WorldWideScience

Sample records for optically stable luminescent

  1. X-ray-sensitive storage phosphors with the optically stable luminescent centres

    CERN Document Server

    Gorin, G B; Zvezdova, N P; Kochubey, D I; Sedova, Y G; Kochubey, D I; Kulipanov, G N; Lyakh, V V; Pindyurin, V F

    2000-01-01

    NaCl, KCl, KBr and LiF crystals doped by In, Tl, Ni, Pd and Ca were investigated as X-ray-sensitive materials. Influence of the way of doping of an impurity and growing of a crystal on such parameters of a material as: sensitivity to ionising radiation; radiative, optical and thermal stability of the image, obtained after an irradiation is investigated. As a result of the work, media for recording of the X-ray images are developed. These allow to reproduce the images in a mode of a photoluminescence. Spatial resolution and the dynamic range of registration of the developed materials concede to similar parameters of commercial storage luminophores like 'Image Plates' based on BaFBr : La. At the same time, as distinct from 'Image Plates', the developed radiophotoluminophores allow a long storage and multiple readout of the information recorded.

  2. Plasmon-enhanced optically stimulated luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Guidelli, E. J.; Baffa, O. [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Fisica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Ramos, A. P., E-mail: ederguidelli@gmail.com [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Quimica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

    2015-10-15

    Full text: Optically Stimulated Luminescence dosimeters (OSLD) have been largely used for personal, medical, and industrial radiation dosimetry. Developing highly sensitive and small-sized radiation detectors and dosimeters is essential for improving spatial resolution and consequently diagnosis quality and treatment efficacy in the case of applications in radiodiagnosis and radiation therapy, for instance. Conventional methods to improve the OSLD sensitivity consist of doping and co-doping the host materials with atoms of other elements, thereby increasing the amount of trapping and/or luminescent centers. Our group is researching on the use of the plasmon properties of noble metal nanoparticles to increase OSL intensity. Upon incidence of a light beam with appropriate resonant wavelengths, the oscillation of the free electrons at the nanoparticle surface originates the Localized Surface Plasmons (LSP) and the consequent plasmon resonance band. The interaction between the LSP and the surrounding luminescent material leads to new optical properties largely employed for enhancing several luminescent processes. Here we will show our results regarding the use of LSP to increase OSLD sensitivity. The interaction between the traps/luminescent centers and the plasmons depends on the distance between them, on the plasmon resonance band intensity and position, as well as on the surrounding medium. Therefore, the plasmon-enhanced luminescence is a promising tool to develop more sensitive and miniaturized OSLD. (Author)

  3. Optically stimulated luminescence dating of rock surfaces

    DEFF Research Database (Denmark)

    Sohbati, Reza

    There are many examples of rock surfaces, rock art and stone structures whose ages are of great importance to the understanding of various phenomena in geology, climatology and archaeology. Optically stimulated luminescence (OSL) dating is a well-established chronological tool that has successfully...... of rock surfaces is successfully tested by application to two different quartz-rich rock types (sandstone and quartzite). Together with the measurement of infrared stimulated luminescence (IRSL) signals as a function of depth into the surface of different granites it is clear that both OSL and IRSL can....... Based on the studies of residual luminescence as a function of depth into a rock surface discussed above, a model is developed that relates this increase in residual luminescence to the exposure time. The model is then further developed using the quartz OSL signal from buried quartzite cobbles...

  4. Optically stimulated luminescence in retrospective dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Murray, A.S.

    2002-01-01

    Since the beginning of the 1990s the exploration of optically stimulated luminescence (OSL) in retrospective accident dosimetry has driven an intensive investigation and development programme at Riso into measurement facilities and techniques. This paper reviews some of the outcomes of this progr......Since the beginning of the 1990s the exploration of optically stimulated luminescence (OSL) in retrospective accident dosimetry has driven an intensive investigation and development programme at Riso into measurement facilities and techniques. This paper reviews some of the outcomes...

  5. Thermo-optical properties of optically stimulated luminescence in feldspars

    DEFF Research Database (Denmark)

    Poolton, N.R.J.; Bøtter-Jensen, L.; Johnsen, O.

    1995-01-01

    Optically stimulated luminescence processes in feldspars are subject to competing thermal enhancement and quenching processes: this article describes the thermal enhancement effects for orthoclase, albite and plagioclase feldspars. It is demonstrated that certain lattice vibrational modes can...

  6. Optically stimulated luminescence techniques in retrospective dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Murray, A.S.

    2001-01-01

    Optically stimulated luminescence signals from natural quartz and feldspar are now used routinely in dating geological and archaeological materials. More recently they have also been employed in accident dosimetry, i.e. the retrospective assessment of doses received as a result of a nuclear...

  7. Optically stimulated luminescence dating of young sediments

    DEFF Research Database (Denmark)

    Madsen, A.T.; Murray, A.S.

    2009-01-01

    Optically stimulated luminescence (OSL) dating of young (< 1000 years) sediments is used increasingly in a wide variety of late-Holocene studies as a mean of establishing contemporary sedimentation rates or the timing of sediment deposition. This paper provides a summary of the basic principles o...

  8. Bi-stable optical actuator

    Science.gov (United States)

    Holdener, Fred R.; Boyd, Robert D.

    2000-01-01

    The present invention is a bi-stable optical actuator device that is depowered in both stable positions. A bearing is used to transfer motion and smoothly transition from one state to another. The optical actuator device may be maintained in a stable position either by gravity or a restraining device.

  9. Optically stimulated luminescence dating of rock surfaces

    DEFF Research Database (Denmark)

    Sohbati, Reza

    There are many examples of rock surfaces, rock art and stone structures whose ages are of great importance to the understanding of various phenomena in geology, climatology and archaeology. Optically stimulated luminescence (OSL) dating is a well-established chronological tool that has successfully...... determined the depositional age of a wide variety of fine-grained sediments, from several years to several hundred thousands of years. However, there is no routine OSL dating method applicable to larger clasts such as cobbles, boulders and other rock surfaces. Here the application of quartz OSL to the dating...... of rock surfaces is successfully tested by application to two different quartz-rich rock types (sandstone and quartzite). Together with the measurement of infrared stimulated luminescence (IRSL) signals as a function of depth into the surface of different granites it is clear that both OSL and IRSL can...

  10. Luminescent probes for optical in vivo imaging

    Science.gov (United States)

    Texier, Isabelle; Josserand, Veronique; Garanger, Elisabeth; Razkin, Jesus; Jin, Zhaohui; Dumy, Pascal; Favrot, Marie; Boturyn, Didier; Coll, Jean-Luc

    2005-04-01

    Going along with instrumental development for small animal fluorescence in vivo imaging, we are developing molecular fluorescent probes, especially for tumor targeting. Several criteria have to be taken into account for the optimization of the luminescent label. It should be adapted to the in vivo imaging optical conditions : red-shifted absorption and emission, limited overlap between absorption and emission for a good signal filtering, optimized luminescence quantum yield, limited photo-bleaching. Moreover, the whole probe should fulfill the biological requirements for in vivo labeling : adapted blood-time circulation, biological conditions compatibility, low toxicity. We here demonstrate the ability of the imaging fluorescence set-up developed in LETI to image the bio-distribution of molecular probes on short times after injection. Targeting with Cy5 labeled holo-transferrin of subcutaneous TS/Apc (angiogenic murine breast carcinoma model) or IGROV1 (human ovarian cancer) tumors was achieved. Differences in the kinetics of the protein uptake by the tumors were evidenced. IGROV1 internal metastatic nodes implanted in the peritoneal cavity could be detected in nude mice. However, targeted metastatic nodes in lung cancer could only be imaged after dissection of the mouse. These results validate our fluorescence imaging set-up and the use of Cy5 as a luminescent label. New fluorescent probes based on this dye and a molecular delivery template (the RAFT molecule) can thus be envisioned.

  11. Optically Stimulated Luminescence Fundamentals and Applications

    CERN Document Server

    McKeever, Stephen

    2011-01-01

    The book discusses advanced modern applications of optically stimulated luminescence including the appropriate fundamentals of the process. It features major chapters on the use of OSL in space radiation dosimetry, medical physics, personnel dosimetry, security, solid-state physics and other related applications. In each case, the underlying theory is discussed on an as-needed basis for a complete understanding of the phenomena, but with an emphasis of the practical applications of the technique. After an introductory chapter, Chapters 2 to 6 cover basic theory and practical aspects, personal

  12. Optically stimulated luminescence dating at Rose Cottage Cave

    CSIR Research Space (South Africa)

    Pienaar, M

    2008-01-01

    Full Text Available Six Optically stimulated luminescence (OSL) dates are compared with stratigraphically associated C-14 dates from Rose Cottage Cave. The OSL dates overlap the accepted C-14 chronology except for one sample that overestimates the expected age...

  13. Towards multi-exponential analysis in optically stimulated luminescence

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Jain, Mayank; Hansen, Per Christian

    2010-01-01

    Optically stimulated luminescence (OSL) data from quartz can follow different mathematical forms depending on the stimulation mode. These data can be described in terms of different multi-exponential models and can be numerically fitted using several well-known methods. Here we make a comparative...

  14. Electronic displays using optically pumped luminescent semiconductor nanocrystals

    Science.gov (United States)

    Weiss, Shimon; Schlamp, Michael C.; Alivisatos, A. Paul

    2011-09-27

    A multicolor electronic display is based on an array of luminescent semiconductor nanocrystals. Nanocrystals which emit light of different colors are grouped into pixels. The nanocrystals are optically pumped to produce a multicolor display. Different sized nanocrystals are used to produce the different colors. A variety of pixel addressing systems can be used.

  15. Optically stimulated luminescence dosimetry using natural and synthetic materials

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; McKeever, S.W.S.

    1996-01-01

    The application of optically stimulated luminescence (OSL) for use in radiation dosimetry is reviewed. A broad description is given of OSL techniques developed at Riso National Laboratory and at Oklahoma State University, and recent collaborative investigations on the properties of a variety...

  16. Electronic displays using optically pumped luminescent semiconductor nanocrystals

    Science.gov (United States)

    Weiss, Shimon; Schlam, Michael C; Alivisatos, A. Paul

    2014-03-25

    A multicolor electronic display is based on an array of luminescent semiconductor nanocrystals. Nanocrystals which emit tight of different colors are grouped into pixels. The nanocrystals are optically pumped to produce a multicolor display. Different sized nanocrystals are used to produce the different colors. A variety of pixel addressing systems can be used.

  17. Optically stimulated luminescence dosimetry using natural and synthetic materials

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; McKeever, S.W.S.

    1996-01-01

    The application of optically stimulated luminescence (OSL) for use in radiation dosimetry is reviewed. A broad description is given of OSL techniques developed at Riso National Laboratory and at Oklahoma State University, and recent collaborative investigations on the properties of a variety of n......, and unseparated materials such as bricks and porcelain items....

  18. Modelling of optically stimulated luminescence of zircon : assessment of the suitability for dating

    NARCIS (Netherlands)

    Turkin, A.A.; Vainshtein, D.I.; Hartog, H.W. den

    2006-01-01

    The mineral zircon, ZrSiO4, is a candidate material for optical dating because it exhibits luminescence after exposure to natural radioactivity. The kinetic model of zircon thermally stimulated luminescence proposed before has been modified and used to investigate optically Stimulated luminescence (

  19. Silica encapsulation of luminescent silicon nanoparticles: stable and biocompatible nanohybrids

    Energy Technology Data Exchange (ETDEWEB)

    Maurice, Vincent [CEA Saclay, DSM/IRAMIS/SPAM-LFP (France); Rivolta, Ilaria [University of Milano-Bicocca, Department of Experimental Medicine (DIMS) (Italy); Vincent, Julien [CEA Saclay, DSM/IRAMIS/SPAM-LFP (France); Raccurt, Olivier [CEA Grenoble, Department of Nano Materials, NanoChemistry and NanoSafety Laboratory (DRT/LITEN/DTNM/LCSN) (France); Rouzaud, Jean-Noel [Ecole Normale superieure de Paris, Laboratoire de Geologie (France); Miserrochi, Giuseppe [University of Milano-Bicocca, Department of Experimental Medicine (DIMS) (Italy); Doris, Eric [CEA, Service de Chimie Bioorganique et de Marquage, iBiTecS (France); Reynaud, Cecile; Herlin-Boime, Nathalie, E-mail: nathalie.herlin@cea.fr [CEA Saclay, DSM/IRAMIS/SPAM-LFP (France)

    2012-02-15

    This article presents a process for surface coating and functionalization of luminescent silicon nanoparticles. The particles were coated with silica using a microemulsion process that was adapted to the fragile silicon nanoparticles. The as-produced core-shell particles have a mean diameter of 35 nm and exhibit the intrinsic photoluminescence of the silicon core. The silica layer protects the core from aqueous oxidation for several days, thus allowing the use of the nanoparticles for biological applications. The nanoparticles were further coated with amines and functionalized with polyethylene glycol chains and the toxicity of the particles has been evaluated at the different stages of the process. The core-shell nanoparticles exhibit no acute toxicity towards lung cells, which is promising for further development.

  20. Thermoluminescence and optically stimulated luminescence properties of natural barytes.

    Science.gov (United States)

    Kitis, G; Kiyak, N G; Polymeris, G S

    2010-12-01

    Heavy, baryte-loaded, concrete is commonly used as radiation shielding material around high energy particle accelerators. Concrete samples received from a shielding block located at CERN cite contain many crystalline inclusions which were identified as barytes by X-ray diffraction analysis and separated by their color, classified as white, orange and green. Basic properties of thermoluminescence (TL) and optically stimulated luminescence (OSL) signals of these barytes samples such as thermal and optical stability, repeatability and mainly the linearity of both their luminescence responses were investigated as a function of beta dose. These results are also discussed regarding detailed investigation on the correlation between TL and OSL signals and their implications for retrospective dosimetry.

  1. Systematic development of new thermoluminescence and optically stimulated luminescence materials

    Energy Technology Data Exchange (ETDEWEB)

    Yukihara, E.G., E-mail: eduardo.yukihara@okstate.edu [Physics Department, 145 Physical Sciences II, Oklahoma State University, Stillwater, OK 74078 (United States); Milliken, E.D.; Oliveira, L.C. [Physics Department, 145 Physical Sciences II, Oklahoma State University, Stillwater, OK 74078 (United States); Orante-Barron, V.R. [Departamento de Investigacion en Polimeros y Materiales, Universidad de Sonora, Hermosillo, Sonora 83000, Mexico (Mexico); Jacobsohn, L.G. [Center for Optical Materials Science and Engineering Technologies (COMSET), and School of Materials Science and Engineering, Clemson University, Clemson, SC (United States); Blair, M.W. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2013-01-15

    This paper presents an overview of a systematic study to develop new thermoluminescence (TL) and optically stimulated luminescence (OSL) materials using solution combustion synthesis (SCS) for applications such as personal OSL dosimetry, 2D dose mapping, and temperature sensing. A discussion on the material requirements for these applications is included. We present X-ray diffraction (XRD) data on single phase materials obtained with SCS, as well as radioluminescence (RL), TL and OSL data of lanthanide-doped materials. The results demonstrate the possibility of producing TL and OSL materials with sensitivity similar to or approaching those of commercial TL and OSL materials used in dosimetry (e.g., LiF:Mg,Ti and Al{sub 2}O{sub 3}:C) using SCS. The results also show that the luminescence properties can be improved by Li co-doping and annealing. The presence of an atypical TL background and anomalous fading are discussed and deserve attention in future investigations. We hope that these preliminary results on the use of SCS for production of TL and OSL materials are helpful to guide future efforts towards the development of new luminescence materials for different applications. - Highlights: Black-Right-Pointing-Pointer TL and OSL material produced with sensitivity similar to commercial materials. Black-Right-Pointing-Pointer Luminescence properties improved by Li co-doping and annealing. Black-Right-Pointing-Pointer The presence of atypical TL background and anomalous fading observed.

  2. Optical ballast and adaptive dynamic stable resonator

    Institute of Scientific and Technical Information of China (English)

    Zhang Guang-Yin; Jiao Zhi-Yong; Guo Shu-Guang; Zhang Xiao-Hua; Gu Xue-Wen; Yan Cai-Fan; Wu Ding-Er; Song Feng

    2004-01-01

    In this paper a new concept of ‘optical ballast' is put forward. Optical ballast is a kind of device that can be used to decrease the variation and fluctuation of the propagation characteristics of light beams caused by the disturbance of refractive index of the medium. To illustrate the idea clearly and concretely, a fully adaptive dynamic stable solid-state laser resonator is presented as application example of optical ballast.

  3. Luminescence Instrumentation

    DEFF Research Database (Denmark)

    Jain, Mayank; Bøtter-Jensen, Lars

    2014-01-01

    This chapter gives an introduction to instrumentation for stimulated luminescence studies, with special focus on luminescence dating using the natural dosimeters, quartz and feldspars. The chapter covers basic concepts in luminescence detection, and thermal and optical stimulation, and reference...

  4. Dosimetry based on thermally and optically stimulated luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Agersnap Larsen, Niels

    1999-01-01

    Thermally Stimulated Luminescence (TL) and Optically Stimulated Luminescence (OSL) properties of quartz and {alpha}-Al{sub 2}O{sub 3} have been investigated. Anneling-induced OSL and TL sensitivity changes in quartz has been investigated by experiments and modelling. This study does not support a pre-dose effect to account for the observed annealing-induced sensitivity change. The experimental data indicates a more simple mechanism that involves alteration of the concentration of the defect centers. Results from modelling of removal or creation of defect centers comparing well with experimentally obtained data. Thermal quenching of luminescence for the main emission center, the F-center, in {alpha}-Al{sub 2}O{sub 3}:C has been investigated by analysing TL curves obtained at different heating rates. The thermal quenching dependence of luminescence is found to follow the classical Mott-Seitz expression. Basic investigations of OSL properties of {alpha}Al{sub 2}O{sub 3}:C, including: the thermal depth of the OSL traps, the temperature dependence of OSL, and the OSL stimulation spectra. Simultaneous measurements of TL and thermally stimulated conductivity (TSC) are presented for {gamma}-irradiated {alpha}Al{sub 2}O{sub 3}:C. Activation energy analysis of the data reveals a superposition of several first-order TL and TSC peaks caused by release of charge carriers from a distribution of trapping states. Furthermore a description of an experimental method developed to determine the sign of the thermally released charge carriers has been presented. (au) 8 tabs., 59 ills., 90 refs.

  5. Influence of crystal structure on the optically stimulated luminescence properties of feldspars

    DEFF Research Database (Denmark)

    Poolton, N.R.J.; Bøtter-Jensen, L.; Ypma, P.J.M.

    1994-01-01

    Work is presented showing that the crystal structure of feldspar plays an important role in determining the energy positions at which optically stimulated luminescence transitions can occur, their thermo-optical behavior, the transport properties of charge in the conduction and valence bands, and......, and the time decay characteristics of the luminescence. First-order calculations of these effects are presented, and comparison is made with experimental results.......Work is presented showing that the crystal structure of feldspar plays an important role in determining the energy positions at which optically stimulated luminescence transitions can occur, their thermo-optical behavior, the transport properties of charge in the conduction and valence bands...

  6. In vivo X-Ray excited optical luminescence from phosphor-doped aerogel and Sylgard 184 composites

    Science.gov (United States)

    Allison, Stephen W.; Baker, Ethan S.; Lynch, Kyle J.; Sabri, Firouzeh

    2017-06-01

    X-Ray excited optical luminescence (XEOL) is a new and noninvasive diagnostic technique suitable for in situ biochemical imaging and disease detection. The X-Ray excited optical luminescence of phosphor doping in crosslinked silica aerogel and Sylgard 184 hosts was investigated in this study. Composite silica aerogels and Sylgard 184 samples of 5%, 15%, and 50% concentrations by weight of La2O2S:Eu phosphor were prepared and inserted subcutaneously in a Sprague-Dawley rat and excited by X-Ray emission at 70 and 100 kV. A fiber optic bundle positioned within 5 mm of the sample collected the luminescence signal and conveyed it to a photomultiplier detector. The signal intensity scaled with dopant concentration. The time dependence of the predominantly red luminescence consisted of 60 cycle bursts of approximately 8 ms duration. The amplitude was modulated at about 10 Hz with a 60% depth. This indicates the time dependence of the X-Ray source. A simulation showed how to observe phosphor decay between individual burst pulses. The emission from the two types of composite samples was easily detected from the outside of the skin layer. Both Sylgard 184 and crosslinked silica aerogels are biocompatible and bio stable materials that could serve a variety of potential XEOL applications. These very strong signals imply potential for creating new In-vivo sensing applications and diagnostic tools.

  7. Optical characterization of luminescent silicon nanocrystals embedded in glass matrices

    Energy Technology Data Exchange (ETDEWEB)

    Debieu, Olivier

    2008-12-16

    Interstellar dust in nebulae and in the Diffuse Interstellar Medium (DISM) of galaxies contains a component which exhibits efficient visible-near infrared luminescence ranging from 500 to 1000 nm, known as Extended Red Emission (ERE). Silicon nanocrystals (nc-Si) are discussed as possible carriers of the ERE. We employed the accelerator facilities of the Institute of Solid State Physics of the University of Jena to implant Si ions into fused silica windows. An excess concentration of silicon atoms is thus produced in the host SiO{sub 2} matrix which, by applying an annealing at 1100 C, condensates to silicon nanoparticles and crystallizes. Although the condensation and crystallization occur after an annealing of one minute,10, 15 the samples were annealed during one hour in order to well-passivate the nc-Si, that means, to reduce effectively the number of Si-dangling bonds at the nc-Si surface that are efficient non-radiative recombination centers. 10, 16 Upon excitation with UV light, most of our nc-Si/SiO{sub 2} samples revealed strong PL. We implanted into our luminescent nc-Si/SiO{sub 2} systems other atomic elements, as for instance magnesium and calcium, which form silicates if their oxide is combined with SiO{sub 2}. The purpose is to simulate the conditions for silicates containing nc-Si. In order to understand the effect of the incorporation of foreign atoms on the PL properties of our nc-Si/SiO{sub 2} systems, we proceeded to similar experiments with Er and Ge. As has been demonstrated by several authors, 17, 18 the presence of nc-Si in a glass matrix enhances considerably the emission of Er{sup 3+} ions at 1.536{mu}m. At the same time, the PL of nc-Si is considerably quenched. Since the solubility of Er in crystalline silicon is about 2 orders of magnitude lower than in SiO{sub 2}, the optically active Er{sup 3+} ions are believed to be localized outside the nc-Si core, demonstrating that ions present in the host SiO{sub 2} matrix influence the PL

  8. Pulsed IRSL: A stable and fast bleaching luminescence signal from feldspar for dating Quaternary sediments

    DEFF Research Database (Denmark)

    Tsukamoto, Sumiko; Kondo, Reisuke; Lauer, Tobias

    2017-01-01

    Elevated temperature post-infrared infrared stimulated luminescence (post-IR IRSL; pIRIR) dating method using feldspar has led to a significant advancement in dating Quaternary sediments, as this signal has been shown to be stable on geological time scales. In comparison to the conventional IRSL...... fading, when the signal is recorded during the off-time of LED stimulation pulses. In this study, we compare the signal bleachability, thermal and athermal stability, and age estimates derived using different measurement methods, i.e., pulsed IRSL measured at 50 °C (pulsed IR50; subscripts refers...... and tephrochronology. We observe that under exposure to solar simulator, the pulsed IR50 signal bleaches as rapidly as the CW IR50, and much more rapidly than the pIRIR signals. Furthermore, the pulsed IR50 signal is also as stable as the pIRIR signals, especially when the middle part of the decay curve is used...

  9. Pottery versus sediment: Optically stimulated luminescence dating of the Neolithic Vinča culture, Serbia

    DEFF Research Database (Denmark)

    Bate, Stephen; Stevens, Thomas; Buylaert, Jan-Pieter

    2017-01-01

    Optically stimulated luminescence (OSL) dating was applied to the Neolithic Vinča culture's type-site, Vinča Belo-Brdo, to establish best protocols for routine luminescence dating of similar Holocene sites, critical in understanding Neolithic to Chalcolithic cultural development. Equivalent dose ...

  10. Protocols for Thermoluninescence and Optically Stimulated Luminescence Research at DOSAR

    Energy Technology Data Exchange (ETDEWEB)

    Bernal, SM

    2004-10-11

    The Life Sciences Division (LSD) of Oak Ridge National Laboratory (ORNL) has a long record of radiation dosimetry research at the Dosimetry Applications Research (DOSAR) facility complex. These facilities have been used by a broad segment of the research community to perform a variety of experiments in areas including, but not limited to, radiobiology, radiation dosimeter and instrumentation development and calibration, and materials testing in a variety of radiation environments. Collaborations with the University of Tennessee-Knoxville (UTK) have also led to important contributions in the area of archaeometry, particularly as it relates to the use of radiation dosimetry to date archaeological artifacts. This manual is to serve as the primary instruction and operation manual for dosimetric and archaeometric research at DOSAR involving thermoluminescence (TL) and optically stimulated luminescence (OSL). Its purpose is to (1) provide protocols for common practices associated with the research, (2) outline the relevant organizational structure, (3) identify the Quality Assurance plan, and (4) describe all the procedures, operations, and responsibilities for safe and proper operation of associated equipment. Each person who performs research at DOSAR using TL/OSL equipment is required to read the latest revision of this manual and be familiar with its contents, and to sign and date the manual's master copy indicating that the manual has been read and understood. The TL/OSL Experimenter is also required to sign the manual after each revision to signify that the changes are understood. Each individual is responsible for completely understanding the proper operation of the TL/OSL equipment used and for following the guidance contained within this manual. The instructions, protocols, and operating procedures in this manual do not replace, supersede, or alter the hazard mitigation controls identified in the Research Safety Summary (''Thermoluminescence/Optically

  11. Modelling the thermal quenching mechanism in quartz based on time-resolved optically stimulated luminescence

    DEFF Research Database (Denmark)

    Pagonis, V.; Ankjærgaard, Christina; Murray, Andrew

    2010-01-01

    . As the temperature of the sample is increased, more electrons are removed from the excited state via the non-radiative pathway. This reduction in the number of available electrons leads to both a decrease of the intensity of the luminescence signal and to a simultaneous decrease of the luminescence lifetime. Several...... simulations are carried out of time-resolved optically stimulated luminescence (TR-OSL) experiments, in which the temperature dependence of luminescence lifetimes in quartz is studied as a function of the stimulation temperature. Good quantitative agreement is found between the simulation results and new...

  12. Stable helical solitons in optical media

    Indian Academy of Sciences (India)

    Boris Malomed; G D Peng; P L Chu; Isaac Towers; Alexander V Buryak; Rowland A Sammut

    2001-11-01

    We present a review of new results which suggest the existence of fully stable spinning solitons (self-supporting localised objects with an internal vorticity) in optical fibres with self-focusing Kerr (cubic) nonlinearity, and in bulk media featuring a combination of the cubic self-defocusing and quadratic nonlinearities. Their distinctive difference from other optical solitons with an internal vorticity, which were recently studied in various optical media, theoretically and also experimentally, is that all the spinning solitons considered thus far have been found to be unstable against azimuthal perturbations. In the first part of the paper, we consider solitons in a nonlinear optical fibre in a region of parameters where the fibre carries exactly two distinct modes, viz., the fundamental one and the first-order helical mode. From the viewpoint of application to communication systems, this opens the way to doubling the number of channels carried by a fibre. Besides that, these solitons are objects of fundamental interest. To fully examine their stability, it is crucially important to consider collisions between them, and their collisions with fundamental solitons, in (ordinary or hollow) optical fibres. We introduce a system of coupled nonlinear Schrödinger equations for the fundamental and helical modes with nonstandard values of the cross-phase-modulation coupling constants, and show, in analytical and numerical forms, results of collisions between solitons carried by the two modes. In the second part of the paper, we demonstrate that the interaction of the fundamental beam with its second harmonic in bulk media, in the presence of self-defocusing Kerr nonlinearity, gives rise to the first ever example of completely stable spatial ring-shaped solitons with intrinsic vorticity. The stability is demonstrated both by direct simulations and by analysis of linearized equations.

  13. Optical luminescence spectroscopy as a probe of the surface mineralogy of Mars

    Science.gov (United States)

    Treiman, A. H.

    1992-01-01

    Optical luminescence (OpL) spectroscopy is an attractive use of a visible-near-IR spectrometer on a Mars lander because mineral products of atmosphere-surface interactions on Mars will probably have characteristic OpL spectra. Optical luminescence spectra would be taken at night, when a spectrometer might otherwise sit idle. Also needed would be a source of exciting radiation, which could be shared with other experiments. Optical luminescence is emission of nonthermal optical photons (near-UV through near-IR) as a response to energy input. On absorption of energy, an atom (or ion) will enter an excited state. The favored decay of many such excited states involving valence-band electrons is emission of an optical photon. Optical luminescence spectra can be useful in determining mineralogy and mineral composition. Optical luminescence in crystals can arise from essential elements (or ions), trace-element substituents (activators), or defects. Common activators in salts of alkali and alkaline earth elements include Mn(2+)(VI), other transition metals, the rare earths, and the actinides. Trace substituents of other species can enhance or quench OpL (e.g., Pb(2+) vs. Fe(3+)). Optical luminescence can also arise from defects in crystal structures, including those caused by radiation and shock.

  14. Semiconducting Polymer Nanoparticles with Persistent Near-Infrared Luminescence for In Vivo Optical Imaging.

    Science.gov (United States)

    Palner, Mikael; Pu, Kanyi; Shao, Shirley; Rao, Jianghong

    2015-09-21

    Materials with persistent luminescence are attractive for in vivo optical imaging since they have a long lifetime that allows the separation of excitation of fluorophores and image acquisition for time-delay imaging, thus eliminating tissue autofluorescence associated with fluorescence imaging. Persistently luminescent nanoparticles have previously been fabricated from toxic rare-earth metals. This work reports that nanoparticles made of the conjugated polymer MEH-PPV can generate luminescence persisting for an hour upon single excitation. A near-infrared dye was encapsulated in the conjugated polymer nanoparticle to successfully generate persistent near-infrared luminescence through resonance energy transfer. This new persistent luminescence nanoparticles have been demonstrated for optical imaging applications in living mice.

  15. Hard X-ray-induced optical luminescence via biomolecule-directed metal clusters.

    Science.gov (United States)

    Osakada, Yasuko; Pratx, Guillem; Sun, Conroy; Sakamoto, Masanori; Ahmad, Moiz; Volotskova, Olga; Ong, Qunxiang; Teranishi, Toshiharu; Harada, Yoshie; Xing, Lei; Cui, Bianxiao

    2014-04-07

    Here, we demonstrate that biomolecule-directed metal clusters are applicable in the study of hard X-ray excited optical luminescence, promising a new direction in the development of novel X-ray-activated imaging probes.

  16. The origin and dynamics of soft X-ray-excited optical luminescence of ZnO.

    Science.gov (United States)

    Armelao, Lidia; Heigl, Franziskus; Brunet, Sophie; Sammynaiken, Ramaswami; Regier, Tom; Blyth, Robert I R; Zuin, Lucia; Sankari, Rami; Vogt, Johannes; Sham, Tsun-Kong

    2010-12-03

    The distinct optical emission from ZnO materials, nanoneedles and microcrystallites synthesized with different sizes and morphologies by a flow deposition technique, is investigated with X-ray excited optical luminescence (XEOL) and time-resolved X-ray excited optical luminescence (TR-XEOL) from a synchrotron light source at the O K and Zn L(3,2) edges. The innovative use of XEOL, allowing site-specific chemical information and luminescence information at the same time, is fundamental to provide direct evidence for the different behaviour and the crucial role of bulk and surface defects in the origin of ZnO optical emission, including dynamics. XEOL from highly crystalline ZnO nanoneedles is characterized by a sharp band-gap emission (~380 nm) and a broad red luminescence (~680 nm) related to surface defects. Luminescence from ZnO microcrystallites is mostly dominated by green emission (~510 nm) associated with defects in the core. TR-XEOL experiments show considerably faster decay dynamics in nanoneedles compared to microcrystallites for both band-gap emission and visible luminescence. Herein we make a fundamental step forward correlating for the first time the interplay of size, crystallinity, morphology and excitation energy with luminescence from ZnO materials.

  17. Multispectral Cerenkov luminescence tomography for small animal optical imaging.

    Science.gov (United States)

    Spinelli, Antonello E; Kuo, Chaincy; Rice, Brad W; Calandrino, Riccardo; Marzola, Pasquina; Sbarbati, Andrea; Boschi, Federico

    2011-06-20

    Quite recently Cerenkov luminescence imaging (CLI) has been introduced as a novel pre-clinical imaging for the in vivo imaging of small animals such as mice. The CLI method is based on the detection of Cerenkov radiation (CR) generated by beta particles as they travel into the animal tissues with an energy such that Cerenkov emission condition is satisfied. This paper describes an image reconstruction method called multi spectral diffuse Cerenkov luminescence tomography (msCLT) in order to obtain 3D images from the detection of CR. The multispectral approach is based on a set of 2D planar images acquired using a number of narrow bandpass filters, and the distinctive information content at each wavelength is used in the 3D image reconstruction process. The proposed msCLT method was tested both in vitro and in vivo using 32P-ATP and all the images were acquired by using the IVIS 200 small animal optical imager (Caliper Life Sciences, Alameda USA). Source depth estimation and spatial resolution measurements were performed using a small capillary source placed between several slices of chicken breast. The theoretical Cerenkov emission spectrum and optical properties of chicken breast were used in the modelling of photon propagation. In vivo imaging was performed by injecting control nude mice with 10 MBq of 32P-ATP and the 3D tracer bio-distribution was reconstructed. Whole body MRI was acquired to provide an anatomical localization of the Cerenkov emission. The spatial resolution obtained from the msCLT reconstructed images of the capillary source showed that the FWHM is about 1.5 mm for a 6 mm depth. Co-registered MRI images showed that the Cerenkov emission regions matches fairly well with anatomical regions, such as the brain, heart and abdomen. Ex vivo imaging of the different organs such as intestine, brain, heart and ribs further confirms these findings. We conclude that in vivo 3D bio-distribution of a pure beta-minus emitting radiopharmaceutical such as 32P

  18. Persistent luminescence induced by near infra-red photostimulation in chromium-doped zinc gallate for in vivo optical imaging

    Science.gov (United States)

    Sharma, Suchinder K.; Gourier, Didier; Teston, Eliott; Scherman, Daniel; Richard, Cyrille; Viana, Bruno

    2017-01-01

    The analysis of the optical spectroscopy of the Cr3+ doped spinel was initiated by Prof. Georges Boulon more than twenty years ago. More recently persistent luminescence nanoparticles of Cr doped zinc gallate have found interest for in vivo imaging of small animals. Here we evaluated near infra-red (NIR) excitation (or NIR photostimulation) via photo-transfer mechanism as an additional tool for in vivo optical imaging. Investigation of the persistent luminescence induced by NIR photostimulation is studied after either a primary UV (band-to-band excitation) or visible irradiation (direct Cr 3d-3d excitation). UV or visible pre-excited ZnGa2O4:Cr (ZGO:Cr) nanoparticles are kept active during several days thanks to deep traps (with depths 1 eV-1.2 eV) observed in these samples which can be probed through thermally stimulated luminescence (TSL) technique showing glow curve maximums at 470 K and 530 K upon visible light excitation. These deep traps are stable at room temperature but can be emptied by NIR light photostimulation. Experiments were carried out to study the photostimulation induced trapping-detrapping in the ZGO:Cr phosphor. Photostimulation was also tested in vivo for small animal optical imaging to offer new perspectives and modalities.

  19. Highly stable piezoelectrically tunable optical cavities

    CERN Document Server

    Möhle, Katharina; Döringshoff, Klaus; Nagel, Moritz; Peters, Achim

    2013-01-01

    We have implemented highly stable and tunable frequency references using optical high finesse cavities which incorporate a piezo actuator. As piezo material we used ceramic PZT, crystalline quartz, or PZN-PT single crystals. Lasers locked to these cavities show a relative frequency stability better than 1 x 10^{-14}, which is most likely not limited by the piezo actuators. The piezo cavities can be electrically tuned over more than one free spectral range (> 1.5 GHz) with only a minor decrease in frequency stability. Furthermore, we present a novel cavity design, where the piezo actuator is prestressed between the cavity spacer components. This design features a hermetically sealable intra cavity volume suitable for, e.g., cavity enhanced spectroscopy.

  20. Optimising the separation of quartz and feldspar optically stimulated luminescence using pulsed excitation

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Jain, Mayank; Thomsen, Kristina Jørkov;

    2010-01-01

    In luminescence dating, the two most commonly used natural minerals, quartz and feldspar, are exposed to different dose rates in the natural environment, and so record different doses. The luminescence signals also have different stabilities. For accurate dosimetry, the signals from these two...... minerals must be separated, either by physical separation of the mineral grains, or by instrumental separation of the luminescence signals. The luminescence signals from quartz and feldspar have different luminescence lifetimes under pulsed optical stimulation. This difference in lifetime can be used...... to discriminate between the two signals from a mixed quartz-feldspar sample. The purpose of this study is to identify optimum measurement conditions for the best separation of quartz OSL from that of feldspar in a mixed sample using pulsed stimulation and time-resolved OSL. We integrate the signal from 5 μs after...

  1. Optical stimulated Luminescence Signal on Modern Fluvial Deposit in Taiwan

    Science.gov (United States)

    Chen, Y. G.; Wu, T. S.; Chen, Y. W.; Kuo, Y. T.

    2014-12-01

    The river terraces overlain by fluvial and debris-flow deposit are widely distributed in Taiwan due to its active tectonic situation. They are not only critical in reconstructing the river evolution, but also of importance in understanding neotectonics. However, the age estimation for the terraces has their own problems by C-14 as well as OSL (Optical Stimulated Luminescence) dating method. For C-14 method, the major problem is the difficulty in discovering the suitable samples, but for OSL method the zeroing effect of the sediments becomes the major barrier if quartz SAR (Single Aliquot Regenerative) procedure is applied. In order to test the residual dose from different drainage areas in Taiwan, modern deposits were collected from 13 main rivers and 3 samples for each from upper-stream to downstream. The apparent dose of modern fluvial deposit was defined as residual dose and believed to be able to give a hint for estimating the zeroing effect for river terraces. Quartz SAR OSL procedure on small aliquot was adopted for all samples in this study. Our results show the residual dose in western Taiwan strongly relies on the source from. If we further apply the mean value of smallest 5% on samples from modern debris flow deposits in upper-stream, the residual dose rise up as high as ~40Gy but lower down to ~15Gy for samples collected from river mouth estuary. It implies that there will be a large error when evaluating the age of debris deposit terrace by quartz SAR OSL procedure. However, if the modern river does not suffer from debris flow in upper-stream, the residual dose is ~5Gy in upper stream and only -0.7~2Gy to the lower steam estuary, which provide better chance to derive relatively reliable ages. We also find that the luminescence characteristics is different between the samples in western and eastern Taiwan respectively. The quartz grains from eastern Taiwan are much dimer than those of the western Taiwan. We may therefore face severe challenge to approach

  2. Review of optically stimulated luminescence (OSL) instrumental developments for retrospective dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, Lars; Thomsen, Kristina Jørkov; Jain, Mayank

    2010-01-01

    This review describes 40 years of experience gained at Risø National Laboratory in the development of facilities for irradiation, thermal/optical stimulation and luminescence signal detection. These facilities have mainly been used in luminescence dating and nuclear accident dosimetry. We focus e...... especially on methods for light stimulation and irradiation, and developments of new portable TL/OSL readers for determining doses directly in the field on both Earth and the planet Mars....

  3. The temperature dependence of optically stimulated luminescence from α-Al2O3:C

    DEFF Research Database (Denmark)

    Markey, B.G.; McKeever, S.W.S.; Akselrod, M.S.

    1996-01-01

    The results of experimental measurements and computer simulations on optically stimulated luminescence (OSL) from alpha-Al2O3:C are described. The intensity of the OSL observed during illumination of irradiated specimens with visible light is temperature dependent. Optical stimulation is observed...

  4. X-ray excited optical luminescence, photoluminescence, photostimulated luminescence and x-ray photoemission spectroscopy studies on BaFBr:Eu

    CERN Document Server

    Subramanian, N; Govinda-Rajan, K; Mohammad-Yousuf; Santanu-Bera; Narasimhan, S V

    1997-01-01

    The results of x-ray excited optical luminescence (XEOL), photoluminescence (PL), photostimulated luminescence (PSL) and x-ray photoemission spectroscopy (XPS) studies on the x-ray storage phosphor BaFBr:Eu are presented in this paper. Analyses of XEOL, PL and PSL spectra reveal features corresponding to the transitions from 4f sup 6 td sup 1 to 4f sup 7 configurations in different site symmetries of Eu sup 2 sup +. Increasing x-ray dose is seen to lead to a red shift in the maximum of the PL excitation spectrum for the 391 nm emission. The XEOL and XPS spectra do not show any signature of Eu sup 3 sup + in the samples studied by us, directly raising doubts about the model of Takahashi et al in which Eu sup 2 sup + is expected to ionize to Eu sup 3 sup + upon x-ray irradiation and remain stable until photostimulation. XEOL and PSL experiments with simultaneous x-ray irradiation and He - Ne laser excitation as well as those with sequential x-ray irradiation and laser stimulation bring out the competition betwe...

  5. Solid-state luminescence for the optical examination of archaeological glass beads

    Science.gov (United States)

    Zacharias, N.; Beltsios, K.; Oikonomou, A.; Karydas, A. G.; Bassiakos, Y.; Michael, C. T.; Zarkadas, Ch.

    2008-03-01

    The work pertains to the application of solid-state luminescence as a characterization tool for glassy ceramic cultural artefacts. An archaeological glass bead collection excavated at the city of Thebes, Greece and considered as unique in terms of typological variety and time span was examined with the application of luminescence techniques (thermoluminescence, optically stimulated luminescence). Additionally, X-rays fluorescence (XRF) was used to provide non-destructively the elemental concentration profile of the samples. The thermoluminescence signals following laboratory irradiation provided distinct groups of spectra types according to the color classification of the samples. For each sample, the signal sensitivity and growth were examined using both thermoluminescence and optically stimulated luminescence recording. The study provides evidence for the usefulness of the combined application of luminescence and non-destructive, XRF-based, elemental analysis for the characterization of glass assemblages. Finally, due to the satisfactory level of radiation-induced signal intensity, the work suggests the possibility of chronological estimation of ancient glass beads using luminescence dating protocols.

  6. The temperature dependence of optically stimulated luminescence from α-Al2O3:C

    DEFF Research Database (Denmark)

    Markey, B.G.; McKeever, S.W.S.; Akselrod, M.S.;

    1996-01-01

    The results of experimental measurements and computer simulations on optically stimulated luminescence (OSL) from alpha-Al2O3:C are described. The intensity of the OSL observed during illumination of irradiated specimens with visible light is temperature dependent. Optical stimulation is observed...... from the main dosimetric traps, and from deep traps. The temperature dependence appears to be due to the presence of shallow traps, with a possible additional contribution from thermally assisted optical excitation....

  7. Ion beam induced luminescence of germano-silicate optical fiber preform

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hyunkyu; Kim, Jongyeol; Lee, Namho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Youngwoong; Han, Wontaek [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Markovic, Nikola; Jaksic, Milko [Ruder Boskovic Institute, Zagred (Croatia)

    2014-05-15

    When an optical fiber is exposed to radiation, the attenuation (RIA, Radiation Induced Attenuation) in the optical fiber (OF) is increased because of the color centers which deteriorate the transmission property and generate the absorption loss. In order to understand the radiation induced defect, Ion Beam induced luminescence (IBIL) was introduced to investigate it. IBIL technique is to analyze IR/VIS/UV luminescence related to ion beam interaction with outer shell electrons involved in chemical bonds and structure defects of target atoms. So IBIL is sensitive to its chemical composition and has been used in analysis of material characterization, geological samples and cultural heritage objects. In silica material, four O atoms are surrounding one Si atom in tetrahedral coordination. In this study, the influence of Copper (Cu) and Cerium (Ce) dopants to germano silica core optical fibers were investigated under proton irradiation at RBI using Ion Beam induced luminescence (IBIL) method. To understand the radiation induced defect of optical fibers, IBIL were tested to a germano-silica core fiber under 2 MeV proton irradiation. Although a Cu or Ce dopant was not detected by IBIL technique, the relation between the amount of radiation and luminescence can be established. This experiment showed a potential technique of studying the effects and behavior of additive elements for silica core fiber. To increase the radiation resistance of optical fibers, further investigations are needed, i. e. the proper additives and its contents and an interaction mechanism between Ge-related defects and additives.

  8. Optically stimulated luminescence of natural NaCl mineral from Dead Sea exposed to gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Roman L, J.; Cruz Z, E. [UNAM, Instituto de Ciencias Nucleares, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Pina L, Y. I. [UNAM, Facultad de Ciencias, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Marcazzo, J., E-mail: jesus.roman@nucleares.unam.mx [Instituto de Fisica Arroyo Seco - UNICEN, Pinto 399, 7000 Tandil (Argentina)

    2016-10-15

    Luminescence properties such as radioluminescence, thermoluminescence and optically stimulated luminescence have been studied on natural sodium chloride (NaCl) for dosimetric purposes in retrospective dosimetry (Timar-Gabor et al., 2013; Druzhyna et al., 2016). In this work, the optically stimulated luminescence (Cw-OSL) emissions of natural salt minerals, collected from Dead Sea in summer of 2015, were studied. The Cw-OSL dose response of natural salt was analyzed in the range between 0.2 and 10 Gy gamma dose of {sup 60}Co. Samples exposed at 3 Gy exhibited good repeatability with a variation coefficient of 4.6%. The thermal stability of the Cw-OSL response was analyzed to different temperatures from 50 up to 250 degrees Celsius using a heating rate of 5 degrees Celsius. The results showed that the natural Dead Sea salt minerals could be applied as natural dosimeter of gamma radiation. (Author)

  9. Optical imaging as an expansion of nuclear medicine: Cerenkov-based luminescence vs fluorescence-based luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Chin, Patrick T.K.; Welling, Mick M.; Leeuwen, Fijs W.B. van [Leiden University Medical Center, Interventional Molecular Imaging Laboratory, Department of Radiology, P.O. Box 9600, Leiden (Netherlands); Meskers, Stefan C.J. [Eindhoven University of Technology, Molecular Materials and Nanosystems, P.O. Box 513, Eindhoven (Netherlands); Valdes Olmos, Renato A. [Leiden University Medical Center, Interventional Molecular Imaging Laboratory, Department of Radiology, P.O. Box 9600, Leiden (Netherlands); Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Department of Nuclear Medicine, Amsterdam (Netherlands); Tanke, Hans [Leiden University Medical Center, Department of Molecular Cell Biology, P.O. Box 9600, Leiden (Netherlands)

    2013-08-15

    Integration of optical imaging technologies can further strengthen the field of radioguided surgery. Rather than using two separate chemical entities to achieve this extension, hybrid imaging agents can be used that contain both radionuclear and optical properties. Two types of such hybrid imaging agents are available: (1) hybrid imaging agents generated by Cerenkov luminescence imaging (CLI) of {beta}-emitters and (2) hybrid imaging agents that contain both a radioactive moiety and a fluorescent dye. One major challenge clinicians are now facing is to determine the potential value of these approaches. With this tutorial review we intend to clarify the differences between the two approaches and highlight the clinical potential of hybrid imaging during image-guided surgery applications. (orig.)

  10. Surface exposure dating of non-terrestrial bodies using optically stimulated luminescence

    DEFF Research Database (Denmark)

    Sohbati, Reza; Jain, Mayank; Murray, A.S.

    2012-01-01

    We propose a new method for in situ surface exposure dating of non-terrestrial geomorphological features using optically stimulated luminescence (OSL); our approach is based on the progressive emptying of trapped charge with exposure to light at depth into a mineral surface. A complete model...

  11. Optical absorption and luminescence in neutron-irradiated, silica-based fibers

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, D.W.; Farnum, E.H.; Clinard, F.W. [Los Alamos National Lab., CA (United States)] [and others

    1995-04-01

    The objectives of this work are to assess the effects of thermal annealing and photobleaching on the optical absorption of neutron-irradiated, silica fibers of the type proposed for use in ITER diagnostics, and to measure x-ray induced luminescence of unirradiated (virgin) and neutron-irradiated fibers.

  12. Developments in optically stimulated luminescence techniques for dating and retrospective dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Murray, A.S.

    1999-01-01

    Optically stimulated luminescence signals from natural quartz and feldspar are now used routinely in dating geological and archaeological materials. More recently they have also been employed in accident dosimetry, i.e. the retrospective assessment of doses received as a result of a nuclear accid...

  13. Optically stimulated luminescence response to Al2O3 to beta radiation

    DEFF Research Database (Denmark)

    Akselrod, A.; Akselrod, M.S.; Agersnap Larsen, N.

    1999-01-01

    High sensitivity dosemeters based on Al2O3:C have been prepared and tested for use as beta dosemeters using optically stimulated luminescence (OSL). Two types of sample were prepared and tested, namely unpolished thick, single crystal chips and thin powder layers on aluminium substrates...

  14. Surface exposure dating of non-terrestrial bodies using optically stimulated luminescence: A new method

    DEFF Research Database (Denmark)

    Sohbati, Reza; Jain, Mayank; Murray, Andrew

    2012-01-01

    We propose a new method for in situ surface exposure dating of non-terrestrial geomorphological features using optically stimulated luminescence (OSL); our approach is based on the progressive emptying of trapped charge with exposure to light at depth into a mineral surface. A complete model of t...

  15. Material and Optical Design Rules for High Performance Luminescent Solar Concentrators

    Science.gov (United States)

    Bronstein, Noah Dylan

    This dissertation will highlight a path to achieve high photovoltaic conversion efficiency in luminescent solar concentrators, devices which absorb sunlight with a luminescent dye and then re-emit it into a waveguide where it is ultimately collected by a photovoltaic cell. Luminescent concentrators have been studied for more than three decades as potential low-cost but not high efficiency photovoltaics. Astute application of the blackbody radiation law indicates that photonic design is necessary to achieve high efficiency: a reflective filter must be used to trap luminescence at all angles while allowing higher energy photons to pass through. In addition, recent advances in the synthesis of colloidal nanomaterials have created the possibility for lumophores with broad absorption spectra, narrow-bandwidth emission, high luminescence quantum yield, tunable Stokes shifts and tunable Stokes ratios. Together, these factors allow luminescent solar concentrators to achieve the optical characteristics necessary for high efficiency. We have fabricated and tested the first generation of these devices. Our experiments demonstrate that the application of carefully matched photonic mirrors and luminescent quantum dots can allow luminescent concentration factors to reach record values while maintaining high photon collection efficiency. Finally, the photonic mirror dramatically mitigates the negative impact of scattering in the waveguide, allowing efficient photon collection over distances much longer than the scattering length of the waveguide. After demonstrating the possibility for high performance, we theoretically explore the efficacy of luminescent concentrators with dielectric reflectors as the high-bandgap top-junctions in two-junction devices. Simple thermodynamic calculations indicate that this approach can be nearly as good as a traditional vertically stacked tandem. The major barriers to such a device are the optical design of narrow-bandwidth, angle

  16. Long persistent and optically stimulated luminescence behaviors of calcium aluminates with different trap filling processes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Buhao; Xu, Xuhui; Li, Qianyue; Wu, Yumei; Qiu, Jianbei; Yu, Xue, E-mail: yuyu6593@126.com

    2014-09-15

    Properties of long persistent luminescence (LPL) and optically stimulated luminescence (OSL) of CaAl{sub 2}O{sub 4}:Eu{sup 2+}, R{sup 3+} (R=Nd, Dy, Tm) materials were investigated. The observed phenomenon indicates that R{sup 3+} ions (R=Nd, Dy, Tm) have different effects on trap properties of CaAl{sub 2}O{sub 4}:Eu{sup 2+}. The greatly improved LPL performance was observed in Nd{sup 3+} co-doped samples, which indicates that the incorporation of Nd{sup 3+} creates suitable traps for LPL. While co-doping Tm{sup 3+} ions, the intensity of high temperature of thermoluminescence band in CaAl{sub 2}O{sub 4}:Eu{sup 2+} phosphors is enhanced for the formation of the most suitable traps which benefits the intense and stable OSL. These results suggest that the effective traps contributed to the LPL/OSL are complex, of which could be an aggregation formation with shallow and deep traps other than simple traps from co-doped R{sup 3+} ions. The mechanism presented in the end potentially provides explanations of why the OSL of CaAl{sub 2}O{sub 4}:Eu{sup 2+}, R{sup 3+} exhibits different read-in/read-out performance as well. - Graphical abstract: OSL emission spectra of Ca{sub 0.995}Al{sub 2}O{sub 4}:0.0025Eu{sup 2+}, 0.0025R{sup 3+} (R=Nd, Dy, Tm) taken under varying stimulation time (0, 25, 50, 75, 100 s). Inset: Blue emission pictures under varying stimulation time. - Highlights: • The LPL and OSL properties of CaAl{sub 2}O{sub 4}:Eu{sup 2+}, R{sup 3+} were investigated. • An alternative approach to control the trap depth of CaAl{sub 2}O{sub 4}:Eu{sup 2+} phosphor was proposed. • A new oxide ETM phosphor exhibiting intense and stable OSL was explored.

  17. Highly luminescent mono- and multilayers of immobilized CdTe nanocrystals: controlling optical properties through post chemical surface modification.

    Science.gov (United States)

    Tsuruoka, Takaaki; Takahashi, Rena; Nakamura, Toshihiro; Fujii, Minoru; Akamatsu, Kensuke; Nawafune, Hidemi

    2008-04-14

    The significant fluorescence enhancement of immobilized CdTe nanocrystals through chemical surface modifications is described, enabling us to fabricate stable, highly luminescent thin films and patterns of nanocrystal mono- and mutilayers.

  18. Thermoluminescence and optically stimulated luminescence dating of bricks from the Thung Tuk archaeological site, Southern Thailand

    Directory of Open Access Journals (Sweden)

    Santi Pailoplee

    2016-12-01

    Full Text Available Thermoluminescence (TL and optically stimulated luminescence (OSL based dating were applied to ancient fired bricks to derive the chronology of the Thung Tuk archaeological site (TT, southern Thailand. In order to test the feasibility of brick dating, the inside and outside portions of the brick mass were dated separately. From the obtained results, the outside portion of the brick mass was found to be more suitable for luminescence dating than the inside portion since the inside might be incompletely fired during the production process. Among the brick ages obtained using the outside portion, both the TL and OSL (with a minimum model analyses were all in agreement with the known ages of the TT, except for one sample that appeared to be much younger. This likely represents a subsequent renovation brick. Thus, the assessment of renovation and other imports into sites should be carefully considered in future luminescence dating.

  19. A Highly Stable 3D Luminescent Indium-Polycarboxylic Framework for the Turn-off Detection of UO2(2+), Ru(3+), and Biomolecule Thiamines.

    Science.gov (United States)

    Du, Ning; Song, Jian; Li, Shuang; Chi, Yu-Xian; Bai, Feng-Ying; Xing, Yong-Heng

    2016-10-17

    Hydrothermal reaction of the multidentate organic ligand (H6TTHA) with indium chloride (InCl3) produced a highly stable 3D luminescent indium-organic framework [In2(OH)2(H2TTHA)(H2O)2]n (1). Complex 1 exhibits remarkable luminescent properties, especially the multifunction sensitivity and selectivity for detecting Ru(3+), UO2(2+); as well as small biomolecules thiamines (TPP, TMP, and TCl) based on a "turn-off" manner. In particular, the pyrophosphate groups of TPP and the phosphate groups of TMP could further affect the quenching rate, leading to different luminescent responds. In addition, we also discussed and proved the luminescence quenching mechanism in detail through comparative test and PXRD characterization. Therefore, complex 1 could be used as a kind of excellent luminescence sensor to detect Ru(3+), UO2(2+), and thiamines (TPP, TMP, and TCl).

  20. Fabrication of stable lightweight Be-38Al optics and optical support structures

    Science.gov (United States)

    Hardesty, Robert; Parker, Kelsey

    2015-09-01

    This paper describes recent aerospace applications where Be-38Al (AlBeMet) has been successfully applied to produce optics and stable support structures. The information presented touches on historical uses of beryllium and beryllium-aluminum in satellite optical systems, and then presents recent uses and developments of Be-38Al and its application to optical substrates and stable support structures.

  1. Up-Conversion Photostimulated Luminescence of Mg2SnO4 for Optical Storage

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jia-Chi; QIN Qing-Song; YU Ming-Hui; SUN Jia-Yao; SHI Liu-Rong; MA Xin-Long

    2011-01-01

    @@ We report the first observation of up-conversion photostimulated luminescence in non-doped Mg2SnO4.Stimulated by 980 nm infrared laser (reading) after ultraviolet irradiation (writing), the phosphor shows photostimulated emission band covering 470-550nm, which is due to the recombination of F centers with holes.After ceasing ultraviolet irradiation, the storage intensity would rapidly decrease to 59% of its original storage intensity in 2.5h and then would not degrade anymore.It is suggested that the Mg2SnO4 has potential applications for optical storage.Accordingly, the possible photostimulated luminescence mechanisms of Mg2SnO4 are proposed.%We report the first observation of up-conversion photostimulated luminescence in non-doped Mg2SnO4. Stimulated by 980 nm infrared laser (reading) after ultraviolet irradiation (writing), the phosphor shows photostimulated emission band covering 470-550nm, which is due to the recombination of F centers with holes. After ceasing ultraviolet irradiation, the storage intensity would rapidly decrease to 59% of its original storage intensity in 2.5 h and then would not degrade anymore. It is suggested that the Mg2SnO4 has potential applications for optical storage. Accordingly, the possible photostimulated luminescence mechanisms of Mg2SnO4 are proposed.

  2. Limit of detection of a fiber optics gyroscope using a super luminescent radiation source

    CERN Document Server

    Sandoval, G E

    2003-01-01

    The main objective of this work is to establish the dependence of characteristics of the fiber optics gyroscope (FOG) with respect to the parameters of the super luminescent emission source based on doped optical fiber with rare earth elements (Super luminescent Fiber Source, SFS), argument the pumping rate election of the SFS to obtain characteristics limits of the FOG sensibility. By using this type of emission source in the FOG is recommend to use the rate when the direction of the pumping signal coincide with the super luminescent signal. The most results are the proposition and argumentation of the SFS election as emission source to be use in the FOG of the phase type. Such a decision allow to increase the characteristics of the FOG sensibility in comparison with the use of luminescent source of semiconductors emission which are extensively used in the present time. The use of emission source of the SFS type allow to come closer to the threshold of the obtained sensibility limit (detection limit) which i...

  3. New Nanomaterials and Luminescent Optical Sensors for Detection of Hydrogen Peroxide

    Directory of Open Access Journals (Sweden)

    Natalia A. Burmistrova

    2015-10-01

    Full Text Available Accurate methods that can continuously detect low concentrations of hydrogen peroxide (H2O2 have a huge application potential in biological, pharmaceutical, clinical and environmental analysis. Luminescent probes and nanomaterials are used for fabrication of sensors for H2O2 that can be applied for these purposes. In contrast to previous reviews focusing on the chemical design of molecular probes for H2O2, this mini-review highlights the latest luminescent nanoparticular materials and new luminescent optical sensors for H2O2 in terms of the nanomaterial composition and luminescent receptor used in the sensors. The nanomaterial section is subdivided into schemes based on gold nanoparticles, polymeric nanoparticles with embedded enzymes, probes showing aggregation-induced emission enhancement, quantum dots, lanthanide-based nanoparticles and carbon based nanomaterials, respectively. Moreover, the sensors are ordered according to the type of luminescent receptor used within the sensor membranes. Among them are lanthanide complexes, metal-ligand complexes, oxidic nanoparticles and organic dyes. Further, the optical sensors are confined to those that are capable to monitor the concentration of H2O2 in a sample over time or are reusable. Optical sensors responding to gaseous H2O2 are not covered. All nanomaterials and sensors are characterized with respect to the analytical reaction towards H2O2, limit of detection (LOD, analytical range, electrolyte, pH and response time/incubation time. Applications to real samples are given. Finally, we assess the suitability of the nanomaterials to be used in membrane-based sensors and discuss future trends and perspectives of these sensors in biomedical research.

