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Sample records for analysis photon activation

  1. Activation analysis using {gamma} photons; Analyse par activation aux photons {gamma}

    Energy Technology Data Exchange (ETDEWEB)

    Engelmann, Ch. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-07-01

    This report summarizes all the data required for using photonuclear reactions in the field of analysis. After a brief review of the elementary properties of nuclear reactions induced by photon irradiation, the main characteristics are given of high energy (E > 20 MeV) Bremsstrahlung sources. The principle of activation analysis based on the use of photons is given. Actual examples of the analytic possibilities are described in detail, in particular in the case of the determination of very small quantities (< 10{sup -6}) of C, N, O and F. The influence of interfering nuclear reactions is discussed. (author) [French] Ce rapport se propose de resumer l'ensemble des connaissances indispensables pour l'utilisation des reactions photonucleaires a des fins analytiques. Apres quelques rappels concernant les proprietes elementaires des reactions nucleaires induites par irradiation dans les photons, les principales caracteristiques des sources de rayonnement de freinage de haute energie (E > 20 MeV)| sont donnees. Le principe de l'analyse par activation aux photons est rappele. Des exemples concrets sur les possibilites analytiques sont developpes, particulierement en ce qui concerne la determination de quantites tres faibles (< 10{sup -6}) de C, N, O et F. L'influence des reactions nucleaires parasites est discutee. (auteur)

  2. Radiochemical photon activation analysis of Halogens in meteorites

    Energy Technology Data Exchange (ETDEWEB)

    Oura, Yasuji; Latif, S.A.; Setoguchi, Mina; Nakamoto, Tomoshi; Ebihara, Mitsuru; Nakahara, Hiromichi [Tokyo Metropolitan Univ. (Japan). Faculty of Science; Ohtsuki, Tsutomu

    1999-12-01

    Halogens (F, Cl, Br and I) in meteorites and rocks are determined by a radiochemical photon activation analysis (RPAA) and compared with that of NPAA. We tried to determine all halogen elements at one time by one irradiation with 20 or 30 MeV maximum energy (E{sub 0}) by controlling irradiation for 2 or 6 hours with cooling. Average current is about 110 {mu}A. After irradiation, the sample was separated by radiochemical analysis. Allende meteorite, JR-I and d-41-7 were analyzed. The value of F, Cl and Br showed good reproducibility and agreed with the value in the reference. However, I showed small value. It may indicate volatilizing of I. (S.Y.)

  3. Active Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Ek, Sara

    This thesis deals with the fabrication and characterization of active photonic crystal waveguides, realized in III-V semiconductor material with embedded active layers. The platform offering active photonic crystal waveguides has many potential applications. One of these is a compact photonic...... crystal semiconductor optical amplier. As a step towards such a component, photonic crystal waveguides with a single quantum well, 10 quantum wells and three layers of quantum dots are fabricated and characterized. An experimental study of the amplied spontaneous emission and a implied transmission...... due to photonic crystal dispersion. The observations are explained by the enhancement of net gain by light slow down. Another application based on active photonic crystal waveguides is micro lasers. Measurements on quantum dot micro laser cavities with different mirror configurations and photonic...

  4. Determination of nitrogen in boron carbide by instrumental photon activation analysis.

    Science.gov (United States)

    Merchel, Silke; Berger, Achim

    2007-05-01

    Boron carbide is widely used as industrial material, because of its extreme hardness, and as a neutron absorber. As part of a round-robin exercise leading to certification of a new reference material (ERM-ED102) which was demanded by the industry we analysed nitrogen in boron carbide by inert gas fusion analysis (GFA) and instrumental photon activation analysis (IPAA) using the 14N(gamma,n)13N nuclear reaction. The latter approach is the only non-destructive method among all the methods applied. By using photons with energy below the threshold of the 12C(gamma,n)11C reaction, we hindered activation of matrix and other impurities. A recently installed beam with a very low lateral activating flux gradient enabled us to homogeneously activate sample masses of approximately 1 g. Taking extra precautions, i.e. self-absorption correction and deconvolution of the complex decay curves, we calculated a nitrogen concentration of 2260+/-100 microg g-1, which is in good agreement with our GFA value of 2303+/-64 microg g-1. The values are the second and third highest of a rather atypical (non-S-shape) distribution of data of 14 round-robin participants. It is of utmost importance for the certification process that our IPAA value is the only one not produced by inert gas fusion analysis and, therefore, the only one which is not affected by a possible incomplete release of nitrogen from high-melting boron carbide.

  5. Determination of Interesting Toxicological Elements in PM2.5 by Neutron and Photon Activation Analysis

    Directory of Open Access Journals (Sweden)

    Pasquale Avino

    2013-01-01

    Full Text Available Human activities introduce compounds increasing levels of many dangerous species for environment and population. In this way, trace elements in airborne particulate have a preeminent position due to toxic element presence affecting the biological systems. The main problem is the analytical determination of such species at ultratrace levels: a very specific methodology is necessary with regard to the accuracy and precision and contamination problems. Instrumental Neutron Activation Analysis and Instrumental Photon Activation Analysis assure these requirements. A retrospective element analysis in airborne particulate collected in the last 4 decades has been carried out for studying their trend. The samples were collected in urban location in order to determine only effects due to global aerosol circulation; semiannual samples have been used to characterize the summer/winter behavior of natural and artificial origin. The levels of natural origin element are higher than those in other countries owing to geological and meteorological factors peculiar to Central Italy. The levels of artificial elements are sometimes less than those in other countries, suggesting a less polluted general situation for Central Italy. However, for a few elements (e.g., Pb the levels measured are only slight lower than those proposed as air ambient standard.

  6. Silicon active photonic devices

    Science.gov (United States)

    Dimitropoulos, Dimitrios

    Active photonic devices utilizing the optical nonlinearities of silicon have emerged in the last 5 years and the effort for commercial photonic devices in the material that has been the workhorse of electronics has been building up since. This dissertation presents the theory for some of these devices. We are concerned herein with CW lasers, amplifiers and wavelength converters that are based on the Raman effect. There have already been cursory experimental demonstrations of these devices and some of their limitations are already apparent. Most of the limitations observed are because of the appearance of effects that are competing with stimulated Raman scattering. Under the high optical powers that are necessary for the Raman effect (tens to hundrends of mW's) the process of optical two-photon (TPA) absorption occurs. The absorption of optical power that it causes itself is weak but in the process electrons and holes are generated which can further absorb light through the free-carrier absorption effect (FCA). The effective "lifetime" that these carriers have determines the magnitude of the FCA loss. We present a model for the carrier lifetime in Silicon-On-Insulator (SOI) waveguides and numerical simulations to understand how this critical parameter varies and how it can be controlled. A p-i-n junction built along SOI waveguides can help achieve lifetime of the order of 20--100 ps but the price one has to pay is on-chip electrical power consumption on the order of 100's of mWs. We model CW Raman lasers and we find that the carrier lifetime reduces the output power. If the carrier lifetime exceeds a certain "critical" value optical losses become overwhelming and lasing is impossible. As we show, in amplifiers, the nonlinear loss does not only result in diminished gain, but also in a higher noise figure. Finally the effect of Coherent anti-Stokes Raman scattering (CARS) is examined. The effect is important because with a pump frequency at 1434nm coherent power

  7. Phoswich detectors with DSP analysis for low-energy, low-activity photon measurements

    Energy Technology Data Exchange (ETDEWEB)

    Pillai, S.; Feng, J.; Miller, W.H. [Univ. of Missouri, Columbia, MO (United States)

    1999-09-01

    Several new phoswich detector designs coupled with digital pulse shape discrimination systems are under development for a variety of radiological measurements. Herein the authors report on two detectors for measuring small activities (nanocurie amounts) of low photon energy (30 to 150 keV) from either isotopic decay or beta-produced bremsstrahlung radiation. The lower limit of detection (LLD), assuming a 60-s counting time, for a phoswich well detector is 0.7 Bq (0.02 nCi) of gamma activity in the 20- to 100-keV range and 11 Bq (0.3 nCi) and 550 (15 nCi) for gamma rays and beta bremsstrahlung X rays, respectively. It is envisioned that these detectors would be useful for biomedical applications or for other measurements requiring low-level, low-energy photon measurement.

  8. Photonics activities at DTU Fotonik

    DEFF Research Database (Denmark)

    Jeppesen, Palle; Jepsen, Peter Uhd; Lodahl, Peter;

    2010-01-01

    DTU Fotonik, Department of Photonics Engineering at the Technical University of Denmark has about 200 employees including 60 PhD students. The ambition is to be among the world’s leading University departments within photonics research, education and innovation. To fulfil this ambition, DTU Fotonik...... tries to attract excellent researchers and students from all over the world and to collaborate with world leading research institutes and companies. The activities span from quantum photonics, nanotechnology and metamaterials over nonlinear fiber optics, optical sensors and diode lasers & LED systems...

  9. Photon Factory Activity Report, 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    Photon Factory Activity Report no.12 deals with our activities in the period from October 1993 through September 1994. We operate two light sources at the Photon Factory; the 2.5-GeV Photon Factory storage ring, which is a dedicated light source, and the 6.5-GeV TRISTAN Accumulation Ring, which is parasitically used as a light source. We keep more than seventy experimental stations at two facilities, and accept experiments primarily according to approval by the Program Advisory Committee. The number of proposals to the Photon Factory has been still growing. Three-hundred eighty two proposals were approved by the PAC in FY1994, which is an increase by thirteen percent compared to the previous year. Remarkable was growth in biology proposals, particularly proposals in protein crystallography. In FY 1994, we accepted approximately 20,000 man-days as general users, and almost ten percent of them were from abroad. We always open the facility to users, not only domestic but also international. Recently we have been concentrating our effort to upgrading of the light sources and reconstruction of the experimental stations to keep the Photon Factory an attractive research facility in the forthcoming years. We have already started a program of reducing the emittance of the 2.5-GeV storage ring, which now operates with an emittance of 110 nm-rad, to 27 nm-rad by modifying the lattice, with the goal of operation at the reduced emittance in the fall of 1997. We also have conceived of a conversion of the TRISTAN Accumulation Ring to a dedicated light source of high energies. The on-going TRISTAN project will terminate by the end of 1995, and the TRISTAN Main Ring will be converted to a new B-Factory. At this moment, the TRISTAN Accumulation Ring will be disused as the injector to the Main Ring, and conversion of the AR to a dedicated light source becomes possible. (J.P.N.)

  10. Analysis of the swimming activity of Pseudomonas aeruginosa by using photonic force microscope

    Science.gov (United States)

    Chan, Chia-Han; Chang, Bo-Jui; Huang, Ying-Jung; Fan, Chia-Chieh; Peng, Hwei-Ling; Chi, Sien; Hsu, Long

    2005-08-01

    Swimming activity of flagella is a main factor of the motility of bacteria. Flagella expressed on the surface of bacterial species serve as a primary means of motility including swimming. We propose to use optical tweezers to analyze the swimming activity of bacteria. The sample bacteria in the work is Pseudomonas aeruginosa, and it is a gram-negative bacterium and often causes leading to burn wound infections, urinary-tract infections, and pneumonia. The single polar flagellum of P. aeruginosa has been demonstrated to be important virulence and colonization factor of this opportunistic pathogen. We demonstrate a gene to regulate the bacterial swimming activity in P. aeruginosa PAO1 by biological method. However, the change of flagellar morphology was not observed by electron microscopy analysis, suggesting that the gene regulates the flagellar rotation that could not be detected by biological method. PFM exhibits a spatial resolution of a few nanometers to detect the relative position of the probe at an acquisition rate over 1 MHz. By binding a probe such as a bead or a quantum dot on the flagella, we expect the rotation of the probe due to the flagella could be detected. It is expected that the study of the swimming activity of P. aeruginosa provide potent method for the pathogenic role of the flagella in P. aeruginosa.

  11. Distributed Feedback Effects in Active Semiconductor Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2012-01-01

    We present a rigorous coupled-wave analysis of slow-light effects in active photonic crystal waveguides. The presence of active material leads to coherent distributed feedback effects that significantly alter the magnitude and phase of output fields.......We present a rigorous coupled-wave analysis of slow-light effects in active photonic crystal waveguides. The presence of active material leads to coherent distributed feedback effects that significantly alter the magnitude and phase of output fields....

  12. Photon activation analysis of trace elements in several kinds of invertebrate animals. 1. Arthropoda crustacea

    Energy Technology Data Exchange (ETDEWEB)

    Fukushima, Michiko; Tamate, Hidetoshi [Ishinomaki Senshu Univ., Miyagi (Japan)

    1998-09-01

    Quantitative analysis of trace elements was made for marine mollusca by light quantum activation method. Crustacea which is likely to be well reflecting the environment of ocean floor was used as the subjects. Various kinds of these animals including Carcinus Portunus. Palinurus, Panulirus, Squilla etc. were collected from the sea off Japan to determine the concentrations of 15 kinds of elements in the gills, muscles, head/thorax region and viceraneous organs. The concentration of As was found markedly high in either of gills, muscles or viceraneous organs of Palinurus taken from the sea near Okinawa. It was found that there are no difference in the concentrations of As, Fe, Mn and Pb among the species studied and Fe, Mn and Pb were detected at high levels in the gills of Carcinus, whereas the Fe and Mn concentrations in the gills of Palinurus were considerably lower than other species tested. Thus, the element concentration was different among the regions studied and also species. (M.N.)

  13. Proof-of-principle results for identifying the composition of dust particles and volcanic ash samples through the technique of photon activation analysis at the IAC

    Science.gov (United States)

    Mamtimin, Mayir; Cole, Philip L.; Segebade, Christian

    2013-04-01

    Instrumental analytical methods are preferable in studying sub-milligram quantities of airborne particulates collected in dust filters. The multi-step analytical procedure used in treating samples through chemical separation can be quite complicated. Further, due to the minute masses of the airborne particulates collected on filters, such chemical treatment can easily lead to significant levels of contamination. Radio-analytical techniques, and in particular, activation analysis methods offer a far cleaner alternative. Activation methods require minimal sample preparation and provide sufficient sensitivity for detecting the vast majority of the elements throughout the periodic table. In this paper, we will give a general overview of the technique of photon activation analysis. We will show that by activating dust particles with 10- to 30-MeV bremsstrahlung photons, we can ascertain their elemental composition. The samples are embedded in dust-collection filters and are irradiated "as is" by these photons. The radioactivity of the photonuclear reaction products is measured with appropriate spectrometers and the respective analytes are quantified using multi-component calibration materials. We shall provide specific examples of identifying the elemental components of airborne dust particles and volcanic ash by making use of bremsstrahlung photons from an electron linear accelerator at the Idaho Accelerator Center in Pocatello, Idaho.

  14. Simulation of Nonlinear Gain Saturation in Active Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2012-01-01

    In this paper we present a theoretical analysis of slowlight enhanced traveling wave amplification in an active semiconductor Photonic crystal waveguides. The impact of group index on nonlinear modal gain saturation is investigated.......In this paper we present a theoretical analysis of slowlight enhanced traveling wave amplification in an active semiconductor Photonic crystal waveguides. The impact of group index on nonlinear modal gain saturation is investigated....

  15. Nonlinear Gain Saturation in Active Slow Light Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2013-01-01

    We present a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguides. The impact of slow-light propagation on the nonlinear gain saturation of the device is investigated.......We present a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguides. The impact of slow-light propagation on the nonlinear gain saturation of the device is investigated....

  16. Nondestructive assay of fluorine in geological and other materials by instrumental photon activation analysis with a microtron

    Energy Technology Data Exchange (ETDEWEB)

    Krausová, Ivana [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež 130, 25068 Řež (Czech Republic); Mizera, Jiří, E-mail: mizera@ujf.cas.cz [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež 130, 25068 Řež (Czech Republic); Institute of Rock Structure and Mechanics, Academy of Sciences of the Czech Republic, V Holešovičkách 41, 182 09 Praha 8 (Czech Republic); Řanda, Zdeněk; Chvátil, David; Krist, Pavel [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež 130, 25068 Řež (Czech Republic)

    2015-01-01

    Reliable determination of low concentrations of fluorine in geological and coal samples is difficult. It usually requires tedious decomposition and dissolution of the sample followed by chemical conversion of fluorine into its anionic form. The present paper examines possibilities of non-destructive determination of fluorine, mainly in minerals, rocks and coal, by instrumental photon activation analysis (IPAA) using the MT-25 microtron. The fluorine assay consists of counting the positron–electron annihilation line of {sup 18}F at 511 keV, which is a product of the photonuclear reaction {sup 19}F(γ, n){sup 18}F and a pure positron emitter. The assay is complicated by the simultaneous formation of other positron emitters. The main contributors to interference in geological samples are from {sup 45}Ti and {sup 34m}Cl, whereas those from {sup 44}Sc and {sup 89}Zr are minor. Optimizing beam energy and irradiation-decay-counting times, together with using interfering element calibration standards, allowed reliable IPAA determination of fluorine in selected USGS and CRPG geochemical reference materials, NIST coal reference materials, and NIST RM 8414 Bovine Muscle. In agreement with the published data obtained by PIGE, the results of the F assay by IPAA have revealed erroneous reference values provided for the NIST reference materials SRM 1632 Bituminous Coal and RM 8414 Bovine Muscle. The detection limits in rock and coal samples are in the range of 10–100 μg g{sup −1}.

  17. Nondestructive assay of fluorine in geological and other materials by instrumental photon activation analysis with a microtron

    Science.gov (United States)

    Krausová, Ivana; Mizera, Jiří; Řanda, Zdeněk; Chvátil, David; Krist, Pavel

    2015-01-01

    Reliable determination of low concentrations of fluorine in geological and coal samples is difficult. It usually requires tedious decomposition and dissolution of the sample followed by chemical conversion of fluorine into its anionic form. The present paper examines possibilities of non-destructive determination of fluorine, mainly in minerals, rocks and coal, by instrumental photon activation analysis (IPAA) using the MT-25 microtron. The fluorine assay consists of counting the positron-electron annihilation line of 18F at 511 keV, which is a product of the photonuclear reaction 19F(γ, n)18F and a pure positron emitter. The assay is complicated by the simultaneous formation of other positron emitters. The main contributors to interference in geological samples are from 45Ti and 34mCl, whereas those from 44Sc and 89Zr are minor. Optimizing beam energy and irradiation-decay-counting times, together with using interfering element calibration standards, allowed reliable IPAA determination of fluorine in selected USGS and CRPG geochemical reference materials, NIST coal reference materials, and NIST RM 8414 Bovine Muscle. In agreement with the published data obtained by PIGE, the results of the F assay by IPAA have revealed erroneous reference values provided for the NIST reference materials SRM 1632 Bituminous Coal and RM 8414 Bovine Muscle. The detection limits in rock and coal samples are in the range of 10-100 μg g-1.

  18. Optical properties of active photonic materials

    OpenAIRE

    Zeng, Yong

    2007-01-01

    Because of the generation of polaritons, which are quasiparticles possessing the characteristics of both photonics and electronics, active photonic materials offer a possible solution to transfer electromagnetic energy below the diffraction limit and further increase the density of photonic integrated circuits. A theoretical investigation of these exciting materials is, therefore, very important for practical applications. Four different kinds of polaritons have been studied in this thesis, (...

  19. Photon Factory activity report, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    The Photon Factory at the National Laboratory for High Energy Physics is a national facility for scientific research utilizing synchrotron radiation. Although the Photon Factory operator the linear injector, two light sources including the 2.5 GeV storage ring and the 6.5 GeV TRISTAN accumulation Ring as well as a major fraction of their beamlines and experimental station. This report is covered the period from October 1994 to September 1995. The total number of proposals by this PAC was 399 in 1995. Facility development projects currently in progress include the following, TRISTAN Super Light Facility (TSLF) project, VUV-FEL project, KEKB project and Slow-positron Source. This report contents outline of the Photon Factory, introduction, scientific disciplines, electronic properties of condensed matters, atomic and molecular science, X-ray imaging, radiobiology using synchrotron radiation, structural properties of condensed matters, structural properties of solid surfaces and adsorbates, structure and function of proteins, theoretical researches, experimental facilities, beamlines, new instrumentation, AR Upgrade, collaborations, projects, user`s short reports, list of published papers 1994/95. (S.Y.)

  20. Manufacturing cost analysis of integrated photonic packages

    Science.gov (United States)

    Stirk, Charles W.; Liu, Qin; Ball, Matthew V.

    1999-04-01

    This paper analyzes the manufacturing cost of photonic system using software that combines several methods for accurate cost accounting. Activity based costing assigns al capital equipment, material and labor costs directly to the product rather than to overheads. Cost of ownership models determine the cost of using machines under different financial and utilization scenarios. Libraries of standard machines, process steps, and process sequences facilitate rapid model building and modification. Using libraries for semiconductor and photonics fabrication, along with packaging and optomechanical assembly, we construct cost models for 2D VCSEL array communication modules. The result of the analysis is that the model cost is driven mainly by the epitaxial material cost, and laser yield limits VCSEL arrays to small scale integration.

  1. Photonic crystal fibers for food quality analysis

    Science.gov (United States)

    Malinin, A. V.; Zanishevskaja, A. A.; Tuchin, V. V.; Skibina, Yu. S.; Silokhin, I. Y.

    2012-06-01

    The aspects of application of the hollow core photonic crystal waveguides for spectroscopic analysis of liquid medium were considered. The possibility of using these structures for analysis of a fruit juice was evaluated. The principles of processing of photonic crystal waveguide transmission spectra, which is sensitive to quality of juice, its composition, and main component concentration, were revealed.

  2. The PHOTON explorations: sixteen activities, many uses

    Science.gov (United States)

    Donnelly, Judith; Amatrudo, Kathryn; Robinson, Kathleen; Hanes, Fenna

    2014-07-01

    The PHOTON Explorations were adapted from favorite demonstrations of teacher participants in the PHOTON projects of the New England Board of Higher Education as well as Hands-on-Optics activities and interesting demonstrations found on the web. Since the end of project PHOTON2 in 2006, the sixteen inquiry-based activities have formed the basis for a hands-on "home lab" distance- learning course that has been used for college students, teacher professional development and corporate training. With the support of OSA, they have been brought to life in a series of sixteen short videos aimed at a middle school audience. The Explorations are regularly used as activities in outreach activities for middle and high school students and are introduced yearly to an international audience at an outreach workshop at SPIE's Optics and Photonics meeting. In this paper we will demonstrate the Explorations, trace their origins and explain the content. We will also provide details on the development of the Exploration videos, the online course, and outreach materials and give statistics on their use in each format. Links to online resources will be provided.

  3. Exploring neuronal activity with photons

    Science.gov (United States)

    Bourdieu, Laurent; Léger, Jean-François

    2015-10-01

    The following sections are included: * Introduction * Information coding * Optical recordings of neuronal activity * Functional organization of the cortex at the level of a cortical column * Microarchitecture of a cortical column * Dynamics of neuronal populations * Outlook * Bibliography

  4. Active learning in optics and photonics

    Science.gov (United States)

    Niemela, Joseph J.

    2016-09-01

    Active learning in optics and photonics (ALOP) is a program of the International Basic Sciences Program at UNESCO, in collaboration with the Abdus Salam International Centre for Theoretical Physics (ICTP) and supported by SPIE, which is designed to help teachers in the developing world attract and retain students in the physical sciences. Using optics and photonics, it naturally attracts the interest of students and can be implemented using relatively low cost technologies, so that it can be more easily reproduced locally. The active learning methodology is student-centered, meaning the teachers give up the role of lecturer in favor of guiding and facilitating a learning process in which students engage in hands-on activities and active peer-peer discussions, and is shown to effectively enhance basic conceptual understanding of physics.

  5. Non-line-of-sight active imaging of scattered photons

    Science.gov (United States)

    Laurenzis, Martin; Velten, Andreas

    2013-10-01

    Laser Gated Viewing is a prominent sensing technology for optical imaging in harsh environments and can be applied to the vision through fog, smoke and other degraded environmental conditions as well as to the vision through sea water in submarine operation. A direct imaging of non-scattered photons (or ballistic photons) is limited in range and performance by the free optical path length i.e. the length in which a photon can propagate without interaction with scattering particles or object surfaces. The imaging and analysis of scattered photons can overcome these classical limitations and it is possible to realize a non-line-of-sight imaging. The spatial and temporal distribution of scattered photons can be analyzed by means of computational optics and their information of the scenario can be restored. In the case of Lambertian scattering sources the scattered photons carry information of the complete environment. Especial the information outside the line of sight or outside the visibility range is of high interest. Here, we discuss approaches for non line of sight active imaging with different indirect and direct illumination concepts (point, surface and volume scattering sources).

  6. Photonic Crystals Mathematical Analysis and Numerical Approximation

    CERN Document Server

    Dörfler, Willy; Plum, Michael; Schneider, Guido; Wieners, Christian

    2011-01-01

    This book concentrates on the mathematics of photonic crystals, which form an important class of physical structures investigated in nanotechnology. Photonic crystals are materials which are composed of two or more different dielectrics or metals, and which exhibit a spatially periodic structure, typically at the length scale of hundred nanometers. In the mathematical analysis and the numerical simulation of the partial differential equations describing nanostructures, several mathematical difficulties arise, e. g., the appropriate treatment of nonlinearities, simultaneous occurrence of contin

  7. The Gain Properties of 1-D Active Photonic Crystal

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The terminology 'ID frequency'(w ID) is proposed after analyzing the 1D active photonic crystal based on the transfer matrix method. The relationship between wID and the structure parameters of the photonic crystal is investigated.

  8. Modelling of Active Semiconductor Photonic Crystal Waveguides and Robust Designs based on Topology Optimization

    DEFF Research Database (Denmark)

    Chen, Yaohui; Wang, Fengwen; Ek, Sara;

    2011-01-01

    In this paper, we present a theoretical analysis of slow-light enhanced light amplification in an active semiconductor photonic crystal line defect waveguide. The impact of enhanced light-matter interactions on propagation effects and local carrier dynamics are investigated in the framework...... of the Lorentz reciprocity theorem. We highlight topology optimization as a systematic and robust design methodology considering manufacturing imperfections in optimizing active photonic crystal device performances, and compare the performance of standard photonic crystal waveguides with optimized structures....

  9. Advanced active quenching circuits for single-photon avalanche photodiodes

    Science.gov (United States)

    Stipčević, M.; Christensen, B. G.; Kwiat, P. G.; Gauthier, D. J.

    2016-05-01

    Commercial photon-counting modules, often based on actively quenched solid-state avalanche photodiode sensors, are used in wide variety of applications. Manufacturers characterize their detectors by specifying a small set of parameters, such as detection efficiency, dead time, dark counts rate, afterpulsing probability and single photon arrival time resolution (jitter), however they usually do not specify the conditions under which these parameters are constant or present a sufficient description. In this work, we present an in-depth analysis of the active quenching process and identify intrinsic limitations and engineering challenges. Based on that, we investigate the range of validity of the typical parameters used by two commercial detectors. We identify an additional set of imperfections that must be specified in order to sufficiently characterize the behavior of single-photon counting detectors in realistic applications. The additional imperfections include rate-dependence of the dead time, jitter, detection delay shift, and "twilighting." Also, the temporal distribution of afterpulsing and various artifacts of the electronics are important. We find that these additional non-ideal behaviors can lead to unexpected effects or strong deterioration of the system's performance. Specifically, we discuss implications of these new findings in a few applications in which single-photon detectors play a major role: the security of a quantum cryptographic protocol, the quality of single-photon-based random number generators and a few other applications. Finally, we describe an example of an optimized avalanche quenching circuit for a high-rate quantum key distribution system based on time-bin entangled photons.

  10. Workshop on photon activation therapy: proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Fairchild, R.G. (ed.)

    1985-04-18

    This Workshop was held concurrently with an IAEA Research Coordination Meeting on Exploration of the Possibility of High-LET Radiation for Non-conventional Radiotherapy in Cancer. The Workshop on Photon Activation Therapy (PAT) was given as a special session on April 18, as it was thoght PAT might eventually be found to be attractive to developing countries, which is a major concern of the IAEA. An effort was made to bring together representatives of the various groups known to be actively working on PAT; these included investigators from Sweden and Japan as well as the US. It is hoped that this compendium of papers will be of use to those currently active in this developing field, as well as to those who might join this area of endeavor in the future.

  11. Actively doped solid core Photonic Bandgap Fiber

    DEFF Research Database (Denmark)

    Broeng, Jes; Olausson, Christina Bjarnal Thulin; Lyngsøe, Jens Kristian;

    2010-01-01

    Solid photonic bandgap fibers offer distributed spectral filtering with extraordinary high suppression. This opens new possibilities of artificially tailoring the gain spectrum of fibers. We present record-performance of such fibers and outline their future applications....

  12. Monolithically Integrated Ge-on-Si Active Photonics

    Directory of Open Access Journals (Sweden)

    Jifeng Liu

    2014-07-01

    Full Text Available Monolithically integrated, active photonic devices on Si are key components in Si-based large-scale electronic-photonic integration for future generations of high-performance, low-power computation and communication systems. Ge has become an interesting candidate for active photonic devices in Si photonics due to its pseudo-direct gap behavior and compatibility with Si complementary metal oxide semiconductor (CMOS processing. In this paper, we present a review of the recent progress in Ge-on-Si active photonics materials and devices for photon detection, modulation, and generation. We first discuss the band engineering of Ge using tensile strain, n-type doping, Sn alloying, and separate confinement of Γ vs. L electrons in quantum well (QW structures to transform the material towards a direct band gap semiconductor for enhancing optoelectronic properties. We then give a brief overview of epitaxial Ge-on-Si materials growth, followed by a summary of recent investigations towards low-temperature, direct growth of high crystallinity Ge and GeSn alloys on dielectric layers for 3D photonic integration. Finally, we review the most recent studies on waveguide-integrated Ge-on-Si photodetectors (PDs, electroabsorption modulators (EAMs, and laser diodes (LDs, and suggest possible future research directions for large-scale monolithic electronic-photonic integrated circuits on a Si platform.

  13. Strain-optic active control for quantum integrated photonics

    CERN Document Server

    Humphreys, Peter C; Spring, Justin B; Moore, Merritt; Salter, Patrick S; Booth, Martin J; Kolthammer, W Steven; Walmsley, Ian A

    2014-01-01

    We present a practical method for active phase control on a photonic chip that has immediate applications in quantum photonics. Our approach uses strain-optic modification of the refractive index of individual waveguides, effected by a millimeter-scale mechanical actuator. The resulting phase change of propagating optical fields is rapid and polarization-dependent, enabling quantum applications that require active control and polarization encoding. We demonstrate strain-optic control of non-classical states of light in silica, showing the generation of 2-photon polarisation N00N states by manipulating Hong-Ou-Mandel interference. We also demonstrate switching times of a few microseconds, which are sufficient for silica-based feed-forward control of photonic quantum states.

  14. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    This book covers modern photonics accessibly and discusses the basic physical principles underlying all the applications and technology of photonicsThis volume covers the basic physical principles underlying the technology and all applications of photonics from statistical optics to quantum optics. The topics discussed in this volume are: Photons in perspective; Coherence and Statistical Optics; Complex Light and Singular Optics; Electrodynamics of Dielectric Media; Fast and slow Light; Holography; Multiphoton Processes; Optical Angular Momentum; Optical Forces, Trapping and Manipulation; Pol

  15. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying Biomedical Photonics, spectroscopy and microscopy This volume discusses biomedical photonics, spectroscopy and microscopy, the basic physical principles underlying the technology and its applications. The topics discussed in this volume are: Biophotonics; Fluorescence and Phosphorescence; Medical Photonics; Microscopy; Nonlinear Optics; Ophthalmic Technology; Optical Tomography; Optofluidics; Photodynamic Therapy; Image Processing; Imaging Systems; Sensors; Single Molecule Detection; Futurology in Photonics. Comprehensive and accessible cov

  16. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying the technology instrumentation of photonics This volume discusses photonics technology and instrumentation. The topics discussed in this volume are: Communication Networks; Data Buffers; Defense and Security Applications; Detectors; Fiber Optics and Amplifiers; Green Photonics; Instrumentation and Metrology; Interferometers; Light-Harvesting Materials; Logic Devices; Optical Communications; Remote Sensing; Solar Energy; Solid-State Lighting; Wavelength Conversion Comprehensive and accessible coverage of the whole of modern photonics Emphas

  17. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying thescience and technology of nanophotonics, its materials andstructures This volume presents nanophotonic structures and Materials.Nanophotonics is photonic science and technology that utilizeslight/matter interactions on the nanoscale where researchers arediscovering new phenomena and developing techniques that go wellbeyond what is possible with conventional photonics andelectronics.The topics discussed in this volume are: CavityPhotonics; Cold Atoms and Bose-Einstein Condensates; Displays;E-paper; Graphene; Integrated Photonics; Liquid Cry

  18. Q value analysis of microwave photonic filters

    Institute of Scientific and Technical Information of China (English)

    Lina ZHOU; Xinliang ZHANG; Enming XU

    2009-01-01

    This paper first presents the fundamental principles of the microwave photonic filters.As an example to explain how to implement a microwave photonic filter, a specific finite impulse response (FIR) filter is illustrated.Next, the Q value of the microwave photonic filters is analyzed theoretically, and methods around how to gain high Q value are discussed.Then,divided into FIR filter, first-order infinite impulse response (IIR) filter, and multi-order IIR filter, several novel microwave photonic filters with high Q value are listed and compared.The technical difficulties to get high Q value in first-order IIR filter and multi-order IIR filter are analyzed concretely.Finally, in order to gain higher Q value, a multi-order IIR microwave photonic filter that easily extends its order is presented and discussed.

  19. Modeling of gain saturation effects in active semiconductor photonic crystal waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2012-01-01

    In this paper, we present a theoretical analysis of slow-light enhanced light amplification in an active semiconductor photonic crystal line defect waveguide. The impact of enhanced light-matter interactions on carrier-depletion-induced modal gain saturation is investigated.......In this paper, we present a theoretical analysis of slow-light enhanced light amplification in an active semiconductor photonic crystal line defect waveguide. The impact of enhanced light-matter interactions on carrier-depletion-induced modal gain saturation is investigated....

  20. PHENIX Low Momentum Direct Photon Analysis

    Science.gov (United States)

    Fan, Wenqing; Phenix Collaboration

    2016-09-01

    The PHENIX experiment operates with one of the major detectors at the RHIC collider. One of the major goals of PHENIX is to identify and study Quark Gluon Plasma (QGP). Direct photons turn out to be an excellent probe due to their small interaction cross section with the collision produced medium hence carrying information of its properties from the space-time production points. In the PHENIX direct photon measurement, a large excess of low-pT photons in Au+Au collisions at 200 GeV is discovered compared to reference p+p collisions, which has been interpreted as thermal radiation from the QGP and hadron-gas (HG) medium. At the same time the excess photons have a large azimuthal anisotropy, expressed as Fourier coefficients v2 and v3. Measurements at a lower collision energy may provide new insight on the origin of the low-pT direct photons. In the experiment the current effort is to reduce the experimental uncertainties in Au+Au and p+p collisions via the photons' external conversion to di-electron pairs, and measure the direct photon yield in Cu+Au and p+Au collisions at 200 GeV as well as the yield in Au+Au collisions at lower 39 GeV and 62.4 GeV. We will present the improvements and the status of the ongoing analyses.

  1. Cascaded systems analysis of photon counting detectors

    Energy Technology Data Exchange (ETDEWEB)

    Xu, J.; Zbijewski, W.; Gang, G.; Stayman, J. W. [Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205 (United States); Taguchi, K.; Carrino, J. A. [Russell H. Morgan Department of Radiology, Johns Hopkins University, Baltimore, Maryland 21205 (United States); Lundqvist, M.; Fredenberg, E. [Philips Healthcare, Solna 171 41 (Sweden); Siewerdsen, J. H., E-mail: jeff.siewerdsen@jhu.edu [Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205 (United States); Russell H. Morgan Department of Radiology, Johns Hopkins University, Baltimore, Maryland 21205 (United States)

    2014-10-15

    Purpose: Photon counting detectors (PCDs) are an emerging technology with applications in spectral and low-dose radiographic and tomographic imaging. This paper develops an analytical model of PCD imaging performance, including the system gain, modulation transfer function (MTF), noise-power spectrum (NPS), and detective quantum efficiency (DQE). Methods: A cascaded systems analysis model describing the propagation of quanta through the imaging chain was developed. The model was validated in comparison to the physical performance of a silicon-strip PCD implemented on an experimental imaging bench. The signal response, MTF, and NPS were measured and compared to theory as a function of exposure conditions (70 kVp, 1–7 mA), detector threshold, and readout mode (i.e., the option for coincidence detection). The model sheds new light on the dependence of spatial resolution, charge sharing, and additive noise effects on threshold selection and was used to investigate the factors governing PCD performance, including the fundamental advantages and limitations of PCDs in comparison to energy-integrating detectors (EIDs) in the linear regime for which pulse pileup can be ignored. Results: The detector exhibited highly linear mean signal response across the system operating range and agreed well with theoretical prediction, as did the system MTF and NPS. The DQE analyzed as a function of kilovolt (peak), exposure, detector threshold, and readout mode revealed important considerations for system optimization. The model also demonstrated the important implications of false counts from both additive electronic noise and charge sharing and highlighted the system design and operational parameters that most affect detector performance in the presence of such factors: for example, increasing the detector threshold from 0 to 100 (arbitrary units of pulse height threshold roughly equivalent to 0.5 and 6 keV energy threshold, respectively), increased the f{sub 50} (spatial

  2. Slow-light enhanced gain in active photonic crystal waveguides

    CERN Document Server

    Ek, Sara; Chen, Yaohui; Semenova, Elizaveta; Yvind, Kresten; Mørk, Jesper

    2014-01-01

    Slow light is a fascinating physical effect, raising fundamental questions related to our understanding of light-matter interactions as well as offering new possibilities for photonic devices. From the first demonstrations of slow light propagation in ultra-cold atomic gasses, solid-state Ruby and photonic crystal structures, focus has shifted to applications, with slow light offering the ability to enhance and control light-matter interactions. The demonstration of tuneable delay lines, enhanced nonlinearities and spontaneous emission, enlarged spectral sensitivity and increased phase shifts illustrate the possibilities enabled by slow light propagation, with microwave photonics emerging as one of the promising applications. Here, we demonstrate that slow light can be used to control and increase the gain coefficient of an active semiconductor waveguide. The effect was theoretically predicted but not yet experimentally demonstrated. These results show a route towards realizing ultra-compact optical amplifier...

  3. Fabrication and Analysis of Photonic Crystals

    Science.gov (United States)

    Campbell, Dean J.; Korte, Kylee E.; Xia, Younan

    2007-01-01

    These laboratory experiments are designed to explore aspects of nanoscale chemistry by constructing and spectroscopically analyzing thin films of photonic crystals. Films comprised of colloidal spheres and polydimethylsiloxane exhibit diffraction-based stop bands that shift reversibly upon exposure to some common solvents. Topics covered in these…

  4. Analysis of photon-mediated entanglement between distinguishable matter qubits

    CERN Document Server

    Dyckovsky, A M

    2012-01-01

    We theoretically evaluate establishing remote entanglement between distinguishable matter qubits through interference and detection of two emitted photons. The fidelity of the entanglement operation is analyzed as a function of the temporal and frequency mode-matching between the photons emitted from each quantum memory. With a general analysis, we define limits on the absolute magnitudes of temporal and frequency mode-mismatches in order to maintain entanglement fidelities greater than 99% with two-photon detection efficiencies greater than 90%. We apply our analysis to several selected systems of quantum memories. Results indicate that high fidelities may be achieved in each system using current experimental techniques, while maintaining acceptable rates of entanglement. Thus, it might be possible to use two-photon-mediated entanglement operations between distinguishable quantum memories to establish a network for quantum communication and distributed quantum computation.

  5. Photonic network R and D activities in Japan

    Science.gov (United States)

    Kitayama, Ken-ichi; Miki, Tetsuya; Morioka, Toshio; Tsushima, Hideaki; Koga, Masafumi; Mori, Kazuyuki; Araki, Soichiro; Sato, Ken-ichi; Onaka, Hiroshi; Namiki, Shu; Aovama, Tomonori

    2005-11-01

    R and D activities on photonic networks in Japan are presented. First, milestones in current, ongoing R and D programs supported by Japanese government agencies are introduced, including long-distance and WDM fiber transmission, wavelength routing, optical burst switching, and control plane technology for IP backbone networks. Their goal was set to evolve a legacy telecommunications network to IP over WDM networks by introducing technologies for WDM and wavelength routing. We then discuss the perspectives of so-called PHASE II R and D programs for photonic networks over the next five years until 2010, by focusing on the report which has been recently issued by the Photonic Internet Forum (PIF), a consortium that has major carriers, telecom vendors, and Japanese academics as members. The PHASE II R and D programs should serve to establish a photonic platform to provide abundant bandwidth on demand, at any time on a real-time basis through the customer's initiative, to promote bandwidth-rich applications, such as grid computing, real-time digital-cinema streaming, medical and educational applications, and network storage in e-commerce.

  6. Theory of carrier depletion and light amplification in active slow light photonic crystal waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2013-01-01

    Using a perturbative approach, we perform a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguide. The impact of slow-light propagation on the carrier-depletion-induced nonlinear gain saturation...... of the device is investigated. An effective rate-equation-based model is presented. It is shown that it well accounts for the three-dimensional simulation results. Simulations indicate that a slow-light-enhanced photonic crystal traveling-wave amplifier has a high small-signal modal gain and low saturation...

  7. The analysis of the integral gated mode single photon detector

    Institute of Scientific and Technical Information of China (English)

    Wei Zheng-Jun; Li Kai-Zhen; Zhou Peng; Wang Jin-Dong; Liao Chang-Jun; Guo Jian-Ping; Liang Rui-Sheng; Liu Song-Hao

    2008-01-01

    This paper critically analyses and simulates the circuit configuration of the integral gated mode single photon detector which is proposed for eliminating the transient spikes problem of conventional gated mode single photon detector.The relationship between the values of the circuit elements and the effect of transient spikes cancellation has been obtained.With particular emphasis,the bias voltage of the avalanche photodiode and the output signal voltage of the integrator have been calculated.The obtained analysis results indicate that the output signal voltage of the integrator only relates to the total quantity of electricity of the avalanche charges by choosing the correct values of the circuit elements and integral time interval.These results can be used to optimize the performance of single photon detectors and provide guides for the design of single photon detectors.

  8. Category theoretic analysis of single-photon decision maker

    CERN Document Server

    Kim, Makoto Naruse Song-Ju; Berthel, Martin; Drezet, Aurélien; Huant, Serge; Hori, Hirokazu

    2016-01-01

    Decision making is a vital function in the era of artificial intelligence; however, its physical realizations and their theoretical fundamentals are not yet known. In our former study [Sci. Rep. 5, 513253 (2015)], we demonstrated that single photons can be used to make decisions in uncertain, dynamically changing environments. The multi-armed bandit problem was successfully solved using the dual probabilistic and particle attributes of single photons. Herein, we present the category theoretic foundation of the single-photon-based decision making, including quantitative analysis that agrees well with the experimental results. The category theoretic model unveils complex interdependencies of the entities of the subject matter in the most simplified manner, including a dynamically changing environment. In particular, the octahedral structure in triangulated categories provides a clear understanding of the underlying mechanisms of the single-photon decision maker. This is the first demonstration of a category the...

  9. Active Photonic crystal fibers for high power applications

    DEFF Research Database (Denmark)

    Olausson, Christina Bjarnal Thulin

    . This plays an important role in high power lasers and ampliers with respect to efficiency, packaging, and thermal handling. The third part of the work has involved developing tools for characterizing the mode quality and stability of large core bers. Stable, single-mode bers with larger cores are essential......The photonic crystal ber technology provides means to realize bers optimized for high power operation, due to the large single-mode cores and the unique design exibility of the microstructure. The work presented in this thesis focuses on improving the properties of active photonic crystal bers...... for high power ber lasers and ampliers, and on adding new functionality to the fibers - all with the purpose of pushing the technology towards high powers. The first part of the work has been to investigate photo darkening, the mitigation of which is crucial in the quest for higher powers. The work has...

  10. Analysis of photonic crystal fiber sensor character

    Institute of Scientific and Technical Information of China (English)

    GUO Xuan; LIU Feng; BI Wei-hong

    2007-01-01

    The special character of a PCF which is used as a gas or liquid sensor is discussed. The field distribution is analyzed when the solid core PCF is injected with different medium that has different relative dielectric constant (or refractive index). And the experiential formulas of the relation between refractive index of some kinds of liquid and their concentration are given,in order to measure the concentration of the relative liquid. At the same time, the effect of propagation constant on PCF sensor character is also discussed. Furthermore, the photonic band-gap (PBG) ofPCF (PBG-PCF) is calculated at different medium relative dielectric constant, when it is injected with different medium. That is the principle basis for this kind of PCF sensors.

  11. High-resolution photonic analysis with scanned probes

    Science.gov (United States)

    Wig, Andrew Gustaf

    Absorption spectroscopy is demonstrated to be feasible using a photon scanning tunneling microscope (PSTM) combined with a spectroscope. Methods of improving the spatial resolution and spectroscopic capabilities are studied in order to determine their potential practicability. Analysis of the photon scanning tunneling microscope (PSTM) and modifications made to the microscope are included with experimental results demonstrating certain image and spectral resolution capabilities. Results showing both the PSTM absorption spectra of gold island films and their independently acquired PSTM images are presented. An alternative scanning probe method involving photons is additionally examined. The new method is demonstrated to require specific improvements in order that it might provide a distinct improvement in resolution. The new type of scanning probe microscope is one utilizing nonlinear photonics: the nonlinear scanning tunneling microscope (NSTM). Basic results are described and two-photon fluorescence measurements are presented to demonstrate the principle of operation. In any scanned probe microscope or spectroscope, resolution is strongly dependent upon the characteristics of the signal as a function of distance to the sample and knowledge of these characteristics. The NSTM functionality is most dependent upon the sample-probe gap, but the gap also determines resolution in the PSTM. Hence measurements and calculations showing an analysis of the characteristics of the separation between the probe and sample surface are also presented.

  12. Time-Dependent Neutron and Photon Dose-Field Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wooten, Hasani Omar [Georgia Inst. of Technology, Atlanta, GA (United States)

    2005-08-01

    A unique tool is developed that allows the user to model physical representations of complicated glovebox facilities in two dimensions and determine neutral-particle flux and ambient dose-equivalent fields throughout that geometry. The Pandemonium code, originally designed to determine flux and dose-rates only, is improved to include realistic glovebox geometries, time-dependent source and detector positions, time-dependent shielding thickness calculations, time-integrated doses, a representative criticality accident scenario based on time-dependent reactor kinetics, and more rigorous photon treatment. A primary benefit of this work has been an extensive analysis and improvement of the photon model that is not limited to the application described in this thesis. The photon model has been extended in energy range to 10 MeV to include photons from fission and new photon buildup factors have been included that account for the effects of photon buildup at slant-path thicknesses as a function of angle, where the mean free path thickness has been preserved. The overall system of codes is user-friendly and it is directly applicable to facilities such as the plutonium facility at Los Alamos National Laboratory, where high-intensity neutron and photon emitters are regularly used. The codes may be used to determine a priori doses for given work scenarios in an effort to supply dose information to process models which will in turn assist decision makers on ensuring as low as reasonably achievable (ALARA) compliance. In addition, coupling the computational results of these tools with the process model visualization tools will help to increase worker safety and radiological safety awareness.

  13. Systematic approach for tolerance analysis of photonic systems

    NARCIS (Netherlands)

    Van Gurp, J.F.C.; Tichem, M.; Staufer, U.

    2011-01-01

    Passive alignment of photonic components is an assembly method compatible with a high production volume. Its precision performance relies completely on the dimensional accuracies of geometrical alignment features. A tolerance analysis plays a key role in designing and optimizing these passive alignm

  14. Several Organic Salts with High Two-Photon Active

    Institute of Scientific and Technical Information of China (English)

    TIAN, Yu-Peng; JIANG, Min-Hua; WANG, He-Zhou; FANG, Qi

    2001-01-01

    Several organic salts with D-A molecular structure and different counterion have been prepared and experimentally investigated. The two-photon induced frequency-upconverted spectra and two-photon pumped lasing are measured for the organic salt solutions in various solvents. The results indicate that counterions have influence on their stability and lasing property.

  15. A Few Photons Among Many: Unmixing Signal and Noise for Photon-Efficient Active Imaging

    CERN Document Server

    Rapp, Joshua

    2016-01-01

    Conventional LIDAR systems require hundreds or thousands of photon detections to form accurate depth and reflectivity images. Recent photon-efficient computational imaging methods are remarkably effective with only 1.0 to 3.0 detected photons per pixel, but they are not demonstrated at signal-to-background ratio (SBR) below 1.0 because their imaging accuracies degrade significantly in the presence of high background noise. We introduce a new approach to depth and reflectivity estimation that focuses on unmixing contributions from signal and noise sources. At each pixel in an image, short-duration range gates are adaptively determined and applied to remove detections likely to be due to noise. For pixels with too few detections to perform this censoring accurately, we borrow data from neighboring pixels to improve depth estimates, where the neighborhood formation is also adaptive to scene content. Algorithm performance is demonstrated on experimental data at varying levels of noise. Results show improved perfo...

  16. Analysis on optical bistability parameters in photonic switching devices

    Science.gov (United States)

    Sarafraz, Hossein; Sayeh, Mohammad R.

    2016-06-01

    An investigation has been done on the parameters of a hysteretic bistable optical Schmitt trigger device. From a design point of view, it is important to know the regions where this bistability occurs and is fully functional with respect to its subsystem parameters. Otherwise experimentally reaching such behavior will be very time-consuming and frustrating, especially with multiple devices employed in a single photonic circuit. A photonic Schmitt trigger consisting of two feedbacked inverting amplifiers, each characterized by -m (slope), A (y-intercept), and B (constant base) parameters is considered. This system is investigated dynamically with a varying input to find its stable and unstable states both mathematically and with simulation. In addition to a complete mathematical analysis of the system, we also describe how m, A, and B can be properly chosen in order to satisfy certain system conditions that result in bistability. More restrictions are also imposed to these absolute conditions by the system conditions as will be discussed. Finally, all results are verified in a more realistic photonic simulation.

  17. Terahertz Active Photonic Crystals for Condensed Gas Sensing

    Directory of Open Access Journals (Sweden)

    Karl Unterrainer

    2011-06-01

    Full Text Available The terahertz (THz spectral region, covering frequencies from 1 to 10 THz, is highly interesting for chemical sensing. The energy of rotational and vibrational transitions of molecules lies within this frequency range. Therefore, chemical fingerprints can be derived, allowing for a simple detection scheme. Here, we present an optical sensor based on active photonic crystals (PhCs, i.e., the pillars are fabricated directly from an active THz quantum-cascade laser medium. The individual pillars are pumped electrically leading to laser emission at cryogenic temperatures. There is no need to couple light into the resonant structure because the PhC itself is used as the light source. An injected gas changes the resonance condition of the PhC and thereby the laser emission frequency. We achieve an experimental frequency shift of 10−3 times the center lasing frequency. The minimum detectable refractive index change is 1.6 × 10−5 RIU.

  18. Photonic activation of plasminogen induced by low dose UVB.

    Directory of Open Access Journals (Sweden)

    Manuel Correia

    Full Text Available Activation of plasminogen to its active form plasmin is essential for several key mechanisms, including the dissolution of blood clots. Activation occurs naturally via enzymatic proteolysis. We report that activation can be achieved with 280 nm light. A 2.6 fold increase in proteolytic activity was observed after 10 min illumination of human plasminogen. Irradiance levels used are in the same order of magnitude of the UVB solar irradiance. Activation is correlated with light induced disruption of disulphide bridges upon UVB excitation of the aromatic residues and with the formation of photochemical products, e.g. dityrosine and N-formylkynurenine. Most of the protein fold is maintained after 10 min illumination since no major changes are observed in the near-UV CD spectrum. Far-UV CD shows loss of secondary structure after illumination (33.4% signal loss at 206 nm. Thermal unfolding CD studies show that plasminogen retains a native like cooperative transition at ~70 ºC after UV-illumination. We propose that UVB activation of plasminogen occurs upon photo-cleavage of a functional allosteric disulphide bond, Cys737-Cys765, located in the catalytic domain and in van der Waals contact with Trp761 (4.3 Å. Such proximity makes its disruption very likely, which may occur upon electron transfer from excited Trp761. Reduction of Cys737-Cys765 will result in likely conformational changes in the catalytic site. Molecular dynamics simulations reveal that reduction of Cys737-Cys765 in plasminogen leads to an increase of the fluctuations of loop 760-765, the S1-entrance frame located close to the active site. These fluctuations affect the range of solvent exposure of the catalytic triad, particularly of Asp646 and Ser74, which acquire an exposure profile similar to the values in plasmin. The presented photonic mechanism of plasminogen activation has the potential to be used in clinical applications, possibly together with other enzymatic treatments for the

  19. Analysis of Photonic Quantum Nodes Based on Deterministic Single-Photon Raman Passage

    CERN Document Server

    Rosenblum, Serge

    2014-01-01

    The long-standing goal of deterministically controlling a single photon using another was recently realized in various experimental settings. Among these, a particularly attractive demonstration relied on deterministic single-photon Raman passage in a three-level Lambda system coupled to a single-mode waveguide. Beyond the ability to control the direction of propagation of one photon by the direction of another photon, this scheme can also perform as a passive quantum memory and a universal quantum gate. Relying on interference, this all-optical, coherent scheme requires no additional control fields, and can therefore form the basis for scalable quantum networks composed of passive quantum nodes that interact with each other only with single photon pulses. Here we present an analytical and numerical study of deterministic single-photon Raman passage, and characterise its limitations and the parameters for optimal operation. Specifically, we study the effect of losses and the presence of multiple excited state...

  20. Two-photon imaging and analysis of neural network dynamics

    Science.gov (United States)

    Lütcke, Henry; Helmchen, Fritjof

    2011-08-01

    The glow of a starry night sky, the smell of a freshly brewed cup of coffee or the sound of ocean waves breaking on the beach are representations of the physical world that have been created by the dynamic interactions of thousands of neurons in our brains. How the brain mediates perceptions, creates thoughts, stores memories and initiates actions remains one of the most profound puzzles in biology, if not all of science. A key to a mechanistic understanding of how the nervous system works is the ability to measure and analyze the dynamics of neuronal networks in the living organism in the context of sensory stimulation and behavior. Dynamic brain properties have been fairly well characterized on the microscopic level of individual neurons and on the macroscopic level of whole brain areas largely with the help of various electrophysiological techniques. However, our understanding of the mesoscopic level comprising local populations of hundreds to thousands of neurons (so-called 'microcircuits') remains comparably poor. Predominantly, this has been due to the technical difficulties involved in recording from large networks of neurons with single-cell spatial resolution and near-millisecond temporal resolution in the brain of living animals. In recent years, two-photon microscopy has emerged as a technique which meets many of these requirements and thus has become the method of choice for the interrogation of local neural circuits. Here, we review the state-of-research in the field of two-photon imaging of neuronal populations, covering the topics of microscope technology, suitable fluorescent indicator dyes, staining techniques, and in particular analysis techniques for extracting relevant information from the fluorescence data. We expect that functional analysis of neural networks using two-photon imaging will help to decipher fundamental operational principles of neural microcircuits.

  1. Two-photon imaging and analysis of neural network dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Luetcke, Henry; Helmchen, Fritjof [Brain Research Institute, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich (Switzerland)

    2011-08-15

    The glow of a starry night sky, the smell of a freshly brewed cup of coffee or the sound of ocean waves breaking on the beach are representations of the physical world that have been created by the dynamic interactions of thousands of neurons in our brains. How the brain mediates perceptions, creates thoughts, stores memories and initiates actions remains one of the most profound puzzles in biology, if not all of science. A key to a mechanistic understanding of how the nervous system works is the ability to measure and analyze the dynamics of neuronal networks in the living organism in the context of sensory stimulation and behavior. Dynamic brain properties have been fairly well characterized on the microscopic level of individual neurons and on the macroscopic level of whole brain areas largely with the help of various electrophysiological techniques. However, our understanding of the mesoscopic level comprising local populations of hundreds to thousands of neurons (so-called 'microcircuits') remains comparably poor. Predominantly, this has been due to the technical difficulties involved in recording from large networks of neurons with single-cell spatial resolution and near-millisecond temporal resolution in the brain of living animals. In recent years, two-photon microscopy has emerged as a technique which meets many of these requirements and thus has become the method of choice for the interrogation of local neural circuits. Here, we review the state-of-research in the field of two-photon imaging of neuronal populations, covering the topics of microscope technology, suitable fluorescent indicator dyes, staining techniques, and in particular analysis techniques for extracting relevant information from the fluorescence data. We expect that functional analysis of neural networks using two-photon imaging will help to decipher fundamental operational principles of neural microcircuits.

  2. Photon-deficient bone scan lesion as a precursor of active Paget's disease

    Energy Technology Data Exchange (ETDEWEB)

    Jaspers, M.M.J.R.; Pauwels, E.K.J.; Blom, J. (Department of Diagnostic Radiology, Division of Nuclear Medicine, University Hospital Leiden (Netherlands)); Harinck, H.I.J. (Clinical Investigation Unit, Department of Endocrinology, University Hospital Leiden, Netherands)

    1984-05-15

    A case is presented in which a Pagetoid lesion was demonstrated as a photon-deficient area (cold spot) on the bone scan. This area changed into a hot spot 3 years after its discovery. Clinical and radiological observations provide evidence that a scintigraphically photon-deficient area may represent a precursor of active Paget's disease.

  3. Photonic Network R&D Activities in Japan-Current Activities and Future Perspectives

    Science.gov (United States)

    Kitayama, Ken-Ichi; Miki, Tetsuya; Morioka, Toshio; Tsushima, Hideaki; Koga, Masafumi; Mori, Kazuyuki; Araki, Soichiro; Sato, Ken-Ichi; Onaka, Hiroshi; Namiki, Shu; Aoyama, Tomonori

    2005-10-01

    R&D activities on photonic networks in Japan are presented. First, milestones in current ongoing R&D programs supported by Japanese government agencies are introduced, including long-distance and wavelength division multiplexing (WDM) fiber transmission, wavelength routing, optical burst switching (OBS), and control-plane technology for IP backbone networks. Their goal was set to evolve a legacy telecommunications network to IP-over-WDM networks by introducing technologies for WDM and wavelength routing. We then discuss the perspectives of so-called PHASE II R&D programs for photonic networks over the next 5 years until 2010, by focusing on the report that has been recently issued by the Photonic Internet Forum (PIF), a consortium that has major carriers, telecom vendors, and Japanese academics as members. The PHASE II R&D programs should serve to establish a photonic platform to provide abundant bandwidth on demand, at any time on a real-time basis, through the customer's initiative to promote bandwidth-rich applications, such as grid computing, real-time digital-cinema streaming, medical and educational applications, and network storage in e-commerce.

  4. Photonic encryption : modeling and functional analysis of all optical logic.

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jason D.; Schroeppel, Richard Crabtree; Robertson, Perry J.

