CMOS camera exhibited a PSF roughly 16.42% larger than its nonintensified counterpart.

  13. OptoDyCE: Automated system for high-throughput all-optical dynamic cardiac electrophysiology

    NASA Astrophysics Data System (ADS)

    Klimas, Aleksandra; Yu, Jinzhu; Ambrosi, Christina M.; Williams, John C.; Bien, Harold; Entcheva, Emilia

    2016-02-01

    In the last two decades, <30% of drugs withdrawals from the market were due to cardiac toxicity, where unintended interactions with ion channels disrupt the heart's normal electrical function. Consequently, all new drugs must undergo preclinical testing for cardiac liability, adding to an already expensive and lengthy process. Recognition that proarrhythmic effects often result from drug action on multiple ion channels demonstrates a need for integrative and comprehensive measurements. Additionally, patient-specific therapies relying on emerging technologies employing stem-cell derived cardiomyocytes (e.g. induced pluripotent stem-cell-derived cardiomyocytes, iPSC-CMs) require better screening methods to become practical. However, a high-throughput, cost-effective approach for cellular cardiac electrophysiology has not been feasible. Optical techniques for manipulation and recording provide a contactless means of dynamic, high-throughput testing of cells and tissues. Here, we consider the requirements for all-optical electrophysiology for drug testing, and we implement and validate OptoDyCE, a fully automated system for all-optical cardiac electrophysiology. We demonstrate the high-throughput capabilities using multicellular samples in 96-well format by combining optogenetic actuation with simultaneous fast high-resolution optical sensing of voltage or intracellular calcium. The system can also be implemented using iPSC-CMs and other cell-types by delivery of optogenetic drivers, or through the modular use of dedicated light-sensitive somatic cells in conjunction with non-modified cells. OptoDyCE provides a truly modular and dynamic screening system, capable of fully-automated acquisition of high-content information integral for improved discovery and development of new drugs and biologics, as well as providing a means of better understanding of electrical disturbances in the heart.

  14. Novel BTlGaN semiconducting materials for infrared opto-electronic devices

    NASA Astrophysics Data System (ADS)

    Assali, Abdenacer; Bouslama, M'hamed

    2017-03-01

    BTlGaN quaternary alloys are proposed as new semiconductor materials for infrared opto-electronic applications. The structural and opto-electronic properties of zinc blende BxTlyGa1-x-yN alloys lattice matched to GaN with (0 ⩽ x and y ⩽ 0.187) are studied using density functional theory (DFT) within full-potential linearized augmented plane wave (FP-LAPW) method. The calculated structural parameters such as lattice constant a0 and bulk modulus B0 are found to be in good agreement with experimental data using the new form of generalized gradient approximation (GGA-WC). The band gaps of the compounds are also found very close to the experimental results using the recently developed Tran-Blaha-modified Becke-Johnson (TB-mBJ) exchange potential. A quaternary BxTlyGa1-x-yN is expected to be lattice matched to the GaN substrate with concentrations x = 0.125 and y = 0.187 allows to produce high interface layers quality. It has been found that B incorporation into BTlGaN does not significantly affect the band gap, while the addition of dilute Tl content leads to induce a strong reduction of the band gap, which in turn increases the emission wavelengths to the infrared region. The refractivity, reflectivity and absorption coefficient of these alloys were investigated. BTlGaN/GaN is an interesting new material to be used as active layer/barriers in quantum wells suitable for realizing advanced Laser Diodes and Light-Emitting Diodes as new sources of light emitting in the infrared spectrum region.

  15. 16th Russian Youth Conference on Physics of Semiconductors and Nanostructures, Opto- and Nanoelectronics

    NASA Astrophysics Data System (ADS)

    Suris, Robert A.; Vorobjev, Leonid E.; Firsov, Dmitry A.

    2015-01-01

    The 16th Russian Youth Conference on Physics of Semiconductors and Nanostructures, Opto- and Nanoelectronics was held on November 24 - 28 at St. Petersburg Polytechnic University. The program of the Conference included semiconductor technology, heterostructures with quantum wells and quantum dots, opto- and nanoelectronic devices, and new materials. A large number of participants with about 200 attendees from many regions of Russia provided a perfect platform for the valuable discussions between students and experienced scientists. The Conference included two invited talks given by a corresponding member of RAS P.S. Kopyev ("Nitrides: the 4th Nobel Prize on semiconductor heterostructures") and Dr. A.V. Ivanchik ("XXI century is the era of precision cosmology"). Students, graduate and postgraduate students presented their results on plenary and poster sessions. The total number of accepted papers published in Russian (the official conference language) was 92. Here we publish 18 of them in English. Like previous years, the participants were involved in the competition for the best report. Certificates and cash prizes were awarded to a number of participants for the presentations selected by the Program Committee. Two special E.F. Gross Prizes were given for the best presentations in semiconductor optics. Works with potential applications were recommended for participation in the following competition for support from the Russian Foundation for Assistance to Small Innovative Enterprises in Science and Technology. The Conference was supported by the Russian Foundation for Basic Research, the "Dynasty" foundation and the innovation company "ATC - Semiconductor Devices", St. Petersburg. The official Conference website is http://www.semicond.spbstu.ru/conf2014-eng.html

  16. How big is an OMI pixel?

    NASA Astrophysics Data System (ADS)

    de Graaf, Martin; Sihler, Holger; Tilstra, Lieuwe G.; Stammes, Piet

    2016-08-01

    The Ozone Monitoring Instrument (OMI) is a push-broom imaging spectrometer, observing solar radiation backscattered by the Earth's atmosphere and surface. The incoming radiation is detected using a static imaging CCD (charge-coupled device) detector array with no moving parts, as opposed to most of the previous satellite spectrometers, which used a moving mirror to scan the Earth in the across-track direction. The field of view (FoV) of detector pixels is the solid angle from which radiation is observed, averaged over the integration time of a measurement. The OMI FoV is not quadrangular, which is common for scanning instruments, but rather super-Gaussian shaped and overlapping with the FoV of neighbouring pixels. This has consequences for pixel-area-dependent applications, like cloud fraction products, and visualisation.The shapes and sizes of OMI FoVs were determined pre-flight by theoretical and experimental tests but never verified after launch. In this paper the OMI FoV is characterised using collocated MODerate resolution Imaging Spectroradiometer (MODIS) reflectance measurements. MODIS measurements have a much higher spatial resolution than OMI measurements and spectrally overlap at 469 nm. The OMI FoV was verified by finding the highest correlation between MODIS and OMI reflectances in cloud-free scenes, assuming a 2-D super-Gaussian function with varying size and shape to represent the OMI FoV. Our results show that the OMPIXCOR product 75FoV corner coordinates are accurate as the full width at half maximum (FWHM) of a super-Gaussian FoV model when this function is assumed. The softness of the function edges, modelled by the super-Gaussian exponents, is different in both directions and is view angle dependent.The optimal overlap function between OMI and MODIS reflectances is scene dependent and highly dependent on time differences between overpasses, especially with clouds in the scene. For partially clouded scenes, the optimal overlap function was

  17. Firmware development and testing of the ATLAS Pixel Detector / IBL ROD card

    NASA Astrophysics Data System (ADS)

    Gabrielli, A.; Backhaus, M.; Balbi, G.; Bindi, M.; Chen, S. P.; Falchieri, D.; Flick, T.; Hauck, S.; Hsu, S. C.; Kretz, M.; Kugel, A.; Lama, L.; Travaglini, R.; Wensing, M.

    2015-03-01

    The ATLAS Experiment is reworking and upgrading systems during the current LHC shut down. In particular, the Pixel detector has inserted an additional inner layer called the Insertable B-Layer (IBL). The Readout-Driver card (ROD), the Back-of-Crate card (BOC), and the S-Link together form the essential frontend data path of the IBL's off-detector DAQ system. The strategy for IBL ROD firmware development was three-fold: keeping as much of the Pixel ROD datapath firmware logic as possible, employing a complete new scheme of steering and calibration firmware, and designing the overall system to prepare for a future unified code version integrating IBL and Pixel layers. Essential features such as data formatting, frontend-specific error handling, and calibration are added to the ROD data path. An IBL DAQ test bench using a realistic front-end chip model was created to serve as an initial framework for full offline electronic system simulation. In this document, major firmware achievements concerning the IBL ROD data path implementation, test on the test bench and ROD prototypes, will be reported. Recent Pixel collaboration efforts focus on finalizing hardware and firmware tests for the IBL. The plan is to approach a complete IBL DAQ hardware-software installation by the end of 2014.

  18. The link in Linking

    PubMed Central

    Caldwell, Jane C; Chiale, Pablo A; Gonzalez, Mario D; Baranchuk, Adrian

    2013-01-01

    We present 2 cases of the slow-fast form of AVNRT with initially narrow QRS complexes followed by sudden unexpected transition to persistently wide QRS complexes due to aberrant intraventricular conduction. Introduction of a properly timed extrastimulus in one case and critical oscillations in cycle length due to short-long coupling in the second case set the stage for the initial bundle branch block. However, persistence of the aberrancy pattern once the initial event abated was maintained by the "linking" phenomenon. Delayed, retrograde concealed activation from the contralateral bundle branch perpetuated the initial bundle branch block. PMID:23840106

  19. The link in Linking.

    PubMed

    Caldwell, Jane C; Chiale, Pablo A; Gonzalez, Mario D; Baranchuk, Adrian

    2013-05-01

    We present 2 cases of the slow-fast form of AVNRT with initially narrow QRS complexes followed by sudden unexpected transition to persistently wide QRS complexes due to aberrant intraventricular conduction. Introduction of a properly timed extrastimulus in one case and critical oscillations in cycle length due to short-long coupling in the second case set the stage for the initial bundle branch block. However, persistence of the aberrancy pattern once the initial event abated was maintained by the "linking" phenomenon. Delayed, retrograde concealed activation from the contralateral bundle branch perpetuated the initial bundle branch block.

  20. Pixel-level plasmonic microcavity infrared photodetector

    NASA Astrophysics Data System (ADS)

    Jing, You Liang; Li, Zhi Feng; Li, Qian; Chen, Xiao Shuang; Chen, Ping Ping; Wang, Han; Li, Meng Yao; Li, Ning; Lu, Wei

    2016-05-01

    Recently, plasmonics has been central to the manipulation of photons on the subwavelength scale, and superior infrared imagers have opened novel applications in many fields. Here, we demonstrate the first pixel-level plasmonic microcavity infrared photodetector with a single quantum well integrated between metal patches and a reflection layer. Greater than one order of magnitude enhancement of the peak responsivity has been observed. The significant improvement originates from the highly confined optical mode in the cavity, leading to a strong coupling between photons and the quantum well, resulting in the enhanced photo-electric conversion process. Such strong coupling from the localized surface plasmon mode inside the cavity is independent of incident angles, offering a unique solution to high-performance focal plane array devices. This demonstration paves the way for important infrared optoelectronic devices for sensing and imaging.

  1. Pixel-level plasmonic microcavity infrared photodetector

    PubMed Central

    Jing, You Liang; Li, Zhi Feng; Li, Qian; Chen, Xiao Shuang; Chen, Ping Ping; Wang, Han; Li, Meng Yao; Li, Ning; Lu, Wei

    2016-01-01

    Recently, plasmonics has been central to the manipulation of photons on the subwavelength scale, and superior infrared imagers have opened novel applications in many fields. Here, we demonstrate the first pixel-level plasmonic microcavity infrared photodetector with a single quantum well integrated between metal patches and a reflection layer. Greater than one order of magnitude enhancement of the peak responsivity has been observed. The significant improvement originates from the highly confined optical mode in the cavity, leading to a strong coupling between photons and the quantum well, resulting in the enhanced photo-electric conversion process. Such strong coupling from the localized surface plasmon mode inside the cavity is independent of incident angles, offering a unique solution to high-performance focal plane array devices. This demonstration paves the way for important infrared optoelectronic devices for sensing and imaging. PMID:27181111

  2. Silicon buried channels for pixel detector cooling

    NASA Astrophysics Data System (ADS)

    Boscardin, M.; Conci, P.; Crivellari, M.; Ronchin, S.; Bettarini, S.; Bosi, F.

    2013-08-01

    The support and cooling structures add important contributions to the thickness, in radiation length, of vertex detectors. In order to minimize the material budget of pixel sensors, we developed a new approach to integrate the cooling into the silicon devices. The microchannels are formed in silicon using isotropic SF6 plasma etching in a DRIE (deep reactive ion etcher) equipment. Due to their peculiar profiles, the channels can be sealed by a layer of a PECVD silicon oxide. We have realized on a silicon wafer microchannels with different geometries and hydraulic diameters. We describe the main fabrication steps of microchannels with focus on the channel definition. The experimental results are reported on the thermal characterization of several prototypes, using a mixture of glycol and water as a liquid coolant. The prototypes have shown high cooling efficiency and high-pressure breaking strength.

  3. Operational experience with the ALICE pixel detector

    NASA Astrophysics Data System (ADS)

    Mastroserio, A.

    2017-01-01

    The Silicon Pixel Detector (SPD) constitutes the two innermost layers of the Inner Tracking System of the ALICE experiment and it is the closest detector to the interaction point. As a vertex detector, it has the unique feature of generating a trigger signal that contributes to the L0 trigger of the ALICE experiment. The SPD started collecting data since the very first pp collisions at LHC in 2009 and since then it has taken part in all pp, Pb-Pb and p-Pb data taking campaigns. This contribution will present the main features of the SPD, the detector performance and the operational experience, including calibration and optimization activities from Run 1 to Run 2.

  4. Research of IRFPAs' reliability evaluation by bad pixel

    NASA Astrophysics Data System (ADS)

    Hao, Lichao; Huang, Aibo; Lai, Canxiong; Chen, Xing; Hao, Mingming; Chen, Honglei; Lu, Guoguang; Huang, Yun; En, Yunfei

    2015-10-01

    Reliability is an important index to ensure the application of infrared focal plane arrays (IRFPAs) in complex environment, and it becomes a major bottleneck problem of IRFPAs' development. Because of the characteristics such as type, nature, quantity, location and distribution et al, bad pixel which contains initial bad pixel and used bad pixel has outstanding advantage for failure analysis and reliability evaluation of IRFPAs. In this paper, the structure of IRPFAs has been introduced in detail, and the damage mechanisms of used bad pixel also have been analyzed deeply. At the same time, the feasibility to study IRPFAs' damage stress, failure position, damage mechanism has been discussed all around. The research of bad pixel can be used to optimize the structure and process, meanwhile it also can improve the accuracy of bad pixel identification and replacements.

  5. RF Photonic Technology in Optical Fiber Links

    NASA Astrophysics Data System (ADS)

    Chang, William S. C.

    2007-06-01

    List of contributors; Introduction and preface; 1. Figures of merit and performance analysis of photonic microwave links Charles Cox and William S. C. Chang; 2. RF subcarrier links in local access networks Xiaolin Lu; 3. Analog modulation of semiconductor lasers Joachim Piprek and John E. Bowers; 4. LiNbO3 external modulators and their use in high performance analog links Gary E. Betts; 5. Broadband traveling wave modulators in LiNbO3 Marta M. Howerton and William K. Burns; 6. Multiple quantum well electroabsorption modulators for RF photonic links William S. C. Chang; 7. Polymer modulators for RF photonics Timothy Van Eck; 8. Photodiodes for high performance analog links P. K. L. Yu and Ming C. Wu; 9. Opto-electronic oscillators X. Steve Yao; 10. Photonic link techniques for microwave frequency conversion Stephen A. Pappert, Roger Helkey and Ronald T. Logan Jr; 11. Antenna-coupled millimeter-wave electro-optical modulators William B. Bridges; 12. System design and performance of wideband photonic phased array antennas Greg L. Tangonan, Willie Ng, Daniel Yap and Ron Stephens; Acknowledgements; References; Index.

  6. Fast Pixel Buffer For Processing With Lookup Tables

    NASA Technical Reports Server (NTRS)

    Fisher, Timothy E.

    1992-01-01

    Proposed scheme for buffering data on intensities of picture elements (pixels) of image increases rate or processing beyond that attainable when data read, one pixel at time, from main image memory. Scheme applied in design of specialized image-processing circuitry. Intended to optimize performance of processor in which electronic equivalent of address-lookup table used to address those pixels in main image memory required for processing.

  7. Mapping Capacitive Coupling Among Pixels in a Sensor Array

    NASA Technical Reports Server (NTRS)

    Seshadri, Suresh; Cole, David M.; Smith, Roger M.

    2010-01-01

    An improved method of mapping the capacitive contribution to cross-talk among pixels in an imaging array of sensors (typically, an imaging photodetector array) has been devised for use in calibrating and/or characterizing such an array. The method involves a sequence of resets of subarrays of pixels to specified voltages and measurement of the voltage responses of neighboring non-reset pixels.

  8. Steganography on quantum pixel images using Shannon entropy

    NASA Astrophysics Data System (ADS)

    Laurel, Carlos Ortega; Dong, Shi-Hai; Cruz-Irisson, M.

    2016-07-01

    This paper presents a steganographical algorithm based on least significant bit (LSB) from the most significant bit information (MSBI) and the equivalence of a bit pixel image to a quantum pixel image, which permits to make the information communicate secretly onto quantum pixel images for its secure transmission through insecure channels. This algorithm offers higher security since it exploits the Shannon entropy for an image.

  9. CMOS monolithic pixel sensors research and development at LBNL

    NASA Astrophysics Data System (ADS)

    Contarato, D.; Bussat, J.-M.; Denes, P.; Greiner, L.; Kim, T.; Stezelberger, T.; Wieman, H.; Battaglia, M.; Hooberman, B.; Tompkins, L.

    2007-12-01

    This paper summarizes the recent progress in the design and characterization of CMOS pixel sensors at LBNL. Results of lab tests, beam tests and radiation hardness tests carried out at LBNL on a test structure with pixels of various sizes are reported. The first results of the characterization of back-thinned CMOS pixel sensors are also reported, and future plans and activities are discussed.

  10. Hit efficiency study of CMS prototype forward pixel detectors

    SciTech Connect

    Kim, Dongwook; /Johns Hopkins U.

    2006-01-01

    In this paper the author describes the measurement of the hit efficiency of a prototype pixel device for the CMS forward pixel detector. These pixel detectors were FM type sensors with PSI46V1 chip readout. The data were taken with the 120 GeV proton beam at Fermilab during the period of December 2004 to February 2005. The detectors proved to be highly efficient (99.27 {+-} 0.02%). The inefficiency was primarily located near the corners of the individual pixels.

  11. Evaluation of a single-pixel one-transistor active pixel sensor for fingerprint imaging

    NASA Astrophysics Data System (ADS)

    Xu, Man; Ou, Hai; Chen, Jun; Wang, Kai

    2015-08-01

    Since it first appeared in iPhone 5S in 2013, fingerprint identification (ID) has rapidly gained popularity among consumers. Current fingerprint-enabled smartphones unanimously consists of a discrete sensor to perform fingerprint ID. This architecture not only incurs higher material and manufacturing cost, but also provides only static identification and limited authentication. Hence as the demand for a thinner, lighter, and more secure handset grows, we propose a novel pixel architecture that is a photosensitive device embedded in a display pixel and detects the reflected light from the finger touch for high resolution, high fidelity and dynamic biometrics. To this purpose, an amorphous silicon (a-Si:H) dual-gate photo TFT working in both fingerprint-imaging mode and display-driving mode will be developed.

  12. Reduction of ring artifacts in CBCT: Detection and correction of pixel gain variations in flat panel detectors

    SciTech Connect

    Altunbas, Cem; Lai, Chao-Jen; Zhong, Yuncheng; Shaw, Chris C.

    2014-09-15

    Purpose: In using flat panel detectors (FPD) for cone beam computed tomography (CBCT), pixel gain variations may lead to structured nonuniformities in projections and ring artifacts in CBCT images. Such gain variations can be caused by change in detector entrance exposure levels or beam hardening, and they are not accounted by conventional flat field correction methods. In this work, the authors presented a method to identify isolated pixel clusters that exhibit gain variations and proposed a pixel gain correction (PGC) method to suppress both beam hardening and exposure level dependent gain variations. Methods: To modulate both beam spectrum and entrance exposure, flood field FPD projections were acquired using beam filters with varying thicknesses. “Ideal” pixel values were estimated by performing polynomial fits in both raw and flat field corrected projections. Residuals were calculated by taking the difference between measured and ideal pixel values to identify clustered image and FPD artifacts in flat field corrected and raw images, respectively. To correct clustered image artifacts, the ratio of ideal to measured pixel values in filtered images were utilized as pixel-specific gain correction factors, referred as PGC method, and they were tabulated as a function of pixel value in a look-up table. Results: 0.035% of detector pixels lead to clustered image artifacts in flat field corrected projections, where 80% of these pixels were traced back and linked to artifacts in the FPD. The performance of PGC method was tested in variety of imaging conditions and phantoms. The PGC method reduced clustered image artifacts and fixed pattern noise in projections, and ring artifacts in CBCT images. Conclusions: Clustered projection image artifacts that lead to ring artifacts in CBCT can be better identified with our artifact detection approach. When compared to the conventional flat field correction method, the proposed PGC method enables characterization of nonlinear

  13. How Many Pixels Does It Take to Make a Good 4"×6" Print? Pixel Count Wars Revisited

    NASA Astrophysics Data System (ADS)

    Kriss, Michael A.

    Digital still cameras emerged following the introduction of the Sony Mavica analog prototype camera in 1981. These early cameras produced poor image quality and did not challenge film cameras for overall quality. By 1995 digital still cameras in expensive SLR formats had 6 mega-pixels and produced high quality images (with significant image processing). In 2005 significant improvement in image quality was apparent and lower prices for digital still cameras (DSCs) started a rapid decline in film usage and film camera sells. By 2010 film usage was mostly limited to professionals and the motion picture industry. The rise of DSCs was marked by a “pixel war” where the driving feature of the cameras was the pixel count where even moderate cost, ˜120, DSCs would have 14 mega-pixels. The improvement of CMOS technology pushed this trend of lower prices and higher pixel counts. Only the single lens reflex cameras had large sensors and large pixels. The drive for smaller pixels hurt the quality aspects of the final image (sharpness, noise, speed, and exposure latitude). Only today are camera manufactures starting to reverse their course and producing DSCs with larger sensors and pixels. This paper will explore why larger pixels and sensors are key to the future of DSCs.

  14. Design and characterization of high precision in-pixel discriminators for rolling shutter CMOS pixel sensors with full CMOS capability

    NASA Astrophysics Data System (ADS)

    Fu, Y.; Hu-Guo, C.; Dorokhov, A.; Pham, H.; Hu, Y.

    2013-07-01

    In order to exploit the ability to integrate a charge collecting electrode with analog and digital processing circuitry down to the pixel level, a new type of CMOS pixel sensors with full CMOS capability is presented in this paper. The pixel array is read out based on a column-parallel read-out architecture, where each pixel incorporates a diode, a preamplifier with a double sampling circuitry and a discriminator to completely eliminate analog read-out bottlenecks. The sensor featuring a pixel array of 8 rows and 32 columns with a pixel pitch of 80 μm×16 μm was fabricated in a 0.18 μm CMOS process. The behavior of each pixel-level discriminator isolated from the diode and the preamplifier was studied. The experimental results indicate that all in-pixel discriminators which are fully operational can provide significant improvements in the read-out speed and the power consumption of CMOS pixel sensors.

  15. High-dynamic-range pixel architectures for diagnostic medical imaging

    NASA Astrophysics Data System (ADS)

    Karim, Karim S.; Yin, Sherman; Nathan, Arokia; Rowlands, John A.

    2004-05-01

    One approach to increase pixel signal-to-noise ratio (SNR) in low noise digital fluoroscopy is to employ in-situ pixel amplification via current-mediated active pixel sensors (C-APS). Experiments reveal a reduction in readout noise and indicate that an a-Si C-APS, coupled together with an established X-ray detection technology such as amorphous selenium (a-Se), can meet the stringent requirements (of < 1000 noise electrons) for digital X-ray fluoroscopy. A challenge with the C-APS circuit is the presence of a small-signal input linearity constraint. While using such a pixel amplifier for real-time fluoroscopy (where the exposure level is small) is feasible, the voltage change at the amplifier input is much higher in chest radiography or mammography due to the larger X-ray exposure levels. The larger input voltage causes the C-APS output to be non-linear thus reducing the pixel dynamic range. In addition, the resulting larger pixel output current causes the external column amplifier to saturate further reducing the pixel dynamic range. In this research, we investigate two alternate amplified pixel architectures that exhibit higher dynamic range. The test pixels are designed and simulated using an a-Si TFT model implemented in Verilog-A and results indicate a linear performance, high dynamic range, and a programmable circuit gain via choice of supply voltage and sampling time. These high dynamic range pixel architectures have the potential to enable a large area, active matrix flat panel imager (AMFPI) to switch instantly between low exposure, fluoroscopic imaging and higher exposure radiographic imaging modes. Lastly, the high dynamic range pixel circuits are suitable for integration with on-panel multiplexers for both gate and data lines, which can further reduce circuit complexity.

  16. A novel reconfigurable optical interconnect architecture using an Opto-VLSI processor and a 4-f imaging system.

    PubMed

    Shen, Mingya; Xiao, Feng; Alameh, Kamal

    2009-12-07

    A novel reconfigurable optical interconnect architecture for on-board high-speed data transmission is proposed and experimentally demonstrated. The interconnect architecture is based on the use of an Opto-VLSI processor in conjunction with a 4-f imaging system to achieve reconfigurable chip-to-chip or board-to-board data communications. By reconfiguring the phase hologram of an Opto-VLSI processor, optical data generated by a vertical Cavity Surface Emitting Laser (VCSEL) associated to a chip (or a board) is arbitrarily steered to the photodetector associated to another chip (or another board). Experimental results show that the optical interconnect losses range from 5.8dB to 9.6dB, and that the maximum crosstalk level is below -36dB. The proposed architecture is tested for high-speed data transmission, and measured eye diagrams display good eye opening for data rate of up to 10Gb/s.

  17. Opto-Mechanics of the Constellation-X SXT Mirrors: Challenges in Mounting and Assembling the Mirror Segments

    NASA Technical Reports Server (NTRS)

    Chan, Kai-Wing; Zhang, WIlliam W.; Saha, Timo; Lehan, John P.; Mazzarella, James; Lozipone, Lawrence; Hong, Melinda; Byron, Glenn

    2008-01-01

    The Constellation-X Spectroscopy X-Ray Telescopes consists of segmented glass mirrors with an axial length of 200 mm, a width of up to 400 mm, and a thickness of 0.4 mm. To meet the requirement of less than 15 arc-second half-power diameter with the small thickness and relatively large size is a tremendous challenge in opto-mechanics. How shall we limit distortion of the mirrors due to gravity in ground tests, that arises from thermal stress, and that occurs in the process of mounting, affixing and assembling of these mirrors? In this paper, we will describe our current opto-mechanical approach to these problems. We will discuss, in particular, the approach and experiment where the mirrors are mounted vertically by first suspending it at two points.

  18. Introduction of a new opto-electrical phase-locked loop in CMOS technology: the PMD-PLL

    NASA Astrophysics Data System (ADS)

    Ringbeck, Thorsten; Schwarte, Rudolf; Buxbaum, Bernd

    1999-12-01

    The huge and increasing need of information in the industrial world demands an enormous potential of bandwidth in telecommunication systems. Optical communication provides all participants with the whole spectrum of digital services like videophone, cable TV, video conferencing and online services. Especially fast and low cost opto-electrical receivers are badly needed in order to expand fiber networks to every home (FTTH--fiber to the home or FTTD--fiber to the desk, respectively). This paper proposes a new receiver structure which is designed to receiver optical data which are encoded by code division multiple access techniques (CDMA). For data recovery in such CDMA networks phase locked loops (PLL) are needed, which synchronize the local oscillator with the incoming clock. In optical code division multiple access networks these PLLs could be realized either with an electrical PLL after opto-electrical converting or directly in the optical path with a pure optical PLL.

  19. Direct opto-acoustic in vitro measurement of the spatial distribution of laser radiation in biological media

    SciTech Connect

    Pelivanov, Ivan M; Belov, Sergej A; Solomatin, Vladimir S; Khokhlova, Tanya D; Karabutov, Aleksander A

    2006-12-31

    The problem of opto-acoustic (AO) diagnostics of light scattering and absorption in biological media is considered. The objects under study were milk, bovine and porcine liver, and bovine muscle tissue. The forward and backward schemes for recording acoustic signals were used in experiments. The spatial distribution of the light intensity was measured for each biological medium from the temporal profile of the excited OA pulse and the absorption coefficient and reduced scattering coefficient were determined. Opto-acoustic signals were excited by a 1064-nm pulsed Nd:YAG laser and a tunable Ti:sapphire laser at 779 nm. It is shown that the proposed method can be used for obtaining a priori information on a biological medium in problems of optical and AO tomography. (special issue devoted to multiple radiation scattering in random media)

  20. Link direction for link prediction

    NASA Astrophysics Data System (ADS)

    Shang, Ke-ke; Small, Michael; Yan, Wei-sheng

    2017-03-01

    Almost all previous studies on link prediction have focused on using the properties of the network to predict the existence of links between pairs of nodes. Unfortunately, previous methods rarely consider the role of link direction for link prediction. In fact, many real-world complex networks are directed and ignoring the link direction will mean overlooking important information. In this study, we propose a phase-dynamic algorithm of the directed network nodes to analyse the role of link directions and demonstrate that the bi-directional links and the one-directional links have different roles in link prediction and network structure formation. From this, we propose new directional prediction methods and use six real networks to test our algorithms. In real networks, we find that compared to a pair of nodes which are connected by a one-directional link, a pair of nodes which are connected by a bi-directional link always have higher probabilities to connect to the common neighbours with only bi-directional links (or conversely by one-directional links). We suggest that, in the real networks, the bi-directional links will generally be more informative for link prediction and network structure formation. In addition, we propose a new directional randomized algorithm to demonstrate that the direction of the links plays a significant role in link prediction and network structure formation.

  1. Electro-opto-mechanical radio-frequency oscillator driven by guided acoustic waves in standard single-mode fiber

    NASA Astrophysics Data System (ADS)

    London, Yosef; Diamandi, Hilel Hagai; Zadok, Avi

    2017-04-01

    An opto-electronic radio-frequency oscillator that is based on forward scattering by the guided acoustic modes of a standard single-mode optical fiber is proposed and demonstrated. An optical pump wave is used to stimulate narrowband, resonant guided acoustic modes, which introduce phase modulation to a co-propagating optical probe wave. The phase modulation is converted to an intensity signal at the output of a Sagnac interferometer loop. The intensity waveform is detected, amplified, and driven back to modulate the optical pump. Oscillations are achieved at a frequency of 319 MHz, which matches the resonance of the acoustic mode that provides the largest phase modulation of the probe wave. Oscillations at the frequencies of competing acoustic modes are suppressed by at least 40 dB. The linewidth of the acoustic resonance is sufficiently narrow to provide oscillations at a single longitudinal mode of the hybrid cavity. Competing longitudinal modes are suppressed by at least 38 dB as well. Unlike other opto-electronic oscillators, no radio-frequency filtering is required within the hybrid cavity. The frequency of oscillations is entirely determined by the fiber opto-mechanics.

  2. Novel integrated CMOS pixel structures for vertex detectors

    SciTech Connect

    Kleinfelder, Stuart; Bieser, Fred; Chen, Yandong; Gareus, Robin; Matis, Howard S.; Oldenburg, Markus; Retiere, Fabrice; Ritter, Hans Georg; Wieman, Howard H.; Yamamoto, Eugene

    2003-10-29

    Novel CMOS active pixel structures for vertex detector applications have been designed and tested. The overriding goal of this work is to increase the signal to noise ratio of the sensors and readout circuits. A large-area native epitaxial silicon photogate was designed with the aim of increasing the charge collected per struck pixel and to reduce charge diffusion to neighboring pixels. The photogate then transfers the charge to a low capacitance readout node to maintain a high charge to voltage conversion gain. Two techniques for noise reduction are also presented. The first is a per-pixel kT/C noise reduction circuit that produces results similar to traditional correlated double sampling (CDS). It has the advantage of requiring only one read, as compared to two for CDS, and no external storage or subtraction is needed. The technique reduced input-referred temporal noise by a factor of 2.5, to 12.8 e{sup -}. Finally, a column-level active reset technique is explored that suppresses kT/C noise during pixel reset. In tests, noise was reduced by a factor of 7.6 times, to an estimated 5.1 e{sup -} input-referred noise. The technique also dramatically reduces fixed pattern (pedestal) noise, by up to a factor of 21 in our tests. The latter feature may possibly reduce pixel-by-pixel pedestal differences to levels low enough to permit sparse data scan without per-pixel offset corrections.

  3. Method for hyperspectral imagery exploitation and pixel spectral unmixing

    NASA Technical Reports Server (NTRS)

    Lin, Ching-Fang (Inventor)

    2003-01-01

    An efficiently hybrid approach to exploit hyperspectral imagery and unmix spectral pixels. This hybrid approach uses a genetic algorithm to solve the abundance vector for the first pixel of a hyperspectral image cube. This abundance vector is used as initial state in a robust filter to derive the abundance estimate for the next pixel. By using Kalman filter, the abundance estimate for a pixel can be obtained in one iteration procedure which is much fast than genetic algorithm. The output of the robust filter is fed to genetic algorithm again to derive accurate abundance estimate for the current pixel. The using of robust filter solution as starting point of the genetic algorithm speeds up the evolution of the genetic algorithm. After obtaining the accurate abundance estimate, the procedure goes to next pixel, and uses the output of genetic algorithm as the previous state estimate to derive abundance estimate for this pixel using robust filter. And again use the genetic algorithm to derive accurate abundance estimate efficiently based on the robust filter solution. This iteration continues until pixels in a hyperspectral image cube end.

  4. Hybrid Pixel Detectors for gamma/X-ray imaging

    NASA Astrophysics Data System (ADS)

    Hatzistratis, D.; Theodoratos, G.; Zografos, V.; Kazas, I.; Loukas, D.; Lambropoulos, C. P.

    2015-09-01

    Hybrid pixel detectors are made by direct converting high-Z semi-insulating single crystalline material coupled to complementary-metal-oxide semiconductor (CMOS) readout electronics. They are attractive because direct conversion exterminates all the problems of spatial localization related to light diffusion, energy resolution, is far superior from the combination of scintillation crystals and photomultipliers and lithography can be used to pattern electrodes with very fine pitch. We are developing 2-D pixel CMOS ASICs, connect them to pixilated CdTe crystals with the flip chip and bump bonding method and characterize the hybrids. We have designed a series of circuits, whose latest member consists of a 50×25 pixel array with 400um pitch and an embedded controller. In every pixel a full spectroscopic channel with time tagging information has been implemented. The detectors are targeting Compton scatter imaging and they can be used for coded aperture imaging too. Hybridization using CMOS can overcome the limit put on pixel circuit complexity by the use of thin film transistors (TFT) in large flat panels. Hybrid active pixel sensors are used in dental imaging and other applications (e.g. industrial CT etc.). Thus X-ray imaging can benefit from the work done on dynamic range enhancement methods developed initially for visible and infrared CMOS pixel sensors. A 2-D CMOS ASIC with 100um pixel pitch to demonstrate the feasibility of such methods in the context of X-ray imaging has been designed.

  5. CMOS Active-Pixel Image Sensor With Simple Floating Gates

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R.; Nakamura, Junichi; Kemeny, Sabrina E.

    1996-01-01

    Experimental complementary metal-oxide/semiconductor (CMOS) active-pixel image sensor integrated circuit features simple floating-gate structure, with metal-oxide/semiconductor field-effect transistor (MOSFET) as active circuit element in each pixel. Provides flexibility of readout modes, no kTC noise, and relatively simple structure suitable for high-density arrays. Features desirable for "smart sensor" applications.

  6. SPIDR, a general-purpose readout system for pixel ASICs

    NASA Astrophysics Data System (ADS)

    van der Heijden, B.; Visser, J.; van Beuzekom, M.; Boterenbrood, H.; Kulis, S.; Munneke, B.; Schreuder, F.

    2017-02-01

    The SPIDR (Speedy PIxel Detector Readout) system is a flexible general-purpose readout platform that can be easily adapted to test and characterize new and existing detector readout ASICs. It is originally designed for the readout of pixel ASICs from the Medipix/Timepix family, but other types of ASICs or front-end circuits can be read out as well. The SPIDR system consists of an FPGA board with memory and various communication interfaces, FPGA firmware, CPU subsystem and an API library on the PC . The FPGA firmware can be adapted to read out other ASICs by re-using IP blocks. The available IP blocks include a UDP packet builder, 1 and 10 Gigabit Ethernet MAC's and a "soft core" CPU . Currently the firmware is targeted at the Xilinx VC707 development board and at a custom board called Compact-SPIDR . The firmware can easily be ported to other Xilinx 7 series and ultra scale FPGAs. The gap between an ASIC and the data acquisition back-end is bridged by the SPIDR system. Using the high pin count VITA 57 FPGA Mezzanine Card (FMC) connector only a simple chip carrier PCB is required. A 1 and a 10 Gigabit Ethernet interface handle the connection to the back-end. These can be used simultaneously for high-speed data and configuration over separate channels. In addition to the FMC connector, configurable inputs and outputs are available for synchronization with other detectors. A high resolution (≈ 27 ps bin size) Time to Digital converter is provided for time stamping events in the detector. The SPIDR system is frequently used as readout for the Medipix3 and Timepix3 ASICs. Using the 10 Gigabit Ethernet interface it is possible to read out a single chip at full bandwidth or up to 12 chips at a reduced rate. Another recent application is the test-bed for the VeloPix ASIC, which is developed for the Vertex Detector of the LHCb experiment. In this case the SPIDR system processes the 20 Gbps scrambled data stream from the VeloPix and distributes it over four 10 Gigabit

  7. Singlet mega-pixel resolution lens

    NASA Astrophysics Data System (ADS)

    Lin, Chen-Hung; Lin, Hoang Yan; Chang, Horng

    2008-03-01

    There always exist some new challenges for lens designers to keep their old-line technology update. To minimize lens volume is one of the most notified examples. In this paper we designed a single thick lens, constructed by using one oblique (reflective) surface, apart from two conventional refractive surfaces, to bend the optical path of the optical system to achieve this goal. Detail design procedure, including system layout and lens performance diagrams, will be presented. Following the first order layout, we applied aspherical form to the two refractive surfaces in order to correct the spherical aberration up to an acceptable condition. Then, the reduced aberrations such as coma, astigmatism, field curvature and distortion can easily be corrected with some calculations related to spherical aberration as shown in the publication of H. H. Hopkins (1950). Plastic material is used in the design, because the aspherical surfaces can then be manufactured in a more cost effective way. The final specification of the design is: EFL is 4.6 mm, the F number is 2.8, the over all thickness of lens is 3.6 mm, its MTF is 0.3 at 227 lp/mm in center field and chief ray angle is less than 15 degrees. Lens data as well as optical performance curves are also presented in the paper. In conclusion we have successfully finished a mega-pixel resolution lens design and its overall thickness is compatible with the state of the art.