  4. Stable Optical Phase Modulation with Micromirrors

    CERN Document Server

    Knoernschild, Caleb; Maunz, Peter; Crain, Stephen; Kim, Jungsang

    2011-01-01

    We measure the motional fluctuations of a micromechanical mirror using a Michelson interferometer, and demonstrate its interferometric stability. The position stability of the micromirror is dominated by the thermal mechanical noise of the structure. With this level of stability, we utilize the micromirror to realize an ideal optical phase modulator by simply reflecting light off the mirror and modulating its position. The resonant frequency of the modulator can be tuned by applying a voltage between the mirror and an underlying electrode. Full modulation depth of +/-\\pi is achieved when the mirror resonantly excited with a sinusoidal voltage at an amplitude of 11V.

  5. Luminescent Properties of Arylpolyene Organic Dyes and Cross-Conjugated Ketones Promising for Quantum Optics and Nanophotonics Applications

    Directory of Open Access Journals (Sweden)

    Naumova N. L.

    2015-01-01

    Full Text Available The spectral-luminescent properties of some dyes of substituted arylpolyenes and cross-conjugated ketones class in Shpolsky matrices, promising for using in solving quantum optics and nanophotonics, were studied.

  6. Photoluminescence and Optically Stimulated Luminescence Studies of LiAlO2 and LiGaO2 Crystals

    Science.gov (United States)

    2015-03-26

    PHOTOLUMINESCENCE AND OPTICALLY STIMULATED LUMINESCENCE STUDIES OF LiAlO2 AND LiGaO2 CRYSTALS THESIS Ian P. Ferguson, Second Lieutenant, USAF AFIT...STIMULATED LUMINESCENCE STUDIES OF LiAlO2 AND LiGaO2 CRYSTALS THESIS Presented to the Faculty Department of Engineering Physics Graduate School of...FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. AFIT-ENP-MS-15-M-106 PHOTOLUMINESCENCE AND OPTICALLY STIMULATED LUMINESCENCE STUDIES OF LiAlO2 AND LiGaO2

  7. Optical fibre dosemeter systems for clinical applications based on radioluminescence and optically stimulated luminescence from Al2O3:C

    DEFF Research Database (Denmark)

    Marckmann, C.J.; Andersen, C.E.; Aznar, M.C.

    2006-01-01

    Optical fibre dosemeter systems based on radioluminescence and optically stimulated luminescence (OSL) from carbon-doped aluminium oxide (Al2O3:C) crystals were developed for in vivo real-time dose rate and absorbed dose measurements in radiotherapy and mammography. A technique was also developed...... for making ultra-small dosemeter probes that can easily be placed inside patients in radiation treatment. These probes have shown excellent properties in both head and neck intensity-modulated radiation therapy treatment and in mammography. The dose-response of the OSL signal for the new optical fibre...

  8. Optical temperature sensing based on the luminescence from YAG:Pr transparent ceramics

    Science.gov (United States)

    Hu, Song; Lu, Chunhua; Liu, Xiaoxia; Xu, Zhongzi

    2016-10-01

    The YAG:Pr transparent ceramic was fabricated using a conventional solid-state reactive method to explore its possible application in optical thermometry. Photoluminescence and temperature-dependent luminescence were elaborately investigated under 452 nm excitation. The ceramic showed two intrinsic emission bands at 488 and 594 nm, which were attributed to characteristic Pr3+: 3P0 → 3H4 and 3P1 → 3H6 transitions, respectively. Down-conversion emissions from the two thermally coupled excited states of Pr3+ were recorded in the temperature range of 293-593 K. The Boltzmann distribution theory was adopted to interpret the temperature-dependent luminescence of Pr3+. The temperature sensitivity exhibited an increasing trend with the increase of temperature, typically, 0.0025 K-1 at 593 K. The results indicated that the present ceramic was a promising candidate for optical temperature sensor.

  9. Further investigations into pulsed optically stimulated luminescence from feldspars using blue and green light

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Jain, Mayank; Kalchgruber, R.

    2009-01-01

    The purpose of this paper is to investigate characteristics of luminescence signals resulting from pulsed optical stimulation of feldspars and thereby to understand the underlying processes giving rise to the signal. Fourteen different feldspar specimens were investigated using time...... suggests that the TR-OSL signal decay is governed by the recombination process and not by the excited state lifetime. Furthermore data from the TR-OSL signal dependence on stimulation time and preheat temperature suggest that the recombination process may not be a sum of exponentials, although the model......-resolved optically stimulated luminescence (TR-OSL), and these signals can be mathematically described as a sum of 4 exponential components (a, b, c, d). The slowest component, d, increases with the duration of the light pulse as expected from the exponential model. The stimulation temperature dependence experiment...

  10. Optically stimulated luminescence (OSL) as a chronometer for surface exposure dating

    DEFF Research Database (Denmark)

    Sohbati, Reza; Murray, Andrew S.; Chapot, Melissa S.

    2012-01-01

    We pioneer a technique of surface-exposure dating based upon the characteristic form of an optically stimulated luminescence (OSL) bleaching profile beneath a rock surface; this evolves as a function of depth and time. As a field illustration of this new method, the maximum age of a premier examp......, at decadal to millennial timescales or perhaps longer (depending on the environmental dose rate) even for material subsequently buried. This has considerable potential in many archeological, geological and geo-hazard applications....

  11. A high sensitivity optically stimulated luminescence scanning system for measurement of single sand-sized grains

    DEFF Research Database (Denmark)

    Duller, G.A.T.; Bøtter-Jensen, L.; Kohsiek, P.;

    1999-01-01

    An instrument has been designed for the routine analysis of the optically stimulated luminescence signal from single grains of sand. The system is capable of analysing over 3000 individual grains in a single measurement sequence, and the OSL signal from each grain can be read in less than 3 s....... The design principles are described, along with preliminary measurements that illustrate the operation of the system and its capabilities....

  12. Fiber Optic Cable Thermal Preparation to Ensure Stable Operation

    Science.gov (United States)

    Thoames Jr, William J.; Chuska, Rick F.; LaRocca, Frank V.; Switzer, Robert C.; Macmurphy, Shawn L.; Ott, Melanie N.

    2008-01-01

    Fiber optic cables are widely used in modern systems that must provide stable operation during exposure to changing environmental conditions. For example, a fiber optic cable on a satellite may have to reliably function over a temperature range of -50 C up to 125 C. While the system requirements for a particular application will dictate the exact method by which the fibers should be prepared, this work will examine multiple ruggedized fibers prepared in different fashions and subjected to thermal qualification testing. The data show that if properly conditioned the fiber cables can provide stable operation, but if done incorrectly, they will have large fluctuations in transmission.

  13. X-ray excited optical luminescence studies on the system Ba (, =F, Cl, Br, I)

    Indian Academy of Sciences (India)

    K Govinda Rajan; A Jestin Lenus

    2005-08-01

    The present paper reports the experimental observations on the x-ray excited optical luminescence (XEOL) along with the afterglow and colour center features found for the barium salts, represented by the formula, Ba, where and are the halides. The system thus consists of four dihalides (BaF2, . . . ,BaI2) and six mixed halides (BaFCl,. . . ,BaBrI). To start with, it was found that on two of the binary halides of barium, BaClI and BaBrI, no literature exists, and so these were prepared for the first time and their crystal structures were determined. An x-ray generator of 3-kW rating was next coupled to a spectrometer via a high throughput fiberoptic sensor for recording the luminescence spectra under x-irradiation. Also presented in this paper are the observations on the Ba compounds in which about 0.1 mole% of Eu2+ was doped, in order to study the efficiency between the prompt luminescence and the photostimulated luminescence in these compounds. The crystal structure varies from fluorite (BaF2), to matlockite (BaF) and finally to orthorhombic (BaCl2, . . .,BaBrI) for these compounds. Hence searching for systematics and empirical relations in the observed XEOL behaviour of these compounds is still a challenging problem.

  14. A study on the real-time radiation dosimetry measurement system based on optically stimulated luminescence

    Institute of Scientific and Technical Information of China (English)

    LIU Yan-Ping; CHEN Zhao-Yang; BA Wei-Zhen; FAN Yan-Wei; DU Yan-Zhao; PAN Shi-Lie; GUO Qi

    2008-01-01

    The optically stimulated luminescent (OSL) radiation dosimeter technically surveys a wide dynamic measurement range and a high sensitivity.Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-acoess and hazardous.In addition.optical fiber dosimeters are immune to electrical and radio-frequency interference.In this paper,a novel remote optical fiber radiation dosimeter is described.The optical fiber dosimeter takes advantage of the charge trapping materials CaS:Ce, Sm that exhibit OSL.The measuring range of the dosimeter is from 0.1 to 100 Gy.The equipment is relatively simple and small in size,and has low power consumption.This device is suitable for measuring the space radiation dose and also can be used in high radiation dose condition and other dangerous radiation occasions.

  15. Luminescence and scintillation properties of YAG:Ce single crystal and optical ceramics

    CERN Document Server

    Mihóková, E; Mareš, J A; Beitlerová, A; Vedda, A; Nejezchleb, K; Blažek, K; D’Ambrosio, C

    2007-01-01

    We use various techniques to study optical and scintillation properties of Ce-doped yttrium aluminum garnet, Y3Al5O12 (YAG:Ce), in the form of a high-quality industrial single crystal. This was compared to optical ceramics prepared from YAG:Ce nanopowders. We present experimental data in the areas of optical absorption, radioluminescence, scintillation decay, photoelectron yield, thermally stimulated luminescence and radiation-induced absorption. The results point to an interesting feature—the absence of antisite (YAl, i.e. Y at the Al site) defects in optical ceramics. The scintillation decay of the ceramics is faster than that of the single crystal, but its photoelectron yield (measured with 1 μs integration time) is about 30–40% lower. Apart from the photoelectron yield value the YAG:Ce optical ceramic is fully comparable to a high quality industrial YAG:Ce single crystal and can become a competitive scintillator material.

  16. Anisotropy of optical absorption and luminescent properties of CaMoO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Zakharko, Ya., E-mail: zakharko@electronics.wups.lviv.u [Faculty of Electronics, Ivan Franko National University of Lviv, 107 Tarnavskogo St., 79017 Lviv (Ukraine); Luchechko, A. [Faculty of Electronics, Ivan Franko National University of Lviv, 107 Tarnavskogo St., 79017 Lviv (Ukraine); Syvorotka, I.; Stryganyuk, G.; Solskii, I. [Institute for Materials, SRC ' Carat' , 202 Stryjska St., 79031 Lviv (Ukraine)

    2010-03-15

    Optical absorption, excitation and emission spectra, as well as photoluminescence decay time of CaMoO{sub 4} single crystals have been measured. It has been revealed that annealing of crystals in oxygen atmosphere leads to the disappearance of their anisotropic behavior in optical absorption, as well as in X-ray luminescence and decay time. Moreover, it has been found that annealing can significantly affect the value of the decay time. The relative intensity of the long-wavelength emission band increases under excitation in the region of indirect band-to-band transitions.

  17. A new sensitive system for measurement of thermally and optically stimulated luminescence

    DEFF Research Database (Denmark)

    Markey, B.G.; Bøtter-Jensen, L.; Poolton, N.R.J.

    1996-01-01

    An automatic system developed at RisO National Laboratory for measuring thermally and optically stimulated luminescence (TL, OSL) is widely used for radiation dose measurements. In the present model, high excitation and detection efficiencies were attempted, but inevitably there is a constant...... optics of the system with a combination of ellipsoidal mirrors and light guides, which also serve to make the system more flexible in choice of excitation source when OSL measurements are required. A variety of new light sources might be employed, adapted to allow the most efficient wavelengths...

  18. Highly luminescent, stable, transparent and flexible perovskite quantum dot gels towards light-emitting diodes

    Science.gov (United States)

    Sun, Chun; Shen, Xinyu; Zhang, Yu; Wang, Yu; Chen, Xingru; Ji, Changyin; Shen, Hongzhi; Shi, Hengchong; Wang, Yiding; Yu, William W.

    2017-09-01

    By controlling the hydrolysis of alkoxysilanes, highly luminescent, transparent and flexible perovskite quantum dot (QD) gels were synthesized. The gels could maintain the structure without shrinking and exhibited excellent stability comparing to the QDs in solution. This in situ fabrication can be easily scaled up for large-area/volume gels. The gels integrated the merits of the polymer matrices to avoid the non-uniformity of light output, making it convenient for practical LED applications. Monochrome and white LEDs were fabricated using these QD gels; the LEDs exhibited broader color gamut, demonstrating better property in the backlight display application.

  19. Stable rotating dipole solitons in nonlocal optical media

    DEFF Research Database (Denmark)

    Lopez-Aguayo, Servando; Desyatnikov, Anton S.; Kivshar, Yuri S.

    2006-01-01

    We reveal that nonlocality can provide a simplæe physical mechanism for stabilization of multihump optical solitons and present what we believe to be the first example of stable rotating dipole solitons and soliton spiraling, which we are known to be unstable in all types of realistic nonlinear...

  20. Lanthanide upconversion luminescence at the nanoscale: fundamentals and optical properties.

    Science.gov (United States)

    Nadort, Annemarie; Zhao, Jiangbo; Goldys, Ewa M

    2016-07-01

    Upconversion photoluminescence is a nonlinear effect where multiple lower energy excitation photons produce higher energy emission photons. This fundamentally interesting process has many applications in biomedical imaging, light source and display technology, and solar energy harvesting. In this review we discuss the underlying physical principles and their modelling using rate equations. We discuss how the understanding of photophysical processes enabled a strategic influence over the optical properties of upconversion especially in rationally designed materials. We subsequently present an overview of recent experimental strategies to control and optimize the optical properties of upconversion nanoparticles, focussing on their emission spectral properties and brightness.

  1. Lanthanide upconversion luminescence at the nanoscale: fundamentals and optical properties

    Science.gov (United States)

    Nadort, Annemarie; Zhao, Jiangbo; Goldys, Ewa M.

    2016-07-01

    Upconversion photoluminescence is a nonlinear effect where multiple lower energy excitation photons produce higher energy emission photons. This fundamentally interesting process has many applications in biomedical imaging, light source and display technology, and solar energy harvesting. In this review we discuss the underlying physical principles and their modelling using rate equations. We discuss how the understanding of photophysical processes enabled a strategic influence over the optical properties of upconversion especially in rationally designed materials. We subsequently present an overview of recent experimental strategies to control and optimize the optical properties of upconversion nanoparticles, focussing on their emission spectral properties and brightness.

  2. Synthesis of highly luminescent water stable ZnO quantum dots as photoluminescent sensor for picric acid

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Kulvinder; Chaudhary, G.R.; Singh, Sukhjinder; Mehta, S.K., E-mail: skmehta@pu.ac.in

    2014-10-15

    Highly luminescent, water stable (3-aminopropyl) triethoxysilane capped ZnO quantum dots (QDs) have been synthesized using a simple solution route. The synthesized ZnO QDs have been characterized using X-ray diffraction (XRD), Transmission electron microscopy (TEM), Particle size analyzer (PSA), UV–visible (UV–vis), Photoluminescence (PL) and Fourier transform infrared (FTIR) spectroscopy. The PL studies demonstrate that the particles synthesized are highly luminescent in nature emitting yellow color on exposure to UV radiation. Further, PL emission of ZnO QDs in the presence of picric acid (PA) shows their high sensitivity and selectivity for PA. The superior response of ZnO QDs in the presence of PA makes them very effective PL sensors. The limit of detection comes out to be 2.86 µM. - Highlights: • ZnO QDs act as photoluminiscent sensor for picric acid in aqueous medium. • Sensor shows high selectivity and sensitivity with a detection limit of 2.86 μM. • More the number of nitro groups, more is the quenching in PL emission of ZnO QDs.

  3. Tuning the Upconversion Luminescence Lifetimes of KYb2 F7 :Ho(3+) Nanocrystals for Optical Multiplexing.

    Science.gov (United States)

    Ding, Mingye; Chen, Daqin; Ma, Danyang; Liu, Peng; Song, Kaixin; Lu, Hongwei; Ji, Zhenguo

    2015-12-21

    Conventional luminescent color coding is limited by spectral overlap and the interference of background fluorescence, thus restricting the number of distinguishable identities that can be used in practice. Here, we demonstrate the possibility of generating diverse time-domain codes, specially designed for a single emission band, using lanthanide-doped upconversion nanocrystals. Based on the knowledge of concentration quenching, the upconversion luminescence kinetics of KYb2 F7 : Ho(3+) nanocrystals can be precisely controlled by modifying the dopant concentration of Ho(3+) ions, resulting in a tunable emission lifetime from 75.8 to 1944.5 μs, which suggests the practicality of these time-domain codes for optical multiplexing. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. SEMICONDUCTOR PHYSICS Dose-rate dependence of optically stimulated luminescence signal

    Science.gov (United States)

    Pingqiang, Wei; Zhaoyang, Chen; Yanwei, Fan; Yurun, Sun; Yun, Zhao

    2010-10-01

    Optically stimulated luminescence (OSL) is the luminescence emitted from a semiconductor during its exposure to light. The OSL intensity is a function of the total dose absorbed by the sample. The dose-rate dependence of the OSL signal of the semiconductor CaS doped Ce and Sm was studied by numerical simulation and experiments. Based on a one-trap/one-center model, the whole OSL process was represented by a series of differential equations. The dose-rate properties of the materials were acquired theoretically by solving the equations. Good coherence was achieved between numerical simulation and experiments, both of which showed that the OSL signal was independent of dose rate. This result validates that when using OSL as a dosimetry technique, the dose-rate effect can be neglected.

  5. Stable luminescent metal-organic frameworks as dual-functional materials to encapsulate ln(3+) ions for white-light emission and to detect nitroaromatic explosives.

    Science.gov (United States)

    Xie, Wei; Zhang, Shu-Ran; Du, Dong-Ying; Qin, Jun-Sheng; Bao, Shao-Juan; Li, Jing; Su, Zhong-Min; He, Wen-Wen; Fu, Qiang; Lan, Ya-Qian

    2015-04-06

    A stable porous carbazole-based luminescent metal-organic framework, NENU-522, was successfully constructed. It is extremely stable in air and acidic/basic aqueous solutions, which provides the strategy for luminescent material encapsulation of Ln(3+) ions with tunable luminescence for application in light emission. More importantly, Ln(3+)@NENU-522 can emit white light by encapsulating different molar ratios of Eu(3+) and Tb(3+) ions. Additionally, Tb(3+)@NENU-522 is found to be useful as a fluorescent indicator for the qualitative and quantitative detection of nitroaromatic explosives with different numbers of -NO2 groups, and the concentrations of complete quenching are about 2000, 1000, and 80 ppm for nitrobenzene, 1,3-dinitrobenzene, and 2,4,6-trinitrophenol, respectively. Meanwhile, Tb(3+)@NENU-522 displays high selectivity and recyclability in the detection of nitroaromatic explosives.

  6. Luminescence and optical absorption determination in porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Nogal, U.; Calderon, A.; Marin, E.; Rojas T, J. B.; Juarez, A. G., E-mail: u_nogal@hotmail.com [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Calz. Legaria No. 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico)

    2012-10-15

    We applied the photoacoustic spectroscopy technique in order to obtain the optical absorption spectrum in porous silicon samples prepared by electrochemical anodic etching on n-type, phosphorous doped, (100)-oriented crystal-line silicon wafer with thickness of 300 {mu}m and 1-5 {omega}cm resistivity. The porous layers were prepared with etching times of 13, 20, 30, 40 and 60 minutes. Also, we realized a comparison among the optical absorption spectrum with the photoluminescence and photo reflectance ones, both obtained at room temperature. Our results show that the absorption spectrum of the samples of porous silicon depends notably of the etching time an it consist of two distinguishable absorption bands, one in the Vis region and the other one in the UV region. (Author)

  7. Investigation of Optical and Luminescence Properties of Soda Lime Borate Glasses Doped with Sm3+ Ion

    Institute of Scientific and Technical Information of China (English)

    FALAK; Zaman; GUL; Rooh; NATTAPON; Srisittipokakun; JACKRAPONG; Kaewkhao

    2016-01-01

    This paper was to investigate the optical and luminescence properties of Sm3+ doped SLB glasses by a melt quenching technique. The optical and luminescence properties of the prepared glass samples were investigated via absorption and photoluminescence spectra, respectively. The related physical and optical parameters were also calculated. From optical absorption measurements, the transition 6H5/2 → 6P3/2 at 403 nm has a higher spectral intensity and is a hypersensitive transition. From photoluminescence spectra, four prominent emission spectra appear. The most intense band is located at 4G5/2 →6H9/2(599 nm), which is the characteristic emission range of Sm3+ ions with the reddish orange color. The experimental decay time of the 4G5/2 level of Sm3+ SLB glasses was determined. The decay time decreases from 1.367 to 0.333 ms with increasing the content of Sm3+. The color coordinates(x, y) of the prepared glasses passes through the reddish-orange region in the CIE 1931 diagram and are suitable for orange LEDs, optoelectronics, and solidstate lighting. The further investigation on the optimization of the dopant content in the SLB glasses was suggested.

  8. Measurement and Optimization of Metal-Nanoparticle-Induced Luminescence Enhancement Factors in a Crossed-Optical Fiber Configuration

    Directory of Open Access Journals (Sweden)

    Maria Veronica Rigo

    2010-01-01

    Full Text Available A crossed-optical-fiber configuration comprised of silver nanoparticles covalently attached to the core of an optical fiber and labeled with luminescent ruthenium molecules is reported. A second optical fiber was placed at right angle of the fiber containing the nanoparticle/ruthenium, to form a fiber-fiber junction, and it was used to detect the luminescence from the ruthenium molecules bound to the first fiber. To employ the effect of metal-enhanced luminescence, the ruthenium complex was kept at an appropriate distance from the nanoparticles by polyelectrolyte spacer layers. For silver nanospheres, nanotriangles and nanorods and for spacer-layer thicknesses from 2–14 nm luminescence-enhancement factors were determined. A 27-fold luminescence enhancement was found when the ruthenium complex was placed 4 nm from silver nanotriangles. Finally, a calibration curve for the oxygen dependence of luminescence intensities and lifetimes of ruthenium complex is presented suggesting that the oxygen sensing capabilities of the nanoengineered-ruthenium complex are maintained.

  9. An optically stimulated luminescence study of flint related to radiation dosimetry

    DEFF Research Database (Denmark)

    Poolton, N.R.J.; Bøtter-Jensen, L.; Rink, W.J.

    1995-01-01

    This article describes the essential features of photo-stimulated luminescence in flint. The emission is shown to be complex, arising from a number of different aspects of the material. Under constant illumination, dose-dependent time-decaying anti-Stokes signals are superimposed on dose......-independent, time-stable emission that is both Stokes and anti-Stokes shifted in energy. It is argued that the dose-dependent signals arise from the crystalline quartz phase of the material, whereas the dose independent signals originate from an amorphous-like phase of SiO2. The microcrystallinity of the material...

  10. Real-time optical-fibre luminescence dosimetry for radiotherapy: physical characteristics and applications in photon beams

    DEFF Research Database (Denmark)

    Aznar, M.C.; Andersen, C.E.; Bøtter-Jensen, L.;

    2004-01-01

    A new optical-fibre radiation dosimeter system, based on radioluminescence and optically stimulated luminescence from carbon-doped aluminium oxide, was developed and tested in clinical photon beams. This prototype offers several features, such as a small detector (1 x 1 x 2 mm), high sensitivity...

  11. Optically stimulated luminescence (OSL) of dental enamel for retrospective assessment of radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Yukihara, E.G. [Department of Physics, Oklahoma State University, Stillwater, OK 74078 (United States)], E-mail: eduardo.yukihara@okstate.edu; Mittani, J.; McKeever, S.W.S. [Department of Physics, Oklahoma State University, Stillwater, OK 74078 (United States); Simon, S.L. [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-7238 (United States)

    2007-07-15

    This paper briefly reviews the optically stimulated luminescence (OSL) properties of dental enamel and discusses the potential and challenges of OSL for filling the technology gap in biodosimetry required for medical triage following a radiological/nuclear accident or terrorist event. The OSL technique uses light to stimulate a radiation-induced luminescence signal from materials previously exposed to ionizing radiation. This luminescence originates from radiation-induced defects in insulating crystals and is proportional to the absorbed dose of ionizing radiation. In our research conducted to date, we focused on fundamental investigations of the OSL properties of dental enamel using extracted teeth and tabletop OSL readers. The objective was to obtain information to support the development of the necessary instrumentation for retrospective dosimetry using dental enamel in laboratory, or for in situ and non-invasive accident dosimetry using dental enamel in emergency triage. An OSL signal from human dental enamel was detected using blue, green, or IR stimulation. Blue/green stimulation associated with UV emission detection seems to be the most appropriate combination in the sense that there is no signal from un-irradiated samples and the shape of the OSL decay is clear. Improvements in the minimum detection level were achieved by incorporating an ellipsoidal mirror in the OSL system to maximize light collection. Other possibilities to improve the sensitivity and research steps necessary to establish the feasibility of the technique for retrospective assessment of radiation exposure are also discussed.

  12. X-ray-excited optical luminescence of impurity atom in semiconductor.

    Science.gov (United States)

    Ishii, M; Tanaka, Y; Komuro, S; Morikawa, T; Aoyagi, Y; Ishikawa, T

    2001-03-01

    We observed the x-ray-excited optical luminescence (XEOL) of erbium-doped silicon (Si:Er) thin films to make a site-selective x-ray absorption fine structure (XAFS) measurement of an optically active Er atom. The undulator beam was used for the increment of the electron population in the excited state, and following XEOL at an infrared wavelength of 1.54 microm with minimum absorption loss in the host Si was detected. The edge-jump and XAFS oscillation were successfully obtained at the Er L(III)-edge. This spectrum originated from inner-shell excitation and relaxation of only the optically active Er atom, indicating that site-selectivity at an atomic level was achieved.

  13. Optical filtering and luminescence property of some molybdates prepared by combustion synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, P. J., E-mail: yadav.pooja75@yahoo.in [Department of Electronics, RTM Nagpur University, Nagpur (India); Joshi, C. P. [Physics Department, RCOEM, Nagpur (India); Moharil, S. V., E-mail: svmoharil@yahoo.com [Physics Department, RTM Nagpur University, Nagpur (India)

    2014-10-15

    As an important class of lanthanide inorganic compounds, rare earth ions doped molybdates have gained much attention due to their attractive luminescence and structural properties, supporting various promising applications as phosphor materials in the fields such as white light-emitting diodes, optical fibers, biolabel, lasers, and so on. The molybdate family has promising trivalent cation conducting properties and most of the optical properties result from electron transitions of the 4f shell, which are greatly affected by the composition and structures of rare-earth compounds. In this paper we report the molybdate CaMoO{sub 4}:Eu{sup 3+} for red SSL and Bi{sub 1.4}Y{sub 0.6}MoO{sub 6}, Y{sub 6}MoO{sub 12} for optical filtering, prepared by one step combustion synthesis.

  14. Luminescent conjugated oligothiophenes: optical dyes for revealing pathological hallmarks of protein misfolding diseases

    Science.gov (United States)

    Hammarström, Per; Lindgren, Mikael; Nilsson, K. Peter R.

    2010-08-01

    Luminescent conjugated polymers (LCPs) have been frequently utilized for optical biosensors. The detection schemes of these sensors are employing the light harvesting properties or the conformation sensitive optical properties of the conjugated polymers. LCPs have been utilized as colorimetric and fluorescent sensing elements for the recording of biological processes. However, LCPs have several limitations for being used as real time in vivo imaging agents. In this regard, novel thiophene based molecular scaffolds, denoted luminescent conjugated oligothiophenes (LCOs) have been developed. These LCOs are chemically defined molecules having distinct side chain functionalizations and a precise number of thiophene units. Herein the utilization of LCOs as specific ligands for the pathological hallmarks underlying protein misfolding diseases, such as Alzheimer's disease, is described. The use of the conformation sensitive optical properties of the LCOs for spectral separation of these pathological entities in a diversity of in vitro, ex vivo or in vivo systems is demonstrated. The protein aggregates are easily identified due to the conformation-dependent emission profile from the LCOs and spectral assignment of protein aggregates can be obtained. Overall, these probes will offer practical research tools for studying protein misfolding diseases and facilitate the study of the molecular mechanism underlying these disorders.

  15. Optically stimulated luminescence in KCl:Cu x-irradiated at room temperature

    CERN Document Server

    Bandyopadhyay, P K; Chakrabarti, K

    1999-01-01

    Optically stimulated luminescence (OSL) has been observed in single crystals of KCl:Cu x-irradiated at room temperature. It is shown that electrons are liberated from anion sites during the OSL process. The OSL predominantly involves emission due to radiative transition (d s) of monovalent copper ions present in the lattice. The OSL emission shows a strong temperature dependence indicating a thermally assisted process. Electron-hole recombination followed by energy transfer to the Cu activator is suggested as a possible OSL mechanism in KCl:Cu. Preliminary results of OSL in KBr:Cu are also presented.

  16. Glucose optical fibre sensor based on a luminescent molecularly imprinted polymer

    Science.gov (United States)

    Elosua, C.; Wren, S. P.; Sun, T.; Arregui, F. J.; Grattan, Kenneth T. V.

    2015-09-01

    An optrode able to detect glucose dissolved in water has been implemented. The device is based on the luminescence emission of a Molecularly Imprinted Polymer synthesized specifically for glucose detection, therefore its intensity changes in presence of glucose. This sensing material is attached onto a cleaved ended polymer-clad optical fibre and it is excited by light via 1x2 fibre coupler. The reflected fluorescence signal increases when it is immersed into glucose solutions and recovers to the baseline when it is dipped in ultrapure water. This reversible behaviour indicates the measurement repeatability of using such a glucose sensor.

  17. Gamma response characterizations of optically stimulated luminescence (OSL) affects personal dosimetry

    Science.gov (United States)

    Monthonwattana, S.; Esor, J.; Rungseesumran, T.; Intang, A.

    2017-06-01

    Optically Stimulated Luminescence (OSL) is the current technique of personal dosimetry changed by Nuclear Technology Service Center instead of Thermoluminescence dosimetry (TLD) because OSL has more advantages, such as repeat reading and elimination of heating process. In this study, OSL was used to test the gamma response characterizations. Detailed OSL investigation on personal dosimetry was carried out in the dose range of 0.2 - 3.0 mSv. The batch homogeneity was 7.66%. R2 value of the linear regression was 0.9997. The difference ratio of angular dependence at ± 60° was 8.7%. Fading of the reading was about 3%.

  18. Surface exposure dating of non-terrestrial bodies using optically stimulated luminescence: A new method

    DEFF Research Database (Denmark)

    Sohbati, Reza; Jain, Mayank; Murray, Andrew

    2012-01-01

    We propose a new method for in situ surface exposure dating of non-terrestrial geomorphological features using optically stimulated luminescence (OSL); our approach is based on the progressive emptying of trapped charge with exposure to light at depth into a mineral surface. A complete model of t...... charge population. The potential dating applications for (a) include dust accumulation, volcanic rocks and impact-related sediments, and for (b) fault scarps, rock-falls, landslides and ice-scoured bedrock. Using assumptions based on terrestrial observations we expect that this approach...

  19. A method to remove residual signals in fibre optic luminescence dosimeters.

    Science.gov (United States)

    Lee, J J; Liu, P Z Y; McKenzie, D R; Suchowerska, N

    2013-03-07

    Whenever a fibre optic is used to convey a light signal through a radiation field, it is likely that an unwanted background signal will arise from Cerenkov or fluorescent light which will contaminate the signal. In luminescence dosimetry of high energy beams, when a fibre optic is used to convey the signal from the radiation field to the detector, Cerenkov light is the dominant contributor to the background signal and must be corrected for. In this work, a novel method is demonstrated to separate the signal from the unwanted background. A remotely operated shutter is used to block the signal, allowing the residual background in the fibre optic to be quantified. This background is subtracted from the total measurement acquired in a subsequent irradiation, enabling the luminescence signal to be extracted. Two types of shutter mechanism are considered: an electro-mechanical device to intercept the light path and an LCD device to block the light by cross-polarization. Both shutters were characterized and incorporated into a fibre optic dosimetry system used to measure the radiation dose produced by external beam radiation linear accelerators. The dosimeter using each of the shutters in turn was exposed to a 6 MV photon beam to determine their performance, including the measurement of field size dependent output factors. The mechanical shutter determined the output factors to within 0.29% of those measured with an ionization chamber, whereas the LCD shutter gave results that deviated by up to 2.4%. The switching precision of both shutters was good with standard deviations of less than 0.25% and both were able to completely block the light signal when closed. The use of shutters could therefore be applied to any fibre optic based system to quantify and remove a reproducible background arising from any source including ambient, fluorescent and Cerenkov light.

  20. Synchrotron generated X-ray Excited Optical Luminescence (XEOL) from Quartz

    Science.gov (United States)

    King, Georgina; Finch, Adrian; Robinson, Ruth

    2010-05-01

    Quartz is the preferred mineral for optically stimulated luminescence (OSL) dating, due to its well constrained behaviour as a radiation dosimeter. However, despite the plethora of successful quartz OSL applications, no solution has been found to the problem that some quartz luminesce more brightly than others, which has limited the application of OSL in certain settings. This has been addressed through examination of the luminescence emission using a variety of excitation techniques and emission spectroscopy. X-ray Excited Optical Luminescence (XEOL) is luminescence excited by x-rays produced by a synchrotron. XEOL analyses were conducted upon a suite of quartz samples at Diamond, Great Britain, which had previously been analysed with Ionoluminescence (IL), at Sussex University. The samples were selected to include quartz of both poor and excellent OSL sensitivities. Therefore, two Scottish glacial outwash samples prepared at St Andrews, and a calibration quartz sample, prepared at the Risø National Laboratory in Denmark were analysed for these properties respectively. The XEOL emission spectra comprised three major emissions at 3.32, 3.81 and 4.05 eV, and one weaker emission at 1.94 eV in all samples. The calibration quartz sample had the most intense emission by an order of magnitude. Throughout increased exposure to x-rays, the intensity of the UV emission reduced, and an increase in the red (1.94 eV) emission was recorded. The derived XEOL spectra complement the IL spectra obtained previously. The IL spectra were dominated by only two broad emissions at 3.2-3.1 eV and 1.8-1.7 eV. However, throughout the IL experiments a dose dependent effect was also observed, whereby the UV emission was depleted to the benefit of the red with increasing exposure. Furthermore the gradient of the power law relationship between the UV and red emission change with dose is similar for both the IL and XEOL data: at -1.15 and -1.05 respectively for calibration quartz, when plotted

  1. Thermally and optically stimulated luminescence of new ZnO nano phosphors exposed to beta radiation

    Energy Technology Data Exchange (ETDEWEB)

    Cruz V, C.; Burruel I, S.E.; Grijalva M, H.; Chernov, V.; Bernal, R. [Universidad de Sonora, A.P. 130, 83000 Hermosillo, Sonora (Mexico)

    2006-07-01

    In this work, we report the thermoluminescence (TL) and the optically stimulated luminescence (OSL) of ZnO nano phosphors obtained by thermal annealing of ZnS powders synthesized by precipitation in a chemical bath deposition reaction. To obtain nanocrystalline ZnO, ZnS pellet-shaped samples were subjected to a sintering process at 700 C during 24 under air atmosphere. Some samples were exposed to beta particles in the 0.15-10.15 kGy dose range and the integrated thermoluminescence as a function of dose increased as dose increased, with no saturation clue for the tested doses. Computerized glow-curve deconvolution of the experimental TL curves in individual peaks revealed a second order kinetics. In order to test the BOSL (Blue Optically Stimulated Luminescence) response, samples were beta irradiated with doses up to 600 Gy, showing an increasing OSL intensity as dose increases. From the experimental results that we have obtained, we conclude that the new ZnO phosphors under investigation are good candidates to be used as dosimetric materials. (Author)

  2. Measurement of solid-state optical refrigeration by two-band differential luminescence thermometry

    Energy Technology Data Exchange (ETDEWEB)

    Hehlen, Markus P [Los Alamos National Laboratory; Epstein, Richard I [Los Alamos National Laboratory; Patterson, Wendy M [UNM; Sheik - Bahae, Mansoor [UNM; Seletskiy, D V [UNM

    2009-01-01

    We present a non-contact spectroscopic teclmique for the measurement of laser-induced temperature changes in solids. Two-band differential luminescence thermometry (TBDLT) achieves a sensitivity of {approx}7 mK and enables precise measurement of the net quantum efficiency of optical refrigerator materials. TBDLT detects internal temperature changes by decoupling surface and bulk heating effects via time-resolved luminescence spectroscopy. Several Yb{sup 3+}-doped fluorozirconate (ZBLANI) glasses fabricated from precursors of varying purity and by different processes are analyzed in detail. A net quantum efficiency of 97.39% at 238 K (at a pump wavelength of 1020.5 nm) is found for a ZBLANI:1%Yb{sup 3+} laser-cooling sample produced from metal fluoride precursors that were purified by chelate-assisted solvent extraction and dried in hydrofluoric gas. In comparison, a ZBLANI:1%Yb{sup 3+} sample produced from commercial-grade metal fluoride precursors showed pronounced laser-induced heating that is indicative of a substantially higher impurity concentration. TBDLT enables rapid and sensitive benchmarking of laser-cooling materials and provides critical feedback to the development and optimization of high-performance optical cryocooler materials.

  3. Independent evaluation of optically stimulated luminescence (OSL) 'dot' dosemeters for environmental monitoring.

    Science.gov (United States)

    Timilsina, Bindu; Gesell, Thomas F

    2011-01-01

    Optically stimulated luminescence (OSL) 'dot' dosemeters (manufactured by Landauer®) are reported to have a high degree of environmental stability, high level of sensitivity and provide wide range of dose measuring capabilities from 0.05 mGy to 100 Gy. The optical read out method is fast and relatively simple and permits repeated read out, but few studies have been performed about its application in monitoring radiation in the environment. This study was initiated to independently test the performance of OSL dot dosemeters for the application of measuring doses of radiation in the outdoor environment. Testing was performed in the laboratory to evaluate reproducibility and stability and in the field to evaluate accuracy relative to calibrated high-pressure ionisation chambers. The results showed that OSL dot dosemeters had good reproducibility and stability in both laboratory and field tests and met the performance requirements of standards of the American National Standards Institute.

  4. Proliferation-resistant stable isotope separation based on optical pumping

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Cheol-Jung; Park, Hyunmin; Ko, Kwang-Hoon; Lim, Gwon; Kim, Taek-Soo; Rho, Sipyo; Cha, Yong-Ho; Han, Jamin; Jeong, Do-Young [Korea Atomic Energy Research Institute, Deajeon (Korea, Republic of). Quantum Optics Division

    2008-07-01

    Korea Atomic Energy Research Institute (KAERI) has developed the laser stable isotope separation based on optical pumping which can be applied to isotopes with small isotopic shift, provides high enrichment, is economical owing to high efficiency, and is proliferation-resistant. KAERI's laser isotope separation is based on isotope-selective optical pumping by very narrow bandwidth continuous wave laser followed by efficient infrared photo-ionization. KAERI demonstrated the pilot production of Tl-203 enriching over 97 % and separating 100 mg/hr. KAERI also demonstrated the separation of Yb-168 over 30 % and Yb- 176 over 97 % with tens of mg/hr. KAERI plans to scale up the production of Tl-203 up to 500 mg/hr and apply it to separation of Zn-67, Zn-70, Ba-130 and Ca-48 which are very important in medical industry and basic sciences. (author)

  5. Charge recombination processes in minerals studied using optically stimulated luminescence and time-resolved exo-electrons

    DEFF Research Database (Denmark)

    Tsukamoto, Sumiko; Murray, Andrew; Ankjærgaard, Christina

    2010-01-01

    electron concentration in the conduction band. In this study, TR-OSE and time-resolved optically stimulated luminescence (TR-OSL) were measured for the first time using quartz, K-feldspar and NaCl by stimulating the samples using pulsed blue LEDs at different temperatures between 50 and 250 °C after beta...

  6. Soil development rates from an optically stimulated luminescence-dated beach ridge sequence in Northern Jutland, Denmark

    DEFF Research Database (Denmark)

    Nielsen, Asger Habekost; Elberling, Bo; Pejrup, Morten

    2010-01-01

    of each pedon and soil stratum was measured by optically stimulated luminescence (OSL) dating and used to estimate soil development rates. Soils were divided into five groups from Typic Haplorthods and Entic Alorthods with a mean OSL age of 29659294 yr to Typic Quartzipsamments with a mean OSL age...

  7. Secondary Students' Stable and Unstable Optics Conceptions Using Contextualized Questions

    Science.gov (United States)

    Chu, Hye-Eun; Treagust, David F.

    2014-04-01

    This study focuses on elucidating and explaining reasons for the stability of and interrelationships between students' conceptions about Light Propagation and Visibility of Objects using contextualized questions across 3 years of secondary schooling from Years 7 to 9. In a large-scale quantitative study involving 1,233 Korean students and 1,149 Singaporean students, data were analyzed from responses to the Light Propagation Diagnostic Instrument consisting of four pairs of items, each of which evaluated the same concept in two different problem situations. Findings show that only about 10-45 % of students could apply their conceptions of basic optics in contextualized problem situations giving rise to both stable and unstable alternative conceptions. Students' understanding of Light Propagation concepts compared with Visibility of Objects concepts was more stable in different problem situations. The concepts of Light Propagation and Visibility of Objects were only moderately correlated. School grade was not a strong predictive variable, but students' school achievement correlated strongly with their conceptual understanding in optics. The teaching and learning approach and education systems in the two countries may have had some influence on students' conceptual understanding.

  8. Luminescence optically stimulated: theory and applications; Luminiscencia opticamente estimulada: teoria y aplicaciones

    Energy Technology Data Exchange (ETDEWEB)

    Rivera M, T.; Azorin N, J. [Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, 09340 Mexico D.F. (Mexico)

    2002-07-01

    The thermally stimulated luminescence (Tl) has occupied an important place in the Solid state physics (FES) by the flexibility of the phenomena, mainly for its applications in the fields of Radiation Physics (FR) and Medical Physics (MF). The reason of this phenomena lies in the fact of the electrons release by the action of heat. Under that same reason, it can be used the action of another stimulant agent for releasing the trapped electrons in the metastable states (EM), this agent is the light which has the same effect that the heat, giving as result the production of light photons at using light in the visible spectra, of different wavelength that the excitation light. This phenomena is called Luminescence optically stimulated (LOE). The LOE has a great impact in the Solid State Physics (FES), dating and now in the use of the phenomena as a dosimetric method, alternate to the Tl, for its use in the ionizing and non-ionizing radiations fields. (Author)

  9. Effects of heat treatment on physical, microstructural and optical characteristics of PbS luminescent nanocrystals

    Science.gov (United States)

    Mozafari, Masoud; Moztarzadeh, Fathollah; Vashaee, Dayoosh; Tayebi, Lobat

    2012-04-01

    The oxidation of lead sulfide (PbS) luminescent nanocrystals (NCs) considerably changes their luminescence characteristics. Hence, an understanding of the oxidation mechanism, the structure and properties of oxidized moieties is important. In this research, well-defined spherical PbS NCs were synthesized via a simple, effective and surfactant-free method and characterized. Then, the effects of heat treatment (at 250, 350, 450 and 550 °C) on the PbS NCs were investigated. The transmission electron microscope (TEM) micrographs of the synthesized PbS NCs revealed that they had a well-defined spherical morphology. In addition, the average crystallite size using Scherrer's formula was about 13 nm and the calculated lattice constant using Bragg's equation was 0.5950 nm, which was very close to the value in the standard card (JCPDS No. 5-592). Furthermore, the X-ray diffraction (XRD) revealed that the heat treatment of samples at temperatures of 250, 350,450 and 550 °C in air results in the formation of oxide sulfate phase of the compositions PbSO4 and PbO·PbSO4. The lattice parameter, crystallite size, average internal stress, micro-strain and optical properties of PbS NCs were calculated and correlated with the heat-treatment temperature.

  10. Tuning the luminescence and optical properties of graphene oxide and reduced graphene oxide functionnalized with PVA

    Science.gov (United States)

    Goumri, Meryem; Venturini, Jany Wéry; Bakour, Anass; Khenfouch, Mohammed; Baitoul, Mimouna

    2016-03-01

    The attractive optoelectronic properties of graphene are universally known. Also, their combination with polymer matrix added an exciting physical investigation. In the present work, nanocomposites based on poly (vinyl alcohol) (PVA) with low graphene oxide (GO) and partially reduced graphene oxide (PRGO) loadings (0.5, 1 and 2 wt%) were successfully prepared by a simple and environmentally friendly process using aqueous solution in both acidic (pH 4) and neutral media (pH 7)and optimized sonication time, in order to tailor the optical/electronic properties of the GO/PRGO nanosheets. FT-IR and Raman scattering spectroscopy reveal a strong interfacial interaction by hydrogen bonding between the two components. Steady-state photoluminescence results showed a pH-dependent fluorescence of these nanocomposites, and a significant luminescence over a wide range of the visible wavelengths was achieved at a concentration of 1 wt% GO and PRGO loading. A quenching of the PL started at 2 wt% suggesting the possibility of tuning the luminescence properties of GO/PRGO-based composites with PVA.

  11. Optically stimulated luminescence dating of cave deposits at the Xiaogushan prehistoric site, northeastern China.

    Science.gov (United States)

    Zhang, Jia-Fu; Huang, Wei-Wen; Yuan, Bao-Yin; Fu, Ren-Yi; Zhou, Li-Ping

    2010-11-01

    The Xiaogushan cave site is one of the most important prehistoric sites in North China. The stone and bone artifacts found in the cave are similar to European contemporaneous artifacts. Cave deposits consist of five layers that have been dated from 46,353 ± 1179 to 4229 ± 135 cal. yr BP, using radiocarbon dating techniques on charcoal and bone samples collected from Layers 2-5. In this paper, optically stimulated luminescence (OSL) techniques were applied to date six samples taken from Layers 1-3. The luminescence properties of the fine-grained and coarse-grained quartz extracts indicate that the materials are suitable for OSL dating using a single-aliquot regeneration-dose (SAR) protocol. The OSL ages obtained are broadly consistent with the stratigraphy and the associated calibrated radiocarbon ages. The dating results show that the cave was first occupied by humans about 70 ka. The human occupation of the cave may be related to climate change. An occupation hiatus is inferred to between ∼ 17 to ∼ 10 ka. The stone and bone artifacts found in Layers 2 and 3 may indicate the Middle to Upper Paleolithic transitions in the region.

  12. Optically stimulated luminescence from quartz measured using the linear modulation technique

    DEFF Research Database (Denmark)

    Bulur, E.; Bøtter-Jensen, L.; Murray, A.S.

    2000-01-01

    The optically stimulated luminescence (OSL) from heated natural quartz has been investigated using the linear modulation technique (LMT), in which the excitation light intensity is increased linearly during stimulation. In contrast to conventional stimulation, which usually produces a monotonically...... stimulated component occurs at a shorter time. This allows the separation of the overlapping OSL components, which are assumed to originate from different traps. The LM-OSL curve from quartz shows an initial peak Followed by a broad one. Deconvolution using curve fitting has shown that the composite OSL...... curve from quartz can be approximated well by using a linear combination of first-order peaks. In addition to the three known components, i.e. fast, medium and slow components from continuous-wave-OSL studies, an additional slow component is also identified for the first time. The dose responses...

  13. Using soils for accident dosimetry: a preliminary study using optically stimulated luminescence from quartz

    DEFF Research Database (Denmark)

    Fujita, Hiroki; Jain, Mayank; Murray, Andrew S.

    2011-01-01

    The optimum conditions of preheat temperature, stimulation temperature, etc. in the single-aliquot regenerative optically stimulated luminescence (SAR OSL) method were examined specifically for measuring background dose in natural quartz extracted from soils collected around Tokai-mura in Japan....... The objective was to assess the potential of SAROSL dosimetry using soils for retrospective assessment of a radiation accident. Variation in dose with depth was also measured. The SAR data showed good reproducibility and dose recovery, and there was no evidence of fading of the quartz signal based on “delayed......, and no clear trend in dose depth profile was observed. From these results, we conclude that SAR OSL dosimetry using natural quartz extracted from soil could be used to evaluate the dose of an accident....

  14. Synthesis, characterisation, optical and luminescence properties of CoAl{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Agilandeswari, K.; Kumar, A. Ruban, E-mail: arubankumarvit@gmail.com [School of Advanced Sciences, VIT University, Vellore, Tamil Nadu, India-632014 (India)

    2015-06-24

    Solid state method has been used as an efficient method to synthesize blue pigment CoAl{sub 2}O{sub 4} at a temperature of 800°C. The products were characterized by powder X-ray diffraction (XRD), Fourier transformer infrared spectroscopy (FTIR), UV-Visible diffuse reflectance spectroscopy (DRS) and luminescent spectroscopy. X-ray diffraction pattern confirmed the formation of single phase CoAl{sub 2}O{sub 4}. Optical properties of CoAl{sub 2}O{sub 4} ceramic shows an energy band gap in the range of 3.10eV. The emission spectra of spinel CoAl{sub 2}O{sub 4} in the visible region confirmed the presence of tetrahedral coordinated Co{sup 2+} ions.

  15. Developments in optically stimulated luminescence techniques for dating and retrospective dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Murray, A.S.

    1999-01-01

    Optically stimulated luminescence signals from natural quartz and feldspar are now used routinely in dating geological and archaeological materials. More recently they have also been employed in accident dosimetry, i.e. the retrospective assessment of doses received as a result of a nuclear...... accident. Since 1990, the exploration of this wide variety of applications has driven an intensive investigation and development programme at Riso in measurement facilities and techniques. This paper reviews some of the outcomes of this programme, including (i) optimisation of stimulation and emission...... windows, and detection sensitivity, (ii) experience with various stimulation light sources, including filtered incandescent lamps and high intensity light emitting diodes and laser diodes (infrared at 830-850 nm, blue-green at 420-550 nm and blue at 470 nm). Also discussed are recently developed high...

  16. Evaluation of Dynamic Optical Projection of Acquired Luminescence for Sentinel Lymph Node Biopsy in Large Animals.

    Science.gov (United States)

    Ringhausen, Elizabeth; Wang, Tylon; Pitts, Jonathan; Sarder, Pinaki; Akers, Walter J

    2016-12-01

    Open surgery requiring cytoreduction still remains the primary treatment course for many cancers. The extent of resection is vital for the outcome of surgery, greatly affecting patients' follow-up treatment including need for revision surgery in the case of positive margins, choice of chemotherapy, and overall survival. Existing imaging modalities such as computed tomography, magnetic resonance imaging, and positron emission tomography are useful in the diagnostic stage and long-term monitoring but do not provide the level of temporal or spatial resolution needed for intraoperative surgical guidance. Surgeons must instead rely on visual evaluation and palpation in order to distinguish tumors from surrounding tissues. Fluorescence imaging provides high-resolution, real-time mapping with the use of a contrast agent and can greatly enhance intraoperative imaging. Here we demonstrate an intraoperative, real-time fluorescence imaging system for direct highlighting of target tissues for surgical guidance, optical projection of acquired luminescence (OPAL). Image alignment, accuracy, and resolution was determined in vitro prior to demonstration of feasibility for operating room use in large animal models of sentinel lymph node biopsy. Fluorescence identification of regional lymph nodes after intradermal injection of indocyanine green was performed in pigs with surgical guidance from the OPAL system. Acquired fluorescence images were processed and rapidly reprojected to highlight indocyanine green within the true surgical field. OPAL produced enhanced visualization for resection of lymph nodes at each anatomical location. Results show the optical projection of acquired luminescence system can successfully use fluorescence image capture and projection to provide aligned image data that is invisible to the human eye in the operating room setting. © The Author(s) 2015.

  17. Optically stimulated luminescence (OSL) dating of quartzite cobbles from the Tapada do Montinho archaeological site (east-central Portugal)

    DEFF Research Database (Denmark)

    Sohbati, Reza; Murray, Andrew S.; Buylaert, Jan-Pieter

    2012-01-01

    The burial age of an alluvially deposited cobble pavement at the Tapada do Montinho archaeological site (east-central Portugal) is investigated using optically stimulated luminescence (OSL) dating. Measurements on the cobbles (quartzite clasts) were carried out on intact slices and large aliquots...... luminescence characteristics. The variation in the natural OSL signal with depth below the cobble surface using intact slices from two different cobbles shows that both were bleached to a depth of at least similar to 2?mm before deposition. A model of the variation of dose with depth fitted to data from one...... contained within a single clast, and this suggests that the luminescence dating of rock surfaces may prove, in the future, to be at least as important as sand/silt sediment dating....

  18. Tailoring of the luminescent ions local environment in optical fibers, and applications

    CERN Document Server

    Dussardier, Bernard; Peterka, P

    2012-01-01

    The chapter is situated in the fields of fiber materials sciences and technologies (particularly dealing with the fiber glass compositions and luminescent ion doping, and transparent glass ceramic optical fibers), and applications such as fiber lasers and amplifiers. We propose to present a review of research activities on rare-earth (RE) and transition metals (TM) doped silica-based optical fibers, aiming at understanding theier spectral properties, and particularly some of their optical transitions that will allow interesting and alternative applications. Silica, as opposed to alternative, low temperature materials, is chosen for practical and economical reasons. Selected RE and TM ions are studied both as probes of their local environment and for their application potentials. In this chapter, we will focus on erbium (Er) ions for the potential spectral 'tailoring' of its gain curve at 1.55 $\\mu$m, thulium (Tm) as local environment probe along both near infrared transitions around 0.8 and 1.47 $\\mu$m, and c...

  19. Dose-dependent optically stimulated luminescence of synthetic quartz at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kale, Y.D. [Luminescence Research Laboratory, Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Vadodara (India); Gandhi, Y.H. [Luminescence Research Laboratory, Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Vadodara (India)], E-mail: yasheshgandhi@yahoo.co.in; Gartia, R.K. [Luminescence Dating Laboratory, Department of Physics, Manipur University, Imphal (India)

    2008-12-15

    Physical conditions such as annealing temperature, duration of annealing, ionizing radiation, etc., play a significant role in the applications of optically stimulated luminescence (OSL) dating as well as OSL dosimetry. Many efforts are made to understand the effect of these physical parameters on quartz specimens owing to its use in such applications. Such factors induce changes in OSL decay pattern. The definite correlation between color centers and luminescence sensitivity can be established on account of such pre-treatments to the specimen. The purpose of present investigations is to study the effect of ionizing radiation under identical physical conditions on OSL properties measured at room temperature. The shapes of decay curve and dose-response data are considered for this purpose. This study can reveal the changes in color centers in response to the pre-conditions to the specimen. It was found that the OSL decay remains slow and OSL properties change systematically with the rise in beta dose up to a critical dose; however, it changes the pattern when the beta exposure to the specimen was increased higher than the critical dose. This critical dose was found to be different for different temperature of annealing. The shape of decay curve up to the critical dose was also studied by considering the difference of OSL intensities between two successive durations from the observed OSL decay data. The results are explained based on the changes in available shallow traps during OSL measurement at room temperature with changes in pre-conditions to the specimens. The results also have been confirmed with the corresponding changes in ESR signals.

  20. Optically stimulated luminescence techniques in retrospective dosimetry using single grains of quartz extracted from unheated materials

    Energy Technology Data Exchange (ETDEWEB)

    Joerkov Thomsen, Kristina

    2004-02-01

    This work investigates the possibility of applying optically stimulated luminescence (OSL) in retrospective dose determinations using unheated materials. It focuses on identifying materials suitable for use in assessment of doses absorbed as a consequence of radiation accidents (i.e. accident dosimetry). Special attention has been paid to quartz extracted from unheated building materials such as concrete and mortar. The single-aliquot regeneration-dose (SAR) protocol has been used to determine absorbed doses in small aliquots as well as single grains of quartz. It is shown that OSL measurements of single grains of quartz extracted from poorly-bleached building materials can provide useful information on radiation accident doses, even when the luminescence sensitivity is low. Sources of variance in well-bleached single grain dose distributions have been investigated in detail and it is concluded that the observed variability in the data is consistent with the sum (in quadrature) of a component, which depends on the number of photons detected from each grain, and a fixed component independent of light level. Dose depth profiles through laboratory irradiated concrete bricks have successfully been measured and minimum detection limits of less than 100 mGy are derived. Measurements of thermal transfer in single grains of poorly-bleached quartz show that thermal transfer is variable on a grain-to-grain basis and that it can be a source of variance in single-grain dose distributions. Furthermore, the potential of using common household and workplace chemicals, such as table salt, washing powder and water softener, in retrospective dosimetry has been investigated. It is concluded that such materials should be considered as retrospective dosimeters in the event of a radiation accident. (au)

  1. A new sensitive system for measurement of thermally and optically stimulated luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Markey, B.G.; Boetter-Jensen, L.; Poolton, N.R.J.; Christensen, H.E.; Willumsen, F. [Risoe National Lab., Roskilde (Denmark)

    1996-12-31

    An automatic system developed at Riso National Laboratory for measuring thermally and optically stimulated luminescence (TL, OSL) is widely used for radiation dose measurements. In the present model, high excitation and detection efficiencies were attempted, but inevitably there is a constant demand for improvements that would allow lower doses (or less sensitive materials) to be measured, with increased accuracy. This article reports on a new generation of designs that are intended to meet these demands. Substantial increases in sensitivity of the instruments are made by replacing the lens optics of the system with a combination of ellipsoidal mirrors and light guides, which also serve to make the system more flexible in choice of excitation source when OSL measurements are required. A variety of new light sources might be employed, adapted to allow them most efficient wavelengths of excitation to be used for the particular dosemeter under study. The capabilities and characteristics of the new design are described, and comparison with the existing TL/OSL system is made throughout the article. (author).

  2. Stable spatial and spatiotemporal optical soliton in the core of an optical vortex

    CERN Document Server

    Adhikari, S K

    2015-01-01

    We demonstrate a robust, stable, mobile, two-dimensional (2D) spatial and three-dimensional (3D) spatiotemporal optical soliton in the core of an optical vortex, while all nonlinearities are of the cubic (Kerr) type. The 3D soliton can propagate with a constant velocity along the vortex core without any deformation. Stability of the soliton under a small perturbation is established numerically. Two such solitons moving along the vortex core can undergo a quasi-elastic collision at medium velocities. Possibilities of forming such a 2D spatial soliton in the core of a vortical beam are discussed.

  3. Luminescence techniques: Instrumentation and methods

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.

    1997-01-01

    This paper describes techniques, instruments and methods used in luminescence dating and environmental dosimetry in many laboratories around the world. These techniques are based on two phenomena - thermally stimulated luminescence and optically stimulated luminescence. The most commonly used...... luminescence stimulation and detection techniques are reviewed and information is given on recent developments in instrument design and on the stale of the art in luminescence measurements and analysis. (C) 1998 Elsevier Science Ltd. All rights reserved....