    2004-10-01

    With the build-out of large transport networks utilizing optical technologies, more and more capacity is being made available. Innovations in Dense Wave Division Multiplexing (DWDM) and the elimination of optical-electrical-optical conversions have brought on advances in communication speeds as we move into 10 Gigabit Ethernet and above. Of course, there is a need to encrypt data on these optical links as the data traverses public and private network backbones. Unfortunately, as the communications infrastructure becomes increasingly optical, advances in encryption (done electronically) have failed to keep up. This project examines the use of optical logic for implementing encryption in the photonic domain to achieve the requisite encryption rates. This paper documents the innovations and advances of work first detailed in 'Photonic Encryption using All Optical Logic,' [1]. A discussion of underlying concepts can be found in SAND2003-4474. In order to realize photonic encryption designs, technology developed for electrical logic circuits must be translated to the photonic regime. This paper examines S-SEED devices and how discrete logic elements can be interconnected and cascaded to form an optical circuit. Because there is no known software that can model these devices at a circuit level, the functionality of S-SEED devices in an optical circuit was modeled in PSpice. PSpice allows modeling of the macro characteristics of the devices in context of a logic element as opposed to device level computational modeling. By representing light intensity as voltage, 'black box' models are generated that accurately represent the intensity response and logic levels in both technologies. By modeling the behavior at the systems level, one can incorporate systems design tools and a simulation environment to aid in the overall functional design. Each black box model takes certain parameters (reflectance, intensity, input response), and models the optical ripple

  5. Active Photonic Crystal Switches: Modeling, Design and Experimental Characterization

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Yu, Yi; Kristensen, Philip Trøst;

    2013-01-01

    In this paper, we present recent progress in modeling, design, fabrication and experimental characterization of InP photonic crystal all-optical switches. Novel designs with increased flexibility and performance are presented, and their operation using high speed data signals is analyzed numerica......In this paper, we present recent progress in modeling, design, fabrication and experimental characterization of InP photonic crystal all-optical switches. Novel designs with increased flexibility and performance are presented, and their operation using high speed data signals is analyzed...

  6. Analysis and control of the photon beam position at PLS-II

    Energy Technology Data Exchange (ETDEWEB)

    Ko, J.; Kim, I.-Y.; Kim, C.; Kim, D.-T.; Huang, J.-Y.; Shin, S., E-mail: tlssh@postech.ac.kr [POSTECH, Pohang, Kyungbuk 790-784 (Korea, Republic of)

    2016-02-18

    The variation of the photon beam position in a beamline, which is a critical issue for user experiments, is analyzed and corrected through the correlation link with the electron beam position in the storage ring. At third-generation light sources, the photon beam position stability is a critical issue for user experiments. In general, photon beam position monitors are developed to detect the real photon beam position, and the position is controlled by a feedback system in order to maintain the reference photon beam position. At Pohang Light Source II, a photon beam position stability of less than 1 µm r.m.s. was achieved for a user service period in the beamline, where the photon beam position monitor is installed. Nevertheless, a detailed analysis of the photon beam position data was necessary in order to ensure the performance of the photon beam position monitor, since it can suffer from various unknown types of noise, such as background contamination due to upstream or downstream dipole radiation, and undulator gap dependence. This paper reports the results of a start-to-end study of the photon beam position stability and a singular value decomposition analysis to confirm the reliability of the photon beam position data.

  7. Active III-V Semiconductor Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Ek, Sara; Chen, Yaohui; Schubert, Martin;

    2011-01-01

    We experimentally demonstrate enhanced amplified spontaneous emission in a quantum well III-V semiconductor photonic crystal waveguide slab. The effect is described by enhanced light matter interaction with the decrease of the group velocity. These are promising results for future compact devices...... for terabit/s communication, such as miniaturised semiconductor optical amplifiers and mode-locked lasers....

  8. Slow-light-enhanced gain in active photonic crystal waveguides

    DEFF Research Database (Denmark)

    Ek, Sara; Hansen, Per Lunnemann; Chen, Yaohui

    2014-01-01

    crystal structural parameters, the maximum value of the gain coefficient can be increased compared with a ridge waveguide structure and at the same time the spectral position of the peak gain be controlled. The experimental results are in qualitative agreement with theory and show that gain values similar...... to those realized in state-of-the-art semiconductor optical amplifiers should be attainable in compact photonic integrated amplifiers...

  9. Single photon laser altimeter data processing, analysis and experimental validation

    Science.gov (United States)

    Vacek, Michael; Peca, Marek; Michalek, Vojtech; Prochazka, Ivan

    2015-10-01

    Spaceborne laser altimeters are common instruments on-board the rendezvous spacecraft. This manuscript deals with the altimeters using a single photon approach, which belongs to the family of time-of-flight range measurements. Moreover, the single photon receiver part of the altimeter may be utilized as an Earth-to-spacecraft link enabling one-way ranging, time transfer and data transfer. The single photon altimeters evaluate actual altitude through the repetitive detections of single photons of the reflected laser pulses. We propose the single photon altimeter signal processing and data mining algorithm based on the Poisson statistic filter (histogram method) and the modified Kalman filter, providing all common altimetry products (altitude, slope, background photon flux and albedo). The Kalman filter is extended for the background noise filtering, the varying slope adaptation and the non-causal extension for an abrupt slope change. Moreover, the algorithm partially removes the major drawback of a single photon altitude reading, namely that the photon detection measurement statistics must be gathered. The developed algorithm deduces the actual altitude on the basis of a single photon detection; thus, being optimal in the sense that each detected signal photon carrying altitude information is tracked and no altitude information is lost. The algorithm was tested on the simulated datasets and partially cross-probed with the experimental data collected using the developed single photon altimeter breadboard based on the microchip laser with the pulse energy on the order of microjoule and the repetition rate of several kilohertz. We demonstrated that such an altimeter configuration may be utilized for landing or hovering a small body (asteroid, comet).

  10. Bio-optofluidics and Bio-photonics: Programmable Phase Optics activities at DTU Fotonik

    DEFF Research Database (Denmark)

    Bañas, Andrew Rafael; Palima, Darwin; Pedersen, Finn

    We present ongoing research and development activities for constructing a compact next generation BioPhotonics Workstation and a Bio-optofluidic Cell Sorter (cell-BOCS) for all-optical micromanipulation platforms utilizing low numerical aperture beam geometries. Unlike conventional high NA optica...... the BioPhotonics Workstation platform more photon efficient by studying the 3D distribution of the counter propagating beams and utilizing the Generalized Phase Contrast (GPC) method for illuminating the applied spatial light modulators.......We present ongoing research and development activities for constructing a compact next generation BioPhotonics Workstation and a Bio-optofluidic Cell Sorter (cell-BOCS) for all-optical micromanipulation platforms utilizing low numerical aperture beam geometries. Unlike conventional high NA optical...

  11. Analysis of liquid crystal properties for photonic crystal fiber devices

    DEFF Research Database (Denmark)

    Weirich, Johannes; Lægsgaard, Jesper; Wei, Lei;

    2009-01-01

    We analyze the bandgap structure of Liquid Crystal infiltrated Photonic Crystal Fibers depending on the parameters of the Liquid Crystals by means of finite element simulations. For a biased Liquid Crystal Photonic Crystal Fiber, we show how the tunability of the bandgap position depends on the L...

  12. Photon budget analysis for fluorescence lifetime imaging microscopy

    NARCIS (Netherlands)

    Zhao, Q.; Young, I.T.; De Jong, J.G.S.

    2011-01-01

    We have constructed a mathematical model to analyze the photon efficiency of frequency-domain fluorescence lifetime imaging microscopy (FLIM). The power of the light source needed for illumination in a FLIM system and the signal-to-noise ratio of the detector have led us to a photon “budget.” These

  13. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

  14. Photonic Activation of Plasminogen induced by low dose UVB

    DEFF Research Database (Denmark)

    Correia, Manuel Guiherme L.P. Marins; Snabe, Torben; Thiagarajan, Viruthachalam;

    2015-01-01

    Activation of plasminogen to its active form plasmin is essential for several key mechanisms, including the dissolution of blood clots. Activation occurs naturally via enzymatic proteolysis. We report that activation can be achieved with 280 nm light. A 2.6 fold increase in proteolytic activity w...

  15. Maleimide activation of photon upconverting nanoparticles for bioconjugation

    Science.gov (United States)

    Liebherr, Raphaela B.; Soukka, Tero; Wolfbeis, Otto S.; Gorris, Hans H.

    2012-12-01

    Photon upconverting nanoparticles (UCNPs) have become an important new class of optical labels. Their unique property of emitting visible light after photo-excitation with near-infrared radiation enables biological imaging without background interference or cell damage. Biological applications require UCNPs that are dispersible in water and allow the attachment of biomolecules. Oleic acid-coated UCNPs obtained by solvothermal synthesis were functionalized with both hydrophilic PEG and thiol-reactive maleimides, either by ligand exchange or by silanization. Three different types of maleimide-functionalized UCNPs were prepared and characterized by transmission electron microscopy, dynamic light scattering and Raman spectroscopy. Ligand exchange of oleic acid by maleimide-PEG-COOH yielded UCNPs that did not aggregate, were colloidally stable and reacted readily with proteins. Such luminescent labels are required for background-free imaging and many other bioanalytical applications.

  16. Photon-activated charge domain in high-gain photoconductive switches

    Institute of Scientific and Technical Information of China (English)

    Wei Shi(施卫); Huiying Dai(戴慧莹); Xiaowei Sun(孙小卫)

    2003-01-01

    We report our experimental observation of charge domain oscillation in semi-insulating GaAs photoconductive semiconductor switches (PCSSs). The high-gain PCSS is intrinsically a photon-activated charge domain device. It is the photon-activated carriers that satisfy the requirement of charge domain formation on carrier concentration and device length product of 1012 cm-2. We also show that, because of the repeated process of domain formation, the domain travels with a compromised speed of electron saturation velocity and the speed of light. As a result, the transit time of charge domains in PCSS is much shorter than that of traditional Gunn domains.

  17. Photon and neutrino emission from active galactic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Biermann, Peter L. [MPI for Radioastronomy, Bonn (Germany); Becker, Julia K. [Inst. for Phys., Univ. Bochum, Bochum (Germany); Caramete, Laurentiu I. [MPI for Radioastronomy, Bonn (Germany); Fraschetti, Federico [Inst. for Phys., Univ. Bochum, Bochum (Germany); Kneiske, Tanja [Inst. fuer Exp.Physik, Univ. Hamburg, Hamburg (Germany); Meli, Athina [Erlangen Center for Astroparticle Physics, University Erlangen-Nuremberg (Germany); Stanev, Todor [Bartol Research Inst., Univ. of Delaware, Newark, DE (United States)

    2011-08-15

    Supermassive black holes in the centers of galaxies are very common. They are known to rotate, accrete, spin down and eject highly relativistic jets; those jets pointed at us all seem to show a spectrum with two strong bumps, one in the TeV photon range, and one in X-rays - ordered by the emission frequency of the first bump this constitutes the blazar sequence. Here we wish to explain this sequence as primary synchrotron emission of energetic electrons and protons, and secondary emission from interactions at the first strong shockwave pattern in the relativistic jet. With two key assumptions on particle scattering, this concept predicts that the two basic maximum peak frequencies {nu}{sub syn,e,p} scale with the mass of the central black hole as {nu}{sub e,p{approx}}M{sub BH}{sup -1/2}, of {nu}{sub syn,p}/{nu}{sub syn,e}=(m{sub p}/m{sub e}){sup 3}, and the luminosities with the mass itself L{sub e,p{approx}}M{sub BH}. Due to strong losses of the leptons, the peak luminosities are generally the same, but with large variations around equality. This model predicts large fluxes in ultra high energy cosmic rays, and also large neutrino luminosities.

  18. Experimental Observations of Nuclear Activity in Deuterated Materials Subjected to a Low-Energy Photon Beam

    Science.gov (United States)

    Steinetz, Bruce M.; Benyo, Theresa L.; Pines, Vladimir; Pines, Marianna; Forsley, Lawrence P.; Westmeyer, Paul A.; Chait, Arnon; Becks, Michael D.; Martin, Richard E.; Hendricks, Robert C.; Penney, Nicholas; Marsolais, Annette M.; Kamm, Tracy R.

    2017-01-01

    Exposure of highly deuterated materials to a low-energy (nom. 2 MeV) photon beam resulted in nuclear activity of both the parent metals of hafnium and erbium and a witness material (molybdenum) mixed with the reactants. Gamma spectral analysis of all deuterated materials, ErD2.8+C36D74+Mo and HfD2+C36D74+Mo, showed that nuclear processes had occurred as shown by unique gamma signatures. For the deuterated erbium specimens, posttest gamma spectra showed evidence of radioisotopes of erbium ((163)Er and (171)Er) and of molybdenum ((99)Mo and (101)Mo) and by beta decay, technetium (99mTc and 101Tc). For the deuterated hafnium specimens, posttest gamma spectra showed evidence of radioisotopes of hafnium (180mHf and 181Hf) and molybdenum ((99)Mo and (101)Mo), and by beta decay, technetium ((99m)Tc and (101)Tc). In contrast, when either the hydrogenated or non-gas-loaded erbium or hafnium materials were exposed to the gamma flux, the gamma spectra revealed no new isotopes. Neutron activation materials showed evidence of thermal and epithermal neutrons. CR-39 solid-state nuclear track detectors showed evidence of fast neutrons with energies between 1.4 and 2.5 MeV and several instances of triple tracks, indicating (is) greater than 10 MeV neutrons. Further study is required to determine the mechanism causing the nuclear activity.

  19. Study on optical gain of one-dimensional photonic crystals with active impurity

    Institute of Scientific and Technical Information of China (English)

    Zhenghua Li; Tinggen Shen; Xuehua Song; Junfeng Ma; Yong Sheng; Gang Wang

    2007-01-01

    Localized fields in the defect mode of one-dimensional photonic crystals with active impurity are studied with the help of the theory of spontaneous emission from two-level atoms embedded in photonic crystals.Numerical simulations demonstrate that the enhancement of stimulated radiation, as well as the phenomena of transmissivity larger than unity and the abnormality of group velocity close to the edges of photonic band gap, are related to the negative imaginary part of the complex effective refractive index of doped layers. This means that the complex effective refractive index has a negative imaginary part, and that the impurity state with very high quality factor and great state density will occur in the photonic forbidden band if active impurity is introduced into the defect layer properly. Therefore, the spontaneous emission can be enhanced, the amplitude of stimulated emission will be very large and it occurs most probably close to the edges of photonic band gap with the fundamental reason, the group velocity close to the edges of band gap is very small or abnormal.

  20. Calibration of Cherenkov detectors for monoenergetic photon imaging in active interrogation applications

    Science.gov (United States)

    Rose, P. B.; Erickson, A. S.

    2015-11-01

    Active interrogation of cargo containers using monoenergetic photons offers a rapid and low-dose approach to search for shielded special nuclear materials. Cherenkov detectors can be used for imaging of the cargo provided that gamma ray energies used in interrogation are well resolved, as the case in 11B(d,n-γ)12C reaction resulting in 4.4 MeV and 15.1 MeV photons. While an array of Cherenkov threshold detectors reduces low energy background from scatter while providing the ability of high contrast transmission imaging, thus confirming the presence of high-Z materials, these detectors require a special approach to energy calibration due to the lack of resolution. In this paper, we discuss the utility of Cherenkov detectors for active interrogation with monoenergetic photons as well as the results of computational and experimental studies of their energy calibration. The results of the studies with sources emitting monoenergetic photons as well as complex gamma ray spectrum sources, for example 232Th, show that calibration is possible as long as the energies of photons of interest are distinct.

  1. Thermal analysis of line-defect photonic crystal lasers

    DEFF Research Database (Denmark)

    Xue, Weiqi; Ottaviano, Luisa; Chen, Yaohui

    2015-01-01

    We report a systematic study of thermal effects in photonic crystal membrane lasers based on line-defect cavities. Two material platforms, InGaAsP and InP, are investigated experimentally and numerically. Lasers with quantum dot layers embedded in an InP membrane exhibit lasing at room temperatur...

  2. Analysis of photonic band-gap structures in stratified medium

    DEFF Research Database (Denmark)

    Tong, Ming-Sze; Yinchao, Chen; Lu, Yilong;

    2005-01-01

    Purpose - To demonstrate the flexibility and advantages of a non-uniform pseudo-spectral time domain (nu-PSTD) method through studies of the wave propagation characteristics on photonic band-gap (PBG) structures in stratified medium Design/methodology/approach - A nu-PSTD method is proposed...

  3. Liquid crystal parameter analysis for tunable photonic bandgap fiber devices

    DEFF Research Database (Denmark)

    Weirich, Johannes; Lægsgaard, Jesper; Wei, Lei;

    2010-01-01

    We investigate the tunability of splay-aligned liquid crystals for the use in solid core photonic crystal fibers. Finite element simulations are used to obtain the alignment of the liquid crystals subject to an external electric field. By means of the liquid crystal director field the optical per...

  4. Impact of slow-light enhancement on optical propagation in active semiconductor photonic crystal waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; de Lasson, Jakob Rosenkrantz; Gregersen, Niels;

    2015-01-01

    We derive and validate a set of coupled Bloch wave equations for analyzing the reflection and transmission properties of active semiconductor photonic crystal waveguides. In such devices, slow-light propagation can be used to enhance the material gain per unit length, enabling, for example...

  5. Slow-light enhancement of spontaneous emission in active photonic crystal waveguides

    DEFF Research Database (Denmark)

    Ek, Sara; Chen, Yaohui; Semenova, Elizaveta;

    2012-01-01

    Photonic crystal defect waveguides with embedded active layers containing single or multiple quantum wells or quantum dots have been fabricated. Spontaneous emission spectra are enhanced close to the bandedge, consistently with the enhancement of gain by slow light effects. These are promising...... results for future compact devices for terabit/s communication, such as miniaturised semiconductor optical amplifiers and mode-locked lasers....

  6. Quantum entanglement distribution with 810 nm photons through active telecommunication fibers

    CERN Document Server

    Holloway, Catherine; Erven, Chris; Jennewein, Thomas

    2011-01-01

    We demonstrate the distribution of polarization-entangled photons for the purpose of quantum key distribution (QKD) along active telecom fibers. Entangled photon pairs of 810 nm wavelength generated by a Sagnac interferometer source were coupled into standard telecom single mode fibers. The fibers were either dark or carrying a standardized 1550 nm ethernet signals (1000BASE-ZX) with a nominal speed of 1 GBps from regular media converter devices, without any requirements on the optical power or spectrum transmitted. Our system demonstrates a QKD network covering 6 km in distance with a central service provider for classical and quantum data.

  7. Two-Photon Activation of p-Hydroxyphenacyl Phototriggers: Toward Spatially Controlled Release of Diethyl Phosphate and ATP.

    Science.gov (United States)

    Houk, Amanda L; Givens, Richard S; Elles, Christopher G

    2016-03-31

    Two-photon activation of the p-hydroxyphenacyl (pHP) photoactivated protecting group is demonstrated for the first time using visible light at 550 nm from a pulsed laser. Broadband two-photon absorption measurements reveal a strong two-photon transition (>10 GM) near 4.5 eV that closely resembles the lowest-energy band at the same total excitation energy in the one-photon absorption spectrum of the pHP chromophore. The polarization dependence of the two-photon absorption band is consistent with excitation to the same S3 ((1)ππ*) excited state for both one- and two-photon activation. Monitoring the progress of the uncaging reaction under nonresonant excitation at 550 nm confirms a quadratic intensity dependence and that two-photon activation of the uncaging reaction is possible using visible light in the range 500-620 nm. Deprotonation of the pHP chromophore under mildly basic conditions shifts the absorption band to lower energy (3.8 eV) in both the one- and two-photon absorption spectra, suggesting that two-photon activation of the pHP chromophore may be possible using light in the range 550-720 nm. The results of these measurements open the possibility of spatially and temporally selective release of biologically active compounds from the pHP protecting group using visible light from a pulsed laser.

  8. Guidance in Kagome-like photonic crystal fibres I: analysis of an ideal fibre structure.

    Science.gov (United States)

    Chen, Lei; Pearce, Greg J; Birks, Timothy A; Bird, David M

    2011-03-28

    Propagation of light in a square-lattice hollow-core photonic crystal fibre is analysed as a model of guidance in a class of photonic crystal fibres that exhibit broad-band guidance without photonic bandgaps. A scalar governing equation is used and analytic solutions based on transfer matrices are developed for the full set of modes. It is found that an exponentially localised fundamental mode exists for a wide range of frequencies. These analytic solutions of an idealised structure will form the basis for analysis of guidance in a realistic structure in a following paper.

  9. Simultaneous two-photon activation of type-I photodynamic therapy agents.

    Science.gov (United States)

    Fisher, W G; Partridge, W P; Dees, C; Wachter, E A

    1997-08-01

    The excitation and emission properties of several psoralen derivatives are compared using conventional single-photon excitation and simultaneous two-photon excitation (TPE). Two-photon excitation is effected using the output of a mode-locked titanium: sapphire laser, the near infrared output of which is used to promote nonresonant TPE directly. Specifically, the excitation spectra and excited-state properties of 8-methoxypsoralen and 4'-aminomethyl-4,5,8-trimethylpsoralen are shown to be equivalent using both modes of excitation. Further, in vitro feasibility of two-photon photodynamic therapy (PDT) is demonstrated using Salmonella typhimurium. Two-photon excitation may be beneficial in the practice of PDT because it would allow replacement of visible or UV excitation light with highly penetrating, nondamaging near infrared light and could provide a means for improving localization of therapy. Comparison of possible laser excitation sources for PDT reveals the titanium: sapphire laser to be exceptionally well suited for nonlinear excitation of PDT agents in biological systems due to its extremely short pulse width and high repetition rate that together provide efficient PDT activation and greatly reduced potential for biological damage.

  10. Activation of snap-top capped mesoporous silica nanocontainers using two near-infrared photons.

    Science.gov (United States)

    Guardado-Alvarez, Tania M; Sudha Devi, Lekshmi; Russell, Melissa M; Schwartz, Benjamin J; Zink, Jeffrey I

    2013-09-25

    Photoactivation of "snap-top" stoppers over the pore openings of mesoporous silica nanoparticles releases intact cargo molecules from the pores. The on-command release can be stimulated by either one UV photon or two coherent near-IR photons. Two-photon activation is particularly desirable for use in biological systems because it enables good tissue penetration and precise spatial control. Stoppers were assembled by first binding photolabile coumarin-based molecules to the nanoparticle surface. Then, after the particles were loaded with cargo, bulky β-cyclodextrin (CD) molecules were noncovalently associated with the substituted coumarin molecule, blocking the pores and preventing the cargo from escaping. One-photon excitation at 376 nm or two-photon excitation at 800 nm cleaves the bond holding the coumarin to the nanopore, releasing both the CD cap and the cargo. The dynamics of both the cleavage of the cap and the cargo release was monitored using fluorescence spectroscopy. This system traps intact cargo molecules without the necessity of chemical modification, releases them with tissue-penetrating near-IR light, and has possible applications in photostimulated drug delivery.

  11. A universal setup for active control of a single-photon detector

    CERN Document Server

    Liu, Qin; Kurtsiefer, Christian; Skaar, Johannes; Makarov, Vadim; Gerhardt, Ilja

    2013-01-01

    The influence of bright light on a single-photon detector has been described in a number of recent publications. The impact, especially on quantum key distribution (QKD), is important, and a number of hacking experiments have been tailored to achieve a full control of single-photon detectors in a QKD setup. Special attention has been given to avoid introducing further errors into a QKD system. Here we describe the design and technical details of an apparatus that allows to attack a quantum-cryptographic connection. The described apparatus is capable of controlling free-space and fiber-based systems and minimize the amount of unwanted clicks in the system. With different control diagrams, we are able to achieve a different level of control. We further outline how the quality of active control of single-photon detectors can be characterized.

  12. A universal setup for active control of a single-photon detector

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qin; Skaar, Johannes [Department of Electronics and Telecommunications, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Lamas-Linares, Antía; Kurtsiefer, Christian [Centre for Quantum Technologies and Department of Physics, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Makarov, Vadim, E-mail: makarov@vad1.com [Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Gerhardt, Ilja, E-mail: ilja@quantumlah.org [Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart (Germany)

    2014-01-15

    The influence of bright light on a single-photon detector has been described in a number of recent publications. The impact on quantum key distribution (QKD) is important, and several hacking experiments have been tailored to fully control single-photon detectors. Special attention has been given to avoid introducing further errors into a QKD system. We describe the design and technical details of an apparatus which allows to attack a quantum-cryptographic connection. This device is capable of controlling free-space and fiber-based systems and of minimizing unwanted clicks in the system. With different control diagrams, we are able to achieve a different level of control. The control was initially targeted to the systems using BB84 protocol, with polarization encoding and basis switching using beamsplitters, but could be extended to other types of systems. We further outline how to characterize the quality of active control of single-photon detectors.

  13. Three-dimensional protein networks assembled by two-photon activation.

    Science.gov (United States)

    Gatterdam, Volker; Ramadass, Radhan; Stoess, Tatjana; Fichte, Manuela A H; Wachtveitl, Josef; Heckel, Alexander; Tampé, Robert

    2014-05-26

    Spatial and temporal control over chemical and biological processes plays a key role in life and material sciences. Here we synthesized a two-photon-activatable glutathione (GSH) to trigger the interaction with glutathione S-transferase (GST) by light at superior spatiotemporal resolution. The compound shows fast and well-confined photoconversion into the bioactive GSH, which is free to interact with GST-tagged proteins. The GSH/GST interaction can be phototriggered, changing its affinity over several orders of magnitude into the nanomolar range. Multiplexed three-dimensional (3D) protein networks are simultaneously generated in situ through two-photon fs-pulsed laser-scanning excitation. The two-photon activation facilitates the three-dimensional assembly of protein structures in real time at hitherto unseen resolution in time and space, thus opening up new applications far beyond the presented examples.

  14. Optical parametric oscillators in isotropic photonic crystals and cavities: 3D time domain analysis

    OpenAIRE

    Conti, Claudio; Di Falco, Andrea; Assanto, Gaetano

    2004-01-01

    We investigate optical parametric oscillations through four-wave mixing in resonant cavities and photonic crystals. The theoretical analysis underlines the relevant features of the phenomenon and the role of the density of states. Using fully vectorial 3D time-domain simulations, including both dispersion and nonlinear polarization, for the first time we address this process in a face centered cubic lattice and in a photonic crystal slab. The results lead the way to the development of novel p...

  15. Supermode analysis of the 18-core photonic crystal fiber laser

    Institute of Scientific and Technical Information of China (English)

    王远; 姚建铨; 郑一博; 温午麒; 陆颖; 王鹏

    2012-01-01

    The modal of 18-core photonic crystal fiber laser is discussed and calculated.And corresponding far-field distribution of the supermodes is given by Fresnel diffraction integral.For improving beam quality,the mode selection method based on the Talbot effect is introduced.The reflection coefficients are calculated,and the result shows that an in-phase supermode can be locked better at a large propagation distance.

  16. Analysis of thin-film photonic crystal microstructures

    CERN Document Server

    Pottage, J M

    2003-01-01

    Optical-scale microstructures containing thin-film photonic crystals (TFPCs) are modelled by transfer/scattering matrix methods, based on Fourier-series expansion of the optical Bloch eigenmodes. The majority of the TFPCs considered consist of 2D arrays of holes arranged in a triangular lattice, etched into high-index Al sub x Ga sub 1 sub - sub x As and placed on a low-index oxidised substrate. These TFPCs can be easily fabricated by standard electron-beam lithography techniques. Unlike most photonic crystal devices that have been proposed, our 'intra-pass-band' TFPCs would work by exploiting the somewhat surprising properties of propagating optical Bloch waves rather than directly relying on photonic bandgaps. By numerical modelling, it is demonstrated that 2D-patterned TFPCs can support highly dispersive high-Q quasi-guided and truly-guided resonant modes, and the unusual properties of these modes are explained in terms of their Bloch-wave compositions. Modal dispersion diagrams of TFPCs, showing the loci ...

  17. Remote Maneuver of Space Debris Using Photon Pressure for Active Collision Avoidance

    Science.gov (United States)

    Smith, C.

    2014-09-01

    The Space Environment Research Corporation (SERC) is a consortium of companies and research institutions that have joined together to pursue research and development of technologies and capabilities that will help to preserve the orbital space environment. The consortium includes, Electro Optics Systems (Australia), Lockheed Martin Australia, Optus Satellite Systems (Australia), The Australian national University, RMIT University, National Institute of Information and Communications Technology (NICT, Japan) as well as affiliates from NASA Ames and ESA. SERC is also the recipient of and Australian Government Cooperative Research Centre grant. SERC will pursue a wide ranging research program including technologies to improve tracking capability and capacity, orbit determination and propagation algorithms, conjunction analysis and collision avoidance. All of these technologies will contribute to the flagship program to demonstrate active collision avoidance using photon pressure to provide remote maneuver of space debris. This project joins of the proposed NASA Lightforce concept with infrastructure and capabilities provided by SERC. This paper will describe the proposed research and development program to provide an on-orbit demonstration within the next five years for remote maneuver of space debris.

  18. Active photonic devices based on colloidal semiconductor nanocrystals and organometallic halide perovskites

    Science.gov (United States)

    Suárez Alvarez, Isaac

    2016-10-01

    Semiconductor nanocrystals have arisen as outstanding materials to develop a new generation of optoelectronic devices. Their fabrication under simple and low cost colloidal chemistry methods results in cheap nanostructures able to provide a wide range of optical functionalities. Their attractive optical properties include a high absorption cross section below the band gap, a high quantum yield emission at room temperature, or the capability of tuning the band-gap with the size or the base material. In addition, their solution process nature enables an easy integration on several substrates and photonic structures. As a consequence, these nanoparticles have been extensively proposed to develop several photonic applications, such as detection of light, optical gain, generation of light or sensing. This manuscript reviews the great effort undertaken by the scientific community to construct active photonic devices based on these nanoparticles. The conditions to demonstrate stimulated emission are carefully studied by comparing the dependence of the optical properties of the nanocrystals with their size, shape and composition. In addition, this paper describes the design of different photonic architectures (waveguides and cavities) to enhance the generation of photoluminescence, and hence to reduce the threshold of optical gain. Finally, semiconductor nanocrystals are compared to organometallic halide perovskites, as this novel material has emerged as an alternative to colloidal nanoparticles.

  19. PECASE: Resonantly-Enhanced Lanthanide Emitters for Subwavelength-Scale, Active Photonics

    Science.gov (United States)

    2015-03-19

    AFRL-AFOSR-VA-TR-2016-0052 PECASE- RESONATLY-ENHANCHED LANTHANIDE EMITTERS FOR SUBWAVELENGTH-SCALE, ACTIVE Photonics Rashid Zia BROWN UNIVERSITY IN... Rashid Zia and Jonathan A. Kurvits 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION...during reporting period: [1] Christopher M. Dodson and Rashid Zia, “Magnetic dipole and electric quadrupole transitions in the trivalent lanthanide

  20. Maximum likelihood-based analysis of single-molecule photon arrival trajectories

    Science.gov (United States)

    Hajdziona, Marta; Molski, Andrzej

    2011-02-01

    In this work we explore the statistical properties of the maximum likelihood-based analysis of one-color photon arrival trajectories. This approach does not involve binning and, therefore, all of the information contained in an observed photon strajectory is used. We study the accuracy and precision of parameter estimates and the efficiency of the Akaike information criterion and the Bayesian information criterion (BIC) in selecting the true kinetic model. We focus on the low excitation regime where photon trajectories can be modeled as realizations of Markov modulated Poisson processes. The number of observed photons is the key parameter in determining model selection and parameter estimation. For example, the BIC can select the true three-state model from competing two-, three-, and four-state kinetic models even for relatively short trajectories made up of 2 × 103 photons. When the intensity levels are well-separated and 104 photons are observed, the two-state model parameters can be estimated with about 10% precision and those for a three-state model with about 20% precision.

  1. Energy Optimization And Calculation Of Dose Absorption Enhancement Factor In Photon Activation Therapy

    Directory of Open Access Journals (Sweden)

    Hassan Ranjbar

    2010-06-01

    Full Text Available Introduction: Secondary radiation such as photoelectrons, Auger electrons and characteristic radiations cause a local boost in dose for a tumor when irradiated with an external X-ray beam after being loaded with elements capable of activating the tumor, e.g.; I and Gd. Materials and Methods:  In this investigation, the MCNPX code was used for simulation and calculation of dose enhancement factor for a tumor loaded with activating elements. The designed model comprised the X-ray source, phantom (target tissue and loaded tumor with activating agent, detector, interactions modeling and results. The source was defined as monochromatic and plane surface situated at 50 cm (z = 50. Phantom geometry was a 10 × 10 × 10 cm3 cube centered at (0, 0, 0 with a 2.2 × 2.2 × 2.2 cm3 cubic tumor with a center located at 3 cm depth inside the phantom Results: Dose enhancement factor and optimum energy in radiotherapy are evaluated using the photon activation therapy method. Result show that the dose enhancement factor increases with activating concentration in the tumor. The maximum dose enhancement factor for iodine in the tumor occurs for photons in the energy range of 50-60 keV. Dose uniformity is less for lower energy photons within the activated region inside the tumor. Results indicate that the dose enhancement factor varies linearly with the activating concentration agent. Discussion and Conclusion: In this study, the obtained results point out a considerable enhancement in dose in the presence of activating agents in the tumor regions.

  2. Inspiration, imagination and implementation: International Year of Light activities of the Photonics Academy of Wales at Bangor (PAWB)

    Science.gov (United States)

    Davies, Ray; Shore, K. Alan

    2016-09-01

    Since the establishment of the Photonics Academy of Wales in 2005, several generations of participants have been encouraged to use their imagination in devising, designing and building novel photonics devices of benefit to society. In pursuing photonics projects within PAWB, the participants have gained a practical proficiency in photonics experimentation and photonics product design. The Photonics Academy of Wales @ Bangor ( PAWB) assumed responsibility for the coordination of a series of events in Wales, UK as part of global activities celebrating 2015 as the International Year of Light. PAWB has worked with several organisations and individuals to devise a programme of events which are focussed on conveying the significance of light and its technologies to a broad swathe of the population. These events take into account the bi-lingual nature of Wales with significant events being delivered in the Welsh language. Arrangement and delivery of the events has largely been undertaken on a voluntary basis albeit with some funding having been obtained from supportive bodies and organisations. The presentation will report on the events which were organised and also will present examples of novel photonics devices developed by students working with PAWB. Being aware of the importance of creating an on-going interest in the topics treated during the International Year of Light, some attention will also be given to legacy activities beyond 2015. A specific concern is the identification of effective mechanisms for engagement with photonics industry.

  3. Photonic crystal rod fibers: Understanding a new class of active optical waveguides

    DEFF Research Database (Denmark)

    Laurila, Marko

    In this PhD thesis an experimental study of modal characterization methods on large mode area photonic crystal fibers (PCFs) is performed and the development of a new ytterbium-doped photonic bandgap PCF rod fiber is presented. The first focus of this work is to use modal characterization methods...... core modes and the cladding band as the underlying mechanics to ensure SM operation of the new rod fiber design (85 μm core diameter), which was developed during this thesis work. The second focus of this work is the study of the new ytterbiumdoped rod fiber design under active operation. Performance...... of the rod fiber is evaluated in high power laser and laser amplifier configurations. The high power rod amplifier setup including the seed source is developed and characterized. Results obtained from the rod fiber showed simultaneously SM, near diffraction limited output beam quality with high average power...

  4. TiO2 activity enhancement through synergistic effect of photons localization of photonic crystals and the sensitization of CdS quantum dots

    Science.gov (United States)

    Li, Ping; Wang, Yuan; Wang, Ai-Jun; Chen, Sheng-Li

    2017-02-01

    In this work, the enhancement of TiO2 photocatalytic activity was studied through synergistic effect of the photons localization of photonic crystals and the sensitization of CdS quantum dots (CdS QDs). CdS QDs sensitized TiO2 membrane (denoted as CdS QDs/TiO2) was synthesized through doping the TiO2 membrane with CdS QDs by chemical bath deposition method (CBD). After TiO2 was sensitized with CdS QDs, the edge of light absorption of TiO2 was red-shifted to 470 nm and the light absorption in the range of 400 600 nm was higher than that of plain TiO2 membrane. Another type of composite membrane, CdS QDs/TiO2/SiO2 opal composite membrane was prepared by coupling SiO2 opal (a kind of photonic crystal) layer onto the CdS QDs/TiO2 membrane, and the photonic band gap of the SiO2 opal photonic crystal layer was deliberately planned at the electronic band gap of the CdS QDs. The photodegradation of gaseous CH3CHO (acetaldehyde) was used as probe reaction to test the photocatalytic activity of the as-prepared membranes, and the results showed that the CdS QDs sensitization can significantly improve the photocatalytic activity of TiO2 membrane under visible light irradiation, with the acetaldehyde degradation rate constant (k) on CdS QDs/TiO2 membranes being 1.59 times of that on plain TiO2 membranes. The acetaldehyde degradation rate constant on CdS QDs/TiO2/SiO2 opal composite membrane reached 4 times of that on plain TiO2 membrane. The photocatalytic activity of TiO2 membrane can be improved through synergistic effect of the photons localization of photonic crystals and the sensitization of CdS QDs.

  5. Comprehensive analysis of photonic effects on up-conversion of β-NaYF4:Er3+ nanoparticles in an organic-inorganic hybrid 1D photonic crystal

    Science.gov (United States)

    Hofmann, C. L. M.; Fischer, S.; Reitz, C.; Richards, B. S.; Goldschmidt, J. C.

    2016-04-01

    Upconversion (UC) presents a possibility to exploit sub-bandgap photons for current generation in solar cells by creating one high-energy photon out of at least two lower-energy photons. Photonic structures can enhance UC by two effects: a locally increased irradiance and a modified local density of photon states (LDOS). Bragg stacks are promising photonic structures for this application, because they are straightforward to optimize and overall absorption can be increased by adding more layers. In this work, we present a comprehensive simulation-based analysis of the photonic effects of a Bragg stack on UC luminescence. The investigated organic-inorganic hybrid Bragg stack consists of alternating layers of Poly(methylmethacrylate) (PMMA), containing purpose-built β-NaYF4:25% Er3+ core-shell nanoparticles and titanium dioxide (TiO2). From optical characterization of single thin layers, input parameters for simulations of the photonic effects are generated. The local irradiance enhancement and modulated LDOS are first simulated separately. Subsequently they are coupled in a rate equation model of the upconversion dynamics. Using the integrated model, UC luminescence is maximized by adapting the Bragg stack design. For a Bragg stack of only 5 bilayers, UC luminescence is enhanced by a factor of 3.8 at an incident irradiance of 2000 W/m2. Our results identify the Bragg stack as promising for enhancing UC, especially in the low-irradiance regime, relevant for the application in photovoltaics. Therefore, we experimentally realized optimized Bragg stack designs. The PMMA layers, containing UC nanoparticles, are produced via spin-coating from a toluene based solution. The TiO2 layers are produced by atomic layer deposition from molecular precursors. The reflectance measurements show that the realized Bragg stacks are in good agreement with predictions from simulation.

  6. Quasi-real-time photon pulse duration measurement by analysis of FEL radiation spectra

    Energy Technology Data Exchange (ETDEWEB)

    Engel, Robin, E-mail: robin.engel@uni-oldenburg.de [Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg (Germany); Institut für Physik, Carl von Ossietzky Universität Oldenburg, D-26111 Oldenburg (Germany); Institut für Laser und Optik, Hochschule Emden/Leer, University of Applied Sciences, Constantiaplatz 4, D-26723 Emden (Germany); Düsterer, Stefan; Brenner, Günter [Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg (Germany); Teubner, Ulrich [Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg (Germany); Institut für Physik, Carl von Ossietzky Universität Oldenburg, D-26111 Oldenburg (Germany); Institut für Laser und Optik, Hochschule Emden/Leer, University of Applied Sciences, Constantiaplatz 4, D-26723 Emden (Germany)

    2016-01-01

    Considering the second-order spectral correlation function of SASE-FEL radiation allows a real-time observation of the photon pulse duration during spectra acquisition. For photon diagnostics at free-electron lasers (FELs), the determination of the photon pulse duration is an important challenge and a complex task. This is especially true for SASE FELs with strongly fluctuating pulse parameters. However, most techniques require an extensive experimental setup, data acquisition and evaluation time, limiting the usability in all-day operation. In contrast, the presented work uses an existing approach based on the analysis of statistical properties of measured SASE FEL spectra and implements it as a software tool, integrated in FLASH’s data acquisition system. This allows the calculation of the average pulse durations from a set of measured spectral distributions with only seconds of delay, whenever high-resolution spectra are recorded.

  7. Active photonic sensor communication cable for field application of optical data and power transmission

    Science.gov (United States)

    Suthau, Eike; Rieske, Ralf; Zerna, Thomas

    2014-10-01

    Omitting electrically conducting wires for sensor communication and power supply promises protection for sensor systems and monitored structures against lightning or high voltages, prevention of explosion hazards, and reduction of susceptibility to tampering. The ability to photonically power remote systems opens up the full range of electrical sensors. Power-over-fiber is an attractive option in electromagnetically sensitive environments, particularly for longterm, maintenance-free applications. It can deliver uninterrupted power sufficient for elaborate sensors, data processing or even actuators alongside continuous high speed data communication for remote sensor application. This paper proposes an active photonic sensor communication system, which combines the advantages of optical data links in terms of immunity to electromagnetic interference (EMI), high bandwidth, hardiness against tampering or eavesdropping, and low cable weight with the robustness one has come to expect from industrial or military electrical connectors. An application specific integrated circuit (ASIC) is presented that implements a closed-loop regulation of the sensor power supply to guarantee continuous, reliable data communications while maintaining a highly efficient, adaptive sensor supply scheme. It is demonstrated that the resulting novel photonic sensor communication cable can handle sensors and actuators differing orders of magnitude with respect to power consumption. The miniaturization of the electro-optical converters and driving electronics is as important to the presented development as the energy efficiency of the detached, optically powered sensor node. For this reason, a novel photonic packaging technology based on wafer-level assembly of the laser power converters by means of passive alignment will be disclosed in this paper.

  8. Note: Fully integrated active quenching circuit achieving 100 MHz count rate with custom technology single photon avalanche diodes

    Science.gov (United States)

    Acconcia, G.; Labanca, I.; Rech, I.; Gulinatti, A.; Ghioni, M.

    2017-02-01

    The minimization of Single Photon Avalanche Diodes (SPADs) dead time is a key factor to speed up photon counting and timing measurements. We present a fully integrated Active Quenching Circuit (AQC) able to provide a count rate as high as 100 MHz with custom technology SPAD detectors. The AQC can also operate the new red enhanced SPAD and provide the timing information with a timing jitter Full Width at Half Maximum (FWHM) as low as 160 ps.

  9. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    For the application of photon to industrial technologies, in particular, a hard photon technology was surveyed which uses photon beams of 0.1-200nm in wavelength. Its features such as selective atom reaction, dense inner shell excitation and spacial high resolution by quantum energy are expected to provide innovative techniques for various field such as fine machining, material synthesis and advanced inspection technology. This wavelength region has been hardly utilized for industrial fields because of poor development of suitable photon sources and optical devices. The developmental meaning, usable time and issue of a hard photon reduction lithography were surveyed as lithography in ultra-fine region below 0.1{mu}m. On hard photon analysis/evaluation technology, the industrial use of analysis, measurement and evaluation technologies by micro-beam was viewed, and optimum photon sources and optical systems were surveyed. Prediction of surface and surface layer modification by inner shell excitation, the future trend of this process and development of a vacuum ultraviolet light source were also surveyed. 383 refs., 153 figs., 17 tabs.

  10. QCD analysis and effective temperature of direct photons in lead-lead collisions at the LHC

    CERN Document Server

    Klasen, M; König, F; Wessels, J P

    2014-01-01

    We present a systematic theoretical analysis of the ALICE measurement of low-$p_T$ direct-photon production in central lead-lead collisions at the LHC with a centre-of-mass energy of $\\sqrt{s_{NN}}=2.76$ TeV. Using next-to-leading order of perturbative QCD, we compute the relative contributions to prompt-photon production from different initial and final states and the theoretical uncertainties coming from independent variations of the renormalisation and factorisation scales, the nuclear parton densities and the fragmentation functions. Based on different fits to the unsubtracted and prompt-photon subtracted ALICE data, we consistently find an exponential, possibly thermal, photon spectrum from the quark-gluon plasma (or hot medium) with slope $T=304\\pm 58$ MeV and $309\\pm64$ MeV at $p_T\\in[0.8;2.2]$ GeV and $p_T\\in[1.5;3.5]$ GeV as well as a power-law ($p_T^{-4}$) behavior for $p_T>4$ GeV as predicted by QCD hard scattering.

  11. Analysis of the factors that affect photon counts in Compton scattering.

    Science.gov (United States)

    Luo, Guang; Xiao, Guangyu

    2014-10-30

    Compton scattering has been applied in a variety of fields. The factors that affect Compton scattering have been studied extensively in the literature. However, the factors that affect the measured photon counts in Compton scattering are rarely considered. In this paper, we make a detailed discussion on those factors. First, Compton scattering experiments of some alloy series and powder mixture series are explored. Second, the electron density is researched in terms of atom and lattice constants. Third, the factor of attenuation coefficient is discussed. And then, the active degree of electrons is discussed based on the DFT theory. Lastly, the conclusions are made, that the factors affecting Compton scattering photon counts include mainly electron number density, attenuation coefficient and active degree of electrons.

  12. Controlling an actively-quenched single photon detector with bright light.

    Science.gov (United States)

    Sauge, Sebastien; Lydersen, Lars; Anisimov, Andrey; Skaar, Johannes; Makarov, Vadim

    2011-11-01

    We control using bright light an actively-quenched avalanche single-photon detector. Actively-quenched detectors are commonly used for quantum key distribution (QKD) in the visible and near-infrared range. This study shows that these detectors are controllable by the same attack used to hack passively-quenched and gated detectors. This demonstrates the generality of our attack and its possible applicability to eavsdropping the full secret key of all QKD systems using avalanche photodiodes (APDs). Moreover, the commercial detector model we tested (PerkinElmer SPCM-AQR) exhibits two new blinding mechanisms in addition to the previously observed thermal blinding of the APD, namely: malfunctioning of the bias voltage control circuit, and overload of the DC/DC converter biasing the APD. These two new technical loopholes found just in one detector model suggest that this problem must be solved in general, by incorporating generally imperfect detectors into the security proof for QKD.

  13. Stepwise multi-photon activation fluorescence reveals a new method of melanoma imaging for dermatologists

    Science.gov (United States)

    Lai, Zhenhua; Lian, Christine; Ma, Jie; Yu, Jingyi; Gu, Zetong; Rajadhyaksha, Milind; DiMarzio, Charles A.

    2014-02-01

    Previous research has shown that the stepwise multi-photon activated fluorescence (SMPAF) of melanin, activated by a continuous-wave (CW) mode near infrared (NIR) laser, is a low cost and reliable method of detecting melanin. SMPAF images of melanin in a mouse hair and a formalin fixed mouse melanoma were compared with conventional multiphoton fluorescence microscopy (MPFM) images and confocal reflectance microscopy (CRM) images, all of which were acquired at an excitation wavelength of 920 nm, to further prove the effectiveness of SMPAF in detecting melanin. SMPAF images add specificity for melanin detection to MPFM images and CRM images. Melanin SMPAF can be a promising technology to enable melanoma imaging for dermatologists.

  14. Analysis of Higher Order Channel Dropping Tunneling Processes in Photonic Crystals

    Institute of Scientific and Technical Information of China (English)

    FU Jian; HE Sai-Ling

    2000-01-01

    A theoretical analysis is given for a higher order channel drop tunneling structure composed of two horizontal channels and a resonator system with two vertical multi-mode cavities in a two- or three-dimensional photonic crystal. Criteria for a complete transfer are derived for the application of wavelength division multiplexing. Compared to the resonator system with two single-mode cavities or a single multi-mode cavity, the present resonator system improves the transport properties.

  15. Monolithic active quenching and picosecond timing circuit suitable for large-area single-photon avalanche diodes.

    Science.gov (United States)

    Gallivanoni, A; Rech, I; Resnati, D; Ghioni, M; Cova, S

    2006-06-12

    A new integrated active quenching circuit (i-AQC) designed in a standard CMOS process is presented, capable of operating with any available single photon avalanche diode (SPAD) over wide temperature range. The circuit is suitable for attaining high photon timing resolution also with wide-area SPADs. The new i-AQC integrates the basic active-quenching loop, a patented low-side timing circuit comprising a fast pulse pick-up scheme that substantially improves time-jitter performance, and a novel active-load passive quenching mechanism (consisting of a current mirror rather than a traditional high-value resistor) greatly improves the maximum counting rate. The circuit is also suitable for portable instruments, miniaturized detector modules and SPAD-array detectors. The overall features of the circuit may open the way to new developments in diversified applications of time-correlated photon counting in life sciences and material sciences.

  16. Cell flow analysis with a two-photon fluorescence fiber probe

    Science.gov (United States)

    Chang, Yu-Chung; Ye, Jing Yong; Thomas, Thommey P.; Baker, James R., Jr.; Norris, Theodore B.

    2010-11-01

    We report the use of a sensitive double-clad fiber (DCF) probe for in situ cell flow velocity measurements and cell analysis by means of two-photon excited fluorescence correlation spectroscopy (FCS). We have demonstrated the feasibility to use this fiber probe for in vivo two-photon flow cytometry previously. However, because of the viscosity of blood and the non-uniform flow nature in vivo, it is problematic to use the detected cell numbers to estimate the sampled blood volume. To precisely calibrate the sampled blood volume, it is necessary to conduct real time flow velocity measurement. We propose to use FCS technique to measure the flow velocity. The ability to measure the flow velocities of labeled cells in whole blood has been demonstrated. Our two-photon fluorescence fiber probe has the ability to monitor multiple fluorescent biomarkers simultaneously. We demonstrate that we can distinguish differently labeled cells by their distinct features on the correlation curves. The ability to conduct in situ cell flow analysis using the fiber probe may be useful in disease diagnosis or further comprehension of the circulation system.

  17. Mechanism Analysis of the Inverse Doppler Effect in Two-Dimensional Photonic Crystal based on Phase Evolution

    Science.gov (United States)

    Jiang, Qiang; Chen, Jiabi; Wang, Yan; Liang, Binming; Hu, Jinbing; Zhuang, Songlin

    2016-04-01

    Although the inverse Doppler effect has been observed experimentally at optical frequencies in photonic crystal with negative effective refractive index, its explanation is based on phenomenological theory rather than a strict theory. Elucidating the physical mechanism underlying the inverse Doppler shift is necessary. In this article, the primary electrical field component in the photonic crystal that leads to negative refraction was extracted, and the phase evolution of the entire process when light travels through a moving photonic crystal was investigated using static and dynamic finite different time domain methods. The analysis demonstrates the validity of the use of np (the effective refractive index of the photonic crystal in the light path) in these calculations, and reveals the origin of the inverse Doppler effect in photonic crystals.

  18. Analysis of Photonic Networks for a Chip Multiprocessor Using Scientific Applications

    Energy Technology Data Exchange (ETDEWEB)

    Kamil, Shoaib A; Hendry, Gilbert; Biberman, Aleksandr; Chan, Johnnie; Lee, Benjamin G.; Mohiyuddin, Marghoob; Jain, Ankit; Bergman, Keren; Carloni, Luca; Kubiatowicz, John; Oliker, Leonid; Shalf, John

    2009-01-31

    As multiprocessors scale to unprecedented numbers of cores in order to sustain performance growth, it is vital that these gains are not nullified by high energy consumption from inter-core communication. With recent advances in 3D Integration CMOS technology, the possibility for realizing hybrid photonic-electronic networks-on-chip warrants investigating real application traces on functionally comparable photonic and electronic network designs. We present a comparative analysis using both synthetic benchmarks as well as real applications, run through detailed cycle accurate models implemented under the OMNeT++ discrete event simulation environment. Results show that when utilizing standard process-to-processor mapping methods, this hybrid network can achieve 75X improvement in energy efficiency for synthetic benchmarks and up to 37X improvement for real scientific applications, defined as network performance per energy spent, over an electronic mesh for large messages across a variety of communication patterns.

  19. Engineering near-infrared single-photon emitters with optically active spins in ultrapure silicon carbide

    Science.gov (United States)

    Fuchs, F.; Stender, B.; Trupke, M.; Simin, D.; Pflaum, J.; Dyakonov, V.; Astakhov, G. V.

    2015-07-01

    Vacancy-related centres in silicon carbide are attracting growing attention because of their appealing optical and spin properties. These atomic-scale defects can be created using electron or neutron irradiation; however, their precise engineering has not been demonstrated yet. Here, silicon vacancies are generated in a nuclear reactor and their density is controlled over eight orders of magnitude within an accuracy down to a single vacancy level. An isolated silicon vacancy serves as a near-infrared photostable single-photon emitter, operating even at room temperature. The vacancy spins can be manipulated using an optically detected magnetic resonance technique, and we determine the transition rates and absorption cross-section, describing the intensity-dependent photophysics of these emitters. The on-demand engineering of optically active spins in technologically friendly materials is a crucial step toward implementation of both maser amplifiers, requiring high-density spin ensembles, and qubits based on single spins.

  20. Partial wave analysis of 3 π with pion and photon beams

    Science.gov (United States)

    Jackura, Andrew; Mikhasenko, Mikhail; Szczepaniak, Adam; Ketzer, Bernhard; Joint Physics Analysis Center Collaboration

    2016-09-01

    We present some results on the analysis of 3 π resonances from peripheral scattering of pions off of nuclear targets. The analysis is motivated by the recent release of the largest data set on diffractively produced three pions by the COMPASS collaboration. The model emphasizes the 3 π production process and their final state interactions which satisfy S-matrix principles. We apply our model to fit partial wave intensities and relative phases from COMPASS in the JPC =2-+ sector and search for resonances. We then discuss the extension of our formalism to photon beams to be used in the GlueX experiment.

  1. Temporal coupled mode analysis of one-dimensional magneto-photonic crystals with cavity structures

    Science.gov (United States)

    Saghirzadeh Darki, Behnam; Zeidaabadi Nezhad, Abolghasem; Firouzeh, Zaker Hossein

    2016-12-01

    In this paper, we propose the time-dependent coupled mode analysis of one-dimensional magneto-photonic crystals including one, two or multiple defect layers. The performance of the structures, namely the total transmission, Faraday rotation and ellipticity, is obtained using the proposed method. The results of the developed analytic approach are verified by comparing them to the results of the exact numerical transfer matrix method. Unlike the widely used numerical method, our proposed analytic method seems promising for the synthesis as well as the analysis purposes. Moreover, the proposed method has not the restrictions of the previously examined analytic methods.

  2. Temperature dependence of active photonic band gap in bragg-spaced quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Hu Zhiqiang; Wang Tao; Yu Chunchao; Xu Wei, E-mail: huzhiqianghzq@163.com [Wuhan National Laboratory for Optoelectronics, College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei (China)

    2011-02-01

    A novel all-optical polarization switch of active photonic band gap structure based on non-resonant optical Stark effect bragg-spaced quantum wells was investigated and it could be compatible with the optical communication system. The theory is based on InGaAsP/InP Bragg-spaced quantum wells (BSQWs). Mainly through the design of the InGaAsP well layer component and InP barrier thickness to make the quantum-period cycle meet the bragg condition and the bragg frequency is equal to re-hole exciton resonance frequency. When a spectrally narrow control pulse is tuned within the forbidden gap, such BSQWs have been shown to exhibit large optical nonlinearities and ps recovery times, which can form T hz switch. However, the exciton binding energy of InGaAsP will be automatically separate at room temperature, so the effect of all-optical polarization switching of active photonic band gap bragg structure quantum wells can only be studied at low temperature. By a large number of experiments, we tested part of the material parameters of BSQWs in the temperature range 10-300K. On this basis, the InGaAsP and InP refractive index changes with wavelength, InP thermal expansion coefficient are studied and a relationship equation is established. Experimental results show that the bragg reflection spectra with temperature mainly is effected by InP refractive index changes with temperature. Our theoretical study and experiment are an instruction as a reference in the designs and experiments of future practical optical switches.

  3. Active layer identification of photonic crystal waveguide biosensor chip for the detection of Escherichia coli

    Science.gov (United States)

    Painam, Balveer; Kaler, Rajinder S.; Kumar, Mukesh

    2016-07-01

    This work represents experimental and simulation analysis of photonic crystal waveguide (PCW)-based biosensor structures, which is used for detection of the Escherichia coli (E. coli) cell. A method is adopted for E. coli culture to measure length, diameter, and refractive index to finalize the structural design and to verify the suitability of PCW as a biosensor. This method is tested using DH5α strains of E. coli. The typical precisions of measurements are varied in ranges from 1.132 to 1.825 μm and from 0.447 to 0.66 μm for pathogen's length and diameter, respectively. The measured distribution of samples over length and diameter are in correlation with the measurements performed by scanning electron microscope. After obtaining average length and diameter of cylindrical shaped E. coli cell, we consider these values for simulation analysis of designed PCW biosensor. E. coli cell is trapped in the middle of the PCW biosensor having three different types of waveguides, i.e., gallium arsenide/silicon dioxide (GaAs/SiO2), silicon/silicon dioxide (Si/SiO2), or silicon nitride/silicon dioxide (Si3N4/SiO2) to observe the maximum resonance shift and sensitivity. It is observed from the simulation data analysis that GaAs/SiO2 is the preferred PCW biosensor for the identification of E. coli.

  4. Synthetic oligomer analysis using atmospheric pressure photoionization mass spectrometry at different photon energies

    Energy Technology Data Exchange (ETDEWEB)

    Desmazières, Bernard [Global Bioenergies, 5 rue Henri Desbruyeres, 91030 Evry (France); Legros, Véronique [CNRS, UMR8587, Université d’Evry-Val-d’Essonne, Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, F-91025 Evry (France); Giuliani, Alexandre [Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, 91192 Gif-sur-Yvette (France); UAR1008, CEPIA, INRA, Rue de la Geraudiere, F-44316 Nantes (France); Buchmann, William, E-mail: william.buchmann@univ-evry.fr [CNRS, UMR8587, Université d’Evry-Val-d’Essonne, Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, F-91025 Evry (France)

    2014-01-15

    Graphical abstract: Atmospheric pressure photoIonization mass spectra of synthetic oligomers were recorded in the negative mode by varying the photon energy using synchrotron radiation. Photon energy required for an efficient ionization of the polymer was correlated to ionization potential of the solvent (for example 9.4 eV for tetrahydrofuran). -- Highlights: •Atmospheric pressure photoionization was performed using synchrotron radiation. •Photoionization of oligomers in THF with 10% CH{sub 2}Cl{sub 2} produces intact [M + Cl]{sup −} ions. •The photon energy required corresponds to ionization potential of the solvent. •Polymer distributions depend on source parameters such T °C and applied voltages. •Liquid chromatography was coupled to MS using an APPI interface for polymer analysis. -- Abstract: Atmospheric pressure photoionization (APPI) followed by mass spectrometric detection was used to ionize a variety of polymers: polyethylene glycol, polymethyl methacrylate, polystyrene, and polysiloxane. In most cases, whatever the polymer or the solvent used (dichloromethane, tetrahydrofuran, hexane, acetone or toluene), only negative ion mode produced intact ions such as chlorinated adducts, with no or few fragmentations, in contrast to the positive ion mode that frequently led to important in-source fragmentations. In addition, it was shown that optimal detection of polymer distributions require a fine tuning of other source parameters such as temperature and ion transfer voltage. Series of mass spectra were recorded in the negative mode, in various solvents (dichloromethane, tetrahydrofuran, hexane, toluene, and acetone), by varying the photon energy from 8 eV up to 10.6 eV using synchrotron radiation. To these solvents, addition of a classical APPI dopant (toluene or acetone) was not necessary. Courtesy of the synchrotron radiation, it was demonstrated that the photon energy required for an efficient ionization of the polymer was correlated to the

  5. Photonic crystals

    CERN Document Server

    Busch, Kurt; Wehrspohn, Ralf B; Föll, Helmut

    2006-01-01

    The majority of the contributions in this topically edited book stems from the priority program SPP 1113 ""Photonische Kristalle"" run by the Deutsche Forschungsgemeinschaft (DFG), resulting in a survey of the current state of photonic crystal research in Germany. The first part of the book describes methods for the theoretical analysis of their optical properties as well as the results. The main part is dedicated to the fabrication, characterization and modeling of two- and three-dimensional photonic crystals, while the final section presents a wide spectrum of applications: gas sensors, micr

  6. Analysis on characteristics of 1-D apodized and chirped photonic crystals containing negative refractive materials

    Institute of Scientific and Technical Information of China (English)

    TONG Kai; CUI Wei-wei; XU Xiao-hui; LI Zhi-quan

    2008-01-01

    Using transfer matrix method, the optical transmission properties of 1-D photonic crystals composed partially of negativerefraction media are analyzed. The transmission spectra of periodic photonic crystal, chirped photonic crystal and apodizedphotonic crystal are numerically simulated respectively. By contrast with optical transmission properties of ordinary photo-nic crystals made of positive refraction media, the transmission spectra of apodized photonic crystal become unregular, theBragg flat-headed area recurs but the peak of transmission does not change significantly. Futhermore, the band gap rangeof chirped photonic crystal diminishes gradually.