  8. Hyperspectral Anomaly Detection by Graph Pixel Selection.

    PubMed

    Yuan, Yuan; Ma, Dandan; Wang, Qi

    2016-12-01

    Hyperspectral anomaly detection (AD) is an important problem in remote sensing field. It can make full use of the spectral differences to discover certain potential interesting regions without any target priors. Traditional Mahalanobis-distance-based anomaly detectors assume the background spectrum distribution conforms to a Gaussian distribution. However, this and other similar distributions may not be satisfied for the real hyperspectral images. Moreover, the background statistics are susceptible to contamination of anomaly targets which will lead to a high false-positive rate. To address these intrinsic problems, this paper proposes a novel AD method based on the graph theory. We first construct a vertex- and edge-weighted graph and then utilize a pixel selection process to locate the anomaly targets. Two contributions are claimed in this paper: 1) no background distributions are required which makes the method more adaptive and 2) both the vertex and edge weights are considered which enables a more accurate detection performance and better robustness to noise. Intensive experiments on the simulated and real hyperspectral images demonstrate that the proposed method outperforms other benchmark competitors. In addition, the robustness of the proposed method has been validated by using various window sizes. This experimental result also demonstrates the valuable characteristic of less computational complexity and less parameter tuning for real applications.

  9. Silicon micro sensors as integrated readout platform for colorimetric and fluorescence based opto-chemical transducers

    NASA Astrophysics Data System (ADS)

    Will, Matthias; Martan, Tomas; Brodersen, Olaf

    2011-09-01

    Opto-chemical transducer almost offers unlimited possibilities for detection of physical quantities. New technologies and research show a steady increasing of publications in the area of sensoric principles. For transfer to real world applications the optical response has to be converted into an electrical signal. An exceptional opto chemical transducer loses the attraction if complex and expensive instruments for analysis are requires. Therefore, the readout system must be very compact and producible for low cost. In this presentation, the technology platform as a solution for these problems will be presented. We combine micro structuring of silicon, photodiode fabrication, chip in chip mounting and novel assembly technologies for creation of a flexible sensor platform. This flexible combination of technologies allows fabricating a family of planar optical remission sensors. With variation of design and modifications, we are able to detect colorimetric, fluorescent properties of an sensitive layer attached on the sensor surface. In our sensor with typical size of 6mm x 6mm x 1mm different emitting sources based on LED's or laser diodes, multiple detection cannels for the remitted light and also measurement of temperature are included. Based on these sensors we proof the concept by demonstrating sensors for oxygen, carbon dioxide and ammonia based on colorimetric and fluorescent changes in the transducer layer. In both configurations, LED's irradiated the sensitive polymer layer through a transparent substrate. The absorption or fluorescence properties of dyed polymer are changed by the chemical reaction and light response is detected by PIN diodes. The signal shift is analyzed by using a computer controlled evaluation board of own construction. Accuracy and reliability of the remission sensor system were verified and the whole sensor system was experimentally tested in the range of concentrations from 50 ppm up to 100 000 ppm for CO2 and O2 Furthermore, we develop

  10. Silicon micro sensors as integrated readout platform for colorimetric and fluorescence based opto-chemical transducers

    NASA Astrophysics Data System (ADS)

    Will, Matthias; Martan, Tomas; Brodersen, Olaf

    2012-02-01

    Opto-chemical transducer almost offers unlimited possibilities for detection of physical quantities. New technologies and research show a steady increasing of publications in the area of sensoric principles. For transfer to real world applications the optical response has to be converted into an electrical signal. An exceptional opto chemical transducer loses the attraction if complex and expensive instruments for analysis are requires. Therefore, the readout system must be very compact and producible for low cost. In this presentation, the technology platform as a solution for these problems will be presented. We combine micro structuring of silicon, photodiode fabrication, chip in chip mounting and novel assembly technologies for creation of a flexible sensor platform. This flexible combination of technologies allows fabricating a family of planar optical remission sensors. With variation of design and modifications, we are able to detect colorimetric, fluorescent properties of an sensitive layer attached on the sensor surface. In our sensor with typical size of 6mm x 6mm x 1mm different emitting sources based on LED's or laser diodes, multiple detection cannels for the remitted light and also measurement of temperature are included. Based on these sensors we proof the concept by demonstrating sensors for oxygen, carbon dioxide and ammonia based on colorimetric and fluorescent changes in the transducer layer. In both configurations, LED's irradiated the sensitive polymer layer through a transparent substrate. The absorption or fluorescence properties of dyed polymer are changed by the chemical reaction and light response is detected by PIN diodes. The signal shift is analyzed by using a computer controlled evaluation board of own construction. Accuracy and reliability of the remission sensor system were verified and the whole sensor system was experimentally tested in the range of concentrations from 50 ppm up to 100 000 ppm for CO2 and O2 Furthermore, we develop

  11. Design strategies of opto-mechanical micro oscillators for the detection of the ponderomotive squeezing

    NASA Astrophysics Data System (ADS)

    Borrielli, A.; Bonaldi, M.; Serra, E.; Bagolini, A.; Boscardin, M.; Cataliotti, F. S.; Marin, F.; Marino, F.; Pontin, A.; Prodi, G. A.

    2013-05-01

    The interaction of the radiation pressure with micro-mechanical oscillators is earning a growing interest for its wide-range applications (including high sensitivity measurements of force and position) and for fundamental research (entanglement, ponderomotive squeezing, quantum non-demolition measurements). In this contribution we describe the fabrication of a family of opto-mechanical devices specifically designed to ease the detection of ponderomotive squeezing and of entanglement between macroscopic objects and light. These phenomena are not easily observed, due to the overwhelming effects of classical noise sources of thermal origin with respect to the weak quantum fluctuations of the radiation pressure. Therefore, a low thermal noise background is required, together with a weak interaction between the micro-mirror and this background (i.e. high mechanical quality factors). The device should also be capable to manage a relatively large amount of dissipated power at cryogenic temperatures, as the use of a laser with power up to a ten of mW can be useful to enhance radiation pressure effects. In the development of our opto-mechanical devices, we are exploring an approach focused on relatively thick silicon oscillators with high reflectivity coating. The relatively high mass is compensated by the capability to manage high power at low temperatures, owing to a favourable geometric factor (thicker connectors) and the excellent thermal conductivity of silicon crystals at cryogenic temperature. We have measured at cryogenic temperatures mechanical quality factors up to 105 in a micro-oscillator designed to reduce as much as possible the strain in the coating layer and the consequent energy dissipation. This design improves an approach applied in micro-mirror and micro-cantilevers, where the coated surface is reduced as much as possible to improve the quality factor. The deposition of the highly reflective coating layer has been carefully integrated in the

  12. Dispositifs opto-électropiques à commande par coordonnées

    NASA Astrophysics Data System (ADS)

    Smovge, A. K.

    1994-06-01

    The approach has been explained theoretically and experimentally considering analog coordinate-controlled optoelectronic devices as an alternative to custom potentiometers and variable resistors, whose potentially unreliable element, a wiping electromechanical contact, is eliminated through the use of an optoelectronic conversion principle. The new designs have been proposed and requirements for discrete-continuous photoresistor structure have been determined by using both simple numeric and analytical models for a realization of the coordinate dependence of the output voltage and internal resistance with predetermined accuracy. The new type of optoelectronic coordinate-controlled delay line of millisecond-range pulsed signals have been proposed as well as the design of two-dimensional sensor of displacements. The new method for upgradding the noise immunity, based on the use of the photoconductivity response time dependence from the illuminance have been proposed. Une direction de recherches a été justifiée théoriquement et expérimentalement. Cette étude considère les dipositifs opto-électroniques à commande par coordonnées comme une alternative aux potentiomètres classiques dont l'élément défaillant éventuel, à savoir le contact électrique mobile de frottement, est supprimé par l'emploi d'une méthode de conversion optoélectronique. La nouvelle construction a été proposée et les exigences concernant la structure photorésistance discret-continu ont été déterminées par l'emploi des deux méthodes de calcul numérique et analytique. De nouvelles structures du dispositif de retard des signaux impulsionnels dans la gamme des millisecondes avec une durée de retard réglable à commande par coordonnées aussi bien que du vidéocapteur positionnel bidimensionnel sont proposées. Une nouvelle méthode de l'augmentation de sensibilité de ce vidéocapteur aux obstacles optiques, basée sur la dépendance du temps de la photoréponse du niveau d

  13. Detector apparatus having a hybrid pixel-waveform readout system

    DOEpatents

    Meng, Ling-Jian

    2014-10-21

    A gamma ray detector apparatus comprises a solid state detector that includes a plurality of anode pixels and at least one cathode. The solid state detector is configured for receiving gamma rays during an interaction and inducing a signal in an anode pixel and in a cathode. An anode pixel readout circuit is coupled to the plurality of anode pixels and is configured to read out and process the induced signal in the anode pixel and provide triggering and addressing information. A waveform sampling circuit is coupled to the at least one cathode and configured to read out and process the induced signal in the cathode and determine energy of the interaction, timing of the interaction, and depth of interaction.

  14. Readout of TPC Tracking Chambers with GEMs and Pixel Chip

    SciTech Connect

    Kadyk, John; Kim, T.; Freytsis, M.; Button-Shafer, J.; Kadyk, J.; Vahsen, S.E.; Wenzel, W.A.

    2007-12-21

    Two layers of GEMs and the ATLAS Pixel Chip, FEI3, have been combined and tested as a prototype for Time Projection Chamber (TPC) readout at the International Linear Collider (ILC). The double-layer GEM system amplifies charge with gain sufficient to detect all track ionization. The suitability of three gas mixtures for this application was investigated, and gain measurements are presented. A large sample of cosmic ray tracks was reconstructed in 3D by using the simultaneous timing and 2D spatial information from the pixel chip. The chip provides pixel charge measurement as well as timing. These results demonstrate that a double GEM and pixel combination, with a suitably modified pixel ASIC, could meet the stringent readout requirements of the ILC.

  15. Status of the CMS Phase I pixel detector upgrade

    NASA Astrophysics Data System (ADS)

    Spannagel, S.

    2016-09-01

    A new pixel detector for the CMS experiment is being built, owing to the instantaneous luminosities anticipated for the Phase I Upgrade of the LHC. The new CMS pixel detector provides four-hit tracking while featuring a significantly reduced material budget as well as new cooling and powering schemes. A new front-end readout chip mitigates buffering and bandwidth limitations, and comprises a low-threshold comparator. These improvements allow the new pixel detector to sustain and improve the efficiency of the current pixel tracker at the increased requirements imposed by high luminosities and pile-up. This contribution gives an overview of the design of the upgraded pixel detector and the status of the upgrade project, and presents test beam performance measurements of the production read-out chip.

  16. Attenuating Stereo Pixel-Locking via Affine Window Adaptation

    NASA Technical Reports Server (NTRS)

    Stein, Andrew N.; Huertas, Andres; Matthies, Larry H.

    2006-01-01

    For real-time stereo vision systems, the standard method for estimating sub-pixel stereo disparity given an initial integer disparity map involves fitting parabolas to a matching cost function aggregated over rectangular windows. This results in a phenomenon known as 'pixel-locking,' which produces artificially-peaked histograms of sub-pixel disparity. These peaks correspond to the introduction of erroneous ripples or waves in the 3D reconstruction of truly Rat surfaces. Since stereo vision is a common input modality for autonomous vehicles, these inaccuracies can pose a problem for safe, reliable navigation. This paper proposes a new method for sub-pixel stereo disparity estimation, based on ideas from Lucas-Kanade tracking and optical flow, which substantially reduces the pixel-locking effect. In addition, it has the ability to correct much larger initial disparity errors than previous approaches and is more general as it applies not only to the ground plane.

  17. Using an Active Pixel Sensor In A Vertex Detector

    SciTech Connect

    Matis, Howard S.; Bieser, Fred; Chen, Yandong; Gareus, Robin; Kleinfelder, Stuart; Oldenburg, Markus; Retiere, Fabrice; Ritter, HansGeorg; Wieman, Howard H.; Wurzel, Samuel E.; Yamamoto, Eugene

    2004-04-22

    Research has shown that Active Pixel CMOS sensors can detect charged particles. We have been studying whether this process can be used in a collider environment. In particular, we studied the effect of radiation with 55 MeV protons. These results show that a fluence of about 2 x 10{sup 12} protons/cm{sup 2} reduces the signal by a factor of two while the noise increases by 25%. A measurement 6 months after exposure shows that the silicon lattice naturally repairs itself. Heating the silicon to 100 C reduced the shot noise and increased the collected charge. CMOS sensors have a reduced signal to noise ratio per pixel because charge diffuses to neighboring pixels. We have constructed a photogate to see if this structure can collect more charge per pixel. Results show that a photogate does collect charge in fewer pixels, but it takes about 15 ms to collect all of the electrons produced by a pulse of light.

  18. Research on ionospheric tomography based on variable pixel height

    NASA Astrophysics Data System (ADS)

    Zheng, Dunyong; Li, Peiqing; He, Jie; Hu, Wusheng; Li, Chaokui

    2016-05-01

    A novel ionospheric tomography technique based on variable pixel height was developed for the tomographic reconstruction of the ionospheric electron density distribution. The method considers the height of each pixel as an unknown variable, which is retrieved during the inversion process together with the electron density values. In contrast to conventional computerized ionospheric tomography (CIT), which parameterizes the model with a fixed pixel height, the variable-pixel-height computerized ionospheric tomography (VHCIT) model applies a disturbance to the height of each pixel. In comparison with conventional CIT models, the VHCIT technique achieved superior results in a numerical simulation. A careful validation of the reliability and superiority of VHCIT was performed. According to the results of the statistical analysis of the average root mean square errors, the proposed model offers an improvement by 15% compared with conventional CIT models.

  19. Analysis of Multipath Pixels in SAR Images

    NASA Astrophysics Data System (ADS)

    Zhao, J. W.; Wu, J. C.; Ding, X. L.; Zhang, L.; Hu, F. M.

    2016-06-01

    As the received radar signal is the sum of signal contributions overlaid in one single pixel regardless of the travel path, the multipath effect should be seriously tackled as the multiple bounce returns are added to direct scatter echoes which leads to ghost scatters. Most of the existing solution towards the multipath is to recover the signal propagation path. To facilitate the signal propagation simulation process, plenty of aspects such as sensor parameters, the geometry of the objects (shape, location, orientation, mutual position between adjacent buildings) and the physical parameters of the surface (roughness, correlation length, permittivity)which determine the strength of radar signal backscattered to the SAR sensor should be given in previous. However, it's not practical to obtain the highly detailed object model in unfamiliar area by field survey as it's a laborious work and time-consuming. In this paper, SAR imaging simulation based on RaySAR is conducted at first aiming at basic understanding of multipath effects and for further comparison. Besides of the pre-imaging simulation, the product of the after-imaging, which refers to radar images is also taken into consideration. Both Cosmo-SkyMed ascending and descending SAR images of Lupu Bridge in Shanghai are used for the experiment. As a result, the reflectivity map and signal distribution map of different bounce level are simulated and validated by 3D real model. The statistic indexes such as the phase stability, mean amplitude, amplitude dispersion, coherence and mean-sigma ratio in case of layover are analyzed with combination of the RaySAR output.

  20. Evolution of opto-electronic properties during film formation of complex semiconductors

    PubMed Central

    Heinemann, M. D.; Mainz, R.; Österle, F.; Rodriguez-Alvarez, H.; Greiner, D.; Kaufmann, C. A.; Unold, T.

    2017-01-01

    Optical and electrical properties of complex semiconducting alloys like Cu(In,Ga)Se2 (CIGS) are strongly influenced by the reaction pathways occurring during their deposition process. This makes it desirable to observe and control these properties in real-time during the deposition. Here we show for the first time the evolution of the band gap and the sub-band-gap defect absorption of CIGS thin film as well as surface roughness during a three-stage co-evaporation process by means of an optical analysis technique, based on white light reflectometry (WLR). By simultaneously recording structural information with in-situ energy dispersive X-ray diffraction and X-ray fluorescence we can directly correlate the evolution of opto-electronic material parameters with the structural properties of the film during growth. We find that the surface roughness and the sub-gap light absorption can be correlated with the phase evolution during the transformation from (In,Ga)2Se3 to Cu(In,Ga)Se2 by the incorporation of Cu into the film. Sub-bandgap light absorption is found to be influenced by the Cu-saturated growth phase and is lowered close to the points of stoichiometry, allowing for an advanced process design. PMID:28374745

  1. Opto-photo-thermo-elastic displacement detection using coherent confocal microscope

    NASA Astrophysics Data System (ADS)

    Eliyahu, Igal; DiMarzio, Charles A.

    2009-02-01

    Photothermal spectroscopy is a powerful tool to investigate the optical absorption and thermal characteristics of a sample. The photo-thermal effect, that is the basis for photothermal spectroscopy, is the conversion of optical energy into heat. Photothermal spectroscopy is implemented in a variety of methods. Biomedical imaging applications commonly implement the Photo-Thermo-Acoustic (PTA) method, that is based on measuring the acoustic pressure wave that propagates due to the photothermal effect, caused by absorption of energy from a heating laser. This research demonstrates photothermal elastic displacement measurement using a coherent confocal microscope, as a first step towered pothothermal spectroscopy. The high accuracy of the interferometer, that is the heart of the coherent confocal microscope, in detecting small changes in position makes it intrinsically adequate to measure the thermoelastic expansion of the sample that results from the photothermal process. In this research Polyvinyl-Chloride Plastisol (PVCP) samples, constructed with different absorption coefficients, were tested using different heating light fluences. The results are compared against an approximate theoretical model and are found to be in good agreement. The Opto-Photo-Thermo-Elastic (Optical detection of elastic displacement changes due to the phototheraml process) technique is demonstrated in this research as a first step toward extending the capability of confocal microscopes to image deeper into tissues than is presently possible, and to detect new modes of contrast.

  2. Opto-mechanical design of optical window for aero-optics effect simulation instruments

    NASA Astrophysics Data System (ADS)

    Wang, Guo-ming; Dong, Dengfeng; Zhou, Weihu; Ming, Xing; Zhang, Yan

    2016-10-01

    A complete theory is established for opto-mechanical systems design of the window in this paper, which can make the design more rigorous .There are three steps about the design. First, the universal model of aerodynamic environment is established based on the theory of Computational Fluid Dynamics, and the pneumatic pressure distribution and temperature data of optical window surface is obtained when aircraft flies in 5-30km altitude, 0.5-3Ma speed and 0-30°angle of attack. The temperature and pressure distribution values for the maximum constraint is selected as the initial value of external conditions on the optical window surface. Then, the optical window and mechanical structure are designed, which is also divided into two parts: First, mechanical structure which meet requirements of the security and tightness is designed. Finally, rigorous analysis and evaluation are given about the structure of optics and mechanics we have designed. There are two parts to be analyzed. First, the Fluid-Solid-Heat Coupled Model is given based on finite element analysis. And the deformation of the glass and structure can be obtained by the model, which can assess the feasibility of the designed optical windows and ancillary structure; Second, the new optical surface is fitted by Zernike polynomials according to the deformation of the surface of the optical window, which can evaluate imaging quality impact of spectral camera by the deformation of window.

  3. Experimental opto-digital processing of multiple data via modulation, packaging and encryption

    NASA Astrophysics Data System (ADS)

    Trejos, Sorayda; Fredy Barrera, John; Tebaldi, Myrian; Torroba, Roberto

    2014-05-01

    A new opto-digital protocol to handle multiple data in an efficient and secure way is proposed and experimentally demonstrated. In this method, the optical processor is a 2f system with a ground glass located in its input plane. The 2f system is placed in one arm of a Mach-Zehnder interferometer. The optically processed data are holographically stored and then filtered, theta modulated and multiplexed to obtain a single package containing all processed data. During the filtering procedure, the non-relevant information contained in the holograms is eliminated. Otherwise, these non-relevant data will introduce noise over the output plane affecting the retrieved objects. In this case, the theta modulation process performed with a grating allows recovering all data without superposition. In order to get the encrypted package a second random phase masks multiplies the package. The recovering procedure consists in multiplying the encrypted package by the complex conjugate of the random phase mask, an after a Fourier transform operation all data are retrieved. In this way, an authorized user recovers all data with a single operation, in the same plane and at the same time without noise or superposition. Experimental results demonstrate the validity and applicability of the proposal.

  4. Optimized deposition and characterization of nanocrystalline magnesium indium oxide thin films for opto-electronic applications

    SciTech Connect

    Raj, A. Moses Ezhil; Ravidhas, C.; Ravishankar, R.; Kumar, A. Rathish; Selvan, G.; Jayachandran, M.; Sanjeeviraja, C.

    2009-05-06

    Transparent conducting magnesium indium oxide films (MgIn{sub 2}O{sub 4}) were deposited on to quartz substrates without a buffer layer at an optimized deposition temperature of 450 deg. C to achieve high transmittance in the visible spectral range and electrical conductivity in the low temperature region. Magnesium ions are distributed over the tetrahedral and octahedral sites of the inverted spinel structure with preferential orientation along (3 1 1) Miller plane. The possible mechanism that promotes conductivity in this system is the charge transfer between the resident divalent (Mg{sup 2+}) and trivalent (In{sup 3+}) cations in addition to the available oxygen vacancies in the lattice. A room temperature electrical conductivity of 1.5 x 10{sup -5} S cm{sup -1} and an average transmittance >75% have been achieved. Hall measurements showed n-type conductivity with electron mobility value 0.95 x 10{sup -2} cm{sup 2} V{sup -1} s{sup -1} and carrier concentration 2.7 x 10{sup 19} cm{sup -3}. Smoothness of the film surface observed through atomic force microscope measurements favors this material for gas sensing and opto-electronic device development.

  5. A universal label-free biosensing platform based on opto-fluidic ring resonators

    NASA Astrophysics Data System (ADS)

    Zhu, Hongying; White, Ian M.; Suter, Jonathan D.; Gohring, John; Fan, Xudong

    2009-02-01

    Rapid and accurate detection of biomolecules is important for medical diagnosis, pharmaceuticals, homeland security, food quality control, and environmental protection. A simple, low cost and highly sensitive label-free optical biosensor based on opto-fluidic ring resonator (OFRR) has been developed that naturally integrates microfluidics with ring resonators. The OFRR employs a piece of fused silica capillary with a diameter around 100 micrometers. The circular cross section of the capillary forms the ring resonator and light repeatedly travels along the resonator circumference in the form of whispering gallery modes (WGMs) through total internal reflection. When the capillary wall is as thin as a couple of micrometers (< 4 μm), an evanescent field of the WGMs exists at the OFRR inner surface and interacts with the sample when it flows through the OFRR. In order to detect the target molecules with high specificity, the OFRR inner surface is functionalized with receptors, such as antibodies, peptide-displayed bacteriophage or oligonucleotide DNA probes. The WGM spectral position shifts when biomolecules bind to the OFRR inner surface and change the local refractive index, which provides quantitative and kinetic information about the biomolecule interaction near the OFRR inner surface. The OFRR has been successfully demonstrated for detection of various types of biomoelcuels. Here, we will first introduce the basic operation principle of the OFRR as a sensor and then application examples of the OFRR in the detection of proteins, disease biomarkers, virus, DNA molecules, and cells with high sensitivities will be presented.

  6. Innovative opto-mechanical design of a laser head for compact thin-disk

    NASA Astrophysics Data System (ADS)

    Macúchová, Karolina; Smrž, Martin; Řeháková, Martina; Mocek, Tomáš

    2016-11-01

    We present recent progress in design of innovative versatile laser head for lasers based on thin-disk architecture which are being constructed at the HiLASE centre of the IOP in the Czech Republic. Concept of thin-disk laser technology allows construction of lasers providing excellent beam quality with high average output power and optical efficiency. Our newly designed thin-disk carrier and pump module comes from optical scheme consisting of a parabolic mirror and roof mirrors proposed in 90's. However, mechanical parts and a cooling system were in-house simplified and tailor-made to medium power lasers since no suitable setup was commercially available. Proposed opto-mechanical design is based on stable yet easily adjustable mechanics. The only water nozzle-cooled component is a room-temperature-operated thindisk mounted on a special cooling finger. Cooling of pump optics was replaced by heat conductive transfer from mirrors made of special Al alloy to a massive brass baseplate. Such mirrors are easy to manufacture and very cheap. Presented laser head was manufactured and tested in construction of Er and Yb doped disk lasers. Details of the latest design will be presented.

  7. Opto-thermal analysis of a lightweighted mirror for solar telescope.

    PubMed

    Banyal, Ravinder K; Ravindra, B; Chatterjee, S

    2013-03-25

    In this paper, an opto-thermal analysis of a moderately heated lightweighted solar telescope mirror is carried out using 3D finite element analysis (FEA). A physically realistic heat transfer model is developed to account for the radiative heating and energy exchange of the mirror with surroundings. The numerical simulations show the non-uniform temperature distribution and associated thermo-elastic distortions of the mirror blank clearly mimicking the underlying discrete geometry of the lightweighted substrate. The computed mechanical deformation data is analyzed with surface polynomials and the optical quality of the mirror is evaluated with the help of a ray-tracing software. The thermal print-through distortions are further shown to contribute to optical figure changes and mid-spatial frequency errors of the mirror surface. A comparative study presented for three commonly used substrate materials, namely, Zerodur, Pyrex and Silicon Carbide (SiC) is relevant to vast area of large optics requirements in ground and space applications.

  8. Hydrogen-Bonded Organic Semiconductor Micro- And Nanocrystals: From Colloidal Syntheses to (Opto-)Electronic Devices

    PubMed Central

    2014-01-01

    Organic pigments such as indigos, quinacridones, and phthalocyanines are widely produced industrially as colorants for everyday products as various as cosmetics and printing inks. Herein we introduce a general procedure to transform commercially available insoluble microcrystalline pigment powders into colloidal solutions of variously sized and shaped semiconductor micro- and nanocrystals. The synthesis is based on the transformation of the pigments into soluble dyes by introducing transient protecting groups on the secondary amine moieties, followed by controlled deprotection in solution. Three deprotection methods are demonstrated: thermal cleavage, acid-catalyzed deprotection, and amine-induced deprotection. During these processes, ligands are introduced to afford colloidal stability and to provide dedicated surface functionality and for size and shape control. The resulting micro- and nanocrystals exhibit a wide range of optical absorption and photoluminescence over spectral regions from the visible to the near-infrared. Due to excellent colloidal solubility offered by the ligands, the achieved organic nanocrystals are suitable for solution processing of (opto)electronic devices. As examples, phthalocyanine nanowire transistors as well as quinacridone nanocrystal photodetectors, with photoresponsivity values by far outperforming those of vacuum deposited reference samples, are demonstrated. The high responsivity is enabled by photoinduced charge transfer between the nanocrystals and the directly attached electron-accepting vitamin B2 ligands. The semiconducting nanocrystals described here offer a cheap, nontoxic, and environmentally friendly alternative to inorganic nanocrystals as well as a new paradigm for obtaining organic semiconductor materials from commercial colorants. PMID:25253644

  9. Acousto-opto-mechanical theory for polarization maintaining optical fibers in Brillouin based sensing

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoling; Ansari, Farhad; Meng, Dewei; Bao, Tengfei

    2015-01-01

    Change in phase or wavelength for interferometric and fiber Bragg Gratings (FBG) based sensors can be described by strain-optic effects. In Brillouin sensors, strain sensitivity need to be expressed in terms of acousto-opto-mechanical properties of fibers. It is then possible to formulate theoretical relationships that lead to the evaluation of strain sensitivities and establishment of gauge factors for Brillouin based sensors. This article reports on the derivation of generalized relationships describing the strain sensitivity in terms of acousto-optic effects in optical fibers. In particular, the formulations correspond to polarization maintaining fibers at various polarization angles with respect to the slow axis of the fiber. The scope of research encompassed theoretical and experimental studies involving both single mode as well as polarization maintaining optical fibers subjected to strain under isothermal conditions. A high resolution BOTDA was employed in the experiments in order to verify the validity of theoretical relationships between strain and Brillouin frequency shifts for different polarization angles.

  10. Development of an opto-electronic fiber device with multiple nano-probes

    NASA Astrophysics Data System (ADS)

    Mehta, N.; Cocking, A.; Zhang, C.; Ma, D.; Xu, Y.; Liu, Z.

    2016-11-01

    We present the fabrication and characterization of an opto-electronic fiber device which can allow for both electromechanical functionality and optical waveguiding capability. The air holes of a photonic crystal fiber are selectively sealed and then pumped with molten metal under pressure. The metal filled holes act as electrodes to which individual carbon nanotubes (CNT) are attached precisely by a laser-welding technique or a focused ion beam assisted pick-and-bond technique. The optical modal profile and the group velocity dispersion of the fabricated device are studied both numerically and experimentally. We also present preliminary experimental proof showing the feasibility of electric actuation of a pair of nanotubes by applying up to 40 V potential difference between the filled electrodes. Furthermore, numerical simulations are carried out which agree with the experimentally observed displacement of the CNT upon electric actuation. The unique aspect of our device is that it provides optical waveguiding and electromechanical nano-probing capability in a single package. Such combined functionality can potentially enable simultaneous electrical and optical manipulation and interrogation at the nanoscale.

  11. Development of an opto-hydrodynamic process to remove nanoparticles from solid surfaces

    NASA Astrophysics Data System (ADS)

    Ahn, Daehwan; Ha, Jeonghong; Kim, Dongsik

    2013-01-01

    We developed a surface cleaning process to remove nanoscale contaminants as small as 10 nm from solid surfaces using a laser-induced micro liquid jet. In the process, laser-induced breakdown of a micron-sized water droplet (∼10 nl) produces a high-speed jet with speeds up to 1600 m/s liquid jet via an explosive vaporization process. Impingement of the liquid jet with atomized droplets on the contaminated substrate removes the nanoparticles under the hydrodynamic drag forces. The process parameters, including the incident laser energy and the position of the droplet relative to the laser focus, were optimized to maximize the cleaning power. Polystyrene latex particles 20, 30, or 90 nm in diameter and Al2O3 particles 10-50 nm in diameter were used to demonstrate the cleaning performance of the opto-hydrodynamic cleaning technique. The proposed cleaning process is expected to be useful for selectively cleaning local areas with minimal exposure to water.

  12. Modeling opto-electronic properties of a dye molecule in proximity of a semiconductor nanoparticle

    NASA Astrophysics Data System (ADS)

    Delgado, Alain; Corni, Stefano; Goldoni, Guido

    2013-07-01

    A general methodology is presented to model the opto-electronic properties of a dye molecule in the presence of a semiconductor nanoparticle (NP), a model system for the architecture of dye-sensitized solar cells. The method is applied to the L0 organic dye solvated with acetonitrile in the neighborhood of a TiO2 NP. The total reaction potential due to the polarization of the solvent and the metal oxide is calculated by extending the polarizable continuum model integral equation formalism. The ground state energy is computed by using density functional theory (DFT) while the vertical electronic excitations are obtained by time-dependent DFT in a state-specific corrected linear response scheme. We calculate the excited state oxidation potential (ESOP) for the protonated and deprotonated forms of the L0 dye at different distances and configurations with respect to the NP surface. The stronger renormalizations of the ESOP values due to the presence of the TiO2 nanostructure are found for the protonated dye, reaching a maximum of about -0.15 eV. The role of protonation effect is discussed in terms of the atomic Löwdin charges of the oxidized and reduced species. On the other hand, we observed a weak effect on the L0 optical excitation gap due to the polarization response of the NP.

  13. A novel opto-electromagnetic actuator coupled to the tympanic membrane.

    PubMed

    Lee, Chia-Fone; Shih, Chih-Hua; Yu, Jen-Fang; Chen, Jyh-Horng; Chou, Yuan-Fang; Liu, Tien-Chen

    2008-12-05

    A new type of electromagnetic vibration transducer designed to be placed onto the tympanic membrane was developed. The actuator consisted of two photodiodes, two permanent magnets, an aluminum ring, two opposing wound coils, a latex membrane and a Provil Novo membrane. An optic probe was designed to allow sound and light signals to enter the ear canal, thereby preventing the acoustic occlusion effect of traditional ear molds. Two light-emitting diodes were used for carrying the input signals. The corresponding photodiodes were used for receiving the light signals and generating currents in the actuator. The opto-electromagnetic vibration actuator was fabricated and tested using a Laser Doppler vibrometer. The actuator showed displacements of vibration between 30 and 1 nm from 300 to 6500Hz and reduced in amplitude at higher frequencies. The average gain of the actuator with 140microA on the umbo displacement was about 20 dB relative to 87 dBA at the distance of 6cm from the tympanic membrane and 0microA in actuator.

  14. Numerical study of opto-fluidic ring resonators for biosensor applications.

    PubMed

    Cho, Han Keun; Han, Jinwoo

    2012-10-22

    The opto-fluidic ring resonator (OFRR) biosensor is numerically characterized in whispering gallery mode (WGM). The ring resonator includes a ring, a waveguide and a gap separating the ring and the waveguide. Dependence of the resonance characteristics on the resonator size parameters such as the ring diameter, the ring thickness, the waveguide width, and the gap width between the ring and the waveguide are investigated. For this purpose, we use the finite element method with COMSOL Multiphysics software to solve the Maxwell's equations. The resonance frequencies, the free spectral ranges (FSR), the full width at half-maximum (FWHM), finesse (F), and quality factor of the resonances (Q) are examined. The resonant frequencies are dominantly affected by the resonator diameter while the gap width, the ring thickness and the waveguide width have negligible effects on the resonant frequencies. FWHM, the quality factor Q and the finesse F are most strongly affected by the gap width and moderately influenced by the ring diameter, the waveguide width and the ring thickness. In addition, our simulation demonstrates that there is an optimum range of the waveguide width for a given ring resonator and this value is between ~2.25 μm and ~2.75 μm in our case.

  15. A Large Aperture Fabry-Perot Tunable Filter Based On Micro Opto Electromechanical Systems Technology

    NASA Technical Reports Server (NTRS)

    Greenhouse, Matt; Mott, Brent; Powell, Dan; Barclay, Rich; Hsieh, Wen-Ting

    2002-01-01

    A research and development effort sponsored by the NASA Goddard Spaceflight Center (GSFC) is focused on applying Micro Opto Electromechanical Systems (MOEMS) technology to create a miniature Fabry-Perot tunable etalon for space and ground-based near infrared imaging spectrometer applications. Unlike previous devices developed for small-aperture telecommunications systems, the GSFC research is directed toward a novel 12 - 40 mm aperture for astrophysical studies, including emission line imaging of galaxies and nebulae, and multi-spectral redshift surveys in the 1.1 - 2.3 micron wavelength region. The MOEMS design features integrated electrostatic scanning of the 11-micron optical gap, and capacitance micrometry for closed loop control of parallelism within a 10-nm tolerance. The low thermal mass and inertia inherent in MOEMS devices allows for rapid cooling to the proposed 30 K operating temperature, and high frequency response. Achieving the proposed 6-nm aperture flatness (with an effective finesse of 50) represents the primary technical challenge in the current 12-mm prototype.

  16. Micro-opto-mechanical devices and systems using epitaxial lift off

    NASA Technical Reports Server (NTRS)

    Camperi-Ginestet, C.; Kim, Young W.; Wilkinson, S.; Allen, M.; Jokerst, N. M.

    1993-01-01

    The integration of high quality, single crystal thin film gallium arsenide (GaAs) and indium phosphide (InP) based photonic and electronic materials and devices with host microstructures fabricated from materials such as silicon (Si), glass, and polymers will enable the fabrication of the next generation of micro-opto-mechanical systems (MOMS) and optoelectronic integrated circuits. Thin film semiconductor devices deposited onto arbitrary host substrates and structures create hybrid (more than one material) near-monolithic integrated systems which can be interconnected electrically using standard inexpensive microfabrication techniques such as vacuum metallization and photolithography. These integrated systems take advantage of the optical and electronic properties of compound semiconductor devices while still using host substrate materials such as silicon, polysilicon, glass and polymers in the microstructures. This type of materials optimization for specific tasks creates higher performance systems than those systems which must use trade-offs in device performance to integrate all of the function in a single material system. The low weight of these thin film devices also makes them attractive for integration with micromechanical devices which may have difficulty supporting and translating the full weight of a standard device. These thin film devices and integrated systems will be attractive for applications, however, only when the development of low cost, high yield fabrication and integration techniques makes their use economically feasible. In this paper, we discuss methods for alignment, selective deposition, and interconnection of thin film epitaxial GaAs and InP based devices onto host substrates and host microstructures.

  17. Opto-acoustic study of tinuvin-P and rhodamine 6G in solid polymeric matrices

    NASA Astrophysics Data System (ADS)

    Nonell, S.; Martí, C.; García-Moreno, I.; Costela, Á.; Sastre, R.

    Laser-induced opto-acoustic calorimetry has been used to examine the thermo-elastic properties of two polymer matrices doped with tinuvin-P and the radiation-less decay processes of rhodamine 6G (Rh6G) in them. The matrices assayed were methyl methacrylate (MMA) homopolymers P(MMA), and methyl methacrylate and 2-hydroxyethyl methacrylate (HEMA) copolymers P(MMA:HEMA). A slight difference in the thermo-elastic properties of the polymers, namely their adiabatic expansion coefficients, has been detected and found to correlate with the long-term stability of the laser material. This suggests a key role of the heat-dissipation processes in the photostability of these polymeric materials. On the other hand, the fluorescence quantum yield of Rh6G is shown to vary with the polymer-matrix composition in a way consistent with its lasing efficiency. The Rh6G absorption and fluorescence quantum yield also change dramatically upon increasing its concentration, which suggests the co-existence of different Rh6G forms with different photophysical properties.

  18. Thermally evaporated mechanically hard tin oxide thin films for opto-electronic apllications

    NASA Astrophysics Data System (ADS)

    Tripathy, Sumanta K.; Rajeswari, V. P.

    2014-01-01

    Tungsten doped tin oxide (WTO) and Molybdenum doped tin oxide (MoTO) thin film were deposited on corn glass by thermal evaporation method. The films were annealed at 350°C for one hour. Structural analysis using Xray diffraction data shows both the films are polycrystalline in nature with monoclinic structure of tin oxide, Sn3O4, corresponding to JCPDS card number 01-078-6064. SEM photograph showed that both the films have spherical grains with size in the range of 20-30 nm. Compositional analysis was carried out using EDS which reveals the presence of Sn, O and the dopant Mo/W only thereby indicating the absence of any secondary phase in the films. The films are found to contain nearly 6 wt% of Mo, 8 wt% of W as dopants respectively. The transmission pattern for both the films in the spectral range 200 - 2000 nm shows that W doping gives a transparency of nearly 80% from 380 nm onwards while Mo doping has less transparency of 39% at 380nm. Film hardness measurement using Triboscope shows a film hardness of about 9-10 GPa for both the films. It indicates that W or M doping in tin oxide provides the films the added advantage of withstanding the mechanical wear and tear due to environmental fluctuations By optimizing the optical and electrical properties, W/Mo doped tin oxide films may be explored as window layers in opto-electronic applications such as solar cells.