  4. Study of optically stimulated luminescence (OSL) for radiation detection. Application to an optical fibre {gamma}-radiation sensor; Etude de la luminescence stimulee optiquement (OSL) pour la detection de rayonnements: application a un capteur a fibre optique de rayonnement {gamma}

    Energy Technology Data Exchange (ETDEWEB)

    Roy, O. [CEA Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Electronique et d`Instrumentation Nucleaire]|[Paris-7 Univ., 75 (France)

    1998-12-31

    This work shows up the usefulness of the Optically Stimulated Luminescence (OSL) to resolve radioprotection problems. We study the use of OSL as a gamma dosimetric technique with respect to the ALARA`s concept (As Low As Reasonably Achievable). A new approach based on optical fibers and luminescent materials showing OSL properties (closely related to Thermoluminescence phenomena) is presented in order to improve the remote real time dosimetry monitoring. Like thermoluminescent materials (TLD), OSL materials can trap charges under an irradiation (UV, X, {gamma},...). Instead of heating, the charges trapped are released by light stimulation and produce a visible luminescence which amount is proportional to trap the `data stored` left by irradiation, enabling the dose measurement. The OSL phenomenon offers the same advantages as TLD plus the interesting possibility of a remote optical stimulation. The end-user objective deals with the development of a {gamma}-radiation Optical FIber Sensor (OFS) for dose measurement which can offer new functionalities based on OSL materials coupled with an optical fiber. Rare earth doped Alkaline Earth Sulphides (AES), BAFX:EU{sup 2+} (X = Cl, Br, I) and halogen alkaline have been studied (crystalline form, synthesis techniques, influence of dopants and color centers). Their characteristics are presented and extensively discussed. A specific experimental set-up to characterise various OSL phosphors has been developed. It allows the study of sensitivity, linearity, time decay behaviour of OSL signal and zeroing time. A joint study of OSL and TL has shown the technical limitations as well as the thermal fading and the origin of the long zeroing time. An Optical Fiber Sensor (OFS) based on OSL and using MgS:Sm has been developed for practical applications on nuclear fields. Its specifications are presented and discussed, moreover improvements are proposed. (author) 320 refs.

  5. Investigating quartz optically stimulated luminescence dose-response curves at high doses

    Energy Technology Data Exchange (ETDEWEB)

    Lowick, Sally E., E-mail: lowick@geo.unibe.c [Institut fuer Geologie, Universitaet Bern, Baltzerstrasse 1-3, 3012 Bern (Switzerland); Preusser, Frank [Institut fuer Geologie, Universitaet Bern, Baltzerstrasse 1-3, 3012 Bern (Switzerland); Wintle, Ann G. [Institute of Geography and Earth Sciences, Aberystwyth University, AberystwythSY23 3DB (United Kingdom)

    2010-10-15

    Despite the general expectation that optically stimulated luminescence (OSL) growth should be described by a simple saturating exponential function, an additional high dose component is often reported in the dose response of quartz. Although often reported as linear, it appears that this response is the early expression of a second saturating exponential. While some studies using equivalent doses that fall in this high dose region have produced ages that correlate well with independent dating, others report that it results in unreliable age determinations. Two fine grain sedimentary quartz samples that display such a response were used to investigate the origin of this additional high dose component: three experiments were conducted to examine their dose-response up to >1000 Gy. The high dose rates provided by laboratory irradiation were found not to induce a sensitivity change in the response to a subsequent test dose, with the latter not being significantly different from those generated following naturally acquired doses. The relative percentage contributions of the fast and medium OSL components remained fixed throughout the dose-response curve, suggesting that the electron traps that give rise to the initial OSL do not change with dose. An attempt was made to investigate a change in luminescence centre recombination probability by monitoring the depletion of the '325 {sup o}C' thermoluminescence (TL) during the optical stimulation that would result in depletion of the OSL signal. The emissions measured through both the conventional ultraviolet (UV), and a longer wavelength violet/blue (VB) window, displayed similar relative growth with dose, although it was not possible to resolve the origin of the VB emissions. No evidence was found to indicate whether the additional component at high doses occurs naturally or is a product of laboratory treatment. However, it appears that these samples display an increased sensitivity of quartz OSL to high doses

  6. Thermally Stable White Emitting Eu(3+) Complex@Nanozeolite@Luminescent Glass Composite with High CRI for Organic-Resin-Free Warm White LEDs.

    Science.gov (United States)

    Zhang, Jinhui; Gong, Shuming; Yu, Jinbo; Li, Peng; Zhang, Xuejie; He, Yuwei; Zhou, Jianbang; Shi, Rui; Li, Huanrong; Peng, Aiyun; Wang, Jing

    2017-03-01

    Nowadays, it is still a great challenge for lanthanide complexes to be applied in solid state lighting, especially for high-power LEDs because they will suffer severe thermal-induced luminescence quenching and transmittance loss when LEDs are operated at high current. In this paper, we have not only obtained high efficient and thermally chemical stable red emitting hybrid material by introducing europium complex into nanozeolite (NZ) functionalized with the imidazolium-based stopper but also abated its thermal-induced transmittance loss and luminescence quenching behavior via coating it onto a heat-resistant luminescent glass (LG) with high thermal conductivity (1.07 W/mK). The results show that the intensity at 400 K for Eu(PPO)n-C4Si@NZ@LG remains 21.48% of the initial intensity at 300 K, which is virtually 153 and 13 times the intensity of Eu(PPO)3·2H2O and Eu(PPO)n-C4Si@NZ, respectively. Moreover, an organic-resin-free warm white LEDs device with a low CCT of 3994K, a high Ra of 90.2 and R9 of 57.9 was successfully fabricated simply by combining NUV-Chip-On-Board with a warm white emitting glass-film composite (i.e., yellowish-green emitting luminescent glass coated with red emitting hybrid film). Our method and results provide a feasible and promising way for lanthanide complexes to be used for general illumination in the future.

  7. Developments in luminescence measurement techniques

    DEFF Research Database (Denmark)

    Thomsen, Kristina Jørkov; Bøtter-Jensen, L.; Denby, Phil M.

    2006-01-01

    We report on our continuing investigation and development of new measurement facilities for use in irradiation, optical stimulation and luminescence signal detection; these facilities have potential application to all forms of luminescence-based retrospective dosimetry, and are particularly...... intended for use with the Riso TL/OSL reader. We have investigated the potential of new more powerful blue (455 nm) and green (530nm) LEDs, and of gated counting combined with pulsed stimulation light techniques using conventional LEDs. Measurement of time-resolved OSL has resulted in a method of real......; both types are very stable and reproducible. Other recent developments include the modification of a Riso reader to measure both thermally and optically stimulated electrons (TSE and OSE) from granular or chip phosphors. (c) 2006 Elsevier Ltd. All rights reserved....

  8. Optically stimulated luminescence of common plastic materials for accident dose reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Chang, I.; Lee, J. I.; Kim, J. L. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Chung, K. S. [Gyeongsang National Univ., Jinju (Korea, Republic of)

    2014-05-15

    Optically stimulate luminescence(OSL) has many applications in a variety of radiation dosimetry fields, including personal dosimetry, environmental radiation level monitor, retrospective dosimetry for dating, and reconstruction of radiation doses from radiation accident. In the reconstruction of radiation doses from radiation accident, OSL technique has been used to estimate the doses exposed to public area through analysis of housewares or house construing materials. Recently, many efforts have been carried out for dose reconstruction using personal electronic devices such as mobile phones and USB memory chips. Some of natural minerals such as quartz and feldspar have OSL properties. Quartz is the second most abundant mineral in continental crust of the Earth. In some of common plastics, inorganic fillers (quartz, alumina etc.) are added to make strengthen of their properties depends on applications areas. The aim of this research is to explore a possibility of use of the common plastic materials for dose reconstruction in radiation accident case. In this research the OSL dose response-curve and fading characteristics of the common plastics were tested and evaluated. Finally, we expect this work contribute to elevate the possibility of the dose reconstruction. The general conclusion of this work is that the possibility of dose reconstruction using common plastic materials is showed using the OSL characteristics of the materials. However, the tested common plastic materials have relatively low sensitivities. Further work is required to establish a database of OSL properties of common plastic materials for emergency dose reconstruction by using housewares.

  9. Monte Carlo simulation of an x-ray luminescence optical tomography scanner prototype

    Energy Technology Data Exchange (ETDEWEB)

    Rosas-González, S., E-mail: sarahi@fisica.unam.mx, E-mail: arnulfo@fisica.unam.mx; Martínez-Dávalos, A., E-mail: sarahi@fisica.unam.mx, E-mail: arnulfo@fisica.unam.mx; Rodríguez-Villafuerte, M., E-mail: sarahi@fisica.unam.mx, E-mail: arnulfo@fisica.unam.mx; Murrieta-Rodríguez, T., E-mail: sarahi@fisica.unam.mx, E-mail: arnulfo@fisica.unam.mx [Instituto de Física, Universidad Nacional Autónoma de México, A.P. 20-364, 01000 (Mexico)

    2014-11-07

    In this work we report the calculation of the deposited energy distribution produced by an x-ray luminescence optical tomography (XLOT) system in a phantom containing different concentrations of Gd{sub 2}O{sub 2}S:Eu nanoparticles. The calculations were performed via Monte Carlo simulation considering spectra from a W target x-ray tube operating between 30 and 90 kVp, with 1.0 mm Al added filtration. CT and XLOT tomographic images were reconstructed from the same data. The results show that XLOT has better detectability than CT alone, that the dose scales linearly with kVp for a fixed concentration of Gd{sub 2}O{sub 2}S:Eu and air-kerma rate, the scattered radiation contribution to the total dose and signal is about 20% and that the dose ratio for a 3 mm diameter insert containing 10 mg/ml Gd{sub 2}O{sub 2}S embedded in a 30 mm diameter water phantom is 6:1. This ratio drops to less than 2:1 for a 1 mg/ml concentration. Finally we show that the method of conjugate images can be used to correct for artifacts due to attenuation effects in XLOT images.

  10. Optically stimulated luminescence dating of archaeological ceramics from Osvaldo and Lago Grande sites in central Amazon

    Energy Technology Data Exchange (ETDEWEB)

    Hazenfratz, Roberto; Tudela, Diego R.G.; Munita, Casimiro S., E-mail: robertohm@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Mittani, Juan C.R.; Tatumi, Sonia H. [Universidade Federal de Sao Paulo (UNIFESP), Santos, SP (Brazil)

    2013-07-01

    Thermoluminescence (TL) and optically stimulated luminescence (OSL) dating are two important techniques for dating archaeological and geological material, especially suitable for archaeological ceramics, where samples for {sup 14}C dating are not available. In this work, five pottery shards from Osvaldo and Lago Grande archaeological sites were dated by OSL. For measurements, it was used the SAR protocol. The annual dose rates were estimated by the contents of U, Th and K, determined by instrumental neutron activation analysis (INAA) of the pottery shards and clay samples near both sites. Lago Grande and Osvaldo represent a microcosm of the region, and their proximity and high density of archaeological record turn them interesting to study possible relations of cultural and/or commercial exchange. Calculations showed that the water content is an important variable that cannot be neglected in OSL dating of pottery shards from central Amazon, due to the high humidity in regional soils. The results between 867 ± 101 and 1154 ± 62 years AD agreed with the average time span for the archaeological sites occupation found in the literature. (author)

  11. Insights on proximity effect and multiphoton induced luminescence from gold nanospheres in far field optical microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Borglin, Johan [Biomedical Photonics Group, Department of Chemistry and Molecular Biology, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Department of Physics, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Guldbrand, Stina [Department of Physics, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Evenbratt, Hanne [Pharmaceutical Technology, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 412 96 Gothenburg (Sweden); Kirejev, Vladimir; Ericson, Marica B., E-mail: marica.ericson@chem.gu.se [Biomedical Photonics Group, Department of Chemistry and Molecular Biology, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Grönbeck, Henrik [Department of Applied Physics, Chalmers University of Technology, Kemivägen 9, 412 96 Gothenburg (Sweden)

    2015-12-07

    Gold nanoparticles can be visualized in far-field multiphoton laser-scanning microscopy (MPM) based on the phenomena of multiphoton induced luminescence (MIL). This is of interest for biomedical applications, e.g., for cancer diagnostics, as MPM allows for working in the near-infrared (NIR) optical window of tissue. It is well known that the aggregation of particles causes a redshift of the plasmon resonance, but its implications for MIL applying far-field MPM should be further exploited. Here, we explore MIL from 10 nm gold nanospheres that are chemically deposited on glass substrates in controlled coverage gradients using MPM operating in NIR range. The substrates enable studies of MIL as a function of inter-particle distance and clustering. It was shown that MIL was only detected from areas on the substrates where the particle spacing was less than one particle diameter, or where the particles have aggregated. The results are interpreted in the context that the underlying physical phenomenon of MIL is a sequential two-photon absorption process, where the first event is driven by the plasmon resonance. It is evident that gold nanospheres in this size range have to be closely spaced or clustered to exhibit detectable MIL using far-field MPM operating in the NIR region.

  12. Optically stimulated luminescence (OSL) as a chronometer for surface exposure dating

    Science.gov (United States)

    Sohbati, Reza; Murray, Andrew S.; Chapot, Melissa S.; Jain, Mayank; Pederson, Joel

    2012-09-01

    We pioneer a technique of surface-exposure dating based upon the characteristic form of an optically stimulated luminescence (OSL) bleaching profile beneath a rock surface; this evolves as a function of depth and time. As a field illustration of this new method, the maximum age of a premier example of Barrier Canyon Style (BCS) rock art in Canyonlands National Park, Utah, USA, is constrained. The natural OSL signal from quartz grains is measured from the surface to a depth of >10 mm in three different rock samples of the Jurassic Navajo Sandstone. Two samples are from talus with unknown daylight exposure histories; one of these samples was exposed at the time of sampling and one was buried and no longer light exposed. A third sample is known to have been first exposed 80 years ago and was still exposed at the time of sampling. First, the OSL-depth profile of the known-age sample is modeled to estimate material-dependent and environmental parameters. These parameters are then used to fit the model to the corresponding data for the samples of unknown exposure history. From these fits we calculate that the buried sample was light exposed for ˜700 years before burial and that the unburied sample has been exposed for ˜120 years. The shielded surface of the buried talus sample is decorated with rock art; this rock fell from the adjacent Great Gallery panel. Related research using conventional OSL dating suggests that this rockfall event occurred ˜900 years ago, and so we deduce that the rock art must have been created between ˜1600 and 900 years ago. Our results are the first credible estimates of exposure ages based on luminescence bleaching profiles. The strength of this novel OSL method is its ability to establish both ongoing and prior exposure times, at decadal to millennial timescales or perhaps longer (depending on the environmental dose rate) even for material subsequently buried. This has considerable potential in many archeological, geological and geo

  13. KCl:Eu2+ as a solar UV-C radiation dosimeter.Optically stimulated luminescence and thermoluminescence analyses

    Institute of Scientific and Technical Information of China (English)

    I.Aguirre de Cáarcer; H.L.D'Antoni; M.Barboza-Flores; V.Correcher; F.Jaque

    2009-01-01

    The KCl:Eu2+ system response to UV-C was investigated by analyzing the optically stimulated luminescence (OSL) and thertoo-luminescence (TL) signal produced by ultraviolet light exposure at room temperature.It was found that after UV-C irradiation,OSL was produced on a wide band of visible wavelengths with decay time that varied by several orders of magnitude depending on the Eu2+ aggregation state.In spite of the low intensity of solar UV-C reaching the Earth's surface in Madrid (40° N,700 m a.s.l.),it was possible to measure the UV-C radiation dose at 6:48 solar time by using the TL response of the KCl:Eu2+ system and differentiate it from the ambient beta radiation dose.

  14. HIGH-STABLE ERBIUM SUPERLUMINESCENT FIBER OPTICAL SOURCES CREATION METHODS

    OpenAIRE

    A. S. Aleynik; N. E. Kikilich; V. N. Kozlov; A. A. Vlasov; NIKITENKO A.N.

    2016-01-01

    We present the overview of wideband Erbium doped superluminescent fiber sources (EDSFS) creation methods. This type of optical sources is mainly used in navigation accuracy class fiber-optical gyroscopes (FOG) production. For this application an optical source should have small coherence length to reduce FOG output signal error rate. Output signal errors are caused by different parasitic effects: reverse Rayleigh scattering, optical components mode swapping, Kerr effect. Consequently, the mos...

  15. An optically stimulated luminescence study of porcelain related to radiation dosimetry

    DEFF Research Database (Denmark)

    Poolton, N.R.J.; Bøtter-Jensen, L.; Jungner, H.

    1995-01-01

    This article describes the essential features regarding the photo-stimulated luminescence of porcelain: both the main ceramic and glazing materials are studied. In each case, radiation dose dependent signals are observed, superimposed on dose independent luminescence transitions that are both...... Stokes and anti-Stokes shifted in energy. Glazing is shown in some cases to be considerably more sensitive as a radiation dosemeter than the main porcelain ceramic. By comparison with the properties of artifical phosphors, the principal luminescent matrix is identified as being Al2O3...

  16. Effect of an electron beam irradiation on optical and luminescence properties of LiBaAlF6 single crystals

    Science.gov (United States)

    Ogorodnikov, I. N.; Pustovarov, V. A.; Omelkov, S. I.; Kirm, M.

    2017-07-01

    Paper reports the effect of a 10 keV, 110 keV and 10 MeV electron beam irradiation on optical and luminescence properties of LiBaAlF6 (LBAF) single crystals at 10, 90, and 293 K. Five absorption bands at 2.0, 3.2, 4.3, 4.9 and 5.5 eV were revealed in irradiated crystals in the energy range of 1.2-9.5 eV. Several PL emission bands (1.7-1.8, 2.2 and 2.5-3.5 eV) related to defects were found in the luminescence spectra at room temperature, while only one luminescence band at E = 2.2 eV appears at T = 90 K in LBAF crystals after a 10 MeV electron bombardment. The PL excitation spectra and time-response for these emission bands were studied at 10, 90, and 293 K. Thermoluminescence (TL) of irradiated crystals was studied in the temperature range of 90-740 K. New TL glow peaks at 166, 530 and 670 K were revealed and their parameters were determined. Temperature dependence of relative photoluminescence yield recorded monitoring emission at the 1.87 and 2.23 eV in the temperature range from 130 to 450 K, were fitted using five quenching processes related to TL glow peaks revealed in our research. Significant similarity in the manifestation of radiation-induced defects for LBAF and previously studied LiBaF3 single crystals is noted. The effect of an electron beam irradiation on optical and luminescence properties of LBAF single crystals and possible origin of the radiation defects were discussed.

  17. Depth dose deposition measurement in electronics packages using optically stimulated luminescence films; Mesure du rendement en profondeur dans un boitier de composant electronique au moyen de films luminescents stimulables optiquement

    Energy Technology Data Exchange (ETDEWEB)

    Ranchoux, G.; Dusseau, L.; Gensanne, D.; Plattard, D.; Polge, G.; Saigne, F.; Fesquet, J.; Gasiot, J. [Montpellier-2 Univ., CEMM2, 34 (France); Menduina, X. [Universite Autonome de Barcelone (Spain); Bessiere, J.C. [CORAD P.I.T. Pompignane, 34 - Montpelliers (France)

    1999-07-01

    The energy deposited by electrons versus depth inside molded Epoxy packages is measured using optically stimulated luminescence (OSL) dose mapping technique. Longitudinal and transversal depth dose curves are investigated under various angles of irradiation. Experimental results are compared with PENELOPE transport code calculations. Preliminary results are in good agreement with simulations.

  18. Configurational coordinate diagram of Ni{sup 2+} doped silver halide crystals, as determined by optical and luminescence measurements

    Energy Technology Data Exchange (ETDEWEB)

    Zakosky-Neuberger, I., E-mail: yifat_z2@hotmail.com [Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel); Shafir, I.; Nagli, L.; Katzir, A. [Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel)

    2012-08-15

    Optical and luminescence measurements were carried out on Ni{sup 2+} doped silver halide crystals. The configurational coordinates of the ground and the first excited states made it possible to explain the important optical properties, such as the Stokes shift between the ground and excited states, the broadening of the bands with temperature and the thermal quenching. Determining the configurational coordinate diagram of the ground and first excited states is the first step for the design and fabrication of solid state and fiber lasers which are based on Ni{sup 2+} doped silver halides and which operate in the middle infrared. - Highlights: Black-Right-Pointing-Pointer Optical and luminescence measurements were carried out on Ni{sup 2+} doped silver halide crystals. Black-Right-Pointing-Pointer Configurational coordinates of the ground and the first excited state were calculated. Black-Right-Pointing-Pointer Optical properties of Ni{sup 2+} doped silver halide crystals can be obtained from the configurational coordinate diagram. Black-Right-Pointing-Pointer No emission signal was found above 220 K.

  19. New Nanomaterials and Luminescent Optical Sensors for Detection of Hydrogen Peroxide

    OpenAIRE

    Natalia A. Burmistrova; Olga A. Kolontaeva; Axel Duerkop

    2015-01-01

    Accurate methods that can continuously detect low concentrations of hydrogen peroxide (H2O2) have a huge application potential in biological, pharmaceutical, clinical and environmental analysis. Luminescent probes and nanomaterials are used for fabrication of sensors for H2O2 that can be applied for these purposes. In contrast to previous reviews focusing on the chemical design of molecular probes for H2O2, this mini-review highlights the latest luminescent nanoparticular materials and new lu...

  20. Optically stimulated luminescence dating of aeolian sand in the otindag dune field and holocene climate change

    Science.gov (United States)

    Zhou, Y.L.; Lu, H.Y.; Mason, J.; Miao, X.D.; Swinehart, J.; Goble, R.

    2008-01-01

    The dune system in Otindag sand field of northern China is sensitive to climate change, where effective moisture and related vegetation cover play a controlling role for dune activity and stability. Therefore, aeolian deposits may be an archive of past environmental changes, possibly at the millennial scale, but previous studies on this topic have rarely been reported. In this study, thirty-five optically stimulated luminescence (OSL) ages of ten representative sand-paleosol profiles in Otindag sand field are obtained, and these ages provide a relatively complete and well-dated chronology for wet and dry variations in Holocene. The results indicate that widespread dune mobilization occurred from 9.9 to 8.2 ka, suggesting a dry early Holocene climate. The dunes were mainly stabilized between 8.0 and 2.7 ka, implying a relatively wet climate, although there were short-term penetrations of dune activity during this wet period. After ???2.3 ka, the region became dry again, as inferred from widespread dune activity. The "8.2 ka" cold event and the Little Ice Age climatic deterioration are detected on the basis of the dune records and OSL ages. During the Medieval Warm Period and the Sui-Tang Warm Period (570-770 AD), climate in Otindag sand field was relatively humid and the vegetation was denser, and the sand dunes were stabilized again. These aeolian records may indicate climate changes at millennial time scale during Holocene, and these climatic changes may be the teleconnection to the climate changes elsewhere in the world. ?? Science in China Press and Springer-Verlag GmbH 2008.

  1. Optically stimulated luminescence dating of aeolian sand in the Otindag dune field and Holocene climate change

    Institute of Scientific and Technical Information of China (English)

    Joseph; MASON; James; SWINEHART; Ronald; GOBLE

    2008-01-01

    The dune system in Otindag sand field of northern China is sensitive to climate change, where effective moisture and related vegetation cover play a controlling role for dune activity and stability. Therefore, aeolian deposits may be an archive of past environmental changes, possibly at the millennial scale, but previous studies on this topic have rarely been reported. In this study, thirty-five optically stimulated luminescence (OSL) ages of ten representative sand-paleosol profiles in Otindag sand field are ob-tained, and these ages provide a relatively complete and well-dated chronology for wet and dry varia-tions in Holocene. The results indicate that widespread dune mobilization occurred from 9.9 to 8.2 ka, suggesting a dry early Holocene climate. The dunes were mainly stabilized between 8.0 and 2.7 ka, implying a relatively wet climate, although there were short-term penetrations of dune activity during this wet period. After ~2.3 ka, the region became dry again, as inferred from widespread dune activity. The "8.2 ka" cold event and the Little Ice Age climatic deterioration are detected on the basis of the dune records and OSL ages. During the Medieval Warm Period and the Sui-Tang Warm Period (570-770 AD), climate in Otindag sand field was relatively humid and the vegetation was denser, and the sand dunes were stabilized again. These aeolian records may indicate climate changes at millennial time scale during Holocene, and these climatic changes may be the teleconnection to the climate changes elsewhere in the world.

  2. Optically stimulated luminescence dating of aeolian sand in the Otindag dune field and Holocene climate change

    Institute of Scientific and Technical Information of China (English)

    ZHOU YaLi; LU HuaYu; Joseph MASON; MIAO XiaoDong; James SWINEHART; Ronald GOBLE

    2008-01-01

    The dune system in Otindag sand field of northern China is sensitive to climate change, where effective moisture and related vegetation cover play a controlling role for dune activity and stability. Therefore, aeolian deposits may be an archive of past environmental changes, possibly at the millennial scale, but previous studies on this topic have rarely been reported. In this study, thirty-five optically stimulated luminescence (OSL) ages of ten representative sand-paleosol profiles in Otindag sand field are ob-tained, and these ages provide a relatively complete and well-dated chronology for wet and dry varia-tions in Holocene. The results indicate that widespread dune mobilization occurred from 9.9 to 8.2 ka, suggesting a dry early Holocene climate. The dunes were mainly stabilized between 8.0 and 2.7 ka, implying a relatively wet climate, although there were short-term penetrations of dune activity during this wet period. After ~2.3 ka, the region became dry again, as inferred from widespread dune activity. The "8.2 ka" cold event and the Little Ice Age climatic deterioration are detected on the basis of the dune records and OSL ages. During the Medieval Warm Period and the Sui-Tang Warm Period (570-770 AD), climate in Otindag sand field was relatively humid and the vegetation was denser, and the sand dunes were stabilized again. These aeolian records may indicate climate changes at millennial time scale during Holocene, and these climatic changes may be the teleconnection to the climate changes elsewhere in the world.

  3. Optically- and thermally-stimulated luminescences of Ce-doped SiO2 glasses prepared by spark plasma sintering

    Science.gov (United States)

    Okada, Go; Kasap, Safa; Yanagida, Takayuki

    2016-11-01

    Rare-earth doped phosphors have been used in many applications including radiation measurements. In the latter applications, the radiation photons are converted to light so that we can indirectly detect the radiation using a conventional photodetector. In this work, we have prepared and characterized a Ce-doped SiO2 glass for dosimeter applications. Unlike conventional techniques such as sol-gel synthesis, the sample was prepared by spark plasma sintering. Although the PL emission seems to be only from the Ce3+ ions in the structure, due to the X-ray induced luminescence, we have also observed optically-stimulated luminescence (OSL), and thermally-stimulated luminescence (TSL), owing to a pair of silylenes and a set of dioxasilirane and silylene in addition to Ce3+. We have measured the detector response vs irradiation dose for both the OSL and TSL. The detector response in both cases is linear over the dose range from at least 1 mGy to 2 Gy. Particularly, the sensitivity of TSL is so high that it should be considered to be a good candidate for practical applications.

  4. Highly luminescent and cytocompatible cationic Ag2S NIR-emitting quantum dots for optical imaging and gene transfection

    OpenAIRE

    Duman, Fatma Demir; Hocaoğlu, İbrahim; Hocaoglu, Ibrahim; Öztürk, Deniz Gülfem; Ozturk, Deniz Gulfem; Gözüaçık, Devrim; Gozuacik, Devrim; Kiraz, Alper; Yağcı Acar, Havva; Yagci Acar, Havva

    2015-01-01

    Nanoscale PAPER Cite this: Nanoscale, 2015, 7, 11352 Received 12th January 2015, Accepted 23rd May 2015 DOI: 10.1039/c5nr00189g www.rsc.org/nanoscale Highly luminescent and cytocompatible cationic Ag2S NIR-emitting quantum dots for optical imaging and gene transfection† Fatma Demir Duman,a Ibrahim Hocaoglu,a Deniz Gulfem Ozturk,b Devrim Gozuacik,b Alper Kiraza,c and Havva Yagci Acar*a,d,e The development of non-toxic theranostic nanoparticles capable of del...

  5. Optically stimulated luminescence sensitivity changes in quartz due to repeated use in single aliquot readout: Experiments and computer simulations

    DEFF Research Database (Denmark)

    McKeever, S.W.S.; Bøtter-Jensen, L.; Agersnap Larsen, N.

    1996-01-01

    As part of a study to examine sensitivity changes in single aliquot techniques using optically stimulated luminescence (OSL) a series of experiments has been conducted with single aliquots of natural quartz, and the data compared with the results of computer simulations of the type of processes...... believed to be occurring. The computer model used includes both shallow and deep ('hard-to-bleach') traps, OSL ('easy-to-bleach') traps, and radiative and non-radiative recombination centres. The model has previously been used successfully to account for sensitivity changes in quartz due to thermal...... trap and deep trap effects....

  6. The manifestation of optical centers in UV-Vis absorption and luminescence spectra of white blood human cells

    Science.gov (United States)

    Terent'yeva, Yu G.; Yashchuk, V. M.; Zaika, L. A.; Snitserova, O. M.; Losytsky, M. Yu

    2016-12-01

    A white blood human cells spectral investigation is presented. The aim of this series of experiments was to obtain and analyze the absorption and luminescence (fluorescence and phosphorescence) spectra at room temperature and at 78 K of newly isolated white blood human cells and their organelles. As a result the optical centers and possible biochemical components that form the studied spectra where identified. Also the differences between the spectra of abnormal cells (B-cell chronic lymphocytic leukemia BCLL) and normal ones were studied for the whole cells and individual organelles.

  7. Thermally and optically stimulated luminescence of AlN-Y2O3 ceramics after ionising irradiation

    DEFF Research Database (Denmark)

    Trinkler, L.; Bos, A.J.J.; Winkelman, A.J.M.;

    1999-01-01

    Thermally (TL) and optically stimulated luminescence (OSL) were studied in AlN-Y2O3 ceramics after irradiation with ionising radiation. The extremely high TL sensitivity (approximately 60 times the sensitivity of LiF:Mg,Tl (TLD-100)) makes AlN-Y2O3 ceramics attractive as a TLD material. However......, an essential drawback of AlN-Y2O3 is its high fading rate. Special attention has been focused on understanding and improving the fading properties. In particular, the influence of the ceramics production conditions and the additive concentration on the fading rate have been studied. Experimental results...

  8. Use of scanning near-field optical microscope with an aperture probe for detection of luminescent nanodiamonds

    Science.gov (United States)

    Shershulin, V. A.; Samoylenko, S. R.; Shenderova, O. A.; Konov, V. I.; Vlasov, I. I.

    2017-02-01

    The suitability of scanning near-field optical microscopy (SNOM) to image photoluminescent diamond nanoparticles with nanoscale resolution is demonstrated. Isolated diamond nanocrystals with an average size of 100 nm, containing negatively charged nitrogen-vacancy (NV-) centers, were chosen as tested material. The NV- luminescence was stimulated by continuous 532 nm laser light. Sizes of analyzed crystallites were monitored by an atomic force microscope. The lateral resolution of the order of 100 nm was reached in SNOM imaging of diamond nanoparticles using 150 nm square aperture of the probe.

  9. HIGH-STABLE ERBIUM SUPERLUMINESCENT FIBER OPTICAL SOURCES CREATION METHODS

    Directory of Open Access Journals (Sweden)

    A. S. Aleynik

    2016-07-01

    Full Text Available We present the overview of wideband Erbium doped superluminescent fiber sources (EDSFS creation methods. This type of optical sources is mainly used in navigation accuracy class fiber-optical gyroscopes (FOG production. For this application an optical source should have small coherence length to reduce FOG output signal error rate. Output signal errors are caused by different parasitic effects: reverse Rayleigh scattering, optical components mode swapping, Kerr effect. Consequently, the most important characteristics of EDSFS are central wavelength time and wide temperature range stability and optical spectrum width and shape. The spectrum shape is needed to be close to the Gaussian distribution to minimize time coherence function. The paper deals with major EDSFS instability reasons and their most effective spectral parameters stabilization and optimization methods. We consider various methods of output optical radiation spectrum correction, and problems connected with output radiation residual polarization, the EDSFS principle of operation, structure and their basic construction schemes, the overview of Erbium-doped active fibers for EDSFS creation. The conclusions on most effective output optical radiation stabilization methods are drawn.

  10. Ultra-stable long distance optical frequency distribution using the Internet fiber network

    CERN Document Server

    Lopez, Olivier; Chanteau, Bruno; Chardonnet, Christian; Amy-Klein, Anne; Santarelli, Georgio

    2012-01-01

    We report an optical link of 540 km for ultrastable frequency distribution over the Internet fiber network. The stable frequency optical signal is processed enabling uninterrupted propagation on both directions. The robustness and the performance of the link are enhanced by a cost effective fully automated optoelectronic station. This device is able to coherently regenerate the return optical signal with a heterodyne optical phase locking of a low noise laser diode. Moreover the incoming signal polarization variation are tracked and processed in order to maintain beat note amplitudes within the operation range. Stable fibered optical interferometer enables optical detection of the link round trip phase signal. The phase-noise compensated link shows a fractional frequency instability in 10 Hz bandwidth of 5\\times10-15 at one second measurement time and 2\\times10-19 at 30 000 s. This work is a significant step towards a sustainable wide area ultrastable optical frequency distribution and comparison network.

  11. Optically stimulated phosphorescence in quartz over the millisecond to second time scale: insights into the role of shallow traps in delaying luminescent recombination

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Jain, Mayank

    2010-01-01

    Time-resolved optically stimulated luminescence (TR-OSL) curves from quartz are usually measured over a few hundred microseconds because this time range best illustrates the main component in quartz which lies in the range 30–45 µs. In this study we present the decay form of quartz TR-OSL and opt......Time-resolved optically stimulated luminescence (TR-OSL) curves from quartz are usually measured over a few hundred microseconds because this time range best illustrates the main component in quartz which lies in the range 30–45 µs. In this study we present the decay form of quartz TR...

  12. Recent developments of optically stimulated luminescence materials and techniques for radiation dosimetry and clinical applications

    Directory of Open Access Journals (Sweden)

    Pradhan A

    2008-01-01

    Full Text Available During the last 10 years, optically stimulated luminescence (OSL has emerged as a formidable competitor not only to thermoluminescence dosimetry (TLD but also to several other dosimetry systems. Though a large number of materials have been synthesized and studied for OSL, Al 2 O 3 :C continues to dominate the dosimetric applications. Re-investigations of OSL in BeOindicate that this material might provide an alternative to Al 2 O 3 :C. Study of OSL of electronic components of mobile phones and ID cards appears to have opened up a feasibility of dosimetry and dose reconstruction using the electronic components of gadgets of everyday use in the events of unforeseen situations of radiological accidents, including the event of a dirty bomb by terrorist groups. Among the newly reported materials, a very recent development of NaMgF 3 :Eu 2+ appears fascinating because of its high OSL sensitivity and tolerable tissue equivalence. In clinical dosimetry, an OSL as a passive dosimeter could do all that TLD can do, much faster with a better or at least the same efficiency; and in addition, it provides a possibility of repeated readout unlike TLD, in which all the dose information is lost in a single readout. Of late, OSL has also emerged as a practical real-time dosimeter for in vivo measurements in radiation therapy (for both external beams and brachytherapy and in various diagnostic radiological examinations including mammography and CT dosimetry. For in vivo measurements, a probe of Al 2 O 3 :C of size of a fraction of a millimeter provides the information on both the dose rate and the total dose from the readout of radioluminescence and OSL signals respectively, from the same probe. The availability of OSL dosimeters in various sizes and shapes and their performance characteristics as compared to established dosimeters such as plastic scintillation dosimeters, diode detectors, MOSFET detectors, radiochromic films, etc., shows that OSL may soon become

  13. A methodology for on-board CBCT imaging dose using optically stimulated luminescence detectors.

    Science.gov (United States)

    Mail, Noor; Yusuf, Muhammad; Alothmany, Nazeeh; Kinsara, A Abdulrahman; Abdulkhaliq, Fahad; Ghamdi, Suliman M; Saoudi, Abdelhamid

    2016-09-08

    Cone-beam computed tomography CBCT systems are used in radiation therapy for patient alignment and positioning. The CBCT imaging procedure for patient setup adds substantial radiation dose to patient's normal tissue. This study pre-sents a complete procedure for the CBCT dosimetry using the InLight optically-stimulated-luminescence (OSL) nanoDots. We report five dose parameters: the mean slice dose (DMSD); the cone beam dose index (CBDIW); the mean volume dose (DMVD); point-dose profile, D(FOV); and the off-field Dose. In addition, CBCT skin doses for seven pelvic tumor patients are reported. CBCT-dose mea-surement was performed on a custom-made cylindrical acrylic body phantom (50cm length, 32cm diameter). We machined 25 circular disks (2 cm thick) with grooves and holes to hold OSL-nanoDots. OSLs that showed similar sensitivities were selected and calibrated against a Farmer-type ionization-chamber (0.6 CT) before being inserted into the grooves and holes. For the phantom scan, a standard CBCT-imaging protocol (pelvic sites: 125 kVp, 80 mA and 25 ms) was used. Five dose parameters were quantified: DMSD, CBDIW, DMVD, D(FOV), and the off-field dose. The DMSD for the central slice was 31.1 ± 0.85 mGy, and CBDIW was 34.5± 0.6 mGy at 16cm FOV. The DMVD was 25.6 ± 1.1 mGy. The off-field dose was 10.5 mGy. For patients, the anterior and lateral skin doses attributable to CBCT imaging were 39.04 ± 4.4 and 27.1 ± 1.3 mGy, respectively.OSL nanoDots were convenient to use in measuring CBCT dose. The method of selecting the nanoDots greatly reduced uncertainty in the OSL measurements. Our detailed calibration procedure and CBCT dose measurements and calculations could prove useful in developing OSL routines for CBCT quality assessment, which in turn gives them the property of high spatial resolution, meaning that they have the potential for measurement of dose in regions of severe dose-gradients.

  14. Energy dependence and angular dependence of an optically stimulated luminescence dosimeter in the mammography energy range.

    Science.gov (United States)

    Kawaguchi, Ai; Matsunaga, Yuta; Suzuki, Shoichi; Chida, Koichi

    2017-03-01

    This study aimed to investigate the energy dependence and the angular dependence of commercially available optically stimulated luminescence (OSL) point dosimeters in the mammography energy range. The energy dependence was evaluated to calculate calibration factors (CFs). The half-value layer range was 0.31-0.60 mmAl (Mo/Mo 22-28 kV, Mo/Rh 28-32 kV, and W/Rh 30-34 kV at 2-kV intervals). Mo/Rh 28 kV was the reference condition. Angular dependence was tested by rotating the X-ray tube from -90° to 90° in 30° increments, and signal counts from angled nanoDots were normalized to the 0° signal counts. Angular dependence was compared with three tube voltage and target/filter combinations (Mo/Mo 26 kV, Mo/Rh 28 kV and W/Rh 32 kV). The CFs of energy dependence were 0.94-1.06. In Mo/Mo 26-28 kV and Mo/Rh 28-32 kV, the range of CF was 0.99-1.01, which was very similar. For angular dependence, the most deteriorated normalized values (Mo/Mo, 0.37; Mo/Rh, 0.43; and W/Rh, 0.58) were observed when the X-ray tube was rotated at a 90° angle, compared to 0°. The most angular dependences of ± 30°, 60°, and 90° decreased by approximately 4%, 14%, and 63% respectively. The mean deteriorated measurement 30° intervals from 0° to ± 30° was 2%, from ± 30° to ± 60° was 8%, and from ± 60° to ± 90° was 40%. The range of energy dependence in typical mammography energy range was not as much as that in general radiography and computed tomography. For accurate measurement using nanoDot, the tilt needs to be under 30°.

  15. Stable phantom materials for ultrasound and optical imaging

    Science.gov (United States)

    Cabrelli, Luciana C.; Pelissari, Pedro I. B. G. B.; Deana, Alessandro M.; Carneiro, Antonio A. O.; Pavan, Theo Z.

    2017-01-01

    Phantoms mimicking the specific properties of biological tissues are essential to fully characterize medical devices. Water-based materials are commonly used to manufacture phantoms for ultrasound and optical imaging techniques. However, these materials have disadvantages, such as easy degradation and low temporal stability. In this study, we propose an oil-based new tissue-mimicking material for ultrasound and optical imaging, with the advantage of presenting low temporal degradation. A styrene-ethylene/butylene-styrene (SEBS) copolymer in mineral oil samples was made varying the SEBS concentration between 5%-15%, and low-density polyethylene (LDPE) between 0%-9%. Acoustic properties, such as the speed of sound and the attenuation coefficient, were obtained using frequencies ranging from 1-10 MHz, and were consistent with that of soft tissues. These properties were controlled varying SEBS and LDPE concentration. To characterize the optical properties of the samples, the diffuse reflectance and transmittance were measured. Scattering and absorption coefficients ranging from 400 nm-1200 nm were calculated for each compound. SEBS gels are a translucent material presenting low optical absorption and scattering coefficients in the visible region of the spectrum, but the presence of LDPE increased the turbidity. Adding LDPE increased the absorption and scattering of the phantom materials. Ultrasound and photoacoustic images of a heterogeneous phantom made of LDPE/SEBS containing a spherical inclusion were obtained. Annatto dye was added to the inclusion to enhance the optical absorbance. The results suggest that copolymer gels are promising for ultrasound and optical imaging, making them also potentially useful for photoacoustic imaging.

  16. Comparative analysis of luminescent properties of germanate glass and double-clad optical fibers co-doped with Yb3+/Ho3+ ions

    Science.gov (United States)

    Pietrzycki, Marcin; Kochanowicz, Marcin; Romańczuk, Patryk; Żmojda, Jacek; Miluski, Piotr; Ragiń, Tomasz; Jeleń, Piotr; Sitarz, Maciej; Dorosz, Dominik

    2016-09-01

    The 2 μm and visible emission of low phonon (805 cm-1) germanate glasses and double - clad optical fiber co-doped with 0.7Yb2O3/(0.07-0.7)Ho2O3 ions have been investigated. Luminescence at 2 μm corresponding to Ho3+: 5I7 → 5I8 as well as upconversion luminescence in the visible spectral range corresponding to the Ho3+: 5S2(5F4)→5I8 (545 nm), and Ho3+: 5F5→5I8 (655 nm) transition, respectively were obtained. The optimization of the acceptor content and donor-acceptor ratio were conducted with the purpose of maximizing the luminescence intensity. The highest luminescence intensity in both spectral range was obtained in glass co-doped with 0.7Yb2O3/0.15 Ho2O3. Despite relatively small effective absorption coefficient of the optical fiber comparative analysis of luminescent properties of fabricated glasses (further core) and double - clad optical fiber showed significant contribution of reabsorption process of emitted ASE signal.

  17. Optically stimulated luminescence (OSL) of Lu{sub 2}SiO{sub 5}:Ce powder: A preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Gartia, R.K., E-mail: rkgartia02@yahoo.i [Physics Department, Manipur University, Imphal 795003 (India); Singh, Th. Tejkumar [Physics Department, Manipur University, Imphal 795003 (India); Singh, Th. Basanta [Luminescence Dating Laboratory, Manipur University, Imphal 795003 (India)

    2011-01-01

    Optically stimulated luminescence (OSL) of Lu{sub 2}SiO{sub 5}:Ce powder (Phosphor Technology Ltd., UK) has been measured by Riso TL/OSL Reader (TL-DA-15). Upon blue photon stimulation ({lambda}{sub ex} {approx}470 nm) the material shows strong OSL signal that can detect {beta}-irradiation right up to the dose of {approx}0.2 Gy. A brief discussion on this finding is presented by comparing the thermoluminescence of the system with and without optical stimulation. The two key important parameters namely, trap-depth (E) and frequency factor (s) of the main peaks that occur at 85 and 232 {sup o}C are determined.

  18. Stable Second-Order Nonlinear Optical Materials Based on Interpenetrating Polymer Networks

    Science.gov (United States)

    1994-03-17

    0IJUN93 to 31MAY94 4. 1I1Lk ANDLSUBI1ILIE D. ?-UNUING NUMBERS •’• Stable Second-Order Nonlinear Optical Materials Based On C:N00014-90-J-1148...release and sale; its distribution is unlimited. I Stable Second-Order Nonlinear Optical Materials Based On Interpenetrating Polymer Networks S... Optical Materials Based On Interpenetrating Polymer Networks by S. Marturunkakul, J. I. Chen, L. Li, X. L. Jiang, R. J. Jeng, S. K. Sengupta, J. Kumar

  19. Internal luminescence efficiencies in InGaP/GaAs/Ge triple-junction solar cells evaluated from photoluminescence through optical coupling between subcells

    Science.gov (United States)

    Tex, David M.; Imaizumi, Mitsuru; Akiyama, Hidefumi; Kanemitsu, Yoshihiko

    2016-12-01

    In-situ characterization is one of the most powerful techniques to improve material quality and device performance. Especially in view of highly efficient tandem solar cells this is an important issue for improving the cost-performance ratio. Optical techniques are suitable characterization methods, since they are non-destructing and contactless. In this work, we measured the power dependence of photoluminescence (PL) from the InGaP and GaAs subcells of an industry-standard triple-junction solar cell. High luminescence yields enhance the luminescence coupling, which was directly verified by time-resolved PL measurements. We present a new method to determine the internal luminescence efficiencies of InGaP and GaAs subcells with the aid of luminescence coupling. High luminescence efficiencies of 90% for GaAs and more than 20% for InGaP were found, which suggest that the material quality of the grown GaAs layer is excellent while the intrinsic luminescence limit of InGaP is still not reached even for high excitation conditions. The PL method is useful for probing the intrinsic material properties of the subcells in flat band condition, without influence of transport. Since no calibration of absolute PL is required, a fast screening of the material quality is possible, which should be extremely helpful for the solar cell industry.

  20. An assessment of cumulative external doses from Chernobyl fallout for a forested area in Russia using the optically stimulated luminescence from quartz inclusions in bricks

    DEFF Research Database (Denmark)

    Ramzaev, V.; Bøtter-Jensen, Lars; Thomsen, Kristina Jørkov

    2008-01-01

    Optically stimulated luminescence (OSL) has been used for estimation of the accumulated doses in quartz inclusions obtained from two fired bricks, extracted in July 2004 from a building located in the forested surroundings of the recreational area Novie Bobovichi, the Bryansk Region, Russia...

  1. Thermoluminescence, luminescence optically stimulated and creation of defects in alkaline halogenides contaminated with Europium; Termoluminiscencia, luminiscencia opticamente estimulada y creacion de defectos en halogenuros alcalinos contaminados con Europio

    Energy Technology Data Exchange (ETDEWEB)

    Barboza F, M. [Centro de Investigacion en Fisica, Universidad de Sonora, Apartado Postal 5-088, 83190 Hermosillo, Sonora (Mexico)

    1999-07-01

    The alkaline halogenides have been subject matter of investigations related with the search of sensor materials for X-ray bidimensional images or optical memories. The understanding of the damage formation processes generated by ionizing and non-ionizing radiations is important for the correct design of devices that working as detectors and dosemeters of both type of radiations. In this work we present the investigation results related with the defects produced by the ionizing radiation type X and ultraviolet light in the range of 200-360 nm in crystals of KCl: Eu{sup 2+} and KBr:Eu{sup 2+}. It is examined the thermoluminescence and luminescence spectra with the purpose of identifying the exciton processes, owing to the excitation of the halogenide ions in which the primary defects correspond to the F and H centers. It has been found that the 400-600 nm emission is associated with the luminescence type that in his turn can be associated with autotrapped excitons perturbed by the impurity. On the other hand, it is examined the emission spectra of the luminescence optically stimulated in crystals of KBr: Eu{sup 2+} and KCl: Eu{sup 2+} finding too that such materials would be used as optical memories susceptible of to store information, and through of photostimulation to read this. It was determined that the F centers participate in the luminescence optically stimulated in these crystals, as well as too in the recombination processes responsible by the thermoluminescent emission. (Author)

  2. Optical and luminescence studies of ZnMoO 4 using vacuum ultraviolet synchrotron radiation

    Science.gov (United States)

    Mikhailik, V. B.; Kraus, H.; Wahl, D.; Ehrenberg, H.; Mykhaylyk, M. S.

    2006-06-01

    In this paper we present a characterisation of ZnMoO 4 using spectroscopic techniques. Reflection, luminescence and luminescence excitation spectra were measured over the temperature range 8-295 K using VUV synchrotron radiation. The emission spectrum of the crystal exhibits a broad band with a maximum around 1.95 eV at 80 K that is attributed to the radiative transitions within MO 42- oxyanion complex. An interpretation of the observed features of the electronic excitations in the crystal is given based on present knowledge of the electronic structure and emission properties of molybdate crystals. The results of this study suggest that ZnMoO 4 is a suitable candidate for further testing for implementation as a target material in cryogenic scintillation searches for rare events.

  3. Optical and luminescence studies of ZnMoO{sub 4} using vacuum ultraviolet synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Mikhailik, V.B. [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom)]. E-mail: vmikhai@hotmail.com; Kraus, H. [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Wahl, D. [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Ehrenberg, H. [Material Science, Darmstadt University of Technology, Petersenstr. 23, Darmstadt 64287 (Germany); Mykhaylyk, M.S. [Physics Department, Lviv National University, 8 Kyryla and Mefodiya str., Lviv, 79005 (Ukraine)

    2006-06-15

    In this paper we present a characterisation of ZnMoO{sub 4} using spectroscopic techniques. Reflection, luminescence and luminescence excitation spectra were measured over the temperature range 8-295 K using VUV synchrotron radiation. The emission spectrum of the crystal exhibits a broad band with a maximum around 1.95 eV at 80 K that is attributed to the radiative transitions within MO{sub 4} {sup 2-} oxyanion complex. An interpretation of the observed features of the electronic excitations in the crystal is given based on present knowledge of the electronic structure and emission properties of molybdate crystals. The results of this study suggest that ZnMoO{sub 4} is a suitable candidate for further testing for implementation as a target material in cryogenic scintillation searches for rare events.

  4. X-ray absorption fine structure and X-ray excited optical luminescence studies of II-VI semiconducting nanostructures

    Science.gov (United States)

    Murphy, Michael Wayne

    2010-06-01

    Various II-VI semiconducting nanomaterials such as ZnO-ZnS nanoribbons (NRs), CdSxSe1-x nanostructures, ZnS:Mn NRs, ZnS:Mn,Eu nanoprsims (NPs), ZnO:Mn nanopowders, and ZnO:Co nanopowders were synthesized for study. These materials were characterized by techniques such as scanning electron microscopy, transmission electron microscopy, element dispersive X-ray spectroscopy, selected area electron diffraction, and X-ray diffraction. The electronic and optical properties of these nanomaterials were studied by X-ray absorption fine structure (XAFS) spectroscopy and X-ray excited optical luminescence (XEOL) techniques, using tuneable soft X-rays from a synchrotron light source. The complementary nature ofthe XAFS and XEOL techniques give site, element and chemical specific measurements which allow a better understanding of the interplay and role of each element in the system. Chemical vapour deposition (CVD) of ZnS powder in a limited oxygen environment resulted in side-by-side biaxial ZnO-ZnS NR heterostructures. The resulting NRs contained distinct wurtzite ZnS and wurtzite ZnO components with widths of 10--100 nm and 20 --500 nm, respectively and a uniform interface region of 5-15 nm. XAFS and XEOL measurements revealed the luminescence of ZnO-ZnS NRs is from the ZnO component. The luminescence of CdSxSe1-x nanostructures is shown to be dependent on the S to Se ratio, with the band-gap emission being tunable between that of pure CdS and CdSe. Excitation of the CdSxSe 1-x nanostructures by X-ray in XEOL has revealed new de-excitation channels which show a defect emission band not seen by laser excitation. CVD of Mn2+ doped ZnS results in nanostructures with luminescence dominated by the yellow Mn2+ emission due to energy transfer from the ZnS host to the Mn dopant sites. The addition of EuCl3 to the reactants in the CVD process results in a change in morphology from NR to NP. Zn1-xMnxO and Zn1-xCOxO nanopowders were prepared by sol-gel methods at dopant concentrations

  5. Making optical atomic clocks more stable with $10^{-16}$ level laser stabilization

    CERN Document Server

    Jiang, Y Y; Lemke, N D; Fox, R W; Sherman, J A; Ma, L -S; Oates, C W

    2011-01-01

    The superb precision of an atomic clock is derived from its stability. Atomic clocks based on optical (rather than microwave) frequencies are attractive because of their potential for high stability, which scales with operational frequency. Nevertheless, optical clocks have not yet realized this vast potential, due in large part to limitations of the laser used to excite the atomic resonance. To address this problem, we demonstrate a cavity-stabilized laser system with a reduced thermal noise floor, exhibiting a fractional frequency instability of $2 \\times 10^{-16}$. We use this laser as a stable optical source in a Yb optical lattice clock to resolve an ultranarrow 1 Hz transition linewidth. With the stable laser source and the signal to noise ratio (S/N) afforded by the Yb optical clock, we dramatically reduce key stability limitations of the clock, and make measurements consistent with a clock instability of $5 \\times 10^{-16} / \\sqrt{\\tau}$.

  6. Multicolour optical coding from a series of luminescent lanthanide complexes with a unique antenna.

    Science.gov (United States)

    Wartenberg, Nicolas; Raccurt, Olivier; Bourgeat-Lami, Elodie; Imbert, Daniel; Mazzanti, Marinella

    2013-03-04

    The bis-tetrazolate-pyridine ligand H(2)pytz sensitises efficiently the visible and/or near-IR luminescence emission of ten lanthanide cations (Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb). The Ln(III) complexes present sizeable quantum yields in both domains with a single excitation source. The wide range of possible colour combinations in water, organic solvents and the solid state makes the complexes very attractive for labelling and encoding.

  7. Application of the optically stimulated luminescence (OSL) technique for mouse dosimetry in micro-CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Vrigneaud, Jean-Marc; Courteau, Alan; Oudot, Alexandra; Collin, Bertrand [Department of Nuclear Medicine, Centre Georges-François Leclerc, 1 rue Professeur Marion, Dijon 21079 Cedex (France); Ranouil, Julien [Landauer Europe, 33 avenue du Général Leclerc, Fontenay-aux-Roses 92266 Cedex (France); Morgand, Loïc; Raguin, Olivier [Oncodesign, 20 rue Jean Mazen, Dijon 21076 Cedex (France); Walker, Paul [LE2i CNRS UMR 5158, Faculty of Medicine, BP 87900, 21079 Dijon Cedex (France); Brunotte, François [Department of Nuclear Medicine, Centre Georges-François Leclerc, 1 rue Professeur Marion, Dijon 21079 Cedex, France and LE2i CNRS UMR 5158, Faculty of Medicine, BP 87900, 21079 Dijon Cedex (France)

    2013-12-15

    Purpose: Micro-CT is considered to be a powerful tool to investigate various models of disease on anesthetized animals. In longitudinal studies, the radiation dose delivered by the micro-CT to the same animal is a major concern as it could potentially induce spurious effects in experimental results. Optically stimulated luminescence dosimeters (OSLDs) are a relatively new kind of detector used in radiation dosimetry for medical applications. The aim of this work was to assess the dose delivered by the CT component of a micro-SPECT (single-photon emission computed tomography)/CT camera during a typical whole-body mouse study, using commercially available OSLDs based on Al{sub 2}O{sub 3}:C crystals.Methods: CTDI (computed tomography dose index) was measured in micro-CT with a properly calibrated pencil ionization chamber using a rat-like phantom (60 mm in diameter) and a mouse-like phantom (30 mm in diameter). OSLDs were checked for reproducibility and linearity in the range of doses delivered by the micro-CT. Dose measurements obtained with OSLDs were compared to those of the ionization chamber to correct for the radiation quality dependence of OSLDs in the low-kV range. Doses to tissue were then investigated in phantoms and cadavers. A 30 mm diameter phantom, specifically designed to insert OSLDs, was used to assess radiation dose over a typical whole-body mouse imaging study. Eighteen healthy female BALB/c mice weighing 27.1 ± 0.8 g (1 SD) were euthanized for small animal measurements. OLSDs were placed externally or implanted internally in nine different locations by an experienced animal technician. Five commonly used micro-CT protocols were investigated.Results: CTDI measurements were between 78.0 ± 2.1 and 110.7 ± 3.0 mGy for the rat-like phantom and between 169.3 ± 4.6 and 203.6 ± 5.5 mGy for the mouse-like phantom. On average, the displayed CTDI at the operator console was underestimated by 1.19 for the rat-like phantom and 2.36 for the mouse

  8. Serum-stable quantum dot--protein hybrid nanocapsules for optical bio-imaging

    Science.gov (United States)

    Lee, Jeong Yu; Nam, Dong Heon; Oh, Mi Hwa; Kim, Youngsun; Choi, Hyung Seok; Jeon, Duk Young; Beum Park, Chan; Nam, Yoon Sung

    2014-05-01

    We introduce shell cross-linked protein/quantum dot (QD) hybrid nanocapsules as a serum-stable systemic delivery nanocarrier for tumor-targeted in vivo bio-imaging applications. Highly luminescent, heavy-metal-free Cu0.3InS2/ZnS (CIS/ZnS) core-shell QDs are synthesized and mixed with amine-reactive six-armed poly(ethylene glycol) (PEG) in dichloromethane. Emulsification in an aqueous solution containing human serum albumin (HSA) results in shell cross-linked nanocapsules incorporating CIS/ZnS QDs, exhibiting high luminescence and excellent dispersion stability in a serum-containing medium. Folic acid is introduced as a tumor-targeting ligand. The feasibility of tumor-targeted in vivo bio-imaging is demonstrated by measuring the fluorescence intensity of several major organs and tumor tissue after an intravenous tail vein injection of the nanocapsules into nude mice. The cytotoxicity of the QD-loaded HSA-PEG nanocapsules is also examined in several types of cells. Our results show that the cellular uptake of the QDs is critical for cytotoxicity. Moreover, a significantly lower level of cell death is observed in the CIS/ZnS QDs compared to nanocapsules loaded with cadmium-based QDs. This study suggests that the systemic tumor targeting of heavy-metal-free QDs using shell cross-linked HSA-PEG hybrid nanocapsules is a promising route for in vivo tumor diagnosis with reduced non-specific toxicity.

  9. Development of optically stimulated luminescence techniques using natural minerals and ceramics, and their application to retrospective dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Boetter-Jensen, L

    2000-09-01

    This thesis summarises research and development of optically stimulated luminescence (OSL) and its applications by the author at Risoe National Laboratory, up to 1999. These developments have been directed primarily at retrospective accident dosimetry and luminescence dating. Experimental investigations include the studies of OSL properties of the natural minerals quartz and feldspars and the artificial materials porcelain and aluminium oxide (Al{sub 2}O{sub 3}). Blue light emitting diodes and infrared laser diodes are shown to provide simple and practical alternatives to broad-band light and visible laser stimulation. The development of OSL apparatus designed for the rapid measurement of single grains of phosphors also opens up a new area of luminescence measurement, allowing the detailed examination of dose distributions within a multiple-grain sample. This is of particular importance to the studies of incompletely reset geological sediments, and to accident dosimetry measurements using unheated materials. Al{sub 2}O{sub 3}:C single crystals are tested as environmental OSL dosemeters for assessing both the natural background photon radiation dose rates in the field and the natural dose rates inside bricks collected for accident dose evaluation. Environmental doses of the order of few {mu}Gy are measured with high precision. UV photo-stimulated luminescence spectra obtained from porcelain samples are used to confirm that the main component responsible for the OSL signal from porcelain is Al{sub 2}O{sub 3}. OSL single-aliquot regenerative-dose (SAR) techniques are used with quartz extracted from Chernobyl bricks to determine the accrued dose after the accident. This has improved the measurement precision significantly, from about 5-6 % using traditional methods to now less than 2 %. Depth-dose profiles measured in Chernobyl bricks are compared with those obtained in the laboratory using different gamma sources and these comparisons show that the average energy of

  10. Improved properties of phosphor-filled luminescent down-shifting layers: reduced scattering, optical model, and optimization for PV application

    Science.gov (United States)

    Solodovnyk, Anastasiia; Lipovšek, Benjamin; Forberich, Karen; Stern, Edda; Krč, Janez; Batentschuk, Miroslaw; Topič, Marko; Brabec, Christoph J.