  7. Variability analysis of device-level photonics using stochastic collocation (Conference Presentation)

    Science.gov (United States)

    Xing, Yufei; Spina, Domenico; Li, Ang; Dhaene, Tom; Bogaerts, Wim

    2016-05-01

    Abstract Integrated photonics, and especially silicon photonics, has been rapidly expanded its catalog of building blocks and functionalities. Now, it is maturing fast towards circuit-level integration to serve more complex applications in industry. However, performance variability due to the fabrication process and operational conditions can limit the yield of large-scale circuits. It is essential to assess this impact at the design level with an efficient variability analysis: how variations in geometrical, electrical and optical parameters propagate into components performance. In particular when implementing wavelength-selective filters, many primary functional parameters are affected by fabrication-induced variability. The key functional parameters that we assess in this paper are the waveguide propagation constant (the effective index, essential to define the exact length of a delay line) and the coupling coefficients in coupling structure (necessary to set the power distribution over different delay lines). The Monte Carlo (MC) method is the standard method for variability analysis, thanks to its accuracy and easy implementation. However, due to its slow convergence, it requires a large set of samples (simulations or measurements), making it computationally or experimentally expensive. More efficient methods to assess such variability can be used, such as generalized polynomial chaos (gPC) expansion or stochastic collocation. In this paper, we demonstrate stochastic collocation (SC) as an efficient alternative to MC or gPC to characterize photonic devices under the effect of uncertainty. The idea of SC is to interpolate stochastic solutions in the random space by interpolation polynomials. After sampling the deterministic problem at a pre-defined set of nodes in random space, the interpolation is constructed. SC drastically reduces computation and measurement cost. Also, like MC method, sampling-based SC is easy to implement. Its computation cost can be

  8. Design and analysis of a wideband photonic crystal waveguide with low group-velocity and low dispersion

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The slow light propagation in a line waveguide in the two-dimensional triangular photonic crystal has been numerically studied, based on which a wideband photonic crystal waveguide with low group-velocity and low dispersion is proposed. The numerical simulation analysis shows that it is possible to maximize the group index and minimize the group-velocity dispersion in wide bandwidth by increasing the radius of the basic air hole and changing the position of the first two rows of air holes in photonic crystal waveguides. Such a photonic crystal waveguide exhibits low group velocity and low group-velocity dispersion over a broad wavelength range. A larger group index-bandwidth product is achieved in this type of waveguide structure. The numerically computed results present the normalized bandwidth as 0.32%, 0.48% and 0.642% corresponding to the group index of 85, 58 and 45, respectively.

  9. Mission analysis and performance comparison for an Advanced Solar Photon Thruster

    Science.gov (United States)

    Dachwald, Bernd; Wurm, Patrick

    2011-12-01

    The so-called "compound solar sail", also known as "Solar Photon Thruster" (SPT), is a design concept, for which the two basic functions of the solar sail, namely light collection and thrust direction, are uncoupled. In this paper, we introduce a novel SPT concept, termed the Advanced Solar Photon Thruster (ASPT), which does not suffer from the simplified assumptions that have been made for the analysis of compound solar sails in previous studies. After having presented the equations that describe the force on the ASPT and after having performed a detailed design analysis, the performance of the ASPT with respect to the conventional flat solar sail (FSS) is investigated for three interplanetary mission scenarios: an Earth-Venus rendezvous, where the solar sail has to spiral towards the Sun, an Earth-Mars rendezvous, where the solar sail has to spiral away from the Sun, and an Earth-NEA rendezvous (to near-Earth asteroid 1996FG3), where a large change in orbital eccentricity is required. The investigated solar sails have realistic near-term characteristic accelerations between 0.1 and 0.2 mm/s 2. Our results show that an SPT is not superior to the flat solar sail unless very idealistic assumptions are made.

  10. Field analysis of TE and TM modes in photonic crystal Bragg fibers by transmission matrix method

    Directory of Open Access Journals (Sweden)

    M Hosseini Farzad

    2010-03-01

    Full Text Available In this article, we considered the field analysis in photonic crystal Bragg fibers. We apply the method of transmission matrix to calculater the dispersion curves, the longitudinal wave number over wave number versus incident wavelength, and the field distributions of TE and TM modes in the Bragg fiber. Our analysis shows that the field of guided modes is confined in the core and can exist only in particular wavelength bands corresponding to the band-gap of the periodic structure of the clad. From another point of view, light confinement is due to Bragg reflection from high-and low-refractive index layers of the clad. Also, the diagram of average angular frequency with respect to average longitudinal wave number is plotted so that the band gap regions of the clad are clearly observed.

  11. SAVANT analysis of the microelectronics and photonics testbed solar cell data

    Energy Technology Data Exchange (ETDEWEB)

    Walters, Robert J.; Summers, G.P. [Naval Research Lab., Code 6818, Washington, DC (United States); Messenger, S.R. [SFA, Inc., Largo, MD (United States); Morton, T.L. [Ohio Aerospace Inst., Cleveland, OH (United States)

    2005-07-01

    An analysis of solar array data from the Microelectronic and Photonic Testbed (MPTB) space experiment is presented. The data are analyzed using the displacement damage dose (D{sub d}) methodology developed by the US Naval Research Laboratory (NRL) as implemented in the Solar Array Verification and Analysis Tool (SAVANT). SAVANT is a WindowsTM-based computer code that predicts the on-orbit performance of a solar cell in a specified Earth orbit. The predicted solar cell performance produced by the SAVANT code are compared with the measured on-orbit data. In addition, the calculated data are compared with onboard dosimeter measurements. The results allow both a validation of the SAVANT code and a comparison of the space environment models with measured on-orbit data. The results show the models to match the measured data within a factor of 2. (Author)

  12. Photon-photon collisions

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J.

    1988-07-01

    Highlights of the VIIIth International Workshop on Photon-Photon Collisions are reviewed. New experimental and theoretical results were reported in virtually every area of ..gamma gamma.. physics, particularly in exotic resonance production and tests of quantum chromodynamics where asymptotic freedom and factorization theorems provide predictions for both inclusive and exclusive ..gamma gamma.. reactions at high momentum transfer. 73 refs., 12 figs.

  13. Wavelet-based analysis of transient electromagnetic wave propagation in photonic crystals.

    Science.gov (United States)

    Shifman, Yair; Leviatan, Yehuda

    2004-03-01

    Photonic crystals and optical bandgap structures, which facilitate high-precision control of electromagnetic-field propagation, are gaining ever-increasing attention in both scientific and commercial applications. One common photonic device is the distributed Bragg reflector (DBR), which exhibits high reflectivity at certain frequencies. Analysis of the transient interaction of an electromagnetic pulse with such a device can be formulated in terms of the time-domain volume integral equation and, in turn, solved numerically with the method of moments. Owing to the frequency-dependent reflectivity of such devices, the extent of field penetration into deep layers of the device will be different depending on the frequency content of the impinging pulse. We show how this phenomenon can be exploited to reduce the number of basis functions needed for the solution. To this end, we use spatiotemporal wavelet basis functions, which possess the multiresolution property in both spatial and temporal domains. To select the dominant functions in the solution, we use an iterative impedance matrix compression (IMC) procedure, which gradually constructs and solves a compressed version of the matrix equation until the desired degree of accuracy has been achieved. Results show that when the electromagnetic pulse is reflected, the transient IMC omits basis functions defined over the last layers of the DBR, as anticipated.

  14. Single Photon Counting Performance and Noise Analysis of CMOS SPAD-Based Image Sensors.

    Science.gov (United States)

    Dutton, Neale A W; Gyongy, Istvan; Parmesan, Luca; Henderson, Robert K

    2016-07-20

    SPAD-based solid state CMOS image sensors utilising analogue integrators have attained deep sub-electron read noise (DSERN) permitting single photon counting (SPC) imaging. A new method is proposed to determine the read noise in DSERN image sensors by evaluating the peak separation and width (PSW) of single photon peaks in a photon counting histogram (PCH). The technique is used to identify and analyse cumulative noise in analogue integrating SPC SPAD-based pixels. The DSERN of our SPAD image sensor is exploited to confirm recent multi-photon threshold quanta image sensor (QIS) theory. Finally, various single and multiple photon spatio-temporal oversampling techniques are reviewed.

  15. Theoretical analysis on two-photon absorption spectroscopy in a confined four-level atomic system

    Institute of Scientific and Technical Information of China (English)

    Yuanyuan Li; Jintao Bai; Li Li; Yanpeng Zhang; Xun Hou

    2009-01-01

    We investigate theoretically two-photon absorption spectroscopy modified by a control field in a confined Y-type four-level system. Dicke-narrowing effect occurs both in two-photon absorption lines and the dips of transparency against two-photon absorption due to enhanced contribution of slow atoms. We also find that the suppression and the enhancement of two-photon absorption can be modified by changing the strength of the control field and the detuning of three laser fields. This control of two-photon absorption may have some applications in information processing and optical devices.

  16. Active Ageing: An Analysis

    Directory of Open Access Journals (Sweden)

    Alina-Cristina Nuta

    2011-10-01

    Full Text Available The problem of ageing is a highly topical for Romania and for European Union. In this framework, to create and implement some strategies for active ageing is an important objective. The international and regional forums set (supported by official statistics that the number of older people growing rapidly. Romania needs some programmes (with labour, social, economic, health care aspects to deal with the demographic changes, programs that will reform the existing working life structures and legislation. Despite the actual pension reform, which tries to close the opportunity of early retirement (by penalizing the total pension flows, or increasing the retirement age, etc., the labour system does not sets some important targets for this area.

  17. Continuous outreach activities performed by a student project team of undergraduates and their program topics in optics and photonics

    Science.gov (United States)

    Hasegawa, Makoto; Tokumitsu, Seika

    2016-09-01

    The out-of-curriculum project team "Rika-Kobo", organized by undergraduate students, has been actively engaged in a variety of continuous outreach activities in the fields of science and technology including optics and photonics. The targets of their activities cover wide ranges of generations from kids to parents and elderly people, with aiming to promote their interests in various fields of science and technologies. This is an out-of-curriculum project team with about 30 to 40 undergraduate students in several grades and majors. The total number of their activities per year tends to reach 80 to 90 in recent years. Typical activities to be performed by the project team include science classes in elementary and/or secondary schools, science classes at other educational facilities such as science museums, and experiment demonstrations at science events. Popular topics cover wide ranges from explanations and demonstrations of nature phenomena, such as rainbow colors, blue sky, sunset color, to demonstration experiments related to engineering applications, such as polarization of light, LEDs, and optical communications. Experimental topics in optics and photonics are especially popular to the audiences. Those activities are very effective to enhance interests of the audiences in learning related knowledges, irrespective of their generations. Those activities are also helpful for the student members to achieve and/or renew scientific knowledges. In addition, each of the activities provides the student members with effective and advantageous Project-Based-Learning (PBL) style experiences including manufacturing experiences, which are advantageous to cultivate their engineering skills.

  18. Sensitive multiplex detection of serological liver cancer biomarkers using SERS-active photonic crystal fiber probe.

    Science.gov (United States)

    Dinish, U S; Balasundaram, Ghayathri; Chang, Young Tae; Olivo, Malini

    2014-11-01

    Surface-enhanced Raman scattering (SERS) spectroscopy possesses the most promising advantage of multiplex detection for biosensing applications, which is achieved due to the narrow 'fingerprint' Raman spectra from the analyte molecules. We developed an ultrasensitive platform for the multiplex detection of cancer biomarkers by combining the SERS technique with a hollow-core photonic crystal fiber (HCPCF). Axially aligned air channels inside the HCPCF provide an excellent platform for optical sensing using SERS. In addition to the flexibility of optical fibers, HCPCF provides better light confinement and a larger interaction length for the guided light and the analyte, resulting in an improvement in sensitivity to detect low concentrations of bioanalytes in extremely low sample volumes. Herein, for the first time, we demonstrate the sensitive multiplex detection of biomarkers immobilized inside the HCPCF using antibody-conjugated SERS-active nanoparticles (SERS nanotags). As a proof-of-concept for targeted multiplex detection, initially we carried out the sensing of epidermal growth factor receptor (EGFR) biomarker in oral squamous carcinoma cell lysate using three different SERS nanotags. Subsequently, we also achieved simultaneous detection of hepatocellular carcinoma (HCC) biomarkers-alpha fetoprotein (AFP) and alpha-1-antitrypsin (A1AT) secreted in the supernatant from Hep3b cancer cell line. Using a SERS-HCPCF sensing platform, we could successfully demonstrate the multiplex detection in an extremely low sample volume of ∼20 nL. In future, this study may lead to sensitive biosensing platform for the low concentration detection of biomarkers in an extremely low sample volume of body fluids to achieve early diagnosis of multiple diseases. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim).

  19. Synthesis, characterization and preclinical studies of two-photon-activated targeted PDT therapeutic triads

    Science.gov (United States)

    Spangler, C. W.; Starkey, J. R.; Rebane, A.; Meng, F.; Gong, A.; Drobizhev, M.

    2006-02-01

    Photodynamic therapy (PDT) continues to evolve into a mature clinical treatment of a variety of cancer types as well as age-related macular degeneration of the eye. However, there are still aspects of PDT that need to be improved in order for greater clinical acceptance. While a number of new PDT photo-sensitizers, sometimes referred to as second- or third- generation therapeutic agents, are currently under clinical investigation, the direct treatment through the skin of subcutaneous tumors deeper than 5 mm remains problematic. Currently approved PDT porphyrin photo-sensitizers, as well as several modified porphyrins (e.g. chlorins, bacteriochlorins, etc.) that are under clinical investigation can be activated at 630-730 nm, but none above 800 nm. It would be highly desirable if new PDT paradigms could be developed that would allow photo-activation deep in the tissue transparency window in the Near-infrared (NIR) above 800 nm to reduce scattering and absorption phenomena that reduce deep tissue PDT efficacy. Rasiris and MPA Technologies have developed new porphyrins that have greatly enhanced two-photon absorption ( P A ) cross-sections and can be activated deep in the NIR (ca. 780-850 nm). These porphyrins can be incorporated into a therapeutic triad that also employs an small molecule targeting agent that directs the triad to over-expressed tumor receptor sites, and a NIR onephoton imaging agent that allows tracking the delivery of the triad to the tumor site, as well as clearance of excess triad from healthy tissue prior to the start of PDT treatment. We are currently using these new triads in efficacy studies with a breast cancer cell line that has been transfected with luciferase genes that allow implanted tumor growth and post- PDT treatment efficacy studies in SCID mouse models by following the rise and decay of the bioluminescence signal. We have also designed highly absorbing and scattering collagen breast cancer phantoms in which we have demonstrated

  20. Analysis of the Purcell effect in photonic and plasmonic crystals with losses.

    Science.gov (United States)

    Iwase, Hideo; Englund, Dirk; Vucković, Jelena

    2010-08-02

    We study the spontaneous emission rate of emitter in a periodically patterned metal or dielectric membrane in the picture of a multimode field of damped Bloch states. For Bloch states in dielectric structures, the approach fully describes the Purcell effect in photonic crystal or spatially coupled cavities with losses. For a metal membrane, the Purcell factor depends on resistive loss at the resonant frequency of surface plasmon polariton (SPP). Analysis of an InP-Au-InP structure indicates that the SPP's Purcell effect can exceed a value of 50 in the ultraviolet. For a plasmonic crystal, we find a position-dependent Purcell enhancement with a mean value similar to the unpatterned membrane.

  1. A Cascaded Incoherent Spectrum Sliced Transversal Photonic Microwave Filters-An Analysis

    Directory of Open Access Journals (Sweden)

    R. K. Jeyachitra

    2010-05-01

    Full Text Available An analysis of the performance of a simple, incoherent spectrum sliced microwave photonic filter is presented. This filter structure is based on cascading of two incoherent fiber Fabry -Pérot filters as a slicing element of a broadband optical source. The filter performance is studied by measuring the overall Free Spectral Range, 3dB Bandwidth, Quality factor and Main Lobe to Sidelobe Suppression level for different modes of connecting the filter in cascadedconfiguration. Also simulation results are presented. The Characteristics of cascaded FP filters with different configurations are tabulated. The estimated performances show that this cascaded filter combination can be tuned over the frequency from 4.6GHz to 18 GHz with very good sidelobe suppression level.

  2. gPhoton: The GALEX Photon Data Archive

    Science.gov (United States)

    Million, Chase; Fleming, Scott W.; Shiao, Bernie; Seibert, Mark; Loyd, Parke; Tucker, Michael; Smith, Myron; Thompson, Randy; White, Richard L.

    2016-12-01

    gPhoton is a new database product and software package that enables analysis of GALEX ultraviolet data at the photon level. The project’s stand-alone, pure-Python calibration pipeline reproduces the functionality of the original mission pipeline to reduce raw spacecraft data to lists of time-tagged, sky-projected photons, which are then hosted in a publicly available database by the Mikulski Archive at Space Telescope. This database contains approximately 130 terabytes of data describing approximately 1.1 trillion sky-projected events with a timestamp resolution of five milliseconds. A handful of Python and command-line modules serve as a front end to interact with the database and to generate calibrated light curves and images from the photon-level data at user-defined temporal and spatial scales. The gPhoton software and source code are in active development and publicly available under a permissive license. We describe the motivation, design, and implementation of the calibration pipeline, database, and tools, with emphasis on divergence from prior work, as well as challenges created by the large data volume. We summarize the astrometric and photometric performance of gPhoton relative to the original mission pipeline. For a brief example of short time-domain science capabilities enabled by gPhoton, we show new flares from the known M-dwarf flare star CR Draconis. The gPhoton software has permanent object identifiers with the ASCL (ascl:1603.004) and DOI (doi:10.17909/T9CC7G). This paper describes the software as of version v1.27.2.

  3. Broadband photon time of flight spectroscopy: advanced spectroscopic analysis for ensuring safety and performance of pharmaceutical tablets

    DEFF Research Database (Denmark)

    Kamran, Faisal; Nielsen, Otto Højager Attermann; Andersson-Engels, Stefan;

    2013-01-01

    We report on extended spectroscopic analysis of pharmaceutical tablets performed with broadband photon time-of-flight absorption/scaring spectroscopy. Precise monitoring of absorption and scattering spectra enables cost-efficient monitoring of key safety and performance parameters of the drugs....

  4. A Raman cell based on hollow core photonic crystal fiber for human breath analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Kam Kong; Zeng, Haishan, E-mail: hzeng@bccrc.ca [Imaging Unit – Integrative Oncology Department, British Columbia Cancer Agency Research Centre, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada and Medical Physics Program – Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia V6T 1Z1 (Canada); Short, Michael; Lam, Stephen; McWilliams, Annette [Imaging Unit – Integrative Oncology Department, British Columbia Cancer Agency Research Centre, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3 (Canada)

    2014-09-15

    Purpose: Breath analysis has a potential prospect to benefit the medical field based on its perceived advantages to become a point-of-care, easy to use, and cost-effective technology. Early studies done by mass spectrometry show that volatile organic compounds from human breath can represent certain disease states of our bodies, such as lung cancer, and revealed the potential of breath analysis. But mass spectrometry is costly and has slow-turnaround time. The authors’ goal is to develop a more portable and cost effective device based on Raman spectroscopy and hollow core-photonic crystal fiber (HC-PCF) for breath analysis. Methods: Raman scattering is a photon-molecular interaction based on the kinetic modes of an analyte which offers unique fingerprint type signals that allow molecular identification. HC-PCF is a novel light guide which allows light to be confined in a hollow core and it can be filled with a gaseous sample. Raman signals generated by the gaseous sample (i.e., human breath) can be guided and collected effectively for spectral analysis. Results: A Raman-cell based on HC-PCF in the near infrared wavelength range was developed and tested in a single pass forward-scattering mode for different gaseous samples. Raman spectra were obtained successfully from reference gases (hydrogen, oxygen, carbon dioxide gases), ambient air, and a human breath sample. The calculated minimum detectable concentration of this system was ∼15 parts per million by volume, determined by measuring the carbon dioxide concentration in ambient air via the characteristic Raman peaks at 1286 and 1388 cm{sup −1}. Conclusions: The results of this study were compared to a previous study using HC-PCF to trap industrial gases and backward-scatter 514.5 nm light from them. The authors found that the method presented in this paper has an advantage to enhance the signal-to-noise ratio (SNR). This SNR advantage, coupled with the better transmission of HC-PCF in the near-IR than in the

  5. Photo-redox activated drug delivery systems operating under two photon excitation in the near-IR.

    Science.gov (United States)

    Guardado-Alvarez, Tania M; Devi, Lekshmi Sudha; Vabre, Jean-Marie; Pecorelli, Travis A; Schwartz, Benjamin J; Durand, Jean-Olivier; Mongin, Olivier; Blanchard-Desce, Mireille; Zink, Jeffrey I

    2014-05-07

    We report the design and synthesis of a nano-container consisting of mesoporous silica nanoparticles with the pore openings covered by "snap-top" caps that are opened by near-IR light. A photo transducer molecule that is a reducing agent in an excited electronic state is covalently attached to the system. Near IR two-photon excitation causes inter-molecular electron transfer that reduces a disulfide bond holding the cap in place, thus allowing the cargo molecules to escape. We describe the operation of the "snap-top" release mechanism by both one- and two-photon activation. This system presents a proof of concept of a near-IR photoredox-induced nanoparticle delivery system that may lead to a new type of photodynamic drug release therapy.

  6. Design and analysis of polarization independent all-optical logic gates in silicon-on-insulator photonic crystal

    Science.gov (United States)

    Rani, Preeti; Kalra, Yogita; Sinha, R. K.

    2016-09-01

    In this paper, we have reported design and analysis of polarization independent all optical logic gates in silicon-on-insulator photonic crystal consisting of two dimensional honeycomb lattices with two different air holes exhibiting photonic band gap for both TE and TM mode in the optical communication window. The proposed structures perform as an AND optical logic gate and all the optical logic gates based on the phenomenon of interference. The response period and bit rate for TE and TM polarizations at a wavelength of 1.55 μm show improved results as reported earlier.

  7. Analysis of strictly bound modes in photonic crystal fibers by use of a source-model technique.

    Science.gov (United States)

    Hochman, Amit; Leviatan, Yehuda

    2004-06-01

    We describe a source-model technique for the analysis of the strictly bound modes propagating in photonic crystal fibers that have a finite photonic bandgap crystal cladding and are surrounded by an air jacket. In this model the field is simulated by a superposition of fields of fictitious electric and magnetic current filaments, suitably placed near the media interfaces of the fiber. A simple point-matching procedure is subsequently used to enforce the continuity conditions across the interfaces, leading to a homogeneous matrix equation. Nontrivial solutions to this equation yield the mode field patterns and propagation constants. As an example, we analyze a hollow-core photonic crystal fiber. Symmetry characteristics of the modes are discussed and exploited to reduce the computational burden.

  8. Neuromorphic Silicon Photonics

    CERN Document Server

    Tait, Alexander N; de Lima, Thomas Ferreira; Wu, Allie X; Nahmias, Mitchell A; Shastri, Bhavin J; Prucnal, Paul R

    2016-01-01

    We report first observations of an integrated analog photonic network, in which connections are configured by microring weight banks, as well as the first use of electro-optic modulators as photonic neurons. A mathematical isomorphism between the silicon photonic circuit and a continuous neural model is demonstrated through dynamical bifurcation analysis. Exploiting this isomorphism, existing neural engineering tools can be adapted to silicon photonic information processing systems. A 49-node silicon photonic neural network programmed using a "neural compiler" is simulated and predicted to outperform a conventional approach 1,960-fold in a toy differential system emulation task. Photonic neural networks leveraging silicon photonic platforms could access new regimes of ultrafast information processing for radio, control, and scientific computing.

  9. A Three-Photon Active Organic Fluorophore for Deep Tissue Ratiometric Imaging of Intracellular Divalent Zinc.

    Science.gov (United States)

    Philips, Divya Susan; Sreejith, Sivaramapanicker; He, Tingchao; Menon, Nishanth Venugopal; Anees, Palapuravan; Mathew, Jomon; Sajikumar, Sreedharan; Kang, Yuejun; Stuparu, Mihaiela Corina; Sun, Handong; Zhao, Yanli; Ajayaghosh, Ayyappanpillai

    2016-05-20

    Deep tissue bioimaging with three-photon (3P) excitation using near-infrared (NIR) light in the second IR window (1.0-1.4 μm) could provide high resolution images with an improved signal-to-noise ratio. Herein, we report a photostable and nontoxic 3P excitable donor-π-acceptor system (GMP) having 3P cross-section (σ3 ) of 1.78×10(-80)  cm(6)  s(2)  photon(-2) and action cross-section (σ3 η3 ) of 2.31×10(-81)  cm(6)  s(2)  photon(-2) , which provides ratiometric fluorescence response with divalent zinc ions in aqueous conditions. The probe signals the Zn(2+) binding at 530 and 600 nm, respectively, upon 1150 nm excitation with enhanced σ3 of 1.85×10(-80)  cm(6)  s(2)  photon(-2) and σ3 η3 of 3.33×10(-81)  cm(6)  s(2)  photon(-2) . The application of this probe is demonstrated for ratiometric 3P imaging of Zn(2+) in vitro using HuH-7 cell lines. Furthermore, the Zn(2+) concentration in rat hippocampal slices was imaged at 1150 nm excitation after incubation with GMP, illustrating its potential as a 3P ratiometric probe for deep tissue Zn(2+) ion imaging.

  10. Photonic homeostatics

    Science.gov (United States)

    Liu, Timon C.; Li, Fan-Hui

    2010-11-01

    Photonic homeostatics is a discipline to study the establishment, maintenance, decay, upgrading and representation of function-specific homoestasis (FSH) by using photonics. FSH is a negative-feedback response of a biosystem to maintain the function-specific fluctuations inside the biosystem so that the function is perfectly performed. A stress may increase sirtuin 1 (SIRT1) activities above FSH-specific SIRT1 activity to induce a function far from its FSH. On the one hand, low level laser irradiation or monochromatic light (LLL) can not modulate a function in its FSH or a stress in its stress-specific homeostasis (StSH), but modulate a function far from its FSH or a stress far from its StSH. On the other hand, the biophotons from a biosystem with its function in its FSH should be less than the one from the biosystem with its function far from its FSH. The non-resonant interaction of low intensity laser irradiation or monochromatic light (LIL) and a kind of membrane protein can be amplified by all the membrane proteins if the function is far from its FSH. This amplification might hold for biophoton emission of the membrane protein so that the photonic spectroscopy can be used to represent the function far from its FSH, which is called photonomics.

  11. Photon-photon collisions

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J.

    1985-01-01

    The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of ..cap alpha../sub s/ and ..lambda../sup ms/ from the ..gamma..*..gamma.. ..-->.. ..pi../sup 0/ form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from ..gamma gamma.. ..-->.. H anti H, reconstruction of sigma/sub ..gamma gamma../ from exclusive channels at low W/sub ..gamma gamma../, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z/sup 0/ and W/sup + -/ beams from e ..-->.. eZ/sup 0/ and e ..-->.. nu W will become important. 44 references.

  12. Analysis of Precision of Activation Analysis Method

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Nørgaard, K.

    1973-01-01

    The precision of an activation-analysis method prescribes the estimation of the precision of a single analytical result. The adequacy of these estimates to account for the observed variation between duplicate results from the analysis of different samples and materials, is tested by the statistic T......, which is shown to be approximated by a χ2 distribution. Application of this test to the results of determinations of manganese in human serum by a method of established precision, led to the detection of airborne pollution of the serum during the sampling process. The subsequent improvement in sampling...... conditions was shown to give not only increased precision, but also improved accuracy of the results....

  13. Numerical Methods for the Design and Analysis of Photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Roberts, John

    2008-01-01

    The numerical methods available for calculating the electromagnetic mode properties of photonic crystal fibres are reviewed. The preferred schemes for analyzing TIR guiding and band gap guiding fibres are contrasted.......The numerical methods available for calculating the electromagnetic mode properties of photonic crystal fibres are reviewed. The preferred schemes for analyzing TIR guiding and band gap guiding fibres are contrasted....

  14. New design strategy for the two-photon active material based on push-pull substituted bisanthene molecule.

    Science.gov (United States)

    Chattopadhyaya, Mausumi; Alam, Md Mehboob; Chakrabarti, Swapan

    2011-03-31

    In the present work, we have critically examined the origin of strong two-photon transition probability of a donor-acceptor substituted bisanthene molecule that imitates a small piece of edge passivated (4, 4) graphene nanoribbon. In our calculations, we have considered -OMe, and -NH(2) as donors and -NO(2) as an acceptor. The one- and two-photon absorption parameters are evaluated using state-of-the-art linear and quadratic response theory, respectively, and all these calculations are carried out within the framework of time dependent density functional theory. To give a proper judgment on our findings, we have used the long-range corrected CAMB3LYP functional for all of the time dependent calculations. The present investigation reveals that the bisanthene molecule with three pairs of donor/acceptor moiety has a lower two-photon transition probability than that of a suitably designed bisanthene with only a single pair of donor/acceptor moiety. This in silico observation is consistent for all of the donor/acceptor moieties chosen in the present work. A comprehensive analysis at the two state model level of theory clearly offers us a verdict that by placing the donor/acceptor moiety in a suitable position of bisanthene, we can create a significant asymmetry in the electron density in the first excited state, which eventually leads to a significant difference in the ground and excited state dipole moment and is attributed to the higher two-photon transition probability of a particular bisanthene with a single pair of donor/acceptor moiety than bisanthene with three pairs of donor/acceptor.

  15. Elemental Analysis of Nanomaterial Using Photon-Atom Interaction Based EDXRF Technique

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar

    2013-08-01

    Full Text Available Presence of trace amount of foreign impurities (both metallic and non-metallic in standard salts used for sample preparation and during the synthesis process can alter the physical and chemical behavior of the pure and doped nano-materials. Therefore, it becomes important to determine concentration of various elements present in synthesized nano-material sample. In present work, the elemental and compositional analysis of nano-materials synthesized using various methods has been performed using photon-atom interaction based energy dispersive x-ray fluorescence (EDXRF technique. This technique due to its multielement analytical capability, lower detection limit, capability to analyze metals and non-metals alike and almost no sample preparation requirements can be utilized for analysis of nano-materials. The EDXRF spectrometer involves a 2.4 kW Mo anode x-ray tube (Pananalytic, Netherland equipped with selective absorbers as an excitation source and an LEGe detector (FWHM = 150 eV at 5.895 keV, Canberra, US coupled with PC based multichannel analyzer used to collect the fluorescentx-ray spectra. The analytical results showed good agreements with the expected values calculated on the basis of the precursor used in preparation of nano-materials.

  16. Segmentation, Reconstruction, and Analysis of Blood Thrombus Formation in 3D 2-Photon Microscopy Images

    Directory of Open Access Journals (Sweden)

    Xu Zhiliang

    2010-01-01

    Full Text Available We study the problem of segmenting, reconstructing, and analyzing the structure growth of thrombi (clots in blood vessels in vivo based on 2-photon microscopic image data. First, we develop an algorithm for segmenting clots in 3D microscopic images based on density-based clustering and methods for dealing with imaging artifacts. Next, we apply the union-of-balls (or alpha-shape algorithm to reconstruct the boundary of clots in 3D. Finally, we perform experimental studies and analysis on the reconstructed clots and obtain quantitative data of thrombus growth and structures. We conduct experiments on laser-induced injuries in vessels of two types of mice (the wild type and the type with low levels of coagulation factor VII and analyze and compare the developing clot structures based on their reconstructed clots from image data. The results we obtain are of biomedical significance. Our quantitative analysis of the clot composition leads to better understanding of the thrombus development, and is valuable to the modeling and verification of computational simulation of thrombogenesis.

  17. Two-photon imaging of neural activity and structural plasticity in the rodent spinal cord

    OpenAIRE

    Johannssen, H

    2011-01-01

    In my PhD thesis, I used two‐photon imaging to investigate neuronal circuits and glia cells in the spinal cord of living mice. To achieve this, a major effort first was to establish a mouse spinal cord preparation suitable for stable and long‐lasting imaging experiments. Without adequate stabilisation, the spinal cord was prone to large‐scale movement artefacts clearly hampering high‐resolution imaging in vivo. To overcome these limitations, I employed strategies to optimise th...

  18. Photons to axion-like particles conversion in Active Galactic Nuclei

    Directory of Open Access Journals (Sweden)

    Fabrizio Tavecchio

    2015-05-01

    Full Text Available The idea that photons can convert to axion-like particles (ALPs γ→a in or around an AGN and reconvert back to photons a→γ in the Milky Way magnetic field has been put forward in 2008 and has recently attracted growing interest. Yet, so far nobody has estimated the conversion probability γ→a as carefully as allowed by present-day knowledge. Our aim is to fill this gap. We first remark that AGN which can be detected above 100 GeV are blazars, namely AGN with jets, with one of them pointing towards us. Moreover, blazars fall into two well defined classes: BL Lac objects (BL Lacs and Flat Spectrum Radio Quasars (FSRQs, with drastically different properties. In this Letter we report a preliminary evaluation of the γ→a conversion probability inside these two classes of blazars. Our findings are surprising. Indeed, while in the case of BL Lacs the conversion probability turns out to be totally unpredictable due to the strong dependence on the values of the somewhat uncertain position of the emission region along the jet and strength of the magnetic field therein, for FSRQs we are able to make a clear-cut prediction. Our results are of paramount importance in view of the planned very-high-energy photon detectors like the CTA, HAWK, GAMMA-400 and HISCORE.

  19. Single and few photon avalanche photodiode detection process study

    Science.gov (United States)

    Blazej, Josef; Prochazka, Ivan

    2009-07-01

    We are presenting the results of the study of the Single Photon Avalanche Diode (SPAD) pulse response risetime and its dependence on several key parameters. We were investigating the unique properties of K14 type SPAD with its high delay uniformity of 200 μm active area and the correlation between the avalanche buildup time and the photon number involved in the avalanche trigger. The detection chip was operated in a passive quenching circuit with active gating. This setup enabled us to monitor the diode reverse current using an electrometer, a fast digitizing oscilloscope, and using a custom design comparator circuit. The electrometer reading enabled to estimate the photon number per detection event, independently on avalanche process. The avalanche build up was recorded on the oscilloscope and processed by custom designed waveform analysis package. The correlation of avalanche build up to the photon number, bias above break, photon absorption location, optical pulse length and photon energy was investigated in detail. The experimental results are presented. The existing solid state photon counting detectors have been dedicated for picosecond resolution and timing stability of single photon events. However, the high timing stability is maintained for individual single photons detection, only. If more than one photon is absorbed within the detector time resolution, the detection delay will be significantly affected. This fact is restricting the application of the solid state photon counters to cases where single photons may be guaranteed, only. For laser ranging purposes it is highly desirable to have a detector, which detects both single photon and multi photon signals with picoseconds stability. The SPAD based photon counter works in a purely digital mode: a uniform output signal is generated once the photon is detected. If the input signal consists of several photons, the first absorbed one triggers the avalanche. Obviously, for multiple photon signals, the

  20. gPhoton: The GALEX Photon Data Archive

    CERN Document Server

    Million, Chase; Shiao, Bernie; Seibert, Mark; Loyd, Parke; Tucker, Michael; Smith, Myron; Thompson, Randy; White, Richard L

    2016-01-01

    gPhoton is a new database product and software package that enables analysis of GALEX ultraviolet data at the photon level. The project's stand-alone, pure-Python calibration pipeline reproduces the functionality of the original mission pipeline to reduce raw spacecraft data to lists of time-tagged, sky-projected photons, which are then hosted in a publicly available database by the Mikulski Archive at Space Telescope (MAST). This database contains approximately 130 terabytes of data describing approximately 1.1 trillion sky-projected events with a timestamp resolution of five milliseconds. A handful of Python and command line modules serve as a front-end to interact with the database and to generate calibrated light curves and images from the photon-level data at user-defined temporal and spatial scales. The gPhoton software and source code are in active development and publicly available under a permissive license. We describe the motivation, design, and implementation of the calibration pipeline, database,...

  1. Towards a methodology for large-sample prompt-gamma neutron-activation analysis

    NARCIS (Netherlands)

    Degenaar, I.H.

    2004-01-01

    Large-sample prompt-gamma neutron-activation analysis, or shortly LS PGNAA, is a method by which mass fractions of elements can be determined in large samples with a mass over 1 kg. In this method the large sample is irradiated with neutrons. Directly (prompt) after absorption of the neutrons photon

  2. Photon wave function formalism for analysis of Mach–Zehnder interferometer and sum-frequency generation

    Energy Technology Data Exchange (ETDEWEB)

    Ritboon, Atirach, E-mail: atirach.3.14@gmail.com [School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ (United Kingdom); Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai 90112 (Thailand); Daengngam, Chalongrat, E-mail: chalongrat.d@psu.ac.th [Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai 90112 (Thailand); Pengpan, Teparksorn, E-mail: teparksorn.p@psu.ac.th [Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai 90112 (Thailand)

    2016-08-15

    Biakynicki-Birula introduced a photon wave function similar to the matter wave function that satisfies the Schrödinger equation. Its second quantization form can be applied to investigate nonlinear optics at nearly full quantum level. In this paper, we applied the photon wave function formalism to analyze both linear optical processes in the well-known Mach–Zehnder interferometer and nonlinear optical processes for sum-frequency generation in dispersive and lossless medium. Results by photon wave function formalism agree with the well-established Maxwell treatments and existing experimental verifications.

  3. Analysis of two-dimensional photonic band gap structure with a rhombus lattice

    Institute of Scientific and Technical Information of China (English)

    Limei Qi; Ziqiang Yang; Xi Gao; Zheng Liang

    2008-01-01

    @@ The relative band gap for a rhombus lattice photonic crystal is studied by plane wave expansion method and high frequency structure simulator (HFSS) simulation. General wave vectors in the first Briliouin zone are derived. The relative band gap as a function of air-filling factor and background material is investigated, respectively, and the nature of photonic band gap for different lattice angles is analyzed by the distribution of electric energy. These results would provide theoretical instruction for designing optical integrated devices using photonic crystal with a rhombus lattice.

  4. Simulating single photons with realistic photon sources

    Science.gov (United States)

    Yuan, Xiao; Zhang, Zhen; Lütkenhaus, Norbert; Ma, Xiongfeng

    2016-12-01

    Quantum information processing provides remarkable advantages over its classical counterpart. Quantum optical systems have been proved to be sufficient for realizing general quantum tasks, which, however, often rely on single-photon sources. In practice, imperfect single-photon sources, such as a weak-coherent-state source, are used instead, which will inevitably limit the power in demonstrating quantum effects. For instance, with imperfect photon sources, the key rate of the Bennett-Brassard 1984 (BB84) quantum key distribution protocol will be very low, which fortunately can be resolved by utilizing the decoy-state method. As a generalization, we investigate an efficient way to simulate single photons with imperfect ones to an arbitrary desired accuracy when the number of photonic inputs is small. Based on this simulator, we can thus replace the tasks that involve only a few single-photon inputs with the ones that make use of only imperfect photon sources. In addition, our method also provides a quantum simulator to quantum computation based on quantum optics. In the main context, we take a phase-randomized coherent state as an example for analysis. A general photon source applies similarly and may provide some further advantages for certain tasks.

  5. RADSAT Benchmarks for Prompt Gamma Neutron Activation Analysis Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Kimberly A.; Gesh, Christopher J.

    2011-07-01

    The accurate and efficient simulation of coupled neutron-photon problems is necessary for several important radiation detection applications. Examples include the detection of nuclear threats concealed in cargo containers and prompt gamma neutron activation analysis for nondestructive determination of elemental composition of unknown samples. High-resolution gamma-ray spectrometers are used in these applications to measure the spectrum of the emitted photon flux, which consists of both continuum and characteristic gamma rays with discrete energies. Monte Carlo transport is the most commonly used simulation tool for this type of problem, but computational times can be prohibitively long. This work explores the use of multi-group deterministic methods for the simulation of coupled neutron-photon problems. The main purpose of this work is to benchmark several problems modeled with RADSAT and MCNP to experimental data. Additionally, the cross section libraries for RADSAT are updated to include ENDF/B-VII cross sections. Preliminary findings show promising results when compared to MCNP and experimental data, but also areas where additional inquiry and testing are needed. The potential benefits and shortcomings of the multi-group-based approach are discussed in terms of accuracy and computational efficiency.

  6. Design, analysis, and transmission system performance of a 41 GHz silicon photonic modulator.

    Science.gov (United States)

    Patel, David; Ghosh, Samir; Chagnon, Mathieu; Samani, Alireza; Veerasubramanian, Venkat; Osman, Mohamed; Plant, David V

    2015-06-01

    The design and characterization of a slow-wave series push-pull traveling wave silicon photonic modulator is presented. At 2 V and 4 V reverse bias, the measured -3 dB electro-optic bandwidth of the modulator with an active length of 4 mm are 38 GHz and 41 GHz, respectively. Open eye diagrams are observed up to bitrates of 60 Gbps without any form of signal processing, and up to 70 Gbps with passive signal processing to compensate for the test equipment. With the use of multi-level amplitude modulation formats and digital-signal-processing, the modulator is shown to operate below a hard-decision forward error-correction threshold of 3.8×10-3 at bitrates up to 112 Gbps over 2 km of single mode optical fiber using PAM-4, and over 5 km of optical fiber with PAM-8. Energy consumed solely by the modulator is also estimated for different modulation cases.

  7. Design and analysis of a photonic crystal fiber based polarization filter using surface plasmon resonance

    Science.gov (United States)

    Yogalakshmi, S.; Selvendran, S.; Sivanantha Raja, A.

    2016-05-01

    A photonic crystal fiber with an active metal nanowire is proposed to act as a polarization filter based on the principle of plasmonic resonance. The light launched into the silica core gets coupled to gold wire inducing surface plasmon resonance, filtering one of the two orthogonally polarized light waves in the third optical communication window. This polarization filtering characteristic is analyzed using the finite element method. The change in the performance behaviour of the proposed filter is investigated by increasing the number of embedded gold wires, altering their positions and varying the diameter of gold wire. It is found that enhanced absorption of the core guided mode is achieved by replacing the filled metal nanowire with a metal coating around the air hole. Filtering of any or both polarizations can be attained by suitably positioning the metal wires. Confinement loss as high as 348.55 and 302 dB cm-1 for y-polarized and x-polarized lights respectively are attained at 1.52 and 1.56 μm respectively for single gold wire. The filter acts as a single polarization filter filtering x-polarized light with a confinement loss value of 187.67 dB cm-1 when two gold nanowires are placed adjacently. The same structure acts as the filter for y-polarized light by employing gold coating exhibiting an increased confinement loss of 406.34 dB cm-1 at 1.64 μm.

  8. Two-Photon Polarization Dependent Spectroscopy in Chirality: A Novel Experimental-Theoretical Approach to Study Optically Active Systems

    Directory of Open Access Journals (Sweden)

    Florencio E. Hernández

    2011-04-01

    Full Text Available Many phenomena, including life itself and its biochemical foundations are fundamentally rooted in chirality. Combinatorial methodologies for catalyst discovery and optimization remain an invaluable tool for gaining access to enantiomerically pure compounds in the development of pharmaceuticals, agrochemicals, and flavors. Some exotic metamaterials exhibiting negative refractive index at optical frequencies are based on chiral structures. Chiroptical activity is commonly quantified in terms of circular dichroism (CD and optical rotatory dispersion (ORD. However, the linear nature of these effects limits their application in the far and near-UV region in highly absorbing and scattering biological systems. In order to surmount this barrier, in recent years we made important advancements on a novel non linear, low-scatter, long-wavelength CD approach called two-photon absorption circular dichroism (TPACD. Herein we present a descriptive analysis of the optics principles behind the experimental measurement of TPACD, i.e., the double L-scan technique, and its significance using pulsed lasers. We also make an instructive examination and discuss the reliability of our theoretical-computational approach, which uses modern analytical response theory, within a Time-Dependent Density Functional Theory (TD-DFT approach. In order to illustrate the potential of this novel spectroscopic tool, we first present the experimental and theoretical results obtained in C2-symmetric, axially chiral R-(+-1,1'-bi(2-naphthol, R-BINOL, a molecule studied at the beginning of our investigation in this field. Next, we reveal some preliminary results obtained for (R-3,3′-diphenyl-2,2′-bi-1-naphthol, R-VANOL, and (R-2,2′-diphenyl-3,3′-(4-biphenanthrol, R-VAPOL. This family of optically active compounds has been proven to be a suitable model for the structure-property relationship study of TPACD, because its members are highly conjugated yet photo-stable, and easily

  9. Two-photon polarization dependent spectroscopy in chirality: a novel experimental-theoretical approach to study optically active systems.

    Science.gov (United States)

    Hernández, Florencio E; Rizzo, Antonio

    2011-04-18

    Many phenomena, including life itself and its biochemical foundations are fundamentally rooted in chirality. Combinatorial methodologies for catalyst discovery and optimization remain an invaluable tool for gaining access to enantiomerically pure compounds in the development of pharmaceuticals, agrochemicals, and flavors. Some exotic metamaterials exhibiting negative refractive index at optical frequencies are based on chiral structures. Chiroptical activity is commonly quantified in terms of circular dichroism (CD) and optical rotatory dispersion (ORD). However, the linear nature of these effects limits their application in the far and near-UV region in highly absorbing and scattering biological systems. In order to surmount this barrier, in recent years we made important advancements on a novel non linear, low-scatter, long-wavelength CD approach called two-photon absorption circular dichroism (TPACD). Herein we present a descriptive analysis of the optics principles behind the experimental measurement of TPACD, i.e., the double L-scan technique, and its significance using pulsed lasers. We also make an instructive examination and discuss the reliability of our theoretical-computational approach, which uses modern analytical response theory, within a Time-Dependent Density Functional Theory (TD-DFT) approach. In order to illustrate the potential of this novel spectroscopic tool, we first present the experimental and theoretical results obtained in C(2)-symmetric, axially chiral R-(+)-1,1'-bi(2-naphthol), R-BINOL, a molecule studied at the beginning of our investigation in this field. Next, we reveal some preliminary results obtained for (R)-3,3'-diphenyl-2,2'-bi-1-naphthol, R-VANOL, and (R)-2,2'-diphenyl-3,3'-(4-biphenanthrol), R-VAPOL. This family of optically active compounds has been proven to be a suitable model for the structure-property relationship study of TPACD, because its members are highly conjugated yet photo-stable, and easily derivatized at the 5

  10. Comprehensive analysis of photonic nanojets in 3D dielectric cuboids excited by surface plasmons

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco-Pena, Victor [Antennas Group - TERALAB, Universidad Publica de Navarra, Campus Arrosadia, 31006, Pamplona (Spain); Minin, Igor V.; Minin, Oleg V. [National Research Tomsk State University, Lenina Ave., 36, Tomsk, 634050 (Russian Federation); Beruete, Miguel [Antennas Group - TERALAB, Universidad Publica de Navarra, Campus Arrosadia, 31006, Pamplona (Spain); Institute of Smart Cities, Public University of Navarra, 31006, Pamplona (Spain)

    2016-10-15

    In this paper we study the excitation of photonic nanojets (PNJ) in 3D dielectric cuboids by surface plasmons at telecommunication wavelengths. The analysis is done using the effective refractive index approach. It is shown that the refractive index contrast between the regions with and without cuboid should be roughly less than 2 in order to generate jets at the output of the cuboid. The best performance at λ{sub 0} = 1550 nm is obtained when the height of the cuboid is 160 nm producing a jet just at the output interface with a subwavelength resolution of 0.68λ{sub 0} and a high intensity enhancement (x 5) at the focus. The multi-wavelength response is also studied demonstrating that it is possible to use the proposed structure at different wavelengths. Finally, the backscattering enhancement is numerically evaluated by inserting a metal particle within the PNJ region, demonstrating a maximum value of ∝2.44 dB for a gold sphere of radius 0.1λ{sub 0}. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Determination of single photon ionization cross sections for quantitative analysis of complex organic mixtures.

    Science.gov (United States)

    Adam, Thomas; Zimmermann, Ralf

    2007-11-01

    Soft single photon ionization (SPI)-time-of-flight mass spectrometry (TOFMS) is well suited for fast and comprehensive analysis of complex organic gas mixtures, which has been demonstrated in various applications. This work describes a calibration scheme for SPI, which enables quantification of a large number of compounds by only calibrating one compound of choice, in this case benzene. Photoionization cross sections of 22 substances were determined and related to the yield of benzene. These substances included six alkanes (pentane, hexane, heptane, octane, nonane, decane), three alkenes (propene, butane, pentene), two alkynes (propyne, butyne), two dienes (butadiene, isoprene), five monoaromatic species (benzene, toluene, xylene, styrene, monochlorobenzene) and NO. The cross sections of organic compounds differ by about one order of magnitude but the photoionization properties of compounds belonging to one compound class are rather similar. Therefore, the scheme can also be used for an approximate quantification of compound classes. This is demonstrated by a fast characterization and pattern recognition of two gasoline samples with different origins (Germany and South Africa) and a diesel sample (Germany). The on-line capability of the technique and the scheme is demonstrated by quantitatively monitoring and comparing the cold engine start of four vehicles: a gasoline passenger car, a diesel van, a motorbike and a two-stroke scooter.

  12. Photonic circuit for high order USB and LSB separation for remote heterodyning: analysis and simulation.

    Science.gov (United States)

    Hasan, Mehedi; Hall, Trevor J

    2015-09-21

    A novel photonic integrated circuit is proposed that, using an RF source, generates at its output ports the same magnitude but opposite sign high order single optical side bands of a suppressed optical carrier. A single stage parallel Mach-Zehnder Modulator (MZM) and a two-stage series parallel MZM architecture are described and their relative merits discussed. A transfer matrix method is used to describe the operation of the circuits. The theoretical analysis is validated by computer simulation. As an illustration of a prospective application, it is shown how the circuit may be used as a key element of an optical transmission system to transport radio signals over fibre for wireless access; generating remotely a mm-wave carrier modulated by digital IQ data. A detailed calculation of symbol error rate is presented to characterise the system performance. The circuit may be fabricated in any integration platform offering a suitable phase modulator circuit element such as LiNbO(3), Silicon, and III-V or hybrid technology.

  13. Radiometric Short-Term Fourier Transform analysis of photonic Doppler velocimetry recordings and detectivity limit

    Science.gov (United States)

    Prudhomme, G.; Berthe, L.; Bénier, J.; Bozier, O.; Mercier, P.

    2017-01-01

    Photonic Doppler Velocimetry is a plug-and-play and versatile diagnostic used in dynamic physic experiments to measure velocities. When signals are analyzed using a Short-Time Fourier Transform, multiple velocities can be distinguished: for example, the velocities of moving particle-cloud appear on spectrograms. In order to estimate the back-scattering fluxes of target, we propose an original approach "PDV Radiometric analysis" resulting in an expression of time-velocity spectrograms coded in power units. Experiments involving micron-sized particles raise the issue of detection limit; particle-size limit is very difficult to evaluate. From the quantification of noise sources, we derive an estimation of the spectrogram noise leading to a detectivity limit, which may be compared to the fraction of the incoming power which has been back-scattered by the particle and then collected by the probe. This fraction increases with their size. At last, some results from laser-shock accelerated particles using two different PDV systems are compared: it shows the improvement of detectivity with respect to the Effective Number of Bits (ENOB) of the digitizer.

  14. Generation and analysis of correlated pairs of photons on board a nanosatellite

    CERN Document Server

    Tang, Zhongkan; Tan, Yue Chuan; Cheng, Cliff; Sha, Luo; Hiang, Goh Cher; Oi, Daniel; Ling, Alexander

    2016-01-01

    Satellites carrying sources of entangled photons could establish a global quantum network, enabling private encryption keys between any two points on Earth. Despite numerous proposals, demonstration of space-based quantum systems has been limited due to the cost of traditional satellites. We are using very small spacecraft to accelerate progress. We report the in-orbit operation of a photon pair source aboard a 1.65 kg nanosatellite and demonstrate pair generation and polarization correlation under space conditions. The in-orbit photon correlations exhibit a contrast of 97+/-2%, matching ground-based tests. This pathfinding mission overcomes the challenge of demonstrating in-orbit performance for the components of future entangled photon experiments. Ongoing operation establishes the in-orbit lifetime of these critical components. More generally, this demonstrates the ability for nanosatellites to enable faster progress in space-based research.

  15. Design and Analysis of Microstrip Multi-Channeled Filter Using Photonic Crystal Branchy Defect

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A multi-channeled filter based on branchy defect in a microstrip photonic crystal was proposed. By introducing a branchy structure across the defect region, multiple defect modes will appear inside the photonic gap, leading to the multi-channeled filtering phenomenon. In comparison with the conventional multi-channeled filters, the proposed structure is more compact and tunable as far as the device volume and fabrication are concerned. The microwave experiment results are found in agreement with simulation results.

  16. Activation of silicon quantum dots and coupling between the active centre and the defect state of the photonic crystal in a nanolaser

    Institute of Scientific and Technical Information of China (English)

    Huang Wei-Qi; Chen Hang-Qiong; Shu Qin; Liu Shi-Rong; Qin Chao-Jian

    2012-01-01

    A new nanolaser concept using silicon quantum dots (QDs) is proposed.The conduction band opened by the quantum confinement effect gives the pumping levels.Localized states in the gap due to some surface bonds on Si QDs can be formed for the activation of emission.An inversion of population can be generated between the localized states and the valence band in a QD fabricated by using a nanosecond pulse laser.Coupling between the active centres formed by localized states and the defect states of the two-dimensional (2D) photonic crystal can be used to select the model in the nanolaser.

  17. Analysis of band gap of non-bravais lattice photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    Yichao MA; Heming CHEN

    2009-01-01

    This article designs a novel type ofnon-bravais lattice photonic crystal fiber. To form the nesting complexperiod with positive and negative refractive index materials respectively, a cylinder with the same radius and negative refractive index is introduced into the center of each lattice unit cell in the traditional square lattice air-holes photonic crystal fiber. The photonic band-gap of the photonic crystal fiber is calculated numerically by the plane wave expansion method. The result shows that compared with the traditional square photonic band-gap fiber (PBGF),when R/A is 0.35, the refractive index of the substrate, airhole, and medium-column are 1.30, 1.0, and -1.0,respectively. This new PBGF can transmit signal by the photonic band-gap effect. When the lattice constant Λvaries from 1.5 μm to 3.0 μm, the range of the wavelength ranges from 880 nm to 2300 nm.

  18. Numerical analysis of Ino.53Gao.47As/InP single photon avalanche diodes

    Institute of Scientific and Technical Information of China (English)

    Zhou Peng; Li Chun-Fei; Liao Chang-Jun; Wei Zheng-Jun; Yuan Shu-Qiong

    2011-01-01

    A rigorous theoretical model for In0.53Ga0.47As/InP single photon avalanche diode is utilized to investigate the dependences of single photon quantum efficiency and dark count probability on structure and operation condition. In the model, low field impact ionizations in charge and absorption layers are allowed, while avalanche breakdown can occur only in the multiplication layer. The origin of dark counts is discussed and the results indicate that the dominant mechanism that gives rise to dark counts depends on both device structure and operating condition. When the multiplication layer is thicker than a critical thickness or the temperature is higher than a critical value, generation-recombination in the absorption layer is the dominative mechanism; otherwise band-to-band tunneling in the multiplication layer dominates the dark counts. The thicknesses of charge and multiplication layers greatly affect the dark count and the peak single photon quantum efficiency and increasing the multiplication layer width may reduce the dark count probability and increase the peak single photon quantum efficiency. However, when the multiplication layer width exceeds 1 μm, the peak single photon quantum efficiency increases slowly and it is finally saturated at the quantum efficiency of the single photon avalanche diodes.

  19. SU-E-T-615: Plan Comparison Between Photon IMRT and Proton Plans Incorporating Uncertainty Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, C; Wessels, B; Jesseph, F; Mattson, D; Mansur, D [Dept of Radiation Oncology, University Hospitals Case Medical Center, Cleveland, OH (United States)

    2015-06-15

    Purpose: In this study, we investigate the effect of setup uncertainty on DVH calculations which may impact plan comparison. Methods: Treatment plans (6 MV VMAT calculated on Pinnacle TPS) were chosen for different disease sites: brain, prostate, H&N and spine in this retrospective study. A proton plan (PP) using double scattering beams was generated for each selected VMAT plan subject to the same set of dose-volume constraints as in VMAT. An uncertainty analysis was incorporated on the DVH calculations in which isocenter shifts from 1 to 5 mm in each of the ±x, ±y and ±z directions were used to simulate the setup uncertainty and residual positioning errors. A total of 40 different combinations of isocenter shifts were used in the re-calculation of DVH of the PTV and the various OARs for both the VMAT and the corresponding PT. Results: For the brain case, both VMAT and PP are comparable in PTV coverage and OAR sparing, and VMAT is a clear choice for treatment due to its ease of delivery. However, when incorporating isoshifts in DVH calculations, a significant change in dose-volume relationship emerges. For example, both VMAT and PT provide adequate coverage, even with ±3mm isoshift. However, +3mm isoshift results in increase of V40(Lcochlea, VMAT) from 7.2% in the original plan to 45% and V40(R cochlea, VMAT) from 75% to 92%. For protons, V40(Lcochlea, PT) increases from 62% in the initial plan to 75%, while V40(Rcochea, PT) increases from 7% to 26%. Conclusion: DVH alone may not be sufficient to allow an unequivocal decision in plan comparison, especially when two rival plans are very similar in both PTV coverage and OAR sparing. It is a good practice to incorporate uncertainty analysis on photon and proton plan comparison studies to test the plan robustness in plan evaluation.

  20. FocusStack and StimServer: a new open source MATLAB toolchain for visual stimulation and analysis of two-photon calcium neuronal imaging data.

    Science.gov (United States)

    Muir, Dylan R; Kampa, Björn M

    2014-01-01

    Two-photon calcium imaging of neuronal responses is an increasingly accessible technology for probing population responses in cortex at single cell resolution, and with reasonable and improving temporal resolution. However, analysis of two-photon data is usually performed using ad-hoc solutions. To date, no publicly available software exists for straightforward analysis of stimulus-triggered two-photon imaging experiments. In addition, the increasing data rates of two-photon acquisition systems imply increasing cost of computing hardware required for in-memory analysis. Here we present a Matlab toolbox, FocusStack, for simple and efficient analysis of two-photon calcium imaging stacks on consumer-level hardware, with minimal memory footprint. We also present a Matlab toolbox, StimServer, for generation and sequencing of visual stimuli, designed to be triggered over a network link from a two-photon acquisition system. FocusStack is compatible out of the box with several existing two-photon acquisition systems, and is simple to adapt to arbitrary binary file formats. Analysis tools such as stack alignment for movement correction, automated cell detection and peri-stimulus time histograms are already provided, and further tools can be easily incorporated. Both packages are available as publicly-accessible source-code repositories.