  19. Realization of Ultra-High Spectral Purity with the Opto-Electronic Oscillator

    NASA Technical Reports Server (NTRS)

    Yao, Steve; Maleki, Lute; Ji, Yu; Dick, John

    2000-01-01

    Recent results with the Opto-Electronic Oscillator (OEO) have led to the realization of very high spectral purity. Experimental results have produced a performance characterized by a noise as low as by -50 dBc/Hz at 10 Hz for a 10 GHz OEO. The unit was built in a compact package containing an integrated DFB laser and the modulator. This performance is significant because the oscillator is free running, and since the noise in an OEO is independent of the oscillation frequency, the same result can also be obtained at higher frequencies. The result also demonstrates that high frequency, high performance, low cost, and miniature OEO can be realized with the integrated photonic technology. We have also developed a novel carrier suppression technique to reduce the 1/f phase noise of the oscillator even further. The technique is based on the use of a long fiber delay, in place of the high Q cavity, to implement carrier suppression. Our preliminary experimental results indicate an extra 10 to 20 dB phase noise reduction of the OEO with this novel technique. Further noise reduction beyond this value is expected with improved circuit design and longer reference fiber.

  20. OptoSci educator kits: an immediate solution to photonics teaching laboratories

    NASA Astrophysics Data System (ADS)

    Walsh, Douglas; Moodie, David; Mauchline, Iain; Johnstone, Walter; Culshaw, Brian

    2003-10-01

    The burgeoning growth of the worldwide photonics and optical communications industry has imposed ever increasing demands on the supply of suitably skilled engineers and scientists who can design, install and operate modern photonics systems. In recognition of this need OptoSci, in collaboration with university academics, has commercially developed a series of hardware based teaching packages in optics, optoelectronics and optical communications. Each educator kit is fully self-contained, including all of the optoelectronic hardware and comprehensive literature support. This saves the academic tutor considerable development time and enables the kits to be immediately installed in the photonics teaching laboratory to support accompanying lecture courses. A fundamental design objective of our educator kits is to provide students with hands-on practical experience of photonics components, instruments and systems and allow them to investigate essential physical principles and key technical issues relevant to their lecture courses. This paper will outline the design philosophy behind the products to meet the desired educational aims, and then examine the specific educational objectives and topics investigated in each educator kit.

  1. The ASTRI SST-2M prototype for the Cherenkov Telescope Array: opto-mechanical performance

    NASA Astrophysics Data System (ADS)

    Canestrari, Rodolfo; Giro, Enrico; Sironi, Giorgia; Antolini, Elisa; Fugazza, Dino; Scuderi, Salvatore; Tosti, Gino; Tanci, Claudio; Russo, Federico; Gardiol, Daniele; Fermino, Carlos Eduardo; Stringhetti, Luca; Pareschi, Giovanni; Marchiori, G.; Busatta, A.; Marcuzzi, E.; Folla, I.

    2016-08-01

    ASTRI SST-2M is an end-to-end telescope prototype developed by the Italian National Institute of Astrophysics (INAF) in the framework of the Cherenkov Telescope Array (CTA). The CTA observatory, with a combination of large-, medium-, and small-sized telescopes (LST, MST and SST, respectively), will represent the next generation of imaging atmospheric Cherenkov telescopes. It will explore the very high-energy domain from a few tens of GeV up to few hundreds of TeV. The ASTRI SST-2M telescope structure and mirrors have been installed at the INAF observing station at Serra La Nave, on Mt. Etna (Sicily, Italy) in September 2014. Its performance verification phase began in autumn 2015. Part of the scheduled activities foresees the study and characterization of the optical and opto-mechanical performance of the telescope prototype. In this contribution we report the results achieved in terms of kinematic model analysis, mirrors reflectivity evolution, telescopes positioning, flexures and pointing model and the thermal behavior.

  2. Forging Links.

    ERIC Educational Resources Information Center

    Stewig, John Warren

    Blacksmiths and their craft have changed with the times, and as times change for teachers, they too should be forgers of links. Teacher-to-teacher links should extend beyond the faculty lounge to support systems and active groups of individuals concerned about each other. Another personal link can be made by developing a grade level, system-wide…

  3. Intra-pixel response of infrared detector arrays for JWST

    NASA Astrophysics Data System (ADS)

    Hardy, Tim; Baril, M. R.; Pazder, J.; Stilburn, J. S.

    2008-07-01

    The near-infrared instruments on the James Webb Space Telescope will use 5 micron cutoff HAWAII-2RG detector arrays. We have investigated the response of this type of detector at sub-pixel resolution to determine whether variations at this scale would affect the performance of the instruments. Using a simple experimental setup we were able to get measurements with a resolution of approximately 4 microns. We have measured an un-hybridized HAWAII-1RG multiplexer, a hybridized HAWAII-1RG device with a 5 micron cutoff HgCdTe detector layer, and a hybridized HAWAII-2RG device with a 5 micron cutoff substrate-removed HgCdTe detector layer. We found that the intra-pixel response functions of the hybrid devices are basically smooth and well behaved, and vary little from pixel to pixel. However, we did find numerous sub-pixel sized defects, notably some long straight thin features like scratches. We were not able to detect any significant variations with wavelength between 0.65 and 2.2 microns, but in the -1RG device there was a variation with temperature. When cooled from 80K to 40K, the pixel response became narrower, and some signal began to be lost at the edges of the pixel. We believe this reflects a reduction in charge diffusion at the lower temperature.

  4. Monolithic pixels on moderate resistivity substrate and sparsifying readout architecture

    NASA Astrophysics Data System (ADS)

    Giubilato, P.; Battaglia, M.; Bisello, D.; Caselle, M.; Chalmet, P.; Demaria, L.; Ikemoto, Y.; Kloukinas, K.; Mansuy, S. C.; Mattiazzo, S.; Marchioro, A.; Mugnier, H.; Pantano, D.; Potenza, A.; Rivetti, A.; Rousset, J.; Silvestrin, L.; Snoeys, W.

    2013-12-01

    The LePix projects aim realizing a new generation monolithic pixel detectors with improved performances at lesser cost with respect to both current state of the art monolithic and hybrid pixel sensors. The detector is built in a 90 nm CMOS process on a substrate of moderate resistivity. This allows charge collection by drift while maintaining the other advantages usually offered by MAPS, like having a single piece detector and using a standard CMOS production line. The collection by drift mechanism, coupled to the low capacitance design of the collecting node made possible by the monolithic approach, provides an excellent signal to noise ratio straight at the pixel cell together with a radiation tolerance far superior to conventional un-depleted MAPS. The excellent signal-to-noise performance is demonstrated by the device ability to separate the 6 keV 55Fe double peak at room temperature. To achieve high granularity (10-20 μm pitch pixels) over large detector areas maintaining high readout speed, a completely new compressing architecture has been devised. This architecture departs from the mainstream hybrid pixel sparsification approach, which uses in-pixel logic to reduce data, by using topological compression to minimize pixel area and power consumption.

  5. Performance limits of a single photon counting pixel system

    NASA Astrophysics Data System (ADS)

    Chmeissani, M.; Mikulec, B.

    2001-03-01

    X-ray imaging using hybrid pixel detectors in single photon counting mode is a relatively recent and exciting development. The photon counting mode implies that each pixel has a threshold in energy above which a hit is recorded. Sharing of charge between adjacent pixels would therefore lead to a loss of registered hits and for medical imaging applications to a higher patient dose. This explains why the demand for high spatial resolution and consequently small pixel sizes (<100 μm) motivates the Medipix2 collaboration to study the effects of charge sharing between pixels on system performance. Two different simulation codes are used to simulate the energy loss inside the detector and the charge transport towards the pixel electrodes. The largest contribution to the lateral spreading of charge comes from diffusion and can result in a considerable loss of detection efficiency in photon counting systems for small pixel sizes. The Medipix2 collaboration consists of groups from Barcelona, Cagliari, CEA/Leti DEIN, CERN, Freiburg, Glasgow, Mitthögskolan, Napoli, NIKHEF, MRC lab Cambridge, Pisa, Prague and Sassari.

  6. A low light level sensor with dark current compensating pixels

    NASA Astrophysics Data System (ADS)

    Perley, Mitchell; Baxter, Patrick; Raynor, Jeffrey M.; Renshaw, David

    2008-09-01

    In ultra-low light conditions the presence of dark current becomes a major source of noise for a CMOS sensor. Standard dark current compensation techniques, such as using a dark reference frame, bring significant improvements to dark noise in typical applications. However, applications requiring long integration times mean that such techniques cannot always be used. This paper presents a differential dark current compensating pixel. The pixel is made up of a differential amplifier and two photodiodes: one light shielded photodiode connected to the non-inverting input of the opamp and a light detecting photodiode connected to the inverting input of the opamp. An integrating capacitor is used in the feedback loop to convert photocurrent to voltage, and a switched capacitor network is present in parallel with the light shielded pixel, which is used to satisfy the output equation to compensate the dark current. The pixel uses 150 μm x 150 μm photodiodes and is fabricated in a standard 0.18 μm, 6M1P, CMOS process. The results show that the pixel is light sensitive and has a linear output as expected. However, the dark current is not predictably controlled. Further work will be carried out on the pixel design, and particularly the switched capacitor circuit, to determine the cause of the non-predictability of the pixel output.

  7. Pixel Analysis and Plasma Dynamics Characterized by Photospheric Spectral Data

    NASA Astrophysics Data System (ADS)

    Rasca, A.; Chen, J.; Pevtsov, A. A.

    2015-12-01

    Continued advances in solar observations have led to higher-resolution magnetograms and surface (photospheric) images, revealing bipolar magnetic features operating near the resolution limit during emerging flux events and other phenomena used to predict solar eruptions responsible for geomagnetic plasma disturbances. However, line of sight (LOS) magnetogram pixels only contain the net uncanceled magnetic flux, which is expected to increase for fixed regions as resolution limits improve. A pixel dynamics model utilizing Stokes I spectral profiles was previously-used to quantify changes in the Doppler shift, width, asymmetry, and tail flatness of Fe I lines at 6301.5 and 6302.5 Å and used pixel-by-pixel line profile fluctuations to characterize quiet and active regions on the Sun. We use this pixel dynamics model with circularly polarized photospheric data (e.g., SOLIS data) to estimate plasma dynamic properties at a sub-pixel level. The analysis can be extended to include the full Stokes parameters and study signatures of magnetic fields and coupled plasma properties on sub-pixel scales.

  8. Monolithic pixel detectors with 0.2 μm FD-SOI pixel process technology

    NASA Astrophysics Data System (ADS)

    Miyoshi, Toshinobu; Arai, Yasuo; Chiba, Tadashi; Fujita, Yowichi; Hara, Kazuhiko; Honda, Shunsuke; Igarashi, Yasushi; Ikegami, Yoichi; Ikemoto, Yukiko; Kohriki, Takashi; Ohno, Morifumi; Ono, Yoshimasa; Shinoda, Naoyuki; Takeda, Ayaki; Tauchi, Kazuya; Tsuboyama, Toru; Tadokoro, Hirofumi; Unno, Yoshinobu; Yanagihara, Masashi

    2013-12-01

    Truly monolithic pixel detectors were fabricated with 0.2 μm SOI pixel process technology by collaborating with LAPIS Semiconductor Co., Ltd. for particle tracking experiment, X-ray imaging and medical applications. CMOS circuits were fabricated on a thin SOI layer and connected to diodes formed in the silicon handle wafer through the buried oxide layer. We can choose the handle wafer and therefore high-resistivity silicon is also available. Double SOI (D-SOI) wafers fabricated from Czochralski (CZ)-SOI wafers were newly obtained and successfully processed in 2012. The top SOI layers are used as electric circuits and the middle SOI layers used as a shield layer against the back-gate effect and cross-talk between sensors and CMOS circuits, and as an electrode to compensate for the total ionizing dose (TID) effect. In 2012, we developed two SOI detectors, INTPIX5 and INTPIX3g. A spatial resolution study was done with INTPIX5 and it showed excellent performance. The TID effect study with D-SOI INTPIX3g detectors was done and we confirmed improvement of TID tolerance in D-SOI sensors.

  9. Pixel detectors in 3D technologies for high energy physics

    SciTech Connect

    Deptuch, G.; Demarteau, M.; Hoff, J.; Lipton, R.; Shenai, A.; Yarema, R.; Zimmerman, T.; /Fermilab

    2010-10-01

    This paper reports on the current status of the development of International Linear Collider vertex detector pixel readout chips based on multi-tier vertically integrated electronics. Initial testing results of the VIP2a prototype are presented. The chip is the second embodiment of the prototype data-pushed readout concept developed at Fermilab. The device was fabricated in the MIT-LL 0.15 {micro}m fully depleted SOI process. The prototype is a three-tier design, featuring 30 x 30 {micro}m{sup 2} pixels, laid out in an array of 48 x 48 pixels.

  10. Status and Construction of the Belle II DEPFET pixel system

    NASA Astrophysics Data System (ADS)

    Lütticke, Florian

    2014-06-01

    DEpleted P-channel Field Effect Transistor (DEPFET) active pixel detectors combine detection with a first amplification stage in a fully depleted detector, resulting in an superb signal-to-noise ratio even for thin sensors. Two layers of thin (75 micron) silicon DEPFET pixels will be used as the innermost vertex system, very close to the beam pipe in the Belle II detector at the SuperKEKB facility. The status of the 8 million DEPFET pixels detector, latest developments and current system tests will be discussed.

  11. Matching faces and expressions in pixelated and blurred photos.

    PubMed

    White, Murray; Li, Judy

    2006-01-01

    Matching the emotional expressions of pairs of face photos was slower with pixelated and blurred photos than with original, untransformed photos. Matching the identities of the same face pairs was unaffected by pixelation and blurring. Because pixelation and blurring degrade higher spatial frequencies carrying edge-based information that define feature shape more than lower frequencies carrying configural properties, these findings converge with findings for line drawings and negative photos in showing that expression and face recognition processes differ in their reliance on edge-based and configural information.

  12. Vertically integrated pixel readout chip for high energy physics

    SciTech Connect

    Deptuch, Grzegorz; Demarteau, Marcel; Hoff, James; Khalid, Farah; Lipton, Ronald; Shenai, Alpana; Trimpl, Marcel; Yarema, Raymond; Zimmerman, Tom; /Fermilab

    2011-01-01

    We report on the development of the vertex detector pixel readout chips based on multi-tier vertically integrated electronics for the International Linear Collider. Some testing results of the VIP2a prototype are presented. The chip is the second iteration of the silicon implementation of the prototype, data-pushed concept of the readout developed at Fermilab. The device was fabricated in the 3D MIT-LL 0.15 {micro}m fully depleted SOI process. The prototype is a three-tier design, featuring 30 x 30 {micro}m{sup 2} pixels, laid out in an array of 48 x 48 pixels.

  13. Monolithic pixel detectors in silicon on insulator technology

    NASA Astrophysics Data System (ADS)

    Bisello, Dario

    2013-05-01

    Silicon On Insulator (SOI) is becoming an attractive technology to fabricate monolithic pixel detectors. The possibility of using the depleted resistive substrate as a drift collection volume and to connect it by means of vias through the buried oxide to the pixel electronic makes this kind of approach interesting both for particle and photon detection. In this paper I report the results obtained in the development of monolithic pixel detectors in an SOI technology by a collaboration between groups from the University and INFN of Padova (Italy) and the LBNL and the SCIPP at UCSC (USA).

  14. High performance uncooled amorphous silicon VGA IRFPA with 17-µm pixel-pitch

    NASA Astrophysics Data System (ADS)

    Tissot, J. L.; Durand, A.; Garret, Th.; Minassian, C.; Robert, P.; Tinnes, S.; Vilain, M.

    2010-04-01

    The high level of accumulated expertise by ULIS and CEA/LETI on uncooled microbolometers made from amorphous silicon enables ULIS to develop VGA IRFPA formats with 17μm pixel-pitch to build up the currently available product catalog. This detector keeps all the innovations developed on the 25 μm pixel-pitch ROIC (detector configuration by serial link, low power consumption and wide electrical dynamic range). The specific appeal of this unit lies in the high spatial resolution it provides. The reduction of the pixel-pitch turns this TEC-less VGA array into a product well adapted for high resolution and compact systems. In the last part of the paper, we will look more closely at the high electro-optical performances of this IRFPA and the rapid performance enhancement. We will insist on NETD trade-off with wide thermal dynamic range, as well as the high characteristics uniformity, achieved thanks to the mastering of the amorphous silicon technology coupled with the ROIC design. This technology node paves the way to high end products as well as low end compact smaller formats like 160 x 120 or smaller.

  15. High-speed readout of high-Z pixel detectors with the LAMBDA detector

    NASA Astrophysics Data System (ADS)

    Pennicard, D.; Smoljanin, S.; Sheviakov, I.; Xia, Q.; Rothkirch, A.; Yu, Y.; Struth, B.; Hirsemann, H.; Graafsma, H.

    2014-12-01

    High-frame-rate X-ray pixel detectors make it possible to perform time-resolved experiments at synchrotron beamlines, and to make better use of these sources by shortening experiment times. LAMBDA is a photon-counting hybrid pixel detector based on the Medipix3 chip, designed to combine a small pixel size of 55 μm, a large tileable module design, high speed, and compatibility with ``high-Z'' sensors for hard X-ray detection. This technical paper focuses on LAMBDA's high-speed-readout functionality, which allows a frame rate of 2000 frames per second with no deadtime between successive images. This takes advantage of the Medipix3 chip's ``continuous read-write'' function and highly parallelised readout. The readout electronics serialise this data and send it back to a server PC over two 10 Gigabit Ethernet links. The server PC controls the detector and receives, processes and stores the data using software designed for the Tango control system. As a demonstration of high-speed readout of a high-Z sensor, a GaAs LAMBDA detector was used to make a high-speed X-ray video of a computer fan.

  16. A germanium hybrid pixel detector with 55μm pixel size and 65,000 channels

    NASA Astrophysics Data System (ADS)

    Pennicard, D.; Struth, B.; Hirsemann, H.; Sarajlic, M.; Smoljanin, S.; Zuvic, M.; Lampert, M. O.; Fritzsch, T.; Rothermund, M.; Graafsma, H.

    2014-12-01

    Hybrid pixel semiconductor detectors provide high performance through a combination of direct detection, a relatively small pixel size, fast readout and sophisticated signal processing circuitry in each pixel. For X-ray detection above 20 keV, high-Z sensor layers rather than silicon are needed to achieve high quantum efficiency, but many high-Z materials such as GaAs and CdTe often suffer from poor material properties or nonuniformities. Germanium is available in large wafers of extremely high quality, making it an appealing option for high-performance hybrid pixel X-ray detectors, but suitable technologies for finely pixelating and bump-bonding germanium have not previously been available. A finely-pixelated germanium photodiode sensor with a 256 by 256 array of 55μm pixels has been produced. The sensor has an n-on-p structure, with 700μm thickness. Using a low-temperature indium bump process, this sensor has been bonded to the Medipix3RX photoncounting readout chip. Tests with the LAMBDA readout system have shown that the detector works successfully, with a high bond yield and higher image uniformity than comparable high-Z systems. During cooling, the system is functional around -80°C (with warmer temperatures resulting in excessive leakage current), with -100°C sufficient for good performance.

  17. Improvement of Event Synchronization in the ATLAS Pixel Readout Development

    NASA Astrophysics Data System (ADS)

    Adams, Logan; Atlas Collaboration

    2017-01-01

    As the LHC continues in Run2, the B-Layer still uses the Atlas-SiROD Pixel readout system initially developed for Run 1. The higher luminosity occurring during Run 2 results in higher occupancy causing increased desynchronization errors in the Pixel Readout. In order to ensure lasting operation of the B-Layer until it is replaced after Run 3, changes were made to the firmware and software to add debug capabilities to identify when the errors are crossing certain thresholds and change the internal control logic accordingly. These features also allow for better debugging of the Event Counter Reset addition to the firmware. This talk will focus on the features implemented and measurements to demonstrate the positive impact on the Pixel DAQ system. A Pixel front-end chip emulator which can be used for readout system development beyond Run 3 will also be discussed. Presenter is Logan Adams, University of Washington.

  18. Pixel-by-pixel VIS/NIR and LIR sensor fusion system

    NASA Astrophysics Data System (ADS)

    Zhang, Evan; Zhang, James S.; Song, Vivian W.; Chin, Ken P.; Hu, Gelbert

    2003-01-01

    Visible (VIS) camera (such as CCD) or Near Infrared (NIR) camera (such as low light level CCD or image intensifier) has high resolution and is easy to distinguish enemy and foe, but it cannot see through thin fog/cloud, heavy smoke/dust, foliage, camouflage, and darkness. The Long Infrared (LIR) imager can overcome above problems, but the resolution is too low and it cannot see the NIR aiming light from enemy. The best solution is to fuse the VIS/NIR and LIR sensors to overcome their shortcomings and take advantages of both sensors. In order to see the same target without parallax, the fusio system must have a common optical aperature. In this paper, three common optical apertures are designed: common reflective objective lens, common beam splitter, and common transmissive objective lens. The first one has very small field of view and the second one needs two heads, so the best choice is the third one, but we must find suitable optical materials and correct the color aberrations from 0.6 to 12 μ. It is a tough job. By choosing ZnSe as the first common piece of the objective lens and using glass for NIR and Ge (or IR glass) for LIR as rest pieces, we only need to and are able to correct the aberrations from 0.6 to 1.0 μ for NIR and from 8 to 12 μ for LIR. Finally, a common reflective objective lens and the common beam splitter are also successfully designed. Five application examples are given. In the digital signal processing, we use only one Altera chip. After inserting data, scaling the image size, and adjusting the signal level, the LIR will have the same format and same pixel number of the VIS/NIR, so real-time pixel-by-pixel sensor fusion is realized. The digital output can be used for further image processing and automatic target recognition, such as if we overlap the LIR image on the VIS/NIR image for missile guidance or rifle sight we don't need to worry about the time and the environment again. A gum-size wireless transmitter is also designed that is

  19. FPIX2, the BTeV pixel readout chip

    SciTech Connect

    David C. Christian et al.

    2003-12-10

    A radiation tolerant pixel readout chip, FPIX2, has been developed at Fermilab for use by BTeV. Some of the requirements of the BTeV pixel readout chip are reviewed and contrasted with requirements for similar devices in LHC experiments. A description of the FPIX2 is given, and results of initial tests of its performance are presented, as is a summary of measurements planned for the coming year.

  20. A Chip and Pixel Qualification Methodology on Imaging Sensors

    NASA Technical Reports Server (NTRS)

    Chen, Yuan; Guertin, Steven M.; Petkov, Mihail; Nguyen, Duc N.; Novak, Frank

    2004-01-01

    This paper presents a qualification methodology on imaging sensors. In addition to overall chip reliability characterization based on sensor s overall figure of merit, such as Dark Rate, Linearity, Dark Current Non-Uniformity, Fixed Pattern Noise and Photon Response Non-Uniformity, a simulation technique is proposed and used to project pixel reliability. The projected pixel reliability is directly related to imaging quality and provides additional sensor reliability information and performance control.

  1. Small pixel CZT detector for hard X-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Wilson, Matthew David; Cernik, Robert; Chen, Henry; Hansson, Conny; Iniewski, Kris; Jones, Lawrence L.; Seller, Paul; Veale, Matthew C.

    2011-10-01

    A new small pixel cadmium zinc telluride (CZT) detector has been developed for hard X-ray spectroscopy. The X-ray performance of four detectors is presented and the detectors are analysed in terms of the energy resolution of each pixel. The detectors were made from CZT crystals grown by the travelling heater method (THM) bonded to a 20×20 application specific integrated circuit (ASIC) and data acquisition (DAQ) system. The detectors had an array of 20×20 pixels on a 250 μm pitch, with each pixel gold-stud bonded to an energy resolving circuit in the ASIC. The DAQ system digitised the ASIC output with 14 bit resolution, performing offset corrections and data storage to disc in real time at up to 40,000 frames per second. The detector geometry and ASIC design was optimised for X-ray spectroscopy up to 150 keV and made use of the small pixel effect to preferentially measure the electron signal. A 241Am source was used to measure the spectroscopic performance and uniformity of the detectors. The average energy resolution (FWHM at 59.54 keV) of each pixel ranged from 1.09±0.46 to 1.50±0.57 keV across the four detectors. The detectors showed good spectral performance and uniform response over almost all pixels in the 20×20 array. A large area 80×80 pixel detector will be built that will utilise the scalable design of the ASIC and the large areas of monolithic spectroscopic grade THM grown CZT that are now available. The large area detector will have the same performance as that demonstrated here.

  2. High-voltage pixel sensors for ATLAS upgrade

    NASA Astrophysics Data System (ADS)

    Perić, I.; Kreidl, C.; Fischer, P.; Bompard, F.; Breugnon, P.; Clemens, J.-C.; Fougeron, D.; Liu, J.; Pangaud, P.; Rozanov, A.; Barbero, M.; Feigl, S.; Capeans, M.; Ferrere, D.; Pernegger, H.; Ristic, B.; Muenstermann, D.; Gonzalez Sevilla, S.; La Rosa, A.; Miucci, A.; Nessi, M.; Iacobucci, G.; Backhaus, M.; Hügging, Fabian; Krüger, H.; Hemperek, T.; Obermann, T.; Wermes, N.; Garcia-Sciveres, M.; Quadt, A.; Weingarten, J.; George, M.; Grosse-Knetter, J.; Rieger, J.; Bates, R.; Blue, A.; Buttar, C.; Hynds, D.

    2014-11-01

    The high-voltage (HV-) CMOS pixel sensors offer several good properties: a fast charge collection by drift, the possibility to implement relatively complex CMOS in-pixel electronics and the compatibility with commercial processes. The sensor element is a deep n-well diode in a p-type substrate. The n-well contains CMOS pixel electronics. The main charge collection mechanism is drift in a shallow, high field region, which leads to a fast charge collection and a high radiation tolerance. We are currently evaluating the use of the high-voltage detectors implemented in 180 nm HV-CMOS technology for the high-luminosity ATLAS upgrade. Our approach is replacing the existing pixel and strip sensors with the CMOS sensors while keeping the presently used readout ASICs. By intelligence we mean the ability of the sensor to recognize a particle hit and generate the address information. In this way we could benefit from the advantages of the HV sensor technology such as lower cost, lower mass, lower operating voltage, smaller pitch, smaller clusters at high incidence angles. Additionally we expect to achieve a radiation hardness necessary for ATLAS upgrade. In order to test the concept, we have designed two HV-CMOS prototypes that can be readout in two ways: using pixel and strip readout chips. In the case of the pixel readout, the connection between HV-CMOS sensor and the readout ASIC can be established capacitively.

  3. Error-free demodulation of pixelated carrier frequency interferograms.

    PubMed

    Servin, M; Estrada, J C

    2010-08-16

    Recently, pixelated spatial carrier interferograms have been used in optical metrology and are an industry standard nowadays. The main feature of these interferometers is that each pixel over the video camera may be phase-modulated by any (however fixed) desired angle within [0,2pi] radians. The phase at each pixel is shifted without cross-talking from their immediate neighborhoods. This has opened new possibilities for experimental spatial wavefront modulation not dreamed before, because we are no longer constrained to introduce a spatial-carrier using a tilted plane. Any useful mathematical model to phase-modulate the testing wavefront in a pixel-wise basis can be used. However we are nowadays faced with the problem that these pixelated interferograms have not been correctly demodulated to obtain an error-free (exact) wavefront estimation. The purpose of this paper is to offer the general theory that allows one to demodulate, in an exact way, pixelated spatial-carrier interferograms modulated by any thinkable two-dimensional phase carrier.

  4. Techniques for precise energy calibration of particle pixel detectors

    NASA Astrophysics Data System (ADS)

    Kroupa, M.; Campbell-Ricketts, T.; Bahadori, A.; Empl, A.

    2017-03-01

    We demonstrate techniques to improve the accuracy of the energy calibration of Timepix pixel detectors, used for the measurement of energetic particles. The typical signal from such particles spreads among many pixels due to charge sharing effects. As a consequence, the deposited energy in each pixel cannot be reconstructed unless the detector is calibrated, limiting the usability of such signals for calibration. To avoid this shortcoming, we calibrate using low energy X-rays. However, charge sharing effects still occur, resulting in part of the energy being deposited in adjacent pixels and possibly lost. This systematic error in the calibration process results in an error of about 5% in the energy measurements of calibrated devices. We use FLUKA simulations to assess the magnitude of charge sharing effects, allowing a corrected energy calibration to be performed on several Timepix pixel detectors and resulting in substantial improvement in energy deposition measurements. Next, we address shortcomings in calibration associated with the huge range (from kiloelectron-volts to megaelectron-volts) of energy deposited per pixel which result in a nonlinear energy response over the full range. We introduce a new method to characterize the non-linear response of the Timepix detectors at high input energies. We demonstrate improvement using a broad range of particle types and energies, showing that the new method reduces the energy measurement errors, in some cases by more than 90%.

  5. Challenges of small-pixel infrared detectors: a review

    NASA Astrophysics Data System (ADS)

    Rogalski, A.; Martyniuk, P.; Kopytko, M.

    2016-04-01

    In the last two decades, several new concepts for improving the performance of infrared detectors have been proposed. These new concepts particularly address the drive towards the so-called high operating temperature focal plane arrays (FPAs), aiming to increase detector operating temperatures, and as a consequence reduce the cost of infrared systems. In imaging systems with the above megapixel formats, pixel dimension plays a crucial role in determining critical system attributes such as system size, weight and power consumption (SWaP). The advent of smaller pixels has also resulted in the superior spatial and temperature resolution of these systems. Optimum pixel dimensions are limited by diffraction effects from the aperture, and are in turn wavelength-dependent. In this paper, the key challenges in realizing optimum pixel dimensions in FPA design including dark current, pixel hybridization, pixel delineation, and unit cell readout capacity are outlined to achieve a sufficiently adequate modulation transfer function for the ultra-small pitches involved. Both photon and thermal detectors have been considered. Concerning infrared photon detectors, the trade-offs between two types of competing technology—HgCdTe material systems and III-V materials (mainly barrier detectors)—have been investigated.

  6. Fault tolerant photodiode and photogate active pixel sensors

    NASA Astrophysics Data System (ADS)

    Jung, Cory; Chapman, Glenn H.; La Haye, Michelle L.; Djaja, Sunjaya; Cheung, Desmond Y. H.; Lin, Henry; Loo, Edward; Audet, Yves R.

    2005-03-01

    As the pixel counts of digital imagers increase, the challenge of maintaining high yields and ensuring reliability over an imager"s lifetime increases. A fault tolerant active pixel sensor (APS) has been designed to meet this need by splitting an APS in half and operating both halves in parallel. The fault tolerant APS will perform normally in the no defect case and will produce approximately half the output for single defects. Thus, the entire signal can be recovered by multiplying the output by two. Since pixels containing multiple defects are rare, this design can correct for most defects allowing for higher production yields. Fault tolerant photodiode and photogate APS" were fabricated in 0.18-micron technology. Testing showed that the photodiode APS could correct for optically induced and electrically induced faults, within experimental error. The photogate APS was only tested for optically induced defects and also corrects for defects within experimental error. Further testing showed that the sensitivity of fault tolerant pixels was approximately 2-3 times more sensitive than the normal pixels. HSpice simulations of the fault tolerant APS circuit did not show increased sensitivity, however an equivalent normal APS circuit with twice width readout and row transistors was 1.90 times more sensitive than a normal pixel.

  7. Frequency distribution signatures and classification of within-object pixels

    PubMed Central

    Stow, Douglas A.; Toure, Sory I.; Lippitt, Christopher D.; Lippitt, Caitlin L.; Lee, Chung-rui

    2011-01-01

    The premise of geographic object-based image analysis (GEOBIA) is that image objects are composed of aggregates of pixels that correspond to earth surface features of interest. Most commonly, image-derived objects (segments) or objects associated with predefined land units (e.g., agricultural fields) are classified using parametric statistical characteristics (e.g., mean and standard deviation) of the within-object pixels. The objective of this exploratory study was to examine the between- and within-class variability of frequency distributions of multispectral pixel values, and to evaluate a quantitative measure and classification rule that exploits the full pixel frequency distribution of within object pixels (i.e., histogram signatures) compared to simple parametric statistical characteristics. High spatial resolution Quickbird satellite multispectral data of Accra, Ghana were evaluated in the context of mapping land cover and land use and socioeconomic status. Results show that image objects associated with land cover and land use types can have characteristic, non-normal frequency distributions (histograms). Signatures of most image objects tended to match closely the training signature of a single class or sub-class. Curve matching approaches to classifying multi-pixel frequency distributions were found to be slightly more effective than standard statistical classifiers based on a nearest neighbor classifier. PMID:22408575

  8. COMBINE*: An integrated opto-mechanical tool for laser performance modeling

    NASA Astrophysics Data System (ADS)

    Rehak, M.; Di Nicola, J. M.

    2015-02-01

    Accurate modeling of thermal, mechanical and optical processes is important for achieving reliable, high-performance high energy lasers such as those at the National Ignition Facility [1] (NIF). The need for this capability is even more critical for high average power, high repetition rate applications. Modeling the effects of stresses and temperature fields on optical properties allows for optimal design of optical components and more generally of the architecture of the laser system itself. Stresses change the indices of refractions and induce inhomogeneities and anisotropy. We present a modern, integrated analysis tool that efficiently produces reliable results that are used in our laser propagation tools such as VBL [5]. COMBINE is built on and supplants the existing legacy tools developed for the previous generations of lasers at LLNL but also uses commercially available mechanical finite element codes ANSYS or COMSOL (including computational fluid dynamics). The COMBINE code computes birefringence and wave front distortions due to mechanical stresses on lenses and slabs of arbitrary geometry. The stresses calculated typically originate from mounting support, vacuum load, gravity, heat absorption and/or attending cooling. Of particular importance are the depolarization and detuning effects of nonlinear crystals due to thermal loading. Results are given in the form of Jones matrices, depolarization maps and wave front distributions. An incremental evaluation of Jones matrices and ray propagation in a 3D mesh with a stress and temperature field is performed. Wavefront and depolarization maps are available at the optical aperture and at slices within the optical element. The suite is validated, user friendly, supported, documented and amenable to collaborative development. * COMBINE stands for Code for Opto-Mechanical Birefringence Integrated Numerical Evaluations.

  9. A dynamic opto-physiological model to effectively interpret retinal microvascular circulation

    NASA Astrophysics Data System (ADS)

    Hassan, Harnani; Hu, Sijung; Dwyer, Vincent M.

    2015-03-01

    The demand of non-invasive ocular screening is rapidly growing due to an increase of age related eye diseases worldwide. An indeed in-depth understanding of optical properties is required to elucidate nature of retinal tissue. The research aims to investigate an effective biomedical engineering approach to allow process region of interests (ROIs) in eyes to reveal physiological status. A dynamic opto-physiological model (DOPM) representing retinal microvascular circulation underlying a diffusion approximation to solve radiative transport theorem (RTT) has being developed to interpret patho-physiological phenomena. DOPM is being applied in imaging photoplethysmography (iPPG) to extract PPG signals from a series of 2D matrix images to access blood perfusion and oxygen saturation distributions. A variation of microvascular circulation could be mapped for an effectively diagnostic screening. The work presents mathematical modelling based ten layers of ocular tissue tested with four set of controlled parameters demontrated detection ratio between normal tissue damage or abnormal tissue and significant change of AC signal amplitude in these tissues. The result shows signicant change of AC signal amplitude in abnormal tissue. The preliminary results show extractable PPG signals from eye fundus video; experimented at five ROIs: whole fundus, optical disk, main vein vessel, lesion area and affected area. The outcome shows optical disk region gave a better performance compared to whole fundus region and main vein vessel. The robustness, miniaturization and artefact reduction capability of DOPM to discriminate oxygenation levels in retina could offer a new insight to access retinal patho-physiological status.

  10. A 6 D.O.F. opto-inertial tracker for virtual reality experiments in microgravity.

    PubMed

    Zaoui, M; Wormell, D; Altshuler, Y; Foxlin, E; McIntyre, J

    2001-01-01

    Gravity plays a role in many different levels of human motor behavior. It dictates the laws of motion of our body and limbs, as well as of the objects in the external world with which we wish to interact. The dynamic interaction of our body with the world is molded within gravity's constraints. The role played by gravity in the perception of visual stimuli and the elaboration of human movement is an active research theme in the field of Neurophysiology. Conditions of microgravity, coupled with techniques from the world of virtual reality, provide a unique opportunity to address these questions concerning the function of the human sensorimotor system. The ability to measure movements of the head and to update in real time the visual scene presented to the subject based on these measurements is a key element in producing a realistic virtual environment. A variety of head-tracking hardware exists on the market today, but none seem particularly well suited to the constraints of working with a space station environment. Nor can any of the existing commercial systems meet the more stringent requirements for physiological experimentation (high accuracy, high resolution, low jitter, low lag) in a wireless configuration. To this end, we have developed and tested a hybrid opto-inertial 6 degree-of-freedom tracker based on existing inertial technology. To confirm that the inertial components and algorithms will function properly, this system was tested in the microgravity conditions of parabolic flight. Here we present the design goals of this tracker, the system configuration and the results of 0g and 1g testing.

  11. A 6 D.O.F. opto-inertial tracker for virtual reality experiments in microgravity

    NASA Astrophysics Data System (ADS)

    Zaoui, Mohamed; Wormell, Dean; Altshuler, Yury; Foxlin, Eric; McIntyre, Joseph

    2001-08-01

    Gravity plays a role in many different levels of human motor behavior. It dictates the laws of motion of our body and limbs, as well as of the objects in the external world with which we wish to interact. The dynamic interaction of our body with the world is molded within gravity's constraints. The role played by gravity in the perception of visual stimuli and the elaboration of human movement is an active research theme in the field of Neurophysiology. Conditions of microgravity, coupled with techniques from the world of virtual reality, provide a unique opportunity to address these questions concerning the function of the human sensorimotor system [1]. The ability to measure movements of the head and to update in real time the visual scene presented to the subject based on these measurements is a key element in producing a realistic virtual environment. A variety of head-tracking hardware exists on the market today [2-4], but none seem particularly well suited to the constraints of working with a space station environment. Nor can any of the existing commercial systems meet the more stringent requirements for physiological experimentation (high accuracy, high resolution, low jitter, low lag) in a wireless configuration. To this end, we have developed and tested a hybrid opto-inertial 6 degree-of-freedom tracker based on existing inertial technology [5-8]. To confirm that the inertial components and algorithms will function properly, this system was tested in the microgravity conditions of parabolic flight. Here we present the design goals of this tracker, the system configuration and the results of 0g and 1g testing.