    2015-12-01

    We studied the optical properties of polymer layers filled with phosphor particles in two aspects. First, we used two different polymer binders with refractive indices n = 1.46 and n = 1.61 (λ = 600 nm) to decrease Δn with the phosphor particles (n = 1.81). Second, we prepared two particle size distributions D50 = 12 μm and D50 = 19 μm. The particles were dispersed in both polymer binders in several volume concentrations and coated onto glass with thicknesses of 150 - 600 μm. We present further a newly developed optical model for simulation and optimization of such luminescent down-shifting (LDS) layers. The model is developed within the ray tracing framework of the existing optical simulator CROWM (Combined Ray Optics / Wave Optics Model), which enables simulation of standalone LDS layers as well as complete solar cells (including thick and thin layers) enhanced by the LDS layers for an improved solar spectrum harvesting. Experimental results and numerical simulations show that the layers of the higher refractive index binder with larger particles result in the highest optical transmittance in the visible light spectrum. Finally we proved that scattering of the phosphor particles in the LDS layers may increase the overall light harvesting in the solar cell. We used numerical simulations to determine optimal layer composition for application in realistic thin-film photovoltaic devices. Surprisingly LDS layers with lower measured optical transmittance are more efficient when applied onto the solar cells due to graded refractive index and efficient light scattering. Therefore, our phosphor-filled LDS layers could possibly complement other light-coupling techniques in photovoltaics.

  11. Polymorph control of luminescence properties in molecular crystals of a platinum and organoarsenic complex and formation of stable one-dimensional nanochannel.

    Science.gov (United States)

    Unesaki, Hikaru; Kato, Takuji; Watase, Seiji; Matsukawa, Kimihiro; Naka, Kensuke

    2014-08-18

    The mononuclear diiodoplatinum(II) complex (trans-PtI2(cis-DHDAMe)2), where cis-DHDAMe = cis-1,4-dihydro-1,4-dimethyl-2,3,5,6-tetrakis(methoxycarbonyl)-1,4-diarsinine, forms three different crystalline polymorphs that can be either concomitantly or separately obtained on varying the recrystallization conditions. Cubic red crystals (α-phase) and red-orange needles (β-phase) exhibit solid-state red emissions at room temperature. Cubic red crystals of the γ-phase show no solid-state emission at room temperature. All crystalline structures were confirmed by X-ray crystallography. Room-temperature strongly luminescent crystals (α-phase) (λem = 657 nm, Φ = 0.52) have a triclinic P1 (No. 2) structure and no voids in the crystal structure. Red-orange needle-shaped crystals of the β-phase exhibit moderate red luminescence (λem = 695 nm, Φ = 0.09) at room temperature and have a trigonal, R3 (No. 148), structure. In the needlelike crystals of the β-phase, stable hexagonal arrays of nanoporous channels, 5.0 Å in diameter, are formed. Room-temperature nonluminescent crystals (γ-phase) have an orthorhombic, Pbca (No. 61), structure with a void volume that is 4.9% of the total crystal volume. After heating the α-phase crystals at 150 °C for 2 min, a powder XRD pattern different from the original crystal is obtained, and its solid-state emission at room temperature decreased. After heating the β-phase crystals at 150 °C for 2 min, the emission wavelength and the quantum yield of the solid-state emission at room temperature and the powder XRD pattern are the same as those of the α-phase after heating at 150 °C. A crystal-to-crystal transition triggered by the thermal stimulus produces a different stable polymorph of the mononuclear diiodoplatinum(II) complex. The one-dimensional nanoporous crystals encapsulated iodine without distorting the crystal packing.

  12. Thermally Stable Heterocyclic Imines as New Potential Nonlinear Optical Materials

    Science.gov (United States)

    Nesterov, Volodymyr V.; Antipin, Mikhail Y.; Nesterov, Vladimir N.; Moore, Craig E.; Cardelino, Beatriz H.; Timofeeva, Tatiana V.

    2004-01-01

    In the course of a search for new thermostable acentric nonlinear optical crystalline materials, several heterocyclic imine derivatives were designed, with the general structure D-pi-A(D'). Introduction of a donor amino group (D') into the acceptor moiety was expected to bring H-bonds into their crystal structures, and so to elevate their melting points and assist in an acentric molecular packing. Six heterocycle-containing compounds of this type were prepared, single crystals were grown for five of them, and these crystals were characterized by X-ray analysis. A significant melting temperature elevation was found for all of the synthesized compounds. Three of the compounds were also found to crystallize in acentric space groups. One of the acentric compounds is built as a three-dimensional H-bonded molecular network. In the other two compounds, with very similar molecular structure, the molecules form one-dimensional H-bonded head-to-head associates (chains). These chains are parallel in two different crystallographic directions and form very unusual interpenetrating chain patterns in an acentric crystal. Two of the compounds crystallized with centrosymmetric molecular packing.

  13. Dose response of commercially available optically stimulated luminescent detector, Al2O3:C for megavoltage photons and electrons.

    Science.gov (United States)

    Kim, Dong Wook; Chung, Weon Kuu; Shin, Dong Oh; Yoon, Myonggeun; Hwang, Ui-Jung; Rah, Jeong-Eun; Jeong, Hojin; Lee, Sang Yeob; Shin, Dongho; Lee, Se Byeong; Park, Sung Yong

    2012-04-01

    This study examined the dose response of an optically stimulated luminescence dosemeter (OSLD) to megavoltage photon and electron beams. A nanoDot™ dosemeter was used to measure the dose response of the OSLD. Photons of 6-15 MV and electrons of 9-20 MeV were delivered by a Varian 21iX machine (Varian Medical System, Inc. Milpitas, CA, USA). The energy dependency was photons, the dose was linear until 200 cGy. The superficial dose measurements revealed photon irradiation to have an angular dependency. The nanoDot™ dosemeter has potential use as an in vivo dosimetric tool that is independent of the energy, has dose linearity and a rapid response compared with normal in vivo dosimetric tools, such as thermoluminescence detectors. However, the OSLD must be treated very carefully due to the high angular dependency of the photon beam.

  14. Structure, optical and photoluminescence properties of LiGd1-xErx(WO4)2 green luminescence phosphor

    Science.gov (United States)

    Demiaï, A.; Derbal, M.; Guerbous, L.; Rekik, B.

    2017-03-01

    Double tungstate of lithium and trivalent gadolinium ions were prepared by mean of solid state reaction, and have been studied using X-ray diffraction, Raman scattering and photoluminescence analysis. The Er3+ concentration effects on the structural and optical properties were studied. The compounds crystallize in the scheelite like structure with space group I41/a, and Z = 2. Spectroscopic and structural properties of the Er3+ ions doping elements in LiGd(WO4)2 have been determined at room temperature. Steady and time resolved photoluminescence spectroscopies of the synthesized compounds are reported. Samples exhibit intense green emission of Er3+ (4S3/2 → 4I15/2 and 2H11/2 → 4I15/2 transitions) under 377 nm excitation wavelength and present luminescent quenching around 3 at% Er3+ concentration. The decay time decrease with increasing the Er3+ concentration.

  15. Ag7+ ion induced modification of morphology, optical and luminescence behaviour of charge compensated CaMoO4 nanophosphor

    Science.gov (United States)

    Dutta, S.; Som, S.; Kunti, A. K.; Sharma, S. K.; Kumar, Vijay; Swart, H. C.; Visser, H. G.

    2016-10-01

    The present paper reports on the swift heavy ion (SHI) induced structural, optical and luminescence properties of CaMoO4:Dy3+/K+ nanophosphor synthesized via hydrothermal route. Herein 100 MeV Ag7+ ion beam was used varying fluence from 1 × 1011 to 1 × 1013 ions/cm2. The depth profile of the Ag7+ ions was estimated using SRIM code. XRD and FESEM results revealed the loss of crystallinity and reduction in particle size after SHI irradiations. The XPS technique confirmed the stability of oxidation states of the elements. Reflectance spectra exhibited a red shift in the absorption band, followed by a decrease in band gap. Decrease in the intensity of the photoluminescence peaks without any change in band positions was also obtained after ion irradiation. The thermoluminescence (TL) characteristics were discussed in detail, and the trapping parameter was calculated. The results were compared on the grounds of linear energy transfer of the irradiated ions.

  16. X-ray-excited optical luminescence of protein crystals: a new tool for studying radiation damage during diffraction data collection.

    Science.gov (United States)

    Owen, Robin L; Yorke, Briony A; Pearson, Arwen R

    2012-05-01

    During X-ray irradiation protein crystals radiate energy in the form of small amounts of visible light. This is known as X-ray-excited optical luminescence (XEOL). The XEOL of several proteins and their constituent amino acids has been characterized using the microspectrophotometers at the Swiss Light Source and Diamond Light Source. XEOL arises primarily from aromatic amino acids, but the effects of local environment and quenching within a crystal mean that the XEOL spectrum of a crystal is not the simple sum of the spectra of its constituent parts. Upon repeated exposure to X-rays XEOL spectra decay non-uniformly, suggesting that XEOL is sensitive to site-specific radiation damage. However, rates of XEOL decay were found not to correlate to decays in diffracting power, making XEOL of limited use as a metric for radiation damage to protein crystals. © 2012 International Union of Crystallography

  17. Measurement of Solid-State Optical Refrigeration by Two-Band Differential Luminescence Thermometry

    Science.gov (United States)

    2010-03-01

    induced cooling of a solid in 1995 produced a mere 0.3 K of cooling in the Yb3+-doped fluorozirconate glass (ZrF4–BaF2–LaF3–AlF3–NaF, ZBLAN ) [1...sensitivity is indicative of what can be achieved for a Yb3+-doped ZBLAN glass . Other materials will have dif- ferent luminescence spectra with...Model of laser cooling in the Yb3+-doped fluorozirconate glass ZBLAN ,” Phys. Rev. B 75, 144302 (2007). Fig. 8. TBDLT parameter [measured in vacuum

  18. Stable integrated hyper-parametric oscillator based on coupled optical microcavities

    CERN Document Server

    Armaroli, Andrea; Dumeige, Yannick

    2015-01-01

    We propose a flexible scheme based on three coupled optical microcavities which permits to achieve stable oscillations in the microwave range, the frequency of which depends only on the cavity coupling rates. We find the different dynamical regimes (soft and hard excitation) to affect the oscillation intensity but not their period. This configuration may permit to implement compact hyper-parametric sources on an integrated optical circuit, with interesting applications in communications, sensing and metrology.

  19. EVA thin film with thermo- and moisture-stable luminescent copolymer beads composed of Eu(III) complexes for improvement of energy conversion efficiency on silicon solar cell

    Science.gov (United States)

    Kataoka, Hisataka; Omagari, Shun; Nakanishi, Takayuki; Hasegawa, Yasuchika

    2015-04-01

    Luminescent beads composed of Eu(hfa)3(TPPO)2 (hfa: hexafluoroacetylacetonate, TPPO: triphenylphosphine oxide) in PMMA copolymer (polymethylmethacrylate- styrene and polymethylmethacrylate-trifluoromethylmethacrylate copolymers), PMMA-St-Eu and PMMA-TF-Eu have been reported for improvement of energy conversion efficiency on silicon solar cell. The PMMA-St-Eu and PMMA-TF-Eu beads are prepared using radical initiator AIBN (2,2-azobisisobutyronitrile) without BPO (Benzoyl peroxide) which promotes decomposition of Eu(hfa)3(TPPO)2. The emission properties of EVA (ethylene vinyl acetate) film with PMMA-St-Eu or PMMA-TF-Eu beads are characterized by the emission spectra and lifetimes. Thermo- and moisture-stabilities of the EVA films are performed under high temperature and high moisture condition (85°C85%RH). Increase percentage the solar cell short circuit current efficiency in the solar cell modulation using with EVA film containing PMMA-St-Eu beads with size in 70 μm was estimated to 1.2%. Thermo- and moisture-stable PMMA-St-Eu and PMMA-TF-Eu beads for solar sealing film are demonstrated for the first time.

  20. The use of the adding-doubling method for the optical optimization of planar luminescent down shifting layers for solar cells.

    Science.gov (United States)

    Leyre, Sven; Cappelle, Jan; Durinck, Guy; Abass, Aimi; Hofkens, Johan; Deconinck, Geert; Hanselaer, Peter

    2014-05-05

    To enhance the efficiency of solar cells, a luminescent down shifting layer can be applied in order to adapt the solar spectrum to the spectral internal quantum efficiency of the semiconductor. Optimization of such luminescent down shifting layers benefits from quick and direct evaluation methods. In this paper, the potential of the adding-doubling method is investigated to simulate the optical behavior of an encapsulated solar cell including a planar luminescent down shifting layer. The results of the adding-doubling method are compared with traditional Monte Carlo ray tracing simulations. The average relative deviation is found to be less than 1.5% for the absorptance in the active layer and the reflectance from the encapsulated cell, while the computation time can be decreased with a factor 52. Furthermore, the adding-doubling method is adopted to investigate the suitability of the SrB4O7:5%Sm2 + ,5%Eu2 + phosphor as a luminescent down shifting material in combination with a Copper Indium Gallium Selenide solar cell. A maximum increase of 9.0% in the short-circuit current can be expected if precautions are taken to reduce the scattering by matching the refractive index of host material to the phosphor particles. To be useful as luminescent down shifting material, the minimal value of the quantum yield of the phosphor is determined to be 0.64.

  1. FORMATION OF LUMINESCENT OPTICAL WAVEGUIDES IN SILICATE GLASS MATRIX BY THE ION-EXCHANGE TECHNIQUE

    Directory of Open Access Journals (Sweden)

    I. A. Dyomichev

    2015-01-01

    Full Text Available We present spectra of the alkali-silicate glasses with copper ions in near-surface area, introduced by ion exchange of different temperature and duration. It is shown that the reduction of Cu2+ in the near-surface area causes existence of Cu+ and neutral atoms in glass after the ion-exchange in divalent salt. The ion-exchange itself involves only Cu+ and Na+ ions. The formation of subnanometer clusters Cun is due to neutral copper atoms staying in near-surface zone. We have shown that the waveguide layer in near-surface area, made by ion-exchange, has а visible luminescence with the excitation by UVradiation. At the same time, the contribution to luminescence is made by Cu+ ions, molecular clusters Cun and by dimers Cu+ - Cu+ . During the high-temperature ion-exchange at 600 °С the formation and destruction equilibrium shift of molecular clusters Cun can be seen. An hour ion-exchange leads to molecular clusters Cun destruction, while at time periods less than 30 min and around 18 hours it leads to the formation of Cun. The sample turns green after 18,5 hours ion-exchange showing formation of a considerable amount of divalent copper ions Cu2+ therein.

  2. Magnesium-Aluminum-Zirconium Oxide Amorphous Ternary Composite: A Dense and Stable Optical Coating

    Science.gov (United States)

    Sahoo, N. K.; Shapiro, A. P.

    1998-01-01

    In the present work, the process parameter dependent optical and structural properties of MgO-Al(2)O(3)-ZrO(2) ternary mixed-composite material have been investigated. Optical properties were derived from spectrophotometric measurements. The surface morphology, grain size distributions, crystallographic phases and process dependent material composition of films have been investigated through the use of Atomic Force Microscopy (AFM), X-ray diffraction analysis and Energy Dispersive X- ray (EDX) analysis. EDX analysis made evident the correlation between the optical constants and the process dependent compositions in the films. It is possible to achieve environmentally stable amorphous films with high packing density under certain optimized process conditions.

  3. Influence of surface coating on structural, morphological and optical properties of upconversion-luminescent LaF3:Yb/Er nanoparticles

    Science.gov (United States)

    Ansari, Anees A.; Yadav, Ranvijay; Rai, S. B.

    2016-07-01

    LaF3:Yb/Er (core), LaF3:Yb/Er@LaF3 (core/shell) and LaF3:Yb/Er@LaF3@SiO2 (core/shell/SiO2) nanoparticles were synthesized using citric-acid-based complexation process. X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray analysis, optical absorption, band-gap energy ( E g), Fourier transform infrared and upconversion emission spectroscopy were employed to investigate the structural, morphological and optical properties of the synthesized core and core/shell/SiO2 nanoparticles. These core/shell/SiO2 nanoparticles can be well dispersed in aqueous solvents to form clear colloidal solution. The optical band-gap energy was decreased after shell formation due to increase in the crystalline size. The growth of an inactive and porous silica layers simultaneously on the surface of luminescent core-nanoparticles resulting an increase in average crystalline size of the nanoparticles. As-prepared inert shell-coated core/shell nanoparticles show intensive upconversion-luminescence as compared to the seed-core and silica-surface-modified core/shell/SiO2 nanoparticles because luminescent ions (Yb3+ and Er3+) ions located at the particle surface were protected from the non-radiative decay arising from surface dangling bonds and capping agent. However, our study revealed that there was only a slight reduction in upconversion efficiency for the silica-modified core/shell nanoparticles, indicating that upconversion properties of the upconversion nanoparticles are largely preserved in the core/shell/SiO2 nanoparticles. Absorption and upconversion-luminescence properties were examined for future application in the development of optical devices as well as optical bioprobes.

  4. Synthetic Aspects and Electro-Optical Properties of Fluorinated Arylenevinylenes for Luminescence and Photovoltaics

    Directory of Open Access Journals (Sweden)

    Antonio Cardone

    2013-03-01

    Full Text Available In this review, the main synthetic aspects and properties of fluorinated arylenevinylene compounds, both oligomers and polymers, are summarized and analyzed. Starting from vinyl organotin derivatives and aryl halides, the Stille cross-coupling reaction has been successfully applied as a versatile synthetic protocol to prepare a wide series of π-conjugated compounds, selectively fluorinated on the aromatic and/or vinylene units. The impact of fluoro-functionalization on properties, the solid state organization and intermolecular interactions of the synthesized compounds are discussed, also in comparison with the non-fluorinated counterparts. Luminescent and photovoltaic applications are also discussed, highlighting the role of fluorine on the performance of devices.

  5. A new flexible system for measuring thermally and optically stimulated luminescence

    DEFF Research Database (Denmark)

    Markey, B.G.; Bøtter-Jensen, L.; Duller, G.A.T.

    1997-01-01

    The automated Riso TL/OSL reader system is used worldwide for luminescence dating, retrospective dosimetry environmental dosimetry and material characterization. In response to requests from many users we have re-designed the reader by incorporating a variety of new hardware and software features....... New hardware features include a two-speed sample turntable, a new detachable beta irradiator with a Be window vacuum interface and the incorporation of an on-board minicomputer.,A completely new software concept was developed that allows the user unlimited control of the reader and has, at the same...... time, made the new generation Riso TL/OSL readers extremely flexible and user friendly. A description of the new system is given and measurement results are presented to demonstrate its capabilities. (C) 1997 Elsevier Science Ltd....

  6. Luminescence dating of Netherlands’ sediments

    OpenAIRE

    Wallinga, J.; Davids, F.; Dijkmans, J.W.A.

    2007-01-01

    Over the last decades luminescence dating techniques have been developed that allow earth scientists to determine the time of deposition of sediments. In this contribution we review: 1) the development of the methodology; 2) tests of the reliability of luminescence dating on Netherlands’ sediments; and 3) geological applications of the method in the Netherlands. Our review shows that optically stimulated luminescence dating of quartz grains using the single aliquot regenerative dose method yi...

  7. Electronic structure and optical properties of CdS{sub x}Se{sub 1−x} solid solution nanostructures from X-ray absorption near edge structure, X-ray excited optical luminescence, and density functional theory investigations

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, M. W. [DESY (Deutsches Elektronen-Synchrotron), FS-PEX, Notkestrasse 85, 22607 Hamburg (Germany); Yiu, Y. M., E-mail: yyiu@uwo.ca; Sham, T. K. [Department of Chemistry, University of Western Ontario, London, ON N6A5B7 (Canada); Ward, M. J. [Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States); Liu, L. [Institute of Functional Nano and Soft Materials (FUNSOM) and Soochow University-Western University Center for Synchrotron Radiation Research, Soochow University, Suzhou, Jiangsu, 215123 (China); Hu, Y. [Canadian Light Source, University of Saskatchewan, Saskatoon, SK S7N2V3 (Canada); Zapien, J. A. [Center Of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR (China); Liu, Yingkai [Institute of Physics and Electronic Information, Yunnan Normal University, Kunming, Yunnan, 650500 (China)

    2014-11-21

    The electronic structure and optical properties of a series of iso-electronic and iso-structural CdS{sub x}Se{sub 1−x} solid solution nanostructures have been investigated using X-ray absorption near edge structure, extended X-ray absorption fine structure, and X-ray excited optical luminescence at various absorption edges of Cd, S, and Se. It is found that the system exhibits compositions, with variable local structure in-between that of CdS and CdSe accompanied by tunable optical band gap between that of CdS and CdSe. Theoretical calculation using density functional theory has been carried out to elucidate the observations. It is also found that luminescence induced by X-ray excitation shows new optical channels not observed previously with laser excitation. The implications of these observations are discussed.

  8. The influence of radiation-induced defects on thermoluminescence and optically stimulated luminescence of α-Al{sub 2}O{sub 3}:C

    Energy Technology Data Exchange (ETDEWEB)

    Nyirenda, A.N., E-mail: anyirenda@gmail.com; Chithambo, M.L.

    2017-04-15

    It is known that when α-Al{sub 2}O{sub 3}:C is exposed to excessive amounts of ionising radiation, defects are induced within its matrix. We report the influence of radiation-induced defects on the thermoluminescence (TL) and optically stimulated luminescence (OSL) measured from α-Al{sub 2}O{sub 3}:C after irradiation to 1000 Gy. These radiation-induced defects are thermally unstable in the region 450–650 °C and result in TL peaks in this range when the TL is measured at 1 °C/s. Heating a sample to 700 °C obliterates the radiation-induced defects, that is, the TL peaks corresponding to the radiation induced defects are no longer observed in the subsequent TL measurements when moderate irradiation doses below 10 Gy are used. The charge traps associated with these radiation-induced defects are more stable than the dosimetric trap when the sample is exposed to either sunlight or 470-nm blue light from LEDs. TL glow curves measured following the defect-inducing irradiation produce a dosimetric peak that is broader and positioned at a higher temperature than observed in glow curves obtained before the heavy irradiation. In addition, sample sensitization/desensitization occurs due to the presence of these radiation-induced defects. Furthermore, both the activation energy and the kinetic order of the dosimetric peak evaluated when the radiation-induced defects are present in the sample are significantly lower in value than those obtained when these defects are absent. The radiation-induced defects also affect the shape and total light sum of the OSL signal as well as the position and width of the resultant residual phototransferred thermoluminescence main peak.

  9. The influence of radiation-induced defects on thermoluminescence and optically stimulated luminescence of α-Al2O3:C

    Science.gov (United States)

    Nyirenda, A. N.; Chithambo, M. L.

    2017-04-01

    It is known that when α-Al2O3:C is exposed to excessive amounts of ionising radiation, defects are induced within its matrix. We report the influence of radiation-induced defects on the thermoluminescence (TL) and optically stimulated luminescence (OSL) measured from α-Al2O3:C after irradiation to 1000 Gy. These radiation-induced defects are thermally unstable in the region 450-650 °C and result in TL peaks in this range when the TL is measured at 1 °C/s. Heating a sample to 700 °C obliterates the radiation-induced defects, that is, the TL peaks corresponding to the radiation induced defects are no longer observed in the subsequent TL measurements when moderate irradiation doses below 10 Gy are used. The charge traps associated with these radiation-induced defects are more stable than the dosimetric trap when the sample is exposed to either sunlight or 470-nm blue light from LEDs. TL glow curves measured following the defect-inducing irradiation produce a dosimetric peak that is broader and positioned at a higher temperature than observed in glow curves obtained before the heavy irradiation. In addition, sample sensitization/desensitization occurs due to the presence of these radiation-induced defects. Furthermore, both the activation energy and the kinetic order of the dosimetric peak evaluated when the radiation-induced defects are present in the sample are significantly lower in value than those obtained when these defects are absent. The radiation-induced defects also affect the shape and total light sum of the OSL signal as well as the position and width of the resultant residual phototransferred thermoluminescence main peak.

  10. Ultra-stable optical clock with two cold-atom ensembles

    CERN Document Server

    Schioppo, M; McGrew, W F; Hinkley, N; Fasano, R J; Beloy, K; Yoon, T H; Milani, G; Nicolodi, D; Sherman, J A; Phillips, N B; Oates, C W; Ludlow, A D

    2016-01-01

    Atomic clocks based on optical transitions are the most stable, and therefore precise, timekeepers available. These clocks operate by alternating intervals of atomic interrogation with dead time required for quantum state preparation and readout. This non-continuous interrogation of the atom system results in the Dick effect, an aliasing of frequency noise of the laser interrogating the atomic transition. Despite recent advances in optical clock stability achieved by improving laser coherence, the Dick effect has continually limited optical clock performance. Here we implement a robust solution to overcome this limitation: a zero-dead-time optical clock based on the interleaved interrogation of two cold-atom ensembles. This clock exhibits vanishingly small Dick noise, thereby achieving an unprecedented fractional frequency instability of $6 \\times 10^{-17} / \\sqrt{\\tau}$ for an averaging time $\\tau$ in seconds. We also consider alternate dual-atom-ensemble schemes to extend laser coherence and reduce the stan...

  11. Luminescence chronology of "Old Red Sand" in Jinjiang and its implications for optical dating of sediments in South China

    Institute of Scientific and Technical Information of China (English)

    ZHANG JiaFu; YUAN BaoYin; ZHOU LiPing

    2008-01-01

    A weathered deposit in South China is widespread on the coastal areas of Fujian and Guangdong provinces, China. This deposit consists of slightly cemented, medium- to fine-grained sands, and is characterized by its colors of red, brown red, light reddish brown or dark yellowish orange, and is usually called "Old Red Sand". The uncertainty in its formation age has been a major obstacle to the study of this type of deposit. In this paper, optically stimulated luminescence (OSL) techniques were used to date the "Old Red Sand" sediments from Jinjiang, Fujian Province, China. The effect of the geochemical behavior of uranium and thorium in sediment during chemical weathering on estimation of annual dose was investigated. The results show that the change in annual dose due to weathering poses a major problem for the optical,dating of such weathered sediments. The optical dating of these weathered deposits will produce erroneous ages if average annual dose during burial cannot be correctly estimated. For the profiles studied, the OSL dates obtained on samples from the upper part do not represent the burial age of the samples. It is highly likely that they are underestimated due mainly to the accumulated radioactive elements as a result of chemical weathering. It is concluded that changes in annual dose due to chemical weathering must be considered when dating similar sediments in South China. With a detailed analysis of the OSL dating results, the chronology of the marine terraces in this area was suggested. The lowest terrace was formed at -3.5 ka and the second terrace was dated to -74 ka. The age of the highest terrace may not be established accurately, but is inferred to be older than the apparent OSL date of ~77 ka and so is the Paleolithic artifacts from it.

  12. Photostimulated near-infrared persistent luminescence as a new optical read-out from Cr3+-doped LiGa5O8

    Science.gov (United States)

    Liu, Feng; Yan, Wuzhao; Chuang, Yen-Jun; Zhen, Zipeng; Xie, Jin; Pan, Zhengwei

    2013-01-01

    In conventional photostimulable storage phosphors, the optical information written by x-ray or ultraviolet irradiation is usually read out as a visible photostimulated luminescence (PSL) signal under the stimulation of a low-energy light with appropriate wavelength. Unlike the transient PSL, here we report a new optical read-out form, photostimulated persistent luminescence (PSPL) in the near-infrared (NIR), from a Cr3+-doped LiGa5O8 NIR persistent phosphor exhibiting a super-long NIR persistent luminescence of more than 1,000 h. An intense PSPL signal peaking at 716 nm can be repeatedly obtained in a period of more than 1,000 h when an ultraviolet-light (250–360 nm) pre-irradiated LiGa5O8:Cr3+ phosphor is repeatedly stimulated with a visible light or a NIR light. The LiGa5O8:Cr3+ phosphor has promising applications in optical information storage, night-vision surveillance, and in vivo bio-imaging. PMID:23532003

  13. Optically stimulated luminescence age controls on late Pleistocene and Holocene coastal lithosomes, North Carolina, USA

    Science.gov (United States)

    Mallinson, D.; Burdette, K.; Mahan, S.; Brook, G.

    2008-01-01

    Luminescence ages from a variety of coastal features on the North Carolina Coastal Plain provide age control for shoreline formation and relative sea-level position during the late Pleistocene. A series of paleoshoreline ridges, dating to Marine Isotope Stage (MIS) 5a and MIS 3 have been defined. The Kitty Hawk beach ridges, on the modern Outer Banks, yield ages of 3 to 2??ka. Oxygen-isotope data are used to place these deposits in the context of global climate and sea-level change. The occurrence of MIS 5a and MIS 3 shorelines suggests that glacio-isostatic adjustment (GIA) of the study area is large (ca. 22 to 26??m), as suggested and modeled by other workers, and/or MIS 3 sea level was briefly higher than suggested by some coral reef studies. Correcting the shoreline elevations for GIA brings their elevation in line with other sea-level indicators. The age of the Kitty Hawk beach ridges places the Holocene shoreline well west of its present location at ca. 3 to 2??ka. The age of shoreline progradation is consistent with the ages of other beach ridge complexes in the southeast USA, suggesting some regionally contemporaneous forcing mechanism. ?? 2007 University of Washington.

  14. Optical, scintillation and thermally stimulated luminescence properties of Ce-doped yttrium-aluminum-indium garnet

    Science.gov (United States)

    Mori, Masaki; Okada, Go; Kawaguchi, Noriaki; Yanagida, Takayuki

    2017-01-01

    We have investigated the photoluminescence (PL), scintillation and thermally stimulated luminescence (TSL) properties of 1 mol % Ce-doped Y3(Al X In1- X )5O12 (X = 0-1 Ce:YAING). These samples showed strong and broad PL emission by Ce3+ ion appeared in the spectral range from 480 to 620 nm. The PL decay profiles can be represented by a first-order exponential function with the decay time ranging 39-62 ns. Furthermore, the scintillation spectra showed similar features with those observed in PL. The scintillation decay time profiles were approximated by second or third order exponential decay functions, and we observed 26-61 ns component due to Ce3+ emission. The X-ray induced afterglow levels of Ce:YAING were worse than that of Ce:Y3Al5O12. The pulse height spectra of Ce:Y3(Al0.26In0.74)5O12 showed a clear photoabsorption peak, and that of the scintillation light yield was around 6,700 photons/MeV. In TSL glow curves, Ce:YAING show the glow peak at around 110 °C.

  15. Optical fibre luminescence sensor for real-time LDR brachytherapy dosimetry

    Science.gov (United States)

    Woulfe, P.; Sullivan, F. J.; O'Keeffe, S.

    2016-05-01

    An optical fibre sensor for monitoring low dose radiation is presented. The sensor is based on a scintillation material embedded within the optical fibre core, which emits visible light when exposed to low level ionising radiation. The incident level of ionising radiation can be determined by analysing the optical emission. An optical fibre sensor is presented, based on radioluminescence whereby radiation sensitive scintillation material, terbium doped gadolinium oxysulphide (Gd2O2S:Tb), is embedded in a cavity of 250μm of a 500μm plastic optical fibre. The sensor is designed for in-vivo monitoring of the radiation dose during radio-active seed implantation for brachytherapy, in prostate cancer treatment, providing oncologists with real-time information of the radiation dose to the target area and/or nearby critical structures. The radiation from the brachytherapy seeds causes emission of visible light from the scintillation material through the process of radioluminescence, which penetrates the fibre, propagating along the optical fibre for remote detection using a multi-pixel photon counter. The sensor demonstrates a high sensitivity to Iodine-125, the radioactive source most commonly used in brachytherapy for treating prostate cancer.

  16. Stable scalable control of soliton propagation in broadband nonlinear optical waveguides

    CERN Document Server

    Peleg, Avner; Huynh, Toan T

    2015-01-01

    We develop a method for achieving scalable transmission stabilization and switching of $N$ colliding soliton sequences in optical waveguides with broadband delayed Raman response and narrowband nonlinear gain-loss. We show that dynamics of soliton amplitudes in $N$-sequence transmission is described by a generalized $N$-dimensional predator-prey model. Stability and bifurcation analysis for the predator-prey model are used to obtain simple conditions on the physical parameters for robust transmission stabilization as well as on-off and off-on switching of $M$ out of $N$ soliton sequences. Numerical simulations with a system of $N$ coupled nonlinear Schr\\"odinger equations with $2 \\le N \\le 4$ show excellent agreement with the predator-prey model's predictions and stable propagation over significantly larger distances compared with other broadband nonlinear waveguides. Moreover, stable on-off and off-on switching of multiple soliton sequences and stable multiple transmission switching events are demonstrated b...

  17. Syntheses, structural characterization, luminescence and optical studies of Ni(II) and Zn(II) complexes containing salophen ligand

    Science.gov (United States)

    More, M. S.; Pawal, S. B.; Lolage, S. R.; Chavan, S. S.

    2017-01-01

    Some Ni(II) (1a-d) and Zn(II) (2a-d) salophen complexes were prepared by the treatment of 5-bromosalicylaldehyde, 5-(trimethylsilylethynyl)salicylaldehyde, 5-(4-nitrophenyl)ethynylsalicylaldehyde or 5-(4-methoxyphenyl)ethynylsalicylaldehyde with nickel acetate or zinc acetate followed by addition of 2,3-diamino-5-bromopyridine. All complexes were characterized by elemental analyses, IR, 1H NMR and mass spectral studies. X-ray powder diffraction of representative complexes 1c and 2b and SEM studies of 1b and 2d are used to elucidate the crystal structure and morphology of the complexes. The electrochemical behavior reveals that the redox responses of Ni(II) complexes shifted to more negative potential in order to increase the π-conjugation in the complexes. Room temperature luminescence is observed for all complexes corresponding to π→π* ILCT transition with some MLCT character in DMF and is finely tuned by the degree of extended π-conjugation and variation of the substituent group with different electronic effects in the complexes. The second harmonic generation (SHG) efficiency of the complexes was screened by Kurtz-powder technique indicating that all complexes possesses promising potential for the application as a useful nonlinear optical material.

  18. Optical thermometry based on luminescence behavior of Dy{sup 3+}-doped transparent LaF{sub 3} glass ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Y.Y. [Nanjing University of Posts and Telecommunications, College of Electronic Science and Engineering, Nanjing (China); Nanjing University of Posts and Telecommunications, College of Science, Nanjing (China); Cheng, S.J.; Wang, X.F. [Nanjing University of Posts and Telecommunications, College of Electronic Science and Engineering, Nanjing (China); Key Laboratory of Radio Frequency and Micro-Nano Electronics of Jiangsu Province, Nanjing, Jiangsu (China); Yan, X.H. [Nanjing University of Posts and Telecommunications, College of Electronic Science and Engineering, Nanjing (China); Key Laboratory of Radio Frequency and Micro-Nano Electronics of Jiangsu Province, Nanjing, Jiangsu (China); Nanjing University of Aeronautics and Astronautics, College of Science, Nanjing (China)

    2015-11-15

    Dy{sup 3+}-doped transparent LaF{sub 3} glass ceramics were fabricated, and its structures of resulting glass ceramics are studied by the X-ray diffraction and transmission electron microscopy. Optical temperature sensing of the resulting glass ceramics in the temperature range from 298 to 523 K is studied based on the down-conversion luminescence of Dy{sup 3+} ion. By using fluorescence intensity ratio method, the {sup 4}I{sub 15/2} and {sup 4}F{sub 9/2} of Dy{sup 3+} ions are verified as thermally coupled levels. A minimum S{sub R} = 1.16 x 10{sup -4} K{sup -1} is obtained at T = 294 K. By doping Eu{sup 3+} ion, the overall emission color of Eu{sup 3+}-Dy{sup 3+} co-doped transparent glass ceramics can be tuned from white to yellow with the temperature increase through energy transfer between Eu{sup 3+} and Dy{sup 3+}. Additionally, the thermal stability of the Dy{sup 3+} single-doped transparent glass ceramics becomes higher after doping Eu{sup 3+} ion. (orig.)

  19. Characterization of Al2O3 optically stimulated luminescence films for 2D dosimetry using a 6 MV photon beam

    Science.gov (United States)

    Ahmed, M. F.; Shrestha, N.; Schnell, E.; Ahmad, S.; Akselrod, M. S.; Yukihara, E. G.

    2016-11-01

    This work evaluates the dosimetric properties of newly developed optically stimulated luminescence (OSL) films, fabricated with either Al2O3:C or Al2O3:C,Mg, using a prototype laser scanning reader, a developed image reconstruction algorithm, and a 6 MV therapeutic photon beam. Packages containing OSL films (Al2O3:C and Al2O3:C,Mg) and a radiochromic film (Gafchromic EBT3) were irradiated using a 6 MV photon beam using different doses, field sizes, with and without wedge filter. Dependence on film orientation of the OSL system was also tested. Diode-array (MapCHECK) and ionization chamber measurements were performed for comparison. The OSLD film doses agreed with the MapCHECK and ionization chamber data within the experimental uncertainties (response was approximately linear from the MDD up to a few grays (the linearity correction was  response, resolution and dosimetric properties. The negligible background and potential simple calibration make these OSLD films suitable for remote audits. The characterization presented here may motivate further commercial development of a 2D dosimetry system based on the OSL from Al2O3:C or Al2O3:C,Mg.

  20. Detection of herbs and spices irradiated through optically stimulated luminescence; Deteccion de hierbas y especias irradiadas mediante luminiscencia opticamente estimulada

    Energy Technology Data Exchange (ETDEWEB)

    Preciado, S.; Agundez A, Z.; Barboza F, M. [Centro de Investigacion en Fisica, Universidad de Sonora, A.P. 5-088, 83190 Hermosillo, Sonora (Mexico); Cruz Z, E. [Instituto de Ciencias Nucleares de la UNAM, 04510 Mexico D.F. (Mexico)

    2003-07-01

    The irradiation of foods is one of the common practices in several countries of the American and European continents. In spite of the widespread use of irradiation methods and technics of nutritious products, it doesn't exist a method of general use at the present time for the detection of previously submitted foods to irradiation with pasteurization ends or sterilization. In the present work the results are presented obtained in the detection of herbs and spices exposed to radiation in the range of 0.1 - 3 KGy, by means of the photostimulation with light of 470 nm. It was used for it a RIS0 model team TL/OSL-GIVE-15 conditioned with a {beta} ray source, {sup 90}Sr/{sup 90}Y and a source of light of 50 mW/cm2. samples of chili guajillo were studied, pepper, cumin, mint and camomile; achieving you to detect exhibitions of the order of 8.33x10{sup -4} KGy that which is indicative of the high sensitivity of the luminescence technique optically stimulated. The answer of the samples with regard to the radiation dose presents a range of lineality for low dose of the order of 0.5 KGy; and supralineal for further dose without to arrive to a saturation stage. (Author)

  1. Optically stimulated luminescence of Tb{sup 3+}/Sm{sup 3+} doubly doped K{sub 2}YF{sub 5} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, L.; Marcazzo, J.; Santiago, M.; Caselli, E. [Universidad Nacional del Centro de la Provincia de Buenos Aires, Instituto de Fisica Arroyo Seco, Gral. Pinto 399, B7000GHG, Tandil (Argentina); Khaidukov, N. M., E-mail: jmarcass@exa.unicen.edu.ar [Kurnakov Institute of General and Inorganic Chemistry, RAS, Leninskii Prospekt 31, 119991 Moscow (Russian Federation)

    2014-08-15

    In this work optically stimulated luminescence (OSL) properties of K{sub 2}YF{sub 5} crystals doubly doped with Tb{sup 3+} and Sm{sup 3+} ions have been investigated for the first time. OSL responses for different dopant concentration and for optical stimulation with different wavelengths have been analyzed for each compound. Dosimetric properties of the most efficient composition, namely, K{sub 2}YF{sub 5}:1.0 at.% Tb{sup 3+}; 1.0 at.% Sm{sup 3+}, have been studied. Finally, the possible application of this single crystal as OSL dosimeter has been evaluated. (Author)

  2. Enhanced luminescence in Er-doped Si nanoparticles

    Science.gov (United States)

    Hoang, Tuan; Mantey, Kevin; Nayfeh, Munir

    2010-03-01

    We have studied the effect of Er ions on the luminescence of the 1-nm and 2.9-nm Si particles in solution. Under UV illumination, the 1-nm and 2.9-nm Si particles are known to have broadband luminescence in the blue and red region, respectively. We observed an enhancement in the luminescence of the particles with increasing concentration of Er ions. We discuss the result in terms of doping of the nanoparticles with Er ions. Preliminary DFT calculation shows that the ion can form a stable state just inside the particle. In this state, the electric field of the Er ion changes the bond length of the dimers, which are believed to be responsible for the optical activity of the particles.

  3. Method of measuring luminescence of a material

    Science.gov (United States)

    Miller, Steven D.

    2015-12-15

    A method of measuring luminescence of a material is disclosed. The method includes applying a light source to excite an exposed material. The method also includes amplifying an emission signal of the material. The method further includes measuring a luminescent emission at a fixed time window of about 10 picoseconds to about 10 nanoseconds. The luminescence may be radio photoluminescence (RPL) or optically stimulated luminescence (OSL).

  4. Time-resolved luminescence from quartz

    NARCIS (Netherlands)

    Chithambo, M.L.; Ankjærgaard, C.; Pagonis, V.

    2016-01-01

    Time-resolved optical stimulation of luminescence has become established as a key method for measurement of optically stimulated luminescence from quartz, feldspar and α-Al2O3:C, all materials of interest in dosimetry. The aim of time-resolved optical stimulation is to separ

  5. Optical lattice-like cladding waveguides by direct laser writing: fabrication, luminescence, and lasing.

    Science.gov (United States)

    Nie, Weijie; He, Ruiyun; Cheng, Chen; Rocha, Uéslen; Rodríguez Vázquez de Aldana, Javier; Jaque, Daniel; Chen, Feng

    2016-05-15

    We report on the fabrication of optical lattice-like waveguide structures in an Nd:YAP laser crystal by using direct femtosecond laser writing. With periodically arrayed laser-induced tracks, the waveguiding cores can be located in either the regions between the neighbored tracks or the central zone surrounded by a number of tracks as outer cladding. The polarization of the femtosecond laser pulses for the inscription has been found to play a critical role in the anisotropic guiding behaviors of the structures. The confocal photoluminescence investigations reveal different stress-induced modifications of the structures inscribed by different polarization of the femtosecond laser beam, which are considered to be responsible for the refractive index changes of the structures. Under optical pump at 808 nm, efficient waveguide lasing at ∼1  μm wavelength has been realized from the optical lattice-like structure, which exhibits potential applications as novel miniature light sources.

  6. Delivering pulsed and phase stable light to atoms of an optical clock

    CERN Document Server

    Falke, Stephan; Sterr, Uwe; Lisdat, Christian

    2011-01-01

    In optical clocks, transitions of ions or neutral atoms are interrogated using pulsed ultra-narrow laser fields. Systematic phase chirps of the laser or changes of the optical path length during the measurement cause a shift of the frequency seen by the interrogated atoms. While the stabilization of cw-optical links is now a well established technique even on long distances, phase stable links for pulsed light pose additional challanges and have not been demonstrated so far. In addition to possible temperature or pressure drift of the laboratory, which may lead to a Doppler shift by steadily changing the optical path length, the pulsing of the clock laser light calls for short settling times of stabilization locks. Our optical path length stabilization uses retro-reflected light from a mirror that is fixed with respect to the interrogated atoms and synthetic signals during the dark time. Length changes and frequency chirps are compensated for by the switching AOM. For our strontium optical lattice clock we ha...

  7. Time structure measurement of the storage ring with the time-resolved X-ray excited optical luminescence method at SSRF

    CERN Document Server

    Zhaohong, Zhang; Song, Xue; Lifang, Zheng

    2014-01-01

    Measuring the time structure of the storage ring on the sample spot inside the experimental hutch is a foundational step during the time-resolved experiments using the pulsed synchrotron X-rays with the time structure defined by the storage ring. In this work, the method of time-resolved X-ray excited optical luminescence was designed and implemented to do the measurement. This method is based on the principle of time-correlated single photon counting techniques. The measurement system consists of a spectrometer with a detector of photomultiplier tube, a timing system, a set of Nuclear Instrument Modules and a luminescent material of Zinc Oxide. The measurement was performed on the X-ray absorbed fine structure spectrum beamline at Shanghai Synchrotron Radiation Facility. The results show that this system can be used to measure the time structure of the storage ring with a precision of less than 1 ns.

  8. Complexation of lactate with neodymium(III) and europium(III) at variable temperatures: studies by potentiometry, microcalorimetry, optical absorption, and luminescence spectroscopy.

    Science.gov (United States)

    Tian, Guoxin; Martin, Leigh R; Rao, Linfeng

    2010-11-15

    The complexation of neodymium(III) and europium(III) with lactate was studied at variable temperatures by potentiometry, absorption spectrophotometry, luminescence spectroscopy, and microcalorimetry. The stability constants of three successive lactate complexes (ML(2+), ML(2)(+), and ML(3)(aq), where M stands for Nd and Eu and L stands for lactate) at 10, 25, 40, 55, and 70 °C were determined. The enthalpies of complexation at 25 °C were determined by microcalorimetry. Thermodynamic data show that the complexation of trivalent lanthanides (Nd(3+) and Eu(3+)) with lactate is exothermic and the complexation becomes weaker at higher temperatures. Results from optical absorption and luminescence spectroscopy suggest that the complexes are inner-sphere chelate complexes in which the protonated α-hydroxyl group of lactate participates in the complexation.

  9. Luminescence excitation characteristics of Ca-, Na- and K-aluminosilicates (feldspars), in the stimulation range 20-500 eV: optical detection of XAS

    CERN Document Server

    Poolton, N R J; Quinn, F M; Pantos, E; Andersen, C E; Bøtter-Jensen, L; Johnsen, O; Murray, A S

    2003-01-01

    We demonstrate that the visible/UV luminescence from common feldspar crystals (NaAlSi sub 3 O sub 8 , KAlSi sub 3 O sub 8 and CaAl sub 2 Si sub 2 O sub 8) can be used to detect detailed L-edge and associated near-edge absorption structure of the main constituent atoms (Ca, K, Na, Al, Si), when exciting in the energy range 20-500 eV. Comparisons of the spectral features are drawn with similar measurements made on the associated materials SiO sub 2 , Al sub 2 O sub 3 and CaCO sub 3. The potential for using optically detected x-ray absorption spectroscopy as a method for identifying the luminescent components of mixed mineral samples is considered.

  10. Luminescence excitation characteristics of Ca-, Na- and K-aluminosilicates (feldspars), in the stimulation range 20-500 eV: optical detection of XAS

    Energy Technology Data Exchange (ETDEWEB)

    Poolton, N R J [Synchrotron Radiation Department, Daresbury Laboratory, Warrington WA4 4AD, Cheshire (United Kingdom); Malins, A E R [Synchrotron Radiation Department, Daresbury Laboratory, Warrington WA4 4AD, Cheshire (United Kingdom); Quinn, F M [Synchrotron Radiation Department, Daresbury Laboratory, Warrington WA4 4AD, Cheshire (United Kingdom); Pantos, E [Synchrotron Radiation Department, Daresbury Laboratory, Warrington WA4 4AD, Cheshire (United Kingdom); Andersen, C E [Radiation Research Department, Riso National Laboratory, 4000 Roskilde (Denmark); Botter-Jensen, L [Radiation Research Department, Riso National Laboratory, 4000 Roskilde (Denmark); Johnsen, O [Geological Museum, University of Copenhagen, Oster Voldgade 5-7, 1350 Copenhagen (Denmark); Murray, A S [Nordic Laboratory for Luminescence Dating, Aarhus University, Riso National Laboratory, 4000 Roskilde (Denmark)

    2003-05-07

    We demonstrate that the visible/UV luminescence from common feldspar crystals (NaAlSi{sub 3}O{sub 8}, KAlSi{sub 3}O{sub 8} and CaAl{sub 2}Si{sub 2}O{sub 8}) can be used to detect detailed L-edge and associated near-edge absorption structure of the main constituent atoms (Ca, K, Na, Al, Si), when exciting in the energy range 20-500 eV. Comparisons of the spectral features are drawn with similar measurements made on the associated materials SiO{sub 2}, Al{sub 2}O{sub 3} and CaCO{sub 3}. The potential for using optically detected x-ray absorption spectroscopy as a method for identifying the luminescent components of mixed mineral samples is considered.

  11. Luminescence nanothermometry

    Science.gov (United States)

    Jaque, Daniel; Vetrone, Fiorenzo

    2012-07-01

    The current status of luminescence nanothermometry is reviewed in detail. Based on the main parameters of luminescence including intensity, bandwidth, bandshape, polarization, spectral shift and lifetime, we initially describe and compare the different classes of luminescence nanothermometry. Subsequently, the various luminescent materials used in each case are discussed and the mechanisms at the root of the luminescence thermal sensitivity are described. The most important results obtained in each case are summarized and the advantages and disadvantages of these approaches are discussed.The current status of luminescence nanothermometry is reviewed in detail. Based on the main parameters of luminescence including intensity, bandwidth, bandshape, polarization, spectral shift and lifetime, we initially describe and compare the different classes of luminescence nanothermometry. Subsequently, the various luminescent materials used in each case are discussed and the mechanisms at the root of the luminescence thermal sensitivity are described. The most important results obtained in each case are summarized and the advantages and disadvantages of these approaches are discussed. This work was supported by the Universidad Autónoma de Madrid and Comunidad Autónoma de Madrid (Project S2009/MAT-1756), by the Spanish Ministerio de Educacion y Ciencia (MAT2010-16161) and by Caja Madrid Foundation.

  12. Luminescence, optical and laser Raman scattering studies on γ -irradiated terbium-doped potassium iodide crystals

    Science.gov (United States)

    Bangaru, S.

    2011-02-01

    This paper reports the thermoluminescence (TL), optical absorption and other laser Raman scattering studies performed on terbium-doped KI crystals γ-irradiated at room temperature. Photoluminescence studies confirm the presence of terbium ions in the KI matrix in their trivalent form. Formation of V3- and Z1-centres on F-bleaching of γ-irradiated crystals was observed. The characteristic emission due to Tb3+ ions in the spectral distribution under optically stimulated emission and TL emission confirms the participation of the Tb3+ ions in the recombination process. The Raman bands were identified as the totally symmetric vibration modes of f.c.c. species KI:Tb3+.

  13. Coherent control of the optical absorption in a plasmonic lattice coupled to a luminescent layer

    CERN Document Server

    Pirruccio, Giuseppe; Rodriguez, Said Rahimzadeh-Kalaleh; Rivas, Jaime Gomez

    2016-01-01

    We experimentally demonstrate the coherent control, i.e., phase-dependent enhancement and suppression, of the optical absorption in an array of metallic nanoantennas covered by a thin lu- minescent layer. The coherent control is achieved by using two collinear, counter-propagating and phase-controlled incident waves with wavelength matching the absorption spectrum of dye molecules coupled to the array. Symmetry arguments shed light on the relation between the relative phase of the incident waves and the excitation efficiency of the optical resonances of the system. This coherent control is associated with a phase-dependent distribution of the electromagnetic near-fields in the structure which enables a significant reduction of the unwanted dissipation in the metallic structures.

  14. Identification of defects responsible for optically stimulated luminescence (OSL) from copper-diffused LiAlO{sub 2} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Holston, M.S.; Ferguson, I.P.; Giles, N.C.; McClory, J.W. [Department of Engineering Physics, Air Force Institute of Technology, Wright-Patterson Air Force Base, OH 45433 (United States); Halliburton, L.E., E-mail: Larry.Halliburton@mail.wvu.edu [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506 (United States)

    2015-08-15

    A large optically stimulated luminescence (CW-OSL) response has been observed from bulk lithium aluminate (LiAlO{sub 2}) crystals that have been copper-diffused. After introducing the copper, an optical absorption band peaking at 277 nm is present and is assigned to Cu{sup +} (3d{sup 10}) ions at Li{sup +} sites. Photoluminescence (PL and PLE) from copper-diffused samples shows an emission band near 359 nm and an excitation band near 273 nm. These PL bands are also assigned to the Cu{sup +} ions. After an irradiation at room temperature with x-rays, the copper-diffused crystals give an intense OSL signal when stimulated with light in the 425–500 nm region. The OSL emitted light has a peak near 357 nm and thus is directly associated with recombination at a Cu ion. Electron paramagnetic resonance (EPR) shows that the x-rays produce two distinct Cu{sup 2+} (3d{sup 9}) centers, both at Li{sup +} sites. One of the trapped-hole centers is a Cu{sup 2+} with no nearby defects and the other is a Cu{sup 2+} with a neighboring Li{sup +} vacancy. Monitoring the EPR spectra before and after OSL shows that only the isolated Cu{sup 2+} ions (i.e., those with no nearby defect) participate in the OSL process. The electron traps participating in the OSL are shown with EPR to be transition-metal ions that are unintentionally present. Specifically, Fe{sup 2+} ions replacing Li{sup +} ions, possibly with a nearby lithium vacancy, convert to Fe{sup +} (3d{sup 7}) ions when they trap an electron during irradiation. These electrons are optically released by the OSL exciting light and migrate to the holes trapped as isolated Cu{sup 2+} ions, where electron–hole recombination gives the characteristic Cu{sup +} emission. By combining OSL, PL, and EPR, we establish the general OSL mechanism in copper-diffused LiAlO{sub 2} crystals. - Highlights: • Copper is diffused into LiAlO{sub 2} crystals at high temperature. • Cu{sup +} ions at Li{sup +} sites cause PL at 359 nm and PLE at 273 nm

  15. Luminescence chronology of a second millenium BCE settlement near Porbandar on the Gujarat coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Gaur, A.S.; Thomas, P.J.; Vora, K.H.; Sundaresh

    ) and optically stimulated luminescence (OSL) dating of two potshards. The obtained luminescence ages are found to be in agreement with other archaeological findings. The implications of the luminescence ages on the maritime history of the area and the cultural...

  16. Fluorinated Poly(p-phenylenevinylenes: Synthesis and Optical Properties of an Intriguing Class of Luminescent Polymers

    Directory of Open Access Journals (Sweden)

    Gianluca M. Farinola

    2010-05-01

    Full Text Available This review is an overview of our previous work on the synthesis and properties of poly(p-phenylenevinylenes (PPVs selectively fluorinated in different positions of the conjugated backbone. Both the synthetic challenges and the effects of functionalization with fluorine atoms on the optical behavior are discussed, highlighting the peculiarities and the interest of this class of conjugated polymers. A general polymerization protocol for PPVs, that is based on the Pd-catalyzed Stille cross-coupling reaction of bis-stannylated vinylene monomers with aromatic bis-halides, has been successfully extended to the synthesis of selectively fluorinated poly(p-phenylenevinylenes. The properties of a series of these PPVs differing in the number and positions of the fluorine atoms on the conjugated backbone have been studied, even in comparison with the non-fluorinated counterparts. The intriguing optical features of the resulting materials are discussed considering not only the role of the electronic and steric effects induced by the fluorine substituents, but also the impact of the fluorination on the solid state organization and intermolecular interactions.

  17. Characteristics of thermally transferred optically stimulated luminescence (TT-OSL) in quartz and its potential for dating sediments

    Energy Technology Data Exchange (ETDEWEB)

    Tsukamoto, Sumiko [Institute of Geography and Earth Sciences, Aberystwyth University, Aberystwyth SY23 3DB (United Kingdom); Duller, Geoff A.T. [Institute of Geography and Earth Sciences, Aberystwyth University, Aberystwyth SY23 3DB (United Kingdom)], E-mail: ggd@aber.ac.uk; Wintle, Ann G. [Institute of Geography and Earth Sciences, Aberystwyth University, Aberystwyth SY23 3DB (United Kingdom)

    2008-08-15

    The temperature dependence, dose response and bleaching characteristics of the thermally transferred optically stimulated luminescence (TT-OSL) of sedimentary quartz were studied, in order to assess the potential of the TT-OSL signal for dating. The TT-OSL was separated into two components; recuperated OSL (ReOSL) and basic transfer (BT-OSL) by annealing samples at 300 deg. C for 10 s as suggested in an earlier study. Four quartz extracts were studied, two from loess from China and two from coastal sands from South Africa. The equivalent doses of the two recent samples (one sand and one loess) were {approx}15Gy and this suggests that the signal can be bleached by sunlight but may not be totally zeroed. The sensitivity-corrected ReOSL from the older samples did not reach zero and gave doses of 14 and 52 Gy, respectively, after 7 days bleaching with a solar simulator. A single aliquot regenerative dose (SAR) protocol using ReOSL was proposed and tested. In this protocol, a blue light stimulation at 280 deg. C for 100 s at the end of each cycle resulted in the recovery of identical sensitivity-corrected ReOSL values, in spite of {approx}20 -30% loss in sensitivity for the four samples that were tested. Two dose response curves were constructed using the sensitivity-corrected ReOSL, one for the initial 2 s signal and the other for the fast component obtained by curve fitting. Using the additional high temperature bleach and the separated fast component of the ReOSL, it was possible to recover given doses within 10%, up to {approx}1000Gy for the loess and {approx}2000Gy for the coarse grained quartz. However, the natural dose obtained for the older sand was twice that obtained using the conventional SAR OSL method.

  18. Determination of average LET of therapeutic proton beams using Al2O3:C optically stimulated luminescence (OSL) detectors.

    Science.gov (United States)

    Sawakuchi, Gabriel O; Sahoo, Narayan; Gasparian, Patricia B R; Rodriguez, Matthew G; Archambault, Louis; Titt, Uwe; Yukihara, Eduardo G

    2010-09-07

    In this work we present a methodology and proof of concept to experimentally determine average linear energy transfer (LET) of therapeutic proton beams using the optically stimulated luminescence (OSL) of small Al(2)O(3):C detectors. Our methodology is based on the fact that the shape of the OSL decay curve of Al(2)O(3):C detectors depends on the LET of the radiation field. Thus, one can use the shape of the OSL decay curves to establish an LET calibration curve, which in turn permits measurements of LET. We performed irradiations at the M D Anderson Cancer Center Proton Therapy Center, Houston (PTCH), with passive scattering beams. We determined the average LET of the passive scattering beams using a validated Monte Carlo model of the PTCH passive scattering nozzle and correlated them with the shape of the OSL decay curve to obtain an LET calibration curve. Using this calibration curve and OSL measurements, we determined the averaged LET at various water-equivalent depths for therapeutic spread-out Bragg peaks and compared the results with averaged LETs determined using the Monte Carlo simulations. Agreement between measured and simulated fluence-averaged LET was within 24% for low energy spread-out Bragg peak (SOBP) fields and within 14% for high energy SOBP fields. Agreement between measured and simulated dose-averaged LET was within 12% for low energy SOBP fields and within 47% for high energy SOBP fields. The data presented in this work demonstrated the correlation between the OSL decay curve shapes and the average LET of the radiation fields, providing proof of concept of the feasibility of using OSL from Al(2)O(3):C detectors to measure average LET of therapeutic proton beams.