  1. FocusStack and StimServer: A new open source MATLAB toolchain for visual stimulation and analysis of two-photon calcium neuronal imaging data

    Directory of Open Access Journals (Sweden)

    Dylan Richard Muir

    2015-01-01

    Full Text Available Two-photon calcium imaging of neuronal responses is an increasingly accessible technology for probing population responses in cortex at single cell resolution, and with reasonable and improving temporal resolution. However, analysis of two-photon data is usually performed using ad-hoc solutions. To date, no publicly available software exists for straightforward analysis of stimulus-triggered two-photon imaging experiments. In addition, the increasing data rates of two-photon acquisition systems imply increasing cost of computing hardware required for in-memory analysis. Here we present a Matlab toolbox, FocusStack, for simple and efficient analysis of two-photon calcium imaging stacks on consumer-level hardware, with minimal memory footprint. We also present a Matlab toolbox, StimServer, for generation and sequencing of visual stimuli, designed to be triggered over a network link from a two-photon acquisition system. FocusStack is compatible out of the box with several existing two-photon acquisition systems, and is simple to adapt to arbitrary binary file formats. Analysis tools such as stack alignment for movement correction, automated cell detection and peri-stimulus time histograms are already provided, and further tools can be easily incorporated. Both packages are available as publicly-accessible source-code repositories.

  2. Theoretical Analysis of a Vertical Channel Dropping Tunnelling Process in a Photonic Crystal for Wavelength Division Demultiplexing

    Institute of Scientific and Technical Information of China (English)

    符建; 何赛灵; 肖三水; 仇霪; 何建军

    2001-01-01

    A theoretical analysis is presented for a channel drop tunnelling structure composed of a horizontal input channel, a vertical output channel and a multi-mode cavity in a photonic crystal. Criteria for a complete transfer are derived for applications of wavelength division demultiplexing. The analytical results are verified with a numerical simulation using a finite difference time domain method. The vertical channel dropping tunnelling system makes the demultiplexing device much more compact, as compared to the conventional parallel channel dropping system.

  3. On the Partial-Wave Analysis of Mesonic Resonances Decaying to Multiparticle Final States Produced by Polarized Photons

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Carlos W. [Norfolk State University, Norfolk, VA (United States) and Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Weygand, Dennis P. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2014-04-01

    Meson spectroscopy is going through a revival with the advent of high statistics experiments and new advances in the theoretical predictions. The Constituent Quark Model (CQM) is finally being expanded considering more basic principles of field theory and using discrete calculations of Quantum Chromodynamics (lattice QCD). These new calculations are approaching predictive power for the spectrum of hadronic resonances and decay modes. It will be the task of the new experiments to extract the meson spectrum from the data and compare with those predictions. The goal of this report is to describe one particular technique for extracting resonance information from multiparticle final states. The technique described here, partial wave analysis based on the helicity formalism, has been used at Brookhaven National Laboratory (BNL) using pion beams, and Jefferson Laboratory (Jlab) using photon beams. In particular this report broaden this technique to include production experiments using linearly polarized real photons or quasi-real photons. This article is of a didactical nature. We describe the process of analysis, detailing assumptions and formalisms, and is directed towards people interested in starting partial wave analysis.

  4. Computational Study and Analysis of Structural Imperfections in 1D and 2D Photonic Crystals

    Energy Technology Data Exchange (ETDEWEB)

    Maskaly, Karlene Rosera [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2005-06-01

    Dielectric reflectors that are periodic in one or two dimensions, also known as 1D and 2D photonic crystals, have been widely studied for many potential applications due to the presence of wavelength-tunable photonic bandgaps. However, the unique optical behavior of photonic crystals is based on theoretical models of perfect analogues. Little is known about the practical effects of dielectric imperfections on their technologically useful optical properties. In order to address this issue, a finite-difference time-domain (FDTD) code is employed to study the effect of three specific dielectric imperfections in 1D and 2D photonic crystals. The first imperfection investigated is dielectric interfacial roughness in quarter-wave tuned 1D photonic crystals at normal incidence. This study reveals that the reflectivity of some roughened photonic crystal configurations can change up to 50% at the center of the bandgap for RMS roughness values around 20% of the characteristic periodicity of the crystal. However, this reflectivity change can be mitigated by increasing the index contrast and/or the number of bilayers in the crystal. In order to explain these results, the homogenization approximation, which is usually applied to single rough surfaces, is applied to the quarter-wave stacks. The results of the homogenization approximation match the FDTD results extremely well, suggesting that the main role of the roughness features is to grade the refractive index profile of the interfaces in the photonic crystal rather than diffusely scatter the incoming light. This result also implies that the amount of incoherent reflection from the roughened quarterwave stacks is extremely small. This is confirmed through direct extraction of the amount of incoherent power from the FDTD calculations. Further FDTD studies are done on the entire normal incidence bandgap of roughened 1D photonic crystals. These results reveal a narrowing and red-shifting of the normal incidence bandgap with

  5. High-voltage integrated active quenching circuit for single photon count rate up to 80 Mcounts/s.

    Science.gov (United States)

    Acconcia, Giulia; Rech, Ivan; Gulinatti, Angelo; Ghioni, Massimo

    2016-08-01

    Single photon avalanche diodes (SPADs) have been subject to a fast improvement in recent years. In particular, custom technologies specifically developed to fabricate SPAD devices give the designer the freedom to pursue the best detector performance required by applications. A significant breakthrough in this field is represented by the recent introduction of a red enhanced SPAD (RE-SPAD) technology, capable of attaining a good photon detection efficiency in the near infrared range (e.g. 40% at a wavelength of 800 nm) while maintaining a remarkable timing resolution of about 100ps full width at half maximum. Being planar, the RE-SPAD custom technology opened the way to the development of SPAD arrays particularly suited for demanding applications in the field of life sciences. However, to achieve such excellent performance custom SPAD detectors must be operated with an external active quenching circuit (AQC) designed on purpose. Next steps toward the development of compact and practical multichannel systems will require a new generation of monolithically integrated AQC arrays. In this paper we present a new, fully integrated AQC fabricated in a high-voltage 0.18 µm CMOS technology able to provide quenching pulses up to 50 Volts with fast leading and trailing edges. Although specifically designed for optimal operation of RE-SPAD devices, the new AQC is quite versatile: it can be used with any SPAD detector, regardless its fabrication technology, reaching remarkable count rates up to 80 Mcounts/s and generating a photon detection pulse with a timing jitter as low as 119 ps full width at half maximum. The compact design of our circuit has been specifically laid out to make this IC a suitable building block for monolithically integrated AQC arrays.

  6. Photon transport in binary photonic lattices

    OpenAIRE

    Rodríguez-Lara, B. M.; Moya-Cessa, H.

    2013-01-01

    We present a review on the mathematical methods used to theoretically study classical propagation and quantum transport in arrays of coupled photonic waveguides. We focus on analysing two types of binary photonic lattices where self-energies or couplings are alternated. For didactic reasons, we split the analysis in classical propagation and quantum transport but all methods can be implemented, mutatis mutandis, in any given case. On the classical side, we use coupled mode theory and present ...

  7. The analysis of photon pair source at telecom wavelength based on the BBO crystal (Conference Presentation)

    Science.gov (United States)

    Gajewski, Andrzej; Kolenderski, Piotr L.

    2016-10-01

    There are several problems that must be solved in order to increase the distance of quantum communication protocols based on photons as an information carriers. One of them is the dispersion, whose effects can be minimized by engineering spectral properties of transmitted photons. In particular, it is expected that positively correlated photon pairs can be very useful. We present the full characterization of a source of single photon pairs at a telecom wavelength based on type II spontaneous parametric down conversion (SPDC) process in a beta-barium borate (BBO) crystal. In the type II process, a pump photon, which is polarized extraordinarily, splits in a nonlinear medium into signal and idler photons, which are polarized perpendicularly to each other. In order for the process to be efficient a phase matching condition must be fulfilled. These conditions originate from momentum and energy conservation rules and put severe restrictions on source parameters. Seemingly, these conditions force the photon pair to be negatively correlated in their spectral domain. However, it is possible to achieve positive correlation for pulsed pumping. The experimentally available degrees of freedom of a source are the width of the pumping beam, the collected modes' widths, the length of the nonlinear crystal and the duration of the pumping pulse. In our numerical model we use the following figures of merit: the pair production rate, the efficiency of photon coupling into a single mode fiber, the spectral correlation of the coupled photon pair. The last one is defined as the Pearson correlation parameter for a joint spectral distribution. The aim here is to find the largest positive spectral correlation and the highest coupling efficiency. By resorting to the numerical model Ref. [1] we showed in Ref. [2], that by careful adjustment of the pump's and the collected modes' characteristics, one can optimize any of the source's parameters. Our numerical outcomes conform to the

  8. Microwave Photonics

    OpenAIRE

    Seeds, A.J.; Liu, C. P.; T. Ismail; Fice, M. J.; Pozzi, F; Steed, R. J.; Rouvalis, E.; Renaud, C.C.

    2010-01-01

    Microwave photonics is the use of photonic techniques for the generation, transmission, processing and reception of signals having spectral components at microwave frequencies. This tutorial reviews the technologies used and gives applications examples.

  9. Cut-off analysis of 19-cell Yb-doped double-cladding rod-type photonic crystal fibers.

    Science.gov (United States)

    Poli, F; Coscelli, E; Alkeskjold, T T; Passaro, D; Cucinotta, A; Leick, L; Broeng, J; Selleri, S

    2011-05-09

    Yb-doped double-cladding large mode area rod-type photonic crystal fibers are a key component for power scaling in fiber laser systems. Recently, designs with 19-cell core defect, that is with 19 missing air-holes in the center of the photonic crystal cladding, have been proposed, with reported core diameter up to 100 μm. In this paper an analysis of the cut-off wavelength of the first high-order mode in such low-NA fibers is reported, accounting for different approaches for the definition of the cladding effective index. Results have shown that taking into account the finite fiber cross-section and considering the first cladding mode of the actual fiber is mandatory to obtain a correct estimate of the cut-off wavelength.

  10. Analysis of the resolution-bandwidth-noise trade-off in wavelength-based photonic analog-to-digital converters.

    Science.gov (United States)

    Stigwall, Johan; Galt, Sheila

    2006-06-20

    The performance of wavelength-based photonic analog-to-digital converters (ADCs) is theoretically analyzed in terms of resolution and bandwidth as well as of noise tolerance. The analysis applies to any photonic ADC in which the analog input signal is converted into the wavelength of an optical carrier, but special emphasis is put on the spectrometerlike setup in which the wavelength is mapped to a spatial spot position. The binary output signals are then retrieved by an array of fan-out diffractive optical elements that redirect the beam onto the correct detectors. In particular, the case when the input signal controls the wavelength directly such that it will chirp in frequency during each sampling pulse or interval is studied. This chirping obviously broadens the spot on the diffractive optical element array; the effect of this broadening on noise tolerance and comparator accuracy is analytically analyzed, and accurate numerical calculations of the probability of error are presented.

  11. On the Partial-Wave Analysis of Mesonic Resonances Decaying to Multiparticle Final States Produced by Polarized Photons

    CERN Document Server

    Salgado, Carlos W

    2013-01-01

    Meson spectroscopy is going through a revival with the advent of high statistics experiments and new advances in the theoretical predictions. The Constituent Quark Model (CQM) is finally being expanded considering more basic principles of field theory and using discrete calculations of Quantum Chromodynamics (lattice QCD). These new calculations are approaching predictive power for the spectrum of hadronic resonances and decay modes. It will be the task of the new experiments to extract the meson spectrum from the data and compare with those predictions. The goal of this report is to describe one particular technique for extracting resonance information from multiparticle final states. The technique described here, partial wave analysis based on the helicity formalism, has been used at Brookhaven National Laboratory (BNL) using pion beams, and Jefferson Laboratory (JLab) using photon beams. In particular this report broaden this technique to include production experiments using linearly polarized real photons...

  12. Analysis of Photonic Band Gaps in a Two-Dimensional Triangular Lattice with Superconducting Hollow Rods

    Science.gov (United States)

    Diaz-Valencia, B. F.; Calero, J. M.

    2017-02-01

    In this work, we use the plane wave expansion method to calculate photonic band structures in two-dimensional photonic crystals which consist of high-temperature superconducting hollow rods arranged in a triangular lattice. The variation of the photonic band structure with respect to both, the inner radius and the system temperature, is studied, taking into account temperatures below the critical temperature of the superconductor in the low frequencies regime and assuming E polarization of the incident light. Permittivity contrast and nontrivial geometry of the hollow rods lead to the appearance of new band gaps as compared with the case of solid cylinders. Such band gaps can be modulated by means of the inner radius and system temperature.

  13. Calculation and analysis of complex band structure in dispersive and dissipative two-dimensional photonic crystals

    CERN Document Server

    Brûlé, Yoann; Gralak, Boris

    2015-01-01

    Numerical calculation of modes in dispersive and absorptive systems is performed using the finite element method. The dispersion is tackled in the frame of an extension of Maxwell's equations where auxiliary fields are added to the electromagnetic field. This method is applied to multi-domain cavities and photonic crystals including Drude and Drude-Lorentz metals. Numerical results are compared to analytical solutions for simple cavities and to previous results of the literature for photonic crystals, showing excellent agreement. The advantages of the developed method lie on the versatility of the finite element method regarding geometries, and in sparing the use of tedious complex poles research algorithm. Hence the complex spectrum of resonances of non-hermitian operators and dissipative systems, like two-dimensional photonic crystal made of absorbing Drude metal, can be investigated in detail. The method is used to reveal unexpected features of their complex band structures.

  14. Design & Analysis of Optical Lenses by using 2D Photonic Crystals for Sub-wavelength Focusing

    Directory of Open Access Journals (Sweden)

    Rajib Ahmed

    2013-01-01

    Full Text Available 2D Photonic lenses (Convex-Convex, Convex-Plane, Plane-Convex, Concave-Concave, Concave-plane, and PlaneConcave have been designed, simulated and optimized for optical communication using FDTD method. The effect of Crystal structures (Rectangular, Hexagonal, Face centered Cubic (FCC, Body centered Cubic (BCC, variation lattice constant (Λ, hole radius(r, reflective index (n, is demonstrated to get optimized parameters. Finally, with optimized parameters the effect of variation of lens radius on focal lengths and Electrical Field Intensity (Ey is analyzed. Like optical lens, the focal length of photonic lens is also increased with lens radii, has dependency on optical axis. Moreover, with optimized parameters, ConcaveConcave lens have been found as an optimal photonic lens that show sub-wavelength focusing with spatial resolutions-9.22439μm (Rectangular crystal, 7.379512μm (Hexagonal Crystal, 7.840732μm (FCC, BCC.

  15. Numerical simulation and analysis of losses in air-core plastic photonic bandgap fibers

    Institute of Scientific and Technical Information of China (English)

    Tieshan Guan; Mingyang Chen; Zhilong Zhang; Rongjin Yu

    2005-01-01

    @@ The loss properties of air-core plastic photonic bandgap fibers are analyzed by multipole method. Despite the relatively large absorption loss of plastics (PMMA), the contribution of material absorption loss can be reduced significantly through appropriate selection of operating wavelength, number of cladding air-hole rings, radius of air-core, and position of photonic band gap. The transmission loss in this type of fiber can be decreased by an order of magnitude in comparison with that of conventional plastic optical fiber.

  16. Analysis of a broadband dispersion compensating photonic crystal fiber raman amplifier

    DEFF Research Database (Denmark)

    Varshney, Shailendra K.; Saitoh, K.; Koshiba, M.;

    2006-01-01

    Using an accurate full-vectorial finite element method, a realistic model of a fabricated dispersion compensating photonic crystal fiber is analyzed. An almost flat Raman-gain spectrum (gain-ripples at just ±0.48-dB) is obtained using a single pump.......Using an accurate full-vectorial finite element method, a realistic model of a fabricated dispersion compensating photonic crystal fiber is analyzed. An almost flat Raman-gain spectrum (gain-ripples at just ±0.48-dB) is obtained using a single pump....

  17. Polychromatic photons

    DEFF Research Database (Denmark)

    Keller, Ole

    2002-01-01

    A review is given of the space-time wave mechanics of single photons, a subject with an almost century long history. The Landau-Peierls photon wave function, which is related nonlocally to the electromagnetic field is first described, and thereafter the so-called energy wave function, based...... on the positive-frequency Riemann-Silberstein vectors, is discussed. Recent attempts to understand the birth process of a photon emerging from a single atom are summarized. The polychromatic photon concept is introduced, and it is indicated how the wave mechanics of polychromatic photons can be upgraded to wave...

  18. Probing quantum gravity using photons from a flare of the active galactic nucleus Markarian 501 observed by the MAGIC telescope

    CERN Document Server

    Albert, J; Anderhub, H; Antonelli, L A; Antoranz, P; Backes, M; Baixeras, C; Barrio, J A; Bartko, H; Bastieri, D; Becker, J K; Bednarek, W; Berger, K; Bernardini, E; Bigongiari, C; Biland, A; Bock, R K; Bordas, P; Bosch-Ramon, V; Bretz, T; Britvitch, I; Camara, M; Carmona, E; Chilingarian, A; Commichau, S; Contreras, J L; Cortina, J; Costado, M T; Covino, S; Dazzi, F; De Angelis, A; De Cea del Pozo, E; Delgado Mendez, C; de los Reyes, R; De Lotto, B; De Maria, M; De Sabata, F; Dominguez, A; Dorner, D; Doro, M; Errando, M; Fagiolini, M; Ferenc, D; Fernández, E; Firpo, R; Fonseca, M V; Font, L; Galante, N; García-López, R J; Garczarczyk, M; Gaug, M; Göbel, F; Hayashida, M; Herrero, A; Höhne, D; Hose, J; Hsu, C C; Huber, S; Jogler, T; Kranich, D; La Barbera, A; Laille, A; Leonardo, E; Lindfors, E; Lombardi, S; Longo, F; López, M; Lorenz, E; Majumdar, P; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Mariotti, M; Martínez, M; Mazin, D; Meucci, M; Meyer, M; Miranda, J M; Mirzoyan, R; Moles, M; Moralejo, A; Nieto, D; Nilsson, K; Ninkovic, J; Otte, N; Oya, I; Panniello, M; Paoletti, R; Paredes, J M; Pasanen, M; Pascoli, D; Pauss, F; Pegna, R; Pérez-Torres, M A; Persic, M; Peruzzo, L; Piccioli, A; Prada, F; Puchades, N; Raymers, A; Ribó, M; Rico, J; Rissi, M; Robert, A; Rügamer, S; Saggion, A; Saitô, T; Salvati, M; Sanchez-Conde, M; Sartori, P; Satalecka, K; Scalzotto, V; Scapin, V; Schmitt, R; Schweizer, T; Shayduk, M; Shinozaki, K; Sidro, N; Sierpowska-Bartosik, A; Sillanpää, A; Spanier, F; Stamerra, A; Stark, L S; Takalo, L; Tavecchio, F; Temnikov, P; Tescaro, D; Teshima, M; Tluczykont, M; Torres, D F; Turini, N; Vankov, H; Venturini, A; Vitale, V; Wagner, R M; Wittek, W; Zabalza, M; Zandanel, F; Zanin, R; Ellis, Jonathan Richard; Mavromatos, N E; Nanopoulos, D V; Sakharov, Alexander S; Sarkisyan-Grinbaum, E

    2008-01-01

    We use the timing of photons observed by the MAGIC gamma-ray telescope during a flare of the active galaxy Markarian 501 to probe a vacuum refractive index ~ 1-(E/M_QGn)^n, n = 1,2, that might be induced by quantum gravity. The peaking of the flare is found to maximize for quantum-gravity mass scales M_QG1 ~ 0.4x10^18 GeV or M_QG2 ~ 0.6x10^11 GeV, and we establish lower limits M_QG1 > 0.26x10^18 GeV or M_QG2 > 0.39x10^11 GeV at the 95% C.L. Monte Carlo studies confirm the MAGIC sensitivity to propagation effects at these levels. Thermal plasma effects in the source are negligible, but we cannot exclude the importance of some other source effect.

  19. theoretical analysis of finite-height semiconductor-on-insulator based planar photonic crystal waveguides

    DEFF Research Database (Denmark)

    Søndergaard, Thomas; Arentoft, Jesper

    2002-01-01

    A planar photonic crystal waveguide based on the semiconductor-on-insulator (SOI) materials system is analyzed theoretically. Two-dimensional (2-D) calculations and comparison with dispersion relations for the media above and below the finite-height waveguide are used to obtain design guidelines...

  20. Analysis of Analog Photonic Links Employing Multiple-Channel (Arrayed) Receivers

    Science.gov (United States)

    2008-11-07

    Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Gain and Noise Penalty Characterization of Commercial EDFAs ...EXCESS NOISE ARIS- ING FROM INCORPORATION OF AN EDFA . . . . . . . . . . . . . . . . . . . . . . . . 25 iii I EXECUTIVE SUMMARY Analog photonic links...photocurrent, optical amplifiers – predominantly erbium-doped fiber amplifiers ( EDFAs ) – have been readily incorporated into a variety of systems. It is

  1. Theoretical analysis of a biased photonic crystal fiber infiltrated with a negative dielectric anisotropy liquid crystal

    DEFF Research Database (Denmark)

    Weirich, Johannes; Wei, Lei; Lægsgaard, Jesper;

    2009-01-01

    We simulate the PBG mode of a biased Photonic Crystal Fiber (PCF) infiltrated with a Liquid Crystal (LC) with negative dielectric anisotropy. We analyse the voltage induced change of the transmission spectrum, dispersion and losses and compare them to the experimental values....

  2. Generation and analysis of correlated pairs of photons on board a nanosatellite

    Science.gov (United States)

    Chandrasekara, R.; Tang, Z.; Tan, Y. C.; Cheng, C.; Sha, L.; Hiang, G. C.; Oi, D.; Ling, A.

    2016-10-01

    Progress in quantum computers and their threat to conventional public key infrastructure is driving new forms of encryption. Quantum Key Distribution (QKD) using entangled photons is a promising approach. A global QKD network can be achieved using satellites equipped with optical links. Despite numerous proposals, actual experimental work demonstrating relevant entanglement technology in space is limited due to the prohibitive cost of traditional satellite development. To make progress, we have designed a photon pair source that can operate on modular spacecraft called CubeSats. We report the in-orbit operation of the photon pair source on board an orbiting CubeSat and demonstrate pair generation and polarisation correlation under space conditions. The in-orbit polarisation correlations are compatible with ground-based tests, validating our design. This successful demonstration is a major experimental milestone towards a space-based quantum network. Our approach provides a cost-effective method for proving the space-worthiness of critical components used in entangled photon technology. We expect that it will also accelerate efforts to probe the overlap between quantum and relativistic models of physics.

  3. Analysis of photonic band-gap (PBG) structures using the FDTD method

    DEFF Research Database (Denmark)

    Tong, M.S.; Cheng, M.; Lu, Y.L.

    2004-01-01

    In this paper, a number of photonic band-gap (PBG) structures, which are formed by periodic circuit elements printed oil transmission-line circuits, are studied by using a well-known numerical method, the finite-difference time-domain (FDTD) method. The results validate the band-stop filter...

  4. Ultrasmall-angle X-ray scattering analysis of photonic crystal structure

    NARCIS (Netherlands)

    Abramova, V.V.; Sinitskii, A.S.; Grigoryeva, N.A.; Grigoriev, S.V.; Belov, D.V.; Petukhov, A.V.; Mistonov, A.A.; Vasilieva, A.V.; Tretyakov, Y.D.

    2009-01-01

    The results of an ultrasmall angle X ray scattering study of iron(III) oxide inverse opal thin films are presented. The photonic crystals examined are shown to have fcc structure with amount of stacking faults varying among the samples. The method used in this study makes it possible to easily disti

  5. Calculation of BER in multi-channel silicon optical interconnects: comparative analysis of strip and photonic crystal waveguides

    Science.gov (United States)

    You, Jie; Lavdas, Spyros; Panoiu, Nicolae C.

    2016-05-01

    We present an effective approach to evaluate the performance of multi-channel silicon (Si) photonic systems. The system is composed of strip Si photonic waveguides (Si-PhWs) with uniform cross-section or photonic-crystal (PhC) Si waveguides (Si-PhCWs), combined with a set of direct-detection receivers. Moreover, the optical field in each channel is the superposition of a continuous-wave nonreturn-to-zero ON-OFF keying modulated signal and a white Gaussian noise. In order to characterize the optical signal propagation in the waveguides, an accurate mathematical model describing all relevant linear and nonlinear optical effects and its linearized version is employed. In addition, two semi-analytical methods, time- and frequency-domain Karhunen-Loève series expansion, are used to assess the system bit-error-rate (BER). Our analysis reveals that Si-PhCWs provide similar performance as Si-PhWs, but for 100× shorter length. Importantly, much worse BER is achieved in Si-PhCWs when one operates in slow-light regime, due to the enhanced linear and nonlinear effects.

  6. Photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Sanchez Bjarklev, Araceli

    Photonic crystal fibres represent one of the most active research areas today in the field of optics. The diversity of applications that may be addressed by these fibres and their fundamental appeal, by opening up the possibility of guiding light in a radically new way compared to conventional...... optical fibres, have spun an interest from almost all areas of optics and photonics. The aim of this book is to provide an understanding of the different types of photonic crystal fibres and to outline some of the many new and exciting applications that these fibres offer. The book is intended for both...... readers with a general interest in photonic crystals, as well as for scientists who are entering the field and desire a broad overview as well as a solid starting point for further specialized stuides. Teh book, therefore, covers bothe general aspects such as the link from classical optics to photonic...

  7. Development and application of an automated analysis method for individual cerebral perfusion single photon emission tomography images

    CERN Document Server

    Cluckie, A J

    2001-01-01

    Neurological images may be analysed by performing voxel by voxel comparisons with a group of control subject images. An automated, 3D, voxel-based method has been developed for the analysis of individual single photon emission tomography (SPET) scans. Clusters of voxels are identified that represent regions of abnormal radiopharmaceutical uptake. Morphological operators are applied to reduce noise in the clusters, then quantitative estimates of the size and degree of the radiopharmaceutical uptake abnormalities are derived. Statistical inference has been performed using a Monte Carlo method that has not previously been applied to SPET scans, or for the analysis of individual images. This has been validated for group comparisons of SPET scans and for the analysis of an individual image using comparison with a group. Accurate statistical inference was obtained independent of experimental factors such as degrees of freedom, image smoothing and voxel significance level threshold. The analysis method has been eval...

  8. Characterization of x-ray framing cameras for the National Ignition Facility using single photon pulse height analysis

    Science.gov (United States)

    Holder, J. P.; Benedetti, L. R.; Bradley, D. K.

    2016-11-01

    Single hit pulse height analysis is applied to National Ignition Facility x-ray framing cameras to quantify gain and gain variation in a single micro-channel plate-based instrument. This method allows the separation of gain from detectability in these photon-detecting devices. While pulse heights measured by standard-DC calibration methods follow the expected exponential distribution at the limit of a compound-Poisson process, gain-gated pulse heights follow a more complex distribution that may be approximated as a weighted sum of a few exponentials. We can reproduce this behavior with a simple statistical-sampling model.

  9. Performance analysis of communication links based on VCSEL and silicon photonics technology for high-capacity data-intensive scenario.

    Science.gov (United States)

    Boletti, A; Boffi, P; Martelli, P; Ferrario, M; Martinelli, M

    2015-01-26

    To face the increased demand for bandwidth, cost-effectiveness and simplicity of future Ethernet data communications, a comparison between two different solutions based on directly-modulated VCSEL sources and Silicon Photonics technologies is carried out. Also by exploiting 4-PAM modulation, the transmission of 50-Gb/s and beyond capacity per channel is analyzed by means of BER performance. Applications for optical backplane, very short reach and in case of client-optics networks and intra and inter massive data centers communications (up to 10 km) are taken into account. A comparative analysis based on the power consumption is also proposed.

  10. Analysis of a distributed fiber-optic temperature sensor using single-photon detectors

    CERN Document Server

    Dyer, Shellee D; Baek, Burm; Hadfield, Robert H; Nam, Sae Woo

    2011-01-01

    We demonstrate a high-accuracy distributed fiber-optic temperature sensor using superconducting nanowire single-photon detectors and single-photon counting techniques. Our demonstration uses inexpensive single-mode fiber at standard telecommunications wavelengths as the sensing fiber, which enables extremely low-loss experiments and compatibility with existing fiber networks. We show that the uncertainty of the temperature measurement decreases with longer integration periods, but is ultimately limited by the calibration uncertainty. Temperature uncertainty on the order of 3 K is possible with spatial resolution of the order of 1 cm and integration period as small as 60 seconds. Also, we show that the measurement is subject to systematic uncertainties, such as polarization fading, which can be reduced with a polarization diversity receiver.

  11. Kinetics simulation of luminol chemiluminescence based on quantitative analysis of photons generated in electrochemical oxidation.

    Science.gov (United States)

    Koizumi, Yozo; Nosaka, Yoshio

    2013-08-22

    The kinetics of electrogenerated chemiluminescence (ECL) of luminol at a gold electrode in alkaline solution was investigated by measuring the absolute number of photons emitted in an integrating sphere. The ECL efficiency as the ratio of photon to electric charge was 0.0004 in cyclic voltammography and 0.0005 in chronoamperometry. By numerically solving the rate equations based on a diffusion layer model, the observed time profile of the luminescence intensity could be successfully simulated from the oxidation current of luminol in the chronoamperometry. In the simulation, the rate constant for the oxidation of luminol by superoxide radicals in alkaline solution was determined to be 6 × 10(5) M(-1) s(-1). The present methodology and the achievement could be widely applicable to various analytical techniques using chemiluminescence.

  12. Analysis of arbitrary defects in photonic crystals by use of the source-model technique.

    Science.gov (United States)

    Ludwig, Alon; Leviatan, Yehuda

    2004-07-01

    A novel method derived from the source-model technique is presented to solve the problem of scattering of an electromagnetic plane wave by a two-dimensional photonic crystal slab that contains an arbitrary defect (perturbation). In this method, the electromagnetic fields in the perturbed problem are expressed in terms of the field due to the periodic currents obtained from a solution of the corresponding unperturbed problem plus the field due to yet-to-be-determined correction current sources placed in the vicinity of the perturbation. Appropriate error measures are suggested, and a few representative structures are presented and analyzed to demonstrate the versatility of the proposed method and to provide physical insight into waveguiding and defect coupling mechanisms typical of finite-thickness photonic crystal slabs.

  13. Analysis of a Triple-cavity Photonic Molecule Based on Coupled Mode Theory

    CERN Document Server

    Yang, Chao; Jiang, Xiaoshun; Xiao, Min

    2016-01-01

    In this paper, we analyze a chain-linked triple-cavity photonic molecule (TCPM) with controllable coupling strengths between the cavities on their spectral properties and field (energy) distributions by solving eigenvalues and eigenvectors of the Hamiltonian matrix based on coupled mode theory. Phase transition is extended from double-cavity photonic molecules (DCPMs) to TCPMs, and evolutions of the supermode frequencies and linewidths are analyzed, which have synchronous relations with the degree of coherence between adjacent optical microcavities and energy distributions in the three cavities, respectively. We develop a superposition picture for the three supermodes of the TCPM, as interferences between supermodes of sub-DCPMs. In particular, we demonstrate the abnormal properties of the central supermode in TCPMs, such as dark state in middle cavity and phase shift when energy flowing between side cavities, which are promising in information processing and remote control of energy. General properties of TC...

  14. Activating photonic crystal membrane nanocavities by infiltrating with liquid crystals or luminescent colloidal nanocrystals

    NARCIS (Netherlands)

    Dündar, M.A.; Christova, C.; Silov, A.Y.; Karouta, F.; Nötzel, R.; Wienk, M.; Salemink, H.; Van der Heijden, R.W.

    2010-01-01

    Liquid crystal (LC, Merk 5 CB) is infiltrated into active, InAs quantum dots embedded, InGaAsP membrane type nanocavities to investigate the possible effect of the LC orientation on active cavity tuning. The tuning is demonstrated thermally and thermo-optically. The thermal tuning showed that the ca

  15. Activating photonic crystal membrane nanocavities by infiltrating with liquid crystals or luminescent colloidal nanocrystals

    NARCIS (Netherlands)

    Dündar, M.A.; Christova, C.; Silov, A.Y.; Karouta, F.; Nötzel, R.; Wienk, M.; Salemink, H.; Van der Heijden, R.

    2010-01-01

    Liquid crystal (LC, Merk 5 CB) is infiltrated into active, InAs quantum dots embedded, InGaAsP membrane type nanocavities to investigate the possible effect of the LC orientation on active cavity tuning. The tuning is demonstrated thermally and thermo-optically. The thermal tuning showed that the c

  16. Bending Loss Analysis of Optical Fiber with Out-Cladding of Photonic Crystals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new type of optical fiber is presented here. It consists of a coaxial optical fiber, bounded by dielectric, multilayer and omnidirectional reflecting mirrors. Jones matrix method is used to analyze the influence of the layer number of one-Dimensional (1D) photonic crystals on their reflectivity. The numerical results show that this type of fiber can be used to guide light around sharp bends whose radius of curvature can be as small as the wavelength of light without significant scattering losses.

  17. Three-Dimensional Thermal Analysis of 18-Core Photonic Crystal Fiber Lasers

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yi-Bo; YAO Jian-Quan; ZHANG Lei; WANG Yuan; WEN Wu-Qi; JING Lei; DI Zhi-Gang

    2012-01-01

    The three-dimensional thermal properties of 18-core photonic crystal fiber lasers operated under natural convection are investigated. The temperature sensing technique based on a fiber Bragg grating sensor array is proposed to measure the longitudinal temperature distribution of a 1.6-m-long ytterbium-doped 18-core photonic crystal fiber. The results show that the temperature decreases from the pump end to the launch end exponentially. Moreover, the radial temperature distribution of the fiber end is investigated by using the full-vector finite-element method. The numerical results match well with the experimental data and the coating temperature reaches 422.7K, approaching the critical value of polymer cladding, when the pumping power is 40 W. Therefore the fiber end cooling is necessary to achieve power scaling. Compared with natural convection methods, the copper cooling scheme is found to be an effective method to reduce the fiber temperature.%The three-dimensional thermal properties of 18-core photonic crystal fiber lasers operated under natural convection are investigated.The temperature sensing technique based on a fiber Bragg grating sensor array is proposed to measure the longitudinal temperature distribution of a 1.6-m-long ytterbium-doped 18-core photonic crystal fiber.The results show that the temperature decreases from the pump end to the launch end exponentially.Moreover,the radial temperature distribution of the fiber end is investigated by using the full-vector finite-element method.The numerical results match well with the experimental data and the coating temperature reaches 422.7K,approaching the critical value of polymer cladding,when the pumping power is 40 W.Therefore the fiber end cooling is necessary to achieve power scaling.Compared with natural convection methods,the copper cooling scheme is found to be an effective method to reduce the fiber temperature.

  18. Increased upconversion quantum yield in photonic structures due to local field enhancement and modification of the local density of states--a simulation-based analysis.

    Science.gov (United States)

    Herter, Barbara; Wolf, Sebastian; Fischer, Stefan; Gutmann, Johannes; Bläsi, Benedikt; Goldschmidt, Jan Christoph

    2013-09-09

    In upconversion processes, two or more low-energy photons are converted into one higher-energy photon. Besides other applications, upconversion has the potential to decrease sub-band-gap losses in silicon solar cells. Unfortunately, upconverting materials known today show quantum yields, which are too low for this application. In order to improve the upconversion quantum yield, two parameters can be tuned using photonic structures: first, the irradiance can be increased within the structure. This is beneficial, as upconversion is a non-linear process. Second, the rates of the radiative transitions between ionic states within the upconverter material can be altered due to a varied local density of photonic states. In this paper, we present a theoretical model of the impact of a photonic structure on upconversion and test this model in a simulation based analysis of the upconverter material β -NaYF(4):20% Er(3+) within a dielectric waveguide structure. The simulation combines a finite-difference time-domain simulation model that describes the variations of the irradiance and the change of the local density of photonic states within a photonic structure, with a rate equation model of the upconversion processes. We find that averaged over the investigated structure the upconversion luminescence is increased by a factor of 3.3, and the upconversion quantum yield can be improved in average by a factor of 1.8 compared to the case without the structure for an initial irradiance of 200 Wm(-2).

  19. New developments in two-photon analysis of human skin in vivo

    Science.gov (United States)

    Riemann, I.; Schwarz, M.; Stracke, F.; Ehlers, A.; Dimitrow, E.; Kaatz, M.; König, K.; Le Harzic, R.

    2009-02-01

    Two-photon imaging of human skin using ultra short laser pulses can be used to obtain information about the state of cells and tissues by means of their natural autofluorescence. Using this method, it is possible to determine whether the normal cell pattern is disturbed or the autofluorescence is influenced by internal or external stimuli. Two-photon fluorescence lifetime imaging (FLIM) can further enhance this providing information about physiological processes, fluorophores (like NAD(P)H, collagen, keratin, elastin, flavins, melanin,...) and external applied probes inside cells and tissue parts. For example the part of the cells metabolism and energy level can be determined by analyzing the NADH regarding its free / bound state and its oxidized / reduced state. The combination of two-photon imaging with FLIM may lead to a better understanding and diagnosis of skin reactions and disorders. We also present some results of in vivo simultaneous collagen and elastin measurements in skin dermis. Changes of dermal collagen and elastin content are characteristic for skin aging as well as for pathological skin conditions.

  20. Two-photon light-sheet nanoscopy by fluorescence fluctuation correlation analysis

    Science.gov (United States)

    Chen, Xuanze; Zong, Weijian; Li, Rongqin; Zeng, Zhiping; Zhao, Jia; Xi, Peng; Chen, Liangyi; Sun, Yujie

    2016-05-01

    Advances in light-sheet microscopy have enabled the fast three-dimensional (3D) imaging of live cells and bulk specimens with low photodamage and phototoxicity. Combining light-sheet illumination with super-resolution imaging is expected to resolve subcellular structures. Actually, such kind of super-resolution light-sheet microscopy was recently demonstrated using a single-molecule localization algorithm. However, the imaging depth and temporal resolution of this method are limited owing to the requirements of precise single molecule localization and reconstruction. In this work, we present two-photon super-resolution light-sheet imaging via stochastic optical fluctuation imaging (2PLS-SOFI), which acquires high spatiotemporal resolution and excellent optical sectioning ability. 2PLS-SOFI is based on non-linear excitation of fluctuation/blinking probes using our recently developed fast two-photon three-axis digital scanned light-sheet microscope (2P3A-DSLM), which enables both deep penetration and thin sheet of light. Overall, 2PLS-SOFI demonstrates up to 3-fold spatial resolution enhancement compared with conventional two-photon light-sheet (2PLS) microscopy and about 40-fold temporal resolution enhancement compared with individual molecule localization-selective plane illumination microscopy (IML-SPIM). Therefore, 2PLS-SOFI is promising for 3D long-term, deep-tissue imaging with high spatiotemporal resolution.

  1. Numerical analysis of a photonic crystal fiber based on two polarized modes for biosensing applications

    Institute of Scientific and Technical Information of China (English)

    Qin Wei; Li Shu-Guang; Xue Jian-Rong; Xin Xü-Jun; Zhang Lei

    2013-01-01

    This paper presents a theoretical study on a photonic crystal fiber plasmonic refractive index biosensor.The proposed photonic crystal fiber sensor introduces the concept of simultaneous detection with the linearly polarized and radially polarized modes because the sensing performance of the sensor based on both modes is relatively high,which will be useful for selecting the modes to make the detection accurately.The sharp single resonant peaks of the linearly polarized mode and radially polarized mode,are stronger and more sensitive to the variation of analyte refractive index than that of any other polarized mode in this kind of photonic crystal fiber.For linearly polarized mode and radially polarized mode,the maximum sensitivities of 10448.5 nm per refractive index unit and 8230.7 nm per refractive index unit can be obtained,as well as 949.8 and 791.4 for figure of merits in the sensing range of 1.33-1.45,respectively.Compared with the conventional Au-metalized surface plasmon resonance sensors,our device is better and can be applied as a biosensor.

  2. Distortion-free spectrum sliced microwave photonic signal processor: analysis, design and implementation.

    Science.gov (United States)

    Li, Liwei; Yi, Xiaoke; Huang, Thomas X H; Minasian, Robert A

    2012-05-01

    A new switchable microwave photonic filter based on a novel spectrum slicing technique is presented. The processor enables programmable multi-tap generation with general transfer function characteristics and offers tunability, reconfigurabiliy, and switchability. It is based on connecting a dispersion controlled spectrum slicing filter after the modulated bipolar broadband light source, which consequently generates multiple spectrum slices with bipolarity, and compensates dispersion induced RF degradation simultaneously within a single device. A detailed theoretical model for this microwave photonic filter design is presented. Experimental results are presented which verify the model, and demonstrate a 33 bipolar-tap microwave filter with significant reduction of passband attenuations at high frequencies. The RF response improvement of the new microwave photonic filter is investigated, for both an ideal linear group delay line and for the experimental fiber delay line that has second order group delay and the results show that this new structure is effective for RF filters with various free spectral range values and spectrum slice bandwidths. Finally, a switchable bipolar filter that has a square-top bandpass filter response with more than 30 dB stopband attenuation that can be switched on/off via software control is demonstrated.

  3. Photonic Lantern

    CERN Document Server

    Leon-Saval, Sergio; Bland-Hawthorn, Joss

    2015-01-01

    Photonic lanterns allow for a low-loss transformation of a multimode waveguide into a discrete number of single-mode waveguides and vice versa, thus, enabling the use of single-mode photonic technologies in multimode systems. In this review, we will discuss the theory and function of the photonic lantern, along with several different variants of the technology. We will also discuss some of its applications in more detail.

  4. Search for supersymmetry in events with at least one photon, missing transverse momentum, and large transverse event activity in proton-proton collisions at 13 TeV

    CERN Document Server

    CMS Collaboration

    2017-01-01

    A search for physics beyond the standard model in final states with at least one photon, large transverse momentum imbalance, and large total transverse event activity is presented. This event selection provides good sensitivity for gauge mediated supersymmetry models in which pair-produced gluinos or squarks decay via short-living neutralinos to photons and gravitinos. The data sample corresponds to an integrated luminosity of $35.9~\\mathrm{fb}^{-1}$ of proton-proton collisions recorded by the CMS experiment at the LHC in 2016. No excess of events above the standard model background is observed. The data is interpreted in simplified models of gluino- and squark pair production, in which gluinos and squarks decay via gauginos to photons. Gluino masses of up to $2~\\mathrm{TeV}$ masses up to $1.6~\\mathrm{TeV}$ are excluded.

  5. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2006-01-01

    Wireless, optical, and electronic networks continue to converge, prompting heavy research into the interface between microwave electronics, ultrafast optics, and photonic technologies. New developments arrive nearly as fast as the photons under investigation, and their commercial impact depends on the ability to stay abreast of new findings, techniques, and technologies. Presenting a broad yet in-depth survey, Microwave Photonics examines the major advances that are affecting new applications in this rapidly expanding field.This book reviews important achievements made in microwave photonics o

  6. Automated image analysis for diameters and branching points of cerebral penetrating arteries and veins captured with two-photon microscopy.

    Science.gov (United States)

    Sugashi, Takuma; Yoshihara, Kouichi; Kawaguchi, Hiroshi; Takuwa, Hiroyuki; Ito, Hiroshi; Kanno, Iwao; Yamada, Yukio; Masamoto, Kazuto

    2014-01-01

    The present study was aimed to characterize 3-dimensional (3D) morphology of the cortical microvasculature (e.g., penetrating artery and emerging vein), using two-photon microscopy and automated analysis for their cross-sectional diameters and branching positions in the mouse cortex. We observed that both artery and vein had variable cross-sectional diameters across cortical depths. The mean diameter was similar for both artery (17 ± 5 μm) and vein (15 ± 5 μm), and there were no detectable differences over depths of 50-400 μm. On the other hand, the number of branches was slightly increased up to 400-μm depth for both the artery and vein. The mean number of branches per 0.1 mm vessel length was 1.7 ± 1.2 and 3.8 ± 1.6 for the artery and vein, respectively. This method allows for quantification of the large volume data of microvascular images captured with two-photon microscopy. This will contribute to the morphometric analysis of the cortical microvasculature in functioning brains.

  7. Clinical studies of brain functional images by motor activation using single photon emission computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kawaguchi, Masahiro [Gifu Univ. (Japan). School of Medicine

    1998-09-01

    Thirty participants (10 normal controls; group A, 5 patients with brain tumors located near central sulcus without hemiparesis; group B, 10 patients with brain tumors located near central sulcus with hemiparesis; group C, and 5 patients with brain tumors besides the central regions with hemiparesis; group D) were enrolled. The images were performed by means of split-dose method with {sup 99m}Tc-ECD at rest condition (SPECT 1) and during hand grasping (SPECT 2). The activation SPECT were obtained by subtracting SPECT 1 from SPECT 2, and the functional mapping was made by the strict registration of the activation SPECT with 3D MRI. To evaluate the changes of CBF (%{Delta}CBF) of the sensorimotor and supplementary motor areas on the functional mapping, ratio of the average counts of SPECT 1 and SPECT 2 was calculated and statistically compared. The functional activation paradigms caused a significant increase of CBF in the sensorimotor area contra-lateral to the stimulated hand, although the sensorimotor area and the central sulcus in groups B and C were dislocated, compared with hemisphere of non-tumor side. The sensorimotor area ipsi-lateral to the stimulated hand could be detected in almost of all subjects. The supplementary motor area could be detected in all subjects. In group A, the average %{Delta}CBF were up 24.1{+-}4.3% in the contra-lateral sensorimotor area, and 22.3{+-}3.6% in the supplementary motor area, respectively. The average %{Delta}CBF in the contra-lateral sensorimotor area of group D was significantly higher than that of group A. The brain functional mapping by motor activation using SPECT could localize the area of cortical motor function in normal volunteers and patients with brain tumors. The changes of regional CBF by activation SPECT precisely assess the cortical motor function even in patients with brain tumors located near central sulcus. (K.H.)

  8. ANALYSIS OF INDEXED-GUIDED HIGHLY BIREFRINGENT PHOTONIC CRYSTAL FIBER EMPLOYING DIFFERENT CLADDING GEOMETRIES

    Directory of Open Access Journals (Sweden)

    A. M. Jouri

    2015-07-01

    Full Text Available      In this paper, a comparative study of three geometries of highly birefringent photonic crystal fibers (HB PCF is presented. The proposed geometries are: V type PCF, Pseudo-Panda PCF and selectively liquid-filled PCF. Based on the famous Finite Difference Time Domain (FDTD method with the perfectly matched layer (PML boundary condition, the simulations are carried out in the aim to find a tradeoff between the chromatic dispersion, the birefringence and the confinement loss.

  9. Ultrafast polarization optical switch constructed from one-dimensional photonic crystal and its performance analysis

    Institute of Scientific and Technical Information of China (English)

    WANG Tao; LI Qing; GAO DingShan

    2009-01-01

    All-optical switch with the ultrafast optical switching rate is a key device in the next generation optical network. In this article, we propose a polarization switch with ps switching time, which is constructed from one-dimensional resonant photonic crystal (1D RPC). The model of switch operating at 1.5 μm is established based on the optical stark effect (OSE). We calculate the performance indices of the switch and the influences of errors of periods and refractive index on the performance characteristics.

  10. Analysis of cutoff frequency in a one-dimensional superconductor-metamaterial photonic crystal

    Science.gov (United States)

    Aly, Arafa H.; Aghajamali, Alireza; Elsayed, Hussein A.; Mobarak, Mohamed

    2016-09-01

    In this paper, using the two-fluid model and the characteristic matrix method, we investigate the transmission characteristics of the one-dimensional photonic crystal. Our structure composed of the layers of low-temperature superconductor material (NbN) and double-negative metamaterial. We target studying the effect of many parameters such as the thickness of the superconductor material, the thickness of the metamaterial layer, and the operating temperature. We show that the cut-off frequency can be tuned efficiently by the operating temperature as well as the thicknesses of the constituent materials.

  11. Neutron-photon mixed field dosimetry by TLD-700 glow curve analysis and its implementation in dose monitoring for Boron Neutron Capture Therapy (BNCT) treatments

    Energy Technology Data Exchange (ETDEWEB)

    Boggio, E. F.; Longhino, J. M. [Centro Atomico Bariloche, Departamento de Fisica de Reactores y Radiaciones / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina); Andres, P. A., E-mail: efboggio@cab.cnea.gov.ar [Centro Atomico Bariloche, Division Proteccion Radiologica / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina)

    2015-10-15

    BNCT is a cancerous cells selective, non-conventional radiotherapy modality to treat malignant tumors such as glioblastoma, melanoma and recurrent head and neck cancer. It consists of a two-step procedure: first, the patient is injected with a tumor localizing drug containing a non-radioactive isotope (Boron-10) with high slow neutron capture cross-section. In a second step, the patient is irradiated with neutrons, which are absorbed by the Boron-10 agent with the subsequently nuclear reaction B- 10(n,a)Li-7, thereby resulting in dose at cellular level due to the high-Let particles. The neutron fields suitable for BNCT are characterized by high neutron fluxes and low gamma dose. Determination of each component is not an easy task, especially when the volume of measurement is quite small or inaccessible for a miniature ionization chamber, for example. A method of measuring the photon and slow neutron dose(mainly by N-14 and B-10) from the glow curve (GC) analysis of a single {sup 7}LiF thermoluminescence detector is evaluated. This method was suggested by the group headed by Dr. Grazia Gambarini. The dosemeters used were TLD-600 ({sup 6}LiF:Mg,Ti with 95.6% {sup 6}Li) and TLD-700 ({sup 7}LiF:Mg,Ti with 99.9% {sup 7}LiF) from Harshaw. Photon dose measurement using the GC analysis method with TLD-700 in mixed fields requires the relation of the two main peaks of a TLD-600 GC shape obtained from an exposition to the same neutron field, and a photon calibrated GC with TLD-700. The requirements for slow neutron dose measurements are similar. In order to properly apply the GC analysis method at the Ra-6 Research Reactor BNCT facility, measurements were carried out in a standard water phantom, fully characterized on the BNCT beam by conventional techniques (activation detectors and paired ionization chambers technique). Next, the method was implemented in whole body dose monitoring of a patient undergoing a BNCT treatment, using a Bo MAb (Bottle Manikin Absorption) phantom

  12. Low noise patch-clamp current amplification by nanoparticles plasmonic-photonic coupling (analysis and modelling).

    Science.gov (United States)

    Haberal, E O; SalmanOgli, A; Nasseri, B

    2016-10-01

    In this article, a patch-clamp low noise current amplification based on nanoparticles plasmonic radiation is analyzed. It is well-known, a very small current is flowing from different membrane channels and so, for extra processing the current amplification is necessary. It is notable that there are some problems in traditional electronic amplifier due to its noise and bandwidth problem. Because of the important role of the patch-clamp current in cancer research and especially its small amplitude, it is vital to intensify it without adding any noises. In this study, the current amplification is performed firstly: from the excitement of nanoparticles by the patch-clamp pico-ampere current and then, the effect of nanoparticles plasmonic far-field radiation on conductor's carriers, which will cause the current amplification. This relates to the plasmonic-photonic coupling and their effect on conductor carriers as the current perturbation agent. In the steady state, the current amplification can reach to 1000 times of initial level. Furthermore, we investigated the nanoparticles morphology changing effect such as size, nanoparticles inter-distance, and nanoparticles distance from the conductor on the amplifier parameters. Finally, it should note that the original aim is to use nanoparticles plasmonic engineering and their coupling to photonics for output current manipulating.

  13. Lidar Waveform-Based Analysis of Depth Images Constructed Using Sparse Single-Photon Data.

    Science.gov (United States)

    Altmann, Yoann; Ren, Ximing; McCarthy, Aongus; Buller, Gerald S; McLaughlin, Steve

    2016-05-01

    This paper presents a new Bayesian model and algorithm used for depth and reflectivity profiling using full waveforms from the time-correlated single-photon counting measurement in the limit of very low photon counts. The proposed model represents each Lidar waveform as a combination of a known impulse response, weighted by the target reflectivity, and an unknown constant background, corrupted by Poisson noise. Prior knowledge about the problem is embedded through prior distributions that account for the different parameter constraints and their spatial correlation among the image pixels. In particular, a gamma Markov random field (MRF) is used to model the joint distribution of the target reflectivity, and a second MRF is used to model the distribution of the target depth, which are both expected to exhibit significant spatial correlations. An adaptive Markov chain Monte Carlo algorithm is then proposed to perform Bayesian inference. This algorithm is equipped with a stochastic optimization adaptation mechanism that automatically adjusts the parameters of the MRFs by maximum marginal likelihood estimation. Finally, the benefits of the proposed methodology are demonstrated through a series of experiments using real data.

  14. UNESCO active learning approach in optics and photonics leads to significant change in Morocco

    Science.gov (United States)

    Berrada, K.; Channa, R.; Outzourhit, A.; Azizan, M.; Oueriagli, A.

    2014-07-01

    There are many difficulties in teaching science and technology in developing countries. Several different teaching strategies have to be applied in these cases. More specifically, for developing countries competencies in teaching science in the introductory classroom has attracted much attention. As a specific example we will consider the Moroccan system. In most developing countries everything is moving so slowly that the progress stays static for development. Also, any change needs time, effort and engagement. In our case we discovered that many teachers feel uncomfortable when introducing new teaching methods and evaluation in classes at introductory physics. However, the introduction of an Active Learning in our curricula showed difficulties that students have in understanding physics and especially concepts. Students were interested in having Active Learning courses much more than passive and traditional ones. Changing believes on physical phenomena and reality of the world students become more attractive and their way of thinking Science changed. The main philosophy of fostering modern hands-on learning techniques -adapted to local needs and availability of teaching resources- is elaborated. The Active Learning program provides the teachers with a conceptual evaluation instrument, drawn from relevant physics education research, giving teachers an important tool to measure student learning. We will try to describe the UNESCO Chair project in physics created in 2010 at Cadi Ayyad University since our first experience with UNESCO ALOP program. Many efforts have been done so far and the project helps now to develop more national and international collaborations between universities and Regional Academies of Education and Training. As a new result of these actions and according to our local needs, the translation of the ALOP program into Arabic is now available under the auspice of UNESCO and encouragement of international partners SPIE, ICTP, ICO and OSA.

  15. An examination of athermal photonic effects on boron diffusion and activation during microwave rapid thermal processing.

    Science.gov (United States)

    Bonifas, Christopher J; Thompson, Keith; Booske, John H; Cooper, Reid F

    2008-01-01

    This work examines the role of 672 nm optical illumination on the diffusion and activation of B in Si as a function of various factors. The factors studied include length of anneal, maximum temperature of anneal, type of co-implanted and pre-amorphizing species and ambient oxygen concentration. The anneal conditions fell into one of three categories: (1) high-temperature (> 900 degrees C) spike and 10-second anneals; (2) low temperature (550 degrees C) 30-minute anneals; and (3) room-temperature long-term "anneals". Implanted species included BF2 implants, pre-amorphized B-only implants, and pre-amorphized BF2 implants. Finally, the ambient oxygen concentration was varied from atmospheric pressure to 100 ppm. The results show that illumination: (1) affects the diffusion of B on spike anneal time frames; (2) has limited effect on diffusion over 10-second time frames; and (3) fails to enhance the activation of B during low-temperature solid phase epitaxy and at room temperature. Additionally, illumination has no effect on B-diffusion when oxygen is present in ambient concentrations but does show an effect when the presence of oxygen is restricted. Finally, the presence of F affects both the net diffusion of B in Si and the relative effect of illumination on the diffusion of B.

  16. Photochemical Modulation of Ras-Mediated Signal Transduction using Caged Farnesyltransferase Inhibitors: Activation via One- and Two-Photon Excitation

    Science.gov (United States)

    Abate-Pella, Daniel; Zeliadt, Nicholette A.; Ochocki, Joshua D.; Warmka, Janel K.; Dore, Timothy M.; Blank, David A.; Wattenberg, Elizabeth V.; Distefano, Mark D.

    2012-01-01

    The creation of caged molecules involves the attachment of protecting groups to biologically active compounds such as ligands, substrates, and drugs that can be removed under specific conditions. Photoremovable caging groups are the most common due to their ability to be removed with high spatial and temporal resolution. Here, the synthesis and photochemistry of a caged inhibitor of protein farnesyltransferase, Bhc-FTI, is described. The inhibitor was caged by alkylation of a critical thiol functional group with a Bhc moiety; while Bhc is well established as a protecting group for carboxylates and phosphates, it has not been extensively used to cage sulfhydryls. The resulting caged molecule, Bhc-FTI, can be photolyzed with UV light to release the inhibitor (FTI) that prevents Ras farnesylation, Ras membrane localization and downstream signaling. Finally, it is shown that Bhc-FTI can be uncaged by two-photon excitation to produce FTI at levels sufficient to inhibit Ras localization and alter cell morphology. Given the widespread involvement of Ras proteins in signal transduction pathways, this caged inhibitor should be useful in a plethora of studies. PMID:22492666

  17. Photochemical modulation of Ras-mediated signal transduction using caged farnesyltransferase inhibitors: activation by one- and two-photon excitation.

    Science.gov (United States)

    Abate-Pella, Daniel; Zeliadt, Nicholette A; Ochocki, Joshua D; Warmka, Janel K; Dore, Timothy M; Blank, David A; Wattenberg, Elizabeth V; Distefano, Mark D

    2012-05-07

    The creation of caged molecules involves the attachment of protecting groups to biologically active compounds such as ligands, substrates and drugs that can be removed under specific conditions. Photoremovable caging groups are the most common due to their ability to be removed with high spatial and temporal resolution. Here, the synthesis and photochemistry of a caged inhibitor of protein farnesyltransferase is described. The inhibitor, FTI, was caged by alkylation of a critical thiol group with a bromohydroxycoumarin (Bhc) moiety. While Bhc is well established as a protecting group for carboxylates and phosphates, it has not been extensively used to cage sulfhydryl groups. The resulting caged molecule, Bhc-FTI, can be photolyzed with UV light to release the inhibitor that prevents Ras farnesylation, Ras membrane localization and downstream signaling. Finally, it is shown that Bhc-FTI can be uncaged by two-photon excitation to produce FTI at levels sufficient to inhibit Ras localization and alter cell morphology. Given the widespread involvement of Ras proteins in signal transduction pathways, this caged inhibitor should be useful in a plethora of studies.

  18. Material Classification by Analysis of Prompt Photon Spectra Induced by 14-Mev Neutrons

    Science.gov (United States)

    Barzilov, Alexander; Novikov, Ivan

    Neutron based technologies are widely used in the field of bulk material analysis. These methods employ characteristic prompt gamma rays induced by a neutron probe for classification of the interrogated object using the elemental parameters extracted from the spectral data. Automatic data analysis and material classification algorithms are required for applications where access to nuclear spectroscopy expertise is limited and/or the autonomous robotic operation is necessary. Data obtained with neutron based systems differ from elemental composition evaluations based on chemical formulae due to statistical nature of nuclear reactions, presence of shielding and cladding, and other environmental conditions. Experimental data that are produced by the spectral decomposition can be expressed graphically as sets of overlapping classes in a multidimensional space of measured elemental intensities. To discriminate between classes of various materials, decision-tree and pattern recognition algorithms were studied. Results of application of these methods to data sets obtained for a pulsed 14-MeV neutron generator based active interrogation system are discussed.