  12. Opto-mechanical design for transmission optics in cryogenic IR instrumentation

    NASA Astrophysics Data System (ADS)

    Kroes, Gabby; Kragt, Jan, II; Navarro, Ramon; Elswijk, Eddy; Hanenburg, Hiddo

    2008-07-01

    ASTRON is involved in the development and realization of various optical astronomical instruments for ground-based as well as space telescopes, with a focus on near- and mid-infrared instrumentation. ASTRON has developed, among others, cryogenic optics for the first generation ESO VLT and VLTI instruments VISIR, MIDI and the SPIFFI 2K-camera for SINFONI. Currently under construction are MIRI for the James Webb Space Telescope and X-shooter for the second generation ESO VLT instrumentation, while the initial design of several ELT instruments has started. Mounting optics is always a compromise between firmly fixing the optics and preventing stresses within the optics. The fixing should ensure mechanical stability and thus accurate positioning in various gravity orientations, temperature ranges, during launch, transport or earthquake. On the other hand, the fixings can induce deformations and sometimes birefringence in the optics and thus cause optical errors. Even cracking or breaking of the optics is a risk, especially at the cryogenic temperatures required in instruments for infrared astronomy, where differential expansion of various materials amounts easily to several millimetres per meter. Special kinematic mounts are therefore needed to ensure both accurate positioning and low stress. Though ASTRON is involved in the full realization of instruments from initial design to commissioning, this paper concentrates on the opto-mechanical design of optics mountings, especially for large transmission optics in cryogenic circumstances. It describes the development of temperature-invariant ("a-thermal"), kinematic designs and how they are implemented in instruments such as SPIFFI and X-shooter.

  13. Thermally evaporated mechanically hard tin oxide thin films for opto-electronic apllications

    SciTech Connect

    Tripathy, Sumanta K.; Rajeswari, V. P.

    2014-01-28

    Tungsten doped tin oxide (WTO) and Molybdenum doped tin oxide (MoTO) thin film were deposited on corn glass by thermal evaporation method. The films were annealed at 350°C for one hour. Structural analysis using Xray diffraction data shows both the films are polycrystalline in nature with monoclinic structure of tin oxide, Sn{sub 3}O{sub 4}, corresponding to JCPDS card number 01-078-6064. SEM photograph showed that both the films have spherical grains with size in the range of 20–30 nm. Compositional analysis was carried out using EDS which reveals the presence of Sn, O and the dopant Mo/W only thereby indicating the absence of any secondary phase in the films. The films are found to contain nearly 6 wt% of Mo, 8 wt% of W as dopants respectively. The transmission pattern for both the films in the spectral range 200 – 2000 nm shows that W doping gives a transparency of nearly 80% from 380 nm onwards while Mo doping has less transparency of 39% at 380nm. Film hardness measurement using Triboscope shows a film hardness of about 9–10 GPa for both the films. It indicates that W or M doping in tin oxide provides the films the added advantage of withstanding the mechanical wear and tear due to environmental fluctuations By optimizing the optical and electrical properties, W/Mo doped tin oxide films may be explored as window layers in opto-electronic applications such as solar cells.

  14. Development of optics with micro-LED arrays for improved opto-electronic neural stimulation

    NASA Astrophysics Data System (ADS)

    Chaudet, Lionel; Neil, Mark; Degenaar, Patrick; Mehran, Kamyar; Berlinguer-Palmini, Rolando; Corbet, Brian; Maaskant, Pleun; Rogerson, David; Lanigan, Peter; Bamberg, Ernst; Roska, Botond

    2013-03-01

    The breakthrough discovery of a nanoscale optically gated ion channel protein, Channelrhodopsin 2 (ChR2), and its combination with a genetically expressed ion pump, Halorhodopsin, allowed the direct stimulation and inhibition of individual action potentials with light alone. This work reports developments of ultra-bright elec­ tronically controlled optical array sources with enhanced light gated ion channels and pumps for use in systems to further our understanding of both brain and visual function. This work is undertaken as part of the European project, OptoNeuro. Micro-LED arrays permit spatio-temporal control of neuron stimulation on sub-millisecond timescales. However they are disadvantaged by their broad spatial light emission distribution and low fill factor. We present the design and implementation of a projection and micro-optics system for use with a micro-LED array consisting of a 16x16 matrix of 25 μm diameter micro-LEDs with 150 μm centre-to-centre spacing and an emission spectrum centred at 470 nm overlapping the peak sensitivity of ChR2 and its testing on biological samples. The projection system images the micro-LED array onto micro-optics to improve the fill-factor from ~2% to more than 78% by capturing a larger fraction of the LED emission and directing it correctly to the sample plane. This approach allows low fill factor arrays to be used effectively, which in turn has benefits in terms of thermal management and electrical drive from CMOS backplane electronics. The entire projection system is integrated into a microscope prototype to provide stimulation spots at the same size as the neuron cell body (μ10 pm).

  15. Organic polymer-metal nano-composites for opto-electronic sensing of chemicals in agriculture

    NASA Astrophysics Data System (ADS)

    Sarkisov, Sergey S.; Czarick, Michael; Fairchild, Brian D.; Liang, Yi; Kukhtareva, Tatiana; Curley, Michael J.

    2013-03-01

    Recent research findings led the team to conclude that a long lasting and inexpensive colorimetric sensor for monitoring ammonia emission from manure in confined animal feeding operations could eventually become feasible. The sensor uses robust method of opto-electronic spectroscopic measurement of the reversible change of the color of a sensitive nano-composite reagent film in response to ammonia. The film is made of a metal (gold, platinum, or palladium) nano-colloid in a polymer matrix with an ammonia-sensitive indicator dye additive. The response of the indicator dye (increase of the optical absorption in the region 550 to 650 nm) is enhanced by the nano-particles (~10 nm in size) in two ways: (a) concentration of the optical field near the nano-particle due to the plasmon resonance; and (b) catalytic acceleration of the chemical reaction of deprotonization of the indicator dye in the presence of ammonia and water vapor. This enhancement helps to make a miniature and rugged sensing element without compromising its sensitivity of less than 1 ppm for the range 0 to 100 ppm. The sensor underwent field tests in commercial broiler farms in Georgia, Alabama, and Arkansas and was compared against a commercial photoacoustic gas analyzer. The sensor output correlated well with the data from the photoacoustic analyzer (correlation coefficient not less than 0.9 and the linear regression slope after calibration close to 1.0) for several weeks of continuous operation. The sources of errors were analyzed and the conclusions on the necessary improvements and the potential use of the proposed device were made.

  16. Active pixel sensor having intra-pixel charge transfer with analog-to-digital converter

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra K. (Inventor); Pain, Bedabrata (Inventor); Nixon, Robert H. (Inventor); Zhou, Zhimin (Inventor)

    2003-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node and an analog-to-digital converter formed in the substrate connected to the output of the readout circuit.

  17. Active pixel sensor having intra-pixel charge transfer with analog-to-digital converter

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra K. (Inventor); Pain, Bedabrata (Inventor); Nixon, Robert H. (Inventor); Zhou, Zhimin (Inventor)

    2000-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor Integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node and an analog-to-digital converter formed in the substrate connected to the output of the readout circuit.

  18. Characterizing opto-electret based paper speakers by using a real-time projection Moiré metrology system

    NASA Astrophysics Data System (ADS)

    Chang, Ya-Ling; Hsu, Kuan-Yu; Lee, Chih-Kung

    2016-03-01

    Advancement of distributed piezo-electret sensors and actuators facilitates various smart systems development, which include paper speakers, opto-piezo/electret bio-chips, etc. The array-based loudspeaker system possess several advantages over conventional coil speakers, such as light-weightness, flexibility, low power consumption, directivity, etc. With the understanding that the performance of the large-area piezo-electret loudspeakers or even the microfluidic biochip transport behavior could be tailored by changing their dynamic behaviors, a full-field real-time high-resolution non-contact metrology system was developed. In this paper, influence of the resonance modes and the transient vibrations of an arraybased loudspeaker system on the acoustic effect were measured by using a real-time projection moiré metrology system and microphones. To make the paper speaker even more versatile, we combine the photosensitive material TiOPc into the original electret loudspeaker. The vibration of this newly developed opto-electret loudspeaker could be manipulated by illuminating different light-intensity patterns. Trying to facilitate the tailoring process of the opto-electret loudspeaker, projection moiré was adopted to measure its vibration. By recording the projected fringes which are modulated by the contours of the testing sample, the phase unwrapping algorithm can give us a continuous phase distribution which is proportional to the object height variations. With the aid of the projection moiré metrology system, the vibrations associated with each distinctive light pattern could be characterized. Therefore, we expect that the overall acoustic performance could be improved by finding the suitable illuminating patterns. In this manuscript, the system performance of the projection moiré and the optoelectret paper speakers were cross-examined and verified by the experimental results obtained.

  19. Clinical feasibility study of combined opto-acoustic and ultrasonic imaging modality providing coregistered functional and anatomical maps of breast tumors

    NASA Astrophysics Data System (ADS)

    Zalev, Jason; Clingman, Bryan; Smith, Remie J.; Herzog, Don; Miller, Tom; Stavros, A. Thomas; Ermilov, Sergey; Conjusteau, André; Tsyboulski, Dmitri; Oraevsky, Alexander A.; Kist, Kenneth; Dornbluth, N. C.; Otto, Pamela

    2013-03-01

    We report on findings from the clinical feasibility study of the ImagioTM. Breast Imaging System, which acquires two-dimensional opto-acoustic (OA) images co-registered with conventional ultrasound using a specialized duplex hand-held probe. Dual-wavelength opto-acoustic technology is used to generate parametric maps based upon total hemoglobin and its oxygen saturation in breast tissues. This may provide functional diagnostic information pertaining to tumor metabolism and microvasculature, which is complementary to morphological information obtained with conventional gray-scale ultrasound. We present co-registered opto-acoustic and ultrasonic images of malignant and benign tumors from a recent clinical feasibility study. The clinical results illustrate that the technology may have the capability to improve the efficacy of breast tumor diagnosis. In doing so, it may have the potential to reduce biopsies and to characterize cancers that were not seen well with conventional gray-scale ultrasound alone.

  20. Design of 10Gbps optical encoder/decoder structure for FE-OCDMA system using SOA and opto-VLSI processors.

    PubMed

    Aljada, Muhsen; Hwang, Seow; Alameh, Kamal

    2008-01-21

    In this paper we propose and experimentally demonstrate a reconfigurable 10Gbps frequency-encoded (1D) encoder/decoder structure for optical code division multiple access (OCDMA). The encoder is constructed using a single semiconductor optical amplifier (SOA) and 1D reflective Opto-VLSI processor. The SOA generates broadband amplified spontaneous emission that is dynamically sliced using digital phase holograms loaded onto the Opto-VLSI processor to generate 1D codewords. The selected wavelengths are injected back into the same SOA for amplifications. The decoder is constructed using single Opto-VLSI processor only. The encoded signal can successfully be retrieved at the decoder side only when the digital phase holograms of the encoder and the decoder are matched. The system performance is measured in terms of the auto-correlation and cross-correlation functions as well as the eye diagram.

  1. Opto-electro-modulated transient photovoltage and photocurrent system for investigation of charge transport and recombination in solar cells.

    PubMed

    Shi, Jiangjian; Li, Dongmei; Luo, Yanhong; Wu, Huijue; Meng, Qingbo

    2016-12-01

    An opto-electro-modulated transient photovoltage/photocurrent system has been developed to probe microscopic charge processes of a solar cell in its adjustable operating conditions. The reliability of this system is carefully determined by electric circuit simulations and experimental measurements. Using this system, the charge transport, recombination and storage properties of a conventional multicrystalline silicon solar cell under different steady-state bias voltages, and light illumination intensities are investigated. This system has also been applied to study the influence of the hole transport material layer on charge extraction and the microscopic charge processes behind the widely considered photoelectric hysteresis in perovskite solar cells.

  2. Opto-electro-modulated transient photovoltage and photocurrent system for investigation of charge transport and recombination in solar cells

    NASA Astrophysics Data System (ADS)

    Shi, Jiangjian; Li, Dongmei; Luo, Yanhong; Wu, Huijue; Meng, Qingbo

    2016-12-01

    An opto-electro-modulated transient photovoltage/photocurrent system has been developed to probe microscopic charge processes of a solar cell in its adjustable operating conditions. The reliability of this system is carefully determined by electric circuit simulations and experimental measurements. Using this system, the charge transport, recombination and storage properties of a conventional multicrystalline silicon solar cell under different steady-state bias voltages, and light illumination intensities are investigated. This system has also been applied to study the influence of the hole transport material layer on charge extraction and the microscopic charge processes behind the widely considered photoelectric hysteresis in perovskite solar cells.

  3. Optics and cryogenics for the 1.1 THz multi-pixel heterodyne receiver for APEX

    NASA Astrophysics Data System (ADS)

    Hurtado, Norma; Graf, Urs U.; Adams, Henning; Honingh, C. E.; Jacobs, Karl; Pütz, Patrick; Güsten, Rolf; Stutzki, Jürgen

    2014-08-01

    The 1.1 THz multi-pixel heterodyne receiver will be mounted in the Nasmyth A cabin of the 12 m APEX telescope on the Chajnantor plateau, 5000 meters altitude in northern Chile. The receiver will cover the spectral window of 1000 - 1080 GHz, where important spectral lines like CO 9-8 at 1036.9 GHz, a tracer of warm and dense gas and OH+ at 1033 GHz and NH+ at 1012.6 GHz, both important for the study of chemical networks in the ISM, are located. The multi-pixel receiver greatly enhances the science output under the difficult observing conditions in this frequency range. Two 9-pixel focal plane sub-arrays on orthogonal polarizations are installed in easily removable cartridges. We developed a new thermal link to connect the cartridges to the cryostat. Our thermal link is an all-metal design: aluminum and Invar. All the optics is fully reflective, thus avoiding the absorption and reflection losses of dielectric lenses and reducing standing waves in the receiver. To guaranty internal optics alignment, we employ a monolithic integrated optics approach for the cold optics and the Focal Plane Unit (FPU) optics modeled after the CHARM (Compact Heterodyne Array Receiver Module) concept. The receiver uses synthesizer-driven solid-state local oscillators (LO) and the mixers will be balanced SIS mixers, which are essentially based on the design of the on-chip balanced SIS mixers at 490 GHz developed in our institute. Singleended HEB mixers are used for the laboratory tests of the optics. The LO power distribution is accommodated behind the FPU optics. It is composed of the LO optics, which includes a collimating Fourier grating, and an LO distribution plate to supply LO signal to each of the 9 pixels of the sub-array. Different options for the LO coupling design and fabrication are being analyzed and will be based on in-house hybrid waveguide/planar technology. We summarize the receiver project with emphasis on the cryogenics and the optics and present laboratory test results

  4. CMOS in-pixel optical pulse frequency modulator

    NASA Astrophysics Data System (ADS)

    Nel, Nicolaas E.; du Plessis, M.; Joubert, T.-H.

    2016-02-01

    This paper covers the design of a complementary metal oxide semiconductor (CMOS) pixel readout circuit with a built-in frequency conversion feature. The pixel contains a CMOS photo sensor along with all signal-to-frequency conversion circuitry. An 8×8 array of these pixels is also designed. Current imaging arrays often use analog-to-digital conversion (ADC) and digital signal processing (DSP) techniques that are off-chip1. The frequency modulation technique investigated in this paper is preferred over other ADC techniques due to its smaller size, and the possibility of a higher dynamic range. Careful considerations are made regarding the size of the components of the pixel, as various characteristics of CMOS devices are limited by decreasing the scale of the components2. The methodology used was the CMOS design cycle for integrated circuit design. All components of the pixel were designed from first principles to meet necessary requirements of a small pixel size (30×30 μm2) and an output resolution greater than that of an 8-bit ADC. For the photodetector, an n+-p+/p-substrate diode was designed with a parasitic capacitance of 3 fF. The analog front-end stage was designed around a Schmitt trigger circuit. The photo current is integrated on an integration capacitor of 200 fF, which is reset when the Schmitt trigger output voltage exceeds a preset threshold. The circuit schematic and layout were designed using Cadence Virtuoso and the process used was the AMS CMOS 350 nm process using a power supply of 5V. The simulation results were confirmed to comply with specifications, and the layout passed all verification checks. The dynamic range achieved is 58.828 dB per pixel, with the output frequencies ranging from 12.341kHz to 10.783 MHz. It is also confirmed that the output frequency has a linear relationship to the photocurrent generated by the photodiode.

  5. VeloPix: the pixel ASIC for the LHCb upgrade

    NASA Astrophysics Data System (ADS)

    Poikela, T.; De Gaspari, M.; Plosila, J.; Westerlund, T.; Ballabriga, R.; Buytaert, J.; Campbell, M.; Llopart, X.; Wyllie, K.; Gromov, V.; van Beuzekom, M.; Zivkovic, V.

    2015-01-01

    The LHCb Vertex Detector (VELO) will be upgraded in 2018 along with the other subsystems of LHCb in order to enable full readout at 40 MHz, with the data fed directly to the software triggering algorithms. The upgraded VELO is a lightweight hybrid pixel detector operating in vacuum in close proximity to the LHC beams. The readout will be provided by a dedicated front-end ASIC, dubbed VeloPix, matched to the LHCb readout requirements and the 55 × 55 μm VELO pixel dimensions. The chip is closely related to the Timepix3, from the Medipix family of ASICs. The principal challenge that the chip has to meet is a hit rate of up to 900 Mhits/s, resulting in a required output bandwidth of more than 16 Gbit/s. The occupancy across the chip is also very non-uniform, and the radiation levels reach an integrated 400 Mrad over the lifetime of the detector.VeloPix is a binary pixel readout chip with a data driven readout, designed in 130 nm CMOS technology. The pixels are combined into groups of 2 × 4 super pixels, enabling a shared logic and a reduction of bandwidth due to combined address and time stamp information. The pixel hits are combined with other simultaneous hits in the same super pixel, time stamped, and immediately driven off-chip. The analog front-end must be sufficiently fast to accurately time stamp the data, with a small enough dead time to minimize data loss in the most occupied regions of the chip. The data is driven off chip with a custom designed high speed serialiser. The current status of the ASIC design, the chip architecture and the simulations will be described.

  6. Pixel Analysis of Photospheric Spectral Data. I. Plasma Dynamics

    NASA Astrophysics Data System (ADS)

    Rasca, Anthony P.; Chen, James; Pevtsov, Alexei A.

    2016-11-01

    Recent observations of the photosphere using high spatial and temporal resolution show small dynamic features at or below the current resolving limits. A new pixel dynamics method has been developed to analyze spectral profiles and quantify changes in line displacement, width, asymmetry, and peakedness of photospheric absorption lines. The algorithm evaluates variations of line profile properties in each pixel and determines the statistics of such fluctuations averaged over all pixels in a given region. The method has been used to derive statistical characteristics of pixel fluctuations in observed quiet-Sun regions, an active region with no eruption, and an active region with an ongoing eruption. Using Stokes I images from the Vector Spectromagnetograph (VSM) of the Synoptic Optical Long-term Investigations of the Sun (SOLIS) telescope on 2012 March 13, variations in line width and peakedness of Fe i 6301.5 Å are shown to have a distinct spatial and temporal relationship with an M7.9 X-ray flare in NOAA 11429. This relationship is observed as stationary and contiguous patches of pixels adjacent to a sunspot exhibiting intense flattening in the line profile and line-center displacement as the X-ray flare approaches peak intensity, which is not present in area scans of the non-eruptive active region. The analysis of pixel dynamics allows one to extract quantitative information on differences in plasma dynamics on sub-pixel scales in these photospheric regions. The analysis can be extended to include the Stokes parameters and study signatures of vector components of magnetic fields and coupled plasma properties.

  7. Visual mining business service using pixel bar charts

    NASA Astrophysics Data System (ADS)

    Hao, Ming C.; Dayal, Umeshwar; Casati, Fabio

    2004-06-01

    Basic bar charts have been commonly available, but they only show highly aggregated data. Finding the valuable information hidden in the data is essential to the success of business. We describe a new visualization technique called pixel bar charts, which are derived from regular bar charts. The basic idea of a pixel bar chart is to present all data values directly instead of aggregating them into a few data values. Pixel bar charts provide data distribution and exceptions besides aggregated data. The approach is to represent each data item (e.g. a business transaction) by a single pixel in the bar chart. The attribute of each data item is encoded into the pixel color and can be accessed and drilled down to the detail information as needed. Different color mappings are used to represent multiple attributes. This technique has been prototyped in three business service applications-Business Operation Analysis, Sales Analysis, and Service Level Agreement Analysis at Hewlett Packard Laboratories. Our applications show the wide applicability and usefulness of this new idea.

  8. The pixel tracking telescope at the Fermilab Test Beam Facility

    SciTech Connect

    Kwan, Simon; Lei, CM; Menasce, Dario; Moroni, Luigi; Ngadiuba, Jennifer; Prosser, Alan; Rivera, Ryan; Terzo, Stefano; Turqueti, Marcos; Uplegger, Lorenzo; Vigani, Luigi; Dinardo, Mauro E.

    2016-03-01

    An all silicon pixel telescope has been assembled and used at the Fermilab Test Beam Facility (FTBF) since 2009 to provide precise tracking information for different test beam experiments with a wide range of Detectors Under Test (DUTs) requiring high resolution measurement of the track impact point. The telescope is based on CMS pixel modules left over from the CMS forward pixel production. Eight planes are arranged to achieve a resolution of less than 8 μm on the 120 GeV proton beam transverse coordinate at the DUT position. In order to achieve such resolution with 100 × 150 μm2 pixel cells, the planes were tilted to 25 degrees to maximize charge sharing between pixels. Crucial for obtaining this performance is the alignment software, called Monicelli, specifically designed and optimized for this system. This paper will describe the telescope hardware, the data acquisition system and the alignment software constituting this particle tracking system for test beam users.

  9. Super pixel density based clustering automatic image classification method

    NASA Astrophysics Data System (ADS)

    Xu, Mingxing; Zhang, Chuan; Zhang, Tianxu

    2015-12-01

    The image classification is an important means of image segmentation and data mining, how to achieve rapid automated image classification has been the focus of research. In this paper, based on the super pixel density of cluster centers algorithm for automatic image classification and identify outlier. The use of the image pixel location coordinates and gray value computing density and distance, to achieve automatic image classification and outlier extraction. Due to the increased pixel dramatically increase the computational complexity, consider the method of ultra-pixel image preprocessing, divided into a small number of super-pixel sub-blocks after the density and distance calculations, while the design of a normalized density and distance discrimination law, to achieve automatic classification and clustering center selection, whereby the image automatically classify and identify outlier. After a lot of experiments, our method does not require human intervention, can automatically categorize images computing speed than the density clustering algorithm, the image can be effectively automated classification and outlier extraction.

  10. Pixel-feature hybrid fusion for PET/CT images.

    PubMed

    Zhu, Yang-Ming; Nortmann, Charles A

    2011-02-01

    Color blending is a popular display method for functional and anatomic image fusion. The underlay image is typically displayed in grayscale, and the overlay image is displayed in pseudo colors. This pixel-level fusion provides too much information for reviewers to analyze quickly and effectively and clutters the display. To improve the fusion image reviewing speed and reduce the information clutter, a pixel-feature hybrid fusion method is proposed and tested for PET/CT images. Segments of the colormap are selectively masked to have a few discrete colors, and pixels displayed in the masked colors are made transparent. The colormap thus creates a false contouring effect on overlay images and allows the underlay to show through to give contours an anatomic context. The PET standardized uptake value (SUV) is used to control where colormap segments are masked. Examples show that SUV features can be extracted and blended with CT image instantaneously for viewing and diagnosis, and the non-feature part of the PET image is transparent. The proposed pixel-feature hybrid fusion highlights PET SUV features on CT images and reduces display clutters. It is easy to implement and can be used as complementarily to existing pixel-level fusion methods.

  11. Pixel classification based color image segmentation using quaternion exponent moments.

    PubMed

    Wang, Xiang-Yang; Wu, Zhi-Fang; Chen, Liang; Zheng, Hong-Liang; Yang, Hong-Ying

    2016-02-01

    Image segmentation remains an important, but hard-to-solve, problem since it appears to be application dependent with usually no a priori information available regarding the image structure. In recent years, many image segmentation algorithms have been developed, but they are often very complex and some undesired results occur frequently. In this paper, we propose a pixel classification based color image segmentation using quaternion exponent moments. Firstly, the pixel-level image feature is extracted based on quaternion exponent moments (QEMs), which can capture effectively the image pixel content by considering the correlation between different color channels. Then, the pixel-level image feature is used as input of twin support vector machines (TSVM) classifier, and the TSVM model is trained by selecting the training samples with Arimoto entropy thresholding. Finally, the color image is segmented with the trained TSVM model. The proposed scheme has the following advantages: (1) the effective QEMs is introduced to describe color image pixel content, which considers the correlation between different color channels, (2) the excellent TSVM classifier is utilized, which has lower computation time and higher classification accuracy. Experimental results show that our proposed method has very promising segmentation performance compared with the state-of-the-art segmentation approaches recently proposed in the literature.

  12. Multiport solid-state imager characterization at variable pixel rates

    SciTech Connect

    Yates, G.J.; Albright, K.A.; Turko, B.T.

    1993-08-01

    The imaging performance of an 8-port Full Frame Transfer Charge Coupled Device (FFT CCD) as a function of several parameters including pixel clock rate is presented. The device, model CCD- 13, manufactured by English Electric Valve (EEV) is a 512 {times} 512 pixel array designed with four individual programmable bidirectional serial registers and eight output amplifiers permitting simultaneous readout of eight segments (128 horizontal {times} 256 vertical pixels) of the array. The imager was evaluated in Los Alamos National Laboratory`s High-Speed Solid-State Imager Test Station at true pixel rates as high as 50 MHz for effective imager pixel rates approaching 400 MHz from multiporting. Key response characteristics measured include absolute responsivity, Charge-Transfer-Efficiency (CTE), dynamic range, resolution, signal-to-noise ratio, and electronic and optical crosstalk among the eight video channels. Preliminary test results and data obtained from the CCD-13 will be presented and the versatility/capabilities of the test station will be reviewed.

  13. Fabrication and performance of mercuric iodide pixellated detectors

    NASA Astrophysics Data System (ADS)

    van den Berg, Lodewijk; Bastian, Lloyd F.; Zhang, Feng; Lenos, Howard; Capote, M. Albert

    2007-09-01

    The radiation detection efficiency and spectral resolution of mercuric iodide detectors can be improved significantly by increasing the volume of the detectors and by using a pixellated anode structure. Detector bodies with a thickness of nominally 10 mm and an active area of approximately 14 mm x 14 mm have been used for these experiments. The detectors were cut from single crystals grown by the physical vapor transport method. The cut surfaces were polished and etched using a string saw and potassium iodide solutions. The Palladium contacts were deposited by magnetron sputtering through stainless steel masks. The cathode contact is continuous; the anode contacts consist of an array of 11 x 11 pixels surrounded by a guard ring. The resistance between a pixel and its surrounding contacts should be larger than 0.25 Gohm. The detector is mounted on a substrate that makes it possible to connect the anode pixels to an ASIC, and is conditioned so that it is stable for all pixels at a bias of -3000 Volts. Under these conditions the spectral resolution for Cs-137 gamma rays (662 keV) is approximately 5% FWHM. When depth sensing correction methods are applied, the resolution improves to about 2% FWHM or better. It is expected that the performance of the devices can be improved by the careful selection of crystal parts that are free of structural defects. Details of the fabrication technologies will be described. The effects of material inhomogeneities and transport properties of the charge carriers will be discussed.

  14. Robust electric-field tunable opto-electrical behavior in Pt-NiO-Pt planar structures

    PubMed Central

    Rebello, A.; Adeyeye, A. O.

    2016-01-01

    Capacitor-like metal-NiO-metal structures have attracted large interest in non-volatile memory applications based on electric field control of resistance, known as resistive switching (RS). Formation of conducting nanofilaments by the application of an electric field (electroformation) is considered an important pre-requisite for RS. Besides RS, due to the wide band gap and p-type semiconducting nature, NiO has been used to fabricate heterojunctions for photodetector applications. However, very little is known about the electrical and opto-electrical properties of NiO films in planar structure. Here, we demonstrate intriguing photoresponse and electrical behavior in electroformed Pt-NiO-Pt planar structures. While the pristine devices show ohmic electrical behavior and negligible photoresponse, the electroformed devices exhibit a nonlinear rectification behavior and a remarkable photoresponse at low voltage biases. More interestingly, the devices show a dramatic change of sign of rectification under light illumination at higher voltage biases. A polarity dependent and robust gain phenomenon is demonstrated in these devices. The large sensitivity, fast response, simple design and ease of preparation of these planar structures make them attractive for integration with current circuit technologies and various novel opto-electrical applications. PMID:27294614

  15. Opto-thermal study of cooling strategies for high-luminance white-light solid-state sources

    NASA Astrophysics Data System (ADS)

    Correia, António; Hanselaer, Peter; Meuret, Youri

    2016-06-01

    Solid-state sources have become ubiquitous is many lighting applications. For general lighting, phosphors are typically employed to produce white light from the narrowband light emitted from solid-state sources. As the optical output power from solid-state sources keeps increasing, increasingly higher luminance can be obtained, which, unfortunately, also increases the phosphor's temperature. These materials' colour conversion potential, encoded by the quantum yield, has complex dependencies with temperature. To obtain an accurate assessment of the performance of a high-luminance white light source configuration based on individual solid-state sources, it is imperative to accurately model the temperature distribution inside the phosphor material and consider the effect of temperature on the quantum yield of the phosphor. In addition, the feedback of the varying quantum yield on the generated heat inside the phosphor should also be considered. An opto-thermal framework has been previously proposed to accurately simulate the opto-thermal effects in phosphors when designing lighting systems. In this paper, this framework is applied to a novel optical configuration to investigate thermal bottlenecks and test cooling strategies to avoid them. For the specific configuration tested, using an active cooling strategy and concentrating the laser light on the phosphor region with the best thermal dissipation proved to be the best solutions.

  16. Probing opto-mechanical stresses within azobenzene-containing photosensitive polymer films by a thin metal film placed above.

    PubMed

    Yadavalli, Nataraja Sekhar; Korolkov, Denis; Moulin, Jean-François; Krutyeva, Margarita; Santer, Svetlana

    2014-07-23

    Azo-modified photosensitive polymers offer the interesting possibility to reshape bulk polymers and thin films by UV-irradiation while being in the solid glassy state. The polymer undergoes considerable mass transport under irradiation with a light interference pattern resulting in the formation of surface relief grating (SRG). The forces inscribing this SRG pattern into a thin film are hard to assess experimentally directly. In the current study, we are proposing a method to probe opto-mechanical stresses within polymer films by characterizing the mechanical response of thin metal films (10 nm) deposited on the photosensitive polymer. During irradiation, the metal film not only deforms along with the SRG formation but ruptures in a regular and complex manner. The morphology of the cracks differs strongly depending on the electrical field distribution in the interference pattern, even when the magnitude and the kinetics of the strain are kept constant. This implies a complex local distribution of the opto-mechanical stress along the topography grating. In addition, the neutron reflectivity measurements of the metal/polymer interface indicate the penetration of a metal layer within the polymer, resulting in a formation of a bonding layer that confirms the transduction of light-induced stresses in the polymer layer to a metal film.

  17. Community Links

    ERIC Educational Resources Information Center

    Nelson, Mary

    1975-01-01

    At Moraine Valley Community College (Illinois), a chain of events, programs, activities, and services has linked the college and community in such areas as fine arts, ethnic groups, public services, community action, community service, and community education. (Author/NHM)

  18. Link Analysis

    NASA Astrophysics Data System (ADS)

    Donoho, Steve

    Link analysis is a collection of techniques that operate on data that can be represented as nodes and links. This chapter surveys a variety of techniques including subgraph matching, finding cliques and K-plexes, maximizing spread of influence, visualization, finding hubs and authorities, and combining with traditional techniques (classification, clustering, etc). It also surveys applications including social network analysis, viral marketing, Internet search, fraud detection, and crime prevention.

  19. Simulation of digital pixel readout chip architectures with the RD53 SystemVerilog-UVM verification environment using Monte Carlo physics data

    NASA Astrophysics Data System (ADS)

    Conti, E.; Marconi, S.; Christiansen, J.; Placidi, P.; Hemperek, T.

    2016-01-01

    The simulation and verification framework developed by the RD53 collaboration is a powerful tool for global architecture optimization and design verification of next generation hybrid pixel readout chips. In this paper the framework is used for studying digital pixel chip architectures at behavioral level. This is carried out by simulating a dedicated, highly parameterized pixel chip description, which makes it possible to investigate different grouping strategies between pixels and different latency buffering and arbitration schemes. The pixel hit information used as simulation input can be either generated internally in the framework or imported from external Monte Carlo detector simulation data. The latter have been provided by both the CMS and ATLAS experiments, featuring HL-LHC operating conditions and the specifications related to the Phase 2 upgrade. Pixel regions and double columns were simulated using such Monte Carlo data as inputs: the performance of different latency buffering architectures was compared and the compliance of different link speeds with the expected column data rate was verified.

  20. Method and apparatus of high dynamic range image sensor with individual pixel reset

    NASA Technical Reports Server (NTRS)

    Yadid-Pecht, Orly (Inventor); Pain, Bedabrata (Inventor); Fossum, Eric R. (Inventor)

    2001-01-01

    A wide dynamic range image sensor provides individual pixel reset to vary the integration time of individual pixels. The integration time of each pixel is controlled by column and row reset control signals which activate a logical reset transistor only when both signals coincide for a given pixel.

  1. Planar pixel sensors for the ATLAS upgrade: beam tests results

    NASA Astrophysics Data System (ADS)

    Weingarten, J.; Altenheiner, S.; Beimforde, M.; Benoit, M.; Bomben, M.; Calderini, G.; Gallrapp, C.; George, M.; Gibson, S.; Grinstein, S.; Janoska, Z.; Jentzsch, J.; Jinnouchi, O.; Kishida, T.; La Rosa, A.; Libov, V.; Macchiolo, A.; Marchiori, G.; Muenstermann, D.; Nagai, R.; Piacquadio, G.; Ristic, B.; Rubinskiy, I.; Rummler, A.; Takubo, Y.; Troska, G.; Tsiskaridtze, S.; Tsurin, I.; Unno, Y.; Weigell, P.; Wittig, T.

    2012-10-01

    The performance of planar silicon pixel sensors, in development for the ATLAS Insertable B-Layer and High Luminosity LHC (HL-LHC) upgrades, has been examined in a series of beam tests at the CERN SPS facilities since 2009. Salient results are reported on the key parameters, including the spatial resolution, the charge collection and the charge sharing between adjacent cells, for different bulk materials and sensor geometries. Measurements are presented for n+-in-n pixel sensors irradiated with a range of fluences and for p-type silicon sensors with various layouts from different vendors. All tested sensors were connected via bump-bonding to the ATLAS Pixel read-out chip. The tests reveal that both n-type and p-type planar sensors are able to collect significant charge even after the lifetime fluence expected at the HL-LHC.

  2. The Phase-1 upgrade of the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Klein, Katja

    2017-02-01

    The CMS experiment features a pixel detector with three barrel layers and two discs per side, corresponding to an active silicon area of 1 m2. The detector delivered high-quality data during LHC Run 1. However, the CMS pixel detector was designed for the nominal instantaneous LHC luminosity of 1 ·1034cm-2s-1 . It is expected that the instantaneous luminosity will increase and reach twice the design value before Long Shutdown 3, scheduled for 2023. Under such conditions, the present readout chip would suffer from data loss due to buffer overflow, leading to significant inefficiencies of up to 16%. The CMS collaboration is presently constructing a new pixel detector to replace the present device during the winter shutdown 2016/2017. The design of this new detector will be outlined, the construction status summarized and the performance described.

  3. Visual mining geo-related data using pixel bar charts

    NASA Astrophysics Data System (ADS)

    Hao, Ming C.; Keim, Daniel A.; Dayal, Umeshwar; Wright, Peter; Schneidewind, Joern

    2005-03-01

    A common approach to analyze geo-related data is using bar charts or x-y plots. They are intuitive and easy to use. But important information often gets lost. In this paper, we introduce a new interactive visualization technique called Geo Pixel Bar Charts, which combines the advantages of Pixel Bar Charts and interactive maps. This technique allows analysts to visualize large amounts of spatial data without aggregation and shows the geographical regions corresponding to the spatial data attribute at the same time. In this paper, we apply Geo Pixel Bar Charts to visually mining sales transactions and Internet usage from different locations. Our experimental results show the effectiveness of this technique for providing data distribution and exceptions from the map.

  4. Virus based Full Colour Pixels using a Microheater

    PubMed Central

    Kim, Won-Geun; Kim, Kyujung; Ha, Sung-Hun; Song, Hyerin; Yu, Hyun-Woo; Kim, Chuntae; Kim, Jong-Man; Oh, Jin-Woo

    2015-01-01

    Mimicking natural structures has been received considerable attentions, and there have been a few practical advances. Tremendous efforts based on a self-assembly technique have been contributed to the development of the novel photonic structures which are mimicking nature’s inventions. We emulate the photonic structures from an origin of colour generation of mammalian skins and avian skin/feathers using M13 phage. The structures can be generated a full range of RGB colours that can be sensitively switched by temperature and substrate materials. Consequently, we developed an M13 phage-based temperature-dependent actively controllable colour pixels platform on a microheater chip. Given the simplicity of the fabrication process, the low voltage requirements and cycling stability, the virus colour pixels enable us to substitute for conventional colour pixels for the development of various implantable, wearable and flexible devices in future. PMID:26334322

  5. Wire Bond Encapsulation for the CMS Forward Pixel Upgrade

    NASA Astrophysics Data System (ADS)

    Higginbotham, Sam; CMS Collaboration

    2015-04-01

    The Phase 1 upgrade of the pixel tracker for the CMS experiment will require the assembly of approximately 1000 modules consisting of pixel sensors bump bonded to readout chips. Electrical connections between the custom readout chips and support ASIC's that constitute the front-end of the pixel data acquisition system are made via wire bonds to a thin printed circuit board. Part of the assembly process carried out at Purdue University includes the partial encapsulation of the wire bonds for mechanical protection, prevention of electrolytic corrosion, and to damp oscillations due to Lorentz forces from transient current pulses in large magnetic fields. We present the details of the robotic assembly process which allows the deposition of the viscous encapsulant compound with 100 micron precision.

  6. Acousto-optic imaging with a smart-pixels sensor

    NASA Astrophysics Data System (ADS)

    Barjean, K.; Contreras, K.; Laudereau, J.-B.; Tinet, E.; Ettori, D.; Ramaz, F.; Tualle, J.-M.

    2015-03-01

    Acousto-optic imaging (AOI) is an emerging technique in the field of biomedical optics which combines the optical contrast allowed by diffuse optical tomography with the resolution of ultrasound (US) imaging. In this work we report the implementation, for that purpose, of a CMOS smart-pixels sensor dedicated to the real-time analysis of speckle patterns. We implemented a highly sensitive lock-in detection in each pixel in order to extract the tagged photons after an appropriate in-pixel post-processing. With this system we can acquire images in scattering samples with a spatial resolution in the 2mm range, with an integration time compatible with the dynamic of living biological tissue.