  19. SU-E-T-600: In Vivo Dosimetry for Total Body and Total Marrow Irradiations with Optically Stimulated Luminescence Dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Niedbala, M; Save, C [The Ottawa Hospital Cancer Ctr., Ottawa, ON (Canada); Cygler, J [The Ottawa Hospital Cancer Ctr., Ottawa, ON (Canada); University of Ottawa (Canada); Carleton University (Canada)

    2014-06-01

    Purpose: To evaluate the feasibility of using optically stimulated luminescence dosimeters (OSLDs) for in-vivo dosimetry of patients undergoing Total Body and Total Marrow Irradiations (TBI and TMI). Methods: TBI treatments of 12 Gy were delivered in 6 BID fractions with the patient on a moving couch under a static 10 MV beam (Synergy, Elekta). TMI treatments of 18 Gy in 9 BID fractions were planned and delivered using a 6 MV TomoTherapy unit (Accuray). To provide a uniform dose to the entire patient length, the treatment was split into 2 adjacent fields junctioned in the thigh region. Our standard clinical practice involves in vivo dosimetry with MOSFETs for each TBI fraction and TLDs for at least one fraction of the TMI treatment for dose verification. In this study we also used OSLDs. Individual calibration coefficients were obtained for the OSLDs based on irradiations in a solid water phantom to the dose of 50 cGy from Elekta Synergy 10 MV (TBI) and 6 MV (TMI) beams. Calibration coefficients were calculated based on the OSLDs readings taken 2 hrs post-irradiation. For in vivo dosimetry OSLDs were placed alongside MOSFETs for TBI patients and in approximately the same locations as the TLDs for TMI patients. OSLDs were read 2 hours post treatment and compared to the MOSFET and TLD results. Results: OSLD measured doses agreed within 5% with MOSFET and TLD results, with the exception of the junction region in the TMI patient due to very high dose gradient and difficulty of precise and reproducible detector placement. Conclusion: OSLDs are useful for in vivo dosimetry of TBI and TMI patients. The quick post-treatment readout is an advantage over TLDs, allowing the results to be obtained between BID fractions, while wireless detectors are advantageous over MOSFETs for treatments involving a moving couch.

  20. Evaluation of an X-Ray Dose Profile Derived from an Optically Stimulated Luminescent Dosimeter during Computed Tomographic Fluoroscopy.

    Directory of Open Access Journals (Sweden)

    Hiroaki Hasegawa

    Full Text Available The purpose of this study was to evaluate scatter radiation dose to the subject surface during X-ray computed tomography (CT fluoroscopy using the integrated dose ratio (IDR of an X-ray dose profile derived from an optically stimulated luminescent (OSL dosimeter. We aimed to obtain quantitative evidence supporting the radiation protection methods used during previous CT fluoroscopy. A multislice CT scanner was used to perform this study. OSL dosimeters were placed on the top and the lateral side of the chest phantom so that the longitudinal direction of dosimeters was parallel to the orthogonal axis-to-slice plane for measurement of dose profiles in CT fluoroscopy. Measurement of fluoroscopic conditions was performed at 120 kVp and 80 kVp. Scatter radiation dose was evaluated by calculating the integrated dose determined by OSL dosimetry. The overall percent difference of the integrated doses between OSL dosimeters and ionization chamber was 5.92%. The ratio of the integrated dose of a 100-mm length area to its tails (-50 to -6 mm, 50 to 6 mm was the lowest on the lateral side at 80 kVp and the highest on the top at 120 kVp. The IDRs for different measurement positions were larger at 120 kVp than at 80 kVp. Similarly, the IDRs for the tube voltage between the primary X-ray beam and scatter radiation was larger on the lateral side than on the top of the phantom. IDR evaluation suggested that the scatter radiation dose has a high dependence on the position and a low dependence on tube voltage relative to the primary X-ray beam for constant dose rate fluoroscopic conditions. These results provided quantitative evidence supporting the radiation protection methods used during CT fluoroscopy in previous studies.

  1. Optical and radiation-induced luminescence properties of Ce-doped magnesium aluminoborate glasses

    Science.gov (United States)

    Nakauchi, Daisuke; Okada, Go; Fujimoto, Yutaka; Kawano, Naoki; Kawaguchi, Noriaki; Yanagida, Takayuki

    2017-10-01

    Optical, radioluminescence (RL) and thermoluminescence (TL) properties of magnesium aluminoborate glasses were evaluated. The samples were synthesized by the conventional melt-quenching technique using an alumina crucible under ambient atmosphere. After polishing, all the samples show good transparency. In photoluminescence, RL and TL, the emission is predominantly due to the 5d-4f transitions of Ce3+ appearing as a broad feature peaking around 300-500 nm, and the decay time constants are affected by concentration quenching but on the typical range for the 5d-4f transitions of Ce3+. TL glow curves are characterized as a single but broad glow peak over 100-300 °C, and the TL intensity monotonically increases with the X-ray dose irradiated over 1-10000 mGy.

  2. Luminescent, magnetic and optical properties of ZnO-ZnS nanocomposites

    Science.gov (United States)

    Raleaooa, Pule V.; Roodt, Andreas; Mhlongo, Gugu G.; Motaung, David E.; Kroon, Robin E.; Ntwaeaborwa, Odireleng M.

    2017-02-01

    The structure, particle morphology, optical and magnetic properties of ZnO, ZnS and ZnO-ZnS nanoparticles prepared by the sol-gel method are reported. ZnO and ZnS were combined at room temperature by an ex situ synthetic route to prepare ZnO-ZnS nanocomposites. The nanocomposites exhibited particle morphology different from that of ZnO and ZnS nanoparticles. The ZnO and ZnS nanoparticles exhibited quantum confinement as inferred from the widening of their respective bandgap energies. The electron paramagnetic resonance data provided evidence for the existence of magnetic clusters near the surface, electron to nuclei interactions and defect states. The ZnO-ZnS nanocomposites exhibited tunable emission that was dependent on the ratio of ZnO to ZnS. These composites were evaluated for application in different types of light emitting devices.

  3. Luminescent, magnetic and optical properties of ZnO-ZnS nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Raleaooa, Pule V. [Department of Physics, University of the Free State, ZA 9300 Bloemfontein (South Africa); Department of Chemistry, University of the Free State, ZA 9300 (South Africa); Roodt, Andreas [Department of Chemistry, University of the Free State, ZA 9300 (South Africa); Mhlongo, Gugu G.; Motaung, David E. [DST/CSIR Nanotechnology Innovation Center, National Center for Nano-Structured Materials, Council for Scientific and Industrial Research, P.O. Box 395, ZA 0001 Pretoria (South Africa); Kroon, Robin E. [Department of Physics, University of the Free State, ZA 9300 Bloemfontein (South Africa); Ntwaeaborwa, Odireleng M., E-mail: ntwaeab@gmail.com [School of Physics, University of the Witwatersrand, Private Bag 3, Wits, ZA 2050 (South Africa)

    2017-02-15

    The structure, particle morphology, optical and magnetic properties of ZnO, ZnS and ZnO-ZnS nanoparticles prepared by the sol-gel method are reported. ZnO and ZnS were combined at room temperature by an ex situ synthetic route to prepare ZnO-ZnS nanocomposites. The nanocomposites exhibited particle morphology different from that of ZnO and ZnS nanoparticles. The ZnO and ZnS nanoparticles exhibited quantum confinement as inferred from the widening of their respective bandgap energies. The electron paramagnetic resonance data provided evidence for the existence of magnetic clusters near the surface, electron to nuclei interactions and defect states. The ZnO-ZnS nanocomposites exhibited tunable emission that was dependent on the ratio of ZnO to ZnS. These composites were evaluated for application in different types of light emitting devices.

  4. Study of optical and luminescence properties of silicon — semiconducting silicide — silicon multilayer nanostructures

    Science.gov (United States)

    Galkin, N. G.; Galkin, K. N.; Dotsenko, , S. A.; Goroshko, D. L.; Shevlyagin, A. V.; Chusovitin, E. A.; Chernev, I. M.

    2016-12-01

    By method of in situ differential spectroscopy it was established that at the formation of monolayer Fe, Cr, Ca, Mg silicide and Mg stannide islands on the atomically clean silicon surface an appearance of loss peaks characteristic for these materials in the energy range of 1.1-2.6 eV is observed. An optimization of growth processes permit to grow monolithic double nanoheterostructures (DNHS) with embedded Fe, Cr and Ca nanocrystals, and also polycrystalline DNHS with NC of Mg silicide and Mg stannide and Ca disilicide. By methods of optical spectroscopy and Raman spectroscopy it was shown that embedded NC form intensive peaks in the reflectance spectra at energies up to 2.5 eV and Raman peaks. In DNS with β-FeSi2 NC a photoluminescence and electroluminescence at room temperature were firstly observed.

  5. The nature of unusual luminescence in natural calcite, CaCO3

    Energy Technology Data Exchange (ETDEWEB)

    Gaft, M.; Nagli, L.; Panczer, G.; Waychunas, G.; Porat, N.

    2008-11-01

    The unusual luminescence of particular varieties of natural pink calcite (CaCO{sub 3}) samples was studied by laser-induced time-resolved luminescence spectroscopy at different temperatures. The luminescence is characterized by intense blue emission under short-wave UV lamp excitation with an extremely long decay time, accompanied by pink-orange luminescence under long wave UV excitation. Our investigation included optical absorption, natural thermostimulated luminescence (NTL) and Laser-Induced Breakdown Spectroscopy (LIBS) studies. Two luminescence centers were detected: a narrow violet band, with {lambda}{sub max} = 412 nm, {Delta} = 45 nm, two decay components of {tau}{sub 1} = 5 ns and {tau}{sub 2} = 7.2 ms, accompanied by very long afterglow, and an orange emission band with {lambda}{sub max} = 595 nm, {Delta} = 90 nm and {tau} = 5 ns. Both luminescence centers are thermally unstable with the blue emission disappearing after heating at 500 C, and the orange emission disappearing after heating at different temperatures starting from 230 C, although sometimes it is stable up to 500 C in different samples. Both centers have spectral-kinetic properties very unusual for mineral luminescence, which in combination with extremely low impurity concentrations, prevent their identification with specific impurity related emission. The most likely explanation of these observations may be the presence of radiation-induced luminescence centers. The long violet afterglow is evidently connected with trapped charge carrier liberation, with their subsequent migration through the valence band and ultimate recombination with a radiation-induced center responsible for the unusual violet luminescence.

  6. Optically stimulated phosphorescence in quartz over the millisecond to second time scale: insights into the role of shallow traps in delaying luminescent recombination

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Jain, Mayank

    2010-01-01

    Time-resolved optically stimulated luminescence (TR-OSL) curves from quartz are usually measured over a few hundred microseconds because this time range best illustrates the main component in quartz which lies in the range 30–45 µs. In this study we present the decay form of quartz TR......-OSL and optically stimulated phosphorescence (OSP) covering over 8 orders of magnitude from 50 ns to ~8 s. A detailed characterization of the previously unstudied slowly decaying signals (millisecond–second time scales) is undertaken to understand the origin of these components and the role of re-trapping following...... optical stimulation. We present preheat and stimulation temperature dependence for both the TR-OSL and OSP curves in these time ranges and use the latter data to determine the E and s values for the participating shallow traps. We observe an abnormal decay behaviour seen as a sudden increase in the decay...

  7. Time structure measurement of the storage ring with the time-resolved X-ray excited optical luminescence method at SSRF

    OpenAIRE

    Zhaohong, Zhang; Zheng, Jiang; Song, Xue; Lifang, Zheng

    2014-01-01

    Measuring the time structure of the storage ring on the sample spot inside the experimental hutch is a foundational step during the time-resolved experiments using the pulsed synchrotron X-rays with the time structure defined by the storage ring. In this work, the method of time-resolved X-ray excited optical luminescence was designed and implemented to do the measurement. This method is based on the principle of time-correlated single photon counting techniques. The measurement system consis...

  8. Optically stimulated luminescence of ZnO obtained by thermal treatment of ZnS chemically synthesized; Luminiscencia opticamente estimulada de ZnO obtenido por tratamiento termico de ZnS sintetizado quimicamente

    Energy Technology Data Exchange (ETDEWEB)

    Cruz V, C.; Burruel I, S.E.; Orante B, V.R.; Grijalva M, H.; Perez S, R.; Bernal, R. [Universidad de Sonora, A.P. 130, Hermosillo (Mexico)

    2005-07-01

    In this work, we report the optically stimulated luminescence (OSL) dosimetry of new nano phosphors of ZnO obtained by thermal annealing of chemically synthesized ZnS powder. The synthesized ZnS nano powder was compressed in order to form pellet shaped pellets, which were afterwards subjected to a thermal annealing at 700 C during 24 h under air atmosphere. X-ray diffraction (XRD) patterns and energy-disperse X-ray Spectrometry (EDS) analyses confirmed the transformation of ZnS to ZnO. Samples were exposed to several doses of beta radiation up to 600 Gy, and the optically stimulated luminescence with 470 nm wavelength light was recorded as a function of dose. The intensity of the OSL signal increases by increasing dose, for what it is concluded that these new phosphor materials are suitable to be used in optically stimulated luminescence dosimetry. (Author)

  9. Improved differentiation between luminescence decay components by use of time-resolved optical activity measurements and selective lifetime modulation.

    Science.gov (United States)

    Schauerte, J A; Gafni, A; Steel, D G

    1996-01-01

    The analysis of luminescence decay experiments from proteins is typically modeled as a combination of independent first-order decay functions. However, Poisson noise in the photon counting experiment limits the ability of this approach to resolve decay components from separate lumiphores with similar lifetimes. To provide further differentiation, we incorporate time-resolved circular polarization of luminescence, an additional independent observable, into the analysis. In the simplest case, for example, each lumiphore's chirality is assumed to be time independent and is determined by the position of the lumiphore with respect to the surrounding chiral environment within the protein. In this paper, we describe the analysis of simultaneously recorded time-resolved luminescence and circularly polarized luminescence data to obtain improved temporal resolution. When combined with selective dynamic luminescence quenching, in a model system comprising a mixture of Tb/transferrin and Tb/conalbumin, we demonstrate resolution between two decay components with a lifetime difference of 7% and a difference in emission anisotropy of 5 X 10(-2). Evidence for the improved discrimination is further demonstrated by the increase in curvature of the chi 2 surface that results from the additional information. PMID:8785358

  10. Stable scalable control of soliton propagation in broadband nonlinear optical waveguides

    Science.gov (United States)

    Peleg, Avner; Nguyen, Quan M.; Huynh, Toan T.

    2017-02-01

    We develop a method for achieving scalable transmission stabilization and switching of N colliding soliton sequences in optical waveguides with broadband delayed Raman response and narrowband nonlinear gain-loss. We show that dynamics of soliton amplitudes in N-sequence transmission is described by a generalized N-dimensional predator-prey model. Stability and bifurcation analysis for the predator-prey model are used to obtain simple conditions on the physical parameters for robust transmission stabilization as well as on-off and off-on switching of M out of N soliton sequences. Numerical simulations for single-waveguide transmission with a system of N coupled nonlinear Schrödinger equations with 2 ≤ N ≤ 4 show excellent agreement with the predator-prey model's predictions and stable propagation over significantly larger distances compared with other broadband nonlinear single-waveguide systems. Moreover, stable on-off and off-on switching of multiple soliton sequences and stable multiple transmission switching events are demonstrated by the simulations. We discuss the reasons for the robustness and scalability of transmission stabilization and switching in waveguides with broadband delayed Raman response and narrowband nonlinear gain-loss, and explain their advantages compared with other broadband nonlinear waveguides.

  11. Stable optical spring in the Advanced LIGO detector with unbalanced arms and in the Michelson-Sagnac interferometer

    Science.gov (United States)

    Vostrosablin, Nikita; Vyatchanin, Sergey P.

    2014-03-01

    Optical rigidity in the Advanced LIGO gravitational-wave detector, operated on the dark port regime, is unstable. We show that the same interferometer with excluded symmetric mechanical mode but with unbalanced arms allows us to get stable optical spring for the antisymmetric mechanical mode. The arm detuning necessary to get stability is shown to be a small one—it corresponds to small power in the signal port. We show that stable optical spring may be also obtained in the Michelson-Sagnac interferometer with both power and signal recycling mirrors and unbalanced arms.

  12. 40-$\\mu$J passively CEP-stable seed source for ytterbium-based high-energy optical waveform synthesizers

    OpenAIRE

    Cankaya, Huseyin; Calendron, Anne-Laure; Zhou, Chun; Chia, Shih-Hsuan; Muecke, Oliver D.; Cirmi, Giovanni; Kärtner, Franz X.

    2016-01-01

    We demonstrate experimentally for the first time a ~40-µJ two-octave-wide passively carrier-envelope phase (CEP)-stable parametric front-end for seeding an ytterbium (Yb)-pump-based, few-optical-cycle, high-energy optical parametric waveform synthesizer. The system includes a CEP-stable white-light continuum and two-channel optical parametric chirped pulse amplifiers (OPCPAs) in the near- and mid-infrared spectral regions spanning altogether a two-octave-wide spectrum driven by a regenerative...

  13. Temperature lags of luminescence measurements in a commercial luminescence reader

    Energy Technology Data Exchange (ETDEWEB)

    Kitis, George [Aristotle University of Thessaloniki, Nuclear Physics Laboratory, 54124 Thessaloniki (Greece); Kiyak, Nafiye G. [ISIK University, Faculty of Science and Arts, Physics Department, Sile, 34980 Istanbul (Turkey); Polymeris, George S., E-mail: gspolymeris@ankara.edu.tr [Ankara University, Institute of Nuclear Sciences, Beşevler, 06100 Ankara (Turkey)

    2015-09-15

    The temperature recorded in thermoluminescence and optically stimulated luminescence equipments is not the temperature of the sample but that of the heating element on which the thermocouple is attached. Depending upon the rate of heating, a temperature difference appears between the samples and the heating element, termed as temperature lag, which could have serious effects on the curve shapes and trapping parameters. In the present work the temperature lag effect is studied in a newly developed luminescence equipment measuring both thermoluminescence and optically stimulated luminescence. It is found that the temperature lag could be large for heating rates above 2 K/s and it is strongly dependent upon the sample holder. A simple approximation method is proposed in order to both predict as well as correct for temperature lag effects in luminescence measurements.

  14. Stable optical trapping and sensitive characterization of nanostructures using standing-wave Raman tweezers

    Science.gov (United States)

    Wu, Mu-ying; Ling, Dong-xiong; Ling, Lin; Li, William; Li, Yong-qing

    2017-01-01

    Optical manipulation and label-free characterization of nanoscale structures open up new possibilities for assembly and control of nanodevices and biomolecules. Optical tweezers integrated with Raman spectroscopy allows analyzing a single trapped particle, but is generally less effective for individual nanoparticles. The main challenge is the weak gradient force on nanoparticles that is insufficient to overcome the destabilizing effect of scattering force and Brownian motion. Here, we present standing-wave Raman tweezers for stable trapping and sensitive characterization of single isolated nanostructures with a low laser power by combining a standing-wave optical trap with confocal Raman spectroscopy. This scheme has stronger intensity gradients and balanced scattering forces, and thus can be used to analyze many nanoparticles that cannot be measured with single-beam Raman tweezers, including individual single-walled carbon nanotubes (SWCNT), graphene flakes, biological particles, SERS-active metal nanoparticles, and high-refractive semiconductor nanoparticles. This would enable sorting and characterization of specific SWCNTs and other nanoparticles based on their increased Raman fingerprints. PMID:28211526

  15. Stable structure and optical properties of fused silica with NBOHC-E‧ defect

    Science.gov (United States)

    Lu, Peng-Fei; Wu, Li-Yuan; Yang, Yang; Wang, Wei-Zheng; Zhang, Chun-Fang; Yang, Chuang-Hua; Su, Rui; Chen, Jun

    2016-08-01

    First-principles method is used to simulate the stable structure and optical properties of a 96-atom fused silica. The preferable structure of NBOHC-E‧ (non-bridging oxygen hole center (NBOHC) and E‧ center) pair defect is predicted to be located at 2.4 Å for the Si-O bond length. The quasi-particle G0W0 calculations are performed and an accurate band gap is obtained in order to calculate the optical absorption properties. With the stretching of the Si1-O1 bond, an obvious redshift can be observed in the absorption spectrum. In the case of NBOHC-E‧ pair, the p-orbital DOS of Si1 atom will shift to the conduction band. Two obvious absorption peaks can be observed in the absorption spectrum. The calculation reproduced the peak positions of the well-known optical absorption bands. Project supported by the National Basic Research Program of China (Grant No. 2014CB643900), the Open Fund of IPOC (BUPT), the Open Program of State Key Laboratory of Functional Materials for Informatics, the National Natural Science Foundation for Theoretical Physics Special Fund “Cooperation Program” (Grant No. 11547039), and Shaanxi Provincial Institute of Scientific Research Plan Projects, China (Grant No. SLGKYQD2-05).

  16. Fabrication of thermally stable and cost-effective polymeric waveguide for optical printed-circuit board.

    Science.gov (United States)

    Kim, Do-Won; Ahn, Seung Ho; Cho, In-Kui; Im, Dong-Min; Shorab Muslim, Shirazy Md; Park, Hyo-Hoon

    2008-10-13

    A thermally stable polymeric optical waveguide has been fabricated using ultraviolet (UV)-curable epoxy resins for the core and clad materials. A simple and cost-effective fabrication method that uses reusable polydimethylsiloxane (PDMS) masters has been developed. The 12-channel under-clad layer of the UV-cured epoxy was prepared using a PDMS master whose embossed channels had been fabricated by a polycarbonate (PC) secondary master. The thermal stability of the fabricated waveguide was tested at 200 degrees C for one hour. The optical waveguide was not damaged physically by thermal stress. Propagation losses detected by a cut-back method were 0.16 dB/cm and 0.26 dB/cm, respectively, before and after the thermal stability test at 850 nm. Loss increase after the thermal treatment can be attributed to the formation of the absorbing and scattering sources. This waveguide can be applied for areas that require thermal stability such as an optical printed-circuit board.

  17. Stable optical trapping and sensitive characterization of nanostructures using standing-wave Raman tweezers

    Science.gov (United States)

    Wu, Mu-Ying; Ling, Dong-Xiong; Ling, Lin; Li, William; Li, Yong-Qing

    2017-02-01

    Optical manipulation and label-free characterization of nanoscale structures open up new possibilities for assembly and control of nanodevices and biomolecules. Optical tweezers integrated with Raman spectroscopy allows analyzing a single trapped particle, but is generally less effective for individual nanoparticles. The main challenge is the weak gradient force on nanoparticles that is insufficient to overcome the destabilizing effect of scattering force and Brownian motion. Here, we present standing-wave Raman tweezers for stable trapping and sensitive characterization of single isolated nanostructures with a low laser power by combining a standing-wave optical trap with confocal Raman spectroscopy. This scheme has stronger intensity gradients and balanced scattering forces, and thus can be used to analyze many nanoparticles that cannot be measured with single-beam Raman tweezers, including individual single-walled carbon nanotubes (SWCNT), graphene flakes, biological particles, SERS-active metal nanoparticles, and high-refractive semiconductor nanoparticles. This would enable sorting and characterization of specific SWCNTs and other nanoparticles based on their increased Raman fingerprints.

  18. Angular dependence of dose sensitivity of nanoDot optically stimulated luminescent dosimeters in different radiation geometries

    Energy Technology Data Exchange (ETDEWEB)

    Jursinic, Paul A., E-mail: pjursinic@wmcc.org [West Michigan Cancer Center, 200 North Park Street, Kalamazoo, Michigan 49007 (United States)

    2015-10-15

    Purpose: A type of in vivo dosimeter, an optically stimulated luminescent dosimeter, OSLD, may have dose sensitivity that depends on the angle of incidence of radiation. This work measures how angular dependence of a nanoDot changes with the geometry of the phantom in which irradiation occurs and with the intrinsic structure of the nanoDot. Methods: The OSLDs used in this work were nanoDot dosimeters (Landauer, Inc., Glenwood, IL), which were read with a MicroStar reader (Landauer, Inc., Glenwood, IL). Dose to the OSLDs was delivered by 6 MV x-rays. NanoDots with various intrinsic sensitivities were irradiated in numerous phantoms that had geometric shapes of cylinders, rectangles, and a cube. Results: No angular dependence was seen in cylindrical phantoms, cubic phantoms, or rectangular phantoms with a thickness to width ratio of 0.3 or 1.5. An angular dependence of 1% was observed in rectangular phantoms with a thickness to width of 0.433–0.633. A group of nanoDots had sensitive layers with mass density of 2.42–2.58 g/cm{sup 3} and relative sensitivity of 0.92–1.09 and no difference in their angular dependence. Within experimental uncertainty, nanoDot measurements agree with a parallel-plate ion chamber at a depth of maximum dose. Conclusions: When irradiated in cylindrical, rectangular, and cubic phantoms, nanoDots show a maximum angular dependence of 1% or less at an incidence angle of 90°. For a sample of 78 new nanoDots, the range of their relative intrinsic sensitivity is 0.92–1.09. For a sample of ten nanoDots, on average, the mass in the sensitive layer is 73.1% Al{sub 2}O{sub 3}:C and 26.9% polyester. The mass density of the sensitive layer of a nanoDot disc is between 2.42 and 2.58 g/cm{sup 3}. The angular dependence is not related to Al{sub 2}O{sub 3}:C loading of the nanoDot disc. The nanoDot at the depth of maximum dose has no more angular dependence than a parallel-plate ion chamber.

  19. High resolution shallow geologic characterization of a late Pleistocene eolian environment using ground penetrating radar and optically stimulated luminescence techniques: North Carolina, USA

    Science.gov (United States)

    Mallinson, D.; Mahan, S.; Moore, Christine

    2008-01-01

    Geophysical surveys, sedimentology, and optically-stimulated luminescence age analyses were used to assess the geologic development of a coastal system near Swansboro, NC. This area is a significant Woodland Period Native American habitation and is designated the "Broad Reach" archaeological site. 2-d and 3-d subsurface geophysical surveys were performed using a ground penetrating radar system to define the stratigraphic framework and depositional facies. Sediment samples were collected and analyzed for grain-size to determine depositional environments. Samples were acquired and analyzed using optically stimulated luminescence techniques to derive the depositional age of the various features. The data support a low eolian to shallow subtidal coastal depositional setting for this area. Li-DAR data reveal ridge and swale topography, most likely related to beach ridges, and eolian features including low-relief, low-angle transverse and parabolic dunes, blowouts, and a low-relief eolian sand sheet. Geophysical data reveal dominantly seaward dipping units, and low-angle mounded features. Sedimentological data reveal mostly moderately-well to well-sorted fine-grained symmetrical to coarse skewed sands, suggesting initial aqueous transport and deposition, followed by eolian reworking and bioturbation. OSL data indicate initial coastal deposition prior to ca. 45,000 yBP, followed by eolian reworking and low dune stabilization at ca. 13,000 to 11,500 yBP, and again at ca. 10,000 yBP (during, and slightly after the Younger Dryas chronozone).

  20. System for X-Ray excited optical luminescence (XEOL) measurements; Sistema para realizacao de medidas de luminescencia com excitacao por raios X

    Energy Technology Data Exchange (ETDEWEB)

    Cebim, Marco Aurelio; Oliveira, Higor Henrique de Souza; Barelli, Nilso; Davolos, Marian Rosaly [UNESP, Araraquara, SP (Brazil). Inst. de Quimica. Dept. de Quimica Geral e Inorganica

    2011-07-01

    In this work is presented a versatile system for X-ray excited optical luminescence (XEOL) measurements. The apparatus was assembled from a sample holder connected to an optical fiber responsibly for the acquisition of the scintillation signal. The spectrum is registered with a CCD coupled in a spectrograph provided with diffraction gratings. The system performance was analyzed by exciting GdAlO3:Eu{sup 3+} 3.0 at.% with X-rays from a diffractometer and measuring the emission spectra. The system can be used to obtain precise and reliable spectroscopic properties of samples with various conformations without the loss of the required safety when dealing with ionizing radiations. (author)

  1. Controlling plasmon-enhanced luminescence

    NARCIS (Netherlands)

    Mertens, H.

    2007-01-01

    Plasmons are collective oscillations of the free electrons in a metal or an ionized gas. Plasmons dominate the optical properties of noble-metal nanoparticles, which enables a variety of applications. This thesis focuses on plasmon-enhanced luminescence of silicon quantum dots (Si QDs) and optically

  2. Development and characterization of thermally stable electro-optic polymers and devices (Presentation Recording)

    Science.gov (United States)

    Otomo, Akira; Aoki, Isao; Yamada, Chiyumi; Yamada, Toshiki

    2015-10-01

    Electro-optic (EO) polymers are key materials for next generation optical communications not only in wide area network but also in local area and storage area network because EO polymer modulator can be operated at fast speed more than 100 GHz with low energy consumption and can be miniaturized in combination with silicon photonics. In practical applications, thermal stability is one of the important issues to be considered for developing EO polymers. Since EO activity of the polymer is proportional to dipole orientation factor of the EO moieties, electric field assisted poling around glass transition temperature (Tg) of the polymer is necessary. However, the poled order of the molecules relaxes gradually at finite temperature, and then EO activity decreases after long period of time. We have successfully developed thermally stable EO polymers that have high-Tg up to 180 °C. They show excellent thermal stability with the Telcordia thermal test. Thermal stability is also characterized by thermally stimulated depolarization current (TSDC) measurement. Analyzing the TSDC, we can estimate the activation energy and relaxation time of polarization at any temperature. We will discuss thermal stability of the high-Tg EO polymers and devices.

  3. Fabrication and Optimization of Stable, Optically Transparent, and Reusable pH-Responsive Silk Membranes

    Science.gov (United States)

    Toytziaridis, Andreas; Dicko, Cedric

    2016-01-01

    The fabrication of silk-based membranes that are stable, optically transparent and reusable is yet to be achieved. To address this bottleneck we have developed a method to produce transparent chromogenic silk patches that are optically responsive to pH. The patches were produced by blending regenerated silk fibroin (RSF), Laponite RD (nano clay) and the organic dyes neutral red and Thionine acetate. The Laponite RD played a central role in the patch mechanical integrity and prevention of dye leaching. The process was optimized using a factorial design to maximize the patch response to pH by UV absorbance and fluorescence emission. New patches of the optimized protocol, made from solutions containing 125 μM neutral red or 250 μM of Thionine and 15 mg/mL silk, were further tested for operational stability over several cycles of pH altering. Stability, performance, and reusability were achieved over the tested cycles. The approach could be extended to other reporting molecules or enzymes able to bind to Laponite. PMID:27854303

  4. Fabrication and Optimization of Stable, Optically Transparent, and Reusable pH-Responsive Silk Membranes

    Directory of Open Access Journals (Sweden)

    Andreas Toytziaridis

    2016-11-01

    Full Text Available The fabrication of silk-based membranes that are stable, optically transparent and reusable is yet to be achieved. To address this bottleneck we have developed a method to produce transparent chromogenic silk patches that are optically responsive to pH. The patches were produced by blending regenerated silk fibroin (RSF, Laponite RD (nano clay and the organic dyes neutral red and Thionine acetate. The Laponite RD played a central role in the patch mechanical integrity and prevention of dye leaching. The process was optimized using a factorial design to maximize the patch response to pH by UV absorbance and fluorescence emission. New patches of the optimized protocol, made from solutions containing 125 μM neutral red or 250 μM of Thionine and 15 mg/mL silk, were further tested for operational stability over several cycles of pH altering. Stability, performance, and reusability were achieved over the tested cycles. The approach could be extended to other reporting molecules or enzymes able to bind to Laponite.

  5. Middle-Late Holocene earthquake history of the Gyrtoni Fault, Central Greece: Insight from optically stimulated luminescence (OSL) dating and paleoseismology

    Science.gov (United States)

    Tsodoulos, Ioannis M.; Stamoulis, Konstantinos; Caputo, Riccardo; Koukouvelas, Ioannis; Chatzipetros, Alexandros; Pavlides, Spyros; Gallousi, Christina; Papachristodoulou, Christina; Ioannides, Konstantinos

    2016-09-01

    The south-dipping Gyrtoni Fault defines the northeastern boundary of the Middle-Late Quaternary Tyrnavos Basin, Central Greece. The recognition and recent tectonic activity of the fault were previously based on mapping, remote sensing analyses and electrical resistivity tomography studies. To understand the Holocene seismotectonic behavior of the Gyrtoni Fault we excavated two paleoseismological trenches. To estimate the timing of past earthquakes using luminescence dating, we obtained twenty five fluvial-colluvial sediment and pottery samples from both the upthrown and the downthrown fault blocks. We applied the Optically Stimulated Luminescence (OSL) dating to coarse grain quartz using the single-aliquot regenerative-dose (SAR) protocol. Our investigations of luminescence characteristics using various tests confirmed the suitability of the material for OSL dating. We found that the estimated OSL ages were internally consistent and agreed well with the available stratigraphical data, archaeological evidence and radiocarbon dates. The performed paleoseismological analysis emphasized the occurrence of three surface faulting events in a time span between 1.42 ± 0.06 ka and 5.59 ± 0.13 ka. Also, we recognized an earlier faulting event (fourth) has been also recognized to be older than 5.59 ± 0.13 ka. The mean throw per event value of 0.50-0.60 m could correspond to a ca. Mw 6.5 earthquake. An average fault slip rate of 0.41 ± 0.01 mm/a and an average recurrence time of 1.39 ± 0.14 ka were also estimated. Our results suggest that the elapsed time from the most recent event (minimum age 1.42 ± 0.06 ka) is comparable with the mean return period.

  6. Nanoparticules multifonctionnelles de vanadate dopées aux terres rares : Marqueurs luminescents, détecteurs d'oxydant et agent de contraste pour l'imagerie à résonance magnétique

    OpenAIRE

    Schoeffel, Markus

    2012-01-01

    Multimodal imaging techniques are of great interest due to the wealth of information they provide. This thesis is devoted to the development and characterization of nanoparticles which can be applied as luminescent probes, for oxidant detection and as contrast agents in magnetic resonance imaging. The work is based on previous studies on Y0.6Eu0.4VO4 nanoparticles which show strong, non-blinking and stable luminescence. Time and space resolved optical oxidant detection is feasible after rever...

  7. High temperature luminescence of Dy3+ in crystalline silicon in the optical communication and eye-safe spectral regions.

    Science.gov (United States)

    Lourenço, M A; Mustafa, Z; Ludurczak, W; Wong, L; Gwilliam, R M; Homewood, K P

    2013-09-15

    We report on photoluminescence in the 1.3 and 1.7 μm spectral ranges in silicon doped with dysprosium. This is attributed to the Dy3+ internal transitions between the second Dy3+ excited state and the ground state, and between the third Dy3+ excited state and the ground state. Luminescence is achieved by Dy implantation into Si substrates codoped with boron, to form dislocation loops, and show a strong dependence on fabrication process. The spectra consist of several sharp lines with the strongest emission at 1736 nm, observed up to 200 K. No Dy3+ luminescence is observed in samples without B codoping, showing the paramount importance of dislocation loops to enable the Dy emission.

  8. Optical, luminescence and thermal properties of radiopure ZnMoO{sub 4} crystals used in scintillating bolometers for double beta decay search

    Energy Technology Data Exchange (ETDEWEB)

    Chernyak, D.M. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Centre de Sciences Nucléaires et de Sciences de la Matière, 91405 Orsay (France); Danevich, F.A. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Degoda, V.Ya.; Dmitruk, I.M. [Kyiv National Taras Shevchenko University, MSP 03680 Kyiv (Ukraine); Ferri, F. [Dipartimento di Scienza e Alta Tecnologia dell' Università dell' Insubria, Como I-22100 (Italy); Galashov, E.N. [Nikolaev Institute of Inorganic Chemistry, 630090 Novosibirsk (Russian Federation); Giuliani, A., E-mail: Andrea.Giuliani@csnsm.in2p3.fr [Centre de Sciences Nucléaires et de Sciences de la Matière, 91405 Orsay (France); Dipartimento di Scienza e Alta Tecnologia dell' Università dell' Insubria, Como I-22100 (Italy); Sezione INFN di Milano-Bicocca, I-20126 Italy (Italy); Ivanov, I.M. [Nikolaev Institute of Inorganic Chemistry, 630090 Novosibirsk (Russian Federation); Kobychev, V.V. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Mancuso, M.; Marnieros, S. [Centre de Sciences Nucléaires et de Sciences de la Matière, 91405 Orsay (France); Dipartimento di Scienza e Alta Tecnologia dell' Università dell' Insubria, Como I-22100 (Italy); Mokina, V.M. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Nones, C.; Olivieri, E. [Service de Physique des Particules, CEA-Saclay, F-91191 Gif sur Yvette (France); Pessina, G. [Sezione INFN di Milano-Bicocca, I-20126 Italy (Italy); Rusconi, C. [Dipartimento di Scienza e Alta Tecnologia dell' Università dell' Insubria, Como I-22100 (Italy); Sezione INFN di Milano-Bicocca, I-20126 Italy (Italy); and others

    2013-11-21

    Zinc molybdate (ZnMoO{sub 4}) crystals are an excellent candidate material to fabricate scintillating bolometers for the study of neutrinoless double beta decay of {sup 100}Mo, provided that the crystal quality meets strict optical, thermal and radiopurity requirements. This paper addresses the characterization of improved crystalline samples grown by the low-thermal-gradient Czochralski technique. Transmittance measurements confirm significant improvement of the material with respect to previously developed samples. Luminescence properties (emission spectra, dependence of intensity on temperature, thermally stimulated luminescence and phosphorescence) have been studied under X-ray excitation from liquid-helium to room temperature. The index of refraction was measured in the wavelength interval 406–655 nm. Samples of ZnMoO{sub 4} crystals with masses of 5.07 g and 23.8 g were operated as scintillating bolometers at temperatures below 30 mK, with simultaneous detection of scintillation and heat signals, confirming an excellent alpha/beta rejection power. Background measurements allowed encouraging radiopurity level estimations. The light collection from ZnMoO{sub 4} scintillators was Monte Carlo simulated, analysing different crystal size, shape and surface properties and different photodetector sizes.

  9. Violet stimulated luminescence: geo- or thermochronometer?

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Guralnik, Benny; Porat, N.

    2015-01-01

    The method of quartz optically stimulated luminescence (OSL) dating is widely used, but generally limited to the past ~0.1 million years (Ma) due to early saturation of the desired signal. Violet stimulated luminescence (VSL) of quartz has previously been shown as a promising alternative...

  10. Violet stimulated luminescence: geo- or thermochronometer?

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Guralnik, Benny; Porat, N.;

    2015-01-01

    The method of quartz optically stimulated luminescence (OSL) dating is widely used, but generally limited to the past ~0.1 million years (Ma) due to early saturation of the desired signal. Violet stimulated luminescence (VSL) of quartz has previously been shown as a promising alternative...

  11. Kinetics of infrared stimulated luminescence from feldspars

    DEFF Research Database (Denmark)

    Jain, Mayank; Sohbati, Reza; Guralnik, Benny;

    2015-01-01

    thermal and optical, of the infrared stimulated luminescence signal from feldspar. Based on the application of this model, it is concluded that different infra-red stimulated luminescence emissions (UV, blue, yellow and far-red) follow the same kinetics, and, therefore, involve participation of the same...

  12. Synthesis, characterization and optical studies of highly luminescent ZnS nanoparticles associated with hypromellose matrix as a green and novel stabilizer.

    Science.gov (United States)

    Tiwari, Ashish; Khan, S A; Kher, R S; Dhoble, S J

    2014-09-01

    ZnS nanoparticles stabilized by a carbohydrate-based matrix, hypromellose (hydroxypropyl methylcellulose) were prepared via a wet chemical method. The nanocomposite was characterized by X-ray diffraction, transmission electon microscopy and Fourier transform infrared spectroscopy. X-Ray diffraction patterns revealed a zinc blende structure. Thermogravimetric analysis suggested that polymer attached to the surface decomposes at 700 °C. Absorption measurements were carried out and calculation of the diameter polydispersity index (DPI) suggests the formation of monodisperse nanoparticles. The optical properties of the as-prepared samples were studied by UV/vis spectroscopy and steady-state photoluminescence (PL) spectroscopy. The PL studies indicate the applicability of these nanoparticles as biocompatible sensors or luminescence markers in future.

  13. Retrospective assessment of environmental dose rates using optically stimulated luminescence from Al2O3:C and quartz

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Banerjee, D.; Jungner, H.;

    1999-01-01

    As part of our continuing work on assessing the usefulness of natural and artificial dosemeters in retrospective accident dosimetry, the natural photon dose rates within bricks have been measured using the optically stimulated luminescence (OSL) from Al2O3:C single crystal dosemeters. These were...... placed in bricks in house walls for two weeks to integrate the environmental dose rates after which their OSL signals were measured. These results were compared with (1) OSL measurements of quartz samples extracted from the bricks and (2) dose rates determined from laboratory measurements of the natural...... crystals distributed in holes across a brick section and (2) quartz (extracted from the matrix of the brick) taken across the same section. These were compared with typical depth dose profiles found in bricks collected in the Chernobyl accident area and demonstrate retrospectively that the average energy...

  14. Investigation on heat sterilization of BeO-detectors for optical stimulated luminescence (OSL); Untersuchungen zur Hitzesterilisation von BeO-Detektoren fuer die optisch stimulierte Lumineszenz (OSL)

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, W.; Piehler, S.; Burgkhardt, B. [Duale Hochschule Baden-Wuerttemberg (DHBW), Karlsruhe (Germany). Sicherheitswesen

    2015-07-01

    BeO-Detectors show a high thermal stability when optically stimulated luminescence is measured. With respect to steam sterilization of extremity dosimeters in medicine this paper investigates the effect of heat treatments on the response at commonly used temperatures of 121 C and 134 C. A commercial OSL-dosimetry system with BeO detectors uses dosimeter trays made of none-heat resistant plastic. The detectors are welded with the tray. Constructing a tray which allowed the detectors to be taken out was essential to perform heat treatments in heat resistant holders. Up to 20 simulated heat treatments at 121 C as well as irradiations of one dosimeter during one month resulted in small changes of the detector response, within ±10%. Similar results were shown by one irradiation and one summed up heat treatment at 121 C and 134 C. This is also true for the characteristics of the response vs. time of the heat treatment.

  15. Dating human occupation at Toca do Serrote das Moendas, São Raimundo Nonato, Piauí-Brasil by electron spin resonance and optically stimulated luminescence.

    Science.gov (United States)

    Kinoshita, Angela; Skinner, Anne R; Guidon, Niede; Ignacio, Elaine; Felice, Gisele Daltrini; Buco, Cristiane de A; Tatumi, Sonia; Yee, Márcio; Figueiredo, Ana Maria Graciano; Baffa, Oswaldo

    2014-12-01

    Excavation of Toca do Serrote das Moendas, in Piauí state, Brazil revealed a great quantity of fossil wild fauna associated with human remains. In particular, fossils of a cervid (Blastocerus dichotomus) were found, an animal frequently pictured in ancient rock wall paintings. In a well-defined stratum, two loose teeth of this species were found in close proximity to human bones. The teeth were independently dated by electron spin resonance (ESR) in two laboratories. The ages obtained for the teeth were 29 ± 3 ka (thousands of years) and 24 ± 1 ka. The concretion layer capping this stratum was dated by optically stimulated luminescence (OSL) of the quartz grains to 21 ± 3 ka. As these values were derived independently in three different laboratories, using different methods and equipment, these results are compelling evidence of early habitation in this area.

  16. Energy levels in YPO{sub 4}:Ce{sup 3+},Sm{sup 3+} studied by thermally and optically stimulated luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Bos, Adrie J.J., E-mail: a.j.j.bos@tudelft.n [Delft University of Technology, Mekelweg 15, NL 2629 JB Delft (Netherlands); Poolton, Nigel R.J. [Delft University of Technology, Mekelweg 15, NL 2629 JB Delft (Netherlands); Institute of Maths and Physics, Aberystwyth University, Aberystwyth SY23 3BZ (United Kingdom); Wallinga, Jakob [Netherlands Centre for Luminescence Dating, Delft University of Technology, Mekelweg 15, NL 2629 JB Delft (Netherlands); Bessiere, Aurelie [Ecole Nat. Superieure de Chimie de Paris, 11 Rue P et M Curie, 75231 Paris Cedex 05 (France); Dorenbos, Pieter [Delft University of Technology, Mekelweg 15, NL 2629 JB Delft (Netherlands)

    2010-03-15

    Energy-resolved optically stimulated luminescence (OSL) spectra and thermoluminescence (TL) glow curves of a powder sample of YPO{sub 4}:Ce{sup 3+},Sm{sup 3+} were measured to investigate the nature of the trapping centre and to locate its energy level relative to the valence and conduction bands of the YPO{sub 4} host. The high-temperature glow peak could unequivocally be assigned to Sm{sup 2+} (thus Sm{sup 3+} acts as an electron trap). The trap depth of this centre, as derived from the OSL excitation spectra, is in good agreement with the Dorenbos model prediction. The OSL excitation spectra also reveal excited states of Sm{sup 2+} well below the conduction band. These excited states produce a broadening of the high-temperature TL glow peak and also cause the activation energy determined by the Hoogenstraten method to underestimate the trap depth.

  17. Thermoluminescence and optically stimulated luminescence properties of the 0.5P₂O₅-xBaO-(0.5-x)Li₂O glass systems.

    Science.gov (United States)

    Timar-Gabor, A; Ivascu, C; Vasiliniuc, S; Daraban, L; Ardelean, I; Cosma, C; Cozar, O

    2011-05-01

    Thermoluminescence and optically stimulated luminescence properties of phosphate glasses doped with BaO and Li(2)O at various concentrations were studied. Lithium-doped glasses show a broad TL peak in the 200-300°C region with poor dosimetric characteristics. Barium-doped glasses feature at least two TL peaks, approximately at 200 and 400°C, which were attributed to Ba(2+) ions. They also produce a fast-decaying OSL signal correlated with the lower-temperature TL peak. Responses of both TL emissions to radiation doses up to 100 Gy are linear (R² >0.99). Due to its encouraging characteristics such as acceptable batch homogeneity, good measurement reproducibility and weak signal fading, the P₂O₅-xBaO glass can be considered as a candidate material for dosimetry in the high-dose range (>10 Gy).

  18. Eu2+ luminescence in strontium aluminates

    OpenAIRE

    Dutczak, D.; Juestel, T.; Ronda, C.; Meijerink, A.|info:eu-repo/dai/nl/075044986

    2015-01-01

    The luminescence properties of Eu2+ doped strontium aluminates are reported and reviewed for a variety of aluminates, viz. SrAl12O19, SrAl4O7, Sr4Al14O25, SrAl2O4 and Sr3Al2O6. The aim of the research is to investigate the role of local coordination and covalency of the aluminate host lattice, related to the Sr/Al ratio, on the optical properties of the Eu2+ ion. The UV and VUV excited luminescence spectra as well as luminescence decay curves were recorded to characterize the luminescence pro...

  19. Optical absorption and luminescence characteristics of Dy{sup 3+} doped Zinc Alumino Bismuth Borate glasses for lasing materials and white LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Swapna, K.; Mahamuda, Sk. [Department of Physics, K.L. University, Green Fields, Vaddeswaram 522502, A.P. (India); Srinivasa Rao, A., E-mail: drsrallam@yahoo.co.in [Department of Physics, K.L. University, Green Fields, Vaddeswaram 522502, A.P. (India); Department of Applied Physics, Delhi Technological University, Delhi 110042 (India); Jayasimhadri, M. [Department of Applied Physics, Delhi Technological University, Delhi 110042 (India); Sasikala, T.; Rama Moorthy, L. [Department of Physics, S.V. University, Tirupathi 517502, A.P. (India)

    2013-07-15

    Good optical quality Dy{sup 3+} doped Zinc Alumino Bismuth Borate (ZnAlBiB) glasses were prepared by the conventional melt quenching technique and characterized by optical absorption and luminescence studies. The glassy nature of these materials has been confirmed through XRD measurements. From the absorption spectra, the three phenomenological JO parameters Ω{sub λ} (λ=2,4 and 6) have been determined from the absorption spectral intensities by using the JO theory. Luminescence spectra were measured for different concentrations of Dy{sup 3+} ions doped glasses by exciting the glasses at 387 nm. The intensity of Dy{sup 3+} emission spectra increases from 0.5 mol% to 1 mol % and beyond 1 mol % the concentration quenching is observed. The suitable concentration of Dy{sup 3+} ions for ZnAlBiB glassy material to act as good lasing material has been discussed by measuring the branching ratios and emission cross-sections for two strong emission transitions such as {sup 4}F{sub 9/2}→{sup 6}H{sub 15/2} and {sup 4}F{sub 9/2}→{sup 6}H{sub 13/2} observed in visible region. By exciting these glassy materials at various excitation wavelengths in n-UV region, the CIE chromaticity coordinates were evaluated for the two sharp emissions observed in blue ({sup 4}F{sub 9/2}→{sup 6}H{sub 15/2}) and yellow ({sup 4}F{sub 9/2}→{sup 6}H{sub 13/2}) regions to understand the suitability of these materials for white light generation. -- Highlights: ► Successfully synthesized the transparent Zinc Alumino Bismuth Borate glasses. ► Measured the absorption and luminescence properties. ► Discussed the spectroscopic properties by using Judd–Ofelt analysis for ZnAlBiB glasses. ► Finally, suitability of these glasses for lasers and white LEDs has been discussed.

  20. Handbook of luminescent semiconductor materials

    CERN Document Server

    Bergman, Leah

    2011-01-01

    Photoluminescence spectroscopy is an important approach for examining the optical interactions in semiconductors and optical devices with the goal of gaining insight into material properties. With contributions from researchers at the forefront of this field, Handbook of Luminescent Semiconductor Materials explores the use of this technique to study semiconductor materials in a variety of applications, including solid-state lighting, solar energy conversion, optical devices, and biological imaging. After introducing basic semiconductor theory and photoluminescence principles, the book focuses

  1. Thermally and optically stimulated luminescence in long persistent orthorhombic strontium aluminates doped with Eu, Dy and Eu, Nd

    Science.gov (United States)

    Zúñiga-Rivera, N. J.; Salas-Castillo, P.; Chernov, V.; Díaz-Torres, L. A.; Meléndrez, R.; García-Gutierrez, R.; Carrillo-Torres, R. C.; Barboza-Flores, M.

    2017-05-01

    The long persistent luminescence, thermoluminescence (TL) and IR stimulated luminescence properties of two orthorhombic strontium aluminates (Sr4Al14O25) co-doped with Eu2+, Dy3+ and Eu2+, Nd3+ exposed to beta radiation is reported. The phosphors were synthesized by the combustion method followed by a post-annealing treatment under a reductive carbon atmosphere. Photoluminescence emission spectra of both phosphors are typical for emission of Eu2+ ions with 7-fold and 10-fold coordination in Sr4Al14025 and consist of the main band at 480 nm and a weak band between 390 and 440 nm. After exposure to beta radiation the Sr4Al14025:Eu2+,Dy3+ phosphor exhibits two strongly overlapped TL peaks at about 70 and 100 °C while the low temperature TL of the Sr4Al14025:Eu2+,Nd3+ phosphor consist of two well separated peaks with maxima at about 60 and 130 °C. Additionally, both phosphors exhibit a weak TL between 180 and 400 °C. The traps responsible for the low temperature TL peaks are the Dy3+ and Nd3+ centers situated in two different Sr sites with 7-fold and 10-fold coordination. The thermal emptying of the Dy and Nd filled traps creates ultra-long intense afterglow, which gradually decays with time and remains detectable after 220 h storage in dark. IR stimulation of beta irradiated phosphors creates intense IR stimulated luminescence, which is related to the release of electrons from the filled Dy and Nd traps.

  2. Luminescence sensitivity changes in quartz

    CERN Document Server

    Wintle, A G

    1999-01-01

    In the luminescence dating of sedimentary or heated quartz, some heat treatment is usually applied to the sample immediately prior to the measurement of the optically stimulated luminescence. In this paper we report experiments on a 30,000-year-old sedimentary quartz, in which we use the luminescence response to a test dose to monitor the changes in sensitivity that are caused by holding the quartz at temperatures from 160 to 280 deg. C for times from 10 s to 22 h. For an optically bleached sample, the monitoring is by both optically stimulated luminescence and the 110 deg. C TL peak; both luminescence signals are shown to have the same sensitisation (i.e. activation energy) characteristics. For natural or laboratory irradiated samples only the 110 deg. C TL peak can be used; sensitivity increases of up to a factor of 1.3 and 3 are observed for the natural and laboratory irradiated aliquots, respectively. Up to four exponential components are used to deconvolve the sensitivity change data; the dominant compon...

  3. The origin of dose distributions in fluvial sediments, and the prospect of dating single grains from fluvial deposits using optically stimulated luminescence

    CERN Document Server

    Olley, J M; Roberts, R G

    1999-01-01

    We examine the causes of the asymmetric distributions of dose observed from measurements of the optically stimulated luminescence emitted by small aliquots of fluvial quartz, and deduce that the asymmetry arises as a result of samples being composed of a mix of mainly well bleached grains with grains that were effectively unbleached at the time of deposition. We demonstrate that the shapes of the dose distributions can be used to assess the likelihood that aliquots consist only of grains that were well-bleached at the time of deposition. The more asymmetric the distribution, the greater the probability that the aliquots with the lowest dose most closely represent the true burial dose. Single grains with differing doses are present in each of the samples examined, and the population with the lowest dose gives an optical age consistent with the expected burial age. This result implies that the beta-dose heterogeneity in these deposits is small, and that the effects of micro-dosimetric variations on optical dati...

  4. Limit of detection of a fiber optics gyroscope using a super luminescent radiation source; Limite de deteccion de un giroscopio de fibra optica usando una fuente de radiacion superluminiscente

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval R, G.E. [Laboratorio de Optica Aplicada, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, 04510 Mexico D.F. (Mexico); Nikolaev, V.A. [Departamento de Optica y Radiofisica Cuantica, Universidad Estatal de Telecomunicaciones de San Petersburgo, M.A. Bonch-Bruyevich, Kanal Moika 61, Saint Petersburg 191186, (Russian Federation)

    2003-07-01

    The main objective of this work is to establish the dependence of characteristics of the fiber optics gyroscope (FOG) with respect to the parameters of the super luminescent emission source based on doped optical fiber with rare earth elements (Super luminescent Fiber Source, SFS), argument the pumping rate election of the SFS to obtain characteristics limits of the FOG sensibility. By using this type of emission source in the FOG is recommend to use the rate when the direction of the pumping signal coincide with the super luminescent signal. The most results are the proposition and argumentation of the SFS election as emission source to be use in the FOG of the phase type. Such a decision allow to increase the characteristics of the FOG sensibility in comparison with the use of luminescent source of semiconductors emission which are extensively used in the present time. The use of emission source of the SFS type allow to come closer to the threshold of the obtained sensibility limit (detection limit) which is determined with the shot noise. (Author)

  5. Advances in luminescence instrument systems

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Bulur, E.; Duller, G.A.T.

    2000-01-01

    We report on recent advances in the development of luminescence measurement systems and techniques at Riso. These include: (1) optical stimulation units based on new-generation powerful blue light (470 nm) emitting diodes providing up to 28 mW/cm(2) for OSL measurements; (2) an infrared (830 nm...

  6. Persistent Luminescence Nanophosphor Involved Near-Infrared Optical Bioimaging for Investigation of Foodborne Probiotics Biodistribution in Vivo: A Proof-of-Concept Study.

    Science.gov (United States)

    Liu, Yaoyao; Liu, Jing-Min; Zhang, Dongdong; Ge, Kun; Wang, Peihua; Liu, Huilin; Fang, Guozhen; Wang, Shuo

    2017-09-20

    Probiotics has attracted great attention in food nutrition and safety research field, but thus far there are limited analytical techniques for visualized and real-time monitoring of the probiotics when they are ingested in vivo. Herein, the optical bioimaging technique has been introduced for investigation of foodborne probiotics biodistribution in vivo, employing the near-infrared (NIR) emitting persistent luminescence nanophosphors (PLNPs) of Cr(3+)-doped zinc gallogermanate (ZGGO) as the contrast nanoprobes. The ultrabrightness, super long afterglow, polydispersed size, low toxicity, and excellent photostability and biocompatibility of PLNPs were demonstrated to be qualified as a tracer for labeling probiotics via antibody (anti-Gram positive bacteria LTA antibody) recognition as well as contrast agent for long-term bioimaging the probiotics. In vivo optical bioimaging assay showed that the LTA antibody functionalized ZGGO nanoprobes that could be efficiently tagged to the probiobics were successfully applied for real-time monitoring and nondamaged probing of the biodistribution of probiotics inside the living body after oral administration. This work presents a proof-of-concept that exploited the bioimaging methodology for real-time and nondamaged researching the foodborne probiotics behaviors in vivo, which would open up a novel way of food safety detection and nutrition investigation.

  7. Ultra-Stable Beacon Source for Laboratory Testing of Optical Tracking

    Science.gov (United States)

    Aso, Yoichi; Marka, Szabolcs; Kovalik, Joseph

    2008-01-01

    The ultra-stable beacon source (USBS) provides a laser-beam output with a very low angular jitter and can be used as an absolute angular reference to simulate a beacon in the laboratory. The laser is mounted on the top of a very short (approximately equal to 1 m) inverted pendulum (IP) with its optical axis parallel to the carbon fiber pendulum leg. The 85-cm, carbon fiber rods making up the leg are very lightweight and rigid, and are supported by a flex-joint at the bottom (see figure). The gimbal-mounted laser is a weight-adjustable load of about 1.5 kg with its center of rotation co-located with the center of percussion of the inverted pendulum. This reduces the coupling of transverse motion at the base of the pendulum to angular motion of the laser at the top. The inverted pendulum is mounted on a gimbal with its center of rotation coinciding with the pivot position of the inverted pendulum flexure joint. This reduces coupling of ground tilt at the inverted pendulum base to motion of the laser mounted at the top. The mass of the top gimbal is adjusted to give the pendulum a very low resonant frequency (approximately equal to 10 mHz) that filters transverse seismic disturbances from the ground where the base is attached. The motion of the IP is monitored by an optical-lever sensor. The laser light is reflected by the mirror on the IP, and then is detected by a quadrant photo-detector (QPD). The position of the beam spot on the QPD corresponds to the tilt of the IP. Damping of this motion is provided by two coil and magnet pairs. The bottom gimbal mount consists of two plates. The IP is mounted on the second plate. The first plate is supported by two posts through needles and can be rotated about the axis connecting the tips of the needles. The second plate hangs from the first plate and can be rotated about the axis perpendicular to the first plate. As a result, the second plate acts as a two-axis rotation stage. Its center of rotation is located at the

  8. Optically stimulated luminescence (OSL) response of Al2O3:C, BaFCl:Eu and K2Ca2(SO4)3:Eu phosphors.

    Science.gov (United States)

    Kumar, Pratik; Bahl, Shaila; Sahare, P D; Kumar, Surender; Singh, Manveer

    2015-12-01

    This paper investigates the optically stimulated luminescence (OSL) response of BaFCl:Eu and K2Ca2(SO4)3:Eu phosphors for different doses and bleaching durations. The results have also been compared with the commercially available Landauer Al2O3:C (Luxel®) dosemeter. Nanocrystalline K2Ca2(SO4)3:Eu is known to be a sensitive thermoluminescent phosphor, but its OSL response is hardly reported. At first, pellets of nanocrystalline K2Ca2(SO4)3:Eu powder were prepared by adding Teflon as a binder. Their OSL signal was compared with that of the material in pure form, i.e. without adding the binder (in 100:1 ratio). It was observed that adding the binder does not appreciably affect the OSL intensity. On comparison with the commercially available Al2O3:C from Landauer, it was found that K2Ca2(SO4)3:Eu is around 15 times less sensitive than Al2O3:C. 'Homemade' BaFCl:Eu phosphor has also been studied. The intensity of BaFCl:Eu was ∼20 times more than the standard Al2O3:C dosemeter and ∼200 times more sensitive than K2Ca2(SO4)3:Eu in the dose range of 13-200 cGy. OSL dosemeters are believed to give luminescence signal even if they are read before, i.e. multiple reading may be possible under suitable conditions after single exposure. This was also checked for all the prepared dosemeters and it was found that Al2O3:C showed the least decrease of Eu of 15 % and K2Ca2(SO4)3:Eu with 20 %. Finally, Al2O3:C and BaFCl:Eu phosphors were also studied for their optical bleaching durations to which the respective signals get completely removed so that the phosphor can be re-used. It was observed that BaFCl:Eu is bleached faster and more easily than Al2O3:C.