  19. Atomization efficiency and photon yield in laser-induced breakdown spectroscopy analysis of single nanoparticles in an optical trap

    Science.gov (United States)

    Purohit, Pablo; Fortes, Francisco J.; Laserna, J. Javier

    2017-04-01

    Laser-induced breakdown spectroscopy (LIBS) was employed for investigating the influence of particle size on the dissociation efficiency and the absolute production of photons per mass unit of airborne solid graphite spheres under single-particle regime. Particles of average diameter of 400 nm were probed and compared with 2 μm particles. Samples were first catapulted into aerosol form and then secluded in an optical trap set by a 532 nm laser. Trap stability was quantified before subjecting particles to LIBS analysis. Fine alignment of the different lines comprising the optical catapulting-optical trapping-laser-induced breakdown spectroscopy instrument and tuning of excitation parameters conditioning the LIBS signal such as fluence and acquisition delay are described in detail with the ultimate goal of acquiring clear spectroscopic data on masses as low as 75 fg. The atomization efficiency and the photon yield increase as the particle size becomes smaller. Time-resolved plasma imaging studies were conducted to elucidate the mechanisms leading to particle disintegration and excitation.

  20. Displacement damage analysis and modified electrical equivalent circuit for electron and photon-irradiated silicon solar cells

    Science.gov (United States)

    Arjhangmehr, Afshin; Feghhi, Seyed Amir Hossein

    2014-10-01

    Solar modules and arrays are the conventional energy resources of space satellites. Outside the earth's atmosphere, solar panels experience abnormal radiation environments and because of incident particles, photovoltaic (PV) parameters degrade. This article tries to analyze the electrical performance of electron and photon-irradiated mono-crystalline silicon (mono-Si) solar cells. PV cells are irradiated by mono-energetic electrons and poly-energetic photons and immediately characterized after the irradiation. The mean degradation of the maximum power (Pmax) of silicon solar cells is presented and correlated using the displacement damage dose (Dd) methodology. This method simplifies evaluation of cell performance in space radiation environments and produces a single characteristic curve for Pmax degradation. Furthermore, complete analysis of the results revealed that the open-circuit voltage (Voc) and the filling factor of mono-Si cells did not significantly change during the irradiation and were independent of the radiation type and fluence. Moreover, a new technique is developed that adapts the irradiation-induced effects in a single-cell equivalent electrical circuit and adjusts its elements. The "modified circuit" is capable of modeling the "radiation damage" in the electrical behavior of mono-Si solar cells and simplifies the designing of the compensation circuits.

  1. Two-photon processes in highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Jahrsetz, Thorsten

    2015-03-05

    Two-photon processes are atomic processes in which an atom interacts simultaneously with two photons. Such processes describe a wide range of phenomena, such as two-photon decay and elastic or inelastic scattering of photons. In recent years two-photon processes involving highly charged heavy ions have become an active area of research. Such studies do not only consider the total transition or scattering rates but also their angular and polarization dependence. To support such examinations in this thesis I present a theoretical framework to describe these properties in all two-photon processes with bound initial and final states and involving heavy H-like or He-like ions. I demonstrate how this framework can be used in some detailed studies of different two-photon processes. Specifically a detailed analysis of two-photon decay of H-like and He-like ions in strong external electromagnetic fields shows the importance of considering the effect of such fields for the physics of such systems. Furthermore I studied the elastic Rayleigh as well as inelastic Raman scattering by heavy H-like ions. I found a number of previously unobserved phenomena in the angular and polarization dependence of the scattering cross-sections that do not only allow to study interesting details of the electronic structure of the ion but might also be useful for the measurement of weak physical effects in such systems.

  2. Focusing analysis of a complex photonic crystal slab with negative refraction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.-W.; Wu, M.-L. [Department of Mechanical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Chen, L.-W., E-mail: chenlw@mail.ncku.edu.t [Department of Mechanical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China)

    2010-10-01

    The electromagnetic wave propagation in a two-dimensional (2D) complex triangular photonic crystal (PC) consisting of dielectric cylinders of different radii in air is investigated. The plane wave expansion (PWE) and finite element (FE) methods are used to study the optical and focusing properties of the complex PC. Interestingly, in contrast to a triangular PC consisting of dielectric cylinders of the same radius, the complex PC can generate a focusing effect with an effective refractive index of -1. Furthermore, a design is proposed using antireflection structures to enhance the transmission efficiency of light at the interfaces between the air and the PC slab. Numerical simulations show that appropriately adding antireflection structures to the surface of the slab can greatly improve the focusing resolution.

  3. Analysis and synthesis of one-dimensional magneto-photonic crystals using coupled mode theory

    Science.gov (United States)

    Saghirzadeh Darki, Behnam; Nezhad, Abolghasem Zeidaabadi; Firouzeh, Zaker Hossein

    2017-03-01

    We utilize our previously developed temporal coupled mode approach to investigate the performance of one-dimensional magneto-photonic crystals (MPCs). We analytically demonstrate that a double-defect MPC provides adequate degrees of freedom to design a structure for arbitrary transmittance and Faraday rotation. By using our developed analytic approach along with the numerical transfer matrix method, we present a procedure for the synthesis of an MPC to generate any desired transmittance and Faraday rotation in possible ranges. However it is seen that only discrete values of transmittance and Faraday rotation are practically obtainable. To remedy this problem along with having short structures, we introduce a class of MPC heterostructures which are combinations of stacks with high and low optical contrast ratios.

  4. Analysis of photon count data from single-molecule fluorescence experiments

    Energy Technology Data Exchange (ETDEWEB)

    Burzykowski, T.; Szubiakowski, J.; Ryden, T

    2003-03-15

    We consider single-molecule fluorescence experiments with data in the form of counts of photons registered over multiple time-intervals. Based on the observation schemes, linking back to works by Dehmelt [Bull. Am. Phys. Soc. 20 (1975) 60] and Cook and Kimble [Phys. Rev. Lett. 54 (1985) 1023], we propose an analytical approach to the data based on the theory of Markov-modulated Poisson processes (MMPP). In particular, we consider maximum-likelihood estimation. The method is illustrated using a real-life dataset. Additionally, the properties of the proposed method are investigated through simulations and compared to two other approaches developed by Yip et al. [J. Phys. Chem. A 102 (1998) 7564] and Molski [Chem. Phys. Lett. 324 (2000) 301].

  5. Noise analysis in photonic true time delay systems based on broadband optical source and dispersion components.

    Science.gov (United States)

    Xue, Xiaoxiao; Wen, He; Zheng, Xiaoping; Zhang, Hanyi; Guo, Yili; Zhou, Bingkun

    2009-02-01

    The noise in photonic true time delay systems based on broadband optical source and dispersion components is investigated. It is found that the beat noise induced by the optical source begins to dominate and grows far larger than other noise terms quickly, as long as the detected optical power is above some certain value P(thr). When the system dispersion is nonzero, the output carrier-to-noise ratio (CNR) will change periodically with the optical bandwidth due to the noise power increment and the dispersion induced radio frequency signal power degradation. The maximum CNR is the peak value of the first period. For a set of specified system conditions, the P(thr) is calculated to be -21 dBm, and the optimal optical bandwidth is 0.8 nm, at which the maximum CNR is 93.3 dB by considering the noise in a 1 Hz bandwidth. The results are verified experimentally.

  6. Performance and capacity analysis of Poisson photon-counting based Iter-PIC OCDMA systems.

    Science.gov (United States)

    Li, Lingbin; Zhou, Xiaolin; Zhang, Rong; Zhang, Dingchen; Hanzo, Lajos

    2013-11-04

    In this paper, an iterative parallel interference cancellation (Iter-PIC) technique is developed for optical code-division multiple-access (OCDMA) systems relying on shot-noise limited Poisson photon-counting reception. The novel semi-analytical tool of extrinsic information transfer (EXIT) charts is used for analysing both the bit error rate (BER) performance as well as the channel capacity of these systems and the results are verified by Monte Carlo simulations. The proposed Iter-PIC OCDMA system is capable of achieving two orders of magnitude BER improvements and a 0.1 nats of capacity improvement over the conventional chip-level OCDMA systems at a coding rate of 1/10.

  7. Synthetic oligomer analysis using atmospheric pressure photoionization mass spectrometry at different photon energies.

    Science.gov (United States)

    Desmazières, Bernard; Legros, Véronique; Giuliani, Alexandre; Buchmann, William

    2014-01-15

    Atmospheric pressure photoionization (APPI) followed by mass spectrometric detection was used to ionize a variety of polymers: polyethylene glycol, polymethyl methacrylate, polystyrene, and polysiloxane. In most cases, whatever the polymer or the solvent used (dichloromethane, tetrahydrofuran, hexane, acetone or toluene), only negative ion mode produced intact ions such as chlorinated adducts, with no or few fragmentations, in contrast to the positive ion mode that frequently led to important in-source fragmentations. In addition, it was shown that optimal detection of polymer distributions require a fine tuning of other source parameters such as temperature and ion transfer voltage. Series of mass spectra were recorded in the negative mode, in various solvents (dichloromethane, tetrahydrofuran, hexane, toluene, and acetone), by varying the photon energy from 8eV up to 10.6eV using synchrotron radiation. To these solvents, addition of a classical APPI dopant (toluene or acetone) was not necessary. Courtesy of the synchrotron radiation, it was demonstrated that the photon energy required for an efficient ionization of the polymer was correlated to the ionization energy of the solvent. As commercial APPI sources typically use krypton lamps with energy fixed at 10eV and 10.6eV, the study of the ionization of polymers over a wavelength range allowed to confirm and refine the previously proposed ionization mechanisms. Moreover, the APPI source can efficiently be used as an interface between size exclusion chromatography or reverse phase liquid chromatography and MS for the study of synthetic oligomers. However, the photoionization at fixed wavelength of polymer standards with different molecular weights showed that it was difficult to obtain intact ionized oligomers with molecular weights above a few thousands.

  8. Conference on Instrumental Activation Analysis: IAA 89

    Science.gov (United States)

    Vobecky, M.; Obrusnik, I.

    1989-05-01

    The proceedings contain 40 abstracts of papers all of which have been incorporated in INIS. The papers were centred on the applications of radioanalytical methods, especially on neutron activation analysis, x ray fluorescence analysis, PIXE analysis and tracer techniques in biology, medicine and metallurgy, measuring instruments including microcomputers, and data processing methods.

  9. Hallo photons calls photon; Allo photon appelle photon

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1997-09-01

    When a pair of photons is created, it seems that these 2 photons are bound together by a mysterious link. This phenomenon has been discovered at the beginning of the seventies. In this new experiment the 2 photons are separated and have to follow different ways through optic cables until they face a quantum gate. At this point they have to chose between a short and a long itinerary. Statistically they have the same probability to take either. In all cases the 2 photons agree to do the same choice even if the 2 quantum gates are distant of about 10 kilometers. Some applications in ciphering and coding of messages are expected. (A.C.)

  10. Statistical analysis of the limitation of half integer resonances on the available momentum acceptance of the High Energy Photon Source

    Science.gov (United States)

    Jiao, Yi; Duan, Zhe

    2017-01-01

    In a diffraction-limited storage ring, half integer resonances can have strong effects on the beam dynamics, associated with the large detuning terms from the strong focusing and strong sextupoles as required for an ultralow emittance. In this study, the limitation of half integer resonances on the available momentum acceptance (MA) was statistically analyzed based on one design of the High Energy Photon Source (HEPS). It was found that the probability of MA reduction due to crossing of half integer resonances is closely correlated with the level of beta beats at the nominal tunes, but independent of the error sources. The analysis indicated that for the presented HEPS lattice design, the rms amplitude of beta beats should be kept below 1.5% horizontally and 2.5% vertically to reach a small MA reduction probability of about 1%.

  11. Use of fuzzy edge single-photon emission computed tomography analysis in definite Alzheimer's disease - a retrospective study

    Directory of Open Access Journals (Sweden)

    Rusina Robert

    2010-09-01

    Full Text Available Abstract Background Definite Alzheimer's disease (AD requires neuropathological confirmation. Single-photon emission computed tomography (SPECT may enhance diagnostic accuracy, but due to restricted sensitivity and specificity, the role of SPECT is largely limited with regard to this purpose. Methods We propose a new method of SPECT data analysis. The method is based on a combination of parietal lobe selection (as regions-of-interest (ROI, 3D fuzzy edge detection, and 3D watershed transformation. We applied the algorithm to three-dimensional SPECT images of human brains and compared the number of watershed regions inside the ROI between AD patients and controls. The Student's two-sample t-test was used for testing domain number equity in both groups. Results AD patients had a significantly reduced number of watershed regions compared to controls (p Conclusions Our non-invasive, relatively low-cost, and easy method can contribute to a more precise diagnosis of AD.

  12. Photon generator

    Science.gov (United States)

    Srinivasan-Rao, Triveni

    2002-01-01

    A photon generator includes an electron gun for emitting an electron beam, a laser for emitting a laser beam, and an interaction ring wherein the laser beam repetitively collides with the electron beam for emitting a high energy photon beam therefrom in the exemplary form of x-rays. The interaction ring is a closed loop, sized and configured for circulating the electron beam with a period substantially equal to the period of the laser beam pulses for effecting repetitive collisions.

  13. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2013-01-01

    Microwave photonics continues to see rapid growth. The integration of optical fiber and wireless networks has become a commercial reality and is becoming increasingly pervasive. Such hybrid technology will lead to many innovative applications, including backhaul solutions for mobile networks and ultrabroadband wireless networks that can provide users with very high bandwidth services. Microwave Photonics, Second Edition systematically introduces important technologies and applications in this emerging field. It also reviews recent advances in micro- and millimeter-wavelength and terahertz-freq

  14. Photonic lanterns

    Science.gov (United States)

    Leon-Saval, Sergio G.; Argyros, Alexander; Bland-Hawthorn, Joss

    2013-12-01

    Multimode optical fibers have been primarily (and almost solely) used as "light pipes" in short distance telecommunications and in remote and astronomical spectroscopy. The modal properties of the multimode waveguides are rarely exploited and mostly discussed in the context of guiding light. Until recently, most photonic applications in the applied sciences have arisen from developments in telecommunications. However, the photonic lantern is one of several devices that arose to solve problems in astrophotonics and space photonics. Interestingly, these devices are now being explored for use in telecommunications and are likely to find commercial use in the next few years, particularly in the development of compact spectrographs. Photonic lanterns allow for a low-loss transformation of a multimode waveguide into a discrete number of single-mode waveguides and vice versa, thus enabling the use of single-mode photonic technologies in multimode systems. In this review, we will discuss the theory and function of the photonic lantern, along with several different variants of the technology. We will also discuss some of its applications in more detail. Furthermore, we foreshadow future applications of this technology to the field of nanophotonics.

  15. Spatially Resolved Elemental Analysis, Spectroscopy and Diffraction at the GSECARS Sector at the Advanced Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, Stephen R.; Lanzirotti, Antonio; Newville, Matthew; Rivers, Mark L.; Eng, Peter; Lefticariu, Liliana

    2017-01-01

    X-ray microprobes (XRM) coupled with high-brightness synchrotron X-ray facilities are powerful tools for environmental biogeochemistry research. One such instrument, the XRM at the Geo Soil Enviro Center for Advanced Radiation Sources Sector 13 at the Advanced Photon Source (APS; Argonne National Laboratory, Lemont, IL) was recently improved as part of a canted undulator geometry upgrade of the insertion device port, effectively doubling the available undulator beam time and extending the operating energy of the branch supporting the XRM down to the sulfur K edge (2.3 keV). Capabilities include rapid, high-resolution, elemental imaging including fluorescence microtomography, microscale X-ray absorption fine structure spectroscopy including sulfur K edge capability, and microscale X-ray diffraction. These capabilities are advantageous for (i) two-dimensional elemental mapping of relatively large samples at high resolution, with the dwell times typically limited only by the count times needed to obtain usable counting statistics for low concentration elements, (ii) three-dimensional imaging of internal elemental distributions in fragile hydrated specimens, such as biological tissues, avoiding the need for physical slicing, (iii) spatially resolved speciation determinations of contaminants in environmental materials, and (iv) identification of contaminant host phases. In this paper, we describe the XRM instrumentation, techniques, applications demonstrating these capabilities, and prospects for further improvements associated with the proposed upgrade of the APS.

  16. Thermal distribution analysis of multi-core photonic crystal fiber laser

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yi-bo; YAO Jian-quan; ZHANG Lei; WANG Yuan; WEN Wu-qi; JING Lei; DI Zhi-gang; KANG Jian-yi

    2012-01-01

    The thermal properties of photonic crystal fiber (PCF) laser with 18 circularly distributed cores are investigated by using full-vector finite element method (FEM).The results show that the 18-core PCF has a more effective thermal dispersion construction compared with the single core PCF and 19-core PCF.In addition,the temperature distribution of 18-core PCF laser with different thermal loads is simulated.The results show that the core temperature approaches the fiber drawing value of 1800 K approximately when the thermal load is above 80 W/m which corresponds to the pumping power of 600 W approximately,while the coating temperature approaches the damage value of about 550 K when the thermal load is above 15 W/m which corresponds to the pumping power of 110 W approximately.Therefore the fiber cooling is necessary to achieve power scaling.Compared with other different cooling systems,the copper cooling scheme is found to be an effective method to reduce the thermal effects.

  17. Alpha hemolysin induces an increase of erythrocytes calcium: a FLIM 2-photon phasor analysis approach.

    Directory of Open Access Journals (Sweden)

    Susana Sanchez

    Full Text Available α-Hemolysin (HlyA from Escherichia coli is considered as the prototype of a family of toxins called RTX (repeat in toxin, a group of proteins that share genetic and structural features. HlyA is an important virulence factor in E. coli extraintestinal infections, such as meningitis, septicemia and urinary infections. High concentrations of the toxin cause the lysis of several cells such as erythrocytes, granulocytes, monocytes, endothelial and renal epithelial cells of different species. At low concentrations it induces the production of cytokines and apoptosis. Since many of the subcytolytic effects in other cells have been reported to be triggered by the increase of intracellular calcium, we followed the calcium concentration inside the erythrocytes while incubating with sublytic concentrations of HlyA. Calcium concentration was monitored using the calcium indicator Green 1, 2-photon excitation, and fluorescence lifetime imaging microscopy (FLIM. Data were analyzed using the phasor representation. In this report, we present evidence that, at sublytic concentrations, HlyA induces an increase of calcium concentration in rabbit erythrocytes in the first 10 s. Results are discussed in relation to the difficulties of measuring calcium concentrations in erythrocytes where hemoglobin is present, the contribution of the background and the heterogeneity of the response observed in individual cells.

  18. Analysis of ionic mobilities in liquid isooctane with low dose radiotherapy pulsed photon beams

    Science.gov (United States)

    Pardo-Montero, J.; Tegami, S.; Gago-Arias, A.; González-Castaño, D. M.; Holzscheiter, M. H.; Gómez, F.

    2012-09-01

    In this work we present a model of signal temporal development in ionization chambers and we use it to determine ionic mobilities and relative densities of charge carriers in non-ultrapure liquid isooctane using a liquid-filled ionization chamber dosimeter. The detector has been irradiated with a low dose rate, short pulsed photon beam generated with a medical LINAC. Ionic mobilities have been obtained by studying the temporal development of the readout signal and fitting it to a model for low dose rate beams where recombination is negligible. The best fit has been obtained for 3 ionic species with mobilities k1 = (2.22±0.22) × 10-8, k2 = (3.37±0.43) × 10-8, k3 = (19.69±2.59) × 10-8 m2 V-1 s-1 and relative densities n1 = 0.5 (n1 is not a fitting parameter), n2 = 0.23±0.03 and n3 = 0.27±0.03.

  19. Polarization properties of photonic bandgap fibers

    DEFF Research Database (Denmark)

    Broeng, Jes; Libori, Stig E. Barkou; Bjarklev, Anders Overgaard

    2000-01-01

    We present the first analysis of polarization properties of photonic bandgap fibers. Strong birefringence may be obtained for modest non-uniformities in and around the core region, suggesting the use of photonic bandgap fibers as polarization maintaining components.......We present the first analysis of polarization properties of photonic bandgap fibers. Strong birefringence may be obtained for modest non-uniformities in and around the core region, suggesting the use of photonic bandgap fibers as polarization maintaining components....

  20. All-photonic quantum repeaters

    Science.gov (United States)

    Azuma, Koji; Tamaki, Kiyoshi; Lo, Hoi-Kwong

    2015-01-01

    Quantum communication holds promise for unconditionally secure transmission of secret messages and faithful transfer of unknown quantum states. Photons appear to be the medium of choice for quantum communication. Owing to photon losses, robust quantum communication over long lossy channels requires quantum repeaters. It is widely believed that a necessary and highly demanding requirement for quantum repeaters is the existence of matter quantum memories. Here we show that such a requirement is, in fact, unnecessary by introducing the concept of all-photonic quantum repeaters based on flying qubits. In particular, we present a protocol based on photonic cluster-state machine guns and a loss-tolerant measurement equipped with local high-speed active feedforwards. We show that, with such all-photonic quantum repeaters, the communication efficiency scales polynomially with the channel distance. Our result paves a new route towards quantum repeaters with efficient single-photon sources rather than matter quantum memories. PMID:25873153

  1. Photonic crystal fibers in biophotonics

    Science.gov (United States)

    Tuchin, Valery V.; Skibina, Julia S.; Malinin, Anton V.

    2011-12-01

    We observed recent experimental results in area of photonic crystal fibers appliance. Possibility of creation of fiberbased broadband light sources for high resolution optical coherence tomography is discussed. Using of femtosecond pulse laser allows for generation of optical radiation with large spectral width in highly nonlinear solid core photonic crystal fibers. Concept of exploitation of hollow core photonic crystal fibers in optical sensing is demonstrated. The use of photonic crystal fibers as "smart cuvette" gives rise to efficiency of modern optical biomedical analysis methods.

  2. Mesoscopic photon heat transistor

    DEFF Research Database (Denmark)

    Ojanen, T.; Jauho, Antti-Pekka

    2008-01-01

    We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir-Wingreen-Landauer-typ......We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir......-Wingreen-Landauer-type of conductance formula, which gives the photonic heat current through an arbitrary circuit element coupled to two dissipative reservoirs at finite temperatures. As an illustration we present an exact solution for the case when the intermediate circuit can be described as an electromagnetic resonator. We discuss...

  3. Activation analysis of meteorites. 3

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, H.; Honda, M.; Sato, H. [Nihon Univ., College of Humanities and Sciences, Tokyo (Japan); Ebihara, M.; Oura, Y.; Setoguchi, M. [Tokyo Metropolitan Univ., Faculty of Science, Tokyo (Japan)

    2001-07-01

    A long-lived cosmogenic nuclide, {sup 53}Mn in extra-terrestrial materials has been determined in the DR-1 hole of the JRR-3M reactor, applying the well-thermalized neutron flux. The neutron flux intensities are variable with the depths whereas the fast thermal ratios are not quite variable. By this method, {sup 53}Mn contents in iron meteorites and metal phases in general could be routinely determined in many samples. The chemical separation method has been modified and a convenient short circuit method has been proposed to shorten the process. The short method is to count the activities of {sup 54}Mn just after the irradiation without further purification of manganese. (author)

  4. Photonic Crystal Surfaces as a General Purpose Platform for Label-Free and Fluorescent Assays.

    Science.gov (United States)

    Cunningham, Brian T

    2010-04-01

    Photonic crystal surfaces can be designed to provide a wide range of functions that are used to perform biochemical and cell-based assays. Detection of the optical resonant reflections from photonic crystal surfaces enables high sensitivity label-free biosensing, while the enhanced electromagnetic fields that occur at resonant wavelengths can be used to enhance the detection sensitivity of any surface-based fluorescence assay. Fabrication of photonic crystals from inexpensive plastic materials over large surface areas enables them to be incorporated into standard formats that include microplates, microarrays, and microfluidic channels. This report reviews the design of photonic crystal biosensors, their associated detection instrumentation, and biological applications. Applications including small molecule high throughput screening, cell membrane integrin activation, gene expression analysis, and protein biomarker detection are highlighted. Recent results in which photonic crystal surfaces are used for enhancing the detection of Surface-Enhanced Raman Spectroscopy, and the development of high resolution photonic crystal-based laser biosensors are also described.

  5. The Study of Electromagnetic Wave Propogation in Photonic Crystals Via Planewave Based Transfer (Scattering) Matrix Method with Active Gain Material Applications

    Energy Technology Data Exchange (ETDEWEB)

    LI, Ming [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    In this dissertation, a set of numerical simulation tools are developed under previous work to efficiently and accurately study one-dimensional (1D), two-dimensional(2D), 2D slab and three-dimensional (3D) photonic crystal structures and their defects effects by means of spectrum (transmission, reflection, absorption), band structure (dispersion relation), and electric and/or magnetic fields distribution (mode profiles). Furthermore, the lasing property and spontaneous emission behaviors are studied when active gain materials are presented in the photonic crystal structures. Various physical properties such as resonant cavity quality factor, waveguide loss, propagation group velocity of electromagnetic wave and light-current curve (for lasing devices) can be obtained from the developed software package.

  6. The study of electromagnetic wave propagation in photonic crystals via planewave based transfer (scattering) matrix method with active gain material applications

    Science.gov (United States)

    Li, Ming

    In this dissertation, a set of numerical simulation tools are developed under previous work to efficiently and accurately study one-dimensional (1D), two-dimensional (2D), 2D slab and three-dimensional (3D) photonic crystal structures and their defects effects by means of spectrum (transmission, reflection, absorption), band structure (dispersion relation), and electric and/or magnetic fields distribution (mode profiles). Further more, the lasing property and spontaneous emission behaviors are studied when active gain materials are presented in the photonic crystal structures. First, the planewave based transfer (scattering) matrix method (TMM) is described in every detail along with a brief review of photonic crystal history (Chapter 1 and 2). As a frequency domain method, TMM has the following major advantages over other numerical methods: (1) the planewave basis makes Maxwell's Equations a linear algebra problem and there are mature numerical package to solve linear algebra problem such as Lapack and Scalapack (for parallel computation). (2) Transfer (scattering) matrix method make 3D problem into 2D slices and link all slices together via the scattering matrix (S matrix) which reduces computation time and memory usage dramatically and makes 3D real photonic crystal devices design possible; and this also makes the simulated domain no length limitation along the propagation direction (ideal for waveguide simulation). (3) It is a frequency domain method and calculation results are all for steady state, without the influences of finite time span convolution effects and/or transient effects. (4) TMM can treat dispersive material (such as metal at visible light) naturally without introducing any additional computation; and meanwhile TMM can also deal with anisotropic material and magnetic material (such as perfectly matched layer) naturally from its algorithms. (5) Extension of TMM to deal with active gain material can be done through an iteration procedure with gain

  7. Neutron Activation Analysis of Water - A Review

    Science.gov (United States)

    Buchanan, John D.

    1971-01-01

    Recent developments in this field are emphasized. After a brief review of basic principles, topics discussed include sources of neutrons, pre-irradiation physical and chemical treatment of samples, neutron capture and gamma-ray analysis, and selected applications. Applications of neutron activation analysis of water have increased rapidly within the last few years and may be expected to increase in the future.

  8. The photon PDF of the proton

    CERN Document Server

    Martin, A D

    2014-01-01

    We show how the photon input parton distribution function (PDF) may be calculated with good accuracy, and used in an extended DGLAP global parton analysis in which the photon is treated as an additional point-like parton. The uncertainty of the input photon PDF is relatively small, since the major part of the distribution (which is produced by the coherent emission of the photon from a proton that remains intact) is well known. We present the expected photon PDFs, and compare the predictions with ZEUS data for isolated photon electroproduction at negative rapidities.

  9. Photonic crystals principles and applications

    CERN Document Server

    Gong, Qihuang

    2013-01-01

    IntroductionPrimary Properties of Photonic CrystalsFabrication of Photonic CrystalsPhotonic Crystal All-Optical SwitchingTunable Photonic Crystal FilterPhotonic Crystal LaserPhotonic Crystal Logic DevicesPhotonic Crystal Sensors

  10. Photonic Bandgaps in Photonic Molecules

    Science.gov (United States)

    Smith, David D.; Chang, Hongrok; Gates, Amanda L.; Fuller, Kirk A.; Gregory, Don A.; Witherow, William K.; Paley, Mark S.; Frazier, Donald O.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    This talk will focus on photonic bandgaps that arise due to nearly free photon and tight-binding effects in coupled microparticle and ring-resonator systems. The Mie formulation for homogeneous spheres is generalized to handle core/shell systems and multiple concentric layers in a manner that exploits an analogy with stratified planar systems, thereby allowing concentric multi-layered structures to be treated as photonic bandgap (PBG) materials. Representative results from a Mie code employing this analogy demonstrate that photonic bands arising from nearly free photon effects are easily observed in the backscattering, asymmetry parameter, and albedo for periodic quarter-wave concentric layers, though are not readily apparent in extinction spectra. Rather, the periodicity simply alters the scattering profile, enhancing the ratio of backscattering to forward scattering inside the bandgap, in direct analogy with planar quarter-wave multilayers. PBGs arising from tight-binding may also be observed when the layers (or rings) are designed such that the coupling between them is weak. We demonstrate that for a structure consisting of N coupled micro-resonators, the morphology dependent resonances split into N higher-Q modes, in direct analogy with other types of oscillators, and that this splitting ultimately results in PBGs which can lead to enhanced nonlinear optical effects.

  11. Evaluation of dilated cardiomyopathy by /sup 201/Tl myocardial single photon emission computed tomography. Morphological and quantitative analysis

    Energy Technology Data Exchange (ETDEWEB)

    Futagami, Yasuo; Makino, Katsutoshi; Ichikawa, Takehiko

    1984-08-01

    To estimate dilated cardiomyopathy (DCM)morphologically and quantitatively, /sup 201/Tl myocardial single photon emission computed tomography (SPECT) was performed in 14 DCM and 5 normal cases. Using a rotating dual-gamma camera system, resting SPECT data were collected for 6 minutes. Quantitative analysis of clinical cases was based on phantom studies. Marked spherical left ventricular (LV) dilatation (14/14), localized-diffuse low uptake or defect (12/14), and right ventricular visualization (6/14) were characteristic features in DCM. Differentiation of DCM from ischemic heart disease by SPECT was possible through the feature indicating disproportionately large LV cavity to defect size or degree. Quantitative analysis When DCM was compared with normal control (n-5), following 3 features were impressive: DCM was significantly higher in LV myocardial /sup 201/Tl uptake ratio and LV volume than normal control; DCM was significantly lower in LV myocardial /sup 201/Tl uptake ratio of unit volume (1 ml) than normal control; DCM was significantly lower in mean myocardial count/mean lung count.ratio than normal control.

  12. Photon physics with PHENIX

    Energy Technology Data Exchange (ETDEWEB)

    White, S. [Brookhaven National Lab., Upton, NY (United States)

    1995-07-15

    In this Paper the author discusses briefly the physics motivation for extending measurements of particle production with high granularity and particle id capabilities to neutrals in PHENIX. The author then discusses the technique of direct photon measurement in the presence of copious background photons from {pi}{sup o} decays. The experiment will measure relatively low p{sub t} photons near y=0 in the lab frame. This new experimental environment of high multiplicity and low {gamma} momenta will affect both the techniques used and the type of analysis which can be performed. The Phenix Electromagnetic calorimeter is described and its capabilities illustrated with results from simulation and beam tests of the first production array.

  13. Photon differentials

    DEFF Research Database (Denmark)

    Schjøth, Lars; Revall Frisvad, Jeppe; Erleben, Kenny;

    2007-01-01

    illumination features. This is often not desirable as these may lose clarity or vanish altogether. We present an accurate method for reconstruction of indirect illumination with photon mapping. Instead of reconstructing illumination using classic density estimation on finite points, we use the correlation...

  14. Two-order Interference of Single Photon

    Institute of Scientific and Technical Information of China (English)

    JIANG Yunkun; LI Jian; SHI Baosen; FAN Xiaofeng; GUO Guangcan

    2000-01-01

    A pair of photons called signal and idler photons, respectively, are produced through the nonlinear process of type-I spontaneous parametric downconversion in BBO crystal pumped by the second-harmonic wave of a Ti:sapphire femtosecond laser pulse. The two-order interference phenomenon of the signal photon in Michelson interferometer is observed and give an analysis in detail.

  15. National photonics skills standards for technicians

    Science.gov (United States)

    Hull, Darrell M.

    1995-10-01

    Photonics is defined as the generation, manipulation, transport, detection, and use of light information and energy whose quantum unit is the photon. The range of applications of phonics extends from energy generation to detection to communication and information processing. Photonics is at the heart of today's communication systems, from the laser that generates the digital information transported along a fiber- optic cable to the detector that decodes the information. Whether the transmitted information is a phone call from across the street or across the globe, photonics brings it to you. Where your health is concerned, photonics allows physicians to do minimally invasive surgery using fiber-optic endoscopes and lasers. Researches using spectroscopy and microscopy are pushing the frontiers of biotechnology in activities as widespread as diagnosing disease and probing the mysteries of the genetic code. Advanced sensing and imaging techniques monitor the environment, gathering data on crops and forests, analyzing the ocean's currents and contents, and probing the atmosphere of pollutants. Transportation needs are being impacted by photonic sensors and laser rangefinders that will soon monitor and control the traffic on our nation's highways. In our factories, photonics provides machine vision systems that give a level of quality control human inspectors could never achieve. In manufacturing, lasers are replacing a variety of cutting, welding, and marking techniques, while imaging systems teamed with neural networks are producing intelligent robots. In short, photonics is paving our way into the new millennium. The skill standard is intended to define the knowledge and capabilities - the skills - that workers in the phonics industry need. Phonics will be one of the primary battlefields of the world economic conflict, and it is imperative that U.S. photonics technicians be skilled enough to allow the United States to remain competitive in a global marketplace. The

  16. Characterization and Analysis of Integrated Silicon Photonic Detectors for High-Speed Communications

    Science.gov (United States)

    2015-03-26

    devices. This document describes the characterization and analysis of inte- grated photodiodes for digital and analog applications. The photodiode is...50 LCR inductance , capacitance, and resistance . . . . . . . . . . . . . . . . . . . . . . . 52 TE transverse electric...application for the high-bandwidth capability of integrated pho- tonic systems, could be used for analog antenna remoting. By up-converting to a high

  17. Light-Front Quark Model Analysis of Meson-Photon Transition Form Factor

    CERN Document Server

    Choi, Ho-Meoyng

    2016-01-01

    We discuss $(\\pi^0,\\eta,\\eta')\\to\\gamma^*\\gamma$ transition form factors using the light-front quark model. Our discussion includes the analysis of the mixing angles for $\\eta-\\eta'$. Our results for $Q^2 F_{(\\pi^0,\\eta,\\eta')\\to\\gamma^*\\gamma}(Q^2)$ show scaling behavior for high $Q^2$ consistent with pQCD predictions.

  18. LightForce Photon-Pressure Collision Avoidance: Updated Efficiency Analysis Utilizing a Highly Parallel Simulation Approach

    Science.gov (United States)

    Stupl, J.; Faber, N.; Foster, C.; Yang, F.; Nelson, B.; Aziz, J.; Nuttall, A.; Henze, C.; Levit, C.

    2014-09-01

    This paper provides an updated efficiency analysis of the LightForce space debris collision avoidance scheme. LightForce aims to prevent collisions on warning by utilizing photon pressure from ground based, commercial off the shelf lasers. Past research has proven that a few ground-based systems consisting of 10 kW class lasers directed by 1.5 m telescopes with adaptive optics could lower the expected number of collisions in Low Earth Orbit (LEO) by an order of magnitude. Our simulation approach utilizes the entire Two Line Element (TLE) catalogue in LEO for a given day as initial input. Least-squares fitting of a TLE time series is used for an improved orbit estimate. We then calculate the probability of collision for all LEO objects in the catalogue for a time step of the simulation. The conjunctions that exceed a threshold probability of collision are then engaged by a simulated network of laser ground stations. After those engagements, the perturbed orbits are used to re-assess the probability of collision and evaluate the efficiency. This paper describes new simulations with three updated aspects: 1) By utilizing a highly parallel simulation approach employing hundreds of processors, we have extended our analysis to a much broader dataset. The simulation time is extended to one year. 2) We analyze not only the efficiency of LightForce on conjunctions that naturally occur, but also take into account conjunctions caused by orbit perturbations due to LightForce engagements. 3) We use a new simulation approach that is regularly updating the LightForce engagement strategy, as it would be during actual operations. In this paper we present both our simulation approach to parallelize the efficiency analysis, its computational performance and the resulting expected efficiency of the LightForce collision avoidance system.

  19. Bio-photonic detection method for morphological analysis of anthracnose disease and physiological disorders of Diospyros kaki

    Science.gov (United States)

    Wijesinghe, Ruchire Eranga; Lee, Seung-Yeol; Ravichandran, Naresh Kumar; Shirazi, Muhammad Faizan; Moon, Byungin; Jung, Hee-Young; Jeon, Mansik; Kim, Jeehyun

    2016-10-01

    The pathological and physiological defects in various types of fruits lead to large amounts of economical waste. It is well recognized that internal fruit defects due to pathological infections and physiological disorders can be effectively visualized at an initial stage of the disease using a well-known bio-photonic detection method called optical coherence tomography (OCT). This work investigates the use of OCT for identifying the morphological variations of anthracnose (bitter rot) disease infected and physiologically disordered Diospyros kaki (Asian Persimmon) fruits. An experiment was conducted using fruit samples that were carefully selected from persimmon orchards. Depth-resolved images with a high axial resolution were acquired using 850-nm-based spectral-domain OCT (SD-OCT) system. The obtained exemplary high-resolution two-dimensional and volumetric three-dimensional images revealed complementary morphological differences between healthy and defected samples. Moreover, the obtained depth-profile analysis results confirmed the disappearance of the healthy cell layers among the healthy-infected boundary regions. Thus, the proposed method has the potential to increase the diagnostic accuracy of the OCT technique used in agricultural plantations.

  20. Eta photoproduction in a combined analysis of pion- and photon-induced reactions

    CERN Document Server

    Rönchen, D; Haberzettl, H; Haidenbauer, J; Meißner, U -G; Nakayama, K

    2015-01-01

    The $\\eta N$ final state is isospin-selective and thus provides access to the spectrum of excited nucleons without being affected by excited $\\Delta$ states. To this end, the world database on eta photoproduction off the proton up to $E\\sim 2.3$~GeV is analyzed, including data on differential cross sections, and single and double polarization observables. The resonance spectrum and its properties are determined in a combined analysis of eta and pion photoproduction off the proton together with the reactions $\\pi N\\to \\pi N$, $\\eta N$, $K\\Lambda$ and $K\\Sigma$. For the analysis, the so-called J\\"ulich coupled-channel framework is used, incorporating unitarity, analyticity, and effective three-body channels. Parameters tied to photoproduction and hadronic interactions are varied simultaneously. The influence of recent MAMI $T$ and $F$ asymmetry data in eta photoproduction is discussed in detail.

  1. Photon and fast neutron dosimetry using aluminium oxide thermoluminescence dosemeters.

    Science.gov (United States)

    Santos, J P; Fernandes, A C; Gonçalves, I C; Marques, J G; Carvalho, A F; Santos, L; Cardoso, J; Osvay, M

    2006-01-01

    Al(2)O(3):Mg,Y thermoluminescence (TL) dosemeters were used to measure photon and fast neutron doses in a fast neutron beam recently implemented at the Portuguese Research Reactor, Nuclear and Technological Institute, Portugal. The activation of Al(2)O(3):Mg,Y by fast neutrons provides information about the fast neutron component by measuring the activity of the reaction products and the self-induced TL signal. Additionally, the first TL reading after irradiation determines the photon dose. The elemental composition of the dosemeters was determined by instrumental neutron activation analysis and by particle induced X-ray emission. Results demonstrate that Al(2)O(3):Mg,Y is an adequate material to discriminate photon and fast neutron fields for reactor dosimetry purposes.

  2. Optical techniques in pulmonary medicine. SPIE photonics West.

    Science.gov (United States)

    Suter, Melissa J; Lam, Stephen; Brenner, Matthew

    2012-04-01

    There is ongoing interest in the emerging field of pulmonary photonic-based diagnostics. Potential clinical need areas that are being actively investigated at this time include airway and peripheral lung cancer diagnostics, pulmonary parenchymal and interstitial disorders, alveolar structure function, inhalation injury, ciliary function analysis, asthma and obstructive lung diseases.

  3. Refractive index sensing performance analysis of photonic crystal Mach-Zehnder interferometer based on BP neural network optimization

    Science.gov (United States)

    Chen, Ying; Liu, Teng; Wang, Wenyue; Zhu, Qiguang; Bi, Weihong

    2015-04-01

    According to the band gap and photon localization characteristics, the single-arm notching and the double-arm notching Mach-Zehnder interferometer (MZI) structures based on 2D triangular lattice air hole-typed photonic crystal waveguide are proposed. The back-propagation (BP) neural network is introduced to optimize the structural parameters of the photonic crystal MZI structure, which results in the normalized transmission peak increasing from 85.3% to 97.1%. The sensitivity performances of the two structures are compared and analyzed using the Salmonella solution samples with different concentrations in the numerical simulation. The results show that the sensitivity of the double-arm notching structure is 4583 nm/RIU, which is about 6.4 times of the single-arm notching structure, which can provide some references for the optimization of the photonic devices and the design of high-sensitivity biosensors.

  4. FDTD analysis of photonic quasicrystals with different tiling geometries and fabrication by single beam computer-generated holography

    CERN Document Server

    Zito, G; Santamato, E; Marino, A; Tkachenko, V; Abbate, G

    2013-01-01

    Multiple-beam holography has been widely used for the realization of photonic quasicrystals with high rotational symmetries not achievable by the conventional periodic crystals. Accurate control of the properties of the interfering beams is necessary to provide photonic band-gap structures. Here we show, by FDTD simulations of the transmission spectra of 8-fold quasiperiodic structures, how the geometric tiling of the structure affects the presence and properties of the photonic band-gap for low refractive index contrasts. Hence, we show an interesting approach to the fabrication of photonic quasicrystals based on the use of a programmable Spatial Light Modulator encoding Computer-Generated Holograms, that permits an accurate control of the writing pattern with almost no limitations in the pattern design. Using this single-beam technique we fabricated quasiperiodic structures with high rotational symmetries and different geometries of the tiling, demonstrating the great versatility of our technique.

  5. Analysis of the EBT3 Gafchromic film irradiated with 6 MV photons and 6 MeV electrons using reflective mode scanners.

    Science.gov (United States)

    Farah, Nicolas; Francis, Ziad; Abboud, Marie

    2014-09-01

    We explore in our study the effects of electrons and X-rays irradiations on the newest version of the Gafchromic EBT3 film. Experiments are performed using the Varian "TrueBeam 1.6" medical accelerator delivering 6 MV X-ray photons and 6 MeV electron beams as desired. The main interest is to compare the responses of EBT3 films exposed to two separate beams of electrons and photons, for radiation doses ranging up to 500 cGy. The analysis is done on a flatbed EPSON 10000 XL scanner and cross checked on a HP Scanjet 4850 scanner. Both scanners are used in reflection mode taking into account landscape and portrait scanning positions. After thorough verifications, the reflective scanning method can be used on EBT3 as an economic alternative to the transmission method which was also one of the goals of this study. A comparison is also done between single scan configuration including all samples in a single A4 (HP) or A3 (EPSON) format area and multiple scan procedure where each sample is scanned separately on its own. The images analyses are done using the ImageJ software. Results show significant influence of the scanning configuration but no significant differences between electron and photon irradiations for both single and multiple scan configurations. In conclusion, the film provides a reliable relative dose measurement method for electrons and photons irradiations in the medical field applications.

  6. Eigenmodal analysis of Anderson localization: Applications to photonic lattices and Bose-Einstein condensates

    Science.gov (United States)

    Ying, Guanwen; Kouzaev, Guennadi

    2016-10-01

    We present the eigenmodal analysis techniques enhanced towards calculations of optical and non-interacting Bose-Einstein condensate (BEC) modes formed by random potentials and localized by Anderson effect. The results are compared with the published measurements and verified additionally by the convergence criterion. In 2-D BECs captured in circular areas, the randomness shows edge localization of the high-order Tamm-modes. To avoid strong diffusive effect, which is typical for BECs trapped by speckle potentials, a 3-D-lattice potential with increased step magnitudes is proposed, and the BECs in these lattices are simulated and plotted.

  7. Plasmon analysis and homogenization in plane layered photonic crystals and hyperbolic metamaterials

    Science.gov (United States)

    Davidovich, M. V.

    2016-12-01

    Dispersion equations are obtained and analysis and homogenization are carried out in periodic and quasiperiodic plane layered structures consisting of alternating dielectric layers, metal and dielectric layers, as well as graphene sheets and dielectric (SiO2) layers. Situations are considered when these structures acquire the properties of hyperbolic metamaterials (HMMs), i.e., materials the real parts of whose effective permittivity tensor have opposite signs. It is shown that the application of solely dielectric layers is more promising in the context of reducing losses.

  8. Analysis of plasmons and homogenization in a flat-layered photonic crystals and hyperbolic metamaterials

    Science.gov (United States)

    Davidovich, Mikhael V.

    2016-04-01

    The dispersion equation and the analysis and homogenization in periodic and quasiperiodic plane layered structures with alternating dielectric layers of metal and dielectric layers, as well as a graphene sheet and SiO2 layers have been investigated. The cases are considered when these patterns become the properties of hyperbolic metamaterials, i.e., having different signs of the real parts of the tensor components of the effective dielectric constant. It is shown that usage only dielectric layers is perspective in reducing losses.

  9. Prompt gamma-ray activation analysis (PGAA)

    Energy Technology Data Exchange (ETDEWEB)

    Kern, J. [Fribourg Univ. (Switzerland). Inst. de Physique

    1996-11-01

    The paper deals with a brief description of the principles of prompt gamma-ray activation analysis (PGAA), with the detection of gamma-rays, the PGAA project at SINQ and with the expected performances. 8 figs., 3 tabs., 10 refs.

  10. Transforming Teacher Education, An Activity Theory Analysis

    Science.gov (United States)

    McNicholl, Jane; Blake, Allan

    2013-01-01

    This paper explores the work of teacher education in England and Scotland. It seeks to locate this work within conflicting sociocultural views of professional practice and academic work. Drawing on an activity theory framework that integrates the analysis of these seemingly contradictory discourses with a study of teacher educators' practical…

  11. [Development of a membrane inlet-single photon ionization/chemical ionization-mass spectrometer for online analysis of VOCs in water].

    Science.gov (United States)

    Hua, Lei; Wu, Qing-Hao; Hou, Ke-Yong; Cui, Hua-Peng; Chen, Ping; Zhao, Wu-Duo; Xie, Yuan-Yuan; Li, Hai-Yang

    2011-12-01

    A home-made membrane inlet- single photon ionization/chemical ionization- time-of-flight mass spectrometer has been described. A vacuum ultraviolet (VUV) lamp with photon energy of 10.6 eV was used as the light source for single photon ionization (SPI). Chemical ionization (CI) was achieved through ion-molecule reactions with O2- reactant ions generated by photoelectron ionization. The two ionization modes could be rapidly switched by adjusting electric field in the ionization region within 2 s. Membrane inlet system used for rapid enrichment of volatile organic compounds (VOCs) in water was constructed by using a polydimethylsiloxane (PDMS) membrane with a thickness of 50 microm. A purge gas was added to accelerate desorption of analytes from the membrane surface. The purge gas could also help to prevent the pump oil back-streaming into the ionization region from the analyzer chamber and improve the signal to noise ratio (S/N). Achieved detection limits were 2 microg x L(-1) for methyl tert-butyl ether (MTBE) in SPI mode and 1 microg x L(-1) for chloroform in SPI-CI mode within 10 s analysis time, respectively. The instrument has been successfully applied to the rapid analysis of MTBE in simulated underground water nearby petrol station and VOCs in disinfected drinking water. The results indicate that the instrument has a great application prospect for online analysis of VOCs in water.

  12. Online coupling of high-resolution chromatography with extreme UV photon activation tandem mass spectrometry: Application to the structural investigation of complex glycans by dissociative photoionization

    Energy Technology Data Exchange (ETDEWEB)

    Ropartz, David, E-mail: David.Ropartz@nantes.inra.fr [INRA, UR1268 Biopolymers Interactions Assemblies F-44316 Nantes (France); Giuliani, Alexandre [Synchrotron SOLEIL, L' Orme des Merisiers, F-91190 Gif-sur-Yvette (France); UAR 1008 CEPIA, INRA, F-44316 Nantes (France); Fanuel, Mathieu [INRA, UR1268 Biopolymers Interactions Assemblies F-44316 Nantes (France); Hervé, Cécile; Czjzek, Mirjam [Sorbonne Universités, Université Pierre et Marie Curie, Paris VI, CNRS, Integrative Biology of Marine Models, UMR 8227, Station Biologique, Place George Teissier, F29688 Roscoff Cedex (France); Rogniaux, Hélène [INRA, UR1268 Biopolymers Interactions Assemblies F-44316 Nantes (France)

    2016-08-24

    The activation of ions by extreme-energy photons (XUV) produced by a synchrotron radiation beamline is a powerful method for characterizing complex glycans using tandem mass spectrometry (MS). As previously described, this activation method leads to rich fragmentation spectra with many structurally valuable cross-ring cleavages while maintaining labile modifications on the glycan structures. However, until now, the tandem MS event was too long to be compatible with liquid chromatography elution times. In this work, the duty cycle of the activation and detection of fragments was shortened, and the background signal on the spectra was drastically reduced. Both improvements allowed, for the first time, the successful coupling of a UHPLC system to XUV-activated tandem MS. The approach was used to characterize a complex mixture of oligo-porphyrans, which are a class of highly sulfated oligosaccharides, in a fully automated way. Due to an enhanced dynamic range and an increased sensitivity, some hypothetical structures of low abundance have been unequivocally confirmed in this study and others have been revised. Some previously undescribed species of oligo-porphyrans that exhibit lateral branching have been fully resolved. This work contributes to the scarce knowledge of the structure of porphyrans in red algae and pushes the current capacities of XUV-activation tandem MS by demonstrating the possibility of a direct coupling with UHPLC. This study will considerably broaden the applicability and practicality of this method in many fields of analytical biology. - Highlights: • For the first time, XUV photon activation tandem MS was coupled to UHPLC. • The approach was used to characterize a complex mixture of biomolecules. • The MSMS duty cycle was compatible with elution times of UHPLC without compromised. • Minor species were characterized with an enhanced sensitivity and dynamic range. • These results broaden the application of the technique in many field of

  13. Photon-based techniques for nondestructive subsurface analysis of painted cultural heritage artifacts.

    Science.gov (United States)

    Janssens, K; Dik, J; Cotte, M; Susini, J

    2010-06-15

    Often, just micrometers below a painting's surface lies a wealth of information, both with Old Masters such as Peter Paul Rubens and Rembrandt van Rijn and with more recent artists of great renown such as Vincent Van Gogh and James Ensor. Subsurface layers may include underdrawing, underpainting, and alterations, and in a growing number of cases conservators have discovered abandoned compositions on paintings, illustrating artists' practice of reusing a canvas or panel. The standard methods for studying the inner structure of cultural heritage (CH) artifacts are infrared reflectography and X-ray radiography, techniques that are optionally complemented with the microscopic analysis of cross-sectioned samples. These methods have limitations, but recently, a number of fundamentally new approaches for fully imaging the buildup of hidden paint layers and other complex three-dimensional (3D) substructures have been put into practice. In this Account, we discuss these developments and their recent practical application with CH artifacts. We begin with a tabular summary of 14 IR- and X-ray-based imaging methods and then continue with a discussion of each technique, illustrating CH applications with specific case studies. X-ray-based tomographic and laminographic techniques can be used to generate 3D renditions of artifacts of varying dimensions. These methods are proving invaluable for exploring inner structures, identifying the conservation state, and postulating the original manufacturing technology of metallic and other sculptures. In the analysis of paint layers, terahertz time-domain spectroscopy (THz-TDS) can highlight interfaces between layers in a stratigraphic buildup, whereas macrosopic scanning X-ray fluorescence (MA-XRF) has been employed to measure the distribution of pigments within these layers. This combination of innovative methods provides topographic and color information about the micrometer depth scale, allowing us to look "into" paintings in an

  14. Stem cell differentiation indicated by noninvasive photonic characterization and fractal analysis of subcellular architecture.

    Science.gov (United States)

    Chalut, Kevin J; Kulangara, Karina; Wax, Adam; Leong, Kam W

    2011-08-01

    We hypothesised that global structural changes in stem cells would manifest with differentiation, and that these changes would be observable with light scattering microscopy. Analysed with a fractal dimension formalism, we observed significant structural changes in differentiating human mesenchymal stem cells within one day after induction, earlier than could be detected by gene expression profiling. Moreover, light scattering microscopy is entirely non-perturbative, so the same sample could be monitored throughout the differentiation process. We explored one possible mechanism, chromatin remodelling, to account for the changes we observed. Correlating with the staining of HP1α, a heterochromatin protein, we applied novel microscopy methods and fractal analysis to monitor the plastic dynamics of chromatin within stem cell nuclei. We showed that the level of chromatin condensation changed during differentiation, and provide one possible explanation for the changes seen with the light scattering method. These results lend physical insight into stem cell differentiation while providing physics-based methods for non-invasive detection of the differentiation process.

  15. Activity Analysis and Cost Analysis in Medical Schools.

    Science.gov (United States)

    Koehler, John E.; Slighton, Robert L.

    There is no unique answer to the question of what an ongoing program costs in medical schools. The estimates of program costs generated by classical methods of cost accounting are unsatisfactory because such accounting cannot deal with the joint production or joint cost problem. Activity analysis models aim at calculating the impact of alternative…

  16. LightForce Photon-Pressure Collision Avoidance: Updated Efficiency Analysis Utilizing a Highly Parallel Simulation Approach

    Science.gov (United States)

    Stupl, Jan; Faber, Nicolas; Foster, Cyrus; Yang, Fan Yang; Nelson, Bron; Aziz, Jonathan; Nuttall, Andrew; Henze, Chris; Levit, Creon

    2014-01-01

    This paper provides an updated efficiency analysis of the LightForce space debris collision avoidance scheme. LightForce aims to prevent collisions on warning by utilizing photon pressure from ground based, commercial off the shelf lasers. Past research has shown that a few ground-based systems consisting of 10 kilowatt class lasers directed by 1.5 meter telescopes with adaptive optics could lower the expected number of collisions in Low Earth Orbit (LEO) by an order of magnitude. Our simulation approach utilizes the entire Two Line Element (TLE) catalogue in LEO for a given day as initial input. Least-squares fitting of a TLE time series is used for an improved orbit estimate. We then calculate the probability of collision for all LEO objects in the catalogue for a time step of the simulation. The conjunctions that exceed a threshold probability of collision are then engaged by a simulated network of laser ground stations. After those engagements, the perturbed orbits are used to re-assess the probability of collision and evaluate the efficiency of the system. This paper describes new simulations with three updated aspects: 1) By utilizing a highly parallel simulation approach employing hundreds of processors, we have extended our analysis to a much broader dataset. The simulation time is extended to one year. 2) We analyze not only the efficiency of LightForce on conjunctions that naturally occur, but also take into account conjunctions caused by orbit perturbations due to LightForce engagements. 3) We use a new simulation approach that is regularly updating the LightForce engagement strategy, as it would be during actual operations. In this paper we present our simulation approach to parallelize the efficiency analysis, its computational performance and the resulting expected efficiency of the LightForce collision avoidance system. Results indicate that utilizing a network of four LightForce stations with 20 kilowatt lasers, 85% of all conjunctions with a

  17. Single-Photon Technologies Based on Quantum-Dots in Photonic Crystals

    DEFF Research Database (Denmark)

    Lehmann, Tau Bernstorff

    -photon purity under quasi-resonantexcitation. Furthermore the waveguide based platform demonstrates indistinguishable single-photonsat timescales up to 13 ns.A setup for active demultiplexing of single-photons to a three-fold single-photon state is proposed.Using a fast electro-optical modulator, single...

  18. LightForce photon-pressure collision avoidance: Efficiency analysis in the current debris environment and long-term simulation perspective

    Science.gov (United States)

    Yang Yang, Fan; Nelson, Bron; Aziz, Jonathan; Carlino, Roberto; Dono Perez, Andres; Faber, Nicolas; Foster, Cyrus; Frost, Chad; Henze, Chris; Karacalıoğlu, Arif Göktuğ; Levit, Creon; Marshall, William; Mason, James; O'Toole, Conor; Swenson, Jason; Worden, Simon P.; Stupl, Jan

    2016-09-01

    This work provides an efficiency analysis of the LightForce space debris collision avoidance scheme in the current debris environment and describes a simulation approach to assess its impact on the long-term evolution of the space debris environment. LightForce aims to provide just-in-time collision avoidance by utilizing photon pressure from ground-based industrial lasers. These ground stations impart minimal accelerations to increase the miss distance for a predicted conjunction between two objects. In the first part of this paper we will present research that investigates the short-term effect of a few systems consisting of 20 kW class lasers directed by 1.5 m diameter telescopes using adaptive optics. The results found such a network of ground stations to mitigate more than 85 percent of conjunctions and could lower the expected number of collisions in Low Earth Orbit (LEO) by an order of magnitude. While these are impressive numbers that indicate LightForce's utility in the short-term, the remaining 15 % of possible collisions contain (among others) conjunctions between two massive objects that would add large amount of debris if they collide. Still, conjunctions between massive objects and smaller objects can be mitigated. Hence, we choose to expand the capabilities of the simulation software to investigate the overall effect of a network of LightForce stations on the long-term debris evolution. In the second part of this paper, we will present the planned simulation approach for that effort. For the efficiency analysis of collision avoidance in the current debris environment, we utilize a simulation approach that uses the entire Two Line Element (TLE) catalog in LEO for a given day as initial input. These objects are propagated for one year and an all-on-all conjunction analysis is performed. For conjunctions that fall below a range threshold, we calculate the probability of collision and record those values. To assess efficiency, we compare a baseline

  19. Photonic Crystals Physics and Practical Modeling

    CERN Document Server

    Sukhoivanov, Igor A

    2009-01-01

    The great interest in photonic crystals and their applications in the past decade requires a thorough training of students and professionals who can practically apply the knowledge of physics of photonic crystals together with skills of independent calculation of basic characteristics of photonic crystals and modelling of various photonic crystal elements for application in all-optical communication systems. This book combines basic backgrounds in fiber and integrated optics with detailed analysis of mathematical models for 1D, 2D and 3D photonic crystals and microstructured fibers, as well as with descriptions of real algorithms and codes for practical realization of the models.

  20. Nanowire photonics

    Directory of Open Access Journals (Sweden)

    Peter J. Pauzauskie

    2006-10-01

    Full Text Available The development of integrated electronic circuitry ranks among the most disruptive and transformative technologies of the 20th century. Even though integrated circuits are ubiquitous in modern life, both fundamental and technical constraints will eventually test the limits of Moore's law. Nanowire photonic circuitry constructed from myriad one-dimensional building blocks offers numerous opportunities for the development of next-generation optical information processors and spectroscopy. However, several challenges remain before the potential of nanowire building blocks is fully realized. We cover recent advances in nanowire synthesis, characterization, lasing, integration, and the eventual application to relevant technical and scientific questions.

  1. Multiscale statistical analysis of coronal solar activity

    CERN Document Server

    Gamborino, Diana; Martinell, Julio J

    2016-01-01

    Multi-filter images from the solar corona are used to obtain temperature maps which are analyzed using techniques based on proper orthogonal decomposition (POD) in order to extract dynamical and structural information at various scales. Exploring active regions before and after a solar flare and comparing them with quiet regions we show that the multiscale behavior presents distinct statistical properties for each case that can be used to characterize the level of activity in a region. Information about the nature of heat transport is also be extracted from the analysis.