  7. Calibration analysis software for the ATLAS Pixel Detector

    NASA Astrophysics Data System (ADS)

    Stramaglia, Maria Elena

    2016-07-01

    The calibration of the ATLAS Pixel Detector at LHC fulfils two main purposes: to tune the front-end configuration parameters for establishing the best operational settings and to measure the tuning performance through a subset of scans. An analysis framework has been set up in order to take actions on the detector given the outcome of a calibration scan (e.g. to create a mask for disabling noisy pixels). The software framework to control all aspects of the Pixel Detector scans and analyses is called calibration console. The introduction of a new layer, equipped with new FE-I4 chips, required an update of the console architecture. It now handles scans and scan analyses applied together to chips with different characteristics. An overview of the newly developed calibration analysis software will be presented, together with some preliminary results.

  8. Leakage current measurements of a pixelated polycrystalline CVD diamond detector

    NASA Astrophysics Data System (ADS)

    Zain, R. M.; Maneuski, D.; O'Shea, V.; Bates, R.; Blue, A.; Cunnigham, L.; Stehl, C.; Berderman, E.; Rahim, R. A.

    2013-01-01

    Diamond has several desirable features when used as a material for radiation detection. With the invention of synthetic growth techniques, it has become feasible to look at developing diamond radiation detectors with reasonable surface areas. Polycrystalline diamond has been grown using a chemical vapour deposition (CVD) technique by the University of Augsburg and detector structures fabricated at the James Watt Nanofabrication Centre (JWNC) in the University of Glasgow in order to produce pixelated detector arrays. The anode and cathode contacts are realised by depositing gold to produce ohmic contacts. Measurements of I-V characteristics were performed to study the material uniformity. The bias voltage is stepped from -1000V to 1000V to investigate the variation of leakage current from pixel to pixel. Bulk leakage current is measured to be less than 1nA.

  9. Testbeam and laboratory characterization of CMS 3D pixel sensors

    NASA Astrophysics Data System (ADS)

    Bubna, M.; Bortoletto, D.; Alagoz, E.; Krzywda, A.; Arndt, K.; Shipsey, I.; Bolla, G.; Hinton, N.; Kok, A.; Hansen, T.-E.; Summanwar, A.; Brom, J. M.; Boscardin, M.; Chramowicz, J.; Cumalat, J.; Dalla Betta, G. F.; Dinardo, M.; Godshalk, A.; Jones, M.; Krohn, M. D.; Kumar, A.; Lei, C. M.; Mendicino, R.; Moroni, L.; Perera, L.; Povoli, M.; Prosser, A.; Rivera, R.; Solano, A.; Obertino, M. M.; Kwan, S.; Uplegger, L.; Vigani, L.; Wagner, S.

    2014-07-01

    The pixel detector is the innermost tracking device in CMS, reconstructing interaction vertices and charged particle trajectories. The sensors located in the innermost layers of the pixel detector must be upgraded for the ten-fold increase in luminosity expected at the High-Luminosity LHC (HL-LHC). As a possible replacement for planar sensors, 3D silicon technology is under consideration due to its good performance after high radiation fluence. In this paper, we report on pre- and post- irradiation measurements of CMS 3D pixel sensors with different electrode configurations from different vendors. The effects of irradiation on electrical properties, charge collection efficiency, and position resolution are discussed. Measurements of various test structures for monitoring the fabrication process and studying the bulk and surface properties of silicon sensors, such as MOS capacitors, planar and gate-controlled diodes are also presented.

  10. Silicon pixel detector prototyping in SOI CMOS technology

    NASA Astrophysics Data System (ADS)

    Dasgupta, Roma; Bugiel, Szymon; Idzik, Marek; Kapusta, Piotr; Kucewicz, Wojciech; Turala, Michal

    2016-12-01

    The Silicon-On-Insulator (SOI) CMOS is one of the most advanced and promising technology for monolithic pixel detectors design. The insulator layer that is implemented inside the silicon crystal allows to integrate sensors matrix and readout electronic on a single wafer. Moreover, the separation of electronic and substrate increases also the SOI circuits performance. The parasitic capacitances to substrate are significantly reduced, so the electronic systems are faster and consume much less power. The authors of this presentation are the members of international SOIPIX collaboration, that is developing SOI pixel detectors in 200 nm Lapis Fully-Depleted, Low-Leakage SOI CMOS. This work shows a set of advantages of SOI technology and presents possibilities for pixel detector design SOI CMOS. In particular, the preliminary results of a Cracow chip are presented.

  11. Simulation of Caliste-SO single pixel response

    NASA Astrophysics Data System (ADS)

    Barylak, J.; Barylak, A.; Mrozek, T.; Podgórski, P.; Steślicki, M.; Ścisłowski, D.

    2016-09-01

    The paper presents a method for determining the pixel response using Geant4 package. The response is calculated for cadmium telluride sensor of Caliste-SO detector. Caliste-SO will be used in STIX instrument on board Solar Orbiter, which is M-class mission of the ESA's program Cosmic Vision 2015-2025. Solar Orbiter is to be launched in October 2018. STIX instrument will provide imaging spectroscopy of solar hard X-ray emissions (4 - 150 keV) using a Fourier-imaging technique. Response of pixels in pixelized Caliste-SO detector vary between each other due to different sizes and locations. This can influence the scientific data obtained from STIX. Additionally, in the simulation we considered detector effects, like: hole tailing, damage layer, Fano and electronic noise.

  12. Performance of the INTPIX6 SOI pixel detector

    NASA Astrophysics Data System (ADS)

    Arai, Y.; Bugiel, Sz.; Dasgupta, R.; Idzik, M.; Kapusta, P.; Kucewicz, W.; Miyoshi, T.; Turala, M.

    2017-01-01

    Characterization of the monolithic pixel detector INPTIX6, designed at KEK and fabricated in Lapis 0.2 μ m Fully-Depleted, Low-Leakage Silicon-On-Insulator (SOI) CMOS technology, was performed. The INTPIX6 comprises a large area of 1408 × 896 integrating type squared pixels of 12 micron pitch. In this work the performance and measurement results of the prototypes produced on lower resistivity Czochralski type (CZ-n) and high resistivity floating zone (FZ-n) sensor wafers are presented. Using 241Am radioactive source the noise of INTPIX6 was measured, showing the ENC (Equivalent Noise Charge) of about 70 e-. The resolution calculated from the FWHM of the Iron-55 X-ray peak was about 100 e-. The radiation hardness of the SOI pixel detector was also investigated. The CZ-n type INTPIX6 received a dose of 60 krad and its performance has been continuously monitored during the irradiation.

  13. Virus based Full Colour Pixels using a Microheater

    NASA Astrophysics Data System (ADS)

    Kim, Won-Geun; Kim, Kyujung; Ha, Sung-Hun; Song, Hyerin; Yu, Hyun-Woo; Kim, Chuntae; Kim, Jong-Man; Oh, Jin-Woo

    2015-09-01

    Mimicking natural structures has been received considerable attentions, and there have been a few practical advances. Tremendous efforts based on a self-assembly technique have been contributed to the development of the novel photonic structures which are mimicking nature’s inventions. We emulate the photonic structures from an origin of colour generation of mammalian skins and avian skin/feathers using M13 phage. The structures can be generated a full range of RGB colours that can be sensitively switched by temperature and substrate materials. Consequently, we developed an M13 phage-based temperature-dependent actively controllable colour pixels platform on a microheater chip. Given the simplicity of the fabrication process, the low voltage requirements and cycling stability, the virus colour pixels enable us to substitute for conventional colour pixels for the development of various implantable, wearable and flexible devices in future.

  14. HEXITEC ASIC—a pixellated readout chip for CZT detectors

    NASA Astrophysics Data System (ADS)

    Jones, Lawrence; Seller, Paul; Wilson, Matthew; Hardie, Alec

    2009-06-01

    HEXITEC is a collaborative project with the aim of developing a new range of detectors for high-energy X-ray imaging. High-energy X-ray imaging has major advantages over current lower energy imaging for the life and physical sciences, including improved phase-contrast images on larger, higher density samples and with lower accumulated doses. However, at these energies conventional silicon-based devices cannot be used, hence, the requirement for a new range of high Z-detector materials. Underpinning the HEXITEC programme are the development of a pixellated Cadmium Zinc Telluride (CZT) detectors and a pixellated readout ASIC which will be bump-bonded to the detector. The HEXITEC ASIC is required to have low noise (20 electrons rms) and tolerate detector leakage currents. A prototype 20×20 pixel ASIC has been developed and manufactured on a standard 0.35 μm CMOS process.

  15. Classification of multispectral image data by the Binary Diamond neural network and by nonparametric, pixel-by-pixel methods

    NASA Technical Reports Server (NTRS)

    Salu, Yehuda; Tilton, James

    1993-01-01

    The classification of multispectral image data obtained from satellites has become an important tool for generating ground cover maps. This study deals with the application of nonparametric pixel-by-pixel classification methods in the classification of pixels, based on their multispectral data. A new neural network, the Binary Diamond, is introduced, and its performance is compared with a nearest neighbor algorithm and a back-propagation network. The Binary Diamond is a multilayer, feed-forward neural network, which learns from examples in unsupervised, 'one-shot' mode. It recruits its neurons according to the actual training set, as it learns. The comparisons of the algorithms were done by using a realistic data base, consisting of approximately 90,000 Landsat 4 Thematic Mapper pixels. The Binary Diamond and the nearest neighbor performances were close, with some advantages to the Binary Diamond. The performance of the back-propagation network lagged behind. An efficient nearest neighbor algorithm, the binned nearest neighbor, is described. Ways for improving the performances, such as merging categories, and analyzing nonboundary pixels, are addressed and evaluated.

  16. Imaging by photon counting with 256x256 pixel matrix

    NASA Astrophysics Data System (ADS)

    Tlustos, Lukas; Campbell, Michael; Heijne, Erik H. M.; Llopart, Xavier

    2004-09-01

    Using 0.25µm standard CMOS we have developed 2-D semiconductor matrix detectors with sophisticated functionality integrated inside each pixel of a hybrid sensor module. One of these sensor modules is a matrix of 256x256 square 55µm pixels intended for X-ray imaging. This device is called 'Medipix2' and features a fast amplifier and two-level discrimination for signals between 1000 and 100000 equivalent electrons, with overall signal noise ~150 e- rms. Signal polarity and comparator thresholds are programmable. A maximum count rate of nearly 1 MHz per pixel can be achieved, which corresponds to an average flux of 3x10exp10 photons per cm2. The selected signals can be accumulated in each pixel in a 13-bit register. The serial readout takes 5-10 ms. A parallel readout of ~300 µs could also be used. Housekeeping functions such as local dark current compensation, test pulse generation, silencing of noisy pixels and threshold tuning in each pixel contribute to the homogeneous response over a large sensor area. The sensor material can be adapted to the energy of the X-rays. Best results have been obtained with high-resistivity silicon detectors, but also CdTe and GaAs detectors have been used. The lowest detectable X-ray energy was about 4 keV. Background measurements have been made, as well as measurements of the uniformity of imaging by photon counting. Very low photon count rates are feasible and noise-free at room temperature. The readout matrix can be used also with visible photons if an energy or charge intensifier structure is interposed such as a gaseous amplification layer or a microchannel plate or acceleration field in vacuum.

  17. SLHC upgrade plans for the ATLAS pixel detector

    NASA Astrophysics Data System (ADS)

    Šícho, Petr

    2009-08-01

    The ATLAS pixel detector is an 80 million channels silicon tracking system designed to detect charged tracks and secondary vertices with very high precision. An upgrade of the ATLAS pixel detector is presently being considered, enabling to cope with higher luminosity at Super Large Hadron Collider (SLHC). The increased luminosity leads to extremely high radiation doses in the innermost region of the ATLAS tracker. Options considered for a new detector are discussed, as well as some important R&D activities, such as investigations towards novel detector geometries and novel processes.

  18. Highly Reflective Multi-stable Electrofluidic Display Pixels

    NASA Astrophysics Data System (ADS)

    Yang, Shu

    Electronic papers (E-papers) refer to the displays that mimic the appearance of printed papers, but still owning the features of conventional electronic displays, such as the abilities of browsing websites and playing videos. The motivation of creating paper-like displays is inspired by the truths that reading on a paper caused least eye fatigue due to the paper's reflective and light diffusive nature, and, unlike the existing commercial displays, there is no cost of any form of energy for sustaining the displayed image. To achieve the equivalent visual effect of a paper print, an ideal E-paper has to be a highly reflective with good contrast ratio and full-color capability. To sustain the image with zero power consumption, the display pixels need to be bistable, which means the "on" and "off" states are both lowest energy states. Pixel can change its state only when sufficient external energy is given. There are many emerging technologies competing to demonstrate the first ideal E-paper device. However, none is able to achieve satisfactory visual effect, bistability and video speed at the same time. Challenges come from either the inherent physical/chemical properties or the fabrication process. Electrofluidic display is one of the most promising E-paper technologies. It has successfully demonstrated high reflectivity, brilliant color and video speed operation by moving colored pigment dispersion between visible and invisible places with electrowetting force. However, the pixel design did not allow the image bistability. Presented in this dissertation are the multi-stable electrofluidic display pixels that are able to sustain grayscale levels without any power consumption, while keeping the favorable features of the previous generation electrofluidic display. The pixel design, fabrication method using multiple layer dry film photoresist lamination, and physical/optical characterizations are discussed in details. Based on the pixel structure, the preliminary

  19. Mapping Pixel Windows To Vectors For Parallel Processing

    NASA Technical Reports Server (NTRS)

    Duong, Tuan A.

    1996-01-01

    Mapping performed by matrices of transistor switches. Arrays of transistor switches devised for use in forming simultaneous connections from square subarray (window) of n x n pixels within electronic imaging device containing np x np array of pixels to linear array of n(sup2) input terminals of electronic neural network or other parallel-processing circuit. Method helps to realize potential for rapidity in parallel processing for such applications as enhancement of images and recognition of patterns. In providing simultaneous connections, overcomes timing bottleneck or older multiplexing, serial-switching, and sample-and-hold methods.

  20. CMOS VLSI Active-Pixel Sensor for Tracking

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata; Sun, Chao; Yang, Guang; Heynssens, Julie

    2004-01-01

    An architecture for a proposed active-pixel sensor (APS) and a design to implement the architecture in a complementary metal oxide semiconductor (CMOS) very-large-scale integrated (VLSI) circuit provide for some advanced features that are expected to be especially desirable for tracking pointlike features of stars. The architecture would also make this APS suitable for robotic- vision and general pointing and tracking applications. CMOS imagers in general are well suited for pointing and tracking because they can be configured for random access to selected pixels and to provide readout from windows of interest within their fields of view. However, until now, the architectures of CMOS imagers have not supported multiwindow operation or low-noise data collection. Moreover, smearing and motion artifacts in collected images have made prior CMOS imagers unsuitable for tracking applications. The proposed CMOS imager (see figure) would include an array of 1,024 by 1,024 pixels containing high-performance photodiode-based APS circuitry. The pixel pitch would be 9 m. The operations of the pixel circuits would be sequenced and otherwise controlled by an on-chip timing and control block, which would enable the collection of image data, during a single frame period, from either the full frame (that is, all 1,024 1,024 pixels) or from within as many as 8 different arbitrarily placed windows as large as 8 by 8 pixels each. A typical prior CMOS APS operates in a row-at-a-time ( grolling-shutter h) readout mode, which gives rise to exposure skew. In contrast, the proposed APS would operate in a sample-first/readlater mode, suppressing rolling-shutter effects. In this mode, the analog readout signals from the pixels corresponding to the windows of the interest (which windows, in the star-tracking application, would presumably contain guide stars) would be sampled rapidly by routing them through a programmable diagonal switch array to an on-chip parallel analog memory array. The

  1. The BTeV pixel and microstrip detector

    SciTech Connect

    Simon W Kwan

    2003-06-04

    The BTeV pixel detector is one of the most crucial elements in the BTeV experiment. While the pixel detector is technically challenging, we have made great progress towards identifying viable solutions for individual components of the system. The forward silicon tracker is based on more mature technology and its design has benefited from the experience of other experiments. Nevertheless, we have started an R&D program on the forward silicon tracker and first results are expected some time next year.

  2. 320 Gbps to 10 GHz sub-clock recovery using a PPLN-based opto-electronic phase-locked loop.

    PubMed

    Ware, Cédric; Oxenløwe, Leif K; Gómez Agis, Fausto; Mulvad, Hans C; Galili, Michael; Kurimura, Sunao; Nakajima, Hirochika; Ichikawa, Junichiro; Erasme, Didier; Clausen, Anders T; Jeppesen, Palle

    2008-03-31

    We present successful extraction of a 10 GHz clock from single-wavelength 160 and 320 Gbps OTDM data streams, using an opto-electronic phase-locked loop based on three-wave mixing in periodically-poled lithium niobate as a phase comparator.

  3. Superconductive Microwave Single-Flux-Quantum Digital Circuits and Corresponding Opto-Electronic Interfaces: On-Going Studies and First Experimental Results

    DTIC Science & Technology

    2005-07-13

    UHLMANN University of Technology Ilmenau– PO Box 105565 – D-98684 Ilmenau - Germany RESUME : Les circuits numériques supraconducteurs micro-ondes...circuits RSFQ. Ce banc de mesure comporte deux types d’interfaces opto-RSFQ, basées sur des matériaux semiconducteurs et supraconducteurs , respectivement

  4. Fully depleted CMOS pixel sensor development and potential applications

    SciTech Connect

    Baudot, J.; Kachel, M.

    2015-07-01

    CMOS pixel sensors are often opposed to hybrid pixel sensors due to their very different sensitive layer. In standard CMOS imaging processes, a thin (about 20 μm) low resistivity epitaxial layer acts as the sensitive volume and charge collection is mostly driven by thermal agitation. In contrast, the so-called hybrid pixel technology exploits a thick (typically 300 μm) silicon sensor with high resistivity allowing for the depletion of this volume, hence charges drift toward collecting electrodes. But this difference is fading away with the recent availability of some CMOS imaging processes based on a relatively thick (about 50 μm) high resistivity epitaxial layer which allows for full depletion. This evolution extents the range of applications for CMOS pixel sensors where their known assets, high sensitivity and granularity combined with embedded signal treatment, could potentially foster breakthrough in detection performances for specific scientific instruments. One such domain is the Xray detection for soft energies, typically below 10 keV, where the thin sensitive layer was previously severely impeding CMOS sensor usage. Another application becoming realistic for CMOS sensors, is the detection in environment with a high fluence of non-ionizing radiation, such as hadron colliders. However, when considering highly demanding applications, it is still to be proven that micro-circuits required to uniformly deplete the sensor at the pixel level, do not mitigate the sensitivity and efficiency required. Prototype sensors in two different technologies with resistivity higher than 1 kΩ, sensitive layer between 40 and 50 μm and featuring pixel pitch in the range 25 to 50 μm, have been designed and fabricated. Various biasing architectures were adopted to reach full depletion with only a few volts. Laboratory investigations with three types of sources (X-rays, β-rays and infrared light) demonstrated the validity of the approach with respect to depletion, keeping a

  5. Monitoring Spacecraft Telemetry Via Optical or RF Link

    NASA Technical Reports Server (NTRS)

    Fielhauer, K. B.; Boone, B. G.

    2011-01-01

    A patent disclosure document discusses a photonic method for connecting a spacecraft with a launch vehicle upper-stage telemetry system as a means for monitoring a spacecraft fs health and status during and right after separation and deployment. This method also provides an efficient opto-coupled capability for prelaunch built-in-test (BIT) on the ground to enable more efficient and timely integration, preflight checkout, and a means to obviate any local EMI (electromagnetic interference) during integration and test. Additional utility can be envisioned for BIT on other platforms, such as the International Space Station (ISS). The photonic telemetry system implements an optical free-space link with a divergent laser transmitter beam spoiled over a significant cone angle to accommodate changes in spacecraft position without having to angle track it during deployment. Since the spacecraft may lose attitude control and tumble during deployment, the transmitted laser beam interrogates any one of several low-profile meso-scale retro-reflective spatial light modulators (SLMs) deployed over the surface of the spacecraft. The return signal beam, modulated by the SLMs, contains health, status, and attitude information received back at the launch vehicle. Very compact low-power opto-coupler technology already exists for the received signal (requiring relatively low bandwidths, e.g., .200 kbps) to enable transfer to a forward pass RF relay from the launch vehicle to TDRSS (Tracking and Data Relay Satellite System) or another recipient. The link would be active during separation and post-separation to monitor spacecraft health, status, attitude, or other data inventories until attitude recovery and ground control can be re-established. An optical link would not interfere with the existing upper stage telemetry and beacon systems, thus meeting launch vehicle EMI environmental constraints.

  6. How spectroscopic x-ray imaging benefits from inter-pixel communication

    NASA Astrophysics Data System (ADS)

    Koenig, Thomas; Zuber, Marcus; Hamann, Elias; Cecilia, Angelica; Ballabriga, Rafael; Campbell, Michael; Ruat, Marie; Tlustos, Lukas; Fauler, Alex; Fiederle, Michael; Baumbach, Tilo

    2014-10-01

    Spectroscopic x-ray imaging based on pixellated semiconductor detectors can be sensitive to charge sharing and K-fluorescence, depending on the sensor material used, its thickness and the pixel pitch employed. As a consequence, spectroscopic resolution is partially lost. In this paper, we study a new detector ASIC, the Medipix3RX, that offers a novel feature called charge summing, which is established by making adjacent pixels communicate with each other. Consequently, single photon interactions resulting in multiple hits are almost completely avoided. We investigate this charge summing mode with respect to those of its imaging properties that are of interest in medical physics and benchmark them against the case without charge summing. In particular, we review its influence on spectroscopic resolution and find that the low energy bias normally present when recording energy spectra is dramatically reduced. Furthermore, we show that charge summing provides a modulation transfer function which is almost independent of the energy threshold setting, which is in contrast to approaches common so far. We demonstrate that this property is directly linked to the detective quantum efficiency, which is found to increase by a factor of three or more when the energy threshold approaches the photon energy and when using charge summing. As a consequence, the contrast-to-noise ratio is found to double at elevated threshold levels and the dynamic range increases for a given counter depth. All these effects are shown to lead to an improved ability to perform material discrimination in spectroscopic CT, using iodine and gadolinium contrast agents. Hence, when compared to conventional photon counting detectors, these benefits carry the potential of substantially reducing the imaging dose a patient is exposed to during diagnostic CT examinations.

  7. Phase 1 upgrade of the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Saha, Anirban

    2017-02-01

    The pixel tracker of the Compact Muon Solenoid (CMS) experiment is the innermost sub-detector, located close to the collision point, and is used for reconstruction of the tracks and vertices of charged particles. The present pixel detector was designed to work efficiently with the maximum instantaneous luminosity of 1 × 1034 cm‑2 s‑1. In 2017 the Large Hadron Collider (LHC) is expected to deliver a peak luminosity reaching up to 2 × 1034 cm‑2 s‑1, increasing the mean number of primary vertices to 50. Due to the radiation damage and significant data losses due to high occupancy in the readout chip of the pixel detector, the present system must be replaced by a new one in an extended end-of-year shutdown during winter 2016/2017 in order to maintain the excellent tracking and other physics performances. The main new features of the upgraded pixel detector are a ultra-light mechanical design with four barrel layers and three end-cap disks, digital readout chip with higher rate capability and a new cooling system. In this document, we discuss the motivations for the upgrade, the design, and technological choices made, the status of the construction of the new detector and the future plans for the installation and commissioning.

  8. Optimization of Focusing by Strip and Pixel Arrays

    SciTech Connect

    Burke, G J; White, D A; Thompson, C A

    2005-06-30

    Professor Kevin Webb and students at Purdue University have demonstrated the design of conducting strip and pixel arrays for focusing electromagnetic waves [1, 2]. Their key point was to design structures to focus waves in the near field using full wave modeling and optimization methods for design. Their designs included arrays of conducting strips optimized with a downhill search algorithm and arrays of conducting and dielectric pixels optimized with the iterative direct binary search method. They used a finite element code for modeling. This report documents our attempts to duplicate and verify their results. We have modeled 2D conducting strips and both conducting and dielectric pixel arrays with moment method and FDTD codes to compare with Webb's results. New designs for strip arrays were developed with optimization by the downhill simplex method with simulated annealing. Strip arrays were optimized to focus an incident plane wave at a point or at two separated points and to switch between focusing points with a change in frequency. We also tried putting a line current source at the focus point for the plane wave to see how it would work as a directive antenna. We have not tried optimizing the conducting or dielectric pixel arrays, but modeled the structures designed by Webb with the moment method and FDTD to compare with the Purdue results.

  9. Sub-pixel localization of highways in AVIRIS images

    NASA Technical Reports Server (NTRS)

    Salu, Yehuda

    1995-01-01

    Roads and highways show up clearly in many bands of AVIRIS images. A typical lane in the U.S. is 12 feet wide, and the total width of a four lane highway, including 18 feet of paved shoulders, is 19.8 m. Such a highway will cover only a portion of any 20x20 m AVIRIS pixel that it traverses. The other portion of these pixels wil be usually covered by vegetation. An interesting problem is to precisely determine the location of a highway within the AVIRIS pixels that it traverses. This information may be used for alignment and spatial calibration of AVIRIS images. Also, since the reflection properties of highway surfaces do not change with time, and they can be determined once and for all, such information can be of help in calculating and filtering out the atmospheric noise that contaminates AVIRIS measurements. The purpose of this report is to describe a method for sub-pixel localization of highways.

  10. Metamaterial-based single pixel imaging system (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Padilla, Willie; Watts, Claire M.; Nadell, Christian; Montoya, John A.; Krishna, Sanjay

    2015-09-01

    Single pixel cameras are useful imaging devices where it is difficult or infeasible to fashion focal plan arrays. For example in the Far Infrared (FIR) it is difficult to perform imaging by conventional detector arrays, owing to the cost and size of such an array. The typical single pixel camera uses a spatial light modulator (SLM) - placed in the conjugate image plane - and is used to sample various portions of the image. The spatially modulated light emerging from the SLM is then sent to a single detector where the light is condensed with suitable optics for detection. Conventional SLMs are either based on liquid crystals or digital mirror devices. As such these devices are limited in modulation speeds of order 30 kHz. Further there is little control over the type of light that is modulated. We present metamaterial based spatial light modulators which provide the ability to digitally encode images - with various measurement matrix coefficients - thus permitting high speed and fidelity imaging capability. In particular we use the Hadamard matrix and related S-matrix to encode images for single pixel imaging. Metamaterials thus permit imaging in regimes of the electromagnetic spectrum where conventional SLMs are not available. Additionally, metamaterials offer several salient features that are not available with commercial SLMs. For example, metamaterials may be used to enable hyperspectral, polarimetric, and phase sensitive imaging. We present the theory and experimental results of single pixel imaging with digital metamaterials in the far infrared and highlight the future of this exciting field.

  11. Advancement in 17-micron pixel pitch uncooled focal plane arrays

    NASA Astrophysics Data System (ADS)

    Li, Chuan; Skidmore, George; Howard, Christopher; Clarke, Elwood; Han, C. J.

    2009-05-01

    This paper provides an update of 17 micron pixel pitch uncooled microbolometer development at DRS. Since the introduction of 17 micron pitch 640x480 focal plane arrays (FPAs) in 2006, significant progress has been made in sensor performance and manufacturing processes. The FPAs are now in initial production with an FPA noise equivalent temperature difference (NETD), detector thermal time constant, and pixel operability equivalent or better than that of the current 25 micron pixel pitch production FPAs. NETD improvement was achieved without compromising detector thermal response or thermal time constant by simultaneous reduction in bolometer heat capacity and thermal conductance. In addition, the DRS unique "umbrella" microbolometer cavities were optically tuned to optimize detector radiation absorption for specific spectral band applications. The 17 micron pixel pitch FPAs are currently being considered for the next generation soldier systems such as thermal weapon sights (TWS), vehicle driver vision enhancers (DVE), digitally fused enhanced night vision goggles (DENVG) and unmanned air vehicle (UAV) surveillance sensors, because of overall thermal imaging system size, weight and power advantages.

  12. The pixel tracking telescope at the Fermilab Test Beam Facility

    DOE PAGES

    Kwan, Simon; Lei, CM; Menasce, Dario; ...

    2016-03-01

    An all silicon pixel telescope has been assembled and used at the Fermilab Test Beam Facility (FTBF) since 2009 to provide precise tracking information for different test beam experiments with a wide range of Detectors Under Test (DUTs) requiring high resolution measurement of the track impact point. The telescope is based on CMS pixel modules left over from the CMS forward pixel production. Eight planes are arranged to achieve a resolution of less than 8 μm on the 120 GeV proton beam transverse coordinate at the DUT position. In order to achieve such resolution with 100 × 150 μm2 pixelmore » cells, the planes were tilted to 25 degrees to maximize charge sharing between pixels. Crucial for obtaining this performance is the alignment software, called Monicelli, specifically designed and optimized for this system. This paper will describe the telescope hardware, the data acquisition system and the alignment software constituting this particle tracking system for test beam users.« less

  13. High responsivity CMOS imager pixel implemented in SOI technology

    NASA Technical Reports Server (NTRS)

    Zheng, X.; Wrigley, C.; Yang, G.; Pain, B.

    2000-01-01

    Availability of mature sub-micron CMOS technology and the advent of the new low noise active pixel sensor (APS) concept have enabled the development of low power, miniature, single-chip, CMOS digital imagers in the decade of the 1990's.

  14. Gauss-Legendre Sky Pixelization (glesp) for CMB Maps

    NASA Astrophysics Data System (ADS)

    Doroshkevich, A. G.; Naselsky, P. D.; Verkhodanov, O. V.; Novikov, D. I.; Turchaninov, V. I.; Novikov, I. D.; Christensen, P. R.; Chiang, L.-Y.

    A new scheme of sky pixelization is developed for CMB maps. The scheme is based on the Gauss-Legendre polynomials zeros and allows one to create strict orthogonal expansion of the map. A corresponding code has been implemented and comparison with other methods has been done.

  15. Pixel Analysis and Plasma Dynamics Characterized by Photospheric Spectral Data

    NASA Astrophysics Data System (ADS)

    Rasca, Anthony P.; Chen, James; Pevtsov, Alexei A.

    2016-05-01

    Recent observations of the photosphere using high spatial and temporal resolutions show small dynamic features at the resolving limit during emerging flux events. However, line-of-sight (LOS) magnetogram pixels only contain the net uncanceled magnetic flux, which is expected to increase for fixed regions as resolution limits improve. A new pixel dynamics method uses spectrographic images to characterize photospheric absorption line profiles by variations in line displacement, width, asymmetry, and peakedness and is applied to quiet-sun regions, active regions with no eruption, and an active region with an ongoing eruption. Using Stokes I images from SOLIS/VSM on 2012 March 13, variations in line width and peakedness of Fe I 6301.5 Å are shown to have a strong spatial and temporal relationship with an M7.9 X-ray flare originating from NOAA 11429. This relationship is observed as a flattening in the line profile as the X-ray flare approaches peak intensity and was not present in area scans of a non-eruptive active region on 2011 April 14. These results are used to estimate dynamic plasma properties on sub-pixel scales and provide both spatial and temporal information of sub-pixel activity at the photosphere. The analysis can be extended to include the full Stokes parameters and study signatures of magnetic fields and coupled plasma properties.

  16. Diamond pixel modules and the ATLAS beam conditions monitor

    NASA Astrophysics Data System (ADS)

    Dobos, D.; Pernegger, Heinz; RD42 Collaboration; ATLAS Diamond Pixel Upgrade Collaboration; ATLAS Beam Conditions Monitor Collaborations

    2011-02-01

    Chemical vapor deposition diamonds are considered among possible sensor materials for the next pixel upgrade in ATLAS. Full size diamond pixel modules have been constructed to the specification of the ATLAS Pixel Detector using poly-crystalline CVD diamond sensors to develop the production techniques required for industrial production. Those modules were tested in the lab and testbeam. Additionally we will present results of diamond pixel modules using single-crystal diamonds and results of proton irradiations up to 1.8 ×10 16 protons/cm 2. The ATLAS Beam Conditions Monitors (BCM) main purpose is to protect the experiments silicon tracker from beam incidents. In total 16 1×1 cm2 500 μm thick diamond pCVD sensors are used in eight positions around the LHC interaction point. They perform time difference measurements with sub nanosecond resolution to distinguish between particles from a collision and spray particles from a beam incident; an abundance of the latter can lead the BCM to provoke an abort of LHC beam. The BCM diamond detector modules, their readout system and the algorithms used to detect beam incidents are described. Results of the BCM operation with circulating LHC beams and its commissioning with first LHC collisions are reported.

  17. Photovoltaic Pixels for Neural Stimulation: Circuit Models and Performance.

    PubMed

    Boinagrov, David; Lei, Xin; Goetz, Georges; Kamins, Theodore I; Mathieson, Keith; Galambos, Ludwig; Harris, James S; Palanker, Daniel

    2016-02-01

    Photovoltaic conversion of pulsed light into pulsed electric current enables optically-activated neural stimulation with miniature wireless implants. In photovoltaic retinal prostheses, patterns of near-infrared light projected from video goggles onto subretinal arrays of photovoltaic pixels are converted into patterns of current to stimulate the inner retinal neurons. We describe a model of these devices and evaluate the performance of photovoltaic circuits, including the electrode-electrolyte interface. Characteristics of the electrodes measured in saline with various voltages, pulse durations, and polarities were modeled as voltage-dependent capacitances and Faradaic resistances. The resulting mathematical model of the circuit yielded dynamics of the electric current generated by the photovoltaic pixels illuminated by pulsed light. Voltages measured in saline with a pipette electrode above the pixel closely matched results of the model. Using the circuit model, our pixel design was optimized for maximum charge injection under various lighting conditions and for different stimulation thresholds. To speed discharge of the electrodes between the pulses of light, a shunt resistor was introduced and optimized for high frequency stimulation.

  18. Detection and compensation of bad pixel for CMOS image sensor

    NASA Astrophysics Data System (ADS)

    Xu, Youqing; Yu, Shengsheng; Zhou, Jingli; Fang, Zuyuan

    2000-05-01

    This paper presents a detailed analysis of the occurring reason and features of bad pixels in CMOS image sensor. Detect and compensate algorithms have also bee introduced. Experimental result show that the algorithms are efficiently when they are applied on CH5001 produced by Chrontel Inc.

  19. Use of silicon pixel detectors in double electron capture experiments

    NASA Astrophysics Data System (ADS)

    Cermak, P.; Stekl, I.; Shitov, Yu A.; Mamedov, F.; Rukhadze, E. N.; Jose, J. M.; Cermak, J.; Rukhadze, N. I.; Brudanin, V. B.; Loaiza, P.

    2011-01-01

    A novel experimental approach to search for double electron capture (EC/EC) is discussed in this article. R&D for a new generation EC/EC spectrometer based on silicon pixel detectors (SPDs) has been conducted since 2009 for an upgrade of the TGV experiment. SPDs built on Timepix technology with a spectroscopic readout from each individual pixel are an effective tool to detect the 2νEC/EC signature of the two low energy X-rays hitting two separate pixels. The ability of SPDs to indentify α/β/γ particles and localize them precisely leads to effective background discrimination and thus considerable improvement of the signal-to-background ratio (S/B). A multi-SPD system, called a Silicon Pixel Telescope (SPT), is planned based on the experimental approach of the TGV calorimeter which measures thin foils of enriched EC/EC-isotope sandwiched between HPGe detectors working in coincidence mode. The sources of SPD internal background have been identified by measuring SPD radiopurity with a low-background HPGe detector as well as by long-term SPD background runs in the Modane underground laboratory (LSM, France), and results of these studies are presented.

  20. Fourier transform demodulation of pixelated phase-masked interferograms.

    PubMed

    Servin, M; Estrada, J C; Medina, O

    2010-07-19

    Recently a new type of spatial phase shifting interferometer was proposed that uses a phase-mask over the camera's pixels. This new interferometer allows one to phase modulate each pixel independently by setting the angle of a linear polarizer built in contact over the camera's CCD. In this way neighbor pixels may have any desired (however fixed) phase shift without cross taking. The standard manufacturing of these interferometers uses a 2x2 array with phase-shifts of 0, pi/2, pi, and 3 pi/2 radians. This 2x2 array is tiled all over the video camera's CCD. In this paper we propose a new way to phase demodulate these phase-masked interferograms using the squeezing phase-shifting technique. A notable advantage of this squeezing technique is that it allows one the use of Fourier interferometry wiping out the detuning error that most phase shifting algorithms suffers. Finally we suggest the use of an alternative phase-mask to phase modulate the camera's pixels using a linear spatial carrier along a given axis.

  1. Harmonics rejection in pixelated interferograms using spatio-temporal demodulation.

    PubMed

    Padilla, J M; Servin, M; Estrada, J C

    2011-09-26

    Pixelated phase-mask interferograms have become an industry standard in spatial phase-shifting interferometry. These pixelated interferograms allow full wavefront encoding using a single interferogram. This allows the study of fast dynamic events in hostile mechanical environments. Recently an error-free demodulation method for ideal pixelated interferograms was proposed. However, non-ideal conditions in interferometry may arise due to non-linear response of the CCD camera, multiple light paths in the interferometer, etc. These conditions generate non-sinusoidal fringes containing harmonics which degrade the phase estimation. Here we show that two-dimensional Fourier demodulation of pixelated interferograms rejects most harmonics except the complex ones at {-3(rd), +5(th), -7(th), +9(th), -11(th),…}. We propose temporal phase-shifting to remove these remaining harmonics. In particular, a 2-step phase-shifting algorithm is used to eliminate the -3(rd) and +5(th) complex harmonics, while a 3-step one is used to remove the -3(rd), +5<(th), -7(th) and +9(th) complex harmonics.