  9. MgO-Al2O3-ZrO2 Amorphous Ternary Composite: A Dense and Stable Optical Coating

    Science.gov (United States)

    Shaoo, Naba K.; Shapiro, Alan P.

    1998-01-01

    The process-parameter-dependent optical and structural properties of MgO-Al2O3-ZrO2 ternary mixed-composite material were investigated. Optical properties were derived from spectrophotometric measurements. The surface morphology, grain size distributions, crystallographic phases, and process- dependent material composition of films were investigated through the use of atomic force microscopy, x-ray diffraction analysis, and energy-dispersive x-ray analysis. Energy-dispersive x-ray analysis made evident the correlation between the optical constants and the process-dependent compositions in the films. It is possible to achieve environmentally stable amorphous films with high packing density under certain optimized process conditions.

  10. Transmissive grating-reflective mirror-based fiber optic accelerometer for stable signal acquisition in industrial applications

    Science.gov (United States)

    Lee, Yeon-Gwan; Kim, Dae-Hyun; Kim, Chun-Gon

    2012-05-01

    This paper discusses an applicable fiber-optic accelerometer composed of a transmissive grating panel, a reflection mirror, and two optical fibers with a separation of quarter grating pitch as transceivers that monitor the low-frequency accelerations of civil engineering structures. This sensor structure brings together the advantages of both a simple sensor structure, which leads to simplified cable design by 50% in comparison with the conventional transmission-type fiber optic accelerometer, and a stable reflected signals acquisition with repeatability in comparison to the researched grating-reflection type fiber optic accelerometer. The vibrating displacement and sinusoidal acceleration measured from the proposed fiber optic sensor demonstrated good agreement with those of a commercial laser displacement sensor and a MEMS accelerometer without electromagnetic interference. The developed fiber optic accelerometer can be used in frequency ranges below 4.0 Hz with a margin of error that is less than 5% and a high sensitivity of 5.06 rad/(m/s)2.

  11. Investigation of linear optical absorption coefficients in core-shell quantum dot (QD) luminescent solar concentrators (LSCs)

    Science.gov (United States)

    Ebrahimipour, Bahareh Alsadat; Askari, Hassan Ranjbar; Ramezani, Ali Behjat

    2016-09-01

    The interlevel absorption coefficient of CdSe/ZnS and ZnS/CdSe core-shell Quantum Dot (QD) in luminescent solar concentrators (LSCs) is reported. By considering the quantum confinement effects, the wave functions and eigenenergies of electrons in the nonperturebative system consists of a core-shell QD have been numerically calculated under the frame work of effective-mass approximation by solving a three-dimensional Schrӧdinger equation. And then the absorption coefficient is obtained under density matrix approximation considering in the polymer sheets of the concentrator including the core-shell QDs. The effect of the hetero-structure geometry upon the energy spectrum and absorption coefficient associated to interlevel transitions was also considered. The results show that the core-shell QDs can absorb the photons with higher energy in solar spectrum as compared to the inverted core-shell. And with a small shell layer diameter, the core-shell QDs produce larger linear absorption coefficients and consequently higher efficiency values, however it is inversed for inverted core-shell QDs. The work described here gives a detailed insight into the promise of QD-based LSCs and the optoelectronic devices applications.

  12. High-Temperature Thermometer Using Cr-Doped GdAlO3 Broadband Luminescence

    Science.gov (United States)

    Eldridge, Jeffrey; Chambers, Matthew

    2011-01-01

    novel since broadband luminescence emission normally shows severe thermal quenching. The tightly bound AlO6 octahedra in GdAlO3 results in a larger energy barrier to nonradiative decays than in other materials and therefore makes using broadband emission for temperature sensing possible at high temperatures. This approach results in a substantial increase in temperature capability. For example, the most commonly used Cr-doped crystal used for luminescence-based temperature measurements, ruby, has only been demonstrated up to 600 C, whereas the Cr:GdAlO3 optical thermometer under development has already been shown to exhibit useful luminescence up to 1,300 C. Because GdAlO3 is non-reactive and is stable in harsh, high-temperature environments, sensors composed of Cr:GdAlO3 will be very well suited for remote high-temperature measurements in engine or industrial environments where its intense high-temperature luminescence will stand out above significant thermal radiation background levels.

  13. Micro-modulated luminescence tomography

    CERN Document Server

    Cong, Wenxiang; Wang, Chao; Wang, Ge

    2013-01-01

    Imaging depth of optical microscopy has been fundamentally limited to millimeter or sub-millimeter due to light scattering. X-ray microscopy can resolve spatial details of few microns deeply inside a sample but the contrast resolution is still inadequate to depict heterogeneous features at cellular or sub-cellular levels. To enhance and enrich biological contrast at large imaging depth, various nanoparticles are introduced and become essential to basic research and molecular medicine. Nanoparticles can be functionalized as imaging probes, similar to fluorescent and bioluminescent proteins. LiGa5O8:Cr3+ nanoparticles were recently synthesized to facilitate luminescence energy storage with x-ray pre-excitation and the subsequently stimulated luminescence emission by visible/near-infrared (NIR) light. In this paper, we suggest a micro-modulated luminescence tomography (MLT) approach to quantify a nanophosphor distribution in a thick biological sample with high resolution. Our numerical simulation studies demonst...

  14. Thermal quenching of luminescence processes in feldspars

    DEFF Research Database (Denmark)

    Poolton, N.R.J.; Bøtter-Jensen, L.; Duller, G.A.T.

    1995-01-01

    The technique of optically stimulated luminescence has important uses in the dose evaluation of irradiated feldspars. The luminescence process involves the eviction of electrons from donor traps, charge transfer through the conduction band, and recombination at acceptor sites; each...... of these processes is, in general, thermally dependent, and leads either to enhancement or quenching of the luminescence with increasing temperature. Previous studies have measured the combined thermal activation characteristics of all three processes, and show a strong dependence on stimulation energy....... In this article, an initial attempt is made to isolate only the recombination part of the luminescence cycle, and determine its thermal characteristics separately. A Variety of luminescence transitions are examined in a range of both alkali and plagioclase feldspars; three distinct emission types are identified...

  15. Complex of heavy magnetic ions and luminescent silicon nanoparticles

    Science.gov (United States)

    Hoang, Tuan

    We study the optical properties of luminescent silicon nanoparticles in the presence of magnetic ions of iron or erbium in solution and electric biasing. Upon the introduction of the ions under zero biasing, the luminescence is enhanced to by 50%. The peak position of the nanoparticle's spectrum shifts by 10 nm. The enhancement remains stable even outside of the solvent, and under exposure to an ionizing environment, with electric eld as high as 8 MV/m exceeding the breakdown eld value of solution. We attribute the enhancement and spectral change to the formation of complex between the silicon nanoparticles and the ions. We compare these results with the computational study that was done in our group using density functional theory. The calculations yield two stable con gurations that such ion-particle complex could form, with binding energy of 0:49 eV between the ion and the nanoparticle. The complexes promise diverse applications in magnetic/optical imaging, spatially programmable deposition, spin-based memories and transistors, infrared communications, ltration, as well as interplanetary and interstellar observation and modeling.

  16. Long-persistent luminescence in the near-infrared from Nd3+-doped Sr2SnO4 for in vivo optical imaging

    Science.gov (United States)

    Kamimura, Sunao; Xu, Chao-Nan; Yamada, Hiroshi; Terasaki, Nao; Fujihala, Masayoshi

    2014-09-01

    We discovered a new near-infrared (NIR) persistent luminescent material Sr2SnO4:Nd3+, which exhibited NIR luminescence ranging from 850 to 1400 nm. Furthermore, we successfully enhanced the intensity of NIR persistent luminescence by increasing the firing temperature. The intensity of NIR persistent luminescence, which penetrates through a human finger and can be used to visualize a finger vein pattern by using a charge-coupled device camera, reached approximately 1.1 mW/m2 (λ = 900 nm) at a decay time of 10 s after ceasing the excitation. We proposed the enhancement process of the NIR persistent luminescence for Sr2SnO4:Nd3+ in conjunction with photoluminescence, absorption, thermoluminescence, and structural properties.

  17. The study on optically stimulated luminescence dosimeter based on the SrS:Eu, Sm and CaS:Eu, Sm

    Institute of Scientific and Technical Information of China (English)

    Liu Yan-Ping; Chen Zhao-Yang; Fan Yan-Wei; Ba Wei-Zhen; Gou Qi; Lu Wu; Tang Xin-Qiang; Du Yan-Zhao

    2008-01-01

    With the increasing use of nuclear energy, there is a need for a wider range of efficient dosimeters for radiation detection and assessment. There has been a tremendous growth in the development of radiation detectors and devices in the past few decades. In recent years, the development of new materials for radiation dosimetry has progressed significantly. Alkaline earth sulfides (AES) have been known for a long time as excellent and versatile phosphor materials.In the present investigation, a number of phosphor samples such as mono-, binary and ternary sulfides of alkaline earths (Ⅱa-Ⅵb) have been prepared and their TL properties have been studied with respect to exposure (x-ray) response and fading. In this paper, some results on SrS:Eu, Sm and CaS:Eu, Sm phosphors are presented. A type of novel OSL dosimeter is described. The dosimeter takes advantage of the characteristics of charge trapping materials SrS:Eu, Sm and CaS:Eu, Sm that exhibit optically stimulated luminescence (OSL). The measuring range of the dosimeter is from 0.01 to 1000 Gy. The OSL dosimeters provide capability for remote monitoring radiation locations which are difficult to access and hazardous. This equipment is relatively simple, small in size and has low power consumption. The device is suitable for space radiation dose exploration. In addition, it also can be used in IC and other radiation occasions and has good prospects.

  18. [3+3] Cyclocondensation of Disubstituted Biphenyl Dialdehydes: Access to Inherently Luminescent and Optically Active Hexa-substituted C3-Symmetric and Asymmetric Trianglimine Macrocycles.

    Science.gov (United States)

    Wang, Zhenzhen; Nour, Hany F; Roch, Loïc M; Guo, Minjie; Li, Wenjiao; Baldridge, Kim K; Sue, Andrew C H; Olson, Mark A

    2017-03-03

    A general synthetic route to inherently luminescent and optically active 6-fold substituted C3-symmetric and asymmetric biphenyl-based trianglimines has been developed. The synthesis of these hexa-substituted triangular macrocycles takes advantage of a convenient method for the synthesis of symmetrically and asymmetrically difunctionalized biphenyl dialdehydes through a convergent two-step aromatic nucleophilic substitution-one-pot Suzuki-coupling reaction protocol. A modular [3+3] diamine-dialdehyde cyclocondensation reaction between both the symmetrically and asymmetrically difunctionalized-4,4'-biphenyldialdehydes with enantiomerically pure (1R,2R)-1,2-diaminocyclohexane was employed to construct the hexa-substituted triangular macrocycles. B97-D/6-311G(2d,p) density functional theory determined structures and X-ray crystallographic analysis reveal that the six substituents appended to the biphenyl legs of the trianglimine macrocycles adopt an alternating conformation not unlike the 1,3,5-alternate conformation observed for calix[6]arenes. Reduction of the imine bonds using NaBH4 afforded the corresponding 6-fold substituted trianglamine without the need to alkylate the amine nitrogen atoms which could hinder their later use as metal coordination sites and without having to introduce asymmetric carbons.

  19. Energy absorption buildup factors, exposure buildup factors and Kerma for optically stimulated luminescence materials and their tissue equivalence for radiation dosimetry

    Science.gov (United States)

    Singh, Vishwanath P.; Badiger, N. M.

    2014-11-01

    Optically stimulated luminescence (OSL) materials are sensitive dosimetric materials used for precise and accurate dose measurement for low-energy ionizing radiation. Low dose measurement capability with improved sensitivity makes these dosimeters very useful for diagnostic imaging, personnel monitoring and environmental radiation dosimetry. Gamma ray energy absorption buildup factors and exposure build factors were computed for OSL materials using the five-parameter Geometric Progression (G-P) fitting method in the energy range 0.015-15 MeV for penetration depths up to 40 mean free path. The computed energy absorption buildup factor and exposure buildup factor values were studied as a function of penetration depth and incident photon energy. Effective atomic numbers and Kerma relative to air of the selected OSL materials and tissue equivalence were computed and compared with that of water, PMMA and ICRU standard tissues. The buildup factors and kerma relative to air were found dependent upon effective atomic numbers. Buildup factors determined in the present work should be useful in radiation dosimetry, medical diagnostics and therapy, space dosimetry, accident dosimetry and personnel monitoring.

  20. Stable, Free-space Optical Trapping and Manipulation of Sub-micron Particles in an Integrated Microfluidic Chip

    Science.gov (United States)

    Kim, Jisu; Shin, Jung H.

    2016-01-01

    We demonstrate stable, free-space optical trapping and manipulation in an integrated microfluidic chip using counter-propagating beams. An inverted ridge-type waveguide made of SU8 is cut across by an open trench. The design of the waveguide provides low propagation losses and small divergence of the trapping beam upon emergence from the facet, and the trench designed to be deeper and wider than the optical mode enables full utilization of the optical power with an automatic alignment for counter-propagating beams in a trap volume away from all surfaces. After integration with polydimethylsiloxane (PDMS) microfluidic channel for particle delivery, 0.65 μm and 1 μm diameter polystyrene beads were trapped in free space in the trench, and manipulated to an arbitrary position between the waveguides with a resolution of < 100 nm. Comparison with numerical simulations confirm stable trapping of sub-micron particles, with a 10 kBT threshold power of less than 1 mW and a stiffness that can be 1 order of magnitude larger than that of comparable fiber-based trapping methods. PMID:27653191

  1. Luminescence imaging using radionuclides: a potential application in molecular imaging

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jeong Chan [Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Il An, Gwang [Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Park, Se-Il [Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Oh, Jungmin [Korea Basic Science Institute Chuncheon Center, Gangwon-do 200-701 (Korea, Republic of); Kim, Hong Joo [Department of Physics and Energy Science, Kyungpook National University, Daegu 702-710 (Korea, Republic of); Su Ha, Yeong; Wang, Eun Kyung [Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Min Kim, Kyeong; Kim, Jung Young [Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Lee, Jaetae [Department of Nuclear Medicine, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Welch, Michael J. [Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110 (United States); Yoo, Jeongsoo, E-mail: yooj@knu.ac.k [Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of)

    2011-04-15

    Introduction: Nuclear and optical imaging are complementary in many aspects and there would be many advantages when optical imaging probes are prepared using radionuclides rather than classic fluorophores, and when nuclear and optical dual images are obtained using single imaging probe. Methods: The luminescence intensities of various radionuclides having different decay modes have been assayed using luminescence imaging and in vitro luminometer. Radioiodinated Herceptin was injected into a tumor-bearing mouse, and luminescence and microPET images were obtained. The plant dipped in [{sup 32}P]phosphate solution was scanned in luminescence mode. Radio-TLC plate was also imaged in the same imaging mode. Results: Radionuclides emitting high energy {beta}{sup +}/{beta}{sup -} particles showed higher luminescence signals. NIH3T6.7 tumors were detected in both optical and nuclear imaging. The uptake of [{sup 32}P]phosphate in plant was easily followed by luminescence imaging. Radio-TLC plate was visualized and radiochemical purity was quantified using luminescence imaging. Conclusion: Many radionuclides with high energetic {beta}{sup +} or {beta}{sup -} particles during decay were found to be imaged in luminescence mode due mainly to Cerenkov radiation. 'Cerenkov imaging' provides a new optical imaging platform and an invaluable bridge between optical and nuclear imaging. New optical imaging probes could be easily prepared using well-established radioiodination methods. Cerenkov imaging will have more applications in the research field of plant science and autoradiography.

  2. Up-conversion luminescence and optical temperature sensing behaviour of Yb3+/Er3+ codoped CaWO4 material

    Science.gov (United States)

    Cheng, Xuerui; Yang, Kun; Wang, Jiankun; Yang, Linfu; Cheng, Xiaoshuai

    2016-08-01

    Present article report on structural and optical properties of Er3+/Yb3+ codoped CaWO4 phosphors. Structural properties are explored using XRD and Raman technologies. The upconversion emission has been investigated with 980 nm excitation. The upconversion emission intensity is dependent on the concentrations of Yb3+ ions and reaches a maximum at 7%. Logarithmic plots of power dependencies reveal that the green and red emissions originate from a two-photon upconversion process. Based on the photon energy and the emission spectra, the possible upconversion processes and emission mechanisms are discussed. Finally, the optical temperature sensing properties has been performed using the fluorescence intensity ratio technique based on green upconversion emissions. Its temperature sensitivity is found to be above 0.0025 K-1 in the whole temperature range of 300-540 K, revealing this phosphor to be a promising optical temperature sensing material.

  3. Stable inverted small molecular organic solar cells using a p-doped optical spacer.

    Science.gov (United States)

    Lee, Sang-Hoon; Seo, Ji-Won; Lee, Jung-Yong

    2015-01-07

    We report inverted small molecular organic solar cells using a doped window layer as an optical spacer. The optical spacer was used to shift the optical field distribution inside the active layers, generating more charge carriers from sunlight. In this report, N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine (MeO-TPD) was doped with 2,2-(perfluoronaphthalene-2,6-diylidene)dimalononitrile (F6-TCNNQ), a p-type dopant material. P-doped MeO-TPD was adopted as an optical spacer because it has a large energy band gap, and its conductivity can be increased by several orders of magnitude through a doping process. As a result, a power conversion efficiency of 4.15% was achieved with the doped window layer of optimized thickness. Lastly, we present significantly improved stability of the inverted devices with the MeO-TPD layer.

  4. Rad-Tolerant, Thermally Stable, High-Speed Fiber-Optic Network for Harsh Environments

    Science.gov (United States)

    Leftwich, Matt; Hull, Tony; Leary, Michael; Leftwich, Marcus

    2013-01-01

    Future NASA destinations will be challenging to get to, have extreme environmental conditions, and may present difficulty in retrieving a spacecraft or its data. Space Photonics is developing a radiation-tolerant (rad-tolerant), high-speed, multi-channel fiber-optic transceiver, associated reconfigurable intelligent node communications architecture, and supporting hardware for intravehicular and ground-based optical networking applications. Data rates approaching 3.2 Gbps per channel will be achieved.

  5. Multifunctionality in bimetallic Ln(III)[W(V)(CN)8]3- (Ln = Gd, Nd) coordination helices: optical activity, luminescence, and magnetic coupling.

    Science.gov (United States)

    Chorazy, Szymon; Nakabayashi, Koji; Arczynski, Mirosław; Pełka, Robert; Ohkoshi, Shin-ichi; Sieklucka, Barbara

    2014-06-02

    Two chiral luminescent derivatives of pyridine bis(oxazoline) (Pybox), (SS/RR)-iPr-Pybox (2,6-bis[4-isopropyl-2-oxazolin-2-yl]pyridine) and (SRSR/RSRS)-Ind-Pybox (2,6-bis[8H-indeno[1,2-d]oxazolin-2-yl]pyridine), have been combined with lanthanide ions (Gd(3+), Nd(3+)) and octacyanotungstate(V) metalloligand to afford a remarkable series of eight bimetallic CN(-)-bridged coordination chains: {[Ln(III)(SS/RR-iPr-Pybox)(dmf)4]3[W(V)(CN)8]3}n ⋅dmf⋅4 H2O (Ln = Gd, 1-SS and 1-RR; Ln = Nd, 2-SS and 2-RR) and {[Ln(III)(SRSR/RSRS-Ind-Pybox)(dmf)4][W(V)(CN)8]}n⋅5 MeCN⋅4 MeOH (Ln = Gd, 3-SRSR and 3-RSRS; Ln = Nd, 4-SRSR and 4-RSRS). These materials display enantiopure structural helicity, which results in strong optical activity in the range 200-450 nm, as confirmed by natural circular dichroism (NCD) spectra and the corresponding UV/Vis absorption spectra. Under irradiation with UV light, the Gd(III)-W(V) chains show dominant ligand-based red phosphorescence, with λmax ≈660 nm for 1-(SS/RR) and 680 nm for 3-(SRSR/RSRS). The Nd(III)-W(V) chains, 2-(SS/RR) and 4-(SRSR/RSRS), exhibit near-infrared luminescence with sharp lines at 986, 1066, and 1340 nm derived from intra-f (4)F3/2 → (4)I9/2,11/2,13/2 transitions of the Nd(III) centers. This emission is realized through efficient ligand-to-metal energy transfer from the Pybox derivative to the lanthanide ion. Due to the presence of paramagnetic lanthanide(III) and [W(V)(CN)8](3-) moieties connected by cyanide bridges, 1-(SS/RR) and 3-(SRSR/RSRS) are ferrimagnetic spin chains originating from antiferromagnetic coupling between Gd(III) (SGd = 7/2) and W(V) (SW = 1/2) centers with J1-(SS) = -0.96(1) cm(-1), J1-(RR) =-0.95(1) cm(-1), J3-(SRSR) = -0.91(1) cm(-1), and J3-(RSRS) =-0.94(1) cm(-1). 2-(SS/RR) and 4-(SRSR/RSRS) display ferromagnetic coupling within their Nd(III)-NC-W(V) linkages.

  6. Fabrication, Study of Optical Properties and Structure of Most Stable (CdP2)n Nanoclusters

    OpenAIRE

    Yeshchenko, O. A.; Dmitruk, I. M.; Koryakov, S. V.; Galak, M. P.

    2005-01-01

    CdP2 nanoclusters were fabricated by incorporation into pores of zeolite Na-X and by laser ablation. Absorption and photoluminescence (PL) spectra of CdP2 nanoclusters in zeolite were measured at the temperatures of 4.2, 77 and 293 K. Both absorption and PL spectra consist of two bands blue shifted with respect to bulk crystal. We performed the calculations aimed to find the most stable clusters in the size region up to size of the zeolite Na-X supercage. The most stable clusters are (CdP2)6 ...

  7. An Ultra-Stable Referenced Interrogation System in the Deep Ultraviolet for a Mercury Optical Lattice Clock

    CERN Document Server

    Dawkins, S T; Petersen, M; Millo, J; Magalhães, D V; Mandache, C; Coq, Y Le; Bize, S

    2010-01-01

    We have developed an ultra-stable source in the deep ultraviolet, suitable to fulfill the interrogation requirements of a future fully-operational lattice clock based on neutral mercury. At the core of the system is a Fabry-P\\'erot cavity which is highly impervious to temperature and vibrational perturbations. The mirror substrate is made of fused silica in order to exploit the comparatively low thermal noise limits associated with this material. By stabilizing the frequency of a 1062.6 nm Yb-doped fiber laser to the cavity, and including an additional link to LNE-SYRTE's fountain primary frequency standards via an optical frequency comb, we produce a signal which is both stable at the 1E-15 level in fractional terms and referenced to primary frequency standards. The signal is subsequently amplified and frequency-doubled twice to produce several milliwatts of interrogation signal at 265.6 nm in the deep ultraviolet.

  8. Slip rate determination along the Southern Dead Sea fault: optically stimulated luminescence, 10Be cosmogenic radionuclide, and 14C ages brought face to face

    Science.gov (United States)

    Le Beon, Maryline; Jaiswal, Manoj; Kunz, Alexander; Al-Qaryouti, Mahmoud; Burr, George; Klinger, Yann; Moumani, Khaled; Chen, Yue-Gau; Abdelghafoor, Mohammed; Suppe, John

    2014-05-01

    Active tectonics studies are often limited by difficulties in accurately and precisely dating Late Quaternary alluvial deposits that commonly lack organic matter or date beyond the 14C dating limit. This is illustrated at a site called Fidan, in arid southern Jordan, where a series of alluvial fans are laterally offset by the southern Dead Sea fault. Geodetic, geomorphic and geologic studies converge to a fault slip rate of 5 ± 2 mm/a. Yet, Late Pleistocene slip rate at Fidan cover a wide range due to the dispersion of 10Be cosmogenic radionuclide (CRN) ages. The maximum slip rate since ~100 ka is up to a value of 11 mm/a, possibly suggesting significant variations in fault activity with time. In order to reduce the uncertainty on the Late Pleistocene slip rate and draw further conclusions regarding the fault seismic behavior, we implement complementary dating using optically stimulated luminescence (OSL) techniques on both quartz and K-feldspar minerals and using 14C when possible. OSL measurements include a newly developed technique called post-infra-red infra-red stimulated luminescence at 290°C (pIR290). We extensively sampled surface levels F2 and F4, digging ~50-cm deep pits into the geomorphic surfaces. Annual dose rates were determined in the laboratory from both geochemical analysis of the sediment and gamma-ray spectrometry. Due to sediment heterogeneity, we consider gamma-ray spectrometry as more reliable because it is based on a larger volume of sediment. Quartz OSL ages and preliminary pIR290 results on K-feldspars give consistent Early Holocene ages of 9-14 ka for F2, also in agreement with a 14C age of 13 ka from a landsnail shell. 10Be CRN exposure ages on F2 were significantly older, with 37 ± 4 ka, probably due to inheritance. On F4, 10Be CRN exposure ages showed a scattered distribution, from ~50 ka to ~120 ka, with most samples comprised in the mean interval of 87 ± 26 ka. Quartz OSL ages from 5 locations on F4 are comprised between 32 ± 3

  9. New Opportunities for Lanthanide Luminescence

    Institute of Scientific and Technical Information of China (English)

    Jean-Claude G. Bünzli; Steve Comby; Anne-Sophie Chauvin; Caroline D. B. Vandevyver

    2007-01-01

    Trivalent lanthanide ions display fascinating optical properties. The discovery of the corresponding elements and their first industrial uses were intimately linked to their optical properties. This relationship has been kept alive until today when many high-technology applications of lanthanide-containing materials such as energy-saving lighting devices, displays, optical fibers and amplifiers, lasers, responsive luminescent stains for biomedical analyses and in cellulo sensing and imaging, heavily rely on the brilliant and pure-color emission of lanthanide ions. In this review we first outlined the basics of lanthanide luminescence with emphasis on f-f transitions, the sensitization mechanisms, and the assessment of the luminescence efficiency of lanthanide-containing emissive molecular edifices. Emphasis was then put on two fast developing aspects of lanthanide luminescence: materials for telecommunications and light emitting diodes, and biomedical imaging and sensing. Recent advances in NIR-emitting materials for plastic amplifiers and waveguides were described, together with the main solutions brought by researchers to minimize non-radiative deactivation of excited states. The demonstration in 1999 that erbium tris(8-hydroxyquinolinate) displayed a bright green emission suitable for organic light emitting diodes (OLEDs) was followed by realizing that in OLEDs, 25% of the excitation energy leads to singlet states and 75% to triplet states. Since lanthanide ions are good triplet quenchers, they now also play a key role in the development of these lighting devices. Luminescence analyses of biological molecules are among the most sensitive analytical techniques known. The long lifetime of the lanthanide excited states allows time-resolved spectroscopy to be used, suppressing the sample autofluorescence and reaching very low detection limits. Not only visible lanthanide sensors are now ubiquitously provided in medical diagnosis and in cell imaging, but the

  10. Optical recording of stable holographic grating in a low Tg statistical copolymer covalently functionalized with an azo-dye

    Science.gov (United States)

    Cambiasso, Javier; Garate, Hernan; D'Accorso, Norma; Ledesma, Silvia; Goyanes, Silvia

    2015-11-01

    A novel photoaddressable copolymer with low glass transition temperature was synthesised and its optical properties were studied. The photoresponsive material was obtained from chemical modification of a poly(styrene-co-acrylic acid) copolymer. A holographic polarization grating was recorded in the material and was monitored by measuring its diffraction efficiency. It is shown that the holographic grating stored in the material is highly stable in time, despite the fact that the polymer glass transition temperature is near room temperature. This stability is a consequence of electrostatic interactions between the azo-groups and the carboxylic substituent group of the main polymer chain.

  11. On the Highly Stable Performance of Loss-Free Optical Burst Switching Networks

    Directory of Open Access Journals (Sweden)

    Milos Kozak

    2016-01-01

    Full Text Available Increase of bandwidth demand in data networks, driven by the continuous growth of the Internet and the increase of bandwidth greedy applications, raise the issue of how to support all the bandwidth requirements in the near future. Three optical switching paradigms have been defined and are being investigated: Optical Circuit Switching (OCS; Optical Packet Switching (OPS; and Optical Burst Switching (OBS. Among these paradigms, OBS is seen as the most appropriate solution today. However, OBS suffers from high burst loss as a result of contention in the bufferless mode of operation. This issue was investigated by Coutelen et al., 2009 who proposed the loss-free CAROBS framework whereby signal convertors of the optical signal to the electrical domain ensure electrical buffering. Convertors increase the network price which must be minimized to reduce the installation and operating costs of the CAROBS framework. An analysis capturing convertor requirements, with respect to the number of merging flows and CAROBS node offered load, was carried out. We demonstrated the convertor location significance, which led to an additional investigation of the shared wavelength convertors scenario. Shared wavelength convertors significantly decrease the number of required convertors and show great promise for CAROBS. Based on this study we can design a CAROBS network to contain a combination of simple and complex nodes that include none or some convertors respectively, a vital feature of network throughput efficiency and cost.

  12. Optical absorption, luminescence, and energy transfer processes studies for Dy3+/Tb3+-codoped borate glasses for solid-state lighting applications

    Science.gov (United States)

    Lakshminarayana, G.; Kaky, Kawa M.; Baki, S. O.; Lira, A.; Caldiño, U.; Kityk, I. V.; Mahdi, M. A.

    2017-10-01

    By using melt quenching technique, good optical quality singly doped Dy3+ or Tb3+ and Dy3+/Tb3+-codoped borate glasses were synthesized and studied by optical absorption, excitation, emission and decay lifetimes curve analysis. Following the absorption spectrum, the evaluated Judd-Ofelt (J-O) intensity parameters (Ωλ (λ = 2, 4 and 6)) were used to calculate the transition probability (AR), the branching ratio (βR), and the radiative lifetime (τR) for different luminescent transitions such as 4I15/2 → 6H15/2, 4F9/2 → 6H15/2, 4F9/2 → 6H13/2, 4F9/2 → 6H11/2 and 4F9/2 → 6H9/2,6F11/2 for the 0.5 mol % singly Dy3+-doped glass. The βR calculated (65%) indicates that for lasing applications, 4F9/2 → 6H13/2 emission transition is highly suitable. For all the Dy3+/Tb3+-codoped glasses, Tb3+: 5D3→7F6 emission decay lifetime curves are found to be non-exponential in nature for different concentrations of Dy3+ codoping. Using the Inokuti-Hirayama model, these nonexponential decay curves were analyzed to identify the nature of the energy transfer (ET) processes and here the electric dipole-dipole interaction is dominant for the ET. Based on the excitation and emission spectra and decay lifetimes curve analysis, the cross relaxation and ET processes between Dy3+ and Tb3+ were confirmed. For the 0.5 mol % Tb3+ and 2.0 mol % Dy3+-codoped glass, the evaluated Tb3+→Dy3+ ET efficiency (η) is found to be 45% under 369 nm excitation. Further, for Tb3+/Dy3+ -codoped glasses, an enhancement of Tb3+ green emission is observed up to 1.5 mol % Dy3+ codoping, and this is due to the non-radiative resonant ET from Dy3+ to Tb3+ upon 395 nm excitation. For singly 0.5 mol % Dy3+ or 0.5 mol % Tb3+-doped glass, the calculated color coordinates (x,y) and correlated color temperatures (CCT) represent the neutral white or warm white light regions, whereas Dy3+/Tb3+-codoped glasses (x,y) and CCT values fall in the yellowish green region with respect to the different Dy3

  13. Self assembly of microparticles in stable ring structures in an optical trap

    CERN Document Server

    Haldar, Arijit; Roy, Basudev; Gupta, S Dutta; Banerjee, Ayan

    2011-01-01

    Micro-particle self assembly under the influence of optical forces produced by higher order optical beams or by projection of a hologram into the trapping volume is well known. In this paper, we report the spontaneous formation of a ring of identical microspheres (each with diameter 1.1 um in conventional single beam optical tweezers having standing wave geometry with the sample chamber consisting of a cover slip and glass slide, and a usual TEM00 Gaussian beam. The effects of different experimental parameters on the ring formation are studied extensively. The experimental observations are backed by theoretical simulations based on a plane wave decomposition of the forward and backward propagating Gaussian beams. The ring patterns are shown to be caused due to geomterical aberrations produced by focusing the Gaussian beam using a high numerical aperture microscope objective into stratified media. It is found that the thickness of the stratified media and the standing wave geometry itself play a critical role ...

  14. Two-photon luminescence contrast by tip-sample coupling in femtosecond near-field optical microscopy

    Science.gov (United States)

    Horneber, Anke; Wackenhut, Frank; Braun, Kai; Wang, Xiao; Wang, Jiyong; Zhang, Dai; Meixner, Alfred J.

    2017-01-01

    We investigate the role of tip-sample interaction in nonlinear optical scanning near-field microscopy. The experiment was performed by tightly focusing femtosecond laser pulses onto a sharp gold tip that was positioned in close proximity to the surface of a sample with gold nanostructures on a Si-substrate by shear force feedback. The nonlinear optical signal consists of two-photon photoluminescence and second harmonic signal from the gold tip and the gold nanostructures. These signals can be used to characterize different coupling parameters such as geometry, material and width of the tip-sample gap and enable to reveal the mechanism responsible for the image contrast. Under the excitation with 776-nm and 110-fs laser pulses nonlinear imaging is almost background free and yields super resolution showing features with dimensions significantly below the diffraction limit with a signal intensity following quadratic excitation power law.

  15. Thermal History Using Microparticle Trap Luminescence

    Science.gov (United States)

    2012-06-01

    34 2008 IEEE/ LEOS Optical MEMS and Nanophotonics Conference, Freiburg Germany, August 2008, pp. 64- 65. 3. J. R. Hazelton, E. G. Yukihara, M. W. Blair...A.J.J. , Prokic, M. and Brouwer , J.C., 2006. Optically and thermally stimulated luminescence characteristics of MgO:Tb3+. Radiat. Prot. Dosim. 119

  16. Luminescence and optical absorption studies of submicro-dimensional cerium ortho- and metaphosphates doped with Eu{sup 3+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Matraszek, A. [Department of Inorganic Chemistry, Faculty of Engineering and Economics, Wroclaw University of Economics, 118/120 Komandorska str., 53-345 Wroclaw (Poland); Macalik, L. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland); Szczygiel, I. [Department of Inorganic Chemistry, Faculty of Engineering and Economics, Wroclaw University of Economics, 118/120 Komandorska str., 53-345 Wroclaw (Poland); Godlewska, P. [Department of Bioorganic Chemistry, Faculty of Engineering and Economics, Wroclaw University of Economics, 118/120 Komandorska str., 53-345 Wroclaw (Poland); Solarz, P. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland); Hanuza, J. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland)], E-mail: j.hanuza@int.pan.wroc.pl

    2008-02-28

    Pechini method has been applied for synthesis of the phosphates in the submicro-state. Dimensions of the obtained grains by this method fall into the 100-1000 nm range. The following samples have been synthesised: stoichiometric orthophosphate Na{sub 3}Ce(PO{sub 4}){sub 2} and metaphosphate NaCe(PO{sub 3}){sub 4} both doped with 2 and 5% of Eu{sup 3+}. Optical absorption and emission studies have been performed to characterise the properties and structure of the compounds studied. The electronic characteristics of the Ce{sup 3+} and Eu{sup 3+} ions in these materials have been discussed.

  17. Energy transfer from a dye donor to enhance the luminescence of silicon quantum dots

    Science.gov (United States)

    Erogbogbo, Folarin; Chang, Ching-Wen; May, Jasmine; Prasad, Paras N.; Swihart, Mark T.

    2012-07-01

    Quantum dots are known for their superior optical properties; however, when transferred into aqueous media, their luminescent properties are frequently compromised. When encapsulated in micelles for bioimaging applications, luminescent silicon quantum dots can lose as much as 50% of their luminescence depending on the formulation used. Here, we create an energy transfer micelle platform that combines silicon quantum dots with an anthracene-based dye in the hydrophobic core of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG) micelles. These phospholipid micelles are water dispersible, stable, and surrounded by a PEGylated layer with modifiable functional groups. The spectroscopic properties of energy transfer between the anthracene donors and silicon quantum dot acceptors were analyzed based on the observed dependence of the steady-state emission spectrum on concentration ratio, excitation wavelength, pH, and temperature. The luminescence of silicon quantum dots from the core of a 150 nm micelle is enhanced by more than 80% when the anthracene dye is added. This work provides a simple yet readily applicable solution to the long-standing problem of luminescence enhancement of silicon quantum dots and can serve as a template for improving the quantum dot emission yield for biological applications where luminescence signal enhancements are desirable and for solar applications where energy transfer plays a critical role in device performance.Quantum dots are known for their superior optical properties; however, when transferred into aqueous media, their luminescent properties are frequently compromised. When encapsulated in micelles for bioimaging applications, luminescent silicon quantum dots can lose as much as 50% of their luminescence depending on the formulation used. Here, we create an energy transfer micelle platform that combines silicon quantum dots with an anthracene-based dye in the hydrophobic core of 1

  18. Phase-Stable Free-Space Optical Lattices for Trapped Ions.

    Science.gov (United States)

    Schmiegelow, C T; Kaufmann, H; Ruster, T; Schulz, J; Kaushal, V; Hettrich, M; Schmidt-Kaler, F; Poschinger, U G

    2016-01-22

    We demonstrate control of the absolute phase of an optical lattice with respect to a single trapped ion. The lattice is generated by off-resonant free-space laser beams, and we actively stabilize its phase by measuring its ac-Stark shift on a trapped ion. The ion is localized within the standing wave to better than 2% of its period. The locked lattice allows us to apply displacement operations via resonant optical forces with a controlled direction in phase space. Moreover, we observe the lattice-induced phase evolution of spin superposition states in order to analyze the relevant decoherence mechanisms. Finally, we employ lattice-induced phase shifts for inferring the variation of the ion position over the 157  μm range along the trap axis at accuracies of better than 6 nm.

  19. Phase-stable free-space optical lattices for trapped ions

    CERN Document Server

    Schmiegelow, Christian Tomas; Ruster, Thomas; Schulz, Jonas; Kaushal, Vidyut; Hettrich, Max; Schmidt-Kaler, Ferdinand; Poschinger, Ulrich G

    2016-01-01

    We demonstrate control of the absolute phase of an optical lattice with respect to a single trapped ion. The lattice is generated by off-resonant free-space laser beams, we actively stabilize its phase by measuring its ac-Stark shift on a trapped ion. The ion is localized within the standing wave to better than 2\\% of its period. The locked lattice allows us to apply displacement operations via resonant optical forces with a controlled direction in phase space. Moreover, we observe the lattice-induced phase evolution of spin superposition states in order to analyze the relevant decoherence mechanisms. Finally, we employ lattice-induced phase shifts for inferring the variation of the ion position over 157~$\\mu$m range along the trap axis at accuracies of better than 6~nm.

  20. Regiospecific formation and unusual optical properties of 2,5-bis(arylethynyl)rhodacyclopentadienes: a new class of luminescent organometallics.

    Science.gov (United States)

    Steffen, Andreas; Ward, Richard M; Tay, Meng Guan; Edkins, Robert M; Seeler, Fabian; van Leeuwen, Magda; Pålsson, Lars-Olof; Beeby, Andrew; Batsanov, Andrei S; Howard, Judith A K; Marder, Todd B

    2014-03-24

    A series of 2,5-bis(arylethynyl)rhodacyclopentadienes has been prepared by a rare example of regiospecific reductive coupling of 1,4-(p-R-phenyl)-1,3-butadiynes (R=H, Me, OMe, SMe, NMe2, CF3, CO2Me, CN, NO2, -C≡C-(p-C6H4-NHex2), -C≡C-(p-C6H4-CO2Oct)) at [RhX(PMe3)4] (1) (X=-C≡C-SiMe3 (a), -C≡C-(p-C6H4-NMe2) (b), -C≡C-C≡C-(p-C6H4-NPh2) (c) or -C≡C-{p-C6H4-C≡C-(p-C6H4 -N(C6H13)2)} (d) or Me (e)), giving the 2,5-bis(arylethynyl) isomer exclusively. The rhodacyclopentadienes bearing a methyl ligand in the equatorial plane (compound 1 e) have been converted into their chloro analogues by reaction with HCl etherate. The rhodacycles thus obtained are stable to air and moisture in the solid state and the acceptor-substituted compounds are even stable to air and moisture in solution. The photophysical properties of the rhodacyclopentadienes are highly unusual in that they exhibit, exclusively, fluorescence between 500-800 nm from the S1 state, with quantum yields of Φ=0.01-0.18 and short lifetimes (τ=0.45-8.20 ns). The triplet state formation (Φ(ISC) =0.57 for 2 a) is exceptionally slow, occurring on the nanosecond timescale. This is unexpected, because the Rh atom should normally facilitate intersystem crossing within femto- to picoseconds, leading to phosphorescence from the T1 state. This work therefore highlights that in some transition-metal complexes, the heavy atom can play a more subtle role in controlling the photophysical behavior than is commonly appreciated.

  1. Highly stable ultrabroadband mid-IR optical parametric chirped-pulse amplifier optimized for superfluorescence suppression.

    Science.gov (United States)

    Moses, J; Huang, S-W; Hong, K-H; Mücke, O D; Falcão-Filho, E L; Benedick, A; Ilday, F O; Dergachev, A; Bolger, J A; Eggleton, B J; Kärtner, F X

    2009-06-01

    We present a 9 GW peak power, three-cycle, 2.2 microm optical parametric chirped-pulse amplification source with 1.5% rms energy and 150 mrad carrier envelope phase fluctuations. These characteristics, in addition to excellent beam, wavefront, and pulse quality, make the source suitable for long-wavelength-driven high-harmonic generation. High stability is achieved by careful optimization of superfluorescence suppression, enabling energy scaling.

  2. Optical enhanced luminescent measurements and sequential reagent mixing on a centrifugal microfluidic device for multi-analyte point-of-care applications

    Science.gov (United States)

    Bartholomeusz, Daniel A.; Davies, Rupert H.; Andrade, Joseph D.

    2006-02-01

    A centrifugal-based microfluidic device1 was built with lyophilized bioluminescent reagents for measuring multiple metabolites from a sample of less than 15 μL. Microfluidic channels, reaction wells, and valves were cut in adhesive vinyl film using a knife plotter with features down to 30 μm and transferred to metalized polycarbonate compact disks (CDs). The fabrication method was simple enough to test over 100 prototypes within a few months. It also allowed enzymes to be packaged in microchannels without exposure to heat or chemicals. The valves were rendered hydrophobic using liquid phase deposition. Microchannels were patterned using soft lithography to make them hydrophilic. Reagents and calibration standards were deposited and lyophilized in different wells before being covered with another adhesive film. Sample delivery was controlled by a modified CD ROM. The CD was capable of distributing 200 nL sample aliquots to 36 channels, each with a different set of reagents that mixed with the sample before initiating the luminescent reactions. Reflection of light from the metalized layer and lens configuration allowed for 20% of the available light to be collected from each channel. ATP was detected down to 0.1 μM. Creatinine, glucose, and galactose were also measured in micro and milliMolar ranges. Other optical-based analytical assays can easily be incorporated into the device design. The minimal sample size needed and expandability of the device make it easier to simultaneously measure a variety of clinically relevant analytes in point-of-care settings.

  3. Investigation of neutron converters for production of optically stimulated luminescence (OSL) neutron dosimeters using Al{sub 2}O{sub 3}:C

    Energy Technology Data Exchange (ETDEWEB)

    Mittani, J.C.R. [Department of Physics, Oklahoma State University, Stillwater, OK 74078-3072 (United States); Silva, A.A.R. da [Department of Physics, Oklahoma State University, Stillwater, OK 74078-3072 (United States); Vanhavere, F. [SCK.CEN, Belgian Nuclear Research Centre, Boeretang 200, 2400 Mol (Belgium); Akselrod, M.S. [Landauer, Inc., Stillwater Crystal Growth Division, 723 1/2 Eastgate Rd., Stillwater, OK 74074 (United States); Yukihara, E.G. [Department of Physics, Oklahoma State University, Stillwater, OK 74078-3072 (United States)]. E-mail: eduardo.yukihara@okstate.edu

    2007-07-15

    This paper presents the optically stimulated luminescence (OSL) properties of neutron dosimeters in powder and in the form of pellets prepared with a mixture of Al{sub 2}O{sub 3}:C and neutron converters. The neutron converters investigated were high density polyethylene (HDPE), lithium fluoride (LiF), lithium fluoride 95% enriched with {sup 6}Li ({sup 6}LiF), lithium carbonate 95% enriched with {sup 6}Li ({sup 6}Li{sub 2}CO{sub 3}), boric acid enriched with 99% of {sup 10}B (H{sub 3}{sup 10}BO{sub 3}) and gadolinium oxide (Gd{sub 2}O{sub 3}). The proportion of Al{sub 2}O{sub 3}:C and neutron converter in the mixture was varied to optimize the total OSL signal and neutron sensitivity. The neutron sensitivity and dose-response were determined for the OSL dosimeters using a bare {sup 252}Cf source and compared to the response of Harshaw TLD-600 and TLD-700 dosimeters ({sup 6}LiF:Mg,Ti and {sup 7}LiF:Mg,Ti). The results demonstrate the possibility of developing an OSL dosimeter made of Al{sub 2}O{sub 3}:C powder and neutron converter with a neutron sensitivity (defined as the ratio between the {sup 60}Co equivalent gamma dose and the reference neutron absorbed dose) and neutron-gamma discrimination comparable to the TLD-600/TLD-700 combination. It was shown that the shape of the OSL decay curves varied with the type of the neutron converter, demonstrating the influence of the energy deposition mechanism and ionization density on the OSL process in Al{sub 2}O{sub 3}:C.

  4. Study of thermoluminescence (TL) and optically stimulated luminescence (OSL) from α-keratin protein found in human hairs and nails: potential use in radiation dosimetry.

    Science.gov (United States)

    Mishra, D R; Soni, A; Rawat, N S; Bokam, G

    2016-05-01

    The thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of human nails and hairs containing α-keratin proteins have been investigated. For the present studies, black hairs and finger nails were selectively collected from individuals with ages between 25 and 35 years. The collected hairs/nails were cut to a size of TL glow peaks in the temperature range from 70 to 210 ° C. Continuous wave (CW)-OSL measurements of hair samples at a wavelength of 470 nm showed the presence of two distinct OSL components with photoionization cross section (PIC) values of about 1.65 × 10(-18) cm(2) and about 3.48 × 10(-19) cm(2), while measurements of nail samples showed PIC values of about 6.98 × 10(-18) cm(2) and about 8.7 × 10(-19) cm(2), respectively. This difference in PIC values for hair and nail samples from the same individual is attributed to different arrangement of α-keratin protein concentrations in the samples. The OSL sensitivity was found to vary ± 5 times among nail and hair samples from different individuals, with significant fading (60% in 11 h) at room temperature. The remaining signal (after fading) can be useful for dose estimation when a highly sensitive OSL reader is used. In the absorbed dose range of 100 mGy-100 Gy, both the TL and OSL signals of hair and nail samples showed linear dose dependence. The results obtained in the present study suggest that OSL using hair and nail samples may provide a supplementary method of dose estimation in radiological and nuclear emergencies.

  5. Quaternary glacial history of the Kanas Valley, Chinese Altai, NW China, constrained by electron spin resonance and optically stimulated luminescence datings

    Science.gov (United States)

    Yang, Jianqiang; Chen, Yixin; Xu, Xiangke; Cui, Zhijiu; Xiong, Heigang

    2017-10-01

    The Chinese Altai is located on the northern edge of Central Asia. Rich geological records of Quaternary glaciations are preserved in this area. However, the glacial history in the Chinese Altai has hardly been investigated. This study aims to rebuild the regional glacial history in the Kanas Valley of the Chinese Altai. We present 14 electron spin resonance (ESR) ages and 3 optically stimulated luminescence (OSL) ages from glacial landforms. By integrating with ages from previous studies, five major glacial advances are identified during Marine Oxygen Isotope Stages (MIS) 6, 5, 4, 3 and 2, with ages of 167.0 ± 16.0-123.0 ± 18.0 ka, 97.0 ± 19.0-78.0 ± 7.0 ka, 76.0 ± 16.0-73.1 ± 6.6 ka, 52.1 ± 7.8-34.4 ± 4.2 ka, and 28.0 ± 3.3-16.1 ± 1.5 ka respectively. The glacial advance during MIS 5 is the local Last Glacial Maximum, and glaciers became successively more restricted from MIS 5 to MIS 2. In addition, the extensive MIS 3 glacial advance in the Chinese Altai contrasts with the absence of MIS 3 glacial advance in the Mongolia Altai. These glacial patterns reflect that precipitation brought by the westerlies might play a primary role on driving glacial advances during the Last Glacial in the Chinese Altai. This glacial chronology is in reasonable agreement with existing glacial chronologies from other parts of the Altai, Tian Shan and Pamir, indicating similar climate controls on the patterns of Quaternary glaciation across Central Asia Highlands.

  6. The age of three Middle Palaeolithic sites: Single-grain optically stimulated luminescence chronologies for Pech de l'Azé I, II and IV in France.

    Science.gov (United States)

    Jacobs, Zenobia; Jankowski, Nathan R; Dibble, Harold L; Goldberg, Paul; McPherron, Shannon J P; Sandgathe, Dennis; Soressi, Marie

    2016-06-01

    Optically stimulated luminescence (OSL) measurements were made on individual, sand-sized grains of quartz from Middle Palaeolithic deposits at three sites (Pech de l'Azé I, II and IV) located close to one another in the Dordogne region of southwest France. We were able to calculate OSL ages for 69 samples collected from these three sites. These ages reveal periods of occupation between about 180 and 50 thousand years ago. Our single-grain OSL chronologies largely support previous age estimates obtained by thermoluminescence dating of burnt flints at Pech IV, electron spin resonance dating of tooth enamel at Pech I, II and IV and radiocarbon dating of bone at Pech I and IV, but provide a more complete picture due to the ubiquitous presence of sand-sized quartz grains used in OSL dating. These complete chronologies for the three sites have allowed us to compare the single-grain ages for similar lithic assemblages among the three sites, to test the correlations among them previously proposed by Bordes in the 1970s, and to construct our own correlative chronological framework for the three sites. This shows that similar lithic assemblages occur at around the same time, and that where a lithic assemblage is unique to one or found at two of the Pech sites, there are no deposits of chronologically equivalent age at the other Pech site(s). We interpret this to mean that, at least for these Pech de l'Azé sites, the Mousterian variants show temporal ordering. Whether or not this conclusion applies to the wider region and beyond, the hypothesis that Mousterian industrial variation is temporally ordered cannot be refuted at this time.

  7. Energy dependence measurement of small-type optically stimulated luminescence (OSL) dosimeter by means of characteristic X-rays induced with general diagnostic X-ray equipment.

    Science.gov (United States)

    Takegami, Kazuki; Hayashi, Hiroaki; Okino, Hiroki; Kimoto, Natsumi; Maehata, Itsumi; Kanazawa, Yuki; Okazaki, Tohru; Hashizume, Takuya; Kobayashi, Ikuo

    2016-01-01

    For X-ray inspections by way of general X-ray equipment, it is important to measure an entrance-skin dose. Recently, a small optically stimulated luminescence (OSL) dosimeter was made commercially available by Landauer, Inc. The dosimeter does not interfere with the medical images; therefore, it is expected to be a convenient detector for measuring personal exposure doses. In an actual clinical situation, it is assumed that X-rays of different energies will be detected by a dosimeter. For evaluation of the exposure dose measured by a dosimeter, it is necessary to know the energy dependence of the dosimeter. Our aim in this study was to measure the energy dependence of the OSL dosimeter experimentally in the diagnostic X-ray region. Metal samples weighing several grams were irradiated and, in this way, characteristic X-rays having energies ranging from 8 to 85 keV were generated. Using these mono-energetic X-rays, the dosimeter was irradiated. Simultaneously, the fluence of the X-rays was determined with a CdTe detector. The energy-dependent efficiency of the dosimeter was derived from the measured value of the dosimeter and the fluence. Moreover, the energy-dependent efficiency was calculated by Monte-Carlo simulation. The efficiency obtained in the experiment was in good agreement with that of the simulation. In conclusion, our proposed method, in which characteristic X-rays are used, is valuable for measurement of the energy dependence of a small OSL dosimeter in the diagnostic X-ray region.

  8. Surface transport and stable trapping of particles and cells by an optical waveguide loop.

    Science.gov (United States)

    Hellesø, Olav Gaute; Løvhaugen, Pål; Subramanian, Ananth Z; Wilkinson, James S; Ahluwalia, Balpreet Singh

    2012-09-21

    Waveguide trapping has emerged as a useful technique for parallel and planar transport of particles and biological cells and can be integrated with lab-on-a-chip applications. However, particles trapped on waveguides are continuously propelled forward along the surface of the waveguide. This limits the practical usability of the waveguide trapping technique with other functions (e.g. analysis, imaging) that require particles to be stationary during diagnosis. In this paper, an optical waveguide loop with an intentional gap at the centre is proposed to hold propelled particles and cells. The waveguide acts as a conveyor belt to transport and deliver the particles/cells towards the gap. At the gap, the diverging light fields hold the particles at a fixed position. The proposed waveguide design is numerically studied and experimentally implemented. The optical forces on the particle at the gap are calculated using the finite element method. Experimentally, the method is used to transport and trap micro-particles and red blood cells at the gap with varying separations. The waveguides are only 180 nm thick and thus could be integrated with other functions on the chip, e.g. microfluidics or optical detection, to make an on-chip system for single cell analysis and to study the interaction between cells.

  9. Light fields with an axially expanded intensity distribution for stable three-dimensional optical trapping.

    Science.gov (United States)

    Zwick, Susanne; Schaub, Christian; Haist, Tobias; Osten, Wolfgang

    2010-09-13

    We introduce a new kind of light field to improve and simplify the trapping process of axially displaced particles. To this end we employ a light field with an axially expanded intensity distribution, which at the same time enables stable axial trapping. We present simulations of the axial intensity distribution of the novel trapping field and first experimental results, which demonstrate the improvement of the reliability of the axial trapping process. The method can be used to automate trapping of particles that are located outside of the focal plane of the microscope.

  10. Stable 811.53 nm diode laser pump source for optically pumped metastable Ar laser

    Science.gov (United States)

    Gao, Jun; Zuo, Duluo; Zhao, Jun; Li, Bin; Yu, Anlan; Wang, Xinbing

    2016-10-01

    A stable external cavity diode laser coupled with volume Bragg grating for metastable argon atoms pumping is presented. The measured maximum output power of the continuous wave is 6.5 W when the spectral width (FWHM) is less than 21 pm around 811.53 nm and the power efficiency is 68%. The tuning range of the emission wavelength is bigger than 270 pm. The calculated deviation in relative absorption efficiency caused by the fluctuations of wavelength and power is less than 4%.

  11. Optically pure, water-stable metallo-helical ‘flexicate’ assemblies with antibiotic activity

    Science.gov (United States)

    Howson, Suzanne E.; Bolhuis, Albert; Brabec, Viktor; Clarkson, Guy J.; Malina, Jaroslav; Rodger, Alison; Scott, Peter

    2012-01-01

    The helicates—chiral assemblies of two or more metal atoms linked by short or relatively rigid multidentate organic ligands—may be regarded as non-peptide mimetics of α-helices because they are of comparable size and have shown some relevant biological activity. Unfortunately, these beautiful helical compounds have remained difficult to use in the medicinal arena because they contain mixtures of isomers, cannot be optimized for specific purposes, are insoluble, or are too difficult to synthesize. Instead, we have now prepared thermodynamically stable single enantiomers of monometallic units connected by organic linkers. Our highly adaptable self-assembly approach enables the rapid preparation of ranges of water-stable, helicate-like compounds with high stereochemical purity. One such iron(II) ‘flexicate’ system exhibits specific interactions with DNA, promising antimicrobial activity against a Gram-positive bacterium (methicillin-resistant Staphylococcus aureus, MRSA252), but also, unusually, a Gram-negative bacterium (Escherichia coli, MC4100), as well as low toxicity towards a non-mammalian model organism (Caenorhabditis elegans).

  12. Optical and morphological characterization by atomic force microscopy of luminescent 2-styrylpyridine derivative compounds with Poly(N-vinylcarbazole) films

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Gutierrez, E., E-mail: cuper_enrique@msn.com [Centro de Quimica, Instituto de Ciencias, Universidad Autonoma de Puebla, Complejo de Ciencias, ICUAP, Edif. 103-F, 22 Sur y San Claudio, C.P. 72570 Puebla, Puebla (Mexico); Percino, M.J.; Chapela, V.M. [Centro de Quimica, Instituto de Ciencias, Universidad Autonoma de Puebla, Complejo de Ciencias, ICUAP, Edif. 103-F, 22 Sur y San Claudio, C.P. 72570 Puebla, Puebla (Mexico); Maldonado, J.L. [Centro de Investigaciones en Optica A.C. (CIO), Lomas del Bosque 115, Col. Lomas del Campestre, C.P. 37150, Leon Guanajuato (Mexico)

    2011-07-01

    The present work addresses the optical and morphological properties of organic films based on low molecular weight dyes styrylpyridine derivatives 2-styrylpyridine (A), 4-chlorophenyl-2-vinylpyridine (B) and 4-fluorophenyl-2-vinylpyridine (C), embedded in a polymeric matrix poly(N-vinylcarbazole) (PVK). The films were prepared by a spin-coating technique from solutions with dye:PVK ratios of 0.25:1, 0.5:1 and 1:1. Solvents were chloroform and toluene. The molar absorption coefficient ({epsilon}) spectra for a dye:PVK mixture in solution were a combination of the absorptions of both components separately, but for the deposited films, the shape of the spectrum showed that the poly(N-vinylcarbazole) absorption dominated. However, when the same films were dissolved again in CHCl{sub 3}, their spectra showed an absorption shape similar to that of the solution mixture before the deposition. Solution viscosity measurements were carried out with an Ubbelohde glass capillary viscometer to corroborate the results that showed a better mixture of the dye with the host in chloroform. The morphology of the prepared films was analyzed by atomic force microscopy and exhibited a solvent effect, with a pinhole-free, smooth surface when toluene was used and a wavy surface with chloroform. The ratio dye:matrix was the principal parameter for obtaining optical quality films; for 0.25:1 and 0.5:1 ratios, the films were of good quality, but for 1:1, the dye was expelled from the PVK and a crystallization was present over the surface of the films. Film thickness was also measured and films deposited from toluene solutions gave an average thickness of 54 nm while films from chloroform solutions had an average thickness greater than 160 nm that increased depending on chromophore concentration.