  2. Photon-efficient imaging with a single-photon camera

    Science.gov (United States)

    Shin, Dongeek; Xu, Feihu; Venkatraman, Dheera; Lussana, Rudi; Villa, Federica; Zappa, Franco; Goyal, Vivek K.; Wong, Franco N. C.; Shapiro, Jeffrey H.

    2016-06-01

    Reconstructing a scene's 3D structure and reflectivity accurately with an active imaging system operating in low-light-level conditions has wide-ranging applications, spanning biological imaging to remote sensing. Here we propose and experimentally demonstrate a depth and reflectivity imaging system with a single-photon camera that generates high-quality images from ~1 detected signal photon per pixel. Previous achievements of similar photon efficiency have been with conventional raster-scanning data collection using single-pixel photon counters capable of ~10-ps time tagging. In contrast, our camera's detector array requires highly parallelized time-to-digital conversions with photon time-tagging accuracy limited to ~ns. Thus, we develop an array-specific algorithm that converts coarsely time-binned photon detections to highly accurate scene depth and reflectivity by exploiting both the transverse smoothness and longitudinal sparsity of natural scenes. By overcoming the coarse time resolution of the array, our framework uniquely achieves high photon efficiency in a relatively short acquisition time.

  3. Quantum physical states for describing photonic assisted chemical change: I. Torsional phenomenon at femtosecond time scale

    CERN Document Server

    Tapia, O

    2012-01-01

    Femtosecond torsional relaxation processes experimentally detected and recently reported by Clark et al. (Nature Phys. 8,225 (2012)) are theoretically dissected with a Hilbert/Fock quantum physical (QP) framework incorporating entanglement of photon/matter base states overcoming standard semi-classic vibrational descriptions. The quantum analysis of a generic Z/E (cis/trans) isomerization in abstract QP terms shed light to fundamental roles played by photonic spin and excited electronic singlet coupled to triplet states. It is shown that one photon activation cannot elicit femtosecond phenomenon, while a two-photon pulse would do. Estimated time scales for the two-photon case indicate the process to lie between a slower than electronic Franck-Condon-like transition yet faster than (semi-classic) vibration relaxation ones.

  4. Analysis of accuracy in dose and position in calculations of a treatment planning system for blocked photon fields

    NARCIS (Netherlands)

    vantVeld, AA

    1997-01-01

    Accuracy in dose and position, defined as complementary criteria, was determined for blocked photon field calculations with a pencil beam based treatment planning system. The concept of field accuracy has been defined as a combination of deviations in dose and position. Absolute dose deviations were

  5. Modified Optical Properties of Semiconductor Quantum Dots by Photonic Structures

    Institute of Scientific and Technical Information of China (English)

    XIAO Min

    2004-01-01

    @@ Specially designed photonic structures, such as photonic crystals, can prevent light from propagating in certain directions with specified frequencies.Such photonic stsuctures exhibit many unique features that are highly desirable for the manufacture of photonic integrated circuits.There has been great interest in controlling light-emitters via photonic structures, which can partially suppress and redirect spontaneous emission.Encapsulating an active material in a well-designed photonic structure can successively reduce the active volume.Because the dimensions of the active volume are reduced to a few micrometers, spontaneous emission control can be achieved, which can provide lasing with improved directional, modal control, and reduced noise.

  6. Large-bandwidth planar photonic crystal waveguides

    DEFF Research Database (Denmark)

    Søndergaard, Thomas; Lavrinenko, Andrei

    2002-01-01

    A general design principle is presented for making finite-height photonic crystal waveguides that support leakage-free guidance of light over large frequency intervals. The large bandwidth waveguides are designed by introducing line defects in photonic crystal slabs, where the material in the lin......-free single-mode guidance is found for a large frequency interval covering 60% of the photonic band-gap.......A general design principle is presented for making finite-height photonic crystal waveguides that support leakage-free guidance of light over large frequency intervals. The large bandwidth waveguides are designed by introducing line defects in photonic crystal slabs, where the material in the line...... defect has appropriate dispersion properties relative to the photonic crystal slab material surrounding the line defect. A three-dimensional theoretical analysis is given for large-bandwidth waveguide designs based on a silicon-air photonic crystal slab suspended in air. In one example, the leakage...

  7. Photonic Molecule Lasers Revisited

    Science.gov (United States)

    Gagnon, Denis; Dumont, Joey; Déziel, Jean-Luc; Dubé, Louis J.

    2014-05-01

    Photonic molecules (PMs) formed by coupling two or more optical resonators are ideal candidates for the fabrication of integrated microlasers, photonic molecule lasers. Whereas most calculations on PM lasers have been based on cold-cavity (passive) modes, i.e. quasi-bound states, a recently formulated steady-state ab initio laser theory (SALT) offers the possibility to take into account the spectral properties of the underlying gain transition, its position and linewidth, as well as incorporating an arbitrary pump profile. We will combine two theoretical approaches to characterize the lasing properties of PM lasers: for two-dimensional systems, the generalized Lorenz-Mie theory will obtain the resonant modes of the coupled molecules in an active medium described by SALT. Not only is then the theoretical description more complete, the use of an active medium provides additional parameters to control, engineer and harness the lasing properties of PM lasers for ultra-low threshold and directional single-mode emission. We will extend our recent study and present new results for a number of promising geometries. The authors acknowledge financial support from NSERC (Canada) and the CERC in Photonic Innovations of Y. Messaddeq.

  8. Peltier-Cooled and Actively Quenched Operation of InGaAs/InP Avalanche Photodiodes as Photon Counters at a 1.55-mum Wavelength.

    Science.gov (United States)

    Prochazka, I

    2001-11-20

    The performance of commercially available InGaAs/InP avalanche photodiodes as single-photon detectors at a 1.55-mum wavelength has been investigated. A new active quenching and gating circuit, tailored for operation of these diodes at temperatures in the range from room temperature to -60 degrees C and achievable by means of thermoelectrical cooling, has been developed. Careful tuning of the diodes' operating conditions resulted in a significant reduction of afterpulsing effects; it permitted operation of the detectors with high repetition rates. A noise-equivalent power of 7 x 10(-16) W/Hz(1/2) was obtained at a 1.55-mum wavelength.

  9. Collection and analysis of active particles

    Energy Technology Data Exchange (ETDEWEB)

    DeLong, C.W.

    1950-01-27

    When it became apparent that particles were emanating from the stacks of the separations plants, it become important that the source, size, activity and composition of the particles be determined in order to evaluate the hazard to persons working in and neer the stack areas. The present report will give the results of radiochemical analysis of particles collected by electrostatic precipitation from ``B`` plant canyon ventilation air, not from the off-gas ventilation line. Of importance is the fact the particles analyzed consist not only of particles from the ventilation air but also, unavoidably, of rust from the iron manifold used to conduct the gases to the precipitator. This makes a determination of the activity versus weight ratio impossible, but should not invalidate the radiochemical data.

  10. An novel analog programmable power supply for active gain control of the Multi-Pixel Photon Counter (MPPC)

    CERN Document Server

    Li, Zhengwei; Xu, Yupeng; Yan, Bo; Li, Yanguo; Lu, Xuefeng; Li, Xufang; Zhang, Shuo; Chang, Zhi; Li, Jicheng; Zhang, Yifei; Zhao, Jianling

    2016-01-01

    Silicon Photo-Multipliers (SiPM) are regarded as novel photo-detector to replace conventional Photo-Multiplier Tubes (PMTs). However, the breakdown voltage dependence on the ambient temperature results in a gain variation of $\\sim$3$\\% /^{\\circ} \\mathrm C$. This can severely limit the application of this device in experiments with wide range of operating temperature, especially in space telescope. An experimental setup in dark condition was established to investigate the temperature and bias voltage dependence of gain for the Multi-Pixel Photon Counter (MPPC), one type of the SiPM developed by Hamamatsu. The gain and breakdown voltage dependence on operating temperature of an MPPC can be approximated by a linear function, which is similar to the behavior of a zener diode. The measured temperature coefficient of the breakdown voltage is $(59.4 \\pm 0.4$ mV)$/^{\\circ} \\mathrm C$. According to this fact, a programmable power supply based on two zener diodes and an operational amplifier was designed with a positiv...

  11. Electrically active defects in silica-filled epoxy as revealed by light emission analysis

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, E; Teyssedre, G; Laurent, C [Universite de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, F-31062 Toulouse Cedex 9 (France); Rowe, S; Robiani, S, E-mail: christian.laurent@laplace.univ-tlse.f [Schneider Electric, Direction des Recherches Materiaux, rue Henri Tarze, F-38050 Grenoble (France)

    2009-08-21

    Epoxy resins have long been used as the insulation of electrical systems. They are generally formulated with a dispersion of micro-fillers to improve thermal and mechanical properties. However, there are concerns about the possible influence of these fillers on the electric behaviour, especially on the long term ageing under functional stresses. At the loose interface between matrix and fillers, macro- and micro-voids in the resin can provide weak points that are difficult to detect using conventional spectroscopy. Light emission analysis from the material under electrical stress is an efficient way to reveal such electrically active defects since internal ionizing events would give rise to photon emission. A detailed analysis of the light emitted by silica-filled and unfilled epoxy samples is presented. The photon counting technique, spectral analysis and imaging give a firm basis to discuss the contributing emission processes to the detected signal. They reveal the existence of ionizing events into internal defects. The sensitivity of the optical method is order of magnitudes higher than the sensitivity of conventional partial discharge detection.

  12. Asking Photons Where They Have Been

    Science.gov (United States)

    Danan, A.; Farfurnik, D.; Bar-Ad, S.; Vaidman, L.

    2013-12-01

    We present surprising experimental evidence regarding the past of photons passing through an interferometer. The information about the positions through which the photons pass in the interferometer is retrieved from modulations of the detected signal at the vibration frequencies of mirrors the photons bounce off. From the analysis we conclude that the past of the photons is not represented by continuous trajectories, although a “common sense” analysis adopted in various welcher weg measurements, delayed-choice which-path experiments, and counterfactual communication demonstrations yields a single trajectory. The experimental results have a simple explanation in the framework of the two-state vector formalism of quantum theory.

  13. Mean cell size and collagen orientation from 2D Fourier analysis on confocal laser scanning microscopy and two-photon fluorescence microscopy on human skin in vivo

    Science.gov (United States)

    Lucassen, Gerald W.; Bakker, Bernard L.; Neerken, Sieglinde; Hendriks, Rob F. M.

    2003-07-01

    We present results from 2D Fourier analysis on 3D stacks of images obtained by confocal laser scanning reflectance microscopy (CLSM) and two-photon fluorescence microscopy (2PM) on human skin in vivo. CLSM images were obtained with a modified commercial system (Vivascope1000, Lucid Inc, excitation wavelength 830 nm) equipped with a piezo-focusing element (350 μm range) for depth positioning of the objective lens. 2PM was performed with a specially designed set-up with excitation wavelength 730 nm. Mean cell size in the epidermal layer and structural orientation in the dermal layer have been determined as a function of depth by 2D Fourier analysis. Fourier analysis on microscopic images enables automatic non-invasive quantitative structural analysis (mean cell size and orientation) of living human skin.

  14. Photonic band gap materials

    Science.gov (United States)

    Cassagne, D.

    Photonic band gap materials Photonic band gap materials are periodic dielectric structures that control the propagation of electromagnetic waves. We describe the plane wave method, which allows to calculate the band structures of photonic crystals. By symmetry analysis and a perturbative approach, we predict the appearance of the low energy photonic band gaps of hexagonal structures. We propose new two-dimensional structures called graphite and boron nitride. Using a transfer matrix method, we calculate the transmission of the graphite structure and we show the crucial role of the coupling with external modes. We study the appearance of allowed modes in the photonic band gap by the introduction of localized defects in the periodicity. Finally, we discuss the properties of opals formed by self-organized silica microspheres, which are very promising for the fabrication of three-dimensional photonic crystals. Les matériaux à bandes interdites photoniques sont des structures diélectriques périodiques qui contrôlent la propagation des ondes électromagnétiques. Nous décrivons la méthode des ondes planes qui permet de calculer les structures de bandes des cristaux photoniques. Par une analyse de la symétrie et une approche perturbative, nous précisons les conditions d'existence des bandes interdites de basse énergie. Nous proposons de nouvelles structures bidimensionnelles appelées graphite et nitrure de bore. Grâce à une méthode de matrices de transfert, nous calculons la transmission de la structure graphite et nous mettons en évidence le rôle fondamental du couplage avec les modes extérieurs. Nous étudions l'apparition de modes permis dans la bande interdite grâce à l'introduction de défauts dans la périodicité. Enfin, nous discutons les propriétés des opales constituées de micro-billes de silice auto-organisées, qui sont très prometteuses pour la fabrication de cristaux photoniques tridimensionnels.

  15. Split-step finite-difference time-domain method with perfectly matched layers for efficient analysis of two-dimensional photonic crystals with anisotropic media.

    Science.gov (United States)

    Singh, Gurpreet; Tan, Eng Leong; Chen, Zhi Ning

    2012-02-01

    This Letter presents a split-step (SS) finite-difference time-domain (FDTD) method for the efficient analysis of two-dimensional (2-D) photonic crystals (PhCs) with anisotropic media. The proposed SS FDTD method is formulated with perfectly matched layer boundary conditions and caters for inhomogeneous anisotropic media. Furthermore, the proposed method is derived using the efficient SS1 splitting formulas with simpler right-hand sides that are more efficient and easier to implement. A 2-D PhC cavity with anisotropic media is used as an example to validate the efficiency of the proposed method.

  16. Design of microcavities in diamond-based photonic crystals by Fourier- and real-space analysis of cavity fields

    CERN Document Server

    Riedrich-Möller, Janine; Becher, Christoph

    2010-01-01

    We present the design of two-dimensional photonic crystal microcavities in thin diamond membranes well suited for coupling of color centers in diamond. By comparing simulated and ideal field distributions in Fourier and real space and by according modification of air hole positions and size, we optimize the cavity structure yielding high quality factors up to Q = 320000 with a modal volume of V = 0.35 (lambda/n)^3. Using the very same approach we also improve previous designs of a small modal volume microcavity in silicon, gaining a factor of 3 in cavity Q. In view of practical realization of photonic crystals in synthetic diamond films, it is necessary to investigate the influence of material absorption on the quality factor. We show that this influence can be predicted by a simple model, replacing time consuming simulations.

  17. PHOTON PBL: problem-based learning in photonics technology education

    Science.gov (United States)

    Massa, Nicholas; Audet, Richard; Donnelly, Judith; Hanes, Fenna; Kehrhahn, Marijke

    2007-06-01

    Problem-based learning (PBL) is an educational approach whereby students learn course content by actively and collaboratively solving real-world problems presented in a context similar to that in which the learning is to be applied. Research shows that PBL improves student learning and retention, critical thinking and problem-solving skills, and the ability to skillfully apply knowledge to new situations - skills deemed critical to lifelong learning. Used extensively in medical education since the 1970's, and widely adopted in other fields including business, law, and education, PBL is emerging as an alternative to traditional lecture-based courses in engineering and technology education. In today's ever-changing global economy where photonics technicians are required to work productively in teams to solve complex problems across disciplines as well as cultures, PBL represents an exciting alternative to traditional lecture-based photonics education. In this paper we present the PHOTON PBL project, a National Science Foundation Advanced Technology Education (NSF-ATE) project aimed at creating, in partnership with the photonics industry and university research labs from across the US, a comprehensive series of multimedia-based PBL instructional resource materials and offering faculty professional development in the use of PBL in photonics technology education. Quantitative and qualitative research will be conducted on the effectiveness of PBL in photonics technician education.

  18. [Analysis of single-photon emission computed tomography in patients with hypertensive encephalopathy complicated with previous hypertensive crisis].

    Science.gov (United States)

    Kustkova, H S

    2012-01-01

    In cerebrovascular diseases pefuzionnaya single photon emission computed tomography with lipophilic amines used for the diagnosis of functional disorders of cerebral blood flow. Quantitative calculations helps clarify the nature of vascular disease and clarify the adequacy and effectiveness of the treatment. In this modern program for SPECT ensure conduct not only as to the calculation of blood flow, but also make it possible to compute also the absolute values of cerebral blood flow.

  19. Model-independent analysis of polarization effects in elastic electron-deuteron scattering in presence of two-photon exchange

    Energy Technology Data Exchange (ETDEWEB)

    Gakh, G.I.; Tomasi-Gustafsson, E

    2006-07-01

    The general spin structure of the matrix element, taking into account the 2-photon exchange contribution, for the elastic electron (positron) - deuteron scattering has been derived using general symmetry properties of the hadron electromagnetic interaction, such as P-, C- and T-invariances as well as lepton helicity conservation in QED at high energy. Taking into account also crossing symmetry, the amplitudes of e{sup {+-}}d scattering can be parametrized in terms of fifteen real functions. The expressions for the differential cross section and for all polarization observables are given in terms of these functions. We consider the case of an arbitrary polarized deuteron target and polarized electron beam (both longitudinal and transverse). The transverse polarization of the electron beam induces a single-spin asymmetry which is non-zero in presence of 2-photon exchange. It is shown that elastic deuteron electromagnetic form factors can still be extracted in presence of 2 photon exchange, from the measurements of the differential cross sections and of one polarization observable (for example, the tensor asymmetry) for electron and positron deuteron elastic scattering, in the same kinematical conditions. (authors)

  20. Optomechanical photon shuttling between photonic cavities

    CERN Document Server

    Li, Huan

    2014-01-01

    Mechanical motion of photonic devices driven by optical forces provides a profound means of coupling between optical fields. The current focus of these optomechanical effects has been on cavity optomechanics systems in which co-localized optical and mechanical modes interact strongly to enable wave-mixing between photons and phonons and backaction cooling of mechanical modes. Alternatively, extended mechanical modes can also induce strong nonlocal effects on propagating optical fields or multiple localized optical modes at distances. Here, we demonstrate a novel multi-cavity optomechanical device: a "photon see-saw", in which torsional optomechanical motion can shuttle photons between two photonic crystal nanocavities. The resonance frequencies of the two cavities, one on each side of the see-saw, are modulated anti-symmetrically by the device's rotation. Pumping photons into one cavity excites optomechanical self-oscillation which strongly modulates the inter-cavity coupling and shuttles photons to the other...

  1. Optomechanical photon shuttling between photonic cavities.

    Science.gov (United States)

    Li, Huan; Li, Mo

    2014-11-01

    Mechanical motion of photonic devices driven by optical forces provides a profound means of coupling between optical fields. The current focus of these optomechanical effects has been on cavity optomechanics systems in which co-localized optical and mechanical modes interact strongly to enable wave mixing between photons and phonons, and backaction cooling of mechanical modes. Alternatively, extended mechanical modes can also induce strong non-local effects on propagating optical fields or multiple localized optical modes at distances. Here, we demonstrate a multicavity optomechanical device in which torsional optomechanical motion can shuttle photons between two photonic crystal nanocavities. The resonance frequencies of the two cavities, one on each side of this 'photon see-saw', are modulated antisymmetrically by the device's rotation. Pumping photons into one cavity excites optomechanical self-oscillation, which strongly modulates the inter-cavity coupling and shuttles photons to the other empty cavity during every oscillation cycle in a well-regulated fashion.

  2. Harmonic distortion in microwave photonic filters.

    Science.gov (United States)

    Rius, Manuel; Mora, José; Bolea, Mario; Capmany, José

    2012-04-09

    We present a theoretical and experimental analysis of nonlinear microwave photonic filters. Far from the conventional condition of low modulation index commonly used to neglect high-order terms, we have analyzed the harmonic distortion involved in microwave photonic structures with periodic and non-periodic frequency responses. We show that it is possible to design microwave photonic filters with reduced harmonic distortion and high linearity even under large signal operation.

  3. The condensation of the corona for the correlation between the hard X-ray photon index Γ and the reflection scaling factor ℜ in active galactic nuclei

    Science.gov (United States)

    Qiao, Erlin; Liu, B. F.

    2017-01-01

    Observationally, it is found that there is a strong correlation between the hard X-ray photon index Γ and the Compton reflection scaling factor ℜ in active galactic nuclei. In this paper, we propose that the Γ - ℜ correlation can be explained within the framework of the condensation of the hot corona onto the cold accretion disc around a supermassive black hole. In the model, it is presumed that, initially, a vertically extended hot gas (corona) is supplied to the central supermassive black hole by capturing the interstellar medium and stellar wind. In this scenario, when the initial mass accretion rate dot{M}/ dot{M}_Edd gtrsim 0.01, at a critical radius rd, part of the hot gas begins to condense onto the equatorial disc plane of the black hole, forming an inner cold accretion disc. Then the matter is accreted in the form of the disc-corona structure extending down to the innermost stable circular orbits of the black hole. The size of the inner disc is determined by the initial mass accretion rate. With the increase of the initial mass accretion rate, the size of the inner disc increases, which results in both the increase of the Compton reflection scaling factor ℜ and the increase of the hard X-ray photon index Γ. By comparing with a sample of Seyfert galaxies with well-fitted X-ray spectra, it is found that our model can roughly explain the observations. Finally, we discuss the possibility to apply our model to high mass X-ray binaries, which are believed to be fueled by the hot wind from the companion star.

  4. Photon-Photon Collisions -- Past and Future

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, Stanley J.; /SLAC

    2005-12-02

    I give a brief review of the history of photon-photon physics and a survey of its potential at future electron-positron colliders. Exclusive hadron production processes in photon-photon and electron-photon collisions provide important tests of QCD at the amplitude level, particularly as measures of hadron distribution amplitudes. There are also important high energy {gamma}{gamma} and e{gamma} tests of quantum chromodynamics, including the production of jets in photon-photon collisions, deeply virtual Compton scattering on a photon target, and leading-twist single-spin asymmetries for a photon polarized normal to a production plane. Since photons couple directly to all fundamental fields carrying the electromagnetic current including leptons, quarks, W's and supersymmetric particles, high energy {gamma}{gamma} collisions will provide a comprehensive laboratory for Higgs production and exploring virtually every aspect of the Standard Model and its extensions. High energy back-scattered laser beams will thus greatly extend the range of physics of the International Linear Collider.

  5. Mitigating Photon Jitter in Optical PPM Communication

    Science.gov (United States)

    Moision, Bruce

    2008-01-01

    A theoretical analysis of photon-arrival jitter in an optical pulse-position-modulation (PPM) communication channel has been performed, and now constitutes the basis of a methodology for designing receivers to compensate so that errors attributable to photon-arrival jitter would be minimized or nearly minimized. Photon-arrival jitter is an uncertainty in the estimated time of arrival of a photon relative to the boundaries of a PPM time slot. Photon-arrival jitter is attributable to two main causes: (1) receiver synchronization error [error in the receiver operation of partitioning time into PPM slots] and (2) random delay between the time of arrival of a photon at a detector and the generation, by the detector circuitry, of a pulse in response to the photon. For channels with sufficiently long time slots, photon-arrival jitter is negligible. However, as durations of PPM time slots are reduced in efforts to increase throughputs of optical PPM communication channels, photon-arrival jitter becomes a significant source of error, leading to significant degradation of performance if not taken into account in design. For the purpose of the analysis, a receiver was assumed to operate in a photon- starved regime, in which photon counts follow a Poisson distribution. The analysis included derivation of exact equations for symbol likelihoods in the presence of photon-arrival jitter. These equations describe what is well known in the art as a matched filter for a channel containing Gaussian noise. These equations would yield an optimum receiver if they could be implemented in practice. Because the exact equations may be too complex to implement in practice, approximations that would yield suboptimal receivers were also derived.

  6. Content Analysis in Systems Engineering Acquisition Activities

    Science.gov (United States)

    2016-04-30

    qÜáêíÉÉåíÜ=^ååì~ä= ^Åèìáëáíáçå=oÉëÉ~êÅÜ= póãéçëáìã= tÉÇåÉëÇ~ó=pÉëëáçåë= sçäìãÉ=f= = Content Analysis in Systems Engineering Acquisition Activities Karen...Ü~åÖÉ= - 47 - Panel 3. Systems Engineering : New Thinking for a New Age Wednesday, May 4, 2016 11:15 a.m. – 12:45 p.m. Chair: John D. Burrow...Deputy Assistant Secretary of the Navy for Research, Development, Test, & Evaluation (DASN RDT&E) Rethinking the Systems Engineering Process in Light

  7. Analysis of physical activities in Taekwondo Pumsae.

    Science.gov (United States)

    Lee, Sang-Bock; Cha, Eun-Jong; Lee, Tae-Soo

    2008-01-01

    Exercise is very important element for successful aging. Among many sports events, Korea is the suzerain of Taekwondo. When competing (Taekwondo Free Fighting) after learning Poomse as basic movements and inuring them, people compete with movements depending on situation. Among Poomses of Taekwondo, Taegeuk Poomse consists of very basic movements from 1 Jang to 8 Jang and they are for inuring to body. In order to prescribe Taegeuk Jang, which is the basic movement of Taekwondo that Korea is the suzerain, as an exercise for successful aging, it is necessary to analyze physical activity level of each Taegeuk Jang (From 1 Jang through 8 Jang) and suggest the same. Therefore, in this study, I analyzed physical activity level of each Jang of Taegeuk Poomse by attaching Armband made by Body Media Company on brachia and legs below knee of Taekwondo trainees. The result of the analysis of the whole momentum from Taegeuk 1 Jang to 8 Jang is as follows: First, the average absolute value of acceleration variation of vertical direction signal (L-MAD): 5.15. Second, the average absolute value of acceleration variation of horizontal direction signal (T-MAD): 3.44. Finally, the average of calorie consumption per minute (AEE/Min): 5.06 Cal. The obtained result corresponds to proper exercise condition for successful aging and it can be utilized as data for exercise prescription for the young and the old.

  8. Hybrid Integrated Platforms for Silicon Photonics

    Directory of Open Access Journals (Sweden)

    John E. Bowers

    2010-03-01

    Full Text Available A review of recent progress in hybrid integrated platforms for silicon photonics is presented. Integration of III-V semiconductors onto silicon-on-insulator substrates based on two different bonding techniques is compared, one comprising only inorganic materials, the other technique using an organic bonding agent. Issues such as bonding process and mechanism, bonding strength, uniformity, wafer surface requirement, and stress distribution are studied in detail. The application in silicon photonics to realize high-performance active and passive photonic devices on low-cost silicon wafers is discussed. Hybrid integration is believed to be a promising technology in a variety of applications of silicon photonics.

  9. Photonic crystal slab quantum well infrared photodetector

    Science.gov (United States)

    Kalchmair, S.; Detz, H.; Cole, G. D.; Andrews, A. M.; Klang, P.; Nobile, M.; Gansch, R.; Ostermaier, C.; Schrenk, W.; Strasser, G.

    2011-01-01

    In this letter we present a quantum well infrared photodetector (QWIP), which is fabricated as a photonic crystal slab (PCS). With the PCS it is possible to enhance the absorption efficiency by increasing photon lifetime in the detector active region. To understand the optical properties of the device we simulate the PCS photonic band structure, which differs significantly from a real two-dimensional photonic crystal. By fabricating a PCS-QWIP with 100x less quantum well doping, compared to a standard QWIP, we are able to see strong absorption enhancement and sharp resonance peaks up to temperatures of 170 K.

  10. Silicon photonics III systems and applications

    CERN Document Server

    Lockwood, David

    2016-01-01

    This book is volume III of a series of books on silicon photonics. It reports on the development of fully integrated systems where many different photonics component are integrated together to build complex circuits. This is the demonstration of the fully potentiality of silicon photonics. It contains a number of chapters written by engineers and scientists of the main companies, research centers and universities active in the field. It can be of use for all those persons interested to know the potentialities and the recent applications of silicon photonics both in microelectronics, telecommunication and consumer electronics market.

  11. Portal Connecting Dark Photons and Axions

    Science.gov (United States)

    Kaneta, Kunio; Lee, Hye-Sung; Yun, Seokhoon

    2017-03-01

    The dark photon and the axion (or axionlike particle) are popular light particles of the hidden sector. Each of them has been actively searched for through the couplings called the vector portal and the axion portal. We introduce a new portal connecting the dark photon and the axion (axion-photon-dark photon, axion-dark photon-dark photon), which emerges in the presence of the two particles. This dark axion portal is genuinely new couplings, not just from a product of the vector portal and the axion portal, because of the internal structure of these couplings. We present a simple model that realizes the dark axion portal and discuss why it warrants a rich phenomenology.

  12. Parameter analysis of a photonic crystal fiber with raised-core index profile based on effective index method

    Institute of Scientific and Technical Information of China (English)

    Faramarz E. Seraji; Mahnaz Rashidi; Vajieh Khasheie

    2006-01-01

    @@ Photonic crystal fibers (PCFs) with a stepped raised-core profile and one layer equally spaced holes in the cladding are analyzed. Using effective index method and considering a raised step refractive index difference between the index of the core and the effective index of the cladding, we improve the characteristic parameters such as numerical aperture and V-parameter, and reduce its bending loss to about one tenth of a conventional PCF. Implementing such a structure in PCFs may be one step forward to achieve low loss PCFs for communication applications.

  13. Transmission Near-Infrared (NIR) and Photon Time-of-Flight (PTOF) Spectroscopy in a Comparative Analysis of Pharmaceuticals

    DEFF Research Database (Denmark)

    Kamran, Faisal; Abildgaard, Otto Højager Attermann; Sparén, Anders

    2015-01-01

    near-infrared spectroscopy (NIRS). In contrast to transmission NIRS, PTOFS is capable of directly and independently determining the absorption and reduced scattering coefficients of the medium. Chemometric models were built on the evaluated absorption spectra for predicting tablet drug concentration......We present a comprehensive study of the application of photon time-of-flight spectroscopy (PTOFS) in the wavelength range 1050– 1350 nm as a spectroscopic technique for the evaluation of the chemical composition and structural properties of pharmaceutical tablets. PTOFS is compared to transmission...

  14. Numerical analysis of Raman amplification and optical signal-to-noise ratio in a photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    Tao Shang; Jianping Chen; Xinwan Li; Junhe Zhou

    2006-01-01

    @@ A numerical design on the triangular photonic crystal fiber (PCF) based backward multi-pump Raman amplifier is presented. It is demonstrated that high flat Raman gain can be reached based on PCF.Influences of different geometric parameters and germanium doping concentrations on the Raman net gain, amplified spontaneous emission (ASE) noise and double Rayleigh backscattering (DRBS) of the signal have been analyzed. For optimizing crystal fiber Raman amplifier (FRA), there is tradeoff between the geometric parameter and germanium doping concentration of triangular PCF. The results show that PCF is an appropriate candidate for high gain Raman amplifiers.

  15. Detection of infrared photons with a superconductor

    Institute of Scientific and Technical Information of China (English)

    ZHANG LaBao; ZHONG YangYin; KANG Lin; CHEN Jian; JI ZhengMing; XU WeiWei; CAO ChunHai

    2009-01-01

    A superconductor single photon detector based on NbN nanowire was fabricated using electron beam lithography (EBL) and reactive ion etching (RIE) for infrared photon detection. When biased well below its critical current at 4.2 K, NbN nanowire is very sensitive to the incident photons. Typical telecommunication photons with a wavelength of 1550 nm were detected by this detector. Data analysis indicates the repeating rate of the device with 200 nm NbN nanowire may be up to 100 MHz, and the quantum efficiency is about 0.01% when biased at 0.95Ic.

  16. Proposed Inclusive Dark Photon Search at LHCb.

    Science.gov (United States)

    Ilten, Philip; Soreq, Yotam; Thaler, Jesse; Williams, Mike; Xue, Wei

    2016-06-24

    We propose an inclusive search for dark photons A^{'} at the LHCb experiment based on both prompt and displaced dimuon resonances. Because the couplings of the dark photon are inherited from the photon via kinetic mixing, the dark photon A^{'}→μ^{+}μ^{-} rate can be directly inferred from the off-shell photon γ^{*}→μ^{+}μ^{-} rate, making this a fully data-driven search. For run 3 of the LHC, we estimate that LHCb will have sensitivity to large regions of the unexplored dark-photon parameter space, especially in the 210-520 MeV and 10-40 GeV mass ranges. This search leverages the excellent invariant-mass and vertex resolution of LHCb, along with its unique particle-identification and real-time data-analysis capabilities.

  17. Inclusive Dark Photon Search at LHCb

    CERN Document Server

    Ilten, Philip; Thaler, Jesse; Williams, Mike; Xue, Wei

    2016-01-01

    We propose an inclusive search for dark photons $A'$ at the LHCb experiment based on both prompt and displaced di-muon resonances. Because the couplings of the dark photon are inherited from the photon via kinetic mixing, the dark photon $A' \\to \\mu^+ \\mu^-$ rate can be directly inferred from the off-shell photon $\\gamma^* \\to \\mu^+ \\mu^-$ rate, making this a fully data-driven search. For Run 3 of the LHC, we estimate that LHCb will have sensitivity to large regions of the unexplored dark-photon parameter space, especially in the 210-520 MeV and 10-40 GeV mass ranges. This search leverages the excellent invariant-mass and vertex resolution of LHCb, along with its unique particle-identification and real-time data-analysis capabilities.

  18. Photonic Crystals Towards Nanoscale Photonic Devices

    CERN Document Server

    Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexis

    2005-01-01

    Just like the periodical crystalline potential in solid-state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as a cage for storing, filtering or guiding light at the wavelength scale thus paves the way to the realisation of optical and optoelectronic devices with ultimate properties and dimensions. This should contribute toward meeting the demands for a greater miniaturisation that the processing of an ever increasing number of data requires. Photonic Crystals intends at providing students and researchers from different fields with the theoretical background needed for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, from optics to microwaves, where photonic crystals have found applications. As such, it aims at building brid...

  19. Photonic Crystals Towards Nanoscale Photonic Devices

    CERN Document Server

    Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexei; Pagnoux, Dominique

    2008-01-01

    Just like the periodical crystalline potential in solid state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as cages for storing, filtering or guiding light at the wavelength scale paves the way to the realization of optical and optoelectronic devices with ultimate properties and dimensions. This will contribute towards meeting the demands for greater miniaturization imposed by the processing of an ever increasing number of data. Photonic Crystals will provide students and researchers from different fields with the theoretical background required for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, ranging from optics to microwaves, where photonic crystals have found application. As such, it aims at building bridges between...

  20. Nuclear photonics

    Science.gov (United States)

    Habs, D.; Günther, M. M.; Jentschel, M.; Thirolf, P. G.

    2012-07-01

    With the planned new γ-beam facilities like MEGa-ray at LLNL (USA) or ELI-NP at Bucharest (Romania) with 1013 γ/s and a band width of ΔEγ/Eγ≈10-3, a new era of γ beams with energies up to 20MeV comes into operation, compared to the present world-leading HIγS facility at Duke University (USA) with 108 γ/s and ΔEγ/Eγ≈3ṡ10-2. In the long run even a seeded quantum FEL for γ beams may become possible, with much higher brilliance and spectral flux. At the same time new exciting possibilities open up for focused γ beams. Here we describe a new experiment at the γ beam of the ILL reactor (Grenoble, France), where we observed for the first time that the index of refraction for γ beams is determined by virtual pair creation. Using a combination of refractive and reflective optics, efficient monochromators for γ beams are being developed. Thus, we have to optimize the total system: the γ-beam facility, the γ-beam optics and γ detectors. We can trade γ intensity for band width, going down to ΔEγ/Eγ≈10-6 and address individual nuclear levels. The term "nuclear photonics" stresses the importance of nuclear applications. We can address with γ-beams individual nuclear isotopes and not just elements like with X-ray beams. Compared to X rays, γ beams can penetrate much deeper into big samples like radioactive waste barrels, motors or batteries. We can perform tomography and microscopy studies by focusing down to μm resolution using Nuclear Resonance Fluorescence (NRF) for detection with eV resolution and high spatial resolution at the same time. We discuss the dominating M1 and E1 excitations like the scissors mode, two-phonon quadrupole octupole excitations, pygmy dipole excitations or giant dipole excitations under the new facet of applications. We find many new applications in biomedicine, green energy, radioactive waste management or homeland security. Also more brilliant secondary beams of neutrons and positrons can be produced.

  1. Photon-photon scattering: a tutorial

    CERN Document Server

    Liang, Yi

    2011-01-01

    Long-established results for the low-energy photon-photon scattering, gamma gamma --> gamma gamma, have recently been questioned. We analyze that claim and demonstrate that it is inconsistent with experience. We demonstrate that the mistake originates from an erroneous manipulation of divergent integrals and discuss the connection with another recent claim about the Higgs decay into two photons. We show a simple way of correctly computing the low-energy gamma gamma scattering.

  2. Azimuthal correlations in photon-photon collisions

    CERN Document Server

    Artéaga-Romero, N; Kessler, P; Ong, S; Panella, O

    1995-01-01

    Using the general helicity formula for \\gamma^* \\gamma^* collisions, we are showing that it should be possible to determine a number of independent ``structure functions'', i.e. linear combinations of elements of the two-photon helicity tensor, through azimuthal correlations in two-body or quasi two-body reactions induced by the photon-photon interaction, provided certain experimental conditions are satisfied. Numerical results of our computations are presented for some particular processes and dynamic models.

  3. Dispersion properties of photonic crystal fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Dridi, Kim;

    1998-01-01

    Approximate dispersion and bending properties of all-silica two-dimensional photonic crystal fibres are characterised by the combination of an effective-index model and classical analysis tools for optical fibres. We believe for the first time to have predicted the dispersion properties of photonic...... crystal fibres. The results strongly indicate that these fibres have potential applications as dispersion managing components...

  4. Analysis of the temperature dependence of the spectral characteristics for the hollow-core photonic-crystal fibers

    Science.gov (United States)

    Bzheumikhov, K. A.; Margushev, Z. Ch.; Savoiskii, Yu. V.

    2013-07-01

    The temperature dependence of the spectral characteristics of monocapillaries made of S87-2 glass and filled with air and ethanol is experimentally and theoretically studied in temperature intervals 23-90°C and 23-40°C, respectively. The same measurements are performed using the photonic-crystal fibers made of AR-Glass (Schott). The transmission spectra of the air-filled fibers are slightly transformed when the temperature is varied in the above interval. It is demonstrated that the transmission peak is red-shifted and the shift is proportional to the temperature when the cavities are filled with ethanol. It is also demonstrated that the temperature dependence of the shape of the transmission spectra is predominantly determined by the parameters of the medium that fills the hollow channel rather than the fiber material. The temperature sensitivities of the photonic-crystal fiber filled with ethanol and a monocapillary are 1.25 and 0.40 nm/°C, respectively.

  5. Operating cost analysis of anaesthesia: Activity based costing (ABC analysis

    Directory of Open Access Journals (Sweden)

    Majstorović Branislava M.

    2011-01-01

    Full Text Available Introduction. Cost of anaesthesiology represent defined measures to determine a precise profile of expenditure estimation of surgical treatment, which is important regarding planning of healthcare activities, prices and budget. Objective. In order to determine the actual value of anaestesiological services, we started with the analysis of activity based costing (ABC analysis. Methods. Retrospectively, in 2005 and 2006, we estimated the direct costs of anestesiological services (salaries, drugs, supplying materials and other: analyses and equipment. of the Institute of Anaesthesia and Resuscitation of the Clinical Centre of Serbia. The group included all anesthetized patients of both sexes and all ages. We compared direct costs with direct expenditure, “each cost object (service or unit” of the Republican Health-care Insurance. The Summary data of the Departments of Anaesthesia documented in the database of the Clinical Centre of Serbia. Numerical data were utilized and the numerical data were estimated and analyzed by computer programs Microsoft Office Excel 2003 and SPSS for Windows. We compared using the linear model of direct costs and unit costs of anaesthesiological services from the Costs List of the Republican Health-care Insurance. Results. Direct costs showed 40% of costs were spent on salaries, (32% on drugs and supplies, and 28% on other costs, such as analyses and equipment. The correlation of the direct costs of anaestesiological services showed a linear correlation with the unit costs of the Republican Healthcare Insurance. Conclusion. During surgery, costs of anaesthesia would increase by 10% the surgical treatment cost of patients. Regarding the actual costs of drugs and supplies, we do not see any possibility of costs reduction. Fixed elements of direct costs provide the possibility of rationalization of resources in anaesthesia.

  6. The efficacy of photon-initiated photoacoustic streaming and sonic-activated irrigation combined with QMiX solution or sodium hypochlorite against intracanal E. faecalis biofilm.

    Science.gov (United States)

    Balić, M; Lucić, R; Mehadžić, K; Bago, I; Anić, I; Jakovljević, S; Plečko, V

    2016-02-01

    The aim of the study was to assess the antibacterial efficacy of photon-initiated photoacoustic streaming (PIPS) using an Er:YAG laser and sonic-activated irrigation combined with QMiX irrigant or sodium hypochlorite against Enterococcus faecalis intracanal biofilm. Root canals of 91 human extracted single-canal teeth were instrumented, sterilized, contaminated with E. faecalis and incubated for 15 days. The infected teeth were then randomly distributed into six experimental groups: G1: PIPS/Er:YAG laser (wavelength 2940 nm, pulse energy 20 mJ, 15 Hz, pulse duration 50 μs, energy density 2.06 J/cm(2), 3 × 20 s) with the QMiX irrigant; G2: PIPS/Er:YAG laser-activated 2.5 % NaOCl; G3 sonic-activated irrigation (EndoActivator system) for 60 s with the QMiX irrigant; G4 sonic-activated irrigation for 60 s with 2.5 % NaOCl; G5 30-gauge needle irrigation with the QMiX irrigant; G6 30-gauge needle irrigation with 2.5 % NaOCl. The positive control group was rinsed with sterile saline solution. The root canals were sampled by flushing with saline solution at baseline and after the treatments, serially diluted and cultured. The number of bacteria in each canal was determined by plate count. The presence and the absence of E. faecalis in root canals were demonstrated by polymerase chain reaction (PCR), and the pattern of the bacteria colonization was visualized by scanning electron microscopy. There was significant reduction in the bacterial population for all groups (p < 0.001). The best antibacterial efficacy was recorded after sonic-activated irrigation with both NaOCl (99.999 %) and QMiX (99.999 %) and after PIPS with QMiX (99.999 %), which were more effective than conventional irrigation with NaOCl (99.998 %) and the PIPS with the NaOCl (99.966 %). Also, the PIPS with QMiX solution provided the highest number of sterile samples (five). There was no difference in the bacteria reduction between the active irrigation techniques, regardless of the irrigant used

  7. High precision photon flux determination for photon tagging experiments

    Science.gov (United States)

    Teymurazyan, A.; Ahmidouch, A.; Ambrozewicz, P.; Asratyan, A.; Baker, K.; Benton, L.; Burkert, V.; Clinton, E.; Cole, P.; Collins, P.; Dale, D.; Danagoulian, S.; Davidenko, G.; Demirchyan, R.; Deur, A.; Dolgolenko, A.; Dzyubenko, G.; Ent, R.; Evdokimov, A.; Feng, J.; Gabrielyan, M.; Gan, L.; Gasparian, A.; Glamazdin, A.; Goryachev, V.; Hardy, K.; He, J.; Ito, M.; Jiang, L.; Kashy, D.; Khandaker, M.; Kolarkar, A.; Konchatnyi, M.; Korchin, A.; Korsch, W.; Kosinov, O.; Kowalski, S.; Kubantsev, M.; Kubarovsky, V.; Larin, I.; Lawrence, D.; Li, X.; Martel, P.; Matveev, V.; McNulty, D.; Mecking, B.; Milbrath, B.; Minehart, R.; Miskimen, R.; Mochalov, V.; Nakagawa, I.; Overby, S.; Pasyuk, E.; Payen, M.; Pedroni, R.; Prok, Y.; Ritchie, B.; Salgado, C.; Shahinyan, A.; Sitnikov, A.; Sober, D.; Stepanyan, S.; Stevens, W.; Underwood, J.; Vasiliev, A.; Vishnyakov, V.; Wood, M.; Zhou, S.

    2014-12-01

    The Jefferson Laboratory PrimEx Collaboration has developed and implemented a method to control the tagged photon flux in photoproduction experiments at the 1% level over the photon energy range from 4.9 to 5.5 GeV. This method has been successfully implemented in a high precision measurement of the neutral pion lifetime. Here, we outline the experimental equipment and the analysis techniques used to accomplish this. These include the use of a total absorption counter for absolute flux calibration, a pair spectrometer for online relative flux monitoring, and a new method for post-bremsstrahlung electron counting.

  8. [Real-time analysis of polyvinyl chloride thermal decomposition/combustion products with single photon ionization/photoelectron ionization online mass spectrometer].

    Science.gov (United States)

    Chen, Wen-Dong; Hou, Ke-Yong; Chen, Ping; Li, Fang-Long; Zhao, Wu-Duo; Cui, Hua-Peng; Hua, Lei; Xie, Yuan-Yuan; Li, Hai-Yang

    2013-01-01

    With the features of a broad range of ionizable compounds, reduced fragments and simple mass spectrum, a homemade magnetic field enhanced photoelectron ionization (MEPEI) source combined with single photon ionization (SPI) for time-of-flight mass spectrometer was built and applied to analyze thermal decomposition/combustion products of polyvinyl chloride (PVC). The combined ion source can be switched very fast between SPI mode and SPI-MEPEI mode for detecting different targeted compounds, and only adjusting the voltage of the electrode in the ionization region to trigger the switch. Among the PVC thermal decomposition/combustion products, HCl and CO2, which ionization energies (12.74 eV, 13.77 eV respectively) were higher than the energy of photon (10.60 eV), were ionized by MEPEI, while alkenes, dichloroethylene, benzene and its homologs, monochlorobenzene, styrene, indane, naphthalene and its homologs were ionized by SPI and MEPEI simultaneously. Spectra of interested products as a function of temperatures indicated that products are formed via two main mechanisms: (1) dechlorination and intramolecular cyclization can lead to the formation of HCl, benzene and naphthalene at 250-370 degrees C; (2) intermolecular crosslinking leads to the formation of alkyl aromatics such as toluene and xylene/ethylbenzene at 380-510 degrees C. The experimental results show that the combined ion source of SPI/ SPI-MEPEI for TOF-MS has broad application prospects in the online analysis field.

  9. All photons are equal but some photons are more equal than others

    CERN Document Server

    Töppel, Falk; Leuchs, Gerd

    2011-01-01

    Photons indistinguishability is studied from a pragmatic, rather than speculative, point of view. As consequence of a detailed analysis of the coincidence probability distribution in a Hong-Ou- Mandel experiment, we introduce the concept of rate of distinguishability of photons. For photons prepared in a given, but arbitrary, state, this parameter allows one to make a quantitative analysis of their indistinguishability. Among other things, our study reveals that coupling between different degrees of freedom of the electromagnetic field, plays a crucial role in photons indistinguishability.

  10. Progress in neutron activation analysis for uranium

    Institute of Scientific and Technical Information of China (English)

    杜鸿善; 李贵群; 董桂芝; 李俊兰; K.H.Chiu; C.M.Wai

    1996-01-01

    A new type of extractant, sym-dibenzo-16-crown-5-oxyhydroxamic acid (HL) is introduced. The extractions of UO22+, Na+, K+, Sr2+, Ba2+ and Br- were studied with HL in chloroform. The results obtained show that UO22+ can be quantitatively extracted at pH values above 5, whereas the extractions of K+, Na+, Sr2+, Ba2+ and Br- are negligible in the pH range of 2 - 7. The dependence of the distribution ratio of U(VI) on both the concentration of the HL and pH are linear, and they have the same slope of 2. This suggests that U(VI) appears to form a 1:2 complex with ligand. Uranium(VI) can be selectively separated and concentrated from interfering elements such as Na, K, Sr and Br by solvent extraction with HL under specific conditions. The recovery of uranium is nearly 100% and the radionudear purity of uranium is greater than 99.99%. Therefore, neutron activation analysis has greatly improved the sensitivity and accuracy for the detection of trace uranium from seawater.

  11. {sup 124}Sb - Activity measurement and determination of photon emission intensities; {sup 124}Sb - Mesure de l'activite et determination des intensites photoniques

    Energy Technology Data Exchange (ETDEWEB)

    Be, M.M.; Chauvenet, B.

    2009-07-15

    The international traceability of antimony 124, in term of activity, is very limited. The results of {sup 124}Sb activity measurements sent to the SIR (BIPM - International System of Reference, BIPM.RI(II)-K1.Sb-124.) are scarce. Up to now, only three laboratories have contributed. Two of them carried out measurements using the 4pibeta-gamma coincidence counting technique and the third one using the 4pigamma method with a well-type crystal detector. The first two results are in agreement but the last one differs significantly from them, by 2 %. The decay scheme consistency cannot be excluded when trying to explain those discrepancies. In other respects, this nuclide emits high-energy gamma rays, and then could be selected as a valuable standard radionuclide for the calibration of gamma-ray detectors in that energy range, given well known photon intensities. Those considerations led to the proposal of an international exercise and to the realisation of this Euromet project, registered as project no. 907, coordinated by CEA-List-LNE/LNHB. The first part of this exercise was dedicated to activity measurements and to their comparison. For this purpose, participants were asked to make use of all the direct measurement techniques available in their laboratory in order to confirm or not the existence of possible biases specific to some measuring methods. In addition, this exercise offered the opportunity of improving the uncertainties of the gamma-ray intensities. Then, participants were asked, in the second part of the exercise, to carry out X-ray and gamma-ray intensity measurements. These results have been compared to previous published values and new decay scheme data are proposed. Eight international laboratories participated in this exercise. (authors)

  12. A custom image-based analysis tool for quantifying elastin and collagen micro-architecture in the wall of the human aorta from multi-photon microscopy.

    Science.gov (United States)

    Koch, Ryan G; Tsamis, Alkiviadis; D'Amore, Antonio; Wagner, William R; Watkins, Simon C; Gleason, Thomas G; Vorp, David A

    2014-03-21

    The aorta possesses a micro-architecture that imparts and supports a high degree of compliance and mechanical strength. Alteration of the quantity and/or arrangement of the main load-bearing components of this micro-architecture--the elastin and collagen fibers--leads to mechanical, and hence functional, changes associated with aortic disease and aging. Therefore, in the future, the ability to rigorously characterize the wall fiber micro-architecture could provide insight into the complicated mechanisms of aortic wall remodeling in aging and disease. Elastin and collagen fibers can be observed using state-of-the-art multi-photon microscopy. Image-analysis algorithms have been effective at characterizing fibrous constructs using various microscopy modalities. The objective of this study was to develop a custom MATLAB-language automated image-based analysis tool to describe multiple parameters of elastin and collagen micro-architecture in human soft fibrous tissue samples using multi-photon microscopy images. Human aortic tissue samples were used to develop the code. The tool smooths, cleans and equalizes fiber intensities in the image before segmenting the fibers into a binary image. The binary image is cleaned and thinned to a fiber skeleton representation of the image. The developed software analyzes the fiber skeleton to obtain intersections, fiber orientation, concentration, porosity, diameter distribution, segment length and tortuosity. In the future, the developed custom image-based analysis tool can be used to describe the micro-architecture of aortic wall samples in a variety of conditions. While this work targeted the aorta, the software has the potential to describe the architecture of other fibrous materials, tube-like networks and connective tissues.

  13. Theoretical analysis and modeling of a photonic integrated circuit for frequency 8-tupled and 24-tupled millimeter wave signal generation.

    Science.gov (United States)

    Hasan, Mehedi; Guemri, Rabiaa; Maldonado-Basilio, Ramón; Lucarz, Frédéric; de Bougrenet de la Tocnaye, Jean-Louis; Hall, Trevor

    2014-12-15

    A photonic circuit design for implementing frequency 8-tupling and 24-tupling is proposed. The front- and back-end of the circuit comprises 4×4 MMI couplers enclosing an array of four pairs of phase modulators and 2×2 MMI couplers. The proposed design for frequency multiplication requires no optical or electrical filters, the operation is not limited to carefully adjusted modulation indexes, and the drift originated from static DC bias is mitigated by making use of the intrinsic phase relations of multi-mode interference couplers. A transfer matrix approach is used to represent the main building blocks of the design and hence to describe the operation of the frequency 8-tupling and 24-tupling. The concept is theoretically developed and demonstrated by simulations. Ideal and imperfect power imbalances in the multi-mode interference couplers, as well as ideal and imperfect phases of the electric drives to the phase modulators, are analyzed.

  14. Analysis of ultra-high sensitivity configuration in chip-integrated photonic crystal microcavity bio-sensors

    Energy Technology Data Exchange (ETDEWEB)

    Chakravarty, Swapnajit, E-mail: swapnajit.chakravarty@omegaoptics.com; Hosseini, Amir; Xu, Xiaochuan [Omega Optics, Inc., Austin, Texas 78757 (United States); Zhu, Liang; Zou, Yi [Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, Texas 78758 (United States); Chen, Ray T., E-mail: raychen@uts.cc.utexas.edu [Omega Optics, Inc., Austin, Texas 78757 (United States); Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, Texas 78758 (United States)

    2014-05-12

    We analyze the contributions of quality factor, fill fraction, and group index of chip-integrated resonance microcavity devices, to the detection limit for bulk chemical sensing and the minimum detectable biomolecule concentration in biosensing. We analyze the contributions from analyte absorbance, as well as from temperature and spectral noise. Slow light in two-dimensional photonic crystals provide opportunities for significant reduction of the detection limit below 1 × 10{sup −7} RIU (refractive index unit) which can enable highly sensitive sensors in diverse application areas. We demonstrate experimentally detected concentration of 1 fM (67 fg/ml) for the binding between biotin and avidin, the lowest reported till date.

  15. Numerical analysis of a photonic crystal fiber based on a surface plasmon resonance sensor with an annular analyte channel

    Science.gov (United States)

    Liu, Chao; Yang, Lin; Su, Weiquan; Wang, Famei; Sun, Tao; Liu, Qiang; Mu, Haiwei; Chu, Paul K.

    2017-01-01

    A sensing structure is designed with a photonic crystal fiber based on a surface plasmon resonance (PCF-SPR) sensor using gold as the sensitive material. The benefit of the structure is to reduce the difficulty in gold deposition, because the Au film is deposited on the outside of the fiber core instead of on the holes filled with analyte inside the core. The properties of the sensor are numerically calculated by the finite element method. The results show that the thickness of the gold film, refractive index of the analyte, and radius of the central hole affect the sensing performance of the PCF-SPR. By optimizing the model, an extra graphene layer with the thickness of 20 nm is deposited on the gold film in the model. The maximum spectral sensitivity can be as high as 7500 nm/RIU for the sensor with the gold-graphene composite film as the sensitive material.

  16. High energy photon-photon collisions

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Zerwas, P.M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    1994-07-01

    The collisions of high energy photons produced at a electron-positron collider provide a comprehensive laboratory for testing QCD, electroweak interactions and extensions of the standard model. The luminosity and energy of the colliding photons produced by back-scattering laser beams is expected to be comparable to that of the primary e{sup +}e{sup {minus}} collisions. In this overview, we shall focus on tests of electroweak theory in photon-photon annihilation, particularly {gamma}{gamma} {yields} W{sup +}W{sup {minus}}, {gamma}{gamma} {yields} Higgs bosons, and higher-order loop processes, such as {gamma}{gamma} {yields} {gamma}{gamma}, Z{gamma} and ZZ. Since each photon can be resolved into a W{sup +}W{sup minus} pair, high energy photon-photon collisions can also provide a remarkably background-free laboratory for studying WW collisions and annihilation. We also review high energy {gamma}{gamma} tests of quantum chromodynamics, such as the scaling of the photon structure function, t{bar t} production, mini-jet processes, and diffractive reactions.

  17. Experimental analysis of general ion recombination in a liquid-filled ionization chamber in high-energy photon beams

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Eunah; Seuntjens, Jan [Medical Physics Unit, McGill University, Montreal General Hospital (L5-113), 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada); Davis, Stephen [Department of Medical Physics, McGill University Health Centre, Montreal General Hospital (L5-112), 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada)

    2013-06-15

    Purpose: To study experimentally the general ion recombination effect in a liquid-filled ionization chamber (LIC) in high-energy photon beams. Methods: The general ion recombination effect on the response of a micro liquid ion chamber (microLion) was investigated with a 6 MV photon beam in normal and SRS modes produced from a Varian{sup Registered-Sign} Novalis Tx{sup TM} linear accelerator. Dose rates of the linear accelerator were set to 100, 400, and 1000 MU/min, which correspond to pulse repetition frequencies of 60, 240, and 600 Hz, respectively. Polarization voltages applied to the microLion were +800 and +400 V. The relative collection efficiency of the microLion response as a function of dose per pulse was experimentally measured with changing polarization voltage and pulse repetition frequencies and was compared with the theoretically calculated value. Results: For the 60 Hz pulse repetition frequency, the experimental relative collection efficiency was not different from the theoretical one for a pulsed beam more than 0.3% for both polarization voltages. For a pulsed radiation beam with a higher pulse repetition frequency, the experimental relative collection efficiency converged to the theoretically calculated efficiency for continuous beams. This result indicates that the response of the microLion tends toward the response to a continuous beam with increasing pulse repetition frequency of a pulsed beam because of low ion mobility in the liquid. Conclusions: This work suggests an empirical method to correct for differences in general ion recombination of a LIC between different radiation fields. More work is needed to quantitatively explain the LIC general ion recombination behavior in pulsed beams generated from linear accelerators.

  18. Photonic Design for Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Kosten, E.; Callahan, D.; Horowitz, K.; Pala, R.; Atwater, H.

    2014-08-28

    We describe photonic design approaches for silicon photovoltaics including i) trapezoidal broadband light trapping structures ii) broadband light trapping with photonic crystal superlattices iii) III-V/Si nanowire arrays designed for broadband light trapping.

  19. Composite Photon Theory Versus Elementary Photon Theory

    CERN Document Server

    Perkins, Walton A

    2015-01-01

    The purpose of this paper is to show that the composite photon theory measures up well against the Standard Model's elementary photon theory. This is done by comparing the two theories area by area. Although the predictions of quantum electrodynamics are in excellent agreement with experiment (as in the anomalous magnetic moment of the electron), there are some problems, such as the difficulty in describing the electromagnetic field with the four-component vector potential because the photon has only two polarization states. In most areas the two theories give similar results, so it is impossible to rule out the composite photon theory. Pryce's arguments in 1938 against a composite photon theory are shown to be invalid or irrelevant. Recently, it has been realized that in the composite theory the antiphoton does not interact with matter because it is formed of a neutrino and an antineutrino with the wrong helicity. This leads to experimental tests that can determine which theory is correct.

  20. Optical properties of photonic crystals

    CERN Document Server

    Sakoda, Kazuaki

    2001-01-01

    The interaction between the radiation field and matter is the most fundamen­ tal source of dynamics in nature. It brings about the absorption and emission of photons, elastic and inelastic light scattering, the radiative lifetime of elec­ tronic excited states, and so on. The huge amount of energy carried from the sun by photons is the source of all activities of creatures on the earth. The absorption of photons by chlorophylls and the successive electronic excita­ tion initiate a series of chemical reactions that are known as photosynthesis, which support all life on the earth. Radiative energy is also the main source of all meteorological phenomena. The fundamentals of the radiation field and its interaction with matter were clarified by classical electromagnetism and quantum electrodynamics. These theories, we believe, explain all electromagnetic phenomena. They not only provide a firm basis for contemporary physics but also generate a vast range of technological applications. These include television, ...

  1. Speckle statistics of entangled photons

    CERN Document Server

    Klein, Avraham; Spivak, Boris

    2016-01-01

    We consider the propagation of several entangled photons through an elastically scattering medium and study statistical properties of their speckle patterns. We find the spatial correlations of multiphoton speckles and their sensitivity to changes of system parameters. Our analysis covers both the directed-wave regime, where rays propagate almost ballistically while experiencing small-angle diffusion, and the real-space diffusive regime. We demonstrate that long-range correlations of the speckle patterns dominate experimental signatures for large-aperture photon detectors. We also show that speckle sensitivity depends strongly on the number of photons $N$ in the incoming beam, increasing as $\\sqrt{N}$ in the directed-wave regime and as $N$ in the diffusive regime.