  2. Overview of the BTeV Pixel Detector

    SciTech Connect

    Jeffrey A Appel

    2002-12-10

    BTeV is a new Fermilab beauty and charm experiment designed to operate in the CZero region of the Tevatron collider. Critical to the success of BTeV is its pixel detector. The unique features of this pixel detector include its proximity to the beam, its operation with a beam crossing time of 132 ns, and the need for the detector information to be read out quickly enough to be used for the lowest level trigger. This talk presents an overview of the pixel detector design, giving the motivations for the technical choices made. The status of the current R&D on detector components is also reviewed. Additional Pixel 2002 talks on the BTeV pixel detector are given by Dave Christian[1], Mayling Wong[2], and Sergio Zimmermann[3]. Table 1 gives a selection of pixel detector parameters for the ALICE, ATLAS, BTeV, and CMS experiments. Comparing the progression of this table, which I have been updating for the last several years, has shown a convergence of specifications. Nevertheless, significant differences endure. The BTeV data-driven readout, horizontal and vertical position resolution better than 9 {micro}m with the {+-} 300 mr forward acceptance, and positioning in vacuum and as close as 6 mm from the circulating beams remain unique. These features are driven by the physics goals of the BTeV experiment. Table 2 demonstrates that the vertex trigger performance made possible by these features is requisite for a very large fraction of the B meson decay physics which is so central to the motivation for BTeV. For most of the physics quantities of interest listed in the table, the vertex trigger is essential. The performance of the BTeV pixel detector may be summarized by looking at particular physics examples; e.g., the B{sub s} meson decay B{sub s} {yields} D{sub s}{sup -} K{sup +}. For that decay, studies using GEANT3 simulations provide quantitative measures of performance. For example, the separation between the B{sub s} decay point and the primary proton

  3. Dielectric micro-resonator-based opto-mechanical systems for sensing applications

    NASA Astrophysics Data System (ADS)

    Ali, Amir Roushdy

    In recent years, whispering gallery mode (WGM), or morphology dependent optical resonances (MDR) of dielectric micro-resonators have attracted interest with proposed applications in a wide range of areas due to the high optical quality factors, Q, they can exhibit (reaching ~ 10. 9 for silica spheres). Micro-resonator WGMs have been used in applications that include those in spectroscopy, micro-cavity laser technology, optical communications (switching, filtering and multiplexing), sensors technologies and even chemical and biological sensing. The WGM of these dielectric micro-resonators are highly sensitive to morphological changes (such as the size, shape, or refractive index) of the resonance cavity and hence, can be tuned by causing a minute change in the physical condition of the surrounding. In this dissertation, we have been creating opto-mechanical systems, which at their most basic, are extraordinarily sensitive sensors. One of the ultimate goals of this dissertation is to develop sensors capable of detecting the extremely small electric field changes. To improve the performance of the sensors, we couple a polymer cantilever beam to a dielectric micro-resonator. The eventual use of such ultra sensitive electric filed sensors could include neural-machine interfaces for advanced prosthetics devices. The work presented here includes a basic analysis and experimental investigations of the electric field sensitivity and range of micro-resonators of several different materials and geometries followed by the electric field sensor design, testing, and characterization. Also, the effects of angular velocity on the WGM shifts of spherical micro-resonators are also investigated. The elastic deformation that is induced on a spinning resonator due to the centrifugal force may lead to a sufficient shift in the optical resonances and therefore interfering with its desirable operational sensor design. Furthermore, this principle could be used for the development of

  4. SNR improvement for hyperspectral application using frame and pixel binning

    NASA Astrophysics Data System (ADS)

    Rehman, Sami Ur; Kumar, Ankush; Banerjee, Arup

    2016-05-01

    Hyperspectral imaging spectrometer systems are increasingly being used in the field of remote sensing for variety of civilian and military applications. The ability of such instruments in discriminating finer spectral features along with improved spatial and radiometric performance have made such instruments a powerful tool in the field of remote sensing. Design and development of spaceborne hyper spectral imaging spectrometers poses lot of technological challenges in terms of optics, dispersion element, detectors, electronics and mechanical systems. The main factors that define the type of detectors are the spectral region, SNR, dynamic range, pixel size, number of pixels, frame rate, operating temperature etc. Detectors with higher quantum efficiency and higher well depth are the preferred choice for such applications. CCD based Si detectors serves the requirement of high well depth for VNIR band spectrometers but suffers from smear. Smear can be controlled by using CMOS detectors. Si CMOS detectors with large format arrays are available. These detectors generally have smaller pitch and low well depth. Binning technique can be used with available CMOS detectors to meet the large swath, higher resolution and high SNR requirements. Availability of larger dwell time of satellite can be used to bin multiple frames to increase the signal collection even with lesser well depth detectors and ultimately increase the SNR. Lab measurements reveal that SNR improvement by frame binning is more in comparison to pixel binning. Effect of pixel binning as compared to the frame binning will be discussed and degradation of SNR as compared to theoretical value for pixel binning will be analyzed.

  5. Single-pixel optical imaging with compressed reference intensity patterns

    NASA Astrophysics Data System (ADS)

    Chen, Wen; Chen, Xudong

    2015-03-01

    Ghost imaging with single-pixel bucket detector has attracted more and more current attention due to its marked physical characteristics. However, in ghost imaging, a large number of reference intensity patterns are usually required for object reconstruction, hence many applications based on ghost imaging (such as tomography and optical security) may be tedious since heavy storage or transmission is requested. In this paper, we report that the compressed reference intensity patterns can be used for object recovery in computational ghost imaging (with single-pixel bucket detector), and object verification can be further conducted. Only a small portion (such as 2.0% pixels) of each reference intensity pattern is used for object reconstruction, and the recovered object is verified by using nonlinear correlation algorithm. Since statistical characteristic and speckle averaging property are inherent in ghost imaging, sidelobes or multiple peaks can be effectively suppressed or eliminated in the nonlinear correlation outputs when random pixel positions are selected from each reference intensity pattern. Since pixel positions can be randomly selected from each 2D reference intensity pattern (such as total measurements of 20000), a large key space and high flexibility can be generated when the proposed method is applied for authenticationbased cryptography. When compressive sensing is used to recover the object with a small number of measurements, the proposed strategy could still be feasible through further compressing the recorded data (i.e., reference intensity patterns) followed by object verification. It is expected that the proposed method not only compresses the recorded data and facilitates the storage or transmission, but also can build up novel capability (i.e., classical or quantum information verification) for ghost imaging.

  6. Minimum Variance Approaches to Ultrasound Pixel-Based Beamforming.

    PubMed

    Nguyen, Nghia Q; Prager, Richard W

    2017-02-01

    We analyze the principles underlying minimum variance distortionless response (MVDR) beamforming in order to integrate it into a pixel-based algorithm. There is a challenge posed by the low echo signal-to-noise ratio (eSNR) when calculating beamformer contributions at pixels far away from the beam centreline. Together with the well-known scarcity of samples for covariance matrix estimation, this reduces the beamformer performance and degrades the image quality. To address this challenge, we implement the MVDR algorithm in two different ways. First, we develop the conventional minimum variance pixel-based (MVPB) beamformer that performs the MVDR after the pixel-based superposition step. This involves a combination of methods in the literature, extended over multiple transmits to increase the eSNR. Then we propose the coherent MVPB beamformer, where the MVDR is applied to data within individual transmits. Based on pressure field analysis, we develop new algorithms to improve the data alignment and matrix estimation, and hence overcome the low-eSNR issue. The methods are demonstrated on data acquired with an ultrasound open platform. The results show the coherent MVPB beamformer substantially outperforms the conventional MVPB in a series of experiments, including phantom and in vivo studies. Compared to the unified pixel-based beamformer, the newest delay-and-sum algorithm in [1], the coherent MVPB performs well on regions that conform to the diffuse scattering assumptions on which the minimum variance principles are based. It produces less good results for parts of the image that are dominated by specular reflections.

  7. Dependent video coding using a tree representation of pixel dependencies

    NASA Astrophysics Data System (ADS)

    Amati, Luca; Valenzise, Giuseppe; Ortega, Antonio; Tubaro, Stefano

    2011-09-01

    Motion-compensated prediction induces a chain of coding dependencies between pixels in video. In principle, an optimal selection of encoding parameters (motion vectors, quantization parameters, coding modes) should take into account the whole temporal horizon of a GOP. However, in practical coding schemes, these choices are made on a frame-by-frame basis, thus with a possible loss of performance. In this paper we describe a tree-based model for pixelwise coding dependencies: each pixel in a frame is the child of a pixel in a previous reference frame. We show that some tree structures are more favorable than others from a rate-distortion perspective, e.g., because they entail a large descendance of pixels which are well predicted from a common ancestor. In those cases, a higher quality has to be assigned to pixels at the top of such trees. We promote the creation of these structures by adding a special discount term to the conventional Lagrangian cost adopted at the encoder. The proposed model can be implemented through a double-pass encoding procedure. Specifically, we devise heuristic cost functions to drive the selection of quantization parameters and of motion vectors, which can be readily implemented into a state-of-the-art H.264/AVC encoder. Our experiments demonstrate that coding efficiency is improved for video sequences with low motion, while there are no apparent gains for more complex motion. We argue that this is due to both the presence of complex encoder features not captured by the model, and to the complexity of the source to be encoded.

  8. A new data acquisition system for the CMS Phase 1 pixel detector

    NASA Astrophysics Data System (ADS)

    Kornmayer, A.

    2016-12-01

    A new pixel detector will be installed in the CMS experiment during the extended technical stop of the LHC at the beginning of 2017. The new pixel detector, built from four layers in the barrel region and three layers on each end of the forward region, is equipped with upgraded front-end readout electronics, specifically designed to handle the high particle hit rates created in the LHC environment. The DAQ back-end was entirely redesigned to handle the increased number of readout channels, the higher data rates per channel and the new digital data format. Based entirely on the microTCA standard, new front-end controller (FEC) and front-end driver (FED) cards have been developed, prototyped and produced with custom optical link mezzanines mounted on the FC7 AMC and custom firmware. At the same time as the new detector is being assembled, the DAQ system is set up and its integration into the CMS central DAQ system tested by running the pilot blade detector already installed in CMS. This work describes the DAQ system, integration tests and gives an outline for the activities up to commissioning the final system at CMS in 2017.

  9. Microlens performance limits in sub-2mum pixel CMOS image sensors.

    PubMed

    Huo, Yijie; Fesenmaier, Christian C; Catrysse, Peter B

    2010-03-15

    CMOS image sensors with smaller pixels are expected to enable digital imaging systems with better resolution. When pixel size scales below 2 mum, however, diffraction affects the optical performance of the pixel and its microlens, in particular. We present a first-principles electromagnetic analysis of microlens behavior during the lateral scaling of CMOS image sensor pixels. We establish for a three-metal-layer pixel that diffraction prevents the microlens from acting as a focusing element when pixels become smaller than 1.4 microm. This severely degrades performance for on and off-axis pixels in red, green and blue color channels. We predict that one-metal-layer or backside-illuminated pixels are required to extend the functionality of microlenses beyond the 1.4 microm pixel node.

  10. Structure and opto-electrochemical properties of ZnO nanowires grown on n-Si substrate.

    PubMed

    Ladanov, Mikhail; Ram, Manoj K; Matthews, Garrett; Kumar, Ashok

    2011-07-19

    Zinc oxide (ZnO) nanostructures have attracted great attention as a promising functional material with unique properties suitable for applications in UV lasers, light emitting diodes, field emission devices, sensors, field effect transistors, and solar cells. In the present work, ZnO nanowires have been synthesized on an n-type Si substrate using a hydrothermal method where surfactant acted as a modifying and protecting agent. The surface morphology, electrochemical properties, and opto-electrochemical properties of ZnO nanowires are investigated by using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), cyclic voltammetry, and impedance spectroscopy techniques. The cycling characteristics and rate capability of the ZnO nanowires are explored through electrochemical studies performed under varying electrolytes. The photo response is observed using UV radiation. It is demonstrated that crystallinity, particle size, and morphology all play significant roles in the electrochemical performance of the ZnO electrodes.

  11. Opto-electronic device for frequency standard generation and terahertz-range optical demodulation based on quantum interference

    DOEpatents

    Georgiades, Nikos P.; Polzik, Eugene S.; Kimble, H. Jeff

    1999-02-02

    An opto-electronic system and technique for comparing laser frequencies with large frequency separations, establishing new frequency standards, and achieving phase-sensitive detection at ultra high frequencies. Light responsive materials with multiple energy levels suitable for multi-photon excitation are preferably used for nonlinear mixing via quantum interference of different excitation paths affecting a common energy level. Demodulation of a carrier with a demodulation frequency up to 100's THZ can be achieved for frequency comparison and phase-sensitive detection. A large number of materials can be used to cover a wide spectral range including the ultra violet, visible and near infrared regions. In particular, absolute frequency measurement in a spectrum from 1.25 .mu.m to 1.66 .mu.m for fiber optics can be accomplished with a nearly continuous frequency coverage.

  12. Opto-electronic device for frequency standard generation and terahertz-range optical demodulation based on quantum interference

    DOEpatents

    Georgiades, N.P.; Polzik, E.S.; Kimble, H.J.

    1999-02-02

    An opto-electronic system and technique for comparing laser frequencies with large frequency separations, establishing new frequency standards, and achieving phase-sensitive detection at ultra high frequencies are disclosed. Light responsive materials with multiple energy levels suitable for multi-photon excitation are preferably used for nonlinear mixing via quantum interference of different excitation paths affecting a common energy level. Demodulation of a carrier with a demodulation frequency up to 100`s THZ can be achieved for frequency comparison and phase-sensitive detection. A large number of materials can be used to cover a wide spectral range including the ultra violet, visible and near infrared regions. In particular, absolute frequency measurement in a spectrum from 1.25 {micro}m to 1.66 {micro}m for fiber optics can be accomplished with a nearly continuous frequency coverage. 7 figs.

  13. Developing dual-beam laser Doppler interferometry system for opto-piezoelectric materials based ultrasonic parking sensors and optofluidics sensors

    NASA Astrophysics Data System (ADS)

    Lai, Po-Cheng; Lee, Chih-Kung

    2014-03-01

    Adopting opto-piezoelectric materials, which utilized optical illumination pattern to effect the spatial force distribution induced by piezoelectric materials, to ultrasonic parking sensors and optofluidic chips represent a new research direction in industrial sub-system development. To accommodate performance requirements include wide bandwidth, ultrahigh precision, non-contact measurement mode, linear and angular measurement, etc. associated with the evaluation of the above-mentioned systems, a laser Doppler interferometer was implemented to facilitate the system development. The completely orthogonal alignment design configuration, system performance verified, signal processing algorithms developed as well as the experimental results obtained were all discussed in this paper. Emphasis is on the experimental data obtained from the interferometer and the design changes developed based on the metrology outcome. The system performance improvements induced by the experimental verification achieved by the interferometer were discussed in detail.

  14. High-precision opto-mechanical lens system for space applications assembled by innovative local soldering technique

    NASA Astrophysics Data System (ADS)

    Ribes, P.; Koechlin, C.; Burkhardt, T.; Hornaff, M.; Burkhardt, D.; Kamm, A.; Gramens, S.; Beckert, E.; Fiault, G.; Eberhardt, R.; Tünnermann, A.

    2016-02-01

    Solder joining using metallic solder alloys is an alternative to adhesive bonding. Laser-based soldering processes are especially well suited for the joining of optical components made of fragile and brittle materials such as glasses, ceramics and optical crystals. This is due to a localized and minimized input of thermal energy. Solderjet bumping technology has been used to assemble a lens mount breadboard taking as input specifications the requirements found for the optical beam expander for the European Space Agency (ESA) EarthCare Mission. The silica lens and a titanium barrel have been designed and assembled with this technology in order to withstand the stringent mission demands; handling high mechanical and thermal loads without losing its optical performances. Finally a high-precision opto-mechanical lens mount has been assembled with a minimal localized stress (<1 MPa) showing outstanding performances in terms of wave-front error measurements and beam depolarization ratio before and after environmental tests.

  15. Improving the opto-microwave performance of SiGe/Si phototransistor through edge-illuminated structure

    NASA Astrophysics Data System (ADS)

    Tegegne, Z. G.; Viana, C.; Polleux, J. L.; Grzeskowiak, M.; Richalot, E.

    2016-03-01

    This paper demonstrates the experimental study of edge and top illuminated SiGe phototransistors (HPT) implemented using the existing industrial SiGe2RF Telefunken GmbH BiCMOS technology for opto-microwave (OM) applications using 850nm Multi-Mode Fibers (MMF). Its technology and structure are described. Two different optical window size HPTs with top illumination (5x5μm2, 10x10μm2) and an edge illuminated HPTs having 5μm x5μm size are presented and compared. A two-step post fabrication process was used to create an optical access on the edge of the HPT for lateral illumination with a lensed MMF through simple polishing and dicing techniques. We perform Opto-microwave Scanning Near-field Optical Microscopy (OM-SNOM) analysis on edge and top illuminated HPTs in order to observe the fastest and the highest sensitive regions of the HPTs. This analysis also allows understanding the parasitic effect from the substrate, and thus draws a conclusion on the design aspect of SiGe/Si HPT. A low frequency OM responsivity of 0.45A/W and a cutoff frequency, f-3dB, of 890MHz were measured for edge illuminated HPT. Compared to the top illuminated HPT of the same size, the edge illuminated HPT improves the f-3dB by a factor of more than two and also improves the low frequency responsivity by a factor of more than four. These results demonstrate that a simple etched HPT is still enough to achieve performance improvements compared to the top illuminated HPT without requiring a complex coupling structure. Indeed, it also proves the potential of edge coupled SiGe HPT in the ultra-low-cost silicon based optoelectronics circuits with a new approach of the optical packaging and system integration to 850nm MMF.

  16. Land cover mapping at sub-pixel scales

    NASA Astrophysics Data System (ADS)

    Makido, Yasuyo Kato

    One of the biggest drawbacks of land cover mapping from remotely sensed images relates to spatial resolution, which determines the level of spatial details depicted in an image. Fine spatial resolution images from satellite sensors such as IKONOS and QuickBird are now available. However, these images are not suitable for large-area studies, since a single image is very small and therefore it is costly for large area studies. Much research has focused on attempting to extract land cover types at sub-pixel scale, and little research has been conducted concerning the spatial allocation of land cover types within a pixel. This study is devoted to the development of new algorithms for predicting land cover distribution using remote sensory imagery at sub-pixel level. The "pixel-swapping" optimization algorithm, which was proposed by Atkinson for predicting sub-pixel land cover distribution, is investigated in this study. Two limitations of this method, the arbitrary spatial range value and the arbitrary exponential model of spatial autocorrelation, are assessed. Various weighting functions, as alternatives to the exponential model, are evaluated in order to derive the optimum weighting function. Two different simulation models were employed to develop spatially autocorrelated binary class maps. In all tested models, Gaussian, Exponential, and IDW, the pixel swapping method improved classification accuracy compared with the initial random allocation of sub-pixels. However the results suggested that equal weight could be used to increase accuracy and sub-pixel spatial autocorrelation instead of using these more complex models of spatial structure. New algorithms for modeling the spatial distribution of multiple land cover classes at sub-pixel scales are developed and evaluated. Three methods are examined: sequential categorical swapping, simultaneous categorical swapping, and simulated annealing. These three methods are applied to classified Landsat ETM+ data that has

  17. A novel CMOS sensor with in-pixel auto-zeroed discrimination for charged particle tracking

    NASA Astrophysics Data System (ADS)

    Degerli, Y.; Guilloux, F.; Orsini, F.

    2014-05-01

    With the aim of developing fast and granular Monolithic Active Pixels Sensors (MAPS) as new charged particle tracking detectors for high energy physics experiments, a new rolling shutter binary pixel architecture concept (RSBPix) with in-pixel correlated double sampling, amplification and discrimination is presented. The discriminator features auto-zeroing in order to compensate process-related transistor mismatches. In order to validate the pixel, a first monolithic CMOS sensor prototype, including a pixel array of 96 × 64 pixels, has been designed and fabricated in the Tower-Jazz 0.18 μm CMOS Image Sensor (CIS) process. Results of laboratory tests are presented.

  18. High throughput optoelectronic smart pixel systems using diffractive optics

    NASA Astrophysics Data System (ADS)

    Chen, Chih-Hao

    1999-12-01

    Recent developments in digital video, multimedia technology and data networks have greatly increased the demand for high bandwidth communication channels and high throughput data processing. Electronics is particularly suited for switching, amplification and logic functions, while optics is more suitable for interconnections and communications with lower energy and crosstalk. In this research, we present the design, testing, integration and demonstration of several optoelectronic smart pixel devices and system architectures. These systems integrate electronic switching/processing capability with parallel optical interconnections to provide high throughput network communication and pipeline data processing. The Smart Pixel Array Cellular Logic processor (SPARCL) is designed in 0.8 m m CMOS and hybrid integrated with Multiple-Quantum-Well (MQW) devices for pipeline image processing. The Smart Pixel Network Interface (SAPIENT) is designed in 0.6 m m GaAs and monolithically integrated with LEDs to implement a highly parallel optical interconnection network. The Translucent Smart Pixel Array (TRANSPAR) design is implemented in two different versions. The first version, TRANSPAR-MQW, is designed in 0.5 m m CMOS and flip-chip integrated with MQW devices to provide 2-D pipeline processing and translucent networking using the Carrier- Sense-MultipleAccess/Collision-Detection (CSMA/CD) protocol. The other version, TRANSPAR-VM, is designed in 1.2 m m CMOS and discretely integrated with VCSEL-MSM (Vertical-Cavity-Surface- Emitting-Laser and Metal-Semiconductor-Metal detectors) chips and driver/receiver chips on a printed circuit board. The TRANSPAR-VM provides an option of using the token ring network protocol in addition to the embedded functions of TRANSPAR-MQW. These optoelectronic smart pixel systems also require micro-optics devices to provide high resolution, high quality optical interconnections and external source arrays. In this research, we describe an innovative

  19. Cooperation and competition in business on example of Internet research of opto-electronic companies

    NASA Astrophysics Data System (ADS)

    Kaliczyńska, Małgorzata

    2006-10-01

    Based on findings from earlier studies which showed that links to academic web sites contain important information, the following study examines the practicability of using co-link data to describe cooperation and competition in optoelec-tronic business. The analysis was based on 32 companies and organizations which were found in an issue of a specialist magazine. For the purpose of the research three search engines - Google, Yahoo! and MSN Search were used. Assuming that a number of co-links to a pair of Web sites is a measure of the similarity between the two companies, the study aims at search for the sets of companies that would be similar to one another. The method applied is the MDS - multidimensional scaling that allows to present results of the analysis on a 2D map.

  20. Compact opto-electronic engine for high-speed compressive sensing

    NASA Astrophysics Data System (ADS)

    Tidman, James; Weston, Tyler; Hewitt, Donna; Herman, Matthew A.; McMackin, Lenore

    2013-09-01

    The measurement efficiency of Compressive Sensing (CS) enables the computational construction of images from far fewer measurements than what is usually considered necessary by the Nyquist- Shannon sampling theorem. There is now a vast literature around CS mathematics and applications since the development of its theoretical principles about a decade ago. Applications include quantum information to optical microscopy to seismic and hyper-spectral imaging. In the application of shortwave infrared imaging, InView has developed cameras based on the CS single-pixel camera architecture. This architecture is comprised of an objective lens to image the scene onto a Texas Instruments DLP® Micromirror Device (DMD), which by using its individually controllable mirrors, modulates the image with a selected basis set. The intensity of the modulated image is then recorded by a single detector. While the design of a CS camera is straightforward conceptually, its commercial implementation requires significant development effort in optics, electronics, hardware and software, particularly if high efficiency and high-speed operation are required. In this paper, we describe the development of a high-speed CS engine as implemented in a lab-ready workstation. In this engine, configurable measurement patterns are loaded into the DMD at speeds up to 31.5 kHz. The engine supports custom reconstruction algorithms that can be quickly implemented. Our work includes optical path design, Field programmable Gate Arrays for DMD pattern generation, and circuit boards for front end data acquisition, ADC and system control, all packaged in a compact workstation.

  1. Efficient defect pixel cluster detection and correction for Bayer CFA image sequences

    NASA Astrophysics Data System (ADS)

    Tajbakhsh, Touraj

    2011-01-01

    Image sensor arrays may have defect pixels, either originating from manufacturing or being developed over the lifetime of the image sensor array. Continuous defect pixel detection and correction performing during camera runtime is desirable. On-the-fly detection and correction is challenging since edges and high-frequency image content might get identified as defect pixel regions and intact pixels become corrupted during defect pixel replacement. We propose a table-based detection and correction method which by and by fills the non-volatile table during normal camera operation. In this work we model defect pixels and pixel clusters to be stuck to fixed values or at least fixed to a narrow value range whereas the local neighborhood of these pixels indicate a normal behavior. The idea is to temporally observe the value ranges of small group of pixels (e.g. 4x4 pixel blocks) and to decide about their defective condition depending on their variability with respect to their neighbor pixels. Our method is computationally efficient, requires no frame buffer, requires modest memory, and therefore is appropriate to operate in line-buffer based image signal processing (ISP) systems. Our results indicate high reliability in terms of detection rates and robustness against high-frequency image content. As part of the defect pixel replacement system we also propose a simple and efficient defect pixel correction method based on the mean of medians operating on the Bayer CFA image domain.

  2. Current progress on pixel level packaging for uncooled IRFPA

    NASA Astrophysics Data System (ADS)

    Dumont, G.; Rabaud, W.; Yon, J.-J.; Carle, L.; Goudon, V.; Vialle, C.; Becker, Sébastien; Hamelin, Antoine; Arnaud, A.

    2012-06-01

    Vacuum packaging is definitely a major cost driver for uncooled IRFPA and a technological breakthrough is still expected to comply with the very low cost infrared camera market. To address this key issue, CEA-LETI is developing a Pixel Level Packaging (PLP) technology which basically consists in capping each pixel under vacuum in the direct continuation of the wafer level bolometer process. Previous CEA-LETI works have yet shown the feasibility of PLP based microbolometers that exhibit the required thermal insulation and vacuum achievement. CEA-LETI is still pushing the technology which has been now applied for the first time on a CMOS readout circuit. The paper will report on the recent progress obtained on PLP technology with particular emphasis on the optical efficiency of the PLP arrangement compared to the traditional microbolometer packaging. Results including optical performances, aging studies and compatibility with CMOS readout circuit are extensively presented.

  3. Distance measurement based on pixel variation of CCD images.

    PubMed

    Hsu, Chen-Chien; Lu, Ming-Chih; Wang, Wei-Yen; Lu, Yin-Yu

    2009-10-01

    This paper presents a distance measurement method based on pixel number variation of CCD images by referencing to two arbitrarily designated points in the image frames. By establishing a relationship between the displacement of the camera movement along the photographing direction and the difference in pixel count between reference points in the images, the distance from an object can be calculated via the proposed method. To integrate the measuring functions into digital cameras, a circuit design implementing the proposed measuring system in selecting reference points, measuring distance, and displaying measurement results on CCD panel of the digital camera is proposed in this paper. In comparison to pattern recognition or image analysis methods, the proposed measuring approach is simple and straightforward for practical implementation into digital cameras. To validate the performance of the proposed method, measurement results using the proposed method and ultrasonic rangefinders are also presented in this paper.

  4. Sensor Development and Readout Prototyping for the STAR Pixel Detector

    SciTech Connect

    Greiner, L.; Anderssen, E.; Matis, H.S.; Ritter, H.G.; Stezelberger, T.; Szelezniak, M.; Sun, X.; Vu, C.; Wieman, H.

    2009-01-14

    The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) is designing a new vertex detector. The purpose of this upgrade detector is to provide high resolution pointing to allow for the direct topological reconstruction of heavy flavor decays such as the D{sup 0} by finding vertices displaced from the collision vertex by greater than 60 microns. We are using Monolithic Active Pixel Sensor (MAPS) as the sensor technology and have a coupled sensor development and readout system plan that leads to a final detector with a <200 {micro}s integration time, 400 M pixels and a coverage of -1 < {eta} < 1. We present our coupled sensor and readout development plan and the status of the prototyping work that has been accomplished.

  5. Pixel extraction based integral imaging with controllable viewing direction

    NASA Astrophysics Data System (ADS)

    Ji, Chao-Chao; Deng, Huan; Wang, Qiong-Hua

    2012-09-01

    We propose pixel extraction based integral imaging with a controllable viewing direction. The proposed integral imaging can provide viewers three-dimensional (3D) images in a very small viewing angle. The viewing angle and the viewing direction of the reconstructed 3D images are controlled by the pixels extracted from an elemental image array. Theoretical analysis and a 3D display experiment of the viewing direction controllable integral imaging are carried out. The experimental results verify the correctness of the theory. A 3D display based on the integral imaging can protect the viewer’s privacy and has huge potential for a television to show multiple 3D programs at the same time.

  6. Pixel detector system development at Diamond Light Source

    NASA Astrophysics Data System (ADS)

    Marchal, J.; Horswell, I.; Gimenez, E. N.; Tartoni, N.

    2010-10-01

    Hybrid pixel detectors consisting of an array of silicon photodiodes bump-bonded to CMOS read-out chips provide high signal-to-noise ratio and high dynamic range compared to CCD-based detectors and Image Plates. These detector features are important for SAXS experiments where a wide range of intensities are present in the images. For time resolved SAXS experiments, high frame rates are compulsory. The latest CMOS read-out chip developed by the MEDIPIX collaboration provides high frame rate and continuous acquisition mode. A read-out system for an array of MEDIPIX3 sensors is under development at Diamond Light Source. This system will support a full resolution frame rate of 1 kHz at a pixel counter depth of 12-bit and a frame rate of 30 kHz at a counter depth of 1 bit. Details concerning system design and MEDIPIX sensors characterization are presented.

  7. CMS Pixel Detector design for HL-LHC

    NASA Astrophysics Data System (ADS)

    Migliore, E.

    2016-12-01

    The LHC machine is planning an upgrade program which will smoothly bring the luminosity to about 7.5×1034cm-2s-1 in 2028, to possibly reach an integrated luminosity of 3000 fb-1 by the end of 2037. This High Luminosity scenario, HL-LHC, will present new challenges in higher data rates and increased radiation. In order to maintain its physics reach the CMS collaboration has undertaken a preparation program of the detector known as Phase-2 upgrade. The CMS Phase-2 Pixel upgrade will require a high bandwidth readout system and high radiation tolerance for sensors and on-detector ASICs. Several technologies for the upgrade sensors are being studied. Serial powering schemes are under consideration to accommodate significant constraints on the system. These prospective designs, as well as new layout geometries that include very forward pixel discs, will be presented together with performance estimation.

  8. Sub-pixel resolution with the Multispectral Thermal Imager (MTI).

    SciTech Connect

    Decker, Max Louis; Smith, Jody Lynn; Nandy, Prabal

    2003-06-01

    The Multispectral Thermal Imager Satellite (MTI) has been used to test a sub-pixel sampling technique in an effort to obtain higher spatial frequency imagery than that of its original design. The MTI instrument is of particular interest because of its infrared detectors. In this spectral region, the detector size is traditionally the limiting factor in determining the satellite's ground sampling distance (GSD). Additionally, many over-sampling techniques require flexible command and control of the sensor and spacecraft. The MTI sensor is well suited for this task, as it is the only imaging system on the MTI satellite bus. In this super-sampling technique, MTI is maneuvered such that the data are collected at sub-pixel intervals on the ground. The data are then processed using a deconvolution algorithm using in-scene measured point spread functions (PSF) to produce an image with synthetically-boosted GSD.

  9. Compressive holography with a single-pixel detector.

    PubMed

    Clemente, Pere; Durán, Vicente; Tajahuerce, Enrique; Andrés, Pedro; Climent, Vicent; Lancis, Jesús

    2013-07-15

    This Letter develops a framework for digital holography at optical wavelengths by merging phase-shifting interferometry with single-pixel optical imaging based on compressive sensing. The field diffracted by an input object is sampled by Hadamard patterns with a liquid crystal spatial light modulator. The concept of a single-pixel camera is then adapted to perform interferometric imaging of the sampled diffraction pattern by using a Mach-Zehnder interferometer. Phase-shifting techniques together with the application of a backward light propagation algorithm allow the complex amplitude of the object under scrutiny to be resolved. A proof-of-concept experiment evaluating the phase distribution of an ophthalmic lens with compressive phase-shifting holography is provided.

  10. Using Trained Pixel Classifiers to Select Images of Interest

    NASA Technical Reports Server (NTRS)

    Mazzoni, D.; Wagstaff, K.; Castano, R.

    2004-01-01

    We present a machine-learning-based approach to ranking images based on learned priorities. Unlike previous methods for image evaluation, which typically assess the value of each image based on the presence of predetermined specific features, this method involves using two levels of machine-learning classifiers: one level is used to classify each pixel as belonging to one of a group of rather generic classes, and another level is used to rank the images based on these pixel classifications, given some example rankings from a scientist as a guide. Initial results indicate that the technique works well, producing new rankings that match the scientist's rankings significantly better than would be expected by chance. The method is demonstrated for a set of images collected by a Mars field-test rover.

  11. New SOFRADIR 10μm pixel pitch infrared products

    NASA Astrophysics Data System (ADS)

    Lefoul, X.; Pere-Laperne, N.; Augey, T.; Rubaldo, L.; Aufranc, Sébastien; Decaens, G.; Ricard, N.; Mazaleyrat, E.; Billon-Lanfrey, D.; Gravrand, Olivier; Bisotto, Sylvette

    2014-10-01

    Recent advances in miniaturization of IR imaging technology have led to a growing market for mini thermal-imaging sensors. In that respect, Sofradir development on smaller pixel pitch has made much more compact products available to the users. When this competitive advantage is mixed with smaller coolers, made possible by HOT technology, we achieved valuable reductions in the size, weight and power of the overall package. At the same time, we are moving towards a global offer based on digital interfaces that provides our customers simplifications at the IR system design process while freeing up more space. This paper discusses recent developments on hot and small pixel pitch technologies as well as efforts made on compact packaging solution developed by SOFRADIR in collaboration with CEA-LETI.

  12. Image pixel device using integrated organic electronic components

    NASA Astrophysics Data System (ADS)

    Swathi, K.; Narayan, K. S.

    2016-11-01

    We report a solution processed, monolithically integrated device similar to an imaging pixel element used in complementary metal-oxide semiconductor (CMOS) based cameras. This integrated pixel essentially consists of a pair of organic photodiode (OPD) and organic field effect transistor (OFET). The signal generated by the light responsive OPD drives the OFET to different output states to quantify the light intensity. The prerequisite of a low operating voltage OFET (<2 V) was achieved using a bottom-gate, top-contact OFET consisting of a high mobility polymer semiconductor and a self-assembled hybrid dielectric layer. A bulk heterojunction blend was used as the photo-active layer in the OPD along with suitable buffer layers for charge extraction. The material parameters were optimized to realize a suitable structure which clearly demonstrated the interplay of the OPD and OFET operations, thereby forming a roadmap for all-organic CMOS arrays.

  13. Measurement results of DIPIX pixel sensor developed in SOI technology

    NASA Astrophysics Data System (ADS)

    Ahmed, Mohammed Imran; Arai, Yasuo; Idzik, Marek; Kapusta, Piotr; Miyoshi, Toshinobu; Turala, Michal

    2013-08-01

    The development of integration type pixel detectors presents interest for physics communities because it brings optimization of design, simplicity of production-which means smaller cost, and reduction of detector material budget. During the last decade a lot of research and development activities took place in the field of CMOS Silicon-On-Insulator (SOI) technology resulting in improvement in wafer size, wafer resistivity and MIM capacitance. Several ideas have been tested successfully and are gradually entering into the application phase. Some of the novel concepts exploring SOI technology are pursued at KEK; several prototypes of dual mode integration type pixel (DIPIX) have been recently produced and described. This report presents initial test results of some of the prototypes including tests obtained with the infrared laser beams and Americium (Am-241) source. The Equivalent Noise Charge (ENC) of 86 e - has been measured. The measured performance demonstrates that SOI technology is a feasible choice for future applications.

  14. Digital pixel sensor array with logarithmic delta-sigma architecture.

    PubMed

    Mahmoodi, Alireza; Li, Jing; Joseph, Dileepan

    2013-08-16

    Like the human eye, logarithmic image sensors achieve wide dynamic range easily at video rates, but, unlike the human eye, they suffer from low peak signal-to-noise-and-distortion ratios (PSNDRs). To improve the PSNDR, we propose integrating a delta-sigma analog-to-digital converter (ADC) in each pixel. An image sensor employing this architecture is designed, built and tested in 0.18 micron complementary metal-oxide-semiconductor (CMOS) technology. It achieves a PSNDR better than state-of-the-art logarithmic sensors and comparable to the human eye. As the approach concerns an array of many ADCs, we use a small-area low-power delta-sigma design. For scalability, each pixel has its own decimator. The prototype is compared to a variety of other image sensors, linear and nonlinear, from industry and academia.

  15. Performance studies of Micro Pixel Chamber for the ATLAS upgrade

    NASA Astrophysics Data System (ADS)

    Komai, H.; Ochi, A.; Homma, Y.; Edo, Y.; Yamaguchi, T.

    2013-03-01

    The Micro Pixel Chamber (μ-PIC) is being developed as a muon chamber of the ATLAS experiment in an HL-LHC environment. In the ATLAS muon system, a high flux of fast neutron background causes instability operation of the detectors. We performed neutron irradiation tests with μ-PIC to optimize the operation gas and detector structure. In addition, we studied neutron interactions with the detector, in order to understand the effect of fast neutrons.

  16. Planar slim-edge pixel sensors for the ATLAS upgrades

    NASA Astrophysics Data System (ADS)

    Altenheiner, S.; Goessling, C.; Jentzsch, J.; Klingenberg, R.; Lapsien, T.; Muenstermann, D.; Rummler, A.; Troska, G.; Wittig, T.

    2012-02-01

    The ATLAS detector at CERN is a general-purpose experiment at the Large Hadron Collider (LHC). The ATLAS Pixel Detector is the innermost tracking detector of ATLAS and requires a sufficient level of hermeticity to achieve superb track reconstruction performance. The current planar n-type pixel sensors feature a pixel matrix of n+-implantations which is (on the opposite p-side) surrounded by so-called guard rings to reduce the high voltage stepwise towards the cutting edge and an additional safety margin. Because of the inactive region around the active area, the sensor modules have been shingled on top of each other's edge which limits the thermal performance and adds complexity in the present detector. The first upgrade phase of the ATLAS pixel detector will consist of the insertable b-layer (IBL), an additional b-layer which will be inserted into the present detector in 2013. Several changes in the sensor design with respect to the existing detector had to be applied to comply with the IBL's specifications and are described in detail. A key issue for the ATLAS upgrades is a flat arrangement of the sensors. To maintain the required level of hermeticity in the detector, the inactive sensor edges have to be reduced to minimize the dead space between the adjacent detector modules. Unirradiated and irradiated sensors with the IBL design have been operated in test beams to study the efficiency performance in the sensor edge region and it was found that the inactive edge width could be reduced from 1100 μm to less than 250 μm.