  13. SU-E-T-315: The Change of Optically Stimulated Luminescent Dosimeters (OSLDs) Sensitivity by Accumulated Dose and High Dose

    Energy Technology Data Exchange (ETDEWEB)

    Han, S; Jung, H; Kim, M; Ji, Y; Kim, K [University of Science and Technology, Daejeon (Korea, Republic of); Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Choi, S; Park, S; Yoo, H [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Yi, C [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2014-06-01

    Purpose: The objective of this study is to evaluate radiation sensitivity of optical stimulated luminance dosimeters (OSLDs) by accumulated dose and high dose. Methods: This study was carried out in Co-60 unit (Theratron 780, AECL, and Canada) and used InLight MicroStar reader (Landauer, Inc., Glenwood, IL) for reading. We annealed for 30 min using optical annealing system which contained fluorescent lamps (Osram lumilux, 24 W, 280 ∼780 nm). To evaluate change of OSLDs sensitivity by repeated irradiation, the dosimeters were repeatedly irradiated with 1 Gy. And whenever a repeated irradiation, we evaluated OSLDs sensitivity. To evaluate OSLDs sensitivity after accumulated dose with 5 Gy, We irradiated dose accumulatively (from 1 Gy to 5 Gy) without annealing. And OSLDs was also irradiated with 15, 20, 30 Gy to certify change of OSLDs sensitivity after high dose irradiation. After annealing them, they were irradiated with 1Gy, repeatedly. Results: The OSLDs sensitivity increased up to 3% during irradiating seven times and decreased continuously above 8 times. That dropped by about 0.35 Gy per an irradiation. Finally, after 30 times irradiation, OSLDs sensitivity decreased by about 7%. For accumulated dose from 1 Gy to 5 Gy, OSLDs sensitivity about 1 Gy increased until 4.4% after second times accumulated dose compared with before that. OSLDs sensitivity about 1 Gy decreased by 1.6% in five times irradiation. When OSLDs were irradiated ten times with 1Gy after irradiating high dose (10, 15, 20 Gy), OSLDs sensitivity decreased until 6%, 9%, 12% compared with it before high dose irradiation, respectively. Conclusion: This study certified OSLDs sensitivity by accumulated dose and high dose. When irradiated with 1Gy, repeatedly, OSLDs sensitivity decreased linearly and the reduction rate of OSLDs sensitivity after high dose irradiation had dependence on irradiated dose.

  14. Feldspar, Infrared Stimulated Luminescence

    DEFF Research Database (Denmark)

    Jain, Mayank

    2014-01-01

    This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars.......This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars....

  15. Thermally Stable Guest-Host Polyetherketone Poled Polymer for Electro-Optical Applications

    Institute of Scientific and Technical Information of China (English)

    潘奇伟; 房昌水; 秦志辉; 顾庆天; 吴祥雯; 史伟; 余金中

    2002-01-01

    The high glass transition temperature polymer polyetherketone doped with disperse red 13 (DR13/PEK-c) has been prepared by the spin-coating method. Through in situ second-harmonic generation, the corona poling temperature was optimized by measuring the temperature dependence of the in situ second-harmonic generation signal intensity under the poling electric field. The linear electro-optic coefficients of the poled polymer films have been determined at 632.8nm by using a simple interferometric technique. The polymer system was measured after 13000h, and found that it remained at 80% of its initial value.

  16. Development and characterization of remote radiation dosimetry systems using optically stimulated luminescence of alumina:carbon and potassium bromide:europium

    Science.gov (United States)

    Klein, David Matthew

    Scope and Method of Study. To develop and test the performance of two different dosimetry systems; one for in situ, high-sensitivity, inexpensive environmental monitoring, and another for near-real-time medical dosimetry. The systems are based on remote interrogation of the optically stimulated luminescence (OSL) from Al2O3:C and KBr:Eu single crystal dosimeters (exposed to environmental and medical radiation fields, respectively) via fiber optic cables. The environmental system was tested in lab conditions using various radioactive sources including 60Co, 90 Sr, 137Cs, and 226Ra, as well as with 232Th-enriched soil stimulant. The medical system was tested under various diagnostic x-ray systems, including fluoroscopy and computed tomography (CT) machines, as well as with high dose rate 192Ir brachytherapy sources and 232 MeV proton therapy beams under simulated treatment conditions. Findings and Conclusions. The environmental system was shown to achieve sensitivity high enough for measuring an OSL signal resulting from a dose of ˜1 muGy, which is equivalent to ˜12 hours of natural background radiation. This sensitivity allows for monitoring of the radiation characteristics of a natural environment more rapidly and/or less expensively than existing methods, such as soil sampling and in situ gamma spectroscopy. The KBr:Eu-based medical system results show that the near-real-time data acquisition during irradiation allows for rapid quality assurance (QA) measurements that benefits from high spatial resolution. These features are not present in most current standard dosimeters such as thermoluminescent detectors and pencil ionization chambers. The dosimeter does exhibit energy dependence, and a sensitization during high dose rate procedures. As a result, a model has been proposed that provides a description of the possible mechanisms that govern the transfer of electrons and holes within KBr:Eu during OSL measurement at room temperature. Correction factors for these

  17. Stable, continuous-wave, intracavity, optical parametric oscillator pumped by a semiconductor disk laser (VECSEL).

    Science.gov (United States)

    Stothard, D J M; Hopkins, J-M; Burns, D; Dunn, M H

    2009-06-22

    We report relaxation oscillation free, true continuous-wave operation of a singly-resonant, intracavity optical parametric oscillator (OPO) based upon periodically-poled, MgO-doped LiNbO3 and pumped internal to the cavity of a compact, optically-excited semiconductor disk laser (or VECSEL). The very short upper-laser-state lifetime of this laser gain medium, coupled with the enhancing effect of the high-finesse pump laser cavity in which the OPO is located, enables a low threshold, high efficiency intracavity device to be operated free of relaxation oscillations in continuous-wave mode. By optimizing for low-power operation, parametric threshold was achieved at a diode-laser power of only 1.4 W. At 8.5 W of diode-laser power, 205 mW of idler power was extracted, indicating a total down-converted power of 1.25 W, and hence a down-conversion efficiency of 83%.

  18. Ultra-stable optical frequency dissemination on a multi-access fibre network

    CERN Document Server

    Bercy, Anthony; Pottie, Paul-Eric; Amy-Klein, Anne

    2016-01-01

    We report the dissemination of an ultrastable optical frequency signal to two distant users simultaneously using a branching network. The ultrastable signal is extracted along a main fibre link; it is optically tracked with a narrow-linewidth laser diode, which light is injected in a secondary link. The propagation noise of both links is actively compensated. We implement this scheme with two links of 50-km fibre spools, the extraction being setup at the mid-point of the main link. We show that the extracted signal at the end of the secondary link exhibits fractional frequency instability of 1.4x10-15 at 1-s measurement time, almost equal to the 1.3x10-15 instability of the main link output end. The long-term instabilities are also very similar, at a level of 3-5x10-20 at 3x104-s integration time. We also show that the setting up of this extraction device, or a simpler one, at the main link input, can test the proper functioning of the noise rejection on this main link. This work is a significant step towards...

  19. Preparation, theory, and biological applications of highly luminescent cadmium selenide/zinc sulfide quantum dots in optical and electron microscopy

    Science.gov (United States)

    Bouwer, James Christopher

    This dissertation describes the preparation, theory, and applications of ZnS overcoated CdSe (core) quantum dots for applications as fluorescent probes in optical microscopy and as electron energy loss spectroscopy (EELS) probes in electron microscopy, with applications to the biological sciences. The dissertation begins with a brief overview of quantum dots and their history. Next, a brief overview of the necessary semiconductor theory is discussed including the origin of the band gap, the origin of holes, the concepts of phonons, and trap states. Then, the role of the confinement potential in the quantum dot fluorescent spectrum is discussed in the context of the 3-dimensional spherical well. Included in this discussion is the role of excitonic electron-hole bound states. To provide a complete document useful to anyone who wishes to continue work along these lines, included is a methods section which describes the complete process of synthesis of the CdSe cores, overcoating the cores with ZnS, size selection of nanocrystals, water solubilization, and protein conjugation. The methods used in live cell labeling are included as well. In the section that follows, a discussion of the mathematical methods of image correlation spectroscopy (ICS) for extracting dynamic constants such as flow rates and diffusion constants from time lapse optical image data is discussed in the context of quantum dot fluorescent probes. Dynamic constants were obtained using live NIH3T3 mouse fibroblast cells labeled with IgG-anti-EGF conjugated quantum dots. These same cells were then fixed, imbedded in resin, sectioned to 100nm thick sections and imaged under the electron microscope. The electron dense cadmium selinide provides the contrast necessary to perform direct imaging of EGF receptor sites. In order to improve the data and move toward multi-channel imaging in the electron microscope, EELS spectroscopy and elemental mapping of quantum dots was performed. The theory along with a

  20. Luminescent hyperbolic metasurfaces

    Science.gov (United States)

    Smalley, J. S. T.; Vallini, F.; Montoya, S. A.; Ferrari, L.; Shahin, S.; Riley, C. T.; Kanté, B.; Fullerton, E. E.; Liu, Z.; Fainman, Y.

    2017-01-01

    When engineered on scales much smaller than the operating wavelength, metal-semiconductor nanostructures exhibit properties unobtainable in nature. Namely, a uniaxial optical metamaterial described by a hyperbolic dispersion relation can simultaneously behave as a reflective metal and an absorptive or emissive semiconductor for electromagnetic waves with orthogonal linear polarization states. Using an unconventional multilayer architecture, we demonstrate luminescent hyperbolic metasurfaces, wherein distributed semiconducting quantum wells display extreme absorption and emission polarization anisotropy. Through normally incident micro-photoluminescence measurements, we observe absorption anisotropies greater than a factor of 10 and degree-of-linear polarization of emission >0.9. We observe the modification of emission spectra and, by incorporating wavelength-scale gratings, show a controlled reduction of polarization anisotropy. We verify hyperbolic dispersion with numerical simulations that model the metasurface as a composite nanoscale structure and according to the effective medium approximation. Finally, we experimentally demonstrate >350% emission intensity enhancement relative to the bare semiconducting quantum wells.

  1. Application of luminescence techniques in retrospective dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Jungner, H.

    1999-01-01

    Luminescence signals measured from minerals within bricks or ceramic samples can provide information about the absorbed radiation dose. This feature has for several years been used in dating archaeological and geological samples and recently luminescence techniques have been intensively used far...... retrospective assessment of accident doses received by the population after a nuclear accident. The development of new luminescence techniques after the Chernobyl accident has considerably improved the sensitivity and precision in the evaluation of accident doses. This paper reviews the development work......, especially on optically stimulated luminescence methods for retrospective assessment of accident doses carried out at Riso National Laboratory in collaboration with the University of Helsinki as part bf a joint European Union research project. We demonstrate that doses lower than 100 mGy can be measured from...

  2. Orbital surveys of solar stimulated luminescence

    Science.gov (United States)

    Hemphill, W. R.; Theisen, A. F.; Tyson, R. M.; Granata, J. S.

    The Fraunhofer line discriminator (FLD) is an electro-optical device for imaging natural and manmade materials which have been stimulated to luminesce by the sun. An airborne FLD has been used to detect geochemically stressed vegetation, drought-stressed agricultural crops, industrial and residential pollution effluents, marine oil seeps, phosphate rock, uranium-bearing sandstone, and bioluminescent ocean plankton. Three-dimensional perspective plots of excitation and emission spectra, measured with a laboratory spectrometer, graphically depict similarities and differences in luminescence properties between sample materials. The laboratory data also include luminescence intensities at six Fraunhofer lines in the visible and near-infrared regions of the electromagnetic spectrum. Both the airborne and laboratory data suggest the feasibility of delineating and monitoring at least some of these luminescing materials from orbital altitude, such as a test flight aboard the Space Shuttle using an improved third-generation FLD.

  3. Radiation induced luminescence processes in c-BN

    DEFF Research Database (Denmark)

    Trinkler, L.; Berzina, B.; Benabdesselam, M.

    2004-01-01

    Spectral properties of cubic boron nitride have been studied using methods of photoluminescence (PL), X-ray excited luminescence (XL), thermoluminescence (TL) and optically stimulated luminescence. It is found that emission of cubic boron nitride is presented by 4 subbands, their relative yield...

  4. Luminescent Processes Elucidated by Simple Experiments on ZnS.

    Science.gov (United States)

    Schwankner, R.; And Others

    1981-01-01

    Describes some impurity-related optical properties of semiconductors, with special emphasis on the luminescence of zinc sulfide (ZnS). Presents and interprets five experiments using a ZnS screen, ultraviolet lamp, transparent Dewar liquid nitrogen, and a helium/neon gas base. Includes application of luminescence measurements to archaeology. (SK)

  5. SU-E-T-585: Optically-Stimulated Luminescent Dosimeters for Monitoring Pacemaker Dose in Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Apicello, L [Hofstra University, Hempstead, NY (United States); Riegel, A; Jamshidi, A [North Shore LIJ Health System, Lake Success, NY (United States)

    2015-06-15

    Purpose: A sufficient amount of ionizing radiation can cause failure to components of pacemakers. Studies have shown that permanent damage can occur after a dose of 10 Gy and minor damage to functionality occurs at doses as low as 2 Gy. Optically stimulated thermoluminescent dosimeters (OSLDs) can be used as in vivo dosimeters to predict dose to be deposited throughout the treatment. The purpose of this work is to determine the effectiveness of using OSLDs for in vivo dosimetry of pacemaker dose. Methods: As part of a clinical in vivo dosimetry experience, OSLDs were placed at the site of the pacemaker by the therapist for one fraction of the radiation treatment. OSLD measurements were extrapolated to the total dose to be received by the pacemaker during treatment. A total of 79 measurements were collected from November 2011 to December 2013 on six linacs. Sixty-six (66) patients treated in various anatomical sites had the dose of their pacemakers monitored. Results: Of the 79 measurements recorded, 76 measurements (96 %) were below 2 Gy. The mean and standard deviation were 50.12 ± 76.41 cGy. Of the 3 measurements that exceeded 2 Gy, 2 measurements matched the dose predicted in the treatment plan and 1 was repeated after an unexpectedly high Result. The repeated measurement yielded a total dose less than 2 Gy. Conclusion: This analysis suggests OSLDs may be used for in vivo monitoring of pacemaker dose. Further research should be performed to assess the effect of increased backscatter from the pacemaker device.

  6. Late Quaternary floods and droughts in the Nile valley, Sudan: new evidence from optically stimulated luminescence and AMS radiocarbon dating

    Science.gov (United States)

    Williams, M. A. J.; Williams, F. M.; Duller, G. A. T.; Munro, R. N.; El Tom, O. A. M.; Barrows, T. T.; Macklin, M.; Woodward, J.; Talbot, M. R.; Haberlah, D.; Fluin, J.

    2010-05-01

    Our results show that the late Pleistocene Nile in northern Sudan was shifting position and actively aggrading at 145 ± 20 kyr, 83 ± 24 kyr, 32 ± 8 kyr and 20.7 ± 0.2 kyr and indicate, for the first time, a phase of high-energy flow in the White Nile at 27.8 ± 3.2 kyr, with still high but somewhat reduced flow in that river at 13.3 kyr, 10 kyr and 4.8-4.0 kyr. Beach ridges associated with a 386 m strandline of the White Nile have OSL ages of 27.5 ± 2.7 kyr and 14.5 ± 1.6 kyr. The Holocene terraces and former channels of the main Nile have ages of 11 kyr, 6.5-5.0 kyr and 4.8-4.0 kyr, after which there was a general decline in flood discharge. The now arid main Nile valley in northern Sudan was significantly wetter during the early to middle Holocene, with a lake up to 450 km 2 in area, fed by an overflow channel from the early Holocene Nile between 9.5 kyr and 7.5 kyr. Previously stable late Pleistocene dunes were reactivated at intervals during the Holocene, with five samples from the White Nile valley indicating brief phases of Holocene dune activity at 9.9 ± 2.0 kyr, 9.0 ± 2.8 kyr, 6.6 ± 0.9 kyr, 4.8 ± 0.9 kyr and 2.9 ± 0.5 kyr, the earliest of which occurred within periods of generally wetter climate and higher Nile flow. The youngest freshwater shells on the Khor Abu Habl alluvial fan west of the White Nile correspond to a time of regionally wetter climate between 1.7 and 1.0 kyr. Our results suggest that millennial scale climatic instability may have been characteristic of Holocene climates in this region.

  7. The novel stable control scheme of the light source power in the closed-loop fiber optic gyroscope

    Energy Technology Data Exchange (ETDEWEB)

    Ji Zhongxiao [Graduate University of the Chinese Academy of Sciences, Beijing (China); Ma Caiwen, E-mail: jzx@opt.ac.cn [Xi' an Institute of Optics and Precision Mechanics of the Chinese Academy of Sciences, NO.17 Xinxi Road, New Industrial Park, Xi' an Hi-Tech Industrial Development Zone, Xi' an, Shaanxi (China)

    2011-02-01

    The light source power stability of the Fiber-Optic Gyroscope (FOG) affects directly the scale factor and bias stability of FOG. The typical control scheme of the light source power employs an additional photodetector to detect the output power of the light source. When the fiber loss of FOG varied due to the temperature change, the light power in the additional photodetector did not indicate this change, which decreased the control effect. The spike pulse overlapping on the gyro signal denotes potentially the change of the light power and fiber loss. In the novel scheme, the spike pulse is extracted from the gyro signal, and is transformed into the square wave by the differential circuit. According to the change of the square wave amplitude, FOG adjusts the bias current of the light source to keep the stable light power in the signal photodetector. It is a simple and low-cost scheme without an additional photodetector.

  8. Differently environment stable bio-silver nanoparticles: study on their optical enhancing and antibacterial properties.

    Directory of Open Access Journals (Sweden)

    Yekkuni L Balachandran

    Full Text Available Generally, limited research is extended in studying stability and applicational properties of silver nanoparticles (Ag NPs synthesized by adopting 'green chemistry' protocol. In this work, we report on the synthesis of stable Ag NPs using plant-derived materials such as leaf extract of Neem (Azadirachta indica and biopolymer pectin from apple peel. In addition, the applicational properties of Ag NPs such as surface-enhanced Raman scattering (SERS and antibacterial efficiencies were also investigated. As-synthesized nanoparticles (NPs were characterized using various instrumentation techniques. Both the plant materials (leaf extract and biopolymer favored the synthesis of well-defined NPs capped with biomaterials. The NPs were spherical in shape with an average particle size between 14-27 nm. These bio-NPs exhibited colloidal stability in most of the suspended solutions such as water, electrolyte solutions (NaCl; NaNO3, biological solution (bovine serum albumin, and in different pH solutions (pH 7; 9 for a reasonable time period of 120 hrs. Both the bio-NPs were observed to be SERS active through displaying intrinsic SERS signals of the Raman probe molecule (Nile blue A. The NPs were effective against the Escherichia coli bacterium when tested in nutrient broth and agar medium. Scanning and high-resolution transmission electron microscopy (SEM and HRTEM images confirmed cellular membrane damage of nanoparticle treated E. coli cells. These environmental friendly template Ag NPs can be used as an antimicrobial agent and also for SERS based analytical applications.

  9. An efficient stable optical polariser module for calibration of the S4UVN earth observation satellite

    Science.gov (United States)

    Rolt, Stephen; Calcines, Ariadna; Lomanowski, Bartosz; Bramall, David; Shaw, Benjamin

    2016-07-01

    We describe here an optical polariser module intended to deliver well characterised polarised light to an imaging spectrometer instrument. The instrument in question is the Sentinel-4/UVN Earth observation imaging spectrometer due to be deployed in 2019 in a geostationary orbit. The polariser module described here will be used in the ground based calibration campaign for this instrument. One critical task of the calibration campaign will be the highly accurate characterisation of the polarisation sensitivity of instrument. The polariser module provides a constant, uniform source of linearly polarised light whose direction can be adjusted without changing the output level or uniformity of the illumination. A critical requirement of the polariser module is that the illumination is uniform across the exit pupil. Unfortunately, a conventional Glan-Taylor arrangement cannot provide this uniformity due to the strong variation in transmission at a refractive surface for angles close to the critical angle. Therefore a modified prism arrangement is proposed and this is described in detail. Detailed tolerance modelling and straylight modelling is also reported here.

  10. Stable hole doping of graphene for low electrical resistance and high optical transparency

    Energy Technology Data Exchange (ETDEWEB)

    Tongay, S; Berke, K; Nasrollahi, Z; Tanner, D B; Hebard, A F [Department of Physics, University of Florida, Gainesville, FL 32611 (United States); Lemaitre, M; Appleton, B R, E-mail: tongay@phys.ufl.edu, E-mail: afh@phys.ufl.edu, E-mail: appleton@eng.ufl.edu [Department of Material Science and Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2011-10-21

    We report on the p doping of graphene with the polymer TFSA ((CF{sub 3}SO{sub 2}){sub 2}NH). Modification of graphene with TFSA decreases the graphene sheet resistance by 70%. Through such modification, we report sheet resistance values as low as 129 {Omega}, thus attaining values comparable to those of indium-tin oxide (ITO), while displaying superior environmental stability and preserving electrical properties over extended time scales. Electrical transport measurements reveal that, after doping, the carrier density of holes increases, consistent with the acceptor nature of TFSA, and the mobility decreases due to enhanced short-range scattering. The Drude formula predicts that competition between these two effects yields an overall increase in conductivity. We confirm changes in the carrier density and Fermi level of graphene through changes in the Raman G and 2D peak positions. Doped graphene samples display high transmittance in the visible and near-infrared spectrum, preserving graphene's optical properties without any significant reduction in transparency, and are therefore superior to ITO films in the near infrared. The presented results allow integration of doped graphene sheets into optoelectronics, solar cells, and thermoelectric solar cells as well as engineering of the electrical characteristics of various devices by tuning the Fermi level of graphene.

  11. Recent progress in biomedical applications of persistent luminescence nanoparticles.

    Science.gov (United States)

    Wang, Jie; Ma, Qinqin; Wang, Yingqian; Shen, Haijing; Yuan, Quan

    2017-05-18

    Persistent luminescence nanoparticles (PLNPs) are an emerging group of promising luminescent materials that can remain luminescent after the excitation ceases. In the past decade, PLNPs with intriguing optical properties have been developed and their applications in biomedicine have been widely studied. Due to the ultra-long decay time of persistent luminescence, autofluorescence interference in biosensing and bioimaging can be efficiently eliminated. Moreover, PLNPs can remain luminescent for hours, making them valuable in bio-tracing. Also, persistent luminescence imaging can guide cancer therapy with a high signal-to-noise ratio (SNR) and superior sensitivity. Briefly, PLNPs are demonstrated to be a newly-emerging class of functional materials with unprecedented advantages in biomedicine. In this review, we summarized recent advances in the preparation of PLNPs and the applications of PLNPs in biosensing, bioimaging and cancer therapy.

  12. Enhancing and quenching luminescence with gold nanoparticle films: the influence of substrate on the luminescent properties

    Science.gov (United States)

    José Guidelli, Eder; Ramos, Ana Paula; Baffa, Oswaldo

    2016-01-01

    Gold nanoparticle (AuNP) films were sputtered over glass and aluminum substrates to enhance optically stimulated luminescence (OSL), a luminescent technique employed for radiation detection, from x-ray irradiated NaCl nanocrystals. The AuNP films deposited over glass led to enhanced-OSL emission, whereas the AuNP films deposited on aluminum substrates quenched the OSL emission. The enhanced-OSL intensity is proportional to the optical density of the film's plasmon resonance band at the stimulation wavelength. For the case of the AuNP/aluminum films, the luminescence quenching diminishes, and OSL intensity partially recovers upon increasing the distance between the AuNPs and the aluminum substrates, and between the luminescent nanocrystals and the AuNP films. These results suggest that plasmonic interactions between the emitter nanocrystals, the localized surface plasmons (LSP) of the AuNPs, and the substrate are responsible for the OSL enhancement and quenching. In this sense, the substrate dictates whether LSP relaxation occurs by radiative or non-radiative transisitions, leading to enhanced or quenched OSL, respectively. Therefore, besides showing that AuNP films can enhance and/or tune the sensitivity of luminescent radiation detectors, and demonstrating OSL as a new technique to investigate mechanisms of plasmon-enhanced luminescence, these results bring insights on how substrates strongly modify the optical properties of AuNP films.

  13. Development and implementation of a remote audit tool for high dose rate (HDR) Ir-192 brachytherapy using optically stimulated luminescence dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Casey, Kevin E.; Kry, Stephen F.; Howell, Rebecca M.; Followill, David [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030 (United States); Alvarez, Paola; Lawyer, Ann [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

    2013-11-15

    Purpose: The aim of this work was to create a mailable phantom with measurement accuracy suitable for Radiological Physics Center (RPC) audits of high dose-rate (HDR) brachytherapy sources at institutions participating in National Cancer Institute-funded cooperative clinical trials. Optically stimulated luminescence dosimeters (OSLDs) were chosen as the dosimeter to be used with the phantom.Methods: The authors designed and built an 8 × 8 × 10 cm{sup 3} prototype phantom that had two slots capable of holding Al{sub 2}O{sub 3}:C OSLDs (nanoDots; Landauer, Glenwood, IL) and a single channel capable of accepting all {sup 192}Ir HDR brachytherapy sources in current clinical use in the United States. The authors irradiated the phantom with Nucletron and Varian {sup 192}Ir HDR sources in order to determine correction factors for linearity with dose and the combined effects of irradiation energy and phantom characteristics. The phantom was then sent to eight institutions which volunteered to perform trial remote audits.Results: The linearity correction factor was k{sub L}= (−9.43 × 10{sup −5}× dose) + 1.009, where dose is in cGy, which differed from that determined by the RPC for the same batch of dosimeters using {sup 60}Co irradiation. Separate block correction factors were determined for current versions of both Nucletron and Varian {sup 192}Ir HDR sources and these vendor-specific correction factors differed by almost 2.6%. For the Nucletron source, the correction factor was 1.026 [95% confidence interval (CI) = 1.023–1.028], and for the Varian source, it was 1.000 (95% CI = 0.995–1.005). Variations in lateral source positioning up to 0.8 mm and distal/proximal source positioning up to 10 mm had minimal effect on dose measurement accuracy. The overall dose measurement uncertainty of the system was estimated to be 2.4% and 2.5% for the Nucletron and Varian sources, respectively (95% CI). This uncertainty was sufficient to establish a ±5% acceptance

  14. Household and workplace chemicals as retrospective luminescence dosemeters

    DEFF Research Database (Denmark)

    Thomsen, Kristina Jørkov; Bøtter-Jensen, L.; Murray, A.S.

    2002-01-01

    , there are Other potential unheated crystalline materials found in the domestic and industrial environment which may also act as retrospective dosemeters, and may be considerably more sensitive. We have Surveyed the thermoluminescent and optically stimulated luminescent (OSL) characteristics of several...

  15. Ultrahigh phase-stable swept-source optical coherence tomography as a cardiac imaging platform (Conference Presentation)

    Science.gov (United States)

    Ling, Yuye; Hendon, Christine P.

    2016-02-01

    Functional extensions to optical coherence tomography (OCT) provide useful imaging contrasts that are complementary to conventional OCT. Our goal is to characterize tissue types within the myocardial due to remodeling and therapy. High-speed imaging is necessary to extract mechanical properties and dynamics of fiber orientation changes in a beating heart. Functional extensions of OCT such as polarization sensitive and optical coherence elastography (OCE) require high phase stability of the system, which is a drawback of current mechanically tuned swept source OCT systems. Here we present a high-speed functional imaging platform, which includes an ultrahigh-phase-stable swept source equipped with KTN deflector from NTT-AT. The swept source does not require mechanical movements during the wavelength sweeping; it is electrically tuned. The inter-sweep phase variance of the system was measured to be less than 300 ps at a path length difference of ~2 mm. The axial resolution of the system is 20 µm and the -10 dB fall-off depth is about 3.2 mm. The sample arm has an 8 mmx8 mm field of view with a lateral resolution of approximately 18 µm. The sample arm uses a two-axis MEMS mirror, which is programmable and capable of scanning arbitrary patterns at a sampling rate of 50 kHz. Preliminary imaging results showed differences in polarization properties and image penetration in ablated and normal myocardium. In the future, we will conduct dynamic stretching experiments with strips of human myocardial tissue to characterize mechanical properties using OCE. With high speed imaging of 200 kHz and an all-fiber design, we will work towards catheter-based functional imaging.

  16. NIR luminescent Er{sup 3+}/Yb{sup 3+} co-doped SiO{sub 2}-ZrO{sub 2} nanostructured planar and channel waveguides: Optical and structural properties

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Cesar dos Santos [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto/SP (Brazil); Ferrari, Jefferson Luis [Grupo de Pesquisa em Quimica de Materiais - (GPQM), Departamento de Ciencias Naturais, Universidade Federal de Sao Joao Del Rei, Campus Dom Bosco, Praca Dom Helvecio, 74, 36301-160, Sao Joao Del Rei, MG (Brazil); Oliveira, Drielly Cristina de [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto/SP (Brazil); Maia, Lauro June Queiroz [Grupo Fisica de Materiais, Instituto de Fisica, UFG, Campus Samambaia, Caixa Postal 131, 74001-970, Goiania/GO (Brazil); Gomes, Anderson Stevens Leonidas [Departamento de Fisica, Universidade Federal de Pernambuco, Cidade Universitaria, Recife/PE, 50670-901 (Brazil); Ribeiro, Sidney Jose Lima [Laboratorio de Materiais Fotonicos, Instituto de Quimica, UNESP, Caixa Postal 355, 14801-970, Araraquara/SP (Brazil); and others

    2012-09-14

    Optical and structural properties of planar and channel waveguides based on sol-gel Er{sup 3+} and Yb{sup 3+} co-doped SiO{sub 2}-ZrO{sub 2} are reported. Microstructured channels with high homogeneous surface profile were written onto the surface of multilayered densified films deposited on SiO{sub 2}/Si substrates by a femtosecond laser etching technique. The densification of the planar waveguides was evaluated from changes in the refractive index and thickness, with full densification being achieved at 900 Degree-Sign C after annealing from 23 up to 500 min, depending on the ZrO{sub 2} content. Crystal nucleation and growth took place together with densification, thereby producing transparent glass ceramic planar waveguides containing rare earth-doped ZrO{sub 2} nanocrystals dispersed in a silica-based glassy host. Low roughness and crack-free surface as well as high confinement coefficient were achieved for all the compositions. Enhanced NIR luminescence of the Er{sup 3+} ions was observed for the Yb{sup 3+}-codoped planar waveguides, denoting an efficient energy transfer from the Yb{sup 3+} to the Er{sup 3+} ion. Highlights: Black-Right-Pointing-Pointer Sol-gel high NIR luminescent nanostructured planar and channel waveguides. Black-Right-Pointing-Pointer Microstructured channels written by a femtosecond laser etching technique. Black-Right-Pointing-Pointer Transparent glass ceramic with rare earth-doped ZrO{sub 2} nanocrystals in a silica host. Black-Right-Pointing-Pointer Enhanced NIR luminescence, efficient energy transfer from the Yb{sup 3+} to the Er{sup 3+} ion. Black-Right-Pointing-Pointer New planar channel waveguides to be applied as EDWA in the C telecommunication band.

  17. Luminescence and the light emitting diode the basics and technology of leds and the luminescence properties of the materials

    CERN Document Server

    Williams, E W; Pamplin, BR

    2013-01-01

    Luminescence and the Light Emitting Diode: The Basics and Technology of LEDS and the Luminescence Properties of the Materials focuses on the basic physics and technology of light emitting diodes (LEDS) and pn junction lasers as well as their luminescence properties. Optical processes in semiconductors and the useful devices which can be made are discussed. Comprised of 10 chapters, this book begins with an introduction to the crystal structure and growth, as well as the optical and electrical properties of LED materials. The detailed fabrication of the LED is then considered, along with the lu

  18. Optical and X-ray emission from stable millisecond magnetars formed from the merger of binary neutron stars

    CERN Document Server

    Metzger, Brian D

    2013-01-01

    The coalescence of binary neutron stars (NSs) may in some cases produce a stable massive NS remnant rather than a black hole. Due to the substantial angular momentum from the binary, such a remnant is born rapidly rotating and likely acquires a strong magnetic field (a `millisecond magnetar'). Magnetic spin-down deposits a large fraction of the rotational energy from the magnetar behind the small quantity of mass ejected during the merger. This has the potential for creating a bright transient that could be useful for determining whether a NS or black hole was formed in the merger. We investigate the expected signature of such an event, including for the first time the important impact of electron/positron pairs injected by the millisecond magnetar into the surrounding nebula. These pairs cool via synchrotron and inverse Compton emission, producing a pair cascade and hard X-ray spectrum. A fraction of these X-rays are absorbed by the ejecta walls and re-emitted as thermal radiation, leading to an optical/UV t...

  19. Comparative dose evaluations between XVI and OBI cone beam CT systems using Gafchromic XRQA2 film and nanoDot optical stimulated luminescence dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Giaddui, Tawfik; Cui Yunfeng; Galvin, James; Yu Yan; Xiao Ying [Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States)

    2013-06-15

    Purpose: To investigate the effect of energy (kVp) and filters (no filter, half Bowtie, and full Bowtie) on the dose response curves of the Gafchromic XRQA2 film and nanoDot optical stimulated luminescence dosimeters (OSLDs) in CBCT dose fields. To measure surface and internal doses received during x-ray volume imager (XVI) (Version R4.5) and on board imager (OBI) (Version 1.5) CBCT imaging protocols using these two types of dosimeters. Methods: Gafchromic XRQA2 film and nanoDot OSLD dose response curves were generated at different kV imaging settings used by XVI (software version R4.5) and OBI (software version 1.5) CBCT systems. The settings for the XVI system were: 100 kVp/F0 (no filter), 120 kVp/F0, and 120 kVp/F1 (Bowtie filter), and for the OBI system were: 100 kVp/full fan, 125 kVp/full fan, and 125 kVp/half fan. XRQA2 film was calibrated in air to air kerma levels between 0 and 11 cGy and scanned using reflection scanning mode with the Epson Expression 10000 XL flat-bed document scanner. NanoDot OSLDs were calibrated on phantom to surface dose levels between 0 and 14 cGy and read using the inLight{sup TM} MicroStar reader. Both dosimeters were used to measure in field surface and internal doses in a male Alderson Rando Phantom. Results: Dose response curves of XRQA2 film and nanoDot OSLDs at different XVI and OBI CBCT settings were reported. For XVI system, the surface dose ranged between 0.02 cGy in head region during fast head and neck scan and 4.99 cGy in the chest region during symmetry scan. On the other hand, the internal dose ranged between 0.02 cGy in the head region during fast head and neck scan and 3.17 cGy in the chest region during chest M20 scan. The average (internal and external) dose ranged between 0.05 cGy in the head region during fast head and neck scan and 2.41 cGy in the chest region during chest M20 scan. For OBI system, the surface dose ranged between 0.19 cGy in head region during head scan and 4.55 cGy in the pelvis region during

  20. Cerenkov luminescence imaging of medical isotopes

    OpenAIRE

    Ruggiero, Alessandro; Holland, Jason P.; Lewis, Jason S.; Grimm, Jan

    2010-01-01

    The development of novel multimodality imaging agents and techniques represents the current frontier of research in the field of medical imaging science. However, the combination of nuclear tomography with optical techniques has yet to be established. Here, we report the use of the inherent optical emissions from the decay of radiopharmaceuticals for Cerenkov luminescence imaging (CLI) of tumors in vivo and correlate the results with those obtained from concordant immuno-PET studies.

  1. Infrared stimulated luminescence dating of an Eemian (MIS 5e) site in Denmark using K-feldspar

    DEFF Research Database (Denmark)

    Buylaert, Jan-Pieter; Huot, Sebastian; Murray, Andrew S.

    2011-01-01

    Infrared stimulated luminescence (IRSL) dating of K-feldspars may be an alternative to quartz optically stimulated luminescence (OSL) dating when the quartz OSL signal is too close to saturation or when the quartz luminescence characteristics are unsuitable. In this paper, Eemian (MIS 5e) coastal...

  2. Synthesis, luminescence and nonlinear optical properties of homoleptic tetracyanamidogermanates ARE[Ge(CN{sub 2}){sub 4}] (A = K, Cs, and RE = La, Ce, Pr, Nd, Sm, Eu, Gd)

    Energy Technology Data Exchange (ETDEWEB)

    Dolabdjian, Konstantin; Schedel, Christine; Meyer, Hans-Juergen [Abteilung fuer Festkoerperchemie und Theoretische Anorganische Chemie, Institut fuer Anorganische Chemie, Universitaet Tuebingen (Germany); Enseling, David; Juestel, Thomas [Fachbereich Chemieingenieurwesen, FH Muenster, Steinfurt (Germany)

    2017-04-04

    Two new series of tetracyanamidogermanates were prepared by solid-state reaction of appropriate amounts of REF{sub 3} (RE = rare earth), A{sub 2}[GeF{sub 6}] (A = alkaline), and Li{sub 2}(CN{sub 2}) in evacuated silica tubes. Powder X-ray diffraction patterns of crystalline samples of KRE[Ge(CN{sub 2}){sub 4}] and CsRE[Ge(CN{sub 2}){sub 4}] were indexed isotypically to KRE[Si(CN{sub 2}){sub 4}] and RbRE[Ge(CN{sub 2}){sub 4}], respectively. Luminescence properties of Ce{sup 3+}, Eu{sup 3+}, and Tb{sup 3+} doped compounds and non-linear optical properties (NLO) of KRE[Ge(CN{sub 2}){sub 4}] are reported. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Thermoluminescence and optically stimulated luminescence properties of the 0.5P{sub 2}O{sub 5}-xBaO-(0.5-x)Li{sub 2}O glass systems

    Energy Technology Data Exchange (ETDEWEB)

    Timar-Gabor, A., E-mail: alida.timar@ubbcluj.r [Faculty of Environmental Science, Babes-Bolyai University, Fantanele 30, 400294 Cluj Napoca (Romania); Ivascu, C. [Faculty of Physics, Babes-Bolyai University, Kogalniceanu 1, 400084 Cluj Napoca (Romania); Vasiliniuc, S. [Faculty of Environmental Science, Babes-Bolyai University, Fantanele 30, 400294 Cluj Napoca (Romania); Daraban, L.; Ardelean, I. [Faculty of Physics, Babes-Bolyai University, Kogalniceanu 1, 400084 Cluj Napoca (Romania); Cosma, C. [Faculty of Environmental Science, Babes-Bolyai University, Fantanele 30, 400294 Cluj Napoca (Romania); Cozar, O. [Faculty of Physics, Babes-Bolyai University, Kogalniceanu 1, 400084 Cluj Napoca (Romania)

    2011-05-15

    Thermoluminescence and optically stimulated luminescence properties of phosphate glasses doped with BaO and Li{sub 2}O at various concentrations were studied. Lithium-doped glasses show a broad TL peak in the 200-300 {sup o}C region with poor dosimetric characteristics. Barium-doped glasses feature at least two TL peaks, approximately at 200 and 400 {sup o}C, which were attributed to Ba{sup 2+} ions. They also produce a fast-decaying OSL signal correlated with the lower-temperature TL peak. Responses of both TL emissions to radiation doses up to 100 Gy are linear (R{sup 2}>0.99). Due to its encouraging characteristics such as acceptable batch homogeneity, good measurement reproducibility and weak signal fading, the P{sub 2}O{sub 5}-BaO glass can be considered as a candidate material for dosimetry in the high-dose range (>10 Gy).

  4. Photostimulated luminescence properties of Eu2+ -doped barium aluminate phosphor.

    Science.gov (United States)

    He, Quanlong; Qiu, Guangyu; Xu, Xuhui; Qiu, Jianbei; Yu, Xue

    2015-03-01

    An intense green photostimulated luminescence in BaAl2 O4 :Eu(2+) phosphor was prepared. The thermoluminescence results indicate that there are at least three types of traps (T1 , T2 , T3 ) with different trap depths in BaAl2 O4 :Eu(2+) phosphor according to the bands located at 327, 361 and 555 K, respectively, which are closely associated with the phosphor's long persistent luminescence and photostimulated luminescence properties. In addition, as a novel optical read-out form, a photostimulated persistent luminescence signal can be repeatedly obtained in BaAl2 O4 :Eu(2+) phosphor. This shows that re-trapping of the electron released from a deep trap plays an important role in photostimulated persistent luminescence.

  5. On the relationship between luminescence excitation spectra and feldspar mineralogy

    DEFF Research Database (Denmark)

    Poolton, N.R.J.; Bøtter-Jensen, L.; Johnsen, O.

    1996-01-01

    Feldspar minerals can be used as naturally occurring radiation dosemeters, with dose assessment commonly using luminescence techniques. Since many feldspars contain radioactive K-40, knowledge of the mineralogy of the luminescent samples being measured is of high importance. Most feldspars contain...... more than trace amounts of highly luminescent Fe3+ impurities, and this article examines the relationship between features of the luminescence excitation spectrum of this ion with sample mineralogy. It is demonstrated that there is a near linear correspondence between the plagioclase feldspar...... groups. The results are compared with properties of the excitation spectra dose-dependent optically stimulated luminescence (OSL) in order to compare the chemical environment of the OSL donor defect, and the isolated Fe3+ centres....

  6. Luminescence characteristics of dental ceramics for retrospective dosimetry: a preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Bailiff, I.K.; Correcher, V.; Delgado, A.; Goksu, Y.; Huebner, S

    2002-07-01

    Ceramic materials that are widely employed in dental prosthetics and repairs exhibit luminescent properties. Because of their use in the body, these materials are potentially of interest in situations where retrospective dosimetry for individuals is required but where monitoring was not planned. The luminescent properties of dental ceramics obtained in Germany, Spain and the UK were examined. Linear dose-response characteristics were obtained in the range <100 mGy to 10 Gy using thermoluminescence (TL), optically stimulated luminescence and infrared-stimulated luminescence measurement techniques. Measurements of time-resolved luminescence were also performed to examine the nature of the luminescence recombination under visible (470 nm) and IR (855 nm) stimulation. The results obtained by TL and optically stimulated techniques suggest that there may be deeper traps than previously observed in certain types of dental ceramic. Such traps may be less susceptible to optical and athermal fading than was reported in earlier studies. (author)

  7. The influence of Ag{sup 9+} ion irradiation on the structural, optical and luminescence properties of Sm{sup 3+} doped NaSrBO{sub 3}: Stability of color emission

    Energy Technology Data Exchange (ETDEWEB)

    Bedyal, A.K. [School of Physics, Shri Mata Vaishno Devi University, Katra 182320 - J& K (India); Kumar, Vinay, E-mail: vinaykumar@smvdu.ac.in [School of Physics, Shri Mata Vaishno Devi University, Katra 182320 -J& K (India); Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Singh, Vivek K. [School of Physics, Shri Mata Vaishno Devi University, Katra 182320 - J& K (India); Singh, Fouran; Lochab, S.P. [Inter University Accelerator Centre, Anura Asaf Ali Marg, P.O. Box 10502, New Delhi 110067 (India); Ntwaeaborwa, O.M.; Swart, H.C. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa)

    2015-05-15

    Highlights: •120 MeV Ag{sup 9+} ion irradiation modified the structure, optical and luminescence properties of NaSrBO{sub 3}: Sm{sup 3+} phosphor. •The phosphor is synthesized by the solid state reaction and combustion method. •Colour statibilty confirmed by CIE coordinates after ion irradiations. -- Abstract: This paper reports on the effect of 120 MeV Ag{sup 9+} ion irradiation on the structure, optical and luminescence properties of NaSr{sub 1−x}BO{sub 3}: xSm{sup 3+} (x = 0.5–2.5 mol.%) phosphor, synthesized by the solid state reaction and combustion method. The samples were irradiated with Ag{sup 9+} swift heavy ions (SHIs) using fluences of 1 × 10{sup 12} ions cm{sup −2}, 5 × 10{sup 12} ions cm{sup −2} and 1 × 10{sup 13} ions cm{sup −2}. The as-prepared as well as irradiated samples were characterized by X-ray diffraction (XRD), diffuse reflectance (DR) and photoluminescence (PL) techniques. After irradiation, the structure of the phosphor did not change except that the loss of crystallinity which may be due to the fragmentation caused by the SHI. DR spectra reflect a blue shift in the absorption band with increasing fluences, for phosphors prepared using both solid state reaction and combustion method, resulting in an increase in the band gap from 5.64 to 6.06 eV. The PL intensity of the phosphors was enhanced with an increase in ion fluences, with the samples prepared using a combustion method exhibiting prominent intensity. The CIE coordinates were calculated and they correspond to the shade of orange–red emission of the Sm{sup 3+} ions.

  8. Europium enabled luminescent nanoparticles for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Syamchand, S.S., E-mail: syamchand.ss@gmail.com; Sony, G., E-mail: emailtosony@gmail.com

    2015-09-15

    Lanthanide based nanoparticles are receiving great attention ought to their excellent luminescent and magnetic properties and find challenging biomedical applications. Among the luminescent lanthanide NPs, europium based NPs (Eu-NPs) are better candidates for immunoassay and imaging applications. The Eu-NPs have an edge over quantum dots (QDs) by means of their stable luminescence, long fluorescence lifetime, sharp emission peaks with narrow band width, lack of blinking and biocompatibility. This review surveys the synthesis and properties of a variety of Eu-NPs consolidated from different research articles, for their applications in medicine and biology. The exquisite luminescent properties of Eu-NPs are explored for developing biomedical applications such as immunoassay and bioimaging including multimodal imaging. The biomedical applications of Eu-NPs are mostly diagnostic in nature and mainly focus on various key analytes present in biological systems. The luminescent properties of europium enabled NPs are influenced by a number of factors such as the site symmetry, the metal nanoparticles, metal ions, quantum dots, surfactants, morphology of Eu-NPs, crystal defect, phenomena like antenna effect and physical parameters like temperature. Through this review we explore and assimilate all the factors which affect the luminescence in Eu-NPs and coil a new thread of parameters that control the luminescence in Eu-NPs, which would provide further insight in developing Eu-based nanoprobes for future biomedical prospects. - Highlights: • The review describes 14 major factors that influence the luminescence properties of europium enabled luminescent nanoparticles (Eu-NPs). • Surveys different types of europium containing nanoparticles that have been reported for their biomedical applications. • Eu-NPs are conveniently divided into four different categories, based on the type of the substrates involved. The four categories are (1) virgin Eu-substrate based NPs; (2

  9. How Stable Is Stable?

    Science.gov (United States)

    Baehr, Marie

    1994-01-01

    Provides a problem where students are asked to find the point at which a soda can floating in some liquid changes its equilibrium between stable and unstable as the soda is removed from the can. Requires use of Newton's first law, center of mass, Archimedes' principle, stable and unstable equilibrium, and buoyant force position. (MVL)

  10. Luminescence properties of Er3+ ions doped bismuth borate glasses for 1.53 \\xB5m broadband optical amplifiers

    Science.gov (United States)

    Mariyappan, M.; Suthanthirakumar, P.; Arunkumar, S.; Marimuthu, K.

    2017-05-01

    A new series of Er3+ ions doped bismuth borate glasses were prepared with the composition (40—x)B2O3 + 20Bi2O3+20Na2O+20CaF2+xEr2O3 (where x= 0.1, 0.25, 0.5, 1 and 2 in wt%). The spectroscopic behaviors of the titled glasses have been examined through absorption, luminescence and decay spectral analysis. Luminescence spectra along with the JO intensity parameters have been used to determine the various radiative properties like transition probability (A), stimulated emission cross-section (σp), lifetimes (τcal, τexp), branching ratios (βR) and effective bandwidth (Δλeff) for the 4S3/2 →4I15/2 and 4I13/2→4I15/2 emission transitions and the results were discussed and reported. By employing the McCumbar theory, absorption and emission cross-sections for the 4I13/2→4I15/2 transition (1.53 μm) were calculated for all the titled glasses. The decay curves of the 4I13/2 level have been measured and the fall in lifetime value with the increase in Er3+ ion content have been studied through the energy transfer process takes place between the nearby Er3+ ions.

  11. Non-aqueous sol-gel synthesis of ultra small persistent luminescence nanoparticles for near-infrared in vivo imaging.

    Science.gov (United States)

    Teston, Eliott; Richard, Sophie; Maldiney, Thomas; Lièvre, Nicole; Wang, Guillaume Yangshu; Motte, Laurence; Richard, Cyrille; Lalatonne, Yoann

    2015-05-11

    Ultra-small ZnGa2 O4 :Cr(3+) nanoparticles (6 nm) that exhibit near-infrared (NIR) persistent luminescence properties are synthesized by using a non-aqueous sol-gel method assisted by microwave irradiation. The nanoparticles are pegylated, leading to highly stable dispersions under physiological conditions. Preliminary in vivo studies show the high potential for these ultra-small ZnGa2 O4 :Cr(3+) nanoparticles to be used as in vivo optical nanotools as they emit without the need for in situ excitation and, thus, avoid the autofluorescence of tissues.

  12. Modeling Light Propagation in Luminescent Media

    Science.gov (United States)

    Sahin, Derya

    This study presents physical, computational and analytical modeling approaches for light propagation in luminescent random media. Two different approaches are used, namely (i) a statistical approach: Monte-Carlo simulations for photon transport and (ii) a deterministic approach: radiative transport theory. Both approaches account accurately for the multiple absorption and reemission of light at different wavelengths and for anisotropic luminescence. The deterministic approach is a generalization of radiative transport theory for solving inelastic scattering problems in random media. We use the radiative transport theory to study light propagation in luminescent media. Based on this theory, we also study the optically thick medium. Using perturbation methods, a corrected diffusion approximation with asymptotically accurate boundary conditions and a boundary layer solution are derived. The accuracy and the efficacy of this approach is verified for a plane-parallel slab problem. In particular, we apply these two approaches (MC and radiative transport theory) to model light propagation in semiconductor-based luminescent solar concentrators (LSCs). The computational results for both approaches are compared with each other and found to agree. The results of this dissertation present practical and reliable techniques to use for solving forward/inverse inelastic scattering problems arising in various research areas such as optics, biomedical engineering, nuclear engineering, solar science and material science.

  13. Luminescence from potassium feldspars stimulated by infrared and green light

    DEFF Research Database (Denmark)

    Duller, G.A.T.; Bøtter-Jensen, L.

    1993-01-01

    A series of experiments are reported which investigate stimulated luminescence from potassium feldspar. The aim is to provide a basic phenomenological description of the response of the material to stimulation by heat, infrared radiation (875 DELTA 80 nm) and a green light wavelength band from 5 15...... to 560 nm. Two conclusions are drawn: firstly it is suggested that the majority of the trapped charge responsible for the infrared stimulated luminescence signal does not give rise to a thermoluminescence signal, and secondly that a large traction of the two optically stimulated luminescence signals...

  14. Yellow luminescence of gallium nitride generated by carbon defect complexes.

    Science.gov (United States)

    Demchenko, D O; Diallo, I C; Reshchikov, M A

    2013-02-22

    We demonstrate that yellow luminescence often observed in both carbon-doped and pristine GaN is the result of electronic transitions via the C(N)-O(N) complex. In contrast to common isolated defects, the C(N)-O(N) complex is energetically favorable, and its calculated optical properties, such as absorption and emission energies, a zero phonon line, and the thermodynamic transition level, all show excellent agreement with measured luminescence data. Thus, by combining hybrid density functional theory and experimental measurements, we propose a solution to a long-standing problem of the GaN yellow luminescence.

  15. LUMINESCENCE OF CADMIUM SULFIDE QUANTUM DOTS IN FLUOROPHOSPHATE GLASSES

    OpenAIRE

    Z. O. Lipatova; E. V. Kolobkova; V. A. Aseev

    2015-01-01

    Cadmium sulfide quantum dots are perspective materials in optics, medicine, biology and optoelectronics. Fluorophosphate glasses, doped with cadmium sulfide quantum dots, were examined in the paper. Heat treatment led to the formation of quantum dots with diameters equal to 2.8 nm, 3.0 nm and 3.8 nm. In view of such changes in the quantum dots size the fundamental absorption edge shift and the luminescence band are being displaced to the long wavelengths. Luminescence lifetime has been fou...

  16. Chemically engineered persistent luminescence nanoprobes for bioimaging

    Science.gov (United States)

    Lécuyer, Thomas; Teston, Eliott; Ramirez-Garcia, Gonzalo; Maldiney, Thomas; Viana, Bruno; Seguin, Johanne; Mignet, Nathalie; Scherman, Daniel; Richard, Cyrille

    2016-01-01

    Imaging nanoprobes are a group of nanosized agents developed for providing improved contrast for bioimaging. Among various imaging probes, optical sensors capable of following biological events or progresses at the cellular and molecular levels are actually actively developed for early detection, accurate diagnosis, and monitoring of the treatment of diseases. The optical activities of nanoprobes can be tuned on demand by chemists by engineering their composition, size and surface nature. This review will focus on researches devoted to the conception of nanoprobes with particular optical properties, called persistent luminescence, and their use as new powerful bioimaging agents in preclinical assays. PMID:27877248

  17. Advanced synchronous luminescence system

    Science.gov (United States)

    Vo-Dinh, Tuan

    1997-01-01

    A method and apparatus for determining the condition of tissue or otherwise making chemical identifications includes exposing the sample to a light source, and using a synchronous luminescence system to produce a spectrum that can be analyzed for tissue condition.

  18. Structured luminescence conversion layer

    Science.gov (United States)

    Berben, Dirk; Antoniadis, Homer; Jermann, Frank; Krummacher, Benjamin Claus; Von Malm, Norwin; Zachau, Martin

    2012-12-11

    An apparatus device such as a light source is disclosed which has an OLED device and a structured luminescence conversion layer deposited on the substrate or transparent electrode of said OLED device and on the exterior of said OLED device. The structured luminescence conversion layer contains regions such as color-changing and non-color-changing regions with particular shapes arranged in a particular pattern.

  19. Influence of P{sub 2}O{sub 5} and Al{sub 2}O{sub 3} content on the structure of erbium-doped borosilicate glasses and on their physical, thermal, optical and luminescence properties

    Energy Technology Data Exchange (ETDEWEB)

    Bourhis, Kevin, E-mail: k.bourhis@argolight.com [Politecnico di Torino, DISAT, Istituto di Ingegneria e Fisica dei Materiali, Corso Duca degli Abruzzi 24, I-10129 Torino (Italy); Massera, Jonathan [Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FI-20500 Turku (Finland); Petit, Laeticia; Ihalainen, Heikki [nLIGHT Corporation, Sorronrinne 9, FI-08500 Lohja (Finland); Fargues, Alexandre; Cardinal, Thierry [CNRS, Université de Bordeaux, ISM, 351Cours de la Libération, F-33405 Talence (France); Hupa, Leena; Hupa, Mikko [Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FI-20500 Turku (Finland); Dussauze, Marc; Rodriguez, Vincent [CNRS, Université de Bordeaux, ICMCB, 87 Avenue du Dr Schweitzer, F-33608 Pessac (France); Boussard-Plédel, Catherine; Bureau, Bruno; Roiland, Claire [Equipe Verres et Céramiques, UMR-CNRS 6226, Inst. des Sciences chimiques de Rennes, Université de Rennes 1, 35042 Rennes CEDEX (France); Ferraris, Monica [Politecnico di Torino, DISAT, Istituto di Ingegneria e Fisica dei Materiali, Corso Duca degli Abruzzi 24, I-10129 Torino (Italy)

    2015-03-15

    Highlights: • Reorganization of the glass structure induced by the addition of P{sub 2}O{sub 5} or Al{sub 2}O{sub 3}. • Emission properties related to the presence of P or Al in the Er{sup 3+} coordination shell. • Declustering observed upon addition of P{sub 2}O{sub 5}. • No declustering upon addition of Al{sub 2}O{sub 3}. - Abstract: The effect of P{sub 2}O{sub 5} and/or Al{sub 2}O{sub 3} addition in Er-doped borosilicate glasses on the physical, thermal, optical, and luminescence properties is investigated. The changes in these glass properties are related to the glass structure modifications induced by the addition of P{sub 2}O{sub 5} and/or Al{sub 2}O{sub 3}, which were probed by FTIR, {sup 11}B MAS NMR and X-ray photoelectron spectroscopies. Variations of the polymerization degree of the silicate tetrahedra and modifications in the {sup [3]}B/{sup [4]}B ratio are explained by a charge compensation mechanism due to the formation of AlO{sub 4}, PO{sub 4} groups and the formation of Al-O-P linkages in the glass network. From the absorption and luminescence properties of the Er{sup 3+} ions at 980 nm and 1530 nm, declustering is suspected for the highest P{sub 2}O{sub 5} concentrations while for the highest Al{sub 2}O{sub 3} concentrations no declustering is observed.

  20. 荧光玻璃、热释光和光释光探测器性能比较%Comparison on Characteristics of Radiophotoluminescent Glass,Thermoluminescence and Optically Stimulated Luminescence

    Institute of Scientific and Technical Information of China (English)

    樊海军; 唐开勇; 崔辉; 刘正

    2011-01-01

    It is to review that the principle of radiophotoluminescence glass detectors( RPLCD) , thermolumines-cence detectors (TLD)and Optically Stimulated luminescence (OSL) detectors ,and compare their advantages and disadvantages and some recent developments in luminescence of detectors. The major advantage of RPLCD is long - term stability and capability of repeating readout. The major advantage of TLD and OSL detectors are high sensitivity, low detection threshold, good fading effect, good energy response after γ - ray irradiation (for materials with Zeff close to that of tissue) , resistance to high humidity and to high magnetic fields. Compare with IiF:Mg,Cu,P,however,the OSL of is very high sensitivity to visible light and relative high effective atomic number(10.2).%介绍了荧光玻璃探测器、热释光探测器和光释光探测器基本原理和近期发展,并总结了荧光玻璃、热释光探测器、光释光探测器的优缺点.荧光玻璃最大优点是长期稳定性好和可多次读取.热释光和光释光探测器具有灵敏度高、低探测阈、较好的稳定性和能量响应、环境适应性强等优点.但与LiF:Mg,Cu,P相比,α- Al2O3:C光释光探测器对可见光敏感和具有较高的有效原子序数(10.2).

  1. Discussions of Optical Stimulated Luminescence Dating about Colluvial Deposits in Lintong-chang'an Fault%临潼-长安断裂上断层崩积楔光释光测年的探讨

    Institute of Scientific and Technical Information of China (English)

    李晓妮; 田勤虎; 李高阳; 李苗; 李娟

    2011-01-01

    选择西安临潼-长安断裂带上韩峪乡范家村剖面的一个典型崩积楔样品进行测试.用3种不同的释光测试方法测出了9个不同的年龄数据.根据地层信息和矿物的释光生长曲线确定只有采用混合矿物简单多片再生法、纯石英矿物简单多片再生法以及纯石英矿物单片再生法的光释光测年法所得结果更接近于崩积楔的真实年龄.这些断层崩积楔年龄接近于围岩的形成年龄,并不能代表真正意义上的断层活动时代.因此,断层崩积楔年龄光释光测年结果无法给出该断层最真实的活动时代.%This article choosed Fanjiacun profile in Iintong-chang'an fault as a typical fault gouge samples testing and used three different methods to obtain nine different age data. According to stratum information and minerals luminescence growth curve, the paper determined only three dating method. They are mixed minerals multiple aliquot regenerative dose protocol, fine grained quartz multiple aliquot regenerative dose protocol and fine grained quartz single aliquot regenerative dose protocol. These fault wedge ages are close to collapse product of surrounding rock formation age but can't represent real fault activity era. So we conclude that optical stimulated luminescence age results of colluvial deposit can't give real activity age about fault.