  2. Prompt photon production and photon-hadron jet correlations with POWHEG

    CERN Document Server

    Jezo, T; König, F

    2016-01-01

    We present a calculation of direct photon production at next-to-leading order of QCD and a matching of this calculation with parton showers using POWHEG BOX. Based on simulations with POWHEG+PYTHIA, we perform a detailed phenomenological analysis of PHENIX data on prompt photon production and photon-hadron jet correlations in pp collisions at RHIC, considerably improving the description of these data with respect to previous calculations, and we suggest additional interesting analyses.

  3. OCCAMS: Optically Controlled and Corrected Active Meta-material Space Structures (Ultra-Lightweight Photonic Muscle Space Structures Phase II) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Photons weigh nothing. Why must even small space telescopes have high mass? Our team has demonstrated this is not the case using a completely novel approach to...

  4. Relativistic evaluation of the two-photon decay of the metastable ${1s}^{2} 2s 2p~^3\\mbox{P}_0$ state in berylliumlike ions with an active-electron model

    CERN Document Server

    Amaro, Pedro; Safari, Laleh; Machado, Jorge; Guerra, Mauro; Indelicato, Paul; Santos, José Paulo

    2015-01-01

    The two-photon ${1s}^{2} 2s 2p~^3\\mbox{P}_0 \\rightarrow {1s}^{2} {2s}^2$ $^1\\mbox{S}_0$ transition in berylliumlike ions is theoretically investigated within a full relativistic framework and a second-order perturbation theory. We focus our analysis on how electron correlation, as well as the negative-energy spectrum can affect the forbidden $E1M1$ decay rate. For this purpose we include the electronic correlation by an effective potential and within an active-electron model. Due to its experimental interest, evaluation of decay rates are performed for berylliumlike xenon and uranium. We find that the negative-energy contribution can be neglected in the present decay rate. On the other hand, if contributions of electronic correlation are not carefully taken into account, it may change the lifetime of the metastable state by 20\\%. By performing a full-relativistic $jj$-coupling calculation, we found discrepancies for the decay rate of an order of 2 compared to non-relativistic $LS$-coupling calculations, for t...

  5. Photonic crystal fibers

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Hansen, K P; Nielsen, M D;

    2003-01-01

    Photonic crystal fibers having a complex microstructure in the transverse plane constitute a new and promising class of optical fibers. Such fibers can either guide light through total internal reflection or the photonic bandgap effect, In this paper, we review the different types and applications...... of photonic crystal fibers with particular emphasis on recent advances in the field....

  6. Diffusion Based Photon Mapping

    DEFF Research Database (Denmark)

    Schjøth, Lars; Olsen, Ole Fogh; Sporring, Jon

    2006-01-01

    . To address this problem we introduce a novel photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way we preserve the important illumination features......, while eliminating noise. We call our method diffusion based photon mapping....

  7. Diffusion Based Photon Mapping

    DEFF Research Database (Denmark)

    Schjøth, Lars; Fogh Olsen, Ole; Sporring, Jon

    2007-01-01

    . To address this problem we introduce a novel photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way we preserve the important illumination features......, while eliminating noise. We call our method diffusion based photon mapping....

  8. State transition analysis of spontaneous branch migration of the Holliday junction by photon-based single-molecule fluorescence resonance energy transfer.

    Science.gov (United States)

    Okamoto, Kenji; Sako, Yasushi

    2016-02-01

    Branch migration of Holliday junction (HJ) DNA in solution is a spontaneous conformational change between multiple discrete states. We applied single-molecule fluorescence resonance energy transfer (smFRET) measurement to three-state branch migration. The photon-based variational Bayes-hidden Markov model (VB-HMM) method was applied to fluorescence signals to reproduce the state transition trajectories and evaluate the transition parameters, such as transition rate. The upper limit of time resolution suggested in simulation was nearly achieved for the state dynamics with relatively small FRET changes, and the distinctions in the populations of different states were successfully retrieved. We also discuss the suitability of the HJ as a standard sample for smFRET dynamics measurements and data analysis.

  9. Analysis of the $\\pi^+ \\pi^- \\pi^+ \\pi-$ and $\\pi^+ \\pi^{0}\\pi^- \\pi^{0}$ final states in quasi-real two-photon collisions at LEP

    CERN Document Server

    Achard, P; Aguilar-Benítez, M; Alcaraz, J; Alemanni, G; Allaby, J; Aloisio, A; Alviggi, M G; Anderhub, H; Andreev, V P; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Bajo, A; Baksay, G; Baksay, L; Baldew, S V; Banerjee, S; Banerjee, Sw; Barczyk, A; Barillère, R; Bartalini, P; Basile, M; Batalova, N; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Bellucci, L; Berbeco, R; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Biasini, M; Biglietti, M; Biland, A; Blaising, J J; Blyth, S C; Bobbink, G J; Böhm, A; Boldizsar, L; Borgia, B; Bottai, S; Bourilkov, D; Bourquin, M; Braccini, S; Branson, J G; Brochu, F; Burger, J D; Burger, W J; Cai, X D; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A; Casaus, J; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada, M; Chamizo-Llatas, M; Chang, Y H; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chiefari, G; Cifarelli, L; Cindolo, F; Clare, I; Clare, R; Coignet, G; Colino, N; Costantini, S; de la Cruz, B; Cucciarelli, S; De Asmundis, R; Deglon, P; Debreczeni, J; Degré, A; Dehmelt, K; Deiters, K; Della Volpe, D; Delmeire, E; Denes, P; De Notaristefani, F; De Salvo, A; Diemoz, M; Dierckxsens, M; Dionisi, C; Dittmar, M; Doria, A; Dova, M T; Duchesneau, D; Duda, M; Echenard, B; Eline, A; El-Hage, A; El-Mamouni, H; Engler, A; Eppling, F J; Extermann, P; Falagán, M A; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, M; Ferguson, T; Fesefeldt, H; Fiandrini, E; Field, J H; Filthaut, F; Fisher, P H; Fisher, W; Forconi, G; Freudenreich, K; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gataullin, M; Gentile, S; Giagu, S; Gong, Z F; Grenier, G; Grimm, O; Grünewald, M W; Guida, M; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hirschfelder, J; Hofer, H; Hohlmann, M; Holzner, G; Hou, S R; Jin, B N; Jindal, P; Jones, L W; de Jong, P; Josa-Mutuberria, I; Kaur, M; Kienzle-Focacci, M N; Kim, J K; Kirkby, J; Kittel, W; Klimentov, A; König, A C; Kopal, M; Koutsenko, V; Kraber, M; Krämer, R W; Krüger, A; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Le Goff, J M; Leiste, R; Levtchenko, M; Levchenko, P; Li, C; Likhoded, S; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lü, Y S; Luci, C; Luminari, L; Lustermann, W; Ma, W G; Malgeri, L; Malinin, A; Maña, C; Mans, J; Martin, J P; Marzano, F; Mazumdar, K; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Mihul, A; Milcent, H; Mirabelli, G; Mnich, J; Mohanty, G B; Muanza, G S; Muijs, A J M; Musy, M; Nagy, S; Natale, S; Napolitano, M; Nessi-Tedaldi, F; Nesterov, S; Newman, H; Nisati, A; Novák, T; Nowak, H; Ofierzynski, R; Organtini, G; Pal, I; Palomares, C; Paolucci, P; Paramatti, R; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, F; Pedace, M; Pensotti, S; Perret-Gallix, D; Piccolo, D; Pierella, F; Pieri, M; Pioppi, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Pothier, J; Prokofev, D; Rahal-Callot, G; Rahaman, M A; Raics, P; Raja, N; Ramelli, R; Rancoita, P G; Ranieri, R; Raspereza, A; Razis, P; Rembeczki, S; Ren, D; Rescigno, M; Reucroft, S; Riemann, S; Riles, K; Roe, B P; Romero, L; Rosca, A; Rosemann, C; Rosenbleck, C; Rosier-Lees, S; Roth, S; Rubio, J A; Ruggiero, G; Rykaczewski, H; Sakharov, A; Saremi, S; Sarkar, S; Salicio, J; Sánchez, E; Schäfer, C; Schopper, H; Schotanus, D J; Sciacca, C; Servoli, L; Shevchenko, S; Shivarov, N; Shumilov, V Shoutko E; Shvorob, A; Son, D; Souga, C; Spillantini, P; Steuer, M; Stickland, D P; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Sushkov, S; Swain, H Suter J D; Szillási, Z; Tang, X W; Tarjan, P; Tauscher, L; Taylor, L; Tellili, B; Teyssier, D; Timmermans, C; Samuel; Ting, C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tung, K L; Ulbricht, J; Valente, E; Van de Walle, R T; Vásquez, R; Vesztergombi, G; Vetlitskii, I; Viertel, G; Vivargent, M; Vlachos, S; Vodopyanov, I; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Wadhwa, M; Wang, Q; Wang, X L; Wang, Z M; Weber, M; Wynhoff, S; Xia, L; Xu, Z Z; Yamamoto, J; Yang, B Z; Yang, C G; Yang, H J; Yang, M; Yeh, S C; Zalite, A; Zalite, Yu; Zhang, Z P; Zhao, J; Zhu, G Y; Zhu, R Y; Zhuang, H L; Zichichi, A; Zimmermann, B; Zöller, M

    2006-01-01

    The reactions gamma gamma -> pi^+pi^-pi^+pi^- and gamma gamma -> pi^+pi^0pi^-pi^0 are studied with the L3 detector at LEP in a data sample collected at centre-of-mass energies from 161GeV to 209GeV with a total integrated luminosity of 698/pb. A spin-parity-helicity analysis of the rho^0 rho^0 and rho^+ rho^- systems for two-photon centre-of-mass energies between 1GeV and 3GeV shows the dominance of the spin-parity state 2+ with helicity 2. The contribution of 0+ and 0- spin-parity states is also observed, whereas contributions of 2- states and of a state with spin-parity 2+ and zero helicity are found to be negligible.

  10. Ultrafast photonic crystal optical switching

    Institute of Scientific and Technical Information of China (English)

    GONG Qi-huang; HU Xiao-yong

    2006-01-01

    Photonic crystal,a novel and artificial photonic material with periodic dielectric distribution,possesses photonic bandgap and can control the propagation states of photons.Photonic crystal has been considered to be a promising candidate for the future integrated photonic devices.The properties and the fabrication method of photonic crystal are expounded.The progresses of the study of ultrafast photonic crystal optical switching are discussed in detail.

  11. The negligible photodesorption of methanol ice and the active photon-induced desorption of its irradiation products

    CERN Document Server

    Cruz-Diaz, Gustavo A; Caro, Guillermo M Muñoz; Chen, Y -J

    2016-01-01

    Methanol is a common component of interstellar and circumstellar ice mantles and is often used as an evolution indicator in star-forming regions. The observations of gas-phase methanol in the interiors of dense molecular clouds at temperatures as low as 10 K suggests that a non-thermal ice desorption must be active. Ice photodesorption was proposed to explain the abundances of gas-phase molecules toward the coldest regions. Laboratory experiments were performed to investigate the potential photodesorption of methanol toward the coldest regions. Solid methanol was deposited at 8 K and UV-irradiated at various temperatures starting from 8 K. The irradiation of the ice was monitored by means of infrared spectroscopy and the molecules in the gas phase were detected using quadrupole mass spectroscopy. Fully deuterated methanol was used for confirmation of the results. The photodesorption of methanol to the gas phase was not observed in the mass spectra at different irradiation temperatures. We estimate an upper li...

  12. Induced arousal following zolpidem treatment in a vegetative state after brain injury in 7 cases Analysis using visual single photon emission computerized tomography and digitized cerebral state monitor

    Institute of Scientific and Technical Information of China (English)

    Bo Du; Aijun Shan; Di Yang; Wei Xiang

    2008-01-01

    BACKGROUND: Several studies have reported the use of zolpidem for induced arousal after permanent vegetative states. However, changes in brain function and EMG after zolpidem treatment requires further investigation. OBJECTIVE: To investigate the effect of zolpidem, an unconventional drug, on inducing arousal in patients in a permanent vegetative state after brain injury using visual single photon emission computerized tomography and digitized cerebral state monitor. DESIGN: A self-controlled observation. SETTING: Shenzhen People's Hospital.PARTICIPANTS: Seven patients in a permanent vegetative state were selected from the Department of Neurosurgery, Shenzhen People's Hospital from March 2005 to May 2007. The group included 5 males and 2 females, 24–55 years of age, with a mean age of 38.5 years. All seven patients had been in a permanent vegetative statement for at least six months. The patient group included three comatose patients, who had sustained injuries to the cerebral cortex, basal ganglia, or thalamus in motor vehicle accidents, and four patients, who had suffered primary/secondary brain stem injury. Informed consents were obtained from the patients’ relatives. METHODS: The patients brains were imaged by 99Tcm ECD single photon emission computerized tomography prior to treatment with zolpidem [Sanofi Winthrop Industrie, France, code number approved by the State Food & Drug Administration (SFDA) J20040033, specification 10 mg per tablet. At 8:00 p.m., 10 mg zolpidem was dissolved with distilled water and administered through a nasogastric tube at 1 hour before and after treatment and 1 week following treatment, respectively. Visual analysis of cerebral perfusion changes in the injured brain regions before and after treatment was performed. Simultaneously, three monitoring parameters were obtained though a cerebral state monitor, which included cerebral state index, electromyographic index, and burst suppression index. MAIN OUTCOME MEASURES: Comparison

  13. Silicon photonics manufacturing.

    Science.gov (United States)

    Zortman, William A; Trotter, Douglas C; Watts, Michael R

    2010-11-08

    Most demonstrations in silicon photonics are done with single devices that are targeted for use in future systems. One of the costs of operating multiple devices concurrently on a chip in a system application is the power needed to properly space resonant device frequencies on a system's frequency grid. We asses this power requirement by quantifying the source and impact of process induced resonant frequency variation for microdisk resonators across individual die, entire wafers and wafer lots for separate process runs. Additionally we introduce a new technique, utilizing the Transverse Electric (TE) and Transverse Magnetic (TM) modes in microdisks, to extract thickness and width variations across wafers and dice. Through our analysis we find that a standard six inch Silicon on Insulator (SOI) 0.35 μm process controls microdisk resonant frequencies for the TE fundamental resonances to within 1 THz across a wafer and 105 GHz within a single die. Based on demonstrated thermal tuner technology, a stable manufacturing process exhibiting this level of variation can limit the resonance trimming power per resonant device to 231 μW. Taken in conjunction with the power to compensate for thermal environmental variations, the expected power requirement to compensate for fabrication-induced non-uniformities is 17% of that total. This leads to the prediction that thermal tuning efficiency is likely to have the most dominant impact on the overall power budget of silicon photonics resonator technology.

  14. Solar Hidden Photon Search

    CERN Document Server

    Schwarz, Matthias; Redondo, Javier; Ringwald, Andreas; Wiedemann, Guenter

    2011-01-01

    The Solar Hidden Photon Search (SHIPS) is a joint astroparticle project of the Hamburger Sternwarte and DESY. The main target is to detect the solar emission of a new species of particles, so called Hidden Photons (HPs). Due to kinetic mixing, photons and HPs can convert into each other as they propagate. A small number of solar HPs - originating from photon to HP oscillations in the interior of the Sun - can be converted into photons in a long vacuum pipe pointing to the Sun - the SHIPS helioscope.

  15. Solar Hidden Photon Search

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Matthias; Wiedemann, Guenter [Hamburg Univ. (Germany). Sternwarte; Lindner, Axel; Ringwald, Andreas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Redondo, Javier [Max-Planck-Institut fuer Physik und Astrophysik, Muenchen (Germany)

    2011-11-15

    The Solar Hidden Photon Search (SHIPS) is a joint astroparticle project of the Hamburger Sternwarte and DESY. The main target is to detect the solar emission of a new species of particles, so called Hidden Photons (HPs). Due to kinetic mixing, photons and HPs can convert into each other as they propagate. A small number of solar HPs - originating from photon to HP oscillations in the interior of the Sun - can be converted into photons in a long vacuum pipe pointing to the Sun - the SHIPS helioscope. (orig.)

  16. Intruder Activity Analysis under Unreliable Sensor Networks

    Energy Technology Data Exchange (ETDEWEB)

    Tae-Sic Yoo; Humberto E. Garcia

    2007-09-01

    This paper addresses the problem of counting intruder activities within a monitored domain by a sensor network. The deployed sensors are unreliable. We characterize imperfect sensors with misdetection and false-alarm probabilities. We model intruder activities with Markov Chains. A set of Hidden Markov Models (HMM) models the imperfect sensors and intruder activities to be monitored. A novel sequential change detection/isolation algorithm is developed to detect and isolate a change from an HMM representing no intruder activity to another HMM representing some intruder activities. Procedures for estimating the entry time and the trace of intruder activities are developed. A domain monitoring example is given to illustrate the presented concepts and computational procedures.

  17. Aspherical photon and anti-photon surfaces

    Directory of Open Access Journals (Sweden)

    G.W. Gibbons

    2016-12-01

    Full Text Available In this note we identify photon surfaces and anti-photon surfaces in some physically interesting spacetimes, which are not spherically symmetric. All of our examples solve physically reasonable field equations, including for some cases the vacuum Einstein equations, albeit they are not asymptotically flat. Our examples include the vacuum C-metric, the Melvin solution of Einstein–Maxwell theory and generalisations including dilaton fields. The (anti-photon surfaces are not round spheres, and the lapse function is not always constant.

  18. Photonic crystal fibers: fundamentals to emerging applications

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard

    2005-01-01

    A review of the fundamental properties of photonic crystal fibers is presented. Special focus is held on the emerging fields of application within areas such as actively controlled fiber devices and high-power fiber lasers.......A review of the fundamental properties of photonic crystal fibers is presented. Special focus is held on the emerging fields of application within areas such as actively controlled fiber devices and high-power fiber lasers....

  19. High-Throughput Analysis of Enzyme Activities

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Guoxin [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    High-throughput screening (HTS) techniques have been applied to many research fields nowadays. Robot microarray printing technique and automation microtiter handling technique allows HTS performing in both heterogeneous and homogeneous formats, with minimal sample required for each assay element. In this dissertation, new HTS techniques for enzyme activity analysis were developed. First, patterns of immobilized enzyme on nylon screen were detected by multiplexed capillary system. The imaging resolution is limited by the outer diameter of the capillaries. In order to get finer images, capillaries with smaller outer diameters can be used to form the imaging probe. Application of capillary electrophoresis allows separation of the product from the substrate in the reaction mixture, so that the product doesn't have to have different optical properties with the substrate. UV absorption detection allows almost universal detection for organic molecules. Thus, no modifications of either the substrate or the product molecules are necessary. This technique has the potential to be used in screening of local distribution variations of specific bio-molecules in a tissue or in screening of multiple immobilized catalysts. Another high-throughput screening technique is developed by directly monitoring the light intensity of the immobilized-catalyst surface using a scientific charge-coupled device (CCD). Briefly, the surface of enzyme microarray is focused onto a scientific CCD using an objective lens. By carefully choosing the detection wavelength, generation of product on an enzyme spot can be seen by the CCD. Analyzing the light intensity change over time on an enzyme spot can give information of reaction rate. The same microarray can be used for many times. Thus, high-throughput kinetic studies of hundreds of catalytic reactions are made possible. At last, we studied the fluorescence emission spectra of ADP and obtained the detection limits for ADP under three different

  20. Neutron activation analysis of wheat samples

    Energy Technology Data Exchange (ETDEWEB)

    Galinha, C. [CERENA-IST, Technical University of Lisbon, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Instituto Tecnoclogico e Nuclear, URSN, E.N. 10, 2686-953 Sacavem (Portugal); Anawar, H.M. [Instituto Tecnoclogico e Nuclear, URSN, E.N. 10, 2686-953 Sacavem (Portugal); Freitas, M.C., E-mail: cfreitas@itn.pt [Instituto Tecnoclogico e Nuclear, URSN, E.N. 10, 2686-953 Sacavem (Portugal); Pacheco, A.M.G. [CERENA-IST, Technical University of Lisbon, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Almeida-Silva, M. [Instituto Tecnoclogico e Nuclear, URSN, E.N. 10, 2686-953 Sacavem (Portugal); Coutinho, J.; Macas, B.; Almeida, A.S. [INRB/INIA-Elvas, National Institute of Biological Resources, Est. Gil Vaz, 7350-228 Elvas (Portugal)

    2011-11-15

    The deficiency of essential micronutrients and excess of toxic metals in cereals, an important food items for human nutrition, can cause public health risk. Therefore, before their consumption and adoption of soil supplementation, concentrations of essential micronutrients and metals in cereals should be monitored. This study collected soil and two varieties of wheat samples-Triticum aestivum L. (Jordao/bread wheat), and Triticum durum L. (Marialva/durum wheat) from Elvas area, Portugal and analyzed concentrations of As, Cr, Co, Fe, K, Na, Rb and Zn using Instrumental Neutron Activation Analysis (INAA) to focus on the risk of adverse public health issues. The low variability and moderate concentrations of metals in soils indicated a lower significant effect of environmental input on metal concentrations in agricultural soils. The Cr and Fe concentrations in soils that ranged from 93-117 and 26,400-31,300 mg/kg, respectively, were relatively high, but Zn concentration was very low (below detection limit <22 mg/kg) indicating that soils should be supplemented with Zn during cultivation. The concentrations of metals in roots and straw of both varieties of wheat decreased in the order of K>Fe>Na>Zn>Cr>Rb>As>Co. Concentrations of As, Co and Cr in root, straw and spike of both varieties were higher than the permissible limits with exception of a few samples. The concentrations of Zn in root, straw and spike were relatively low (4-30 mg/kg) indicating the deficiency of an essential micronutrient Zn in wheat cultivated in Portugal. The elemental transfer from soil to plant decreases with increasing growth of the plant. The concentrations of various metals in different parts of wheat followed the order: Root>Straw>Spike. A few root, straw and spike samples showed enrichment of metals, but the majority of the samples showed no enrichment. Potassium is enriched in all samples of root, straw and spike for both varieties of wheat. Relatively to the seed used for cultivation

  1. Slow-light enhanced correlated photon pair generation in a silicon photonic crystal waveguide.

    Science.gov (United States)

    Xiong, C; Monat, Christelle; Clark, Alex S; Grillet, Christian; Marshall, Graham D; Steel, M J; Li, Juntao; O'Faolain, Liam; Krauss, Thomas F; Rarity, John G; Eggleton, Benjamin J

    2011-09-01

    We report the generation of correlated photon pairs in the telecom C-band at room temperature from a dispersion-engineered silicon photonic crystal waveguide. The spontaneous four-wave mixing process producing the photon pairs is enhanced by slow-light propagation enabling an active device length of less than 100 μm. With a coincidence to accidental ratio of 12.8 at a pair generation rate of 0.006 per pulse, this ultracompact photon pair source paves the way toward scalable quantum information processing realized on-chip.

  2. Folded cladding porous shaped photonic crystal fiber with high sensitivity in optical sensing applications: Design and analysis

    Directory of Open Access Journals (Sweden)

    Bikash Kumar Paul

    2017-02-01

    Full Text Available A micro structure folded cladding porous shaped with circular air hole photonic crystal fiber (FP-PCF is proposed and numerically investigated in a broader wavelength range from 1.4 µm to 1.64 µm (E+S+C+L+U for chemical sensing purposes. Employing finite element method (FEM with anisotropic perfectly matched layer (PML various properties of the proposed FP-PCF are numerically inquired. Filling the hole of core with aqueous analyte ethanol (n = 1.354 and tuning different geometric parameters of the fiber, the sensitivity order of 64.19% and the confinement loss of 2.07 × 10-5 dB/m are attained at 1.48 µm wavelength in S band. The investigated numerical simulation result strongly focuses on sensing purposes; because this fiber attained higher sensitivity with lower confinement loss over the operating wavelength. Measuring time of sensitivity, simultaneously confinement loss also inquired. It reflects that confinement loss is highly dependable on PML depth but not for sensitivity. Beside above properties numerical aperture (NA, nonlinearity, and effective area are also computed. This FP-PCF also performed as sensor for other alcohol series (methanol, propanol, butanol, pentanol. Optimized FP-PCF shows higher sensitivity and low confinement loss carrying high impact in the area of chemical as well as gas sensing purposes. Surely it is clear that install such type of sensor will flourish technology massively.

  3. Analysis of a random modulation single photon counting differential absorption lidar system for space-borne atmospheric CO2 sensing.

    Science.gov (United States)

    Ai, X; Pérez-Serrano, A; Quatrevalet, M; Nock, R W; Dahnoun, N; Ehret, G; Esquivias, I; Rarity, J G

    2016-09-05

    The ability to observe the Earth's carbon cycles from space provides scientists an important tool to analyze climate change. Current proposed systems are mainly based on pulsed integrated path differential absorption lidar, in which two high energy pulses at different wavelengths interrogate the atmosphere sequentially for its transmission properties and are back-scattered by the ground. In this work an alternative approach based on random modulation single photon counting is proposed and analyzed; this system can take advantage of a less power demanding semiconductor laser in intensity modulated continuous wave operation, benefiting from a better efficiency, reliability and radiation hardness. Our approach is validated via numerical simulations considering current technological readiness, demonstrating its potential to obtain a 1.5 ppm retrieval precision for 50 km averaging with 2.5 W average power in a space-borne scenario. A major limiting factor is the ambient shot noise, if ultra-narrow band filtering technology could be applied, 0.5 ppm retrieval precision would be attainable.

  4. Denoising two-photon calcium imaging data.

    Science.gov (United States)

    Malik, Wasim Q; Schummers, James; Sur, Mriganka; Brown, Emery N

    2011-01-01

    Two-photon calcium imaging is now an important tool for in vivo imaging of biological systems. By enabling neuronal population imaging with subcellular resolution, this modality offers an approach for gaining a fundamental understanding of brain anatomy and physiology. Proper analysis of calcium imaging data requires denoising, that is separating the signal from complex physiological noise. To analyze two-photon brain imaging data, we present a signal plus colored noise model in which the signal is represented as harmonic regression and the correlated noise is represented as an order autoregressive process. We provide an efficient cyclic descent algorithm to compute approximate maximum likelihood parameter estimates by combing a weighted least-squares procedure with the Burg algorithm. We use Akaike information criterion to guide selection of the harmonic regression and the autoregressive model orders. Our flexible yet parsimonious modeling approach reliably separates stimulus-evoked fluorescence response from background activity and noise, assesses goodness of fit, and estimates confidence intervals and signal-to-noise ratio. This refined separation leads to appreciably enhanced image contrast for individual cells including clear delineation of subcellular details and network activity. The application of our approach to in vivo imaging data recorded in the ferret primary visual cortex demonstrates that our method yields substantially denoised signal estimates. We also provide a general Volterra series framework for deriving this and other signal plus correlated noise models for imaging. This approach to analyzing two-photon calcium imaging data may be readily adapted to other computational biology problems which apply correlated noise models.

  5. Karyotype Analysis Activity: A Constructivist Learning Design

    Science.gov (United States)

    Ahmed, Noveera T.

    2015-01-01

    This classroom activity is based on a constructivist learning design and engages students in physically constructing a karyotype of three mock patients. Students then diagnose the chromosomal aneuploidy based on the karyotype, list the symptoms associated with the disorder, and discuss the implications of the diagnosis. This activity is targeted…

  6. The Analysis of Activated Carbon Regeneration Technologies

    Institute of Scientific and Technical Information of China (English)

    姚芳

    2014-01-01

    A series of methods for activated carbon regeneration were briefly introduced.Such as thermal regeneration,chemical regeneration,biochemical regeneration,and newly supercritical fluid regeneration, electrochemical regeneration,light-catalyzed regeneration,and microwave radiation method,and the developing trend of activated carbon regeneration was predicted.

  7. Plasmonic and Photonic Modes Excitation in Graphene on Silicon Photonic Crystal Membrane

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Gu, Tingyi; Hao, Yufeng;

    Graphene is a perspective material platform for the infrared (from far-IR to near-IR) optoelectronics due to possibility of extremely confined surface plasmons polaritons excitation at long wavelengths, and large (for atomically thin layer) optical absorbance of 2.3% in the short wavelengths rang...... characterization. Measured data are well correlated with the numerical analysis. Combined graphene – silicon photonic crystal membranes can find applications for infrared absorbers, modulators, filters, sensors and photodetectors........ Being deposited on a silicon photonic crystal membrane graphene serves as a highly promising system for modern optoelectronics with rich variety of possible regimes. Depending on the relation between the photonic crystal lattice constant and wavelengths (plasmonic, photonic and free-space) we identify...... four different interaction schemes. We refer to them as metamaterial, plasmonic, photonic and diffraction grating regimes based on the principle character of light interactions with the graphene deposited on the Si photonic crystal membrane. The optimal configurations for resonant excitation of modes...

  8. A monolithic integrated photonic microwave filter

    Science.gov (United States)

    Fandiño, Javier S.; Muñoz, Pascual; Doménech, David; Capmany, José

    2016-12-01

    Meeting the increasing demand for capacity in wireless networks requires the harnessing of higher regions in the radiofrequency spectrum, reducing cell size, as well as more compact, agile and power-efficient base stations that are capable of smoothly interfacing the radio and fibre segments. Fully functional microwave photonic chips are promising candidates in attempts to meet these goals. In recent years, many integrated microwave photonic chips have been reported in different technologies. To the best of our knowledge, none has monolithically integrated all the main active and passive optoelectronic components. Here, we report the first demonstration of a tunable microwave photonics filter that is monolithically integrated into an indium phosphide chip. The reconfigurable radiofrequency photonic filter includes all the necessary elements (for example, lasers, modulators and photodetectors), and its response can be tuned by means of control electric currents. This is an important step in demonstrating the feasibility of integrated and programmable microwave photonic processors.

  9. Detailed Analysis of Motor Unit Activity

    DEFF Research Database (Denmark)

    Nikolic, Mile; Sørensen, John Aasted; Dahl, Kristian

    1997-01-01

    System for decomposition of EMG signals intotheir constituent motor unit potentials and their firing patterns.The aim of the system is detailed analysis ofmotor unit variability.......System for decomposition of EMG signals intotheir constituent motor unit potentials and their firing patterns.The aim of the system is detailed analysis ofmotor unit variability....

  10. Ultrafast photon drag detector for intersubband spectroscopy

    Science.gov (United States)

    Sigg, Hans; Graf, Stephan; Kwakernaak, Martin H.; Margotte, Bernd; Erni, Daniel; Van Son, Peter; Köhler, Klaus

    1996-03-01

    The photon drag effect of a 2D electron gas is measured using the ps infrared pulses of the wavelength-tunable free electron laser source FELIX. The pulsed photon drag response is found to depend critically on the coupling characteristics of the electrical circuit. We therefore developed an impedance and velocity matched photon drag detector. It consists of a GaAs/AlGaAs multi quantum well sample which forms an integral part of a microstrip line. A Ge-prism enables incoupling at the critical total reflection angle. This novel transmission line integrated photon drag detector (TIP-detector) generates signal transients below 10 ps rise and fall times. Its continuous spectral response through the intersubband resonance is investigated at room temperature and at T=100 K. An analysis of the spectral lineshape of the photon drag current response yields information about the momentum relaxation times of the electrons in the ground and excited subbands.

  11. Characterization of APDs for single photon counting

    Energy Technology Data Exchange (ETDEWEB)

    Buglak, Wladimir; Hannen, Volker; Joehren, Raphael; Surholt, Martin; Vollbrecht, Jonas; Weinheimer, Christian [Muenster Univ. (Germany). Inst. fuer Kernphysik; Noertershaeuser, Wilfried [Mainz Univ. (Germany). Inst. fuer Kernchemie; GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Sanchez, Rodolfo [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany)

    2013-07-01

    For the SPECTRAP experiment at GSI, Germany, a detector system with single-photon counting capability operating in the wavelength region from 300 nm up to 1100 nm has been developed at the University of Muenster. The detector system utilises a silicon avalanche photo diode (APD) cooled to liquid nitrogen temperatures and operated near the breakdown voltage to obtain high gain values. While the current setup uses a 2 x 2 mm{sup 2} APD (type RMD S0223), it would be advantageous to have a larger active area for easier adjustment of the experiment optics. On the other hand a larger active area is accompanied by increased thermal noise which might harm the photon counting performance of the device. The characterization of a 8 x 8 mm{sup 2} APD (RMD S0814) is the subject of this poster. Furthermore a signal analysis software was developed to supress noise signals, e.g. caused by microphonic effects. The software processes signal waveforms recorded by a Flash ADC and should allow for a lower trigger threshold and thus higher detection efficiency.

  12. Photon and electron identification with the ATLAS detector

    CERN Document Server

    Cerda Alberich, Leonor; The ATLAS collaboration

    2016-01-01

    Photon and electron identifications are a crucial input to many ATLAS physics analysis. The identification of prompt photons and the rejection of background coming mostly from photons from hadron decays relies on the high granularity of the ATLAS calorimeter. The electron identification used in ATLAS for run 2 is based on a likelihood discrimination combining calorimeter and track variables to separate isolated electron candidates from candidates originating from photon conversions, hadron misidentification and heavy flavor decays. In addition, isolation variables are used as further handles to separate signal and background. Several methods are used to measure with data the efficiency of the photon identification requirements, to cover a broad energy spectrum. At low energy, photons from radiative Z decays are used. In the medium energy range, similarities between electrons and photon showers are exploited using Z->ee decays. At high energy, inclusive photon samples are used. The measurement of the efficienc...

  13. Development of educational program for neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Yong Sam; Moon, Jong Hwa; Kim, Sun Ha; Ryel, Sung; Kang, Young Hwan; Lee, Kil Yong; Yeon, Yeon Yel; Cho, Seung Yeon

    2000-08-01

    This technical report is developed to apply an educational and training program for graduate student and analyst utilizing neutron activation analysis. The contents of guide book consists of five parts as follows; introduction, gamma-ray spectrometry and measurement statistics, its applications, to understand of comprehensive methodology and to utilize a relevant knowledge and information on neutron activation analysis.

  14. Photonic Crystal Fiber Based Entangled Photon Sources

    Science.gov (United States)

    2014-03-01

    new entanglement source is to make sure the source can provide an efficient and scalable quantum information processor . They are usually generated...multiple scattering on the telecom wavelength photon-pair. Our findings show that quantum correlation of polarization-entangled photon-pairs is...Fiber, Quantum communication, Keyed Communication in Quantum Noise (KCQ) 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18

  15. Multiplexing photons with a binary division strategy

    Science.gov (United States)

    Schmiegelow, Christian Tomás; Larotonda, Miguel Antonio

    2014-08-01

    We present a scheme to produce clock-synchronized photons from a single parametric downconversion source with a binary division strategy. The time difference between a clock and detections of the herald photons determines the amount of delay that must be imposed to a photon by actively switching different temporal segments, so that all photons emerge from the output with their wavepackets temporally synchronized with the temporal reference. The operation is performed using a binary division configuration which minimizes the passages through switches. Finally, we extend this scheme to the production of many synchronized photons and find expressions for the optimal amount of correction stages as a function of the pair generation rate and the target coherence time. Our results show that, for the generation of this heralded single-photon per output state at an optimized input photon flux, the output rate of our scheme scales essentially with the reciprocal of the target output photon number. With current technology, rates of up to 104 synchronized pairs per second could be observed with only 7 correction stages.

  16. UK photonics in defence and security

    Science.gov (United States)

    Gracie, C.; Tooley, I.; Wilson, A.

    2008-10-01

    The UK is globally recognised as strong in Photonics. However its Photonics sector is fragmented and the size and sectors of interest have not previously been established. The UK government has instigated the formation of the Photonics Knowledge Transfer Network (PKTN) to bring the Photonics community together. The UK features in Defence & Security; Communications; Measurement; Medical Technology; Lighting; Solar Energy; Information Technology and Flat Panels. This expertise is scattered through out the UK in geographic areas each with a breadth of Photonic interests. The PKTN has mapped the UK capability in all Photonics sectors. This paper will present the capability of the Companies, Research Institutions and Infrastructure making up the Defence & Security Photonics scene in the UK. Large Defence companies in the UK are well known throughout the world. However, there are a large number of SMEs, which may not be as well known in the supply chain. These are being actively encouraged by the UK MoD to engage with the Defence & Security Market and shall be discussed here. The presentation will reference a number of organisations which help to fund and network the community, such as the Defence Technology Centres. In addition the Roadmap for Defence & Security in the UK, produced for the UK Photonics Strategy (July 2006) by the Scottish Optoelectronics Association will be described and the plans in taking it forward under the PKTN will be revealed.

  17. Regenerative photonic therapy: Review

    Science.gov (United States)

    Salansky, Natasha; Salansky, Norman

    2012-09-01

    After four decades of research of photobiomodulation phenomena in mammals in vitro and in vivo, a solid foundation is created for the use of photobiomodulation in regenerative medicine. Significant accomplishments are achieved in animal models that demonstrate opportunities for photo-regeneration of injured or pathological tissues: skin, muscles and nerves. However, the use of photobiomodulation in clinical studies leads to controversial results while negative or marginal clinical efficacy is reported along with positive findings. A thor ough analysis of requirements to the optical parameters (dosimetry) for high efficacy in photobimodulation led us to the conclusion that there are several misconceptions in the clinical applications of low level laser therapy (LLLT). We present a novel appr oach of regenerative photonic therapy (RPT) for tissue healing and regeneration that overcomes major drawbacks of LLLT. Encouraging clinical results on RPT efficacy are presented. Requirements for RPT approach and vision for its future development for tissue regeneration is discussed.

  18. Vasodilation by in vivo activation of astrocyte endfeet via two-photon calcium uncaging as a strategy to prevent brain ischemia

    Science.gov (United States)

    Chen, Yuanxin; Mancuso, James; Zhao, Zhen; Li, Xuping; Cheng, Jie; Roman, Gustavo; Wong, Stephen T. C.

    2013-12-01

    Decreased cerebral blood flow causes brain ischemia and plays an important role in the pathophysiology of many neurodegenerative diseases, including Alzheimer's disease and vascular dementia. In this study, we photomodulated astrocytes in the live animal by a combination of two-photon calcium uncaging in the astrocyte endfoot and in vivo imaging of neurovasculature and astrocytes by intravital two-photon microscopy after labeling with cell type specific fluorescent dyes. Our study demonstrates that photomodulation at the endfoot of a single astrocyte led to a 25% increase in the diameter of a neighboring arteriole, which is a crucial factor regulating cerebral microcirculation in downstream capillaries. Two-photon uncaging in the astrocyte soma or endfoot near veins does not show the same effect on microcirculation. These experimental results suggest that infrared photomodulation on astrocyte endfeet may be a strategy to increase cerebral local microcirculation and thus prevent brain ischemia.

  19. Activity Landscape Plotter: A Web-based Application for the Analysis of Structure-Activity Relationships.

    Science.gov (United States)

    González-Medina, Mariana; Méndez-Lucio, Oscar; Medina-Franco, Jose Luis

    2017-02-24

    Activity landscape modeling is a powerful method for the quantitative analysis of structure-activity relationships. This cheminformatics area is in continuous growth and several quantitative and visual approaches are constantly being developed. However, these approaches often fall into disuse due to their limited access. Herein, we present Activity Landscape Plotter as the first freely available web-based tool to automatically analyze structure-activity relationships of compound data sets. Based on the concept of activity landscape modeling, the online service performs pair-wise structure and activity relationships from an input data set supplied by the user. For visual analysis, Activity Landscape Plotter generates Structure-Activity Similarity and Dual Activity Difference maps. The user can interactively navigate through the maps and export all the pairwise structure-activity information as comma delimited files. Activity Landscape Plotter is freely accessible at https://unam-shiny-difacquim.shinyapps.io/ActLSmaps/.

  20. Teaching-Learning Activity Modeling Based on Data Analysis

    Directory of Open Access Journals (Sweden)

    Kyungrog Kim

    2015-03-01

    Full Text Available Numerous studies are currently being carried out on personalized services based on data analysis to find and provide valuable information about information overload. Furthermore, the number of studies on data analysis of teaching-learning activities for personalized services in the field of teaching-learning is increasing, too. This paper proposes a learning style recency-frequency-durability (LS-RFD model for quantified analysis on the level of activities of learners, to provide the elements of teaching-learning activities according to the learning style of the learner among various parameters for personalized service. This is to measure preferences as to teaching-learning activity according to recency, frequency and durability of such activities. Based on the results, user characteristics can be classified into groups for teaching-learning activity by categorizing the level of preference and activity of the learner.

  1. Faculty Activity Analysis in the Universidad Tecnica Del Estado Campuses.

    Science.gov (United States)

    Karadima, Oscar

    An analysis of academic activities of college faculty at the eight campuses of Chile's Universidad Tecnica del Estado was conducted. Activities were grouped into seven categories: direct teaching, indirect teaching, research, community services, faculty development, academic administration, and other activities. Following the narrative…

  2. Interfering Heralded Single Photons from Two Separate Silicon Nanowires Pumped at Different Wavelengths

    Directory of Open Access Journals (Sweden)

    Xiang Zhang

    2016-08-01

    Full Text Available Practical quantum photonic applications require on-demand single photon sources. As one possible solution, active temporal and wavelength multiplexing has been proposed to build an on-demand single photon source. In this scheme, heralded single photons are generated from different pump wavelengths in many temporal modes. However, the indistinguishability of these heralded single photons has not yet been experimentally confirmed. In this work, we achieve 88% ± 8% Hong–Ou–Mandel quantum interference visibility from heralded single photons generated from two separate silicon nanowires pumped at different wavelengths. This demonstrates that active temporal and wavelength multiplexing could generate indistinguishable heralded single photons.

  3. Insurer’s activity as object of economic analysis

    Directory of Open Access Journals (Sweden)

    O.O. Poplavskiy

    2015-12-01

    Full Text Available The article is devoted to the substantiation of theoretical fundamentals of insurer’s analysis and peculiarities of its implementation. The attention has been focused on the important role of economic analysis in economic science which is confirmed by its active use in research and practical orientation. The author summarizes the classification and principles of insurer’s activity analysis, supplements it with specific principles for insurer’s environment, publicity and risk-orientation which enable increasingly to take into account the peculiarities of insurance relations. The paper pays attention to the specification of elements of analysis and its key directions including the analysis of insurer’s financing, the analysis of insurance operations and the analysis of investment activity which will allow the effective functioning of risk management system.

  4. Introduction of Prompt Gamma Thermal Neutron Activation Analysis at CARR

    Institute of Scientific and Technical Information of China (English)

    WANG; Xing-hua; XIAO; Cai-jin; ZHANG; Gui-ying; YAO; Yong-gang; JIN; Xiang-chun; WANG; Ping-sheng; HUA; Long; NI; Bang-fa

    2013-01-01

    CARR will provide with maximal neutron flux in Asia,the third of the world.By using the high quality neutron beam and the advanced international experience,Prompt Gamma Neutron Activation Analysis(PGNAA)facility will be setup at high level.PGNAA on CARR will promote the development of nuclear analysis technology and improve Chinese status in the nuclear analysis field.

  5. Hybrid photon detectors

    CERN Document Server

    D'Ambrosio, C

    2003-01-01

    Hybrid photon detectors detect light via vacuum photocathodes and accelerate the emitted photoelectrons by an electric field towards inversely polarized silicon anodes, where they are absorbed, thus producing electron-hole pairs. These, in turn, are collected and generate electronic signals on their ohmic contacts. This review first describes the characteristic properties of the main components of hybrid photon detectors: light entrance windows, photocathodes, and silicon anodes. Then, essential relations describing the trajectories of photoelectrons in electric and magnetic fields and their backscattering from the silicon anodes are derived. Depending on their anode configurations, three families of hybrid photon detectors are presented: hybrid photomultiplier tubes with single anodes for photon counting with high sensitivity and for gamma spectroscopy; multi-anode photon detector tubes with anodes subdivided into square or hexagonal pads for position-sensitive photon detection; imaging silicon pixel array t...

  6. Single-photon imaging

    CERN Document Server

    Seitz, Peter

    2011-01-01

    The acquisition and interpretation of images is a central capability in almost all scientific and technological domains. In particular, the acquisition of electromagnetic radiation, in the form of visible light, UV, infrared, X-ray, etc. is of enormous practical importance. The ultimate sensitivity in electronic imaging is the detection of individual photons. With this book, the first comprehensive review of all aspects of single-photon electronic imaging has been created. Topics include theoretical basics, semiconductor fabrication, single-photon detection principles, imager design and applications of different spectral domains. Today, the solid-state fabrication capabilities for several types of image sensors has advanced to a point, where uncoooled single-photon electronic imaging will soon become a consumer product. This book is giving a specialist´s view from different domains to the forthcoming “single-photon imaging” revolution. The various aspects of single-photon imaging are treated by internati...

  7. Photon strength function deduced from photon scattering and neutron capture

    Directory of Open Access Journals (Sweden)

    Matic A.

    2010-10-01

    Full Text Available The dipole strength function of 78Se and 196Pt are investigated by two different experimental methods, capture of cold neutrons in 77Se and 195Pt and photon scattering experiments on 78Se and 196Pt. Considering the different ways of excitation, the strength function deduced from the results are expected to agree. The report shows the status of the data analysis and presents first preliminary results.

  8. Opportunities for innovation in neutron activation analysis

    NARCIS (Netherlands)

    Bode, P.

    2011-01-01

    Neutron activation laboratories worldwide are at a turning point at which new staff has to be found for the retiring pioneers from the 1960s–1970s. A scientific career in a well-understood technique, often characterized as ‘mature’ may only be attractive to young scientists if still challenges for f

  9. Design professional activity analysis in design management

    Directory of Open Access Journals (Sweden)

    Claudia de Souza Libanio

    2013-08-01

    Full Text Available Design use perception, as an essential element for achieving competitive advantage, also suggests the need to manage the design activities in companies. However, a few is discussed about the activity of these design professionals who participate in this process, their roles, functions and competencies, including  their connections to a company and other involved sectors. This article aims to analyze, during the design management processes, the work relations of design professionals connected to organizations both internal and externally, in order to comprehend the structure and intervenient factors on the activity of these professionals, as well as the interactions with their main coworkers. The methodology was exploratory and qualitative, using in-depth interviews with three design professionals. Subsequently, the responses were analyzed allowing the comparison of these obtained data to the theoretical bases researched. Through this case study, it was possible to realize the aspects and the structure of the design professional activity, connected intern and externally to organizations, as well as its relations with the main coworkers.

  10. Reevaluation of photon activation yields of {sup 11}C. {sup 13}N, and {sup 15}O for the estimation of activity in gas and water induced by the operation of electron accelerates for medical use

    Energy Technology Data Exchange (ETDEWEB)

    Masumoto, Kazuyoshi; Matsumura, Hiroshi; Bessho, Kotaro; Toyoda, Akihiro [High Energy Accelerator Research Organization, Tsukuba (Japan); Kasako, Kazuaki [Shimizu Corporation, Tokyo (Japan)

    2016-09-15

    Activation of air and water in the electron linear accelerator for medical use has not been considered severely. By the new Japanese regulation for protection of radiation hazard, it became indispensable to evaluate of activation of air and water in the accelerator room. The measurement of induced activity in air and water components in the electron energy region of 10 to 20 MeV is very difficult, because this energy region is close to the threshold energy region of photonuclear reactions. Then, we measured the photonuclear reaction yields of {sup 13}N,{sup 15}O, and {sup 11}C by using the electron linear accelerator. Obtained data were compared with the data calculated by the Monte Carlo method. An activation experiment was performed at the Research Center for Electron Photon Science, Tohoku University. Highly purified SiO{sub 2}, Si{sub 3}N{sub 4}, and carbon disks were irradiated for 10 minutes by Bremsstrahlung converted by a tungsten plate. Induced activity from C, N, and O was obtained. Monte Carlo calculation was performed using MCNP5 and AERY (DCHAIN-SP) to simulate the experimental condition. Cross section data were adopted the KAERI dataset. In our experiment in hospital, calculated values were not agreed with experimental values. It might be three possible reasons as the cause of this deference, such as irradiation energy, calculation procedure and cross section data. Obtained data of this work, calculated and experimental values were good agreement with each other within one order. In this work, we used KAERI dataset of photonuclear reaction instead of JENDL. Therefore, it was found that the photonuclear cross section data of light elements are most important for yield calculation in these reactions. Further improvement for calculation using a new dataset JENDL/PD-2015 and considering electron energy spreading will be needed.

  11. Active Shape Analysis of Mandibular Growth

    DEFF Research Database (Denmark)

    Hilger, Klaus Baggesen; Larsen, Rasmus; Kreiborg, Sven;

    2003-01-01

    This work contains a clinical validation using biological landmarks of a Geometry Constrained Diffusion registration of mandibular surfaces. Canonical Correlations Analysis is extended to analyse 3D landmarks and the correlations are used as similarity measures for landmark clustering. A novel Ac...

  12. X-ray spectrophotometer SphinX and particle spectrometer STEP-F of the satellite experiment CORONAS-PHOTON. Preliminary results of the joint data analysis

    Science.gov (United States)

    Dudnik, O. V.; Podgorski, P.; Sylwester, J.; Gburek, S.; Kowalinski, M.; Siarkowski, M.; Plocieniak, S.; Bakala, J.

    2012-04-01

    A joint analysis is carried out of data obtained with the help of the solar X-ray SphinX spectrophotometer and the electron and proton satellite telescope STEP-F in May 2009 in the course of the scientific space experiment CORONAS-PHOTON. In order to determine the energies and particle types, in the analysis of spectrophotometer records data are used on the intensities of electrons, protons, and secondary γ-radiation, obtained by the STEP-F telescope, which was located in close proximity to the SphinX spectrophotometer. The identical reaction of both instruments is noted at the intersection of regions of the Brazilian magnetic anomaly and the Earth's radiation belts. It is shown that large area photodiodes, serving as sensors of the X-ray spectrometer, reliably record electron fluxes of low and intermediate energies, as well as fluxes of the secondary gamma radiation from construction materials of detector modules, the TESIS instrument complex, and the spacecraft itself. The dynamics of electron fluxes, recorded by the SphinX spectrophotometer in the vicinity of a weak geomagnetic storm, supplements the information about the processes of radial diffusion of electrons, which was studied using the STEP-F telescope.

  13. Two-photon physics

    Energy Technology Data Exchange (ETDEWEB)

    Bardeen, W.A.

    1981-10-01

    A new experimental frontier has recently been opened to the study of two photon processes. The first results of many aspects of these reactions are being presented at this conference. In contrast, the theoretical development of research ito two photon processes has a much longer history. This talk reviews the many different theoretical ideas which provide a detailed framework for our understanding of two photon processes.

  14. Advanced Photon Source (APS)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Photon Source (APS) at the U.S. Department of Energy's Argonne National Laboratoryprovides this nation's (in fact, this hemisphere's) brightest storage...

  15. Effects of Longitudinal Photons

    CERN Document Server

    Friberg, C; Friberg, Christer; Sjöstrand, Torbjörn

    2000-01-01

    The description of longitudinal photons is far from trivial, and their phenomenological importance is largely unknown. While the cross section for direct interactions is calculable, an even more important contribution could come from resolved states. In the development of our model for the interactions of (real and) virtual photons, we have modeled resolved longitudinal effects by simple multiplicative factors on the resolved transverse-photon contributions. Recently, a first set of parton distributions for longitudinal virtual photons has been presented by Ch\\'yla. We therefore compare their impact on some representative distributions, relative to the simpler approaches.

  16. Photonic Integrated Circuits

    Science.gov (United States)

    Krainak, Michael; Merritt, Scott

    2016-01-01

    Integrated photonics generally is the integration of multiple lithographically defined photonic and electronic components and devices (e.g. lasers, detectors, waveguides passive structures, modulators, electronic control and optical interconnects) on a single platform with nanometer-scale feature sizes. The development of photonic integrated circuits permits size, weight, power and cost reductions for spacecraft microprocessors, optical communication, processor buses, advanced data processing, and integrated optic science instrument optical systems, subsystems and components. This is particularly critical for small spacecraft platforms. We will give an overview of some NASA applications for integrated photonics.

  17. Integrated microwave photonics

    CERN Document Server

    Marpaung, David; Heideman, Rene; Leinse, Arne; Sales, Salvador; Capmany, Jose

    2012-01-01

    Microwave photonics (MWP) is an emerging field in which radio frequency (RF) signals are generated, distributed, processed and analyzed using the strength of photonic techniques. It is a technology that enables various functionalities which are not feasible to achieve only in the microwave domain. A particular aspect that recently gains significant interests is the use of photonic integrated circuit (PIC) technology in the MWP field for enhanced functionalities and robustness as well as the reduction of size, weight, cost and power consumption. This article reviews the recent advances in this emerging field which is dubbed as integrated microwave photonics. Key integrated MWP technologies are reviewed and the prospective of the field is discussed.

  18. Biomedical photonics handbook

    CERN Document Server

    Vo-Dinh, Tuan

    2003-01-01

    1.Biomedical Photonics: A Revolution at the Interface of Science and Technology, T. Vo-DinhPHOTONICS AND TISSUE OPTICS2.Optical Properties of Tissues, J. Mobley and T. Vo-Dinh3.Light-Tissue Interactions, V.V. Tuchin 4.Theoretical Models and Algorithms in Optical Diffusion Tomography, S.J. Norton and T. Vo-DinhPHOTONIC DEVICES5.Laser Light in Biomedicine and the Life Sciences: From the Present to the Future, V.S. Letokhov6.Basic Instrumentation in Photonics, T. Vo-Dinh7.Optical Fibers and Waveguides for Medical Applications, I. Gannot and

  19. Review on Dark Photon

    Directory of Open Access Journals (Sweden)

    Curciarello Francesca

    2016-01-01

    Full Text Available e+e− collider experiments at the intensity frontier are naturally suited to probe the existence of a force beyond the Standard Model between WIMPs, the most viable dark matter candidates. The mediator of this new force, known as dark photon, should be a new vector gauge boson very weakly coupled to the Standard Model photon. No significant signal has been observed so far. I will report on current limits set on the coupling factor ε2 between the photon and the dark photon by e+e− collider experiments.

  20. Digital image processing and analysis for activated sludge wastewater treatment.

    Science.gov (United States)

    Khan, Muhammad Burhan; Lee, Xue Yong; Nisar, Humaira; Ng, Choon Aun; Yeap, Kim Ho; Malik, Aamir Saeed

    2015-01-01

    Activated sludge system is generally used in wastewater treatment plants for processing domestic influent. Conventionally the activated sludge wastewater treatment is monitored by measuring physico-chemical parameters like total suspended solids (TSSol), sludge volume index (SVI) and chemical oxygen demand (COD) etc. For the measurement, tests are conducted in the laboratory, which take many hours to give the final measurement. Digital image processing and analysis offers a better alternative not only to monitor and characterize the current state of activated sludge but also to predict the future state. The characterization by image processing and analysis is done by correlating the time evolution of parameters extracted by image analysis of floc and filaments with the physico-chemical parameters. This chapter briefly reviews the activated sludge wastewater treatment; and, procedures of image acquisition, preprocessing, segmentation and analysis in the specific context of activated sludge wastewater treatment. In the latter part additional procedures like z-stacking, image stitching are introduced for wastewater image preprocessing, which are not previously used in the context of activated sludge. Different preprocessing and segmentation techniques are proposed, along with the survey of imaging procedures reported in the literature. Finally the image analysis based morphological parameters and correlation of the parameters with regard to monitoring and prediction of activated sludge are discussed. Hence it is observed that image analysis can play a very useful role in the monitoring of activated sludge wastewater treatment plants.

  1. Assessment of neuroinflammation and microglial activation in Alzheimer's disease with radiolabelled PK11195 and single photon emission computed tomography - A Pilot Study

    NARCIS (Netherlands)

    Versijpt, JJ; Dumont, F; Van Laere, KJ; Decoo, D; Santens, P; Audenaert, K; Achten, E; Slegers, G; Dierckx, RA; Korf, J

    2003-01-01

    Objectives: Inflammation contributes to degeneration in Alzheimer's disease (AD), not simply as a secondary phenomenon, but primarily as a significant source of pathology. [I-123]iodo-PK11195 is a single photon emission computed tomography (SPECT) ligand for the peripheral benzodiazepine receptor, t

  2. Computational Models for Analysis of Illicit Activities

    DEFF Research Database (Denmark)

    Nizamani, Sarwat

    result in a fully evolved network. This method of network evolution can help intelligence security analysts to understand the structure of the network. For suspicious emails detection and email author identification, a cluster-based text classification model has been proposed. The model outperformed...... traditional models for both of the tasks. Apart from these globally organized crimes and cybercrimes, there happen specific world issues which affect geographic locations and take the form of bursts of public violence. These kinds of issues have received little attention by the academicians. These issues have...... to describe the phenomenon of contagious public outrage, which eventually leads to the spread of violence following a disclosure of some unpopular political decisions and/or activity. The results shed a new light on terror activity and provide some hint on how to curb the spreading of violence within...

  3. Automatic Quenching of High Energy gamma-ray Sources by Synchrotron Photons

    Energy Technology Data Exchange (ETDEWEB)

    Stawarz, Lukasz; /KIPAC, Menlo Park /SLAC /Jagiellonian U., Astron. Observ.; Kirk, John; /Heidelberg, Max Planck Inst.

    2007-02-02

    Here we investigate evolution of a magnetized system, in which continuously produced high energy emission undergoes annihilation on a soft photon field, such that the synchrotron radiation of the created electron-positron pairs increases number density of the soft photons. This situation is important in high energy astrophysics, because, for an extremely wide range of magnetic field strengths (nano to mega Gauss), it involves {gamma}-ray photons with energies between 0.3GeV and 30TeV. We derive and analyze the conditions for which the system is unstable to runaway production of soft photons and ultrarelativistic electrons, and for which it can reach a steady state with an optical depth to photon-photon annihilation larger than unity, as well those for which efficient pair loading of the emitting volume takes place. We also discuss the application of our analysis to a realistic situation involving astrophysical sources of a broad-band {gamma}-ray emission and briefly consider the particular case of sources close to active supermassive black holes.

  4. Regulatory activities of government: analysis of determinants

    Directory of Open Access Journals (Sweden)

    Primož Pevcin

    2006-12-01

    Full Text Available International comparisons show that large cross-country differences exist in the overall macro extent of regulation of the economy. In this context, the main purpose of the article is to investigate, why such differences exist by identifying and empirically verifying the effect of various factors that could potentially shape those differences. Empirical analysis based on the sample of 32 developed and democratic countries revealed that almost 70 % of variation in the macro extent of regulation could be explained with 7 statistically significant explanatory variables. The econometric analysis revealed that the macro extent of regulation decreases with income inequality in society, with the level of economic development, with the sizeof economy, with the share of transfer spending in GDP and with the share of government employment in labour force. On the other hand, the extent of regulation is positively related to government ownership of enterprises and to presidential political regime

  5. The research and progress of micro-fabrication technologies of two-dimensional photonic crystal

    Institute of Scientific and Technical Information of China (English)

    XU XingSheng; ZHANG DaoZhong

    2007-01-01

    The novel material of photonic crystal makes it possible to control a photon, and the photonic integration will have breakthrough progress due to the application of photonic crystal. It is based on the photonic crystal device that the photonic crystal integration could be realized. Therefore, we should first investigate photonic crystal devices based on the active and the passive semiconductor materials,which may have great potential application in photonic integration. The most practical and important method to fabricate two-dimensional photonic crystal is the micro-manufacture method. In this paper,we summarize and evaluate the fabrication methods of two-dimensional photonic crystal in near-infrared region, including electron beam lithography, selection of mask, dry etching, and some works of ours. This will be beneficial to the study of the photonic crystal in China.