  17. A CMOS In-Pixel CTIA High Sensitivity Fluorescence Imager

    PubMed Central

    Murari, Kartikeya; Etienne-Cummings, Ralph; Thakor, Nitish; Cauwenberghs, Gert

    2012-01-01

    Traditionally, charge coupled device (CCD) based image sensors have held sway over the field of biomedical imaging. Complementary metal oxide semiconductor (CMOS) based imagers so far lack sensitivity leading to poor low-light imaging. Certain applications including our work on animal-mountable systems for imaging in awake and unrestrained rodents require the high sensitivity and image quality of CCDs and the low power consumption, flexibility and compactness of CMOS imagers. We present a 132×124 high sensitivity imager array with a 20.1 μm pixel pitch fabricated in a standard 0.5 μ CMOS process. The chip incorporates n-well/p-sub photodiodes, capacitive transimpedance amplifier (CTIA) based in-pixel amplification, pixel scanners and delta differencing circuits. The 5-transistor all-nMOS pixel interfaces with peripheral pMOS transistors for column-parallel CTIA. At 70 fps, the array has a minimum detectable signal of 4 nW/cm2 at a wavelength of 450 nm while consuming 718 μA from a 3.3 V supply. Peak signal to noise ratio (SNR) was 44 dB at an incident intensity of 1 μW/cm2. Implementing 4×4 binning allowed the frame rate to be increased to 675 fps. Alternately, sensitivity could be increased to detect about 0.8 nW/cm2 while maintaining 70 fps. The chip was used to image single cell fluorescence at 28 fps with an average SNR of 32 dB. For comparison, a cooled CCD camera imaged the same cell at 20 fps with an average SNR of 33.2 dB under the same illumination while consuming over a watt. PMID:23136624

  18. Characterization of indium and solder bump bonding for pixel detectors

    SciTech Connect

    Selcuk Cihangir and Simon Kwan

    2000-09-28

    A review of different bump-bonding processes used for pixel detectors is given. A large scale test on daisy-chained components from two vendors has been carried out at Fermilab to characterize the yield of these processes. The vendors are Advanced Interconnect Technology Ltd. (AIT) of Hong Kong and MCNC in North Carolina, US. The results from this test are presented and technical challenges encountered are discussed.

  19. Validity Assessment of Pixel Linear Spectral Mixing Through Laboratory Measurements

    NASA Astrophysics Data System (ADS)

    Mobasheri, M. R.; Dehnavi, S.; Maghsoudi, Y.

    2015-12-01

    In order to understand the characteristics of the data collected by hyperspectral imaging systems, it is important to discuss the physics behind the scene radiance field incident on the imaging system. A dominant effect in hyperspectral remote sensing is the mixing of radiant energies contributed from different materials present in a given pixel. The basic assumption of mixture modelling is that within a given scene, the surface is covered by a small number of distinct materials that have relatively constant spectral properties. It is most common to assume that the radiance reflected by different materials in a pixel can spectrally combine in a linear additive manner to produce the pixel radiance/reflectance, even when that might not be the case e.g. where the mixing process leads to nonlinear combinations of the radiance and where the linear assumption fails to hold. This can occur where there is significant relative three-dimensional structure within a given pixel. Without detailed knowledge of the dimensional structure, it can be very difficult to correctly ``un-mix'' the contributions of the various materials. This work aims to evaluate the correctness of the linear assumption in the mixture modelling using some laboratory measurements. Study was conducted using some sheets made of cellulose materials of different colours in 400-800 nm spectral range. Experimental results have shown that a correction term must be applied to the gains and offsets in the linear model. The obtained results can be extended to satellite sensors that acquire images in the above mentioned spectral range.

  20. Sub-pixel spatial resolution wavefront phase imaging

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip (Inventor); Mooney, James T. (Inventor)

    2012-01-01

    A phase imaging method for an optical wavefront acquires a plurality of phase images of the optical wavefront using a phase imager. Each phase image is unique and is shifted with respect to another of the phase images by a known/controlled amount that is less than the size of the phase imager's pixels. The phase images are then combined to generate a single high-spatial resolution phase image of the optical wavefront.

  1. Active pixel imagers incorporating pixel-level amplifiers based on polycrystalline-silicon thin-film transistors.

    PubMed

    El-Mohri, Youcef; Antonuk, Larry E; Koniczek, Martin; Zhao, Qihua; Li, Yixin; Street, Robert A; Lu, Jeng-Ping

    2009-07-01

    Active matrix, flat-panel imagers (AMFPIs) employing a 2D matrix of a-Si addressing TFTs have become ubiquitous in many x-ray imaging applications due to their numerous advantages. However, under conditions of low exposures and/or high spatial resolution, their signal-to-noise performance is constrained by the modest system gain relative to the electronic additive noise. In this article, a strategy for overcoming this limitation through the incorporation of in-pixel amplification circuits, referred to as active pixel (AP) architectures, using polycrystalline-silicon (poly-Si) TFTs is reported. Compared to a-Si, poly-Si offers substantially higher mobilities, enabling higher TFT currents and the possibility of sophisticated AP designs based on both n- and p-channel TFTs. Three prototype indirect detection arrays employing poly-Si TFTs and a continuous a-Si photodiode structure were characterized. The prototypes consist of an array (PSI-1) that employs a pixel architecture with a single TFT, as well as two arrays (PSI-2 and PSI-3) that employ AP architectures based on three and five TFTs, respectively. While PSI-1 serves as a reference with a design similar to that of conventional AMFPI arrays, PSI-2 and PSI-3 incorporate additional in-pixel amplification circuitry. Compared to PSI-1, results of x-ray sensitivity demonstrate signal gains of approximately 10.7 and 20.9 for PSI-2 and PSI-3, respectively. These values are in reasonable agreement with design expectations, demonstrating that poly-Si AP circuits can be tailored to provide a desired level of signal gain. PSI-2 exhibits the same high levels of charge trapping as those observed for PSI-1 and other conventional arrays employing a continuous photodiode structure. For PSI-3, charge trapping was found to be significantly lower and largely independent of the bias voltage applied across the photodiode. MTF results indicate that the use of a continuous photodiode structure in PSI-1, PSI-2, and PSI-3 results in

  2. Active pixel imagers incorporating pixel-level amplifiers based on polycrystalline-silicon thin-film transistors

    PubMed Central

    El-Mohri, Youcef; Antonuk, Larry E.; Koniczek, Martin; Zhao, Qihua; Li, Yixin; Street, Robert A.; Lu, Jeng-Ping

    2009-01-01

    Active matrix, flat-panel imagers (AMFPIs) employing a 2D matrix of a-Si addressing TFTs have become ubiquitous in many x-ray imaging applications due to their numerous advantages. However, under conditions of low exposures and∕or high spatial resolution, their signal-to-noise performance is constrained by the modest system gain relative to the electronic additive noise. In this article, a strategy for overcoming this limitation through the incorporation of in-pixel amplification circuits, referred to as active pixel (AP) architectures, using polycrystalline-silicon (poly-Si) TFTs is reported. Compared to a-Si, poly-Si offers substantially higher mobilities, enabling higher TFT currents and the possibility of sophisticated AP designs based on both n- and p-channel TFTs. Three prototype indirect detection arrays employing poly-Si TFTs and a continuous a-Si photodiode structure were characterized. The prototypes consist of an array (PSI-1) that employs a pixel architecture with a single TFT, as well as two arrays (PSI-2 and PSI-3) that employ AP architectures based on three and five TFTs, respectively. While PSI-1 serves as a reference with a design similar to that of conventional AMFPI arrays, PSI-2 and PSI-3 incorporate additional in-pixel amplification circuitry. Compared to PSI-1, results of x-ray sensitivity demonstrate signal gains of ∼10.7 and 20.9 for PSI-2 and PSI-3, respectively. These values are in reasonable agreement with design expectations, demonstrating that poly-Si AP circuits can be tailored to provide a desired level of signal gain. PSI-2 exhibits the same high levels of charge trapping as those observed for PSI-1 and other conventional arrays employing a continuous photodiode structure. For PSI-3, charge trapping was found to be significantly lower and largely independent of the bias voltage applied across the photodiode. MTF results indicate that the use of a continuous photodiode structure in PSI-1, PSI-2, and PSI-3 results in optical fill

  3. Construction of the Phase I Forward Pixel Detector

    NASA Astrophysics Data System (ADS)

    Neylon, Ashton; Bartek, Rachel

    2017-01-01

    The silicon pixel detector is the innermost component of the CMS tracking system, providing high precision space point measurements of charged particle trajectories. The original CMS detector was designed for the nominal instantaneous LHC luminosity of 1 x 1034 cm-2s-1 . The LHC has already started to exceed this luminosity causing the CMS pixel detector to see a dynamic inefficiency caused by data losses due to buffer overflows. For this reason the CMS Collaboration has been building an upgraded pixel detector which is scheduled for installation during an extended year end technical stop during winter 2016/2017. The phase 1 upgrade includes four barrel layers and three forward disks, providing robust tracking and vertexing for LHC luminosities up to 2 x 1034 cm-2s-1 . The upgrade incorporates new readout chips, front-end electronics, DC-DC powering, and dual-phase CO2 cooling to achieve performance exceeding that of the present detector with a lower material budget. This contribution will review the design and technology choices of the Phase I detector and discuss the status of the detector. The challenges and difficulties encountered during the construction will also be presented, as well as the lessons learned for future upgrades. National Science Foundation.

  4. Sub pixel location identification using super resolved multilooking CHRIS data

    NASA Astrophysics Data System (ADS)

    Sahithi, V. S.; Agrawal, S.

    2014-11-01

    CHRIS /Proba is a multiviewing hyperspectral sensor that monitors the earth in five different zenith angles +55°, +36°, nadir, -36° and -55° with a spatial resolution of 17 m and within a spectral range of 400-1050 nm in mode 3. These multiviewing images are suitable for constructing a super resolved high resolution image that can reveal the mixed pixel of the hyperspectral image. In the present work, an attempt is made to find the location of various features constituted within the 17m mixed pixel of the CHRIS image using various super resolution reconstruction techniques. Four different super resolution reconstruction techniques namely interpolation, iterative back projection, projection on to convex sets (POCS) and robust super resolution were tried on the -36, nadir and +36 images to construct a super resolved high resolution 5.6 m image. The results of super resolution reconstruction were compared with the scaled nadir image and bicubic convoluted image for comparision of the spatial and spectral property preservance. A support vector machine classification of the best super resolved high resolution image was performed to analyse the location of the sub pixel features. Validation of the obtained results was performed using the spectral unmixing fraction images and the 5.6 m classified LISS IV image.

  5. Testbeam and laboratory characterization of 3D CMS pixel sensors

    NASA Astrophysics Data System (ADS)

    Bubna, Mayur; Krzwyda, Alex; Alagoz, Enver; Bortoletto, Daniela

    2013-04-01

    Future generations of colliders, like High Luminosity Large Hadron Collider (HL-LHC) at CERN will deliver much higher radiation doses to the particle detectors, specifically those closer to the beam line. Inner tracker detectors will be the most affected part, causing increased occupancy and radiation damage to Silicon detectors. Planar Silicon sensors have not shown enough radiation hardness for the innermost layers where the radiation doses can reach values around 10^16 neq/cm^2. As a possible replacement of planar pixel sensors, 3D Silicon technology is under consideration as they show higher radiation hardness, and efficiencies comparable to planar sensors. Several 3D CMS pixel designs were fabricated at FBK, CNM, and SINTEF. They were bump bonded to the CMS pixel readout chip and characterized in the laboratory using radioactive source (Sr90), and at Fermilab MTEST beam test facility. Sensors were also irradiated with 800 MeV protons at Los Alamos National Lab to study post-irradiation behavior. In addition, several diodes and test structures from FBK were studied before and after irradiation. We report the laboratory and testbeam measurement results for the irradiated 3D devices.

  6. Demosaiced pixel super-resolution for multiplexed holographic color imaging

    NASA Astrophysics Data System (ADS)

    Wu, Yichen; Zhang, Yibo; Luo, Wei; Ozcan, Aydogan

    2016-06-01

    To synthesize a holographic color image, one can sequentially take three holograms at different wavelengths, e.g., at red (R), green (G) and blue (B) parts of the spectrum, and digitally merge them. To speed up the imaging process by a factor of three, a Bayer color sensor-chip can also be used to demultiplex three wavelengths that simultaneously illuminate the sample and digitally retrieve individual set of holograms using the known transmission spectra of the Bayer color filters. However, because the pixels of different channels (R, G, B) on a Bayer color sensor are not at the same physical location, conventional demosaicing techniques generate color artifacts in holographic imaging using simultaneous multi-wavelength illumination. Here we demonstrate that pixel super-resolution can be merged into the color de-multiplexing process to significantly suppress the artifacts in wavelength-multiplexed holographic color imaging. This new approach, termed Demosaiced Pixel Super-Resolution (D-PSR), generates color images that are similar in performance to sequential illumination at three wavelengths, and therefore improves the speed of holographic color imaging by 3-fold. D-PSR method is broadly applicable to holographic microscopy applications, where high-resolution imaging and multi-wavelength illumination are desired.

  7. First results from electrical qualification measurements on DEPFET pixel detector

    NASA Astrophysics Data System (ADS)

    Majewski, Petra; Andricek, Ladislav; Lauf, Thomas; Lechner, Peter; Lutz, Gerhard; Reiffers, Jonas; Richter, Rainer; Schaller, Gerhard; Schnecke, Martina; Schopper, Florian; Soltau, Heike; Stefanescu, Alexander; Strüder, Lothar; Treis, Johannes

    2010-07-01

    We report on the first results from a new setup for electrical qualification measurements of DEPFET pixel detector matrices. In order to measure the transistor properties of all pixels, the DEPFET device is placed into a benchtest setup and electrically contacted via a probecard. Using a switch matrix, each pixel of the detector array can be addressed individually for characterization. These measurements facilitate to pre-select the best DEPFET matrices as detector device prior to the mounting of the matrix and allow to investigate topics like the homogeneity of transistor parameters on device, wafer and batch level in order to learn about the stability and reproducibility of the production process. Especially with regard to the detector development for the IXO Wide Field Imager (WFI), this yield learning will be an important tool. The first electrical qualification measurements with this setup were done on DEPFET macropixel detector flight hardware, which will form the FPAs of the Mercury Imaging X-ray Spectrometer (MIXS) on board of the 5th ESA cornerstone mission BepiColombo. The DEPFET array consists of 64×64 macropixel for which the transfer, output and clear characteristics were measured.

  8. Demosaiced pixel super-resolution for multiplexed holographic color imaging

    PubMed Central

    Wu, Yichen; Zhang, Yibo; Luo, Wei; Ozcan, Aydogan

    2016-01-01

    To synthesize a holographic color image, one can sequentially take three holograms at different wavelengths, e.g., at red (R), green (G) and blue (B) parts of the spectrum, and digitally merge them. To speed up the imaging process by a factor of three, a Bayer color sensor-chip can also be used to demultiplex three wavelengths that simultaneously illuminate the sample and digitally retrieve individual set of holograms using the known transmission spectra of the Bayer color filters. However, because the pixels of different channels (R, G, B) on a Bayer color sensor are not at the same physical location, conventional demosaicing techniques generate color artifacts in holographic imaging using simultaneous multi-wavelength illumination. Here we demonstrate that pixel super-resolution can be merged into the color de-multiplexing process to significantly suppress the artifacts in wavelength-multiplexed holographic color imaging. This new approach, termed Demosaiced Pixel Super-Resolution (D-PSR), generates color images that are similar in performance to sequential illumination at three wavelengths, and therefore improves the speed of holographic color imaging by 3-fold. D-PSR method is broadly applicable to holographic microscopy applications, where high-resolution imaging and multi-wavelength illumination are desired. PMID:27353242

  9. ATLAS pixel detector design for the HL-LHC

    NASA Astrophysics Data System (ADS)

    Smart, B.

    2017-02-01

    The ATLAS Inner Detector will be replaced for the High-Luminosity LHC (HL-LHC) running in 2026. The new Inner Detector is called the Inner Tracker (ITk). The ITk will cover an extended η-range: at least to |η|<3.2, and likely up to 0|η|<4.. The ITk will be an all-Silicon based detector, consisting of a Silicon strip detector outside of a radius of 362 mm, and a Silicon pixel detector inside of this radius. Several novel designs are being considered for the ITk pixel detector, to cope with high-eta charged particle tracks. These designs are grouped into `extended' and `inclined' design-types. Extended designs have long pixel staves with sensors parallel to the beamline, while inclined designs have sensors angled such that they point towards the interaction point. The relative advantages and challenges of these two classes of designs will be examined in this paper, along with the mechanical solutions being considered. Thermal management, radiation-length mapping, and electrical services will also be discussed.

  10. A beam monitor using silicon pixel sensors for hadron therapy

    NASA Astrophysics Data System (ADS)

    Wang, Zhen; Zou, Shuguang; Fan, Yan; Liu, Jun; Sun, Xiangming; Wang, Dong; Kang, Huili; Sun, Daming; Yang, Ping; Pei, Hua; Huang, Guangming; Xu, Nu; Gao, Chaosong; Xiao, Le

    2017-03-01

    We report the design and test results of a beam monitor developed for online monitoring in hadron therapy. The beam monitor uses eight silicon pixel sensors, Topmetal-II-, as the anode array. Topmetal-II- is a charge sensor designed in a CMOS 0.35 μm technology. Each Topmetal-II- sensor has 72×72 pixels and the pixel size is 83×83 μm2. In our design, the beam passes through the beam monitor without hitting the electrodes, making the beam monitor especially suitable for monitoring heavy ion beams. This design also reduces radiation damage to the beam monitor itself. The beam monitor is tested with a carbon ion beam at the Heavy Ion Research Facility in Lanzhou (HIRFL). Results indicate that the beam monitor can measure position, incidence angle and intensity of the beam with a position resolution better than 20 μm, angular resolution about 0.5° and intensity statistical accuracy better than 2%.

  11. Simulation of charge transport in pixelated CdTe

    NASA Astrophysics Data System (ADS)

    Kolstein, M.; Ariño, G.; Chmeissani, M.; De Lorenzo, G.

    2014-12-01

    The Voxel Imaging PET (VIP) Pathfinder project intends to show the advantages of using pixelated semiconductor technology for nuclear medicine applications to achieve an improved image reconstruction without efficiency loss. It proposes designs for Positron Emission Tomography (PET), Positron Emission Mammography (PEM) and Compton gamma camera detectors with a large number of signal channels (of the order of 106). The design is based on the use of a pixelated CdTe Schottky detector to have optimal energy and spatial resolution. An individual read-out channel is dedicated for each detector voxel of size 1 × 1 × 2 mm3 using an application-specific integrated circuit (ASIC) which the VIP project has designed, developed and is currently evaluating experimentally. The behaviour of the signal charge carriers in CdTe should be well understood because it has an impact on the performance of the readout channels. For this purpose the Finite Element Method (FEM) Multiphysics COMSOL software package has been used to simulate the behaviour of signal charge carriers in CdTe and extract values for the expected charge sharing depending on the impact point and bias voltage. The results on charge sharing obtained with COMSOL are combined with GAMOS, a Geant based particle tracking Monte Carlo software package, to get a full evaluation of the amount of charge sharing in pixelated CdTe for different gamma impact points.

  12. Simulation of charge transport in pixelated CdTe

    PubMed Central

    Kolstein, M.; Ariño, G.; Chmeissani, M.; De Lorenzo, G.

    2014-01-01

    The Voxel Imaging PET (VIP) Pathfinder project intends to show the advantages of using pixelated semiconductor technology for nuclear medicine applications to achieve an improved image reconstruction without efficiency loss. It proposes designs for Positron Emission Tomography (PET), Positron Emission Mammography (PEM) and Compton gamma camera detectors with a large number of signal channels (of the order of 106). The design is based on the use of a pixelated CdTe Schottky detector to have optimal energy and spatial resolution. An individual read-out channel is dedicated for each detector voxel of size 1 × 1 × 2 mm3 using an application-specific integrated circuit (ASIC) which the VIP project has designed, developed and is currently evaluating experimentally. The behaviour of the signal charge carriers in CdTe should be well understood because it has an impact on the performance of the readout channels. For this purpose the Finite Element Method (FEM) Multiphysics COMSOL software package has been used to simulate the behaviour of signal charge carriers in CdTe and extract values for the expected charge sharing depending on the impact point and bias voltage. The results on charge sharing obtained with COMSOL are combined with GAMOS, a Geant based particle tracking Monte Carlo software package, to get a full evaluation of the amount of charge sharing in pixelated CdTe for different gamma impact points. PMID:25729404

  13. Spectroscopic and imaging capabilities of a pixellated photon counting system

    NASA Astrophysics Data System (ADS)

    Amendolia, S. R.; Bisogni, M. G.; Bottigli, U.; Delogu, P.; Dipasquale, G.; Fantacci, M. E.; Marchi, A.; Marzulli, V. M.; Oliva, P.; Palmiero, R.; Rosso, V.; Stefanini, A.; Stumbo, S.; Zucca, S.

    2001-06-01

    We are studying the performance of various thickness GaAs pixel detectors bump-bonded to a dedicated photon counting chip (PCC) for medical imaging applications in different energy ranges. In this work we present the experimental results obtained with a 600 μm thick pixel matrix (64×64 square pixels, 170 μm side) in the 60-140 keV energy range to evaluate the possible use of such a system in the nuclear medicine field. In particular, we have measured the spectroscopic properties of the detector (charge collection efficiency, energy resolution and detection efficiency) and evaluated the discrimination capability of the electronics. Then we have measured the imaging properties of the whole system in terms of Point Spread Function and using a home made thyroid phantom. We present also a comparison with a traditional gamma camera and an evaluation, made by both experimental measurements and software simulations, of the imaging characteristics related to the use of a collimation system.

  14. Simulation of charge transport in pixelated CdTe.

    PubMed

    Kolstein, M; Ariño, G; Chmeissani, M; De Lorenzo, G

    2014-12-01

    The Voxel Imaging PET (VIP) Pathfinder project intends to show the advantages of using pixelated semiconductor technology for nuclear medicine applications to achieve an improved image reconstruction without efficiency loss. It proposes designs for Positron Emission Tomography (PET), Positron Emission Mammography (PEM) and Compton gamma camera detectors with a large number of signal channels (of the order of 10(6)). The design is based on the use of a pixelated CdTe Schottky detector to have optimal energy and spatial resolution. An individual read-out channel is dedicated for each detector voxel of size 1 × 1 × 2 mm(3) using an application-specific integrated circuit (ASIC) which the VIP project has designed, developed and is currently evaluating experimentally. The behaviour of the signal charge carriers in CdTe should be well understood because it has an impact on the performance of the readout channels. For this purpose the Finite Element Method (FEM) Multiphysics COMSOL software package has been used to simulate the behaviour of signal charge carriers in CdTe and extract values for the expected charge sharing depending on the impact point and bias voltage. The results on charge sharing obtained with COMSOL are combined with GAMOS, a Geant based particle tracking Monte Carlo software package, to get a full evaluation of the amount of charge sharing in pixelated CdTe for different gamma impact points.

  15. Spatial Pileup Considerations for Pixellated Gamma -ray Detectors

    PubMed Central

    Furenlid, L.R.; Clarkson, E.; Marks, D.G.; Barrett, H.H.

    2015-01-01

    High-spatial-resolution solid-state detectors being developed for gamma-ray applications benefit from having pixel dimensions substantially smaller than detector slab thickness. This leads to an enhanced possibility of charge partially spreading to neighboring pixels as a result of diffusion (and secondary photon emission) transverse to the drift direction. An undesirable consequence is the effective magnification of the event “size“ and the spatial overlap issues which result when two photons are absorbed in close proximity within the integration time of the detector/readout system. In this work, we develop the general statistics of spatial pileup in imaging systems and apply the results to detectors we are developing based on pixellated cadmium zinc telluride (CdZnTe) and a multiplexing application-specific integrated circuit (ASIC) readout. We consider the limitations imposed on total count rate capacity and explore in detail the consequences for the LISTMODE data-acquisition strategy. Algorithms are proposed for identifying and, where possible, resolving overlapping events by maximum-likelihood estimation. The efficacy and noise tolerance of these algorithms will be tested with a combination of simulated and experimental data in future work. PMID:26568675

  16. [Study on the reflected and hyperspectral mixed-pixel character of aquatic plants and water].

    PubMed

    Sun, Tian-lin; Zhao, Yun-sheng; Liang, Ren-feng; Zhang, Xia

    2012-02-01

    A study on the reflected and hyperspectral mixed-pixel of aquatic plants and water was given by using a orthogonal experimental design with three factors and two levels. The results of F test suggest that for the single factors, the band and the area ratio of mixed-pixel on the reflected and hyperspectral mixed-pixel of the reflection effects are particularly significant, however, the detector angle had no significant effect under these experimental conditions; For the interaction, the band and the area ratio of mixed-pixel, the detector and the area ratio of mixed-pixel, the effects of these two interactions on the reflected and hyperspectral mixed-pixel are also particularly significant, This study did quantitative analysis of the factors affecting the reflected and hyperspectral mixed-pixel character and their interaction, and provided a new method for the indepth study of mixed-pixel.

  17. Hexagonal Pixels and Indexing Scheme for Binary Images

    NASA Technical Reports Server (NTRS)

    Johnson, Gordon G.

    2004-01-01

    A scheme for resampling binaryimage data from a rectangular grid to a regular hexagonal grid and an associated tree-structured pixel-indexing scheme keyed to the level of resolution have been devised. This scheme could be utilized in conjunction with appropriate image-data-processing algorithms to enable automated retrieval and/or recognition of images. For some purposes, this scheme is superior to a prior scheme that relies on rectangular pixels: one example of such a purpose is recognition of fingerprints, which can be approximated more closely by use of line segments along hexagonal axes than by line segments along rectangular axes. This scheme could also be combined with algorithms for query-image-based retrieval of images via the Internet. A binary image on a rectangular grid is generated by raster scanning or by sampling on a stationary grid of rectangular pixels. In either case, each pixel (each cell in the rectangular grid) is denoted as either bright or dark, depending on whether the light level in the pixel is above or below a prescribed threshold. The binary data on such an image are stored in a matrix form that lends itself readily to searches of line segments aligned with either or both of the perpendicular coordinate axes. The first step in resampling onto a regular hexagonal grid is to make the resolution of the hexagonal grid fine enough to capture all the binaryimage detail from the rectangular grid. In practice, this amounts to choosing a hexagonal-cell width equal to or less than a third of the rectangular- cell width. Once the data have been resampled onto the hexagonal grid, the image can readily be checked for line segments aligned with the hexagonal coordinate axes, which typically lie at angles of 30deg, 90deg, and 150deg with respect to say, the horizontal rectangular coordinate axis. Optionally, one can then rotate the rectangular image by 90deg, then again sample onto the hexagonal grid and check for line segments at angles of 0deg, 60deg

  18. Restoring the ON Switch in Blind Retinas: Opto-mGluR6, a Next-Generation, Cell-Tailored Optogenetic Tool

    PubMed Central

    van Wyk, Michiel; Pielecka-Fortuna, Justyna; Löwel, Siegrid; Kleinlogel, Sonja

    2015-01-01

    Photoreceptor degeneration is one of the most prevalent causes of blindness. Despite photoreceptor loss, the inner retina and central visual pathways remain intact over an extended time period, which has led to creative optogenetic approaches to restore light sensitivity in the surviving inner retina. The major drawbacks of all optogenetic tools recently developed and tested in mouse models are their low light sensitivity and lack of physiological compatibility. Here we introduce a next-generation optogenetic tool, Opto-mGluR6, designed for retinal ON-bipolar cells, which overcomes these limitations. We show that Opto-mGluR6, a chimeric protein consisting of the intracellular domains of the ON-bipolar cell–specific metabotropic glutamate receptor mGluR6 and the light-sensing domains of melanopsin, reliably recovers vision at the retinal, cortical, and behavioral levels under moderate daylight illumination. PMID:25950461

  19. OptoGluNAM4.1, a Photoswitchable Allosteric Antagonist for Real-Time Control of mGlu4 Receptor Activity.

    PubMed

    Rovira, Xavier; Trapero, Ana; Pittolo, Silvia; Zussy, Charleine; Faucherre, Adèle; Jopling, Chris; Giraldo, Jesús; Pin, Jean-Philippe; Gorostiza, Pau; Goudet, Cyril; Llebaria, Amadeu

    2016-08-18

    OptoGluNAM4.1, a negative allosteric modulator (NAM) of metabotropic glutamate receptor 4 (mGlu4) contains a reactive group that covalently binds to the receptor and a blue-light-activated, fast-relaxing azobenzene group that allows reversible receptor activity photocontrol in vitro and in vivo. OptoGluNAM4.1 induces light-dependent behavior in zebrafish and reverses the activity of the mGlu4 agonist LSP4-2022 in a mice model of chronic pain, defining a photopharmacological tool to better elucidate the physiological roles of the mGlu4 receptor in the nervous system.

  20. Method of fabrication of display pixels driven by silicon thin film transistors

    DOEpatents

    Carey, Paul G.; Smith, Patrick M.

    1999-01-01

    Display pixels driven by silicon thin film transistors are fabricated on plastic substrates for use in active matrix displays, such as flat panel displays. The process for forming the pixels involves a prior method for forming individual silicon thin film transistors on low-temperature plastic substrates. Low-temperature substrates are generally considered as being incapable of withstanding sustained processing temperatures greater than about 200.degree. C. The pixel formation process results in a complete pixel and active matrix pixel array. A pixel (or picture element) in an active matrix display consists of a silicon thin film transistor (TFT) and a large electrode, which may control a liquid crystal light valve, an emissive material (such as a light emitting diode or LED), or some other light emitting or attenuating material. The pixels can be connected in arrays wherein rows of pixels contain common gate electrodes and columns of pixels contain common drain electrodes. The source electrode of each pixel TFT is connected to its pixel electrode, and is electrically isolated from every other circuit element in the pixel array.

  1. Development of a super B-factory monolithic active pixel detector—the Continuous Acquisition Pixel (CAP) prototypes

    NASA Astrophysics Data System (ADS)

    Varner, G.; Barbero, M.; Bozek, A.; Browder, T.; Fang, F.; Hazumi, M.; Igarashi, A.; Iwaida, S.; Kennedy, J.; Kent, N.; Olsen, S.; Palka, H.; Rosen, M.; Ruckman, L.; Stanic, S.; Trabelsi, K.; Tsuboyama, T.; Uchida, K.

    2005-04-01

    Over the last few years great progress has been made in the technological development of Monolithic Active Pixel Sensors (MAPS) such that upgrades to existing vertex detectors using this technology are now actively being considered. Future vertex detection at an upgraded KEK-B factory, already the highest luminosity collider in the world, will require a detector technology capable of withstanding the increased track densities and larger radiation exposures. Near the beam pipe the current silicon strip detectors have projected occupancies in excess of 100%. Deep sub-micron MAPS look very promising to address this problem. In the context of an upgrade to the Belle vertex detector, the major obstacles to realizing such a device have been concerns about radiation hardness and readout speed. Two prototypes implemented in the TSMC 0.35 μm process have been developed to address these issues. Denoted the Continuous Acquisition Pixel, or CAP, the two variants of this architecture are distinguished in that CAP2 includes an 8-deep sampling pipeline within each 22.5 μm 2 pixel. Preliminary test results and remaining R&D issues are presented.

  2. Transatlantic link

    NASA Astrophysics Data System (ADS)

    (left) European Geophysical Society (EGS) President Rolf Meissner at AGU Headquarters with (center) Executive Director Fred Spilhaus and (right) Foreign Secretary Juan Roederer. Meissner attended the meeting of AGU's Committee on International Participation (CIP) on February 26, 1988. At that meeting, specific ways of fostering close links between AGU and EGS were discussed.A few weeks later, Roederer and AGU staff, working with EGS Secretary-General Arne Richter at the EGS meeting in Bologna, Italy, March 21-25, planned details of the establishment of an AGU office in Europe. The Copernicus Gesellschaft, a new entity located on the premises of the Max Planck Institute for Aeronomy in Lindau, Federal Republic of Germany, will provide the administrative staff and handle logistics.

  3. Facile synthesis of carbon doped TiO2 nanowires without an external carbon source and their opto-electronic properties.

    PubMed

    Kiran, Vankayala; Sampath, Srinivasan

    2013-11-07

    The present study demonstrates a simple protocol for the preparation of one dimensional (1D) oxidized titanium carbide nanowires and their opto-electronic properties. The oxidized titanium carbide nanowires (Ox-TiC-NW) are prepared from TiC nanowires (TiC-NW) that are in turn synthesized from micron sized TiC particles using the solvothermal technique. The Ox-TiC-NW is characterized by X-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Raman spectroscopy. Thermal oxidation of TiC-NW yields carbon doped TiO2-NW (C-TiO2-NW), a simple methodology to obtain 1D C-TiO2-NW. Temperature dependent Raman spectra reveal characteristic bands for TiO2-NW. Electrical characterization of individual C-TiO2-NW is performed by fabricating a device structure using the focused ion beam deposition technique. The opto-electronic properties of individual C-TiO2-NW demonstrate visible light activity and the parameters obtained from photoconductivity measurements reveal very good sensitivity. This methodology opens up the possibility of using C-TiO2-NW in electronic and opto-electronic device applications.

  4. Sub-pixel calibration for Weak Lensing and Astrometry

    NASA Astrophysics Data System (ADS)

    Shao, Michael

    We have recently developed and demonstrated a new method of sub-pixel detector calibration that offers orders of magnitude improvement in astrometry with CCD focal planes. Using this technique we have demonstrated centroiding of images to 1e 5 lambda/D in laboratory conditions. Our method allows reconstructing the true optical point spread function (PSF) of a telescope from pixelated stellar images. Although this technique was originally developed for centroiding of images across a large focal plane, it can also be applied to weak lensing program on WFIRST. We use a laser metrology technique to measure geometric imperfections in the focal plane array from pixel placement errors to non-uniform quantum efficiency (QE) within every pixel. With precise sub-pixel calibration one can use dithered images (e.g., a 2×2 dither) to derive Nyquist-sampled image of stars. The WFIRST telescope has a large 0.28 sq.deg field of view (FOV) with theoretical PSF varying considerably over that FOV. However, even at high galactic latitude there will be over 1,000 stars brighter than 16 mag and, with Nyquist-sampled images, it should be possible to calculate the spatially varying PSF at 1,000 locations in the focal plane. With knowledge of the optical PSF and sub-pixel calibration of the detector, one can remove biases in the shapes of galaxies introduced by the spatially varying PSF. The technique of sub-pixel calibration has so far only been demonstrated in with visible CCD detectors and applied to achieve ultra-precise image centroiding. The purpose of this proposal is to extend the technique of removing biases in the shape of galaxies due to pixilation and spatially varying PSF and to extend the calibration of visible detectors to NIR detectors. The new technique could be used to enable 4 10 microarcsecond (μas) astrometry within the 0.28 sq.deg FOV of the WFIRST telescope. Using the upcoming Gaia catalogue accurate to ~10 μas, we will be able to stitch the HgCdTe arrays on

  5. Optical differentiation wavefront sensor based on binary pixelated transmission filters

    NASA Astrophysics Data System (ADS)

    Qiao, J.; Travinsky, A.; Ding, G.; Dorrer, C.

    2015-03-01

    High-resolution wavefront sensors are used in a wide range of applications. The Shack-Hartmann sensor is the industry standard and mostly used for this kind of analysis. However, with this sensor the analysis can only be performed for narrowband radiation, the recoverable curvature of the wavefront slopes is also restricted by the size of a single lens in the microlens array. The high-resolution Shack Hartmann wavefront sensor (>128×128) is also significantly expensive. The optical differentiation wavefront sensor, on the other hand, consists of only simple and therefore inexpensive components, offers greater signal to noise ratio, allows for high-resolution analysis of wavefront curvature, and is potentially capable of performing broadband measurements. When a transmission mask with linear attenuation along a spatial direction modulates the far field of an optical wave, the spatial wavefront slope along that direction can be recovered from the fluence in the near field after modulation. With two orthogonal measurements one can recover the complete wavefront of the optical wave. In this study the characteristics of such a wavefront sensor are investigated when the linear transmission modulation is implemented with a pixelated binary filter. Such a filter can be produced as a gray-scale quasi-continuous transmission pattern constructed using arrays of small (e.g., 10-micron) transparent or opaque pixels and therefore it can simply be fabricated by conventional lithography techniques. Simulations demonstrate the potential ability of such a pixelated filter to match the performance of a filter with continuously varying transmission, while offering the advantage of better transmission control and reduction of fabrication costs.

  6. CMOS Hybrid Pixel Detectors for Scientific, Industrial and Medical Applications

    NASA Astrophysics Data System (ADS)

    Broennimann, Christian

    2009-03-01

    Crystallography is the principal technique for determining macromolecular structures at atomic resolution and uses advantageously the high intensity of 3rd generation synchrotron X-ray sources . Macromolecular crystallography experiments benefit from excellent beamline equipment, recent software advances and modern X-ray detectors. However, the latter do not take full advantage of the brightness of modern synchrotron sources. CMOS Hybrid pixel array detectors, originally developed for high energy physics experiments, meet these requirements. X-rays are recorded in single photon counting mode and data thus are stored digitally at the earliest possible stage. This architecture leads to several advantages over current detectors: No detector noise is added to the signal. Readout time is reduced to a few milliseconds. The counting rates are matched to beam intensities at protein crystallography beamlines at 3rd generation synchrotrons. The detector is not sensitive to X-rays during readout; therefore no mechanical shutter is required. The detector has a very sharp point spread function (PSF) of one pixel, which allows better resolution of adjacent reflections. Low energy X-rays can be suppressed by the comparator At the Paul Scherrer Institute (PSI) in Switzerland the first and largest array based on this technology was constructed: The Pilatus 6M detector. The detector covers an area of 43.1 x 44.8 cm2 , has 6 million pixels and is read out noise free in 3.7 ms. Since June 2007 the detector is in routine operation at the beamline 6S of the Swiss Light Source (SLS). The company DETCRIS Ltd, has licensed the technology from PSI and is commercially offering the PILATUS detectors. Examples of the wide application range of the detectors will be shown.

  7. Study of silicon pixel sensor for synchrotron radiation detection

    NASA Astrophysics Data System (ADS)

    Li, Zhen-Jie; Jia, Yun-Cong; Hu, Ling-Fei; Liu, Peng; Yin, Hua-Xiang

    2016-03-01

    The silicon pixel sensor (SPS) is one of the key components of hybrid pixel single-photon-counting detectors for synchrotron radiation X-ray detection (SRD). In this paper, the design, fabrication, and characterization of SPSs for single beam X-ray photon detection is reported. The designed pixel sensor is a p+-in-n structure with guard-ring structures operated in full-depletion mode and is fabricated on 4-inch, N type, 320 μm thick, high-resistivity silicon wafers by a general Si planar process. To achieve high energy resolution of X-rays and obtain low dark current and high breakdown voltage as well as appropriate depletion voltage of the SPS, a series of technical optimizations of device structure and fabrication process are explored. With optimized device structure and fabrication process, excellent SPS characteristics with dark current of 2 nA/cm2, full depletion voltage < 50 V and breakdown voltage >150 V are achieved. The fabricated SPSs are wire bonded to ASIC circuits and tested for the performance of X-ray response to the 1W2B synchrotron beam line of the Beijing Synchrotron Radiation Facility. The measured S-curves for SRD demonstrate a high discrimination for different energy X-rays. The extracted energy resolution is high (<20% for X-ray photon energy >10 keV) and the linear properties between input photo energy and the equivalent generator amplitude are well established. It confirmed that the fabricated SPSs have a good energy linearity and high count rate with the optimized technologies. The technology is expected to have a promising application in the development of a large scale SRD system for the Beijing Advanced Photon Source. Supported by Prefabrication Research of Beijing Advanced Photon Source (R&D for BAPS) and National Natural Science Foundation of China (11335010)

  8. A metamaterial-based single pixel imaging system (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Padilla, Willie J.