  2. PNBE-supported metallopolymer-type optical materials through grafting of Zn-Ln (Ln = Nd, Yb or Er) benzimidazole complex monomers with efficient NIR luminescence

    Science.gov (United States)

    Liu, Lin; Li, Hongyan; Feng, Weixu; Fu, Guorui; Lü, Xingqiang; Wong, Wai-Kwok; Jones, Richard A.

    2017-02-01

    Through the ring-opening metathesis polymerization (ROMP) of norbornene (NBE) with each of obtained allyl-containing complex monomers [Zn(L)2(Py)Ln(NO3)3] (Ln = La, 1; Nd, 2; Yb, 3; Er, 4 or Gd, 5; HL = 4-allyl-2-(1H-benzo[d]imidazol-2-yl)-6-methoxyphenol; Py = pyridine), a series of metallopolymers Poly(NBE-co-[Zn(L)2Ln(Py)(NO3)3)]) were obtained, respectively. Especially for Poly(NBE-co-2) and Poly(NBE-co-3), covalently-bonded grafting endows significantly improved physical properties including efficient NIR luminescence (ΦNdL = 0.63% and ΦYbL = 1.43%) in solid state.

  3. Highly aqueous soluble CaF2:Ce/Tb nanocrystals: effect of surface functionalization on structural, optical band gap, and photoluminescence properties.

    Science.gov (United States)

    Ansari, Anees A; Parchur, Abdul K; Kumar, Brijesh; Rai, S B

    2016-12-01

    The design of nanostructured materials with highly stable water-dispersion and luminescence efficiency is an important concern in nanotechnology and nanomedicine. In this paper, we described the synthesis and distinct surface modification on the morphological structure and optical (optical absorption, band gap energy, excitation, emission, decay time, etc.) properties of highly crystalline water-dispersible CaF2:Ce/Tb nanocrystals (core-nanocrystals). The epitaxial growth of inert CaF2 and silica shell, respectively, on their surface forming as CaF2:Ce/Tb@CaF2 (core/shell) and CaF2:Ce/Tb@CaF2@SiO2 (core/shell/SiO2) nanoarchitecture. X-ray diffraction and transmission electron microscope image shows that the nanocrystals were in irregular spherical phase, highly crystalline (~20 nm) with narrow size distribution. The core/shell nanocrystals confirm that the surface coating is responsible in the change of symmetrical nanostructure, which was determined from the band gap energy and luminescent properties. It was found that an inert inorganic shell formation effectively enhances the luminescence efficiency and silica shell makes the nanocrystals highly water-dispersible. In addition, Ce(3+)/Tb(3+)-co-doped CaF2 nanocrystals show efficient energy transfer from Ce(3+) to Tb(3+) ion and strong green luminescence of Tb(3+) ion at 541 nm((5)D4→(7)F5). Luminescence decay curves of core and core/shell nanocrystals were fitted using mono and biexponential equations, and R (2) regression coefficient criteria were used to discriminate the goodness of the fitted model. The lifetime values for the core/shell nanocrystals are higher than core-nanocrystals. Considering the high stable water-dispersion and intensive luminescence emission in the visible region, these luminescent core/shell nanocrystals could be potential candidates for luminescent bio-imaging, optical bio-probe, displays, staining, and multianalyte optical sensing. A newly designed CaF2:Ce/Tb nanoparticles via

  4. Radio frequency phototube and optical clock: High resolution, high rate and highly stable single photon timing technique

    Energy Technology Data Exchange (ETDEWEB)

    Margaryan, Amur

    2011-10-01

    A new timing technique for single photons based on the radio frequency phototube and optical clock or femtosecond optical frequency comb generator is proposed. The technique has a 20 ps resolution for single photons, is capable of operating with MHz frequencies and achieving 10 fs instability level.

  5. Thermoluminescence and optically stimulated luminescence properties of Dy{sup 3+}-doped CaO–Al{sub 2}O{sub 3}–B{sub 2}O{sub 3}-based glasses

    Energy Technology Data Exchange (ETDEWEB)

    Yahaba, T., E-mail: takuma.yahaba.s1@dc.tohoku.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, 6-6-07 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579 (Japan); Fujimoto, Y. [Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, 6-6-07 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579 (Japan); Yanagida, T. [Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma 630-0192 (Japan); Koshimizu, M.; Tanaka, H.; Saeki, K.; Asai, K. [Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, 6-6-07 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579 (Japan)

    2017-02-01

    We developed Dy{sup 3+}-doped CaO–Al{sub 2}O{sub 3}–B{sub 2}O{sub 3} based glasses with Dy concentrations of 0.5, 1.0, and 2.0 mol% using a melt-quenching technique. The as-synthesized glasses were applicable as materials exhibiting thermoluminescence (TL) and optically stimulated luminescence (OSL). The optical and radiation response properties of the glasses were characterized. In the photoluminescence (PL) spectra, two emission bands due to the {sup 4}F{sub 9/2} → {sup 6}H{sub 15/2} and {sup 4}F{sub 9/2} → {sup 6}H{sub 13/2} transitions of Dy{sup 3+} were observed at 480 and 580 nm. In the OSL spectra, the emission band due to the {sup 4}F{sub 9/2} → {sup 6}H{sub 15/2} transition of Dy{sup 3+} was observed. Excellent TL and OSL responses were observed for dose ranges of 0.1–90 Gy. In addition, TL fading behavior was better than that of OSL in term of the long-time storage. These results indicate that the Dy{sup 3+}-doped CaO–Al{sub 2}O{sub 3}–B{sub 2}O{sub 3}-based glasses are applicable as TL materials.

  6. Effect of alkali metal oxides R2O (R=Na, K) on 1.53 μm luminescence of Er3+-doped Ga2O3-GeO2 glasses for optical amplification

    Institute of Scientific and Technical Information of China (English)

    赵营刚; 石冬梅

    2013-01-01

    This paper reported the thermal stability and spectroscopic properties of Ga2O3-GeO2-Na2O-K2O (GGNK) glasses doped with Er3+. The GGNK glasses were characterized by differential scanning calorimetry (DSC), Raman spectra, absorption and infra-red-visible fluorescence spectra. Measured DSC result showed that these glasses possessed an excellent stability (ΔT=188.6 oC). The relationship between glass composition and Judd-Ofelt intensity parameters and other optical properties of Er3+, such as the absorption and stimulated emission cross-sections, were clarified. Meanwhile an intense broadband 1.53-μm emission with a full width at half-maximum of 51 nm and peak emission cross-section of 9.32×10-21 cm2 of Er3+-doped GGNK glass was obtained upon 980 nm di-ode-laser excitation. Effects of K2O replacing Na2O on the thermal stability and spectroscopic properties were investigated. It was found that the incorporation of K2O into Er3+-doped Ga2O3-GeO2-Na2O glass could effectively improve the 1.53μm emission luminescence. The results showed that GGNK glass might be more attractive host material for their application in C-band optical fiber amplifiers.

  7. Thermoluminescence and optically stimulated luminescence properties of nanocrystalline Er{sup 3+} and Yb{sup 3+} doped Y{sub 3}Al{sub 5}O{sub 12} exposed to {beta}-rays

    Energy Technology Data Exchange (ETDEWEB)

    RodrIguez, R A [Universidad de Guadalajara en Lagos, Lagos de Moreno, Jalisco, 47460 (Mexico); Rosa, E de la [Centro de Investigaciones en Optica, A.P. 1-948, Leon, Gto. 37150 (Mexico); Salas, P [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, C.P. 07730, Mexico, D. F. (Mexico); Melendrez, R [Centro de Investigacion en Fisica, Universidad de Sonora, PO Box 5-088, Hermosillo, Sonora, 83190 (Mexico); Barboza-Flores, M [Centro de Investigacion en Fisica, Universidad de Sonora, PO Box 5-088, Hermosillo, Sonora, 83190 (Mexico)

    2005-11-07

    The thermoluminescence (TL) and optically stimulated luminescence (OSL) characterization of Er{sup 3+} and Yb{sup 3+} doped Y{sub 3}Al{sub 5}O{sub 12} nanocrystalline samples prepared by the precipitation process and exposed to {beta}-rays are discussed. The TL as well as the OSL were two orders of magnitude higher in Er{sup 3+} doped than in Yb{sup 3+} specimens. The charge trapping and the radiative thermally stimulated recombination processes in Y{sub 3}Al{sub 5}O{sub 12} : Er{sup 3+} involve four trapping states at 166, 243, 342 and 424 deg. C, but just two trapping levels at 219 and 413 deg. C for Y{sub 3}Al{sub 5}O{sub 12} : Yb{sup 3+} at a heating rate of 10 deg. C s{sup -1}. The photostimulation with 470 nm light causes in both phosphors a radiative recombination of the optically free charge carriers belonging to the same trapping states. The TL and the OSL as a function of radiation dose behaviour were linear in the 10-100 Gy dose range. The results provide evidence of the potential uses of these materials in radiation storage and dosimeter devices.

  8. Luminescence properties of a nanoporous freshwater diatom.

    Science.gov (United States)

    Goswami, Bondita; Choudhury, Amarjyoti; Buragohain, Alak K

    2012-01-01

    Freshwater diatom frustules show special optical properties. In this paper we observed luminescence properties of the freshwater diatom Cyclotella meneghiniana. To confirm the morphological properties we present scanning electron microscopy (SEM) images. X-ray diffraction (XRD) studies were carried out to visualize the structural properties of the frustules, confirming that silica present in diatom frustules crystallizes in an α-quartz structure. Study of the optical properties of the silica frustules of diatoms using ultra-violet-visible (UV-vis) spectroscopy and photoluminescence spectroscopy confirmed that the diatom C. meneghiniana shows luminescence in the blue region of the electromagnetic spectrum when irradiated with UV light. This property of diatoms can be exploited to obtain many applications in day-to-day life. Also, using time-resolved photoluminescence spectroscopy (TRPL) it was confirmed that this species of diatom shows bi-exponential decay.

  9. Monitoring Delamination of Thermal Barrier Coatings by Near-Infrared and Upconversion Luminescence Imaging

    Science.gov (United States)

    Eldridge, J. I.; Martin, R. E.; Singh, Jogender; Wolfe, Doug E.

    2008-01-01

    Previous work has demonstrated that TBC delamination can be monitored by incorporating a thin luminescent sublayer that produces greatly increased luminescence intensity from delaminated regions of the TBC. Initial efforts utilized visible-wavelength luminescence from either europium or erbium doped sublayers. This approach exhibited good sensitivity to delamination of electron-beam physical-vapor-deposited (EB-PVD) TBCs, but limited sensitivity to delamination of the more highly scattering plasma-sprayed TBCs due to stronger optical scattering and to interference by luminescence from rare-earth impurities. These difficulties have now been overcome by new strategies employing near-infrared (NIR) and upconversion luminescence imaging. NIR luminescence at 1550 nm was produced in an erbium plus ytterbium co-doped yttria-stabilized zirconia (YSZ) luminescent sublayer using 980-nm excitation. Compared to visible-wavelength luminescence, these NIR emission and excitation wavelengths are much more weakly scattered by the TBC and therefore show much improved depth-probing capabilities. In addition, two-photon upconversion luminescence excitation at 980 nm wavelength produces luminescence emission at 562 nm with near-zero fluorescence background and exceptional contrast for delamination indication. The ability to detect TBC delamination produced by Rockwell indentation and by furnace cycling is demonstrated for both EB-PVD and plasma-sprayed TBCs. The relative strengths of the NIR and upconversion luminescence methods for monitoring TBC delamination are discussed.

  10. Luminescence of erbium ions in tellurite glasses

    Energy Technology Data Exchange (ETDEWEB)

    Savikin, Alexander P.; Grishin, Igor A.; Sharkov, Valery V.; Budruev, Andrei V., E-mail: budruev@gmail.com

    2013-11-15

    Optical characteristics of new generation of tellurite glasses having high stability against crystallization have been studied. As the initial reagents for the glasses synthesis on the base of tellurium oxide (TeO{sub 2}) there were used such oxides as WO{sub 3}, MoO{sub 3}, La{sub 2}O{sub 3}, Li{sub 2}CO{sub 3}, ZnO—Bi{sub 2}O{sub 2}CO{sub 3} and active components such as high purity Er{sub 2}O{sub 3}, Yb{sub 2}O{sub 3}, ErF{sub 3} and YbF{sub 3}. Intensities of luminescence at 1.53 µm of the erbium ions were determined after excitation at 975 nm. Experimental data obtained have shown the possibility to use the studied glasses doped by Er{sup 3+} and Yb{sup 3+} as active elements for fiber and integrated optics. - Graphical abstract: In contrast to the case of ZBLAN glass the TeO{sub 2}–WO{sub 3} (Er{sup 3+}) glass has bright intensity of luminescence at 1.53 µm for erbium ions that should be caused by excitation at 975 nm. Experimental data obtained have shown the possibility to use the studied glasses doped by Er{sup 3+} and Yb{sup 3+} as active elements for fiber and integrated optics. Display Omitted - Highlights: • We examined changes in growth of luminescence in doubly-doped tellurite glasses. • We found that luminescence grows in two orders by using Er{sup 3+} and Yb{sup 3+} at 1.53 μm. • We see possibility to use those glasses as active elements for integrated optics.

  11. Thermoluminescent dosimetry and of optically stimulated luminescence of diamond films grown up by the chemical vapor deposition technique exposed to beta radiation; Dosimetria termoluminiscente y de luminiscencia opticamente estimulada de peliculas de diamante crecidas por la tecnica de DVQ expuestas a radiacion beta

    Energy Technology Data Exchange (ETDEWEB)

    Melendrez A, R.; Barboza F, M. [Centro de Investigacion en Fisica, Universidad de Sonora, A.P. 5-88, Hermosillo, Sonora, 83190 (Mexico)

    2002-07-01

    A study of the dosimetric properties through the thermoluminescence (Tl) and Optically stimulated luminescence (Lobe) in diamond films grown up by the chemical vapor deposition (Dq) techniques was realized.The films under study have thickness of 6, 12, 180 and 500 microns. The dose range was from 0 to 1.5 KGy, observing for the case of the thermoluminescent dosimetry a linear behavior in the range 0-300 Gy and a supra linearity effect in the range from 300-1500 Gy. For the case of the dosimetry by means of LOE a linear behavior in the range (0-300 Gy) without be enough for the saturation was observed, although some samples exhibit a linear behavior until 1500 Gy (6 microns). The irradiation was realized with a source of Strontium 90 of (40 mCi) and the photoestimulation for realizing the measures of LOE was realized using diodes emitting of laser light (470 nm) which generate until 50 MW/cm{sup 2}. The Tl peak which was used to realize the dosimetry such Tl as LOE was that located around 340 C degrees in the brilliance curve which presents another peaks centered around of 110, 190, and 340 C degrees, depending on the film. It was realized a study of the Tl signal drop and it was observed that after 3 hours the signal was stable reaching a decay of 15 %. the analysis of the drop in the Tl signal, immediately after to irradiate and after to photoestimulate with the blue light laser for observing the LOE, indicated that exists a fall in all the Tl peaks, decaying in greater proportion those of more low temperature. (Author)

  12. How the optical timing system,the longitudinal diagnostics and the associated feedback systems provide femtosecond stable operation at the FERMI free electron laser

    Institute of Scientific and Technical Information of China (English)

    Mario Ferianis; Enrico Allaria; Eugenio Ferrari; Giulio Gaio; Giuseppe Penco; Fabio Rossi; Marco Veronese

    2016-01-01

    FERMI, the seeded free electron laser(FEL) in operation in Italy, is providing the User Community with unique fully coherent radiation, in the wavelength range 100–4 nm. FERMI is the first FEL fully synchronized by means of optical fibers. The optical timing system ensures an ultra-stable phase reference to its distributed clients. Several femtosecond longitudinal diagnostics verify the achieved performance; the bunch length monitor(BLM) and the bunch arrival monitor(BAM) will be presented in this paper. Feedback systems play a crucial role to guarantee the needed longterm electron beam stability. A real-time infrastructure allows shot-to-shot communication between front-end computers and the servers. Orbit feedbacks are useful in machine tuning, whereas longitudinal feedbacks control electron energy,compression and arrival time. A flexible software framework allows a rapid implementation of heterogeneous multiinput–multi-output(MIMO) longitudinal loops simply by selecting the appropriate sensors and actuators.

  13. Luminescence from Porous Silicon

    Directory of Open Access Journals (Sweden)

    A. Gupta

    1998-01-01

    Full Text Available Recent observations of photoluminescene (PL and electroluminescence (EL from poroussilicon (PS have prompted many theoretical and experimental studies. Bulk crystalline Si is anindirect band gap material in which .recombination is dominated by non-radiative processes.Therefore, it cannot be used as light-emitting component in Si circuits. PS is a new material formed byanodisation ofsingle crystal Si wafers in hydro fluoric (liF solution. Luminescence from this materialis being explored for technological applications all over the world. The mechanism of luminescence isstill not well-understood. Several models have been proposed but still the facts about the strong lightemission at room temperature are unknown. This paper presents a review of the fabrication process andstudies on luminescent properties of PS. A hybrid model based on quantum confinement of carriers inthe nanometer size Si crystallites having a large number of surface states is suggested to explain theobserved properties.

  14. Testing the application of quartz and feldspar luminescence dating to MIS 5 Japanese marine deposits

    DEFF Research Database (Denmark)

    Thiel, Christine; Tsukamoto, Sumiko; Tokuyasu, Kayoko

    2015-01-01

    The applicability of both quartz and feldspar luminescence dating was tested on twenty-five samples from a marine succession now forming a coastal cliff at Oga Peninsula, Honshu Island, Japan. The quartz optically stimulated luminescence (OSL) signal shows thermal instability and linear modulated...

  15. Homogeneous broadening effect on temperature dependence of green upconversion luminescence in erbium doped fibers

    NARCIS (Netherlands)

    Egatz-Gomez, A.; Calderon, Oscar G.; Melle, Sonia; Carreno, F.; Anton, M. A.; Gort, Elske M.

    We study the green upconversion luminescence of Er3+ ions in an aluminosilicate optical fiber upon near infrared excitation at 787 nm. The dependence of the upconversion luminescence on temperature has been determined. As temperature drops from room to cryogenic temperatures, the upconversion green

  16. Luminescent properties of fluorophosphate glasses with molecular cadmium selenide clusters

    Science.gov (United States)

    Kolobkova, E. V.; Kukushkin, D. S.; Nikonorov, N. V.; Sidorov, A. I.; Shakhverdov, T. A.

    2015-02-01

    It is experimentally shown that, prior to the formation of CdSe quantum dots in fluorophosphate glasses with cadmium and selenium ions in the process of synthesis, subnanosized molecular clusters (CdSe) n are formed, which exhibit luminescence in the visible spectral region upon UV excitation. Heat treatment of the glasses increases the size of molecular clusters and makes their optical properties closer to the optical properties of CdSe semiconductor quantum dots. An increase in the sample temperature from 20 to 250°C leads to reversible thermal quenching of the luminescence.

  17. High-precision Distribution of Highly-stable Optical Pulse Trains with Sub-10-fs Timing Jitter

    CERN Document Server

    Ning, B; Hou, D; Wu, J T; Li, Z B; Zhao, J Y

    2014-01-01

    High-precision optical pulse trains distribution via fibre links has made huge impacts in many fields. In most published works, the accuracies are still fundamentally limited by some unavoidable noises, such as thermal and shot noise from conventional photodiodes, thermal noise from mixers. Here, we demonstrate a new high-precision timing distribution system by using highly-precision phase detector to overcome the limitations. Instead of using photodiodes and microwave mixers, we use several fibre Sagnac-loop-based optical-microwave phase detectors to realize optical-electrical conversion and phase measurements, for suppressing the noises and achieving ultra-high accuracy. A 10-km fibre link distribution experiment shows our system provides a residual instability at the level of 4.6*10-15@1-s and 6.1*10-18@10000-s, with an integrated timing jitter as low as 3.8 fs in a bandwidth of 1 Hz to 100 KHz. This low instability and timing jitter makes it possible that our system can be used in the optical clock distri...

  18. All-optical flip-flop operation based on asymmetric active-multimode interferometer bi-stable laser diodes

    DEFF Research Database (Denmark)

    Jiang, H.; Chaen, Y.; Hagio, T.;

    2011-01-01

    We demonstrate fast and low energy all optical flip-flop devices based on asymmetric active-multimode interferometer using high-mesa waveguide structure. The implemented devices showed high speed alloptical flip-flop operation with 25ps long pulses. The rising and falling times of the output sign...

  19. Measurement of Tumor Dose Using Optically Stimulated Luminescence Detectors (OSLDs) and Ionization Chambers for Primary and Metastatic Lymph Node Cancers with Head and Neck: Comparison of Beam Spoiler and Bolus

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Ok [Dept. of Radiotechnology, Wonkwang Health Science University, Iksan (Korea, Republic of); Lee, Jae Seung [Dept. of Physics, Soonchunhyang University, Seoul (Korea, Republic of); Jeong, Dong Hyeok [Research center, Dongnam Inst. of Radiological and Medical Science, Busan (Korea, Republic of)

    2011-09-15

    This study conducts cross-comparison through verification of treatment planning of using beam spoiler and bolus, according to the dose variation of different tumor bed and metastatic lymph node cancers, against ionization and optically stimulated luminescence detectors(OSLDs), in head and neck radiotherapy. Verification of treatment planning examined the feasibility of inserting detectors through simulated solid dry water slabs under identical irradiated conditions from treatment planning system to measure beam spoiler and 0.5, 1 cm bolus. In addition, two detectors were cross-compared for verification of treatment planning accuracy and reliability within {+-} 2%. The study found that, given a beam spoiler thickness of 0.5 cm and beam spoiler-to-skin distance of 10 cm subjected to optimal dose distribution given for metastatic lymph node cancers, the bolus low-level skin dose was less, and the tumor bed dose reduced slightly. Additionally, two detectors were cross-compared for accuracy within {+-} 1%. Accordingly, The use of beam spoiler was determined that reduces skin side effects and can deliver an optimal dose distribution for tumor, and to apply to future clinical studies should be performed.

  20. Influence of Nanosized Silicon Oxide on the Luminescent Properties of ZnO Nanoparticles

    Directory of Open Access Journals (Sweden)

    Vitaliy Shvalagin

    2016-01-01

    Full Text Available For practical use of nanosized zinc oxide as the phosphor its luminescence quantum yields should be maximized. The aim of this work was to enhance luminescent properties of ZnO nanoparticles and obtain high-luminescent ZnO/SiO2 composites using simpler approaches to colloidal synthesis. The luminescence intensity of zinc oxide nanoparticles was increased about 3 times by addition of silica nanocrystals to the source solutions during the synthesis of ZnO nanoparticles. Then the quantum yield of luminescence of the obtained ZnO/SiO2 composites is more than 30%. Such an impact of silica is suggested to be caused by the distribution of ZnO nanocrystals on the surface of silica, which reduces the probability of separation of photogenerated charges between the zinc oxide nanoparticles of different sizes, and as a consequence, there is a significant increase of the luminescence intensity of ZnO nanoparticles. This way of increasing nano-ZnO luminescence intensity facilitates its use in a variety of devices, including optical ultraviolet and visible screens, luminescent markers, antibacterial coatings, luminescent solar concentrators, luminescent inks for security printing, and food packaging with abilities of informing consumers about the quality and safety of the packaged product.

  1. Distinguishing between ultrafast optical harmonic generation and multi-photon-induced luminescence from ZnO thin films by interferometric frequency-resolved autocorrelation microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Slawa; Mascheck, Manfred; Silies, Martin [Carl-von-Ossietzky-Universitaet, Oldenburg (Germany); Yatsui, Takashi; Kitamura, Kokoro; Ohtsu, Motoichi; Lienau, Christoph [University of Tokyo (Japan)

    2011-07-01

    The nonlinear optical properties of a thin ZnO film are studied using interferometric frequency-resolved autocorrelation (IFRAC) microscopy. By exciting the film with 6-fs, below-bandgap laser pulses at 800nm focused to a spot size of 1 {mu}m two emission bands in the blue and bluegreen spectral region with distinctly different coherence properties can be detected. We show that an analysis of the wavelength-dependence of the interference fringes in the IFRAC signal allows for an unambiguous assignment of these bands as coherent second harmonic emission and incoherent, multiphoton-induced photoluminescence, respectively. More generally our analysis shows that IFRAC allows for a complete characterization of the coherence properties of the nonlinear optical emission from nanostructures in a single-beam experiment. Since this technique combines a very high temporal and spatial resolution we anticipate broad applications in nonlinear nano-optics.

  2. On the development of multifunctional luminescent supramolecular hydrogel of gold and egg white

    Science.gov (United States)

    Patra, Sudeshna; Ravulapalli, Sathyavathi; Hahm, Myung Gwan; Tadi, Kiran Kumar; Narayanan, Tharangattu N.

    2016-10-01

    Highly stable, luminescent, and printable/paintable supramolecular egg white hydrogel-based surface enhanced Raman scattering (SERS) matrix is created by an in situ synthesis of gold clusters inside a luminescent egg white hydrogel (Au-Gel). The synthesis of stable luminescent egg-white-based hydrogel, where the hydrogel can act as a three dimensional (3D) matrix, using a simple cross-linking chemistry, has promising application in the biomedical field including in 3D cell culturing. Furthermore, this functional hydrogel is demonstrated for micromolar-level detection of Rhodamine 6G using the SERS technique, where Au-Gel is painted over a flexible cellulose pad.

  3. Optically stimulated luminescence and thermoluminescence in CVD diamond and dosimetric evaluation in fields of ionizing radiation; Luminiscencia opticamente estimulada y termoluminiscencia en diamante DQV y evaluacion dosimetrica en campos de radiacion ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Barboza F, M.; Chernov, V.; Pedroza M, M. [Centro de Investigaciones en Fisica, Universidad de Sonora, A.P. 5-088, 83190 Hermosillo, Sonora (Mexico); Schreck, M. [Universitat Augsburg, Institut fur Physik D-86135, Augsburg (Germany); Preciado F, S.; Melendrez, R. [Universidad de Sonora, A.P. 130, 83000 Hermosillo, Sonora (Mexico)

    2006-07-01

    The optically stimulated luminescence (OSL) results a highly appropriate dosimetric technique for readings of absorbed radiation 'in alive' and 'in situ', as well as in real time. The CVD diamond on the other hand presents excellent qualities like radiation reader thanks to its reproducibility, radiation resistance, biocompatibility and non toxicity. The present work studies the answer of two diamond films pure and polluted with nitrogen (750 ppm) grown by the Chemical Vapor Deposition method (CVD) on silicon substrate (001) irradiated with beta (Sr-90) in the 0.833-100 Gy interval. The optical stimulation was carried out by 40 seconds with infrared laser (830 nm, 0.36 W/cm{sup 2}) and the filter BG-39 (300-600 nm) coupled the PM. The intensity and the decay of the hyperbolic type of the LOE curves were similar in both samples, for the non doped diamond were observed trapping states in 200-380 C being compared with those that it presents the polluted diamond with nitrogen in 80-277 C. The dosimetric behavior in the pure sample is observed lineal in two regions 0-16 Gy and in 30-100 Gy, only the doped sample didn't present linearity in the all range of the studied dose. The advantage is stood out of LOE on TL because the first one not requires of thermal stimulation in such a way that is more appropriate to detect and to measure radiation doses in biomedicine. (Author)

  4. Preparation and thermally stable luminescence properties of a new blue Sr{sub 5}Cl{sub 0.75}F{sub 0.25}(PO{sub 4}){sub 3}: Eu{sup 2+} phosphor for WLEDs

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Zhan-Chao, E-mail: wuzhan_chao@163.com; Wang, Shuai; Liu, Jie, E-mail: zsuliujie@163.com; Yin, Jin-Hua; Kuang, Shao-Ping

    2015-09-25

    Highlights: • A new blue phosphor Sr{sub 5}Cl{sub 0.75}F{sub 0.25}(PO{sub 4}){sub 3}: Eu{sup 2+} was prepared at 800 °C. • The broad excitation band of the phosphor matches well with n-UV LED chips. • The phosphor possesses higher thermal quenching stability than BAM. • A bright blue LED was fabricated by combination of n-UV chip and the phosphor. - Abstract: A series of new blue-emitting phosphors Sr{sub 5(1−x)}Cl{sub 0.75}F{sub 0.25}(PO{sub 4}){sub 3}: 5xEu{sup 2+} (x = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 mol%) were synthesized by high-temperature solid state reaction. X-ray powder diffraction (XRD) and field-emission scanning electron microscope (FE-SEM) were used to characterize the crystal structure and micro-morphology of the prepared samples. The photoluminescence properties of these phosphors were investigated by excitation and emission spectra. The effect of Eu{sup 2+} concentration on emission of the phosphor was investigated and the concentration quenching mechanism was discussed in detail. Also, the temperature-dependence luminescence properties of Sr{sub 5}Cl{sub 0.75}F{sub 0.25}(PO{sub 4}){sub 3}: Eu{sup 2+} were compared with those of the commercial blue phosphor BaMgAl{sub 10}O{sub 17}: Eu{sup 2+} (BAM). With the increase of temperature, the emission band exhibited blue shift and decreasing emission intensities. The phosphor Sr{sub 5}Cl{sub 0.75}F{sub 0.25}(PO{sub 4}){sub 3}: Eu{sup 2+} possesses higher thermal stability than BAM. Furthermore, a bright blue LED was fabricated by combination of n-UV InGaN chip and the phosphor. The results reveal that Sr{sub 5}Cl{sub 0.75}F{sub 0.25}(PO{sub 4}){sub 3}: Eu{sup 2+} is a potential blue phosphor for n-UV-pumped white light-emitting-diodes (WLEDs)

  5. CCD Luminescence Camera

    Science.gov (United States)

    Janesick, James R.; Elliott, Tom

    1987-01-01

    New diagnostic tool used to understand performance and failures of microelectronic devices. Microscope integrated to low-noise charge-coupled-device (CCD) camera to produce new instrument for analyzing performance and failures of microelectronics devices that emit infrared light during operation. CCD camera also used to indentify very clearly parts that have failed where luminescence typically found.

  6. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    1997-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible luminescenc

  7. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    1997-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible

  8. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    2001-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible luminescenc

  9. Analysis of proton scattering of stable and exotic light nuclei using an energy-dependent microscopic optical potential

    Directory of Open Access Journals (Sweden)

    Maridi H. M.

    2016-01-01

    Full Text Available The proton elastic scattering off the 9,10,11,12Be isotopes at a wide energy range from 3 to 200 MeV/nucleon is analyzed using the optical model with the partial-wave expansion method. The microscopic optical potential (OP is taken within the single-folding model. The density- and isospin-dependent M3YParis nucleon-nucleon (NN interaction is used for the real part and the NN-scattering amplitude of the highenergy approximation for the imaginary one. The cross-section data are reproduced well at energies up to 100 MeV/nucleon by use of the partial-wave expansion. For higher energies, the eikonal approximation is successfully used. The volume integrals of the OP parts have systematic energy dependencies and they can be parameterized as functions of energy. From these parametrization, an energy-dependent OP can be obtained.

  10. Electron Lenses for Experiments on Nonlinear Dynamics with Wide Stable Tune Spreads in the Fermilab Integrable Optics Test Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Stancari, G. [Fermilab; Carlson, K. [Fermilab; McGee, M. W. [Fermilab; Nobrega, L. E. [Fermilab; Romanov, A. L. [Fermilab; Ruan, J. [Fermilab; Valishev, A. [Fermilab; Noll, D. [Frankfurt U.

    2015-06-01

    Recent developments in the study of integrable Hamiltonian systems have led to nonlinear accelerator lattice designs with two transverse invariants. These lattices may drastically improve the performance of high-power machines, providing wide tune spreads and Landau damping to protect the beam from instabilities, while preserving dynamic aperture. To test the feasibility of these concepts, the Integrable Optics Test Accelerator (IOTA) is being designed and built at Fermilab. One way to obtain a nonlinear integrable lattice is by using the fields generated by a magnetically confined electron beam (electron lens) overlapping with the circulating beam. The parameters of the required device are similar to the ones of existing electron lenses. We present theory, numerical simulations, and first design studies of electron lenses for nonlinear integrable optics.

  11. Luminescent 1-hydroxy-2-pyridinone chelates of lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, Kenneth N.; Xu, Jide; Moore, Evan G.; Werner, Eric J.

    2017-01-31

    The present invention provides luminescent complexes between a lanthanide ion and an organic ligand which contains 1,2-hydroxypyridinone units. The complexes of the invention are stable in aqueous solutions and are useful as molecular probes, for example in medical diagnostics and bioanalytical assay systems. The invention also provides methods of using the complexes of the invention.

  12. Luminescent 1-hydroxy-2-pyridinone chelates of lanthanides

    Science.gov (United States)

    Raymond, Kenneth N.; Xu, Jide; Moore, Evan G.; Werner, Eric J.

    2013-10-15

    The present invention provides luminescent complexes between a lanthanide ion and an organic ligand which contains 1,2-hydroxypyridinone units. The complexes of the invention are stable in aqueous solutions and are useful as molecular probes, for example in medical diagnostics and bioanalytical assay systems. The invention also provides methods of using the complexes of the invention.

  13. New luminescence measurement facilities in retrospective dosimetry

    DEFF Research Database (Denmark)

    Lapp, Torben; Jain, Mayank; Thomsen, Kristina Jørkov

    2012-01-01

    thermoelectrically cooled NIR sensitive PMT (detection window peak at 855 nm, FWHM 27 nm). Software and electronics have been modified to allow standard TL and OSL measurements in the same sequence as RL measurements. Together with a new bleaching source based on a high-power UV LED (395 nm; 700 mW/cm2......This paper gives a review of recent developments in luminescence measurement facilities on the Risø TL/OSL reader including radio-luminescence (RL), exo-electron and violet stimulation attachments, and a method for characterising and if necessary correcting for beta irradiation source non......-uniformity.We first describe improvements to the existing RL option to allow near infra-red detection (NIR) during irradiation by the built-in 90Sr/90Y beta source. The RL optical signal is collected by a liquid light guide through an F34-901 interference filter and detection is based on a dedicated...

  14. Modeling and simulation of luminescence detection platforms.

    Science.gov (United States)

    Salama, Khaled; Eltoukhy, Helmy; Hassibi, Arjang; El-Gamal, Abbas

    2004-06-15

    Motivated by the design of an integrated CMOS-based detection platform, a simulation model for CCD and CMOS imager-based luminescence detection systems is developed. The model comprises four parts. The first portion models the process of photon flux generation from luminescence probes using ATP-based and luciferase label-based assay kinetics. An optics simulator is then used to compute the incident photon flux on the imaging plane for a given photon flux and system geometry. Subsequently, the output image is computed using a detailed imaging sensor model that accounts for photodetector spectral response, dark current, conversion gain, and various noise sources. Finally, signal processing algorithms are applied to the image to enhance detection reliability and hence increase the overall system throughput. To validate the model, simulation results are compared to experimental results obtained from a CCD-based system that was built to emulate the integrated CMOS-based platform.

  15. High-speed highly temperature stable 980 nm VCSELs operating at 25 Gb/s at up to 85 °C for short reach optical interconnects

    Science.gov (United States)

    Mutig, Alex; Lott, James A.; Blokhin, Sergey A.; Moser, Philip; Wolf, Philip; Hofmann, Werner; Nadtochiy, Alexey M.; Bimberg, Dieter

    2011-03-01

    The progressive penetration of optical communication links into traditional copper interconnect markets greatly expands the applications of vertical cavity surface emitting lasers (VCSELs) for the next-generation of board-to-board, moduleto- module, chip-to-chip, and on-chip optical interconnects. Stability of the VCSEL parameters at high temperatures is indispensable for such applications, since these lasers typically reside directly on or near integrated circuit chips. Here we present 980 nm oxide-confined VCSELs operating error-free at bit rates up to 25 Gbit/s at temperatures as high as 85 °C without adjustment of the drive current and peak-to-peak modulation voltage. The driver design is therefore simplified and the power consumption of the driver electronics is lowered, reducing the production and operational costs. Small and large signal modulation experiments at various temperatures from 20 up to 85 °C for lasers with different oxide aperture diameters are presented in order to analyze the physical processes controlling the performance of the VCSELs. Temperature insensitive maximum -3 dB bandwidths of around 13-15 GHz for VCSELs with aperture diameters of 10 μm and corresponding parasitic cut-off frequencies exceeding 22 GHz are observed. Presented results demonstrate the suitability of our VCSELs for practical high speed and high temperature stable short-reach optical links.

  16. Graphics processing unit aided highly stable real-time spectral-domain optical coherence tomography at 1375 nm based on dual-coupled-line subtraction

    Science.gov (United States)

    Kim, Ji-hyun; Han, Jae-Ho; Jeong, Jichai

    2013-04-01

    We have proposed and demonstrated a highly stable spectral-domain optical coherence tomography (SD-OCT) system based on dual-coupled-line subtraction. The proposed system achieved an ultrahigh axial resolution of 5 μm by combining four kinds of spectrally shifted superluminescent diodes at 1375 nm. Using the dual-coupled-line subtraction method, we made the system insensitive to fluctuations of the optical intensity that can possibly arise in various clinical and experimental conditions. The imaging stability was verified by perturbing the intensity by bending an optical fiber, our system being the only one to reduce the noise among the conventional systems. Also, the proposed method required less computational complexity than conventional mean- and median-line subtraction. The real-time SD-OCT scheme was implemented by graphics processing unit aided signal processing. This is the first reported reduction method for A-line-wise fixed-pattern noise in a single-shot image without estimating the DC component.

  17. Time-resolved luminescence from quartz: An overview of contemporary developments and applications

    Energy Technology Data Exchange (ETDEWEB)

    Chithambo, M.L., E-mail: m.chithambo@ru.ac.za [Department of Physics and Electronics, Rhodes University, PO BOX 94, Grahamstown 6140 (South Africa); Ankjærgaard, C. [Soil Geography and Landscape Group, Wageningen University Netherlands Centre for Luminescence Dating, Droevendaalsesteeg 3, 6708 PB Wageningen, The Netherlands (Netherlands); Pagonis, V. [McDaniel College, Physics Department, Westminster, MD 21157 (United States)

    2016-01-15

    Time-resolved optical stimulation of luminescence has become established as a key method for measurement of optically stimulated luminescence from quartz, feldspar and α-Al{sub 2}O{sub 3}:C, all materials of interest in dosimetry. The aim of time-resolved optical stimulation is to separate in time the stimulation and emission of luminescence. The luminescence is stimulated from a sample using a brief light pulse and the emission monitored during stimulation in the presence of scattered stimulating light or after pulsing, over photomultiplier noise only. Although the use of the method in retrospective dosimetry has been somewhat limited, the technique has been successfully applied to study mechanisms in the processes leading up to luminescence emission. The main means for this has been the temperature dependence of the luminescence intensity as well as the luminescence lifetimes determined from time-resolved luminescence spectra. In this paper we review some key developments in theory and applications to quartz including methods of evaluating lifetimes, techniques of evaluating kinetic parameters using both the dependence of luminescence intensity and lifetime on measurement temperature, and of lifetimes on annealing temperature. We then provide an overview of some notable applications such as separation of quartz signals from a quartz–feldspar admixture and the utility of the dynamic throughput, a measure of luminescence measured as a function of the pulse width. The paper concludes with some suggestions of areas where further exploration would advance understanding of dynamics of luminescence in quartz and help address some outstanding problems in its application.

  18. Luminescence sensitivity changes in quartz as a result of annealing

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Agersnap Larsen, N.; Mejdahl, V.

    1995-01-01

    Retrospective dosimetry using optically stimulated luminescence (OSL) on quartz extracted from (for example) bricks needs to account for strong OSL sensitivity changes that are known to occur depending on the previous thermal treatment of the sample. Non-heated quartz exhibits OSL orders of magni......Retrospective dosimetry using optically stimulated luminescence (OSL) on quartz extracted from (for example) bricks needs to account for strong OSL sensitivity changes that are known to occur depending on the previous thermal treatment of the sample. Non-heated quartz exhibits OSL orders...... of magnitude less per unit radiation than that for heated material. The reason these temperature-induced sensitivity changes occur in quartz is presently not well understood. This phenomenon is also seen in the related area of luminescence dating in which sedimentary quartz and quartz from heated...

  19. Lanthanide-doped luminescent nanomaterials from fundamentals to bioapplications

    CERN Document Server

    Chen, Xueyuan; Tu, Datao

    2014-01-01

    Lanthanide-Doped Luminescent Nanomaterials reviews the latest advances in the development of lanthanide-doped luminescent inorganic nanoparticles for potential bioapplications. This book covers the chemical and physical fundamentals of these nanoparticles, such as the controlled synthesis methodology, surface modification chemistry, optical physics, and their promising applications in diverse bioassays, with an emphasis on heterogeneous and homogeneous in-vitro biodetection of tumor biomarkers. This book is intended for those readers who are interested in systematically understanding the materials design strategy, optical behavior of lanthanide ions, and practical bioapplications of lanthanide nanoparticles. It primarily focuses on the interdisciplinary frontiers in chemistry, physics and biological aspects of luminescent nanomaterials. All chapters were written by scientists active in this field and for a broad audience, providing both beginners and advanced researchers with comprehensive information on the ...

  20. Infrared spectroscopy and secondary ion mass spectrometry of luminescent, nonluminescent, and metal quenched porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Hilliard, J.; Andsager, D.; Abu Hassan, L.; Nayfeh, H.M.; Nayfeh, M.H. (Department of Physics, University of Illinois at Urbana-Champaign, 1110 W. Green Street, Urbana, Illinois 61801 (United States))

    1994-08-15

    Porous silicon with varying optical properties (luminescent, nonluminescent, and metal quenched) is investigated by transmission infrared (IR) spectroscopy and secondary ion mass spectrometry (SIMS). SIMS and transmission IR data are presented which show a lack of correlation between the optical properties of similarly prepared luminescent and nonluminescent porous silicon samples and the concentrations of the chemical elements and bonds detected therein. Similar results are obtained for a comparison of IR spectra before and after dissolving the topmost layers ([similar to]2000 A) of a luminescent sample in a KOH solution, exposing the nonluminescent porous material below. Finally, IR and SIMS results for luminescent porous silicon quenched by metal ion solutions show a large increase in oxygen after quenching, but it is argued that the increased oxygen is unlikely to be directly responsible for the quenching of luminescence.

  1. A robust feldspar luminescence dating method for Middle and Late Pleistocene sediments

    DEFF Research Database (Denmark)

    Buylaert, Jan-Pieter; Jain, Mayank; Murray, Andrew S.

    2012-01-01

    Luminescence dating is used extensively to provide absolute chronologies for Late Pleistocene sediments. Nowadays, most optical dates are based on quartz optically stimulated luminescence (OSL). However, the application of this signal is usually limited to the last ~100 ka because of saturation...... of the quartz luminescence signal with dose. In contrast, the feldspar infrared stimulated luminescence (IRSL) dose–response curve grows to much higher doses; this has the potential to extend the datable age range by a factor of 4–5 compared with quartz OSL. However, it has been known for several decades...... is widely applicable (feldspar of appropriate luminescence behaviour is even more ubiquitous than quartz). These characteristics make this a method of great importance for the dating of Middle and Late Pleistocene deposits....

  2. Luminescent molecular rods - transition-metal alkynyl complexes.

    Science.gov (United States)

    Yam, Vivian Wing-Wah; Wong, Keith Man-Chung

    2005-01-01

    A number of transition-metal complexes have been reported to exhibit rich luminescence, usually originating from phosphorescence. Such luminescence properties of the triplet excited state with a large Stoke's shift, long lifetime, high luminescence quantum yield as well as lower excitation energy, are envisaged to serve as an ideal candidate in the area of potential applications for chemosensors, dye-sensitized solar cells, flat panel displays, optics, new materials and biological sciences. Organic alkynes (poly-ynes), with extended or conjugatedπ-systems and rigid structure with linear geometry, have become a significant research area due to their novel electronic and physical properties and their potential applications in nanotechnology. Owing to the presence of unsaturated sp-hybridized carbon atoms, the alkynyl unit can serve as a versatile building block in the construction of alkynyl transition-metal complexes, not only throughσ-bonding but also viaπ-bonding interactions. By incorporation of linear alkynyl groups into luminescent transition-metal complexes, the alkynyl moiety with goodσ-donor,π-donor andπ-acceptor abilities is envisaged to tune or perturb the emission behaviors, including emission energy (color), intensity and lifetime by its role as an auxiliary ligand as well as to govern the emission origin from its direct involvement. This review summarizes recent efforts on the synthesis of luminescent rod-like alkynyl complexes with different classes of transition metals and details the effects of the introduction of alkynyl groups on the luminescence properties of the complexes.

  3. Up-converting NaYF4:0.1%Tm3+, 20%Yb3+nanoparticles as luminescent labels for deep-tissue optical imaging

    Institute of Scientific and Technical Information of China (English)

    A. Gnach; K. Prorok; M. Misiak; B. Cichy; A. Bednarkiewicz

    2014-01-01

    Optical imaging plays an important role in biomedical research being extremely useful for early detection, screening and image-guided therapy. Lanthanide-doped up-converting nanoparticles were ideally suited for bioimaging because they could be ex-cited in near infrared (NIR) and emit in NIR or visible (VIS). Here, we compared lanthanide doped up-converting NaYF4 and organic fluorophores for application in deep-tissue imaging. For that purpose-tissue phantoms mimicking the natural properties of light scat-tering by living tissues were prepared. The studies allowed to quantitatively compare optical resolution of different fluorescent com-pounds, revealing that the NIR photoexcitation was favorable over conventional UV photoexcitation.

  4. Highly stable polymer coated nano-clustered silver plates: a multimodal optical contrast agent for biomedical imaging.

    Science.gov (United States)

    Ray, Aniruddha; Mukundan, Ananya; Xie, Zhixing; Karamchand, Leshern; Wang, Xueding; Kopelman, Raoul

    2014-11-07

    Here, we present a new optical contrast agent based on silver nanoplate clusters embedded inside of a polymer nano matrix. Unlike nanosphere clusters, which have been well studied, nanoplate clusters have unique properties due to the different possible orientations of interaction between the individual plates, resulting in a significant broadening of the absorption spectra. These nanoclusters were immobilized inside of a polymer cladding so as to maintain their stability and optical properties under in vivo conditions. The polymer-coated silver nanoplate clusters show a lower toxicity compared to the uncoated nanoparticles. At high nanoparticle concentrations, cell death occurs mostly due to apoptosis. These nanoparticles were used for targeted fluorescence imaging in a rat glioma cell line by incorporating a fluorescent dye into the matrix, followed by conjugation of a tumor targeting an F3 peptide. We further used these nanoparticles as photoacoustic contrast agents in vivo to enhance the contrast of the vasculature structures in a rat ear model. We observed a contrast enhancement of over 90% following the nanoparticle injection. It is also shown that these NPs can serve as efficient contrast agents, with specific targeting abilities for broadband multimodal imaging that are usable for diagnostic applications and that extend into use as therapeutic agents as well.

  5. Highly stable polymer coated nano-clustered silver plates: a multimodal optical contrast agent for biomedical imaging

    Science.gov (United States)

    Ray, Aniruddha; Mukundan, Ananya; Xie, Zhixing; Karamchand, Leshern; Wang, Xueding; Kopelman, Raoul

    2014-11-01

    Here, we present a new optical contrast agent based on silver nanoplate clusters embedded inside of a polymer nano matrix. Unlike nanosphere clusters, which have been well studied, nanoplate clusters have unique properties due to the different possible orientations of interaction between the individual plates, resulting in a significant broadening of the absorption spectra. These nanoclusters were immobilized inside of a polymer cladding so as to maintain their stability and optical properties under in vivo conditions. The polymer-coated silver nanoplate clusters show a lower toxicity compared to the uncoated nanoparticles. At high nanoparticle concentrations, cell death occurs mostly due to apoptosis. These nanoparticles were used for targeted fluorescence imaging in a rat glioma cell line by incorporating a fluorescent dye into the matrix, followed by conjugation of a tumor targeting an F3 peptide. We further used these nanoparticles as photoacoustic contrast agents in vivo to enhance the contrast of the vasculature structures in a rat ear model. We observed a contrast enhancement of over 90% following the nanoparticle injection. It is also shown that these NPs can serve as efficient contrast agents, with specific targeting abilities for broadband multimodal imaging that are usable for diagnostic applications and that extend into use as therapeutic agents as well.

  6. Efficient, stable, tunable, and easy to synthesize, handle and recycle luminescent materials: [H2NMe2]3[Ln(III)(2,6-dipicolinolate)3] (Ln = Eu, Tb, or its solid solutions).

    Science.gov (United States)

    Mooibroek, Tiddo Jonathan; Gamez, Patrick; Pevec, Andrej; Kasunic, Marta; Kozlevcar, Bojan; Fu, Wen-Tian; Reedijk, Jan

    2010-07-28

    Three compounds with the general formulae [H(2)N(Me)(2)](3)[Ln(2,6-dpa)(3)] were prepared from cheap and readily available reactants. Microcrystalline compounds could be isolated in high yields (>80%) by a simple filtration, after only one hour reaction time in refluxing DMF. The Eu and Tb compounds have been structurally characterized by single crystal X-ray diffraction. The compounds have unusual high-absorption coefficients (>95%) and quantum efficiencies (approximately 70%). Furthermore, they are thermally stable up to 250 degrees C and appear to be UV and water tolerant. The emission colour of the final compound can be easily fine-tuned, by varying the Eu:Tb ratio during the preparation.

  7. On-the-fly decoding luminescence lifetimes in the microsecond region for lanthanide-encoded suspension arrays

    Science.gov (United States)

    Lu, Yiqing; Lu, Jie; Zhao, Jiangbo; Cusido, Janet; Raymo, Françisco M.; Yuan, Jingli; Yang, Sean; Leif, Robert C.; Huo, Yujing; Piper, James A.; Paul Robinson, J.; Goldys, Ewa M.; Jin, Dayong

    2014-05-01

    Significant multiplexing capacity of optical time-domain coding has been recently demonstrated by tuning luminescence lifetimes of the upconversion nanoparticles called ‘τ-Dots’. It provides a large dynamic range of lifetimes from microseconds to milliseconds, which allows creating large libraries of nanotags/microcarriers. However, a robust approach is required to rapidly and accurately measure the luminescence lifetimes from the relatively slow-decaying signals. Here we show a fast algorithm suitable for the microsecond region with precision closely approaching the theoretical limit and compatible with the rapid scanning cytometry technique. We exploit this approach to further extend optical time-domain multiplexing to the downconversion luminescence, using luminescence microspheres wherein lifetimes are tuned through luminescence resonance energy transfer. We demonstrate real-time discrimination of these microspheres in the rapid scanning cytometry, and apply them to the multiplexed probing of pathogen DNA strands. Our results indicate that tunable luminescence lifetimes have considerable potential in high-throughput analytical sciences.

  8. Stable kilo-hertz electro-optically Q-switched Tm,Ho:YAP laser at room temperature

    Science.gov (United States)

    Liu, C.; Zhao, S.; Li, Y.; Yang, K.; Li, M.; Li, G.; Li, D.; Li, T.; Qiao, W.; Feng, T.; Chen, X.; Zheng, L.; Su, L.; Xu, J.

    2016-07-01

    A diode-pumped Tm,Ho:YAP laser utilizing a self-made LiNbO3 (LN) electro-optically modulator (EOM) at room temperature is demonstrated for the first time. A minimum pulse duration of 107.4 ns was obtained at a pulse repetition rate (PRR) of 200 Hz, giving a maximum single pulse energy of 1.65 mJ. At a PRR of 1 kHz, pulse duration of 145.8 ns was achieved under the absorbed pump power of 7.4 W, corresponding to a maximum single pulse energy of 0.546 mJ, and the pulse to pulse amplitude instabilities were measured to be about 4.6% and 5.83% for PRRs of 200 Hz and 1 kHz, respectively.

  9. Phase-sensitive optical coherence tomography-based vibrometry using a highly phase-stable akinetic swept laser source

    Energy Technology Data Exchange (ETDEWEB)

    Applegate, Brian E.; Park, Jesung; Carbajal, Esteban [Department of Biomedical Engineering, Texas A& M University, College Station, Texas (United States); Oghalai, John S. [Department of Otolaryngology - Head and Neck Surgery, Stanford University, Stanford, California (United States)

    2015-12-31

    Phase-sensitive Optical Coherence Tomography (PhOCT) is an emerging tool for in vivo investigation of the vibratory function of the intact middle and inner ear. PhOCT is able to resolve micron scale tissue morphology in three dimensions as well as measure picometer scale motion at each spatial position. Most PhOCT systems to date have relied upon the phase stability offered by spectrometer detection. On the other hand swept laser source based PhOCT offers a number of advantages including balanced detection, long imaging depths, and high imaging speeds. Unfortunately the inherent phase instability of traditional swept laser sources has necessitated complex user developed hardware/software solutions to restore phase sensitivity. Here we present recent results using a prototype swept laser that overcomes these issues. The akinetic swept laser is electronically tuned and precisely controls sweeps without any mechanical movement, which results in high phase stability. We have developed an optical fiber based PhOCT system around the akinetic laser source that had a 1550 nm center wavelength and a sweep rate of 140 kHz. The stability of the system was measured to be 4.4 pm with a calibrated reflector, thus demonstrating near shot noise limited performance. Using this PhOCT system, we have acquired structural and vibratory measurements of the middle ear in a mouse model, post mortem. The quality of the results suggest that the akinetic laser source is a superior laser source for PhOCT with many advantages that greatly reduces the required complexity of the imaging system.

  10. Zero-reabsorption doped-nanocrystal luminescent solar concentrators.

    Science.gov (United States)

    Erickson, Christian S; Bradshaw, Liam R; McDowall, Stephen; Gilbertson, John D; Gamelin, Daniel R; Patrick, David L

    2014-04-22

    Optical concentration can lower the cost of solar energy conversion by reducing photovoltaic cell area and increasing photovoltaic efficiency. Luminescent solar concentrators offer an attractive approach to combined spectral and spatial concentration of both specular and diffuse light without tracking, but they have been plagued by luminophore self-absorption losses when employed on practical size scales. Here, we introduce doped semiconductor nanocrystals as a new class of phosphors for use in luminescent solar concentrators. In proof-of-concept experiments, visibly transparent, ultraviolet-selective luminescent solar concentrators have been prepared using colloidal Mn(2+)-doped ZnSe nanocrystals that show no luminescence reabsorption. Optical quantum efficiencies of 37% are measured, yielding a maximum projected energy concentration of ∼6× and flux gain for a-Si photovoltaics of 15.6 in the large-area limit, for the first time bounded not by luminophore self-absorption but by the transparency of the waveguide itself. Future directions in the use of colloidal doped nanocrystals as robust, processable spectrum-shifting phosphors for luminescent solar concentration on the large scales required for practical application of this technology are discussed.

  11. Time-resolved luminescence from feldspars: New insight into fading

    DEFF Research Database (Denmark)

    Tsukamoto, S.; Denby, P.M.; Murray, A.S.

    2006-01-01

    Time-resolved infrared optically stimulated luminescence (IR-OSL) signals of K- and Na-feldspar samples extracted from sediments were measured in UV, blue and red detection windows, using a fast photon counter and pulsed IR stimulation (lambda = 875 nm). We observe that the relative contribution...

  12. Room-temperature wide-range luminescence and structural, optical, and electrical properties of SILAR deposited Cu-Zn-S nano-structured thin films

    Science.gov (United States)

    Jose, Edwin; Kumar, M. C. Santhosh

    2016-09-01

    We report the deposition of nanostructured Cu-Zn-S composite thin films by Successive Ionic Layer Adsorption and Reaction (SILAR) method on glass substrates at room temperature. The structural, morphological, optical, photoluminescence and electrical properties of Cu-Zn-S thin films are investigated. The results of X-ray diffraction (XRD) and Raman spectroscopy studies indicate that the films exhibit a ternary Cu-Zn-S structure rather than the Cu xS and ZnS binary composite. Scanning electron microscope (SEM) studies show that the Cu-Zn-S films are covered well over glass substrates. The optical band gap energies of the Cu-Zn-S films are calculated using UV-visible absorption measurements, which are found in the range of 2.2 to 2.32 eV. The room temperature photoluminescence studies show a wide range of emissions from 410 nm to 565 nm. These emissions are mainly due to defects and vacancies in the composite system. The electrical studies using Hall effect measurements show that the Cu-Zn-S films are having p-type conductivity.

  13. A promising RVO4:Eu(3+), Li(+)@SiO2 (R = Gd, Y and Gd/Y) red-emitting phosphor with improved luminescence (cd/m(2)) and colour purity for optical display applications.

    Science.gov (United States)

    Rambabu, Urlagaddala; Munirathnam, Nagegownivari Ramachandra; Reddy, Busireddy Sudhakar; Chatterjee, Sandip

    2016-02-01

    Red emission intensity was optimized in three stages, by investigating the effects of: (i) host composition (Gd, Y and Gd/Y), (ii) codoping Li(+) as a sensitizer and, finally, (iii) with a SiO2 shell coating as a protecting layer. Lanthanide vanadate powder phosphors were synthesized using a modified colloidal precipitation technique. The effects of SiO2 coating on phosphor particles were characterized using scanning electron microscopy (SEM)-EDAX, transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and photoluminescence (PL) measurements. An improvement in the PL intensity on Li codoping was due to improved crystallinity, which led to higher oscillating strengths for the optical transitions, and also a lowering of the inversion symmetry of Eu(3+) ions. Red emission intensity due to (5)D0  → (5)D2 transition of the phosphor Y0.94VO4:Eu(3+)0.05, Li(+)0.01 was enhanced by 22.28% compared with Y0.95VO4:Eu(3+)0.05, and was further improved by 58.73% with SiO2 coating. The luminescence intensity (I) and colour coordinates (x, y) of the optimized phosphor Y0.94VO4:Eu(3+)0.05, Li(+)0.01@SiO2, where I = 13.07 cd/m(2) and (x = 0.6721, y = 0.3240), were compared with values for a commercial red phosphor (Y2O2S:Eu(3+)), where I = 27 cd/m(2) and (x = 0.6522, y = 0.3437). The measured colour coordinates are superior to those of the commercial red phosphor, and moreover, match well with standard NTSC values (x = 0.67, y = 0.33). Copyright © 2015 John Wiley & Sons, Ltd.

  14. Optically stimulated luminescence response to ionizing radiation of red bricks (SiO{sub 2}, Al{sub 2}O{sub 3} an Fe{sub 2}O{sub 3}) used as building materials

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, G.; Golzarri, J. I.; Santiago, P. [Instituto de Fisica, UNAM, Apartado Postal 20-364, 01000 Mexico D. F. (Mexico); Bogard, J. S. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge TN 37831-6426 (United States)]. e-mail: espinosa@fisica.unam.mx

    2008-02-15

    Quartz is the most common mineral in our environment. It is found in granite, hydrothermal veins and volcanic rocks, as well as in sedimentary deposits derived from such solid materials. These sediments are also made into building materials, such as bricks and pottery. Thus the potential use of a dose reconstruction technique based on quartz grains is enormous, whether as a dating tool in archaeology and quaternary geology, or in nuclear accident dosimetry. This work describes the Optically Stimulated Luminescence (OSL) response of red brick to ionizing radiation. The bricks, from the state of Puebla, Mexico, represent another class of materials that can be used in retrospective dosimetry following nuclear or radiological incidents. The chemical composition of fifteen bricks (three samples from five different brick factories) was determined, using energy dispersive spectroscopy, be primarily SiO{sub 2}, Al{sub 2}0{sub 3} and Fe{sub 2}O{sub 3} and is believed to be representative for this common building material. Individual aliquots from these bricks were powdered in agate mortars and thermally annealed. Replicate samples of the aliquots were then irradiated with beta particles from a sealed source