  6. Active vision in satellite scene analysis

    Science.gov (United States)

    Naillon, Martine

    1994-01-01

    In earth observation or planetary exploration it is necessary to have more and, more autonomous systems, able to adapt to unpredictable situations. This imposes the use, in artificial systems, of new concepts in cognition, based on the fact that perception should not be separated from recognition and decision making levels. This means that low level signal processing (perception level) should interact with symbolic and high level processing (decision level). This paper is going to describe the new concept of active vision, implemented in Distributed Artificial Intelligence by Dassault Aviation following a 'structuralist' principle. An application to spatial image interpretation is given, oriented toward flexible robotics.

  7. Mathematical analysis of complex cellular activity

    CERN Document Server

    Bertram, Richard; Teka, Wondimu; Vo, Theodore; Wechselberger, Martin; Kirk, Vivien; Sneyd, James

    2015-01-01

    This book contains two review articles on mathematical physiology that deal with closely related topics but were written and can be read independently. The first article reviews the basic theory of calcium oscillations (common to almost all cell types), including spatio-temporal behaviors such as waves. The second article uses, and expands on, much of this basic theory to show how the interaction of cytosolic calcium oscillators with membrane ion channels can result in highly complex patterns of electrical spiking. Through these examples one can see clearly how multiple oscillatory processes interact within a cell, and how mathematical methods can be used to understand such interactions better. The two reviews provide excellent examples of how mathematics and physiology can learn from each other, and work jointly towards a better understanding of complex cellular processes. Review 1: Richard Bertram, Joel Tabak, Wondimu Teka, Theodore Vo, Martin Wechselberger: Geometric Singular Perturbation Analysis of Burst...

  8. Photonic Crystal Fiber Attenuator

    Institute of Scientific and Technical Information of China (English)

    Joo; Beom; Eom; Hokyung; Kim; Jinchae; Kim; Un-Chul; Paek; Byeong; Ha; Lee

    2003-01-01

    We propose a novel fiber attenuator based on photonic crystal fibers. The difference in the modal field diameters of a conventional single mode fiber and a photonic crystal fiber was used. A variable optical attenuator was also achieved by applying macro-bending on the PCF part of the proposed attenuator

  9. Photon mass from inflation.

    Science.gov (United States)

    Prokopec, Tomislav; Törnkvist, Ola; Woodard, Richard

    2002-09-01

    We consider vacuum polarization from massless scalar electrodynamics in de Sitter inflation. The theory exhibits a 3+1 dimensional analog of the Schwinger mechanism in which a photon mass is dynamically generated. The mechanism is generic for light scalar fields that couple minimally to gravity. The nonvanishing of the photon mass during inflation may result in magnetic fields on cosmological scales.

  10. Superconducting Single Photon Detectors

    NARCIS (Netherlands)

    Dorenbos, S.N.

    2011-01-01

    This thesis is about the development of a detector for single photons, particles of light. New techniques are being developed that require high performance single photon detection, such as quantum cryptography, single molecule detection, optical radar, ballistic imaging, circuit testing and fluoresc

  11. ALICE Photon Multiplicity Detector

    CERN Multimedia

    Nayak, T

    2013-01-01

    Photon Multiplicity Detector (PMD) measures the multiplicity and spatial distribution of photons in the forward region of ALICE on a event-by-event basis. PMD is a pre-shower detector having fine granularity and full azimuthal coverage in the pseudo-rapidity region 2.3 < η < 3.9.

  12. Diffusion Based Photon Mapping

    DEFF Research Database (Denmark)

    Schjøth, Lars; Sporring, Jon; Fogh Olsen, Ole

    2008-01-01

    . To address this problem, we introduce a photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way, we preserve important illumination features, while...

  13. Theory of antibunching of photon emission II.

    Science.gov (United States)

    Seki, Kazuhiko; Tachiya, M

    2009-05-21

    Recently single photon emission has been observed for systems in which multiple excitons are generated by pulsed excitation. When fast pair annihilation of excitons takes place, finally a single exciton remains and single photon can be emitted. Its efficiency depends on the competition among pair annihilation, unimolecular nonradiative, and radiative processes. The efficiency of single photon emission is usually studied by measuring the correlation of emitted photons after pulsed excitation by the Hanbury-Brown and Twiss method. The photon correlation measured in this method is different from that calculated by taking into account all pairs of emitted photons, which was presented in a previous paper. We calculate the former rigorously for the first time in the case of multiple excitations and compare it with the latter. We also calculate correlation of arrival times of two photons by the Hanbury-Brown and Twiss method. These results should be useful for the analysis of the antibunching measurement by the Hanbury-Brown and Twiss method.

  14. Correlating two-photon excited fluorescence imaging of breast cancer cellular redox state with seahorse flux analysis of normalized cellular oxygen consumption

    Science.gov (United States)

    Hou, Jue; Wright, Heather J.; Chan, Nicole; Tran, Richard; Razorenova, Olga V.; Potma, Eric O.; Tromberg, Bruce J.

    2016-06-01

    Two-photon excited fluorescence (TPEF) imaging of the cellular cofactors nicotinamide adenine dinucleotide and oxidized flavin adenine dinucleotide is widely used to measure cellular metabolism, both in normal and pathological cells and tissues. When dual-wavelength excitation is used, ratiometric TPEF imaging of the intrinsic cofactor fluorescence provides a metabolic index of cells-the "optical redox ratio" (ORR). With increased interest in understanding and controlling cellular metabolism in cancer, there is a need to evaluate the performance of ORR in malignant cells. We compare TPEF metabolic imaging with seahorse flux analysis of cellular oxygen consumption in two different breast cancer cell lines (MCF-7 and MDA-MB-231). We monitor metabolic index in living cells under both normal culture conditions and, for MCF-7, in response to cell respiration inhibitors and uncouplers. We observe a significant correlation between the TPEF-derived ORR and the flux analyzer measurements (R=0.7901, p<0.001). Our results confirm that the ORR is a valid dynamic index of cell metabolism under a range of oxygen consumption conditions relevant for cancer imaging.

  15. Function Photonic Crystals

    CERN Document Server

    Wu, Xiang-Yao; Yang, Jing-Hai; Liu, Xiao-Jing; Ba, Nuo; Wu, Yi-Heng; Wang, Qing-Cai; Li, Jing-Wu

    2010-01-01

    In the paper, we present a new kind of function photonic crystals, which refractive index is a function of space position. Unlike conventional PCs, which structure grow from two materials, A and B, with different dielectric constants $\\epsilon_{A}$ and $\\epsilon_{B}$. By Fermat principle, we give the motion equations of light in one-dimensional, two-dimensional and three-dimensional function photonic crystals. For one-dimensional function photonic crystals, we study the dispersion relation, band gap structure and transmissivity, and compare them with conventional photonic crystals. By choosing various refractive index distribution function $n(z)$, we can obtain more width or more narrow band gap structure than conventional photonic crystals.

  16. A novel photonic oscillator

    Science.gov (United States)

    Yao, X. S.; Maleki, L.

    1995-01-01

    We report a novel oscillator for photonic RF systems. This oscillator is capable of generating high-frequency signals up to 70 GHz in both electrical and optical domains and is a special voltage-controlled oscillator with an optical output port. It can be used to make a phase-locked loop (PLL) and perform all functions that a PLL is capable of for photonic systems. It can be synchronized to a reference source by means of optical injection locking, electrical injection locking, and PLL. It can also be self-phase locked and self-injection locked to generate a high-stability photonic RF reference. Its applications include high-frequency reference regeneration and distribution, high-gain frequency multiplication, comb-frequecy and square-wave generation, carrier recovery, and clock recovery. We anticipate that such photonic voltage-controlled oscillators (VCOs) will be as important to photonic RF systems as electrical VCOs are to electrical RF systems.

  17. Chirality in photonic systems

    Science.gov (United States)

    Solnyshkov, Dmitry; Malpuech, Guillaume

    2016-10-01

    The optical modes of photonic structures are the so-called TE and TM modes that bring intrinsic spin-orbit coupling and chirality to these systems. This, combined with the unique flexibility of design of the photonic potential, and the possibility to mix photon states with excitonic resonances, sensitive to magnetic field and interactions, allows us to achieve many phenomena, often analogous to other solid-state systems. In this contribution, we review in a qualitative and comprehensive way several of these realizations, namely the optical spin Hall effect, the creation of spin currents protected by a non-trivial geometry, the Berry curvature for photons, and the photonic/polaritonic topological insulator.

  18. Photon regeneration plans

    Energy Technology Data Exchange (ETDEWEB)

    Ringwald, A.

    2006-12-15

    Precision experiments exploiting low-energy photons may yield information on particle physics complementary to experiments at high-energy colliders, in particular on new very light and very weakly interacting particles, predicted in many extensions of the standard model. Such particles may be produced by laser photons send along a transverse magnetic field. The laser polarization experiment PVLAS may have seen the first indirect signal of such particles by observing an anomalously large rotation of the polarization plane of photons after the passage through a magnetic field. This can be interpreted as evidence for photon disappearance due to particle production. There are a number of experimental proposals to test independently the particle interpretation of PVLAS. Many of them are based on the search for photon reappearance or regeneration, i.e. for ''light shining through a wall''. At DESY, the Axion-Like Particle Search (ALPS) collaboration is currently setting up such an experiment. (orig.)

  19. Photon Regeneration Plans

    CERN Document Server

    Ringwald, A

    2006-01-01

    Precision experiments exploiting low-energy photons may yield information on particle physics complementary to experiments at high-energy colliders, in particular on new very light and very weakly interacting particles, predicted in many extensions of the standard model. Such particles may be produced by laser photons send along a transverse magnetic field. The laser polarization experiment PVLAS may have seen the first indirect signal of such particles by observing an anomalously large rotation of the polarization plane of photons after the passage through a magnetic field. This can be interpreted as evidence for photon disappearance due to particle production. There are a number of experimental proposals to test independently the particle interpretation of PVLAS. Many of them are based on the search for photon reappearance or regeneration, i.e. for ``light shining through a wall''. At DESY, the Axion-Like Particle Search (ALPS) collaboration is currently setting up such an experiment.

  20. Nonlinear Photonics 2014: introduction.

    Science.gov (United States)

    Akhmediev, N; Kartashov, Yaroslav

    2015-01-12

    International Conference "Nonlinear Photonics-2014" took place in Barcelona, Spain on July 27-31, 2014. It was a part of the "Advanced Photonics Congress" which is becoming a traditional notable event in the world of photonics. The current focus issue of Optics Express contains contributions from the participants of the Conference and the Congress. The articles in this focus issue by no means represent the total number of the congress contributions (around 400). However, it demonstrates wide range of topics covered at the event. The next conference of this series is to be held in 2016 in Australia, which is the home of many researchers working in the field of photonics in general and nonlinear photonics in particular.

  1. Specific classification of financial analysis of enterprise activity

    Directory of Open Access Journals (Sweden)

    Synkevych Nadiia I.

    2014-01-01

    Full Text Available Despite the fact that one can find a big variety of classifications of types of financial analysis of enterprise activity, which differ with their approach to classification and a number of classification features and their content, in modern scientific literature, their complex comparison and analysis of existing classification have not been done. This explains urgency of this study. The article studies classification of types of financial analysis of scientists and presents own approach to this problem. By the results of analysis the article improves and builds up a specific classification of financial analysis of enterprise activity and offers classification by the following features: objects, subjects, goals of study, automation level, time period of the analytical base, scope of study, organisation system, classification features of the subject, spatial belonging, sufficiency, information sources, periodicity, criterial base, method of data selection for analysis and time direction. All types of financial analysis significantly differ with their inherent properties and parameters depending on the goals of financial analysis. The developed specific classification provides subjects of financial analysis of enterprise activity with a possibility to identify a specific type of financial analysis, which would correctly meet the set goals.

  2. ANALYSIS OF ECOLOGICAL ACTIVITY OF PODLASIE PROVINCE

    Directory of Open Access Journals (Sweden)

    Agnieszka Kisło

    2014-01-01

    Full Text Available The beginning of the period where the impact of human activity took dangerous size is considered to be 40 years of the nineteenth century. Then the large-scale production of electricity increased production of metallurgical industry and transport development. Significant changes contributed to rapid population growth and urbanization and industrialization processes. Man by intensive exploitation reduces or completely exhausted most natural resources. This has resulted in the availability criterion, which is distinguished by inexhaustible and exhaustible resources. Exhaustible resources may include solar, wind, energy, ocean currents and the energy of the Earth. Exhaustible resources, however, are the elements of nature that as a result of the operation can be completely depleted or destroyed. These resources include: water, soil, plant world, animal world natural resources. The greater the intensity of acquiring human resources, the faster will be the depleted. There is also a very important division of exhaustible resources: non-renewable resources, renewable and very difficult reproducible (living areas. Non-renewable resources are mainly minerals, such as iron ore, crude oil, coal, sulfur, natural gas, useful stones, limestone, salt, and many other minerals. After extraction resources are processed, and the bed from which they were extracted can no longer be used. It is different from renewable resources; they are characterized by the fact that over time they are reconstituted, although, for this to happen balance of the environment through the rational use must be maintained. These resources include, among others, soil, water, flora and fauna, as well as atmospheric air.

  3. Roadmap on silicon photonics

    Science.gov (United States)

    Thomson, David; Zilkie, Aaron; Bowers, John E.; Komljenovic, Tin; Reed, Graham T.; Vivien, Laurent; Marris-Morini, Delphine; Cassan, Eric; Virot, Léopold; Fédéli, Jean-Marc; Hartmann, Jean-Michel; Schmid, Jens H.; Xu, Dan-Xia; Boeuf, Frédéric; O'Brien, Peter; Mashanovich, Goran Z.; Nedeljkovic, M.

    2016-07-01

    Silicon photonics research can be dated back to the 1980s. However, the previous decade has witnessed an explosive growth in the field. Silicon photonics is a disruptive technology that is poised to revolutionize a number of application areas, for example, data centers, high-performance computing and sensing. The key driving force behind silicon photonics is the ability to use CMOS-like fabrication resulting in high-volume production at low cost. This is a key enabling factor for bringing photonics to a range of technology areas where the costs of implementation using traditional photonic elements such as those used for the telecommunications industry would be prohibitive. Silicon does however have a number of shortcomings as a photonic material. In its basic form it is not an ideal material in which to produce light sources, optical modulators or photodetectors for example. A wealth of research effort from both academia and industry in recent years has fueled the demonstration of multiple solutions to these and other problems, and as time progresses new approaches are increasingly being conceived. It is clear that silicon photonics has a bright future. However, with a growing number of approaches available, what will the silicon photonic integrated circuit of the future look like? This roadmap on silicon photonics delves into the different technology and application areas of the field giving an insight into the state-of-the-art as well as current and future challenges faced by researchers worldwide. Contributions authored by experts from both industry and academia provide an overview and outlook for the silicon waveguide platform, optical sources, optical modulators, photodetectors, integration approaches, packaging, applications of silicon photonics and approaches required to satisfy applications at mid-infrared wavelengths. Advances in science and technology required to meet challenges faced by the field in each of these areas are also addressed together with

  4. Analysis of a photon number resolving detector based on fluorescence readout of an ion Coulomb crystal quantum memory inside an optical cavity

    DEFF Research Database (Denmark)

    Clausen, Christoph; Sangouard, N.; Drewsen, M.

    2013-01-01

    The ability to detect single photons with a high efficiency is a crucial requirement for various quantum information applications. By combining the storage process of a quantum memory for photons with fluorescence-based quantum state measurement, it is, in principle, possible to achieve high...... on an ion Coulomb crystal inside a moderately high-finesse optical cavity. The cavity enhancement leads to an effective optical depth of 15 for a finesse of 3000 with only about 1500 ions interacting with the light field. We show that these values allow for essentially noiseless detection with an efficiency......-efficiency photon counting in large ensembles of atoms. The large number of atoms can, however, pose significant problems in terms of noise stemming from imperfect initial state preparation and off-resonant fluorescence. We identify and analyse a concrete implementation of a photon number resolving detector based...

  5. Neutron Activation Analysis of Inhomogeneous Large Samples; An Explorative Study

    NARCIS (Netherlands)

    Baas, H.W.

    2004-01-01

    Neutron activation analysis is a powerful technique for the determination of trace-element concentrations. Since both neutrons that are used for activation and gamma rays that are detected have a high penetrating power, the technique can be applied for relatively large samples (up to 13 L), as demon

  6. Activation and Dose Rate Analysis of 316 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    XU; Zhi-long; SUN; Zheng; LIU; Xing-min; WAN; Hai-xia

    2012-01-01

    <正>In order to conduct research on 316 stainless steel to be used in reactors, neutron activation during irradiation and dose rate after irradiation in China Experiment Fast Reactor (CEFR) are calculated and analyzed. Based on 1 g of 316 stainless steel specimen, analysis on the activity of 316 stainless steel irradiated

  7. Performance analysis of active schedules in identical parallel machine

    Institute of Scientific and Technical Information of China (English)

    Changjun WANG; Yugeng XI

    2007-01-01

    Active schedule is one of the most basic and popular concepts in production scheduling research. For identical parallel machine scheduling with jobs' dynamic arrivals, the tight performance bounds of active schedules under the measurement of four popular objectives are respectively given in this paper. Similar analysis method and conclusions can be generalized to static identical parallel machine and single machine scheduling problem.

  8. Analysis of Activity Patterns and Performance in Polio Survivors

    Science.gov (United States)

    2006-10-01

    subjective estimate of their activity level over the past week using the Physical Activity Scale for the Elderly (PASE).3 This instrument dealt with...May 2004. Talaty M. Models for Gait Analysis. 5th SIAMOC (Societa Italiana Di Analisi Del Movimento in Clinica) Congress, Loano, Italy November

  9. Project-Based Language Learning: An Activity Theory Analysis

    Science.gov (United States)

    Gibbes, Marina; Carson, Lorna

    2014-01-01

    This paper reports on an investigation of project-based language learning (PBLL) in a university language programme. Learner reflections of project work were analysed through Activity Theory, where tool-mediated activity is understood as the central unit of analysis for human interaction. Data were categorised according to the components of human…

  10. Applying an Activity System to Online Collaborative Group Work Analysis

    Science.gov (United States)

    Choi, Hyungshin; Kang, Myunghee

    2010-01-01

    This study determines whether an activity system provides a systematic framework to analyse collaborative group work. Using an activity system as a unit of analysis, the research examined learner behaviours, conflicting factors and facilitating factors while students engaged in collaborative work via asynchronous computer-mediated communication.…

  11. Applied research of environmental monitoring using instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Young Sam; Moon, Jong Hwa; Chung, Young Ju

    1997-08-01

    This technical report is written as a guide book for applied research of environmental monitoring using Instrumental Neutron Activation Analysis. The contents are as followings; sampling and sample preparation as a airborne particulate matter, analytical methodologies, data evaluation and interpretation, basic statistical methods of data analysis applied in environmental pollution studies. (author). 23 refs., 7 tabs., 9 figs.

  12. Structural Analysis Extended with Active Fault Isolation - Methods and Algorithms

    DEFF Research Database (Denmark)

    Gelso, Esteban R.; Blanke, Mogens

    2009-01-01

    on system inputs can considerably enhance fault isolability. This paper investigates this possibility of active fault isolation from a structural point of view. While such extension of the structural analysis approach was suggested earlier, algorithms and case studies were needed to explore this theory....... The paper develops algorithms for investigation of the possibilities of active structural isolation and it offers illustrative examples and a larger case study to explore the properties of active structural isolability ideas....

  13. Bright Solid State Source of Photon Triplets

    CERN Document Server

    Khoshnegar, Milad; Predojević, Ana; Dalacu, Dan; Prilmüller, Maximilian; Lapointe, Jean; Wu, Xiaohua; Tamarat, Philippe; Lounis, Brahim; Poole, Philip; Weihs, Gregor; Majedi, Hamed

    2015-01-01

    Producing advanced quantum states of light is a priority in quantum information technologies. While remarkable progress has been made on single photons and photon pairs, multipartite correlated photon states are usually produced in purely optical systems by post-selection or cascading, with extremely low efficiency and exponentially poor scaling. Multipartite states enable improved tests of the foundations of quantum mechanics as well as implementations of complex quantum optical networks and protocols. It would be favorable to directly generate these states using solid state systems, for better scaling, simpler handling, and the promise of reversible transfer of quantum information between stationary and flying qubits. Here we use the ground states of two optically active coupled quantum dots to directly produce photon triplets. The wavefunctions of photogenerated excitons localized in these ground states are correlated via molecular hybridization and Coulomb interactions. The formation of a triexciton leads...

  14. Massive photons in cosmology: a thermodynamical approach

    CERN Document Server

    Cuzinatto, R R; Medeiros, L G; de Souza, C Naldoni; Pimentel, B M

    2016-01-01

    We investigate the influence of massive photons on the evolution of the expanding universe. The analysis is performed assuming that the only relevant component in the universe is radiation. Two particular models for generalized electrodynamics are considered, namely Proca field and Podolsky electrodynamics. We obtain the equation of state (EOS) $P=P(\\varepsilon)$ for each case using the dispersion relation derived from both theories. The EOS are inputted into the Friedmann equations of a homogeneous and isotropic space-time to determine the cosmic scale factor $a(t)$. It is shown that the photon non-null mass does not alter significantly the result $a\\propto t^{1/2}$ valid for a massless photon gas; this is true either in Proca's case (where the photon mass $m$ is extremely small) or in Podolsky field (for which $m$ is extremely large).

  15. New information on photon fragmentation functions

    Science.gov (United States)

    Klasen, Michael; König, Florian

    2014-08-01

    Thermal photons radiated in heavy-ion collisions represent an important signal for a recently discovered new state of matter, the deconfined quark-gluon plasma. However, a clean identification of this signal requires precise knowledge of the prompt photons produced simultaneously in hard collisions of quarks and gluons, mostly through their fragmentation. In this paper, we demonstrate that PHENIX data on photons produced in proton-proton collisions with low transverse momenta allow to extract new information on this fragmentation process. While existing data do not yet convincingly favor one parameterization (BFG II) over the two other frequently used photon fragmentation functions (BFG I and GRV NLO), the data sets recorded by PHENIX and STAR at BNL RHIC in 2013 with tenfold higher statistics should allow for such an analysis.

  16. New information on photon fragmentation functions

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, Michael; Koenig, Florian [Westfaelische Wilhelms-Universitaet Muenster, Institut fuer Theoretische Physik, Muenster (Germany)

    2014-08-15

    Thermal photons radiated in heavy-ion collisions represent an important signal for a recently discovered new state of matter, the deconfined quark-gluon plasma. However, a clean identification of this signal requires precise knowledge of the prompt photons produced simultaneously in hard collisions of quarks and gluons, mostly through their fragmentation. In this paper, we demonstrate that PHENIX data on photons produced in proton-proton collisions with low transverse momenta allow one to extract new information on this fragmentation process. While existing data do not yet convincingly favor one parameterization (BFG II) over the two other frequently used photon fragmentation functions (BFG I and GRV NLO), the data sets recorded by PHENIX and STAR at BNL RHIC in 2013 with tenfold higher statistics should allow for such an analysis. (orig.)

  17. All Photons Imaging Through Volumetric Scattering

    Science.gov (United States)

    Satat, Guy; Heshmat, Barmak; Raviv, Dan; Raskar, Ramesh

    2016-01-01

    Imaging through thick highly scattering media (sample thickness ≫ mean free path) can realize broad applications in biomedical and industrial imaging as well as remote sensing. Here we propose a computational “All Photons Imaging” (API) framework that utilizes time-resolved measurement for imaging through thick volumetric scattering by using both early arrived (non-scattered) and diffused photons. As opposed to other methods which aim to lock on specific photons (coherent, ballistic, acoustically modulated, etc.), this framework aims to use all of the optical signal. Compared to conventional early photon measurements for imaging through a 15 mm tissue phantom, our method shows a two fold improvement in spatial resolution (4db increase in Peak SNR). This all optical, calibration-free framework enables widefield imaging through thick turbid media, and opens new avenues in non-invasive testing, analysis, and diagnosis. PMID:27683065

  18. Entangled Photons from Radiative Cascades in Semiconductor Quantum Dots

    CERN Document Server

    Akopian, N; Poem, E; Berlatzky, Y; Avron, J; Gershoni, D; Gerardot, B D; Petroff, P M

    2005-01-01

    We show, for the first time, that polarization-entangled photon pairs can be produced from the biexciton radiative cascade in a semiconductor quantum dot. We select an energy window that erases the ``which path'' information contained in the colors of the emitted photons, and use tomographic analysis to demonstrate that the photon pair violate Bell's inequality and satisfy Peres criterion for entanglement by more than 3 standard deviations of the experimental uncertainty. Our quantitative analysis show that semiconductor quantum dots can be used as sources for ``event-ready'' entangled photons.

  19. Prompt photon production in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Krzysztof

    2010-03-15

    This thesis presents measurement of the production of prompt photons in photoproduction with the H1 experiment at HERA. The analysis is based on the data taken in the years 2004-2007, with a total integrated luminosity of 340 pb{sup -1}. The main difficulty of the measurement comes from the high background of neutral mesons decaying into photons. It is accounted for with the help of multivariate analysis. Prompt photon cross sections are measured with the low negative four-momentum transfer squared Q{sup 2} < 1GeV{sup 2} and in the inelasticity range 0.1 < y < 0.7 for photons with a transverse energy 6 < E{sub T}{sup {gamma}} < 15GeV and in the pseudorapidity range.1.0 < {eta}{sup {gamma}} < 2.4 as a function of photons transverse energy and its pseudorapidity. Cross sections for prompt photon events with an additional hadronic jet are measured as a function of the transverse energy and pseudorapidity of the jet and of the momentum fractions x{sub {gamma}} and x{sub p} of the incident photon and proton carried by the constituents participating in the hard scattering process. Additionally, the transverse correlation between the photon and the jet is studied. The results are compared with predictions of a next-to-leading order calculation and a calculation based on the k{sub T} factorisation approach. Neither of calculations is able to describe all the aspects of the measurement. (orig.)

  20. Cytotoxic activity and phytochemical analysis of Arum palaestinum Boiss

    Institute of Scientific and Technical Information of China (English)

    Mai Mohammed Farid; Sameh Reda Hussein; Lamiaa Fawzy Ibrahim; Mohammed Ali El Desouky; Amr Mohammed Elsayed; Ahmad Ali El Oqlah; Mahmoud Mohammed Saker

    2015-01-01

    Objective:To evaluate the in vitro cytotoxic activity of the fractionated extract as well as isolated compounds of Arum palaestinum Boiss. (A. palaestinum) (black calla lily), and to identify the volatile components which may be responsible for the potential antitumor activity. Methods: A. palaestinum was collected from its natural habitats and subjected to phytochemical analysis for separation of pure compounds. In vitro cytotoxic activity was investigated against four human carcinoma cell lines Hep2, HeLa, HepG2 and MCF7 for the fractionated extract and isolated compounds. While, the diethyl ether fraction was subjected to GC–MS analysis as it exhibited the most potent cytotoxic effect to evaluate the active constituents responsible for the cytotoxic activities. Results:Four flavonoid compounds were isolated (luteolin, chrysoeriol, isoorientin, isovitexin) from the diethyl ether and ethyl acetate. The extracts and the pure isolated compounds showed a significant high antiproliferative activity against all investigated cell lines. The GC–MS analysis revealed the separation and identification of 15 compounds representing 95.01%of the extract and belonging to different groups of chemical compounds. Conclusions:The present study is considered to be the first report on the cytotoxic activities carried out on different selected fractions and pure compounds of A. palaestinum to provide evidences for its strong antitumor activities. In addition, chrysoeriol and isovitexin compounds were isolated for the first time from the studied taxa.

  1. Cytotoxic activity and phytochemical analysis of Arum palaestinum Boiss.

    Institute of Scientific and Technical Information of China (English)

    Mai; Mohammed; Farid; Sameh; Reda; Hussein; Lamiaa; Fawzy; Ibrahim; Mohammed; Ali; El; Desouky; Amr; Mohammed; Elsayed; Ahmad; Ali; El; Oqlah; Mahmoud; Mohammed; Saker

    2015-01-01

    Objective: To evaluate the in vitro cytotoxic activity of the fractionated extract as well as isolated compounds of Arum palaestinum Boiss.(A. palaestinum)(black calla lily), and to identify the volatile components which may be responsible for the potential antitumor activity.Methods: A. palaestinum was collected from its natural habitats and subjected to phytochemical analysis for separation of pure compounds. In vitro cytotoxic activity was investigated against four human carcinoma cell lines Hep2, He La, Hep G2 and MCF7 for the fractionated extract and isolated compounds. While, the diethyl ether fraction was subjected to GC–MS analysis as it exhibited the most potent cytotoxic effect to evaluate the active constituents responsible for the cytotoxic activities.Results: Four flavonoid compounds were isolated(luteolin, chrysoeriol, isoorientin,isovitexin) from the diethyl ether and ethyl acetate. The extracts and the pure isolated compounds showed a significant high antiproliferative activity against all investigated cell lines. The GC–MS analysis revealed the separation and identification of 15 compounds representing 95.01% of the extract and belonging to different groups of chemical compounds.Conclusions: The present study is considered to be the first report on the cytotoxic activities carried out on different selected fractions and pure compounds of A. palaestinum to provide evidences for its strong antitumor activities. In addition,chrysoeriol and isovitexin compounds were isolated for the first time from the studied taxa.

  2. Tomography of photon-added and photon-subtracted states

    NARCIS (Netherlands)

    Bazrafkan, MR; Man'ko, [No Value

    2003-01-01

    The purpose of this paper is to introduce symplectic and optical tomograms of photon-added and photon-subtracted quantum states. Explicit relations for the tomograms of photon-added and photon-subtracted squeezed coherent states and squeezed number states are obtained. Generating functions for the m

  3. Fundamentals of microwave photonics

    CERN Document Server

    Urick, V J; McKinney , Jason D

    2015-01-01

    A comprehensive resource to designing andconstructing analog photonic links capable of high RFperformanceFundamentals of Microwave Photonics provides acomprehensive description of analog optical links from basicprinciples to applications.  The book is organized into fourparts. The first begins with a historical perspective of microwavephotonics, listing the advantages of fiber optic links anddelineating analog vs. digital links. The second section coversbasic principles associated with microwave photonics in both the RFand optical domains.  The third focuses on analog modulationformats-starti

  4. Physics of photonic devices

    CERN Document Server

    Chuang, Shun Lien

    2009-01-01

    The most up-to-date book available on the physics of photonic devices This new edition of Physics of Photonic Devices incorporates significant advancements in the field of photonics that have occurred since publication of the first edition (Physics of Optoelectronic Devices). New topics covered include a brief history of the invention of semiconductor lasers, the Lorentz dipole method and metal plasmas, matrix optics, surface plasma waveguides, optical ring resonators, integrated electroabsorption modulator-lasers, and solar cells. It also introduces exciting new fields of research such as:

  5. Photon collider Higgs factories

    CERN Document Server

    Telnov, V I

    2014-01-01

    The discovery of the Higgs boson (and still nothing else) have triggered appearance of many proposals of Higgs factories for precision measurement of the Higgs properties. Among them there are several projects of photon colliders (PC) without e+e- in addition to PLC based on e+e- linear colliders ILC and CLIC. In this paper, following a brief discussion of Higgs factories physics program I give an overview of photon colliders based on linear colliders ILC and CLIC, and of the recently proposed photon-collider Higgs factories with no e+e- collision option based on recirculation linacs in ring tunnels.

  6. Single photon quantum cryptography.

    Science.gov (United States)

    Beveratos, Alexios; Brouri, Rosa; Gacoin, Thierry; Villing, André; Poizat, Jean-Philippe; Grangier, Philippe

    2002-10-28

    We report the full implementation of a quantum cryptography protocol using a stream of single photon pulses generated by a stable and efficient source operating at room temperature. The single photon pulses are emitted on demand by a single nitrogen-vacancy color center in a diamond nanocrystal. The quantum bit error rate is less that 4.6% and the secure bit rate is 7700 bits/s. The overall performances of our system reaches a domain where single photons have a measurable advantage over an equivalent system based on attenuated light pulses.

  7. Photonics: Technology project summary

    Science.gov (United States)

    Depaula, Ramon P.

    1991-01-01

    Photonics involves the use of light (photons) in conjunction with electronics for applications in communications, computing, control, and sensing. Components used in photonic systems include lasers, optical detectors, optical wave guide devices, fiber optics, and traditional electronic devices. The goal of this program is to develop hybrid optoelectronic devices and systems for sensing, information processing, communications, and control. It is hoped that these new devices will yield at least an order of magnitude improvement in performance over existing technology. The objective of the program is to conduct research and development in the following areas: (1) materials and devices; (2) networking and computing; (3) optical processing/advanced pattern recognition; and (4) sensing.

  8. Bi-directional evolutionary optimization for photonic band gap structures

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Fei [Centre for Innovative Structures and Materials, School of Civil, Environmental and Chemical Engineering, RMIT University, GPO Box 2476, Melbourne, VIC 3001 (Australia); School of Civil Engineering, Central South University, Changsha 410075 (China); Huang, Xiaodong, E-mail: huang.xiaodong@rmit.edu.au [Centre for Innovative Structures and Materials, School of Civil, Environmental and Chemical Engineering, RMIT University, GPO Box 2476, Melbourne, VIC 3001 (Australia); Key Laboratory of Advanced Technology for Vehicle Body Design & Manufacture, Hunan University, Changsha, 410082 (China); Jia, Baohua [Centre for Micro-Photonics, Faculty of Engineering & Industrial Science, Swinburne University of Technology, PO Box 218, Hawthorn, VIC 3122 (Australia)

    2015-12-01

    Toward an efficient and easy-implement optimization for photonic band gap structures, this paper extends the bi-directional evolutionary structural optimization (BESO) method for maximizing photonic band gaps. Photonic crystals are assumed to be periodically composed of two dielectric materials with the different permittivity. Based on the finite element analysis and sensitivity analysis, BESO starts from a simple initial design without any band gap and gradually re-distributes dielectric materials within the unit cell so that the resulting photonic crystal possesses a maximum band gap between two specified adjacent bands. Numerical examples demonstrated the proposed optimization algorithm can successfully obtain the band gaps from the first to the tenth band for both transverse magnetic and electric polarizations. Some optimized photonic crystals exhibit novel patterns markedly different from traditional designs of photonic crystals.

  9. Effect of polarization entanglement in photon-photon scattering

    Science.gov (United States)

    Rätzel, Dennis; Wilkens, Martin; Menzel, Ralf

    2017-01-01

    It is found that the differential cross section of photon-photon scattering is a function of the degree of polarization entanglement of the two-photon state. A reduced general expression for the differential cross section of photon-photon scattering is derived by applying simple symmetry arguments. An explicit expression is obtained for the example of photon-photon scattering due to virtual electron-positron pairs in quantum electrodynamics. It is shown how the effect in this explicit example can be explained as an effect of quantum interference and that it fits with the idea of distance-dependent forces.

  10. MULTI-PHOTON PHOSPHOR FEASIBILITY RESEARCH

    Energy Technology Data Exchange (ETDEWEB)

    R. Graham; W. Chow

    2003-05-01

    Development of multi-photon phosphor materials for discharge lamps represents a goal that would achieve up to a doubling of discharge (fluorescent) lamp efficacy. This report reviews the existing literature on multi-photon phosphors, identifies obstacles in developing such phosphors, and recommends directions for future research to address these obstacles. To critically examine issues involved in developing a multi-photon phosphor, the project brought together a team of experts from universities, national laboratories, and an industrial lamp manufacturer. Results and findings are organized into three categories: (1) Multi-Photon Systems and Processes, (2) Chemistry and Materials Issues, and (3) Concepts and Models. Multi-Photon Systems and Processes: This category focuses on how to use our current understanding of multi-photon phosphor systems to design new phosphor systems for application in fluorescent lamps. The quickest way to develop multi-photon lamp phosphors lies in finding sensitizer ions for Gd{sup 3+} and identifying activator ions to red shift the blue emission from Pr{sup 3+} due to the {sup 1}S{sub 0} {yields} {sup 1}I{sub 6} transition associated with the first cascading step. Success in either of these developments would lead to more efficient fluorescent lamps. Chemistry and Materials Issues: The most promising multi-photon phosphors are found in fluoride hosts. However, stability of fluorides in environments typically found in fluorescent lamps needs to be greatly improved. Experimental investigation of fluorides in actual lamp environments needs to be undertaken while working on oxide and oxyfluoride alternative systems for backup. Concepts and Models: Successful design of a multi-photon phosphor system based on cascading transitions of Gd{sup 3+} and Pr{sup 3+} depends critically on how the former can be sensitized and the latter can sensitize an activator ion. Methods to predict energy level diagrams and Judd-Ofelt parameters of multi-photon

  11. Microwave background constraints on mixing of photons with hidden photons

    Energy Technology Data Exchange (ETDEWEB)

    Mirizzi, Alessandro [Max-Planck-Institut fuer Physik, Muenchen (Germany); Redondo, Javier [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Sigl, Guenter [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2008-12-15

    Various extensions of the Standard Model predict the existence of hidden photons kinetically mixing with the ordinary photon. This mixing leads to oscillations between photons and hidden photons, analogous to the observed oscillations between different neutrino flavors. In this context, we derive new bounds on the photon-hidden photon mixing parameters using the high precision cosmic microwave background spectral data collected by the Far Infrared Absolute Spectrophotometer instrument on board of the Cosmic Background Explorer. Requiring the distortions of the CMB induced by the photon-hidden photon mixing to be smaller than experimental upper limits, this leads to a bound on the mixing angle {chi}{sub 0}

  12. Coupled multi-group neutron photon transport for the simulation of high-resolution gamma-ray spectroscopy applications

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Kimberly A. [Georgia Inst. of Technology, Atlanta, GA (United States)

    2009-08-01

    The accurate and efficient simulation of coupled neutron-photon problems is necessary for several important radiation detection applications. Examples include the detection of nuclear threats concealed in cargo containers and prompt gamma neutron activation analysis for nondestructive determination of elemental composition of unknown samples.

  13. Efficient single photon emission from a high-purity hexagonal boron nitride crystal

    Science.gov (United States)

    Martínez, L. J.; Pelini, T.; Waselowski, V.; Maze, J. R.; Gil, B.; Cassabois, G.; Jacques, V.

    2016-09-01

    Among a variety of layered materials used as building blocks in van der Waals heterostructures, hexagonal boron nitride (hBN) appears as an ideal platform for hosting optically active defects owing to its large band gap (˜6 eV ). Here we study the optical response of a high-purity hBN crystal under green laser illumination. By means of photon correlation measurements, we identify individual defects emitting a highly photostable fluorescence under ambient conditions. A detailed analysis of the photophysical properties reveals a high quantum efficiency of the radiative transition, leading to a single photon source with very high brightness (˜4 ×106 counts s-1). These results illustrate how the wide range of applications offered by hBN could be further extended to photonic-based quantum information science and metrology.

  14. Behavioral activation treatments of depression: a meta-analysis.

    Science.gov (United States)

    Cuijpers, Pim; van Straten, Annemieke; Warmerdam, Lisanne

    2007-04-01

    Activity scheduling is a behavioral treatment of depression in which patients learn to monitor their mood and daily activities, and how to increase the number of pleasant activities and to increase positive interactions with their environment. We conducted a meta-analysis of randomized effect studies of activity scheduling. Sixteen studies with 780 subjects were included. The pooled effect size indicating the difference between intervention and control conditions at post-test was 0.87 (95% CI: 0.60 - 1.15). This is a large effect. Heterogeneity was low in all analyses. The comparisons with other psychological treatments at post-test resulted in a non-significant pooled effect size of 0.13 in favor of activity scheduling. In ten studies activity scheduling was compared to cognitive therapy, and the pooled effect size indicating the difference between these two types of treatment was 0.02. The changes from post-test to follow-up for activity scheduling were non-significant, indicating that the benefits of the treatments were retained at follow-up. The differences between activity scheduling and cognitive therapy at follow-up were also non-significant. Activity scheduling is an attractive treatment for depression, not only because it is relatively uncomplicated, time-efficient and does not require complex skills from patients or therapist, but also because this meta-analysis found clear indications that it is effective.

  15. Photonics in switching: enabling technologies and subsystem design

    DEFF Research Database (Denmark)

    Vlachos, K.; Raffaelli, C.; Aleksic, S.

    2009-01-01

    This paper describes recent research activities and results in the area of photonic switching carried out within the framework of the EU-funded e-Photon/ONe + network of excellence, Virtual Department on Optical Switching. Technology aspects of photonics in switching and, in particular, recent ad...... advances in wavelength conversion, ring resonators, and packet switching and processing subsystems are presented as the building blocks for the implementation of a high-performance router for the next-generation Internet....

  16. Recent results in silicon photonics at the University of Southampton

    Science.gov (United States)

    Reed, G. T.; Mashanovich, G. Z.; Gardes, F. Y.; Thomson, D. J.; Hu, Y.; Soler-Penades, J.; Nedeljkovic, M.; Khokhar, A. Z.; Thomas, P.; Littlejohns, C.; Ahmad, A.; Reynolds, S.; Topley, R.; Mitchell, C.; Stankovic, S.; Owens, N.; Chen, X.; Wilson, P. R.; Ke, L.; Ben Masaud, T. M.; Tarazona, A.; Chong, H.

    2014-03-01

    In this paper we will discuss recent results in our work on Silicon Photonics. This will include active and passive devices for a range of applications. Specifically we will include work on modulators and drivers, deposited waveguides, multiplexers, device integration and Mid IR silicon photonics. These devices and technologies are important both for established applications such as integrated transceivers for short reach interconnect, as well as emerging applications such as disposable sensors and mass market photonics.

  17. Design of Tunable Anisotropic Photonic Crystal Filter as Photonic Switch

    OpenAIRE

    Majid Seifan; Alireza Malekijavan; Alireza Monajati Kashani

    2014-01-01

    By creating point defects and line defects in photonic crystals, we reach the new sort of photonic crystals. Which allow us to design photonic crystals filters. In this type of photonic crystals the ability to tune up central frequency of filter is important to attention. In this paper, we use foregoing points for designing photonic crystal filters. The main function of this type of filters is coupling between shield of point defect modes and directional line defect modes. By using liquid cry...

  18. Photon Polarization in Photonic Crystal Fibers under Compton Scattering

    Institute of Scientific and Technical Information of China (English)

    HAO Dong-shan; ZHANG Xiao-fu

    2007-01-01

    Using the quantum invariant theory and unitary transformation means, we study the influences of multi-photon nonlinear Compton scattering on the photon polarization in photonic crystal fibers(PCF). The results show that the photon polarization of the incident photon changes a lot due to scattered optical, and its general geometric phase factor, Hamiton number and evolution operator are definited both by the incident and scattered optical.

  19. Nanomanipulation using near field photonics.

    Science.gov (United States)

    Erickson, David; Serey, Xavier; Chen, Yih-Fan; Mandal, Sudeep

    2011-03-21

    In this article we review the use of near-field photonics for trapping, transport and handling of nanomaterials. While the advantages of traditional optical tweezing are well known at the microscale, direct application of these techniques to the handling of nanoscale materials has proven difficult due to unfavourable scaling of the fundamental physics. Recently a number of research groups have demonstrated how the evanescent fields surrounding photonic structures like photonic waveguides, optical resonators, and plasmonic nanoparticles can be used to greatly enhance optical forces. Here, we introduce some of the most common implementations of these techniques, focusing on those which have relevance to microfluidic or optofluidic applications. Since the field is still relatively nascent, we spend much of the article laying out the fundamental and practical advantages that near field optical manipulation offers over both traditional optical tweezing and other particle handling techniques. In addition we highlight three application areas where these techniques namely could be of interest to the lab-on-a-chip community, namely: single molecule analysis, nanoassembly, and optical chromatography.

  20. A grid for a precise analysis of daily activities.

    Science.gov (United States)

    Wojtasik, V; Olivier, C; Lekeu, F; Quittre, A; Adam, S; Salmon, E

    2010-01-01

    Assessment of daily living activities is essential in patients with Alzheimer's disease. Most current tools quantitatively assess overall ability but provide little qualitative information on individual difficulties. Only a few tools allow therapists to evaluate stereotyped activities and record different types of errors. We capitalised on the Kitchen Activity Assessment to design a widely applicable analysis grid that provides both qualitative and quantitative data on activity performance. A cooking activity was videotaped in 15 patients with dementia and assessed according to the different steps in the execution of the task. The evaluations obtained with our grid showed good correlations between raters, between versions of the grid and between sessions. Moreover, the degree of independence obtained with our analysis of the task correlated with the Kitchen Activity Assessment score and with a global score of cognitive functioning. We conclude that assessment of a daily living activity with this analysis grid is reproducible and relatively independent of the therapist, and thus provides quantitative and qualitative information useful for both evaluating and caring for demented patients.

  1. What is a photon?

    CERN Document Server

    Natarajan, Vasant

    2013-01-01

    We discuss the absorber theory of radiation as put forward by Wheeler and Feynman. We show that it gives a better understanding of the photon compared to the usual quantum electrodynamics (QED) picture.

  2. Nonlinear optics and photonics

    CERN Document Server

    He, Guang S

    2015-01-01

    This book provides a comprehensive presentation on most of the major topics in nonlinear optics and photonics, with equal emphasis on principles, experiments, techniques, and applications. It covers many major new topics including optical solitons, multi-photon effects, nonlinear photoelectric effects, fast and slow light , and Terahertz photonics. Chapters 1-10 present the fundamentals of modern nonlinear optics, and could be used as a textbook with problems provided at the end of each chapter. Chapters 11-17 cover the more advanced topics of techniques and applications of nonlinear optics and photonics, serving as a highly informative reference for researchers and experts working in related areas. There are also 16 pages of color photographs to illustrate the visual appearances of some typical nonlinear optical effects and phenomena. The book could be adopted as a textbook for both undergraduates and graduate students, and serve as a useful reference work for researchers and experts in the fields of physics...

  3. Principles of photonics

    CERN Document Server

    Liu, Jia-Ming

    2016-01-01

    With this self-contained and comprehensive text, students will gain a detailed understanding of the fundamental concepts and major principles of photonics. Assuming only a basic background in optics, readers are guided through key topics such as the nature of optical fields, the properties of optical materials, and the principles of major photonic functions regarding the generation, propagation, coupling, interference, amplification, modulation, and detection of optical waves or signals. Numerous examples and problems are provided throughout to enhance understanding, and a solutions manual containing detailed solutions and explanations is available online for instructors. This is the ideal resource for electrical engineering and physics undergraduates taking introductory, single-semester or single-quarter courses in photonics, providing them with the knowledge and skills needed to progress to more advanced courses on photonic devices, systems and applications.

  4. LightForce Photon-pressure Collision Avoidance: Efficiency Analysis in the Current Debris Environment and Long-Term Simulation Perspective

    Science.gov (United States)

    Yang, Fan Y.; Nelson, Bron; Carlino, Roberto; Perez, Andres D.; Faber, Nicolas; Henze, Chris; Karacahoglu, Arif G.; O'Toole, Conor; Swenson, Jason; Stupl, Jan

    2015-01-01

    This work provides an efficiency analysis of the LightForce space debris collision avoidance scheme in the current debris environment and describes a simulation approach to assess its impact on the long-term evolution of the space debris environment. LightForce aims to provide just-in-time collision avoidance by utilizing photon pressure from ground-based industrial lasers. These ground stations impart minimal accelerations to increase the miss distance for a predicted conjunction between two objects. In the first part of this paper we will present research that investigates the short-term effect of a few systems consisting of 10kW class lasers directed by 1.5 m diameter telescopes using adaptive optics. The results found such a network of ground stations to mitigate more than 85 percent of conjunctions and could lower the expected number of collisions in Low Earth Orbit (LEO) by an order of magnitude. While these are impressive numbers that indicate LightForce's utility in the short-term, the remaining 15 percent of possible collisions contain (among others) conjunctions between two massive objects that would add large amount of debris if they collide. Still, conjunctions between massive objects and smaller objects can be mitigated. Hence we choose to expand the capabilities of the simulation software to investigate the overall effect of a network of LightForce stations on the long-term debris evolution. In the second part of this paper, we will present the planed simulation approach for that effort.

  5. Description of the states of two-photon interference in an optical gating Michelson interferometer

    Science.gov (United States)

    Pongophas, Ekkarat; Sriklin, Watthana; Sinsarp, Asawin; Suwanna, Sujin; Chunwachirasiri, Withoon; Singhsomroje, Wisit

    2016-01-01

    We investigate the interference of two photons in an optical gating Michelson interferometer. The phenomenon is studied using two different representations of photons: the space-time domain and a step-by-step two-photon state evolution. Both representations lead to identical results. The evolution analysis describes the result by the interference of four two-photon traveling states, whereas the space-time domain analysis reveals that the classical interference of the high-intensity light source is identical to two-photon interference in the quantum regime, except for a multiplicative factor of (n2), where n is the number of photons.

  6. Photonic bandgap structures

    CERN Document Server

    Marco, Pisco; Antonello, Cutolo

    2012-01-01

    This E-Book covers the research and the development of a novel generation of photonic devices for sensing applications. Key features of this book include a brief review of basic PhCs related design and fabrication concepts, a selection of crossover topics for the development of novel technological platforms for physical, chemical and biological sensing and a description of the main PhCs sensors to date by representing many of the exciting sensing applications that utilize photonic crystal structures.

  7. Photonics in switching

    CERN Document Server

    Midwinter, John E; Kelley, Paul

    1993-01-01

    Photonics in Switching provides a broad, balanced overview of the use of optics or photonics in switching, from materials and devices to system architecture. The chapters, each written by an expert in the field, survey the key technologies, setting them in context and highlighting their benefits and possible applications. This book is a valuable resource for those working in the communications industry, either at the professional or student level, who do not have extensive background knowledge or the underlying physics of the technology.

  8. Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Barkou, Stig Eigil; Broeng, Jes; Bjarklev, Anders Overgaard

    1999-01-01

    Photonic bandgap fibers are describes using a new Kagomé cladding structure. These fibers may potentially guide light in low-index regions. Such fibers offer new dispersion properties, and large design flexibility.......Photonic bandgap fibers are describes using a new Kagomé cladding structure. These fibers may potentially guide light in low-index regions. Such fibers offer new dispersion properties, and large design flexibility....

  9. ALICE photon spectrometer crystals

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    Members of the mechanical assembly team insert the last few crystals into the first module of ALICE's photon spectrometer. These crystals are made from lead-tungstate, a crystal as clear as glass but with nearly four times the density. When a high-energy particle passes through one of these crystals it will scintillate, emitting a flash of light allowing the energy of photons, electrons and positrons to be measured.

  10. Ultrastable Multigigahertz Photonic Oscillator

    Science.gov (United States)

    Logan, Ronald T., Jr.

    1996-01-01

    Novel photonic oscillator developed to serve as ultrastable source of microwave and millimeter-wave signals. In system, oscillations generated photonically, then converted to electronic form. Includes self-mode-locked semiconductor laser producing stream of pulses, detected and fed back to laser as input. System also includes fiber-optic-delay-line discriminator, which detects fluctuations of self-mode-locking frequency and generates error signal used in negative-feedback loop to stabilize pulse-repetition frequency.

  11. QUANTUM CRYPTOGRAPHY: Single Photons.

    Science.gov (United States)

    Benjamin, S

    2000-12-22

    Quantum cryptography offers the potential of totally secure transfer of information, but as Benjamin discusses in this Perspective, its practical implementation hinges on being able to generate single photons (rather than two or more) at a time. Michler et al. show how this condition can be met in a quantum dot microdisk structure. Single molecules were also recently shown to allow controlled single-photon emission.

  12. A package for gamma-ray spectrum analysis and routine neutron activation analysis

    Indian Academy of Sciences (India)

    M E Medhat; A Abdel-Hafiez; Z Awaad; M A Ali

    2005-08-01

    A package for gamma spectrum analysis (PGSA) was developed using object oriented Borland C++ design for MS-windows. This package consists of five programs which can be used for gamma-ray spectrum analysis and routine neutron activation analysis. The advantages of PGSA are its simple algorithms and its need for only minimum amount of input information.

  13. Analysis of nuclear activity of ten polar ring galaxies

    CERN Document Server

    Freitas-Lemes, P; Dors, O L; Faúndez-Abans, M

    2013-01-01

    The accumulation of mass from the interaction process that forms the polar ring galaxies is a factor that favors the conditions necessary to trigger nonthermal nuclear activities.. This fact encouraged the chemical analysis of ten polar ring galaxies. In order to verify the presence of an active nucleus in these galaxias, we built diagnostic diagrams using lines H{\\beta}, [OIII], [HI], H{\\alpha}, [NII], and [SII] and classified the type of nuclear activity. For galaxies that do not show shock, the parameters N2 and O3N2 were also determined. From this sample, we identified seven galaxies with an active nucleus and three that behave as HII regions. One galaxy with an active nucleus was classified as Seyfert. Although our data do not provide a statistically significant sample, we can speculate that polar ring galaxies are a setting conducive to trigger non-thermal nuclear activities.

  14. Performance Analysis for Dispensing Mechanism of Active Code

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The dispensing mechanism of active code is a key technology in an active network. Conventional capsule and programmable switch approaches have their own shortcomings. The DCCAN(distributed code caching for active network) mechanism presented in this paper overcomes these shortcomings. In this paper, capsule and programmable switch approaches are introduced, and their shortcomings are analyzed. The principle of the DCCAN mechanism is described. The theory analysis in transmit width based on the DCCAN mechanism and capsule approach are described. The theory analysis shows that the DCCAN mechanism has many good characteristics and can improve the efficiency of an active network. Key factors which affect the transmit width based on the DCCAN mechanism are discussed. The using condition of the DCCAN mechanism is also discussed.

  15. Photon activated therapy (PAT using monochromatic Synchrotron x-rays and iron oxide nanoparticles in a mouse tumor model: feasibility study of PAT for the treatment of superficial malignancy

    Directory of Open Access Journals (Sweden)

    Choi Gi-Hwan

    2012-10-01

    Full Text Available Abstract Background X-rays are known to interact with metallic nanoparticles, producing photoelectric species as radiosensitizing effects, and have been exploited in vivo mainly with gold nanoparticles. The purpose of this study was to investigate the potential of sensitizing effect of iron oxide nanoparticles for photon activated therapy. Methods X-rays photon activated therapy (PAT was studied by treating CT26 tumor cells and CT26 tumor-bearing mice loaded with 13-nm diameter FeO NP, and irradiating them at 7.1 keV near the Fe K-edge using synchrotron x-rays radiation. Survival of cells was determined by MTT assay, and tumor regression assay was performed for in vivo model experiment. The results of PAT treated groups were compared with x-rays alone control groups. Results A more significant reduction in viability and damage was observed in the FeO NP-treated irradiated cells, compared to the radiation alone group (p Conclusions An iron oxide nanoparticle enhanced therapeutic effect with relatively low tissue concentration of iron and 10 Gy of monochromatic X-rays. Since 7.1 keV X-rays is attenuated very sharply in the tissue, FeO NP-PAT may have promise as a potent treatment option for superficial malignancies in the skin, like chest wall recurrence of breast cancer.

  16. Design of photonic crystal splitters/combiners

    Science.gov (United States)

    Kim, Sangin; Park, Ikmo; Lim, Hanjo

    2004-10-01

    Photonic band gap (PBG) structures or photonic crystals have attracted a lot of interest since one of their promising applications is to build compact photonic integrated circuits (PIC). One of key components in PICs is a 1 x 2 optical power splitter or a 2 x 1 combiner. Design of 1 x 2 optical power splitters based on photonic crystal has been investigated by several research groups, but no attention has been paid to the design of 2 x 1 optical combiners. In conventional dielectric waveguide based circuits, optical combiners are obtained just by operating the splitters in the opposite direction and the isolation between two input ports in the combiners is naturally achieved. In photonic crystal based circuits, however, we have found that reciprocal operation of the splitters as combiners will not provide proper isolation between the input ports of the combiners. In this work, microwave-circuit concept has been adopted to obtain isolation between two input ports of the combiner and compact optical power splitters/combiners of good performance have been designed using 2-D photonic crystal. Numerical analysis of the designed splitters/combiners has been performed with the finite-difference time-domain method. The designed splitters/combiners show good isolation between input ports in combiner operation with small return losses.

  17. INDUSTRIAL/MILITARY ACTIVITY-INITIATED ACCIDENT SCREENING ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    D.A. Kalinich

    1999-09-27

    Impacts due to nearby installations and operations were determined in the Preliminary MGDS Hazards Analysis (CRWMS M&O 1996) to be potentially applicable to the proposed repository at Yucca Mountain. This determination was conservatively based on limited knowledge of the potential activities ongoing on or off the Nevada Test Site (NTS). It is intended that the Industrial/Military Activity-Initiated Accident Screening Analysis provided herein will meet the requirements of the ''Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants'' (NRC 1987) in establishing whether this external event can be screened from further consideration or must be included as a design basis event (DBE) in the development of accident scenarios for the Monitored Geologic Repository (MGR). This analysis only considers issues related to preclosure radiological safety. Issues important to waste isolation as related to impact from nearby installations will be covered in the MGR performance assessment.

  18. Visual Analysis of Biological Activity Data with Scaffold Hunter.

    Science.gov (United States)

    Klein, Karsten; Koch, Oliver; Kriege, Nils; Mutzel, Petra; Schäfer, Till

    2013-12-01

    The growing interest in chemogenomics approaches over the last years has led to an increasing amount of data regarding chemical and the corresponding biological activity space. The resulting data, collected in either in-house or public databases, need to be analyzed efficiently to speed-up the increasingly difficult task of drug discovery. Unfortunately, the discovery of new chemical entities or new targets for known drugs ('drug repurposing') is not suitable to a fully automated analysis or a simple drill down process. Visual interactive interfaces that allow to explore chemical space in a systematic manner and facilitate analytical reasoning can help to overcome these problems. Scaffold Hunter is a tool for the visual analysis of chemical compound databases that provides integrated visualization and analysis of biological activity data and fosters the interactive exploration of data imported from a variety of sources. We describe the features and illustrate the use by means of an exemplary analysis workflow.

  19. Luminescence properties of a Fibonacci photonic quasicrystal.

    Science.gov (United States)

    Passias, V; Valappil, N V; Shi, Z; Deych, L; Lisyansky, A A; Menon, V M

    2009-04-13

    An active one-dimensional Fibonacci photonic quasi-crystal is realized via spin coating. Luminescence properties of an organic dye embedded in the quasi-crystal are studied experimentally and compared to theoretical simulations. The luminescence occurs via the pseudo-bandedge mode and follows the dispersion properties of the Fibonacci crystal. Time resolved luminescence measurement of the active structure shows faster spontaneous emission rate, indicating the effect of the large photon densities available at the bandedge due to the presence of critically localized states. The experimental results are in good agreement with the theoretical calculations for steady-state luminescence spectra.

  20. Luminescence Properties of a Fibonacci Photonic Quasicrystal

    CERN Document Server

    Passias, Vasilios; Shi, Zhou; Deych, Lev; Lisyansky, Alexander; Menon, Vinod M

    2008-01-01

    We report the realization of an active one-dimensional Fibonacci photonic quasi-crystal via spin coating. Manipulation of the luminescence properties of an organic dye embedded in the quasi-crystal is presented and compared to theoretical simulations. The luminescence occurs via the pseudo-bandedge mode and follows the dispersion properties of the Fibonacci crystal. Time resolved luminescence measurement of the active structure shows faster spontaneous emission rate, indicating the effect of the large photon densities available at the bandedge due to the presence of critically localized states. The experimental results are in excellent agreement with the theoretical calculations.