    2016-09-01

    Electromagnetic metamaterials have demonstrated unprecedented control over light matter interactions and have realized exotic responses difficult to achieve with natural materials. The ability to achieve real-time control of novel responses exhibited by electromagnetic metamaterials has led to the realization of metadevices and metasystems. Here we experimentally demonstrate two realizations of single pixel imaging systems that rely entirely on all-electronic metamaterial spatial light modulators. The metasystem enables images to be digitally encoded with various measurement matrix coefficients, thus permitting high speed and fidelity imaging.

  9. Position-Sensitive Nuclear Spectroscopy with Pixel Detectors

    SciTech Connect

    Granja, Carlos; Vykydal, Zdenek; Jakubek, Jan; Pospisil, Stanislav

    2007-10-26

    State-of-the-art hybrid semiconductor pixel detectors such as Medipix2 are suitable for energy- and position-sensitive nuclear spectroscopy. In addition to excellent energy- and spatial-resolution, these devices can operate in spectroscopic, single-quantum counting and/or on-line tracking mode. A devoted compact USB-readout interface provides functionality and ease of operation. The compact and versatile Medipix2/USB radiation camera provides visualization, vacuum and room-temperature operation as a real-time portable active nuclear emulsion.

  10. Dissolve Detection Using Intensity Change Information of Edge Pixels

    NASA Astrophysics Data System (ADS)

    Kwon, Chul-Hyun; Han, Doo-Jin; Kim, Hyun-Sool; Lee, Myung-Ho; Park, Sang-Hui

    Shot transition detection is a core technology in video browsing, indexing systems and information retrieval. In this paper we propose a dissolve detection algorithm using the characteristics of edge in MPEG compressed video. Using the intensity change information of edge pixels obtained by Sobel edge detector, we detect the location of a dissolve and its precise duration. We also present a new reliable method to eliminate the false dissolves. The proposed algorithm is tested in various types of videos, and the experimental results show that the proposed algorithm is effective and robust.

  11. Pixel DAQ and trigger for HL-LHC

    NASA Astrophysics Data System (ADS)

    Morettini, P.

    2017-03-01

    The read-out is one of the challenges in the design of a pixel detector for the High Luminosity upgrade of the Large Hadron Collider (HL-LHC), that is expected to operate from 2026 at a leveled luminosity of 5 × 1034 cm‑2 s‑1. This is especially true if tracking information is needed in a low latency trigger system. The difficulties of a fast read-out will be reviewed, and possible strategies explained. The solutions that are being evaluated by the ATLAS and CMS collaborations for the upgrade of their trackers will be outlined and ideas on possible development beyond HL-LHC will be presented.

  12. Hyperspectral imaging using the single-pixel Fourier transform technique

    NASA Astrophysics Data System (ADS)

    Jin, Senlin; Hui, Wangwei; Wang, Yunlong; Huang, Kaicheng; Shi, Qiushuai; Ying, Cuifeng; Liu, Dongqi; Ye, Qing; Zhou, Wenyuan; Tian, Jianguo

    2017-03-01

    Hyperspectral imaging technology is playing an increasingly important role in the fields of food analysis, medicine and biotechnology. To improve the speed of operation and increase the light throughput in a compact equipment structure, a Fourier transform hyperspectral imaging system based on a single-pixel technique is proposed in this study. Compared with current imaging spectrometry approaches, the proposed system has a wider spectral range (400–1100 nm), a better spectral resolution (1 nm) and requires fewer measurement data (a sample rate of 6.25%). The performance of this system was verified by its application to the non-destructive testing of potatoes.

  13. Hyperspectral imaging using the single-pixel Fourier transform technique

    PubMed Central

    Jin, Senlin; Hui, Wangwei; Wang, Yunlong; Huang, Kaicheng; Shi, Qiushuai; Ying, Cuifeng; Liu, Dongqi; Ye, Qing; Zhou, Wenyuan; Tian, Jianguo

    2017-01-01

    Hyperspectral imaging technology is playing an increasingly important role in the fields of food analysis, medicine and biotechnology. To improve the speed of operation and increase the light throughput in a compact equipment structure, a Fourier transform hyperspectral imaging system based on a single-pixel technique is proposed in this study. Compared with current imaging spectrometry approaches, the proposed system has a wider spectral range (400–1100 nm), a better spectral resolution (1 nm) and requires fewer measurement data (a sample rate of 6.25%). The performance of this system was verified by its application to the non-destructive testing of potatoes. PMID:28338100

  14. Independent pixel and Monte Carlo estimates of stratocumulus albedo

    NASA Technical Reports Server (NTRS)

    Cahalan, Robert F.; Ridgway, William; Wiscombe, Warren J.; Gollmer, Steven; HARSHVARDHAN

    1994-01-01

    Monte Carlo radiative transfer methods are employed here to estimate the plane-parallel albedo bias for marine stratocumulus clouds. This is the bias in estimates of the mesoscale-average albedo, which arises from the assumption that cloud liquid water is uniformly distributed. The authors compare such estimates with those based on a more realistic distribution generated from a fractal model of marine stratocumulus clouds belonging to the class of 'bounded cascade' models. In this model the cloud top and base are fixed, so that all variations in cloud shape are ignored. The model generates random variations in liquid water along a single horizontal direction, forming fractal cloud streets while conserving the total liquid water in the cloud field. The model reproduces the mean, variance, and skewness of the vertically integrated cloud liquid water, as well as its observed wavenumber spectrum, which is approximately a power law. The Monte Carlo method keeps track of the three-dimensional paths solar photons take through the cloud field, using a vectorized implementation of a direct technique. The simplifications in the cloud field studied here allow the computations to be accelerated. The Monte Carlo results are compared to those of the independent pixel approximation, which neglects net horizontal photon transport. Differences between the Monte Carlo and independent pixel estimates of the mesoscale-average albedo are on the order of 1% for conservative scattering, while the plane-parallel bias itself is an order of magnitude larger. As cloud absorption increases, the independent pixel approximation agrees even more closely with the Monte Carlo estimates. This result holds for a wide range of sun angles and aspect ratios. Thus, horizontal photon transport can be safely neglected in estimates of the area-average flux for such cloud models. This result relies on the rapid falloff of the wavenumber spectrum of stratocumulus, which ensures that the smaller

  15. Thin hybrid pixel assembly with backside compensation layer on ROIC

    NASA Astrophysics Data System (ADS)

    Bates, R.; Buttar, C.; McMullen, T.; Cunningham, L.; Ashby, J.; Doherty, F.; Gray, C.; Pares, G.; Vignoud, L.; Kholti, B.; Vahanen, S.

    2017-01-01

    The entire ATLAS inner tracking system will be replaced for operation at the HL-LHC . This will include a significantly larger pixel detector of approximately 15 m2. For this project, it is critical to reduce the mass of the hybrid pixel modules and this requires thinning both the sensor and readout chips to about 150 micrometres each. The thinning of the silicon chips leads to low bump yield for SnAg bumps due to bad co-planarity of the two chips at the solder reflow stage creating dead zones within the pixel array. In the case of the ATLAS FEI4 pixel readout chip thinned to 100 micrometres, the chip is concave, with the front side in compression, with a bow of +100 micrometres at room temperature which varies to a bow of -175 micrometres at the SnAg solder reflow temperature, caused by the CTE mismatch between the materials in the CMOS stack and the silicon substrate. A new wafer level process to address the issue of low bump yield be controlling the chip bow has been developed. A back-side dielectric and metal stack of SiN and Al:Si has been deposited on the readout chip wafer to dynamically compensate the stress of the front side stack. In keeping with a 3D process the materials used are compatible with Through Silicon Via (TSV) technology with a TSV last approach which is under development for this chip. It is demonstrated that the amplitude of the correction can be manipulated by the deposition conditions and thickness of the SiN/Al:Si stack. The bow magnitude over the temperature range for the best sample to date is reduced by almost a factor of 4 and the sign of the bow (shape of the die) remains constant. Further development of the backside deposition conditions is on-going with the target of close to zero bow at the solder reflow temperature and a minimal bow magnitude throughout the temperature range. Assemblies produced from FEI4 readout wafers thinned to 100 micrometres with the backside compensation layer have been made for the first time and

  16. An integrating CMOS APS for X-ray imaging with an in-pixel preamplifier

    NASA Astrophysics Data System (ADS)

    Abdalla, M. A.; Fröjdh, C.; Petersson, C. S.

    2001-06-01

    We present in this paper an integrating CMOS Active Pixel Sensor (APS) circuit coated with scintillator type sensors for intra-oral dental X-ray imaging systems. The photosensing element in the pixel is formed by the p-diffusion on the n-well diode. The advantage of this photosensor is its very low direct absorption of X-rays compared to the other available photosensing elements in the CMOS pixel. The pixel features an integrating capacitor in the feedback loop of a preamplifier of a finite gain in order to increase the optical sensitivity. To verify the effectiveness of this in-pixel preamplification, a prototype 32×80 element CMOS active pixel array was implemented in a 0.8 μm CMOS double poly, n-well process with a pixel pitch of 50 μm. Measured results confirmed the improved optical sensitivity performance of the APS. Various measurements on device performance are presented.

  17. A new ATLAS pixel front-end IC for upgraded LHC luminosity

    NASA Astrophysics Data System (ADS)

    Barbero, M.; Arutinov, D.; Beccherle, R.; Darbo, G.; Ely, R.; Fougeron, D.; Garcia-Sciveres, M.; Gnani, D.; Hemperek, T.; Karagounis, M.; Kluit, R.; Kostioukhine, V.; Mekkaoui, A.; Menouni, M.; Schipper, J.-D.

    2009-06-01

    A new pixel Front-End (FE) IC is being developed in a 130 nm technology for use in the upgraded ATLAS pixel detector. The new pixel FE will be made of smaller pixels (50×250 μm vs. 50×400 μm for the present FE, FE-I3), a much improved active area over inactive area ratio, and a new analog pixel chain tuned for low power and new detector input capacitance. The higher luminosity for which this IC is tuned implies a complete redefinition of the digital architecture logic, which will not be based on End-of-Column data buffering but on local pixel logic and local pixel data storage. An overview of the new FE is given with particular emphasis on the new digital logic architecture and possible architecture variations.

  18. A New Pixels Flipping Method for Huge Watermarking Capacity of the Invoice Font Image

    PubMed Central

    Li, Li; Hou, Qingzheng; Lu, Jianfeng; Dai, Junping; Mao, Xiaoyang; Chang, Chin-Chen

    2014-01-01

    Invoice printing just has two-color printing, so invoice font image can be seen as binary image. To embed watermarks into invoice image, the pixels need to be flipped. The more huge the watermark is, the more the pixels need to be flipped. We proposed a new pixels flipping method in invoice image for huge watermarking capacity. The pixels flipping method includes one novel interpolation method for binary image, one flippable pixels evaluation mechanism, and one denoising method based on gravity center and chaos degree. The proposed interpolation method ensures that the invoice image keeps features well after scaling. The flippable pixels evaluation mechanism ensures that the pixels keep better connectivity and smoothness and the pattern has highest structural similarity after flipping. The proposed denoising method makes invoice font image smoother and fiter for human vision. Experiments show that the proposed flipping method not only keeps the invoice font structure well but also improves watermarking capacity. PMID:25489606

  19. Design optimization of pixel sensors using device simulations for the phase-II CMS tracker upgrade

    NASA Astrophysics Data System (ADS)

    Jain, G.; Bhardwaj, A.; Dalal, R.; Eber, R.; Eichorn, T.; Fernandez, M.; Lalwani, K.; Messineo, A.; Palomo, F. R.; Peltola, T.; Printz, M.; Ranjan, K.; Villa, I.; Hidalgo, S.

    2016-07-01

    In order to address the problems caused by the harsh radiation environment during the high luminosity phase of the LHC (HL-LHC), all silicon tracking detectors (pixels and strips) in the CMS experiment will undergo an upgrade. And so to develop radiation hard pixel sensors, simulations have been performed using the 2D TCAD device simulator, SILVACO, to obtain design parameters. The effect of various design parameters like pixel size, pixel depth, implant width, metal overhang, p-stop concentration, p-stop depth and bulk doping density on the leakage current and critical electric field are studied for both non-irradiated as well as irradiated pixel sensors. These 2D simulation results of planar pixels are useful for providing insight into the behaviour of non-irradiated and irradiated silicon pixel sensors and further work on 3D simulation is underway.

  20. The Gauss-Legendre Sky Pixelization for the CMB Polarization Glesp-Pol Errors due to Pixelization of the CMB Sky

    NASA Astrophysics Data System (ADS)

    Doroshkevich, Andrei G.; Verkhodanov, Oleg V.; Naselsky, Pavel D.; Kim, Jaiseung; Novikov, Dmitry I.; Turchaninov, Viktor I.; Novikov, Igor D.; Chiang, Lung-Yih; Hansen, Martin

    We present the development of the method for numerical analysis of polarization in the Gauss-Legendre sky pixelization (GLESP) scheme for CMB maps. This incorporation of the polarization transforms in the pixelization scheme GLESP completes the creation of our new method for numerical analysis of CMB maps. A comparison of GLESP and HEALPix calculations is done.

  1. A multi-channel opto-electronic sensor to accurately monitor heart rate against motion artefact during exercise.

    PubMed

    Alzahrani, Abdullah; Hu, Sijung; Azorin-Peris, Vicente; Barrett, Laura; Esliger, Dale; Hayes, Matthew; Akbare, Shafique; Achart, Jérôme; Kuoch, Sylvain

    2015-10-12

    This study presents the use of a multi-channel opto-electronic sensor (OEPS) to effectively monitor critical physiological parameters whilst preventing motion artefact as increasingly demanded by personal healthcare. The aim of this work was to study how to capture the heart rate (HR) efficiently through a well-constructed OEPS and a 3-axis accelerometer with wireless communication. A protocol was designed to incorporate sitting, standing, walking, running and cycling. The datasets collected from these activities were processed to elaborate sport physiological effects. t-test, Bland-Altman Agreement (BAA), and correlation to evaluate the performance of the OEPS were used against Polar and Mio-Alpha HR monitors. No differences in the HR were found between OEPS, and either Polar or Mio-Alpha (both p > 0.05); a strong correlation was found between Polar and OEPS (r: 0.96, p < 0.001); the bias of BAA 0.85 bpm, the standard deviation (SD) 9.20 bpm, and the limits of agreement (LOA) from -17.18 bpm to +18.88 bpm. For the Mio-Alpha and OEPS, a strong correlation was found (r: 0.96, p < 0.001); the bias of BAA 1.63 bpm, SD 8.62 bpm, LOA from -15.27 bpm to +18.58 bpm. These results demonstrate the OEPS to be capable of carrying out real time and remote monitoring of heart rate.

  2. A theoretical study of a nano-opto-mechanical sensor using a photonic crystal-cantilever cavity

    SciTech Connect

    Mao, Depeng; Liu, Peng; Ho, Kai-Ming; Dong, Liang

    2012-07-09

    In this simulation study, integration of a nanocantilever inside a two-dimensional (2D) photonic crystal (PC) cavity resulted in a unique photonic crystal-cantilever cavity (PC3), where the cantilever served as a tunable mechanical defect of the PC slab. Strong nano-opto-mechanical interactions between the cantilever and the defect-mode field inside the PC3 gave rise to a high sensitivity of the resonance wavelength to surface stress-induced cantilever deflection. Mechanical and optical responses of the PC3 to surface stress changes on the cantilever surface were studied by using a finite-element method (FEM) and a finite-difference time-domain (FDTD) method, respectively. Theoretical analysis revealed that the devised PC3 sensor could resolve a conservative minimum surface stress at the level of ~0.8 mN m−1, representing state-of-the-art cantilever sensor performance. Also, the PC3 sensor design used an ultracompact structure with an on-chip optical length of only several microns, while a conventional reflected laser beam detection scheme requires a ~1 m long free-space optical path.

  3. A Multi-Channel Opto-Electronic Sensor to Accurately Monitor Heart Rate against Motion Artefact during Exercise

    PubMed Central

    Alzahrani, Abdullah; Hu, Sijung; Azorin-Peris, Vicente; Barrett, Laura; Esliger, Dale; Hayes, Matthew; Akbare, Shafique; Achart, Jérôme; Kuoch, Sylvain

    2015-01-01

    This study presents the use of a multi-channel opto-electronic sensor (OEPS) to effectively monitor critical physiological parameters whilst preventing motion artefact as increasingly demanded by personal healthcare. The aim of this work was to study how to capture the heart rate (HR) efficiently through a well-constructed OEPS and a 3-axis accelerometer with wireless communication. A protocol was designed to incorporate sitting, standing, walking, running and cycling. The datasets collected from these activities were processed to elaborate sport physiological effects. t-test, Bland-Altman Agreement (BAA), and correlation to evaluate the performance of the OEPS were used against Polar and Mio-Alpha HR monitors. No differences in the HR were found between OEPS, and either Polar or Mio-Alpha (both p > 0.05); a strong correlation was found between Polar and OEPS (r: 0.96, p < 0.001); the bias of BAA 0.85 bpm, the standard deviation (SD) 9.20 bpm, and the limits of agreement (LOA) from −17.18 bpm to +18.88 bpm. For the Mio-Alpha and OEPS, a strong correlation was found (r: 0.96, p < 0.001); the bias of BAA 1.63 bpm, SD 8.62 bpm, LOA from −15.27 bpm to +18.58 bpm. These results demonstrate the OEPS to be capable of carrying out real time and remote monitoring of heart rate. PMID:26473860

  4. Micro-optical design of a three-dimensional microlens scanner for vertically integrated micro-opto-electro-mechanical systems.

    PubMed

    Baranski, Maciej; Bargiel, Sylwester; Passilly, Nicolas; Gorecki, Christophe; Jia, Chenping; Frömel, Jörg; Wiemer, Maik

    2015-08-01

    This paper presents the optical design of a miniature 3D scanning system, which is fully compatible with the vertical integration technology of micro-opto-electro-mechanical systems (MOEMS). The constraints related to this integration strategy are considered, resulting in a simple three-element micro-optical setup based on an afocal scanning microlens doublet and a focusing microlens, which is tolerant to axial position inaccuracy. The 3D scanning is achieved by axial and lateral displacement of microlenses of the scanning doublet, realized by micro-electro-mechanical systems microactuators (the transmission scanning approach). Optical scanning performance of the system is determined analytically by use of the extended ray transfer matrix method, leading to two different optical configurations, relying either on a ball lens or plano-convex microlenses. The presented system is aimed to be a core component of miniature MOEMS-based optical devices, which require a 3D optical scanning function, e.g., miniature imaging systems (confocal or optical coherence microscopes) or optical tweezers.

  5. OptoDyCE as an automated system for high-throughput all-optical dynamic cardiac electrophysiology

    PubMed Central

    Klimas, Aleksandra; Ambrosi, Christina M.; Yu, Jinzhu; Williams, John C.; Bien, Harold; Entcheva, Emilia

    2016-01-01

    The improvement of preclinical cardiotoxicity testing, discovery of new ion-channel-targeted drugs, and phenotyping and use of stem cell-derived cardiomyocytes and other biologics all necessitate high-throughput (HT), cellular-level electrophysiological interrogation tools. Optical techniques for actuation and sensing provide instant parallelism, enabling contactless dynamic HT testing of cells and small-tissue constructs, not affordable by other means. Here we show, computationally and experimentally, the limits of all-optical electrophysiology when applied to drug testing, then implement and validate OptoDyCE, a fully automated system for all-optical cardiac electrophysiology. We validate optical actuation by virally introducing optogenetic drivers in rat and human cardiomyocytes or through the modular use of dedicated light-sensitive somatic ‘spark' cells. We show that this automated all-optical approach provides HT means of cellular interrogation, that is, allows for dynamic testing of >600 multicellular samples or compounds per hour, and yields high-content information about the action of a drug over time, space and doses. PMID:27161419

  6. Correlation between structural and opto-electronic characteristics of crystalline Si microhole arrays for photonic light management

    NASA Astrophysics Data System (ADS)

    Sontheimer, Tobias; Preidel, Veit; Lockau, Daniel; Back, Franziska; Rudigier-Voigt, Eveline; Löchel, Bernd; Erko, Alexei; Schmidt, Frank; Schnegg, Alexander; Lips, Klaus; Becker, Christiane; Rech, Bernd

    2013-11-01

    By employing electron paramagnetic resonance spectroscopy, transmission electron microscopy, and optical measurements, we systematically correlate the structural and optical properties with the deep-level defect characteristics of various tailored periodic Si microhole arrays, which are manufactured in an easily scalable and versatile process on nanoimprinted sol-gel coated glass. While tapered microhole arrays in a structured base layer are characterized by partly nanocrystalline features, poor electronic quality with a defect concentration of 1017 cm-3 and a high optical sub-band gap absorption, planar polycrystalline Si layers perforated with periodic arrays of tapered microholes are composed of a compact crystalline structure and a defect concentration in the low 1016 cm-3 regime. The low defect concentration is equivalent to the one in planar state-of-the-art solid phase crystallized Si films and correlates with a low optical sub-band gap absorption. By complementing the experimental characterization with 3-dimensional finite element simulations, we provide the basis for a computer-aided approach for the low-cost fabrication of novel high-quality structures on large areas featuring tailored opto-electronic properties.

  7. Synthesis of bi-phase dispersible core-shell FeAu@ZnO magneto-opto-fluorescent nanoparticles

    PubMed Central

    Li, Xue-Mei; Liu, Hong-Ling; Liu, Xiao; Fang, Ning; Wang, Xian-Hong; Wu, Jun-Hua

    2015-01-01

    Bi-phase dispersible core-shell FeAu@ZnO magneto-opto-fluorescent nanoparticles were synthesized by a modified nanoemulsion process using poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO) as the surfactant. The morphology and crystal structure of the nanoparticles were studied by TEM/HRTEM and XRD. The nanoparticles manifest soft ferromagnetic and/or near superparamagnetic behavior with a small coercivity of ~19 Oe at room temperature. The corresponding magnetic hysteresis curves were elucidated by the modified Langevin equation. The FTIR study confirms the PEO-PPO-PEO molecules on the surface of the nanoparticles. The UV-vis and PL results reveal the well-behaved absorption bands including surface plasmon resonance and multiple visible fingerprint photoluminescent emissions of the nanoparticles dispersed in both hydrophilic and hydrophobic solvents. Moreover, the processes of solvent dispersion-collection of the nanoparticles were demonstrated for application readiness of such core-shell nanostructures. PMID:26548369

  8. Opto-thermal measurements for the non-invasive, non-occlusive monitoring of in vivo skin condition.

    PubMed

    Bindra, R M; Imhof, R E; Andrew, J J; Cummins, P G; Eccleston, G M

    1995-06-01

    Summary Opto-thermal transient radiometry (OTTER) is a non-invasive measurement technique, well suited for in vivo skin research. Its excitation and detection wavelengths can be selected to give a high sensitivity to stratum corneum hydration. This is demonstrated with measurements of hydration changes resulting from occlusion with a neoprene cover and with a topical application of an occlusive preparation. In the former case, the hydration was found to recover to normal levels upon exposure to atmospheric conditions in a characteristic time of 15 min. In the latter case, a topical application of petroleum jelly was found to lead to a doubling of stratum corneum hydration over 2h. This ability to measure hydration changes in the presence of topical hydrating agents is thought to be a particularly valuable property of the OTTER technique. With a different choice of excitation and detection wavelengths, OTTER can be used to measure skin thickness, from the surface down to the vascular bed. This technique was used to measure a skin thickness map of the ventral surface of the forearm of a volunteer, showing distinct thickening near the wrist and ulna. Another use of this technique is the study of changes in subcutaneous blood distribution associated with erythema. As a demonstration of this, blood distribution changes brought about by the topical application of a salicylate/nicotinate preparation were studied. The main finding is that the subcutaneous blood spreads towards the surface, with the mean depth decreasing from 63 mum to 55mum.

  9. Outreach activities on light science and technology at TecnOpto-UMH during the International Year of Light

    NASA Astrophysics Data System (ADS)

    Sánchez-López, María. del Mar; García-Martínez, Pascuala; Espinosa, Rocío.; Carnicer, Jesús; Arias, Julia; Moreno, Ignacio

    2016-09-01

    TecnOpto is a group of researchers and teachers with interests in Optics and Photonics, located at the University Miguel Hernández (UMH) of Elche (Spain). Here we report on our outreach activities carried out during the International Year of Light - 2015. They include experiments and demonstrations at elementary and secondary schools, seminars and exhibitions at the university, and the activity named the "Classroom for the Experience", targeted to elder people. We also report on our participation in the science fair in Elche and in the launching of "the Room of Light", a complete new section of the MUDIC science museum devoted to light and optics. MUDIC is located in the UMH campus of Orihuela, and receives visitors from all over the region, mainly young students from elementary and secondary schools. Finally, we report on the exhibition "Women in Light Science and Light Technologies" which was organized by members of our group in collaboration with RSEF - the Spanish Royal Physical Society and SEDOPTICA - the Spanish Optical Society and sponsored by SPIE. This exhibition consisting of twelve posters on relevant women scientists was inaugurated in the XI Spanish Meeting on Optics and has travelled around many universities and cultural centers in Spain. A summary of the contents, participation and developing of all these activities is presented.

  10. A Comparative Study of Physiological Monitoring with a Wearable Opto-Electronic Patch Sensor (OEPS) for Motion Reduction

    PubMed Central

    Alzahrani, Abdullah; Hu, Sijung; Azorin-Peris, Vicente

    2015-01-01

    This paper presents a comparative study in physiological monitoring between a wearable opto-electronic patch sensor (OEPS) comprising a three-axis Microelectromechanical systems (MEMs) accelerometer (3MA) and commercial devices. The study aims to effectively capture critical physiological parameters, for instance, oxygen saturation, heart rate, respiration rate and heart rate variability, as extracted from the pulsatile waveforms captured by OEPS against motion artefacts when using the commercial probe. The protocol involved 16 healthy subjects and was designed to test the features of OEPS, with emphasis on the effective reduction of motion artefacts through the utilization of a 3MA as a movement reference. The results show significant agreement between the heart rates from the reference measurements and the recovered signals. Significance of standard deviation and error of mean yield values of 2.27 and 0.65 beats per minute, respectively; and a high correlation (0.97) between the results of the commercial sensor and OEPS. T, Wilcoxon and Bland-Altman with 95% limit of agreement tests were also applied in the comparison of heart rates extracted from these sensors, yielding a mean difference (MD: 0.08). The outcome of the present work incites the prospects of OEPS on physiological monitoring during physical activities. PMID:26061828

  11. Optoacoustic tweezers: a programmable, localized cell concentrator based on opto-thermally generated, acoustically activated, surface bubbles

    PubMed Central

    Zhao, Yanhui; Li, Sixing; Rufo, Joseph; Yang, Shikuan; Guo, Feng; Huang, Tony Jun

    2014-01-01

    We present a programmable, biocompatible technique for dynamically concentrating and patterning particles and cells in a microfluidic device. Since our technique utilizes opto-thermally generated, acoustically activated, surface bubbles, we name it “optoacoustic tweezers.” The optoacoustic tweezers are capable of concentrating particles/cells at any prescribed locations in a microfluidic chamber without the use of permanent structures, rendering it particularly useful for the formation of flexible, complex cell patterns. Additionally, this technique has demonstrated excellent biocompatibility and can be conveniently integrated with other microfluidic units. In our experiments, micro-bubbles were generated by focusing a 405 nm diode laser onto a gold-coated glass chamber. By properly tuning the laser, we demonstrate precise control over the position and size of the generated bubbles. Acoustic waves were then applied to activate the surface bubbles, causing them to oscillate at an optimized frequency. The resulting acoustic radiation force allowed us to locally trap particles/cells, including 15 μm polystyrene beads and HeLa cells, around each bubble. Cell-adhesion tests were also conducted after cell concentrating to confirm the biocompatibility of this technique. PMID:23511348

  12. Correlation between structural and opto-electronic characteristics of crystalline Si microhole arrays for photonic light management

    SciTech Connect

    Sontheimer, Tobias Schnegg, Alexander; Lips, Klaus; Rech, Bernd; Preidel, Veit; Becker, Christiane; Lockau, Daniel; Back, Franziska; Rudigier-Voigt, Eveline; Löchel, Bernd; Erko, Alexei; Schmidt, Frank

    2013-11-07

    By employing electron paramagnetic resonance spectroscopy, transmission electron microscopy, and optical measurements, we systematically correlate the structural and optical properties with the deep-level defect characteristics of various tailored periodic Si microhole arrays, which are manufactured in an easily scalable and versatile process on nanoimprinted sol-gel coated glass. While tapered microhole arrays in a structured base layer are characterized by partly nanocrystalline features, poor electronic quality with a defect concentration of 10{sup 17} cm{sup −3} and a high optical sub-band gap absorption, planar polycrystalline Si layers perforated with periodic arrays of tapered microholes are composed of a compact crystalline structure and a defect concentration in the low 10{sup 16} cm{sup −3} regime. The low defect concentration is equivalent to the one in planar state-of-the-art solid phase crystallized Si films and correlates with a low optical sub-band gap absorption. By complementing the experimental characterization with 3-dimensional finite element simulations, we provide the basis for a computer-aided approach for the low-cost fabrication of novel high-quality structures on large areas featuring tailored opto-electronic properties.

  13. Synthesis of bi-phase dispersible core-shell FeAu@ZnO magneto-opto-fluorescent nanoparticles

    NASA Astrophysics Data System (ADS)

    Li, Xue-Mei; Liu, Hong-Ling; Liu, Xiao; Fang, Ning; Wang, Xian-Hong; Wu, Jun-Hua

    2015-11-01

    Bi-phase dispersible core-shell FeAu@ZnO magneto-opto-fluorescent nanoparticles were synthesized by a modified nanoemulsion process using poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO) as the surfactant. The morphology and crystal structure of the nanoparticles were studied by TEM/HRTEM and XRD. The nanoparticles manifest soft ferromagnetic and/or near superparamagnetic behavior with a small coercivity of ~19 Oe at room temperature. The corresponding magnetic hysteresis curves were elucidated by the modified Langevin equation. The FTIR study confirms the PEO-PPO-PEO molecules on the surface of the nanoparticles. The UV-vis and PL results reveal the well-behaved absorption bands including surface plasmon resonance and multiple visible fingerprint photoluminescent emissions of the nanoparticles dispersed in both hydrophilic and hydrophobic solvents. Moreover, the processes of solvent dispersion-collection of the nanoparticles were demonstrated for application readiness of such core-shell nanostructures.

  14. A Comparative Study of Physiological Monitoring with a Wearable Opto-Electronic Patch Sensor (OEPS) for Motion Reduction.

    PubMed

    Alzahrani, Abdullah; Hu, Sijung; Azorin-Peris, Vicente

    2015-06-08

    This paper presents a comparative study in physiological monitoring between a wearable opto-electronic patch sensor (OEPS) comprising a three-axis Microelectromechanical systems (MEMs) accelerometer (3MA) and commercial devices. The study aims to effectively capture critical physiological parameters, for instance, oxygen saturation, heart rate, respiration rate and heart rate variability, as extracted from the pulsatile waveforms captured by OEPS against motion artefacts when using the commercial probe. The protocol involved 16 healthy subjects and was designed to test the features of OEPS, with emphasis on the effective reduction of motion artefacts through the utilization of a 3MA as a movement reference. The results show significant agreement between the heart rates from the reference measurements and the recovered signals. Significance of standard deviation and error of mean yield values of 2.27 and 0.65 beats per minute, respectively; and a high correlation (0.97) between the results of the commercial sensor and OEPS. T, Wilcoxon and Bland-Altman with 95% limit of agreement tests were also applied in the comparison of heart rates extracted from these sensors, yielding a mean difference (MD: 0.08). The outcome of the present work incites the prospects of OEPS on physiological monitoring during physical activities.

  15. Pixel-based OPC optimization based on conjugate gradients.

    PubMed

    Ma, Xu; Arce, Gonzalo R

    2011-01-31

    Optical proximity correction (OPC) methods are resolution enhancement techniques (RET) used extensively in the semiconductor industry to improve the resolution and pattern fidelity of optical lithography. In pixel-based OPC (PBOPC), the mask is divided into small pixels, each of which is modified during the optimization process. Two critical issues in PBOPC are the required computational complexity of the optimization process, and the manufacturability of the optimized mask. Most current OPC optimization methods apply the steepest descent (SD) algorithm to improve image fidelity augmented by regularization penalties to reduce the complexity of the mask. Although simple to implement, the SD algorithm converges slowly. The existing regularization penalties, however, fall short in meeting the mask rule check (MRC) requirements often used in semiconductor manufacturing. This paper focuses on developing OPC optimization algorithms based on the conjugate gradient (CG) method which exhibits much faster convergence than the SD algorithm. The imaging formation process is represented by the Fourier series expansion model which approximates the partially coherent system as a sum of coherent systems. In order to obtain more desirable manufacturability properties of the mask pattern, a MRC penalty is proposed to enlarge the linear size of the sub-resolution assistant features (SRAFs), as well as the distances between the SRAFs and the main body of the mask. Finally, a projection method is developed to further reduce the complexity of the optimized mask pattern.

  16. A CMOS Active Pixel Sensor for Charged Particle Detection

    SciTech Connect

    Matis, Howard S.; Bieser, Fred; Kleinfelder, Stuart; Rai, Gulshan; Retiere, Fabrice; Ritter, Hans George; Singh, Kunal; Wurzel, Samuel E.; Wieman, Howard; Yamamoto, Eugene

    2002-12-02

    Active Pixel Sensor (APS) technology has shown promise for next-generation vertex detectors. This paper discusses the design and testing of two generations of APS chips. Both are arrays of 128 by 128 pixels, each 20 by 20 {micro}m. Each array is divided into sub-arrays in which different sensor structures (4 in the first version and 16 in the second) and/or readout circuits are employed. Measurements of several of these structures under Fe{sup 55} exposure are reported. The sensors have also been irradiated by 55 MeV protons to test for radiation damage. The radiation increased the noise and reduced the signal. The noise can be explained by shot noise from the increased leakage current and the reduction in signal is due to charge being trapped in the epi layer. Nevertheless, the radiation effect is small for the expected exposures at RHIC and RHIC II. Finally, we describe our concept for mechanically supporting a thin silicon wafer in an actual detector.

  17. Solution processed integrated pixel element for an imaging device

    NASA Astrophysics Data System (ADS)

    Swathi, K.; Narayan, K. S.

    2016-09-01

    We demonstrate the implementation of a solid state circuit/structure comprising of a high performing polymer field effect transistor (PFET) utilizing an oxide layer in conjunction with a self-assembled monolayer (SAM) as the dielectric and a bulk-heterostructure based organic photodiode as a CMOS-like pixel element for an imaging sensor. Practical usage of functional organic photon detectors requires on chip components for image capture and signal transfer as in the CMOS/CCD architecture rather than simple photodiode arrays in order to increase speed and sensitivity of the sensor. The availability of high performing PFETs with low operating voltage and photodiodes with high sensitivity provides the necessary prerequisite to implement a CMOS type image sensing device structure based on organic electronic devices. Solution processing routes in organic electronics offers relatively facile procedures to integrate these components, combined with unique features of large-area, form factor and multiple optical attributes. We utilize the inherent property of a binary mixture in a blend to phase-separate vertically and create a graded junction for effective photocurrent response. The implemented design enables photocharge generation along with on chip charge to voltage conversion with performance parameters comparable to traditional counterparts. Charge integration analysis for the passive pixel element using 2D TCAD simulations is also presented to evaluate the different processes that take place in the monolithic structure.

  18. Thin hybrid pixel assembly fabrication development with backside compensation layer

    NASA Astrophysics Data System (ADS)

    Bates, R.; Buttar, C.; McMullen, T.; Cunningham, L.; Ashby, J.; Doherty, F.; Pares, G.; Vignoud, L.; Kholti, B.; Vahanen, S.

    2017-02-01

    The ATLAS and CMS experiments will both replace their entire tracking systems for operation at the HL-LHC in 2026. This will include a significantly larger pixel systems, for example, for ATLAS approximately 15 m2. To keep the tracker material budget low it is crucial to minimize the mass of the pixel modules via thinning both the sensor and readout chip to about 150 μm each. The bump yield of thin module assemblies using solder based bump bonding can be problematic due to wafer bowing during solder reflow at high temperature. A new bump-bonding process using backside compensation on the readout chip to address the issue of low yield will be presented. The objective is to compensate dynamically the stress of the front side stack by adding a compensating layer to the backside of the wafer. A SiN and Al:Si stack has been chosen for the backside layer. The bow reducing effect of applying a backside compensation layer will be demonstrated using the FE-I4 wafer. The world's first results from assemblies produced from readout wafers thinned to 100 μm with a stress compensation layer are presented with bond yields close to 100% measured using the FE-I4 readout chip.

  19. Single pixel optical imaging using a scanning MEMS mirror

    NASA Astrophysics Data System (ADS)

    Li, Li; Stankovic, Vladimir; Stankovic, Lina; Li, Lijie; Cheng, Samuel; Uttamchandani, Deepak

    2011-02-01

    The paper describes a low-complexity optical imaging system using demagnifying optics, a single scanning MEMS mirror and a single photodetector. Light at visible wavelengths from the object passes through a lens assembly and is incident on a scanning MEMS micromirror. After reflection from the micromirror, a complete image of the object is projected at the image plane of the optical system where a single-element photodetector with a pinhole at its entrance is located. By tilting the micromirror in the x and y directions, the projected image is translated across the image plane in the x and y directions. The photodetector sequentially detects the intensity of different areas of the projected optical image, thereby enabling a digital image to be generated pixel-by-pixel. However, due to the noisy raw image obtained experimentally, an image enhancement algorithm based on iterative-combined wavelet and curvelet denoising has been developed. Using blind image quality indices (BIQI) as an objective performance measure, it is shown that the proposed image enhancement method enhances the raw image by up to 40% and outperforms state-of-the-art denoising methods for up to 10 units of BIQI.

  20. Multilayer fluorescence imaging on a single-pixel detector

    PubMed Central

    Guo, Kaikai; Jiang, Shaowei; Zheng, Guoan

    2016-01-01

    A critical challenge for fluorescence imaging is the loss of high frequency components in the detection path. Such a loss can be related to the limited numerical aperture of the detection optics, aberrations of the lens, and tissue turbidity. In this paper, we report an imaging scheme that integrates multilayer sample modeling, ptychography-inspired recovery procedures, and lensless single-pixel detection to tackle this challenge. In the reported scheme, we directly placed a 3D sample on top of a single-pixel detector. We then used a known mask to generate speckle patterns in 3D and scanned this known mask to different positions for sample illumination. The sample was then modeled as multiple layers and the captured 1D fluorescence signals were used to recover multiple sample images along the z axis. The reported scheme may find applications in 3D fluorescence sectioning, time-resolved and spectrum-resolved imaging. It may also find applications in deep-tissue fluorescence imaging using the memory effect. PMID:27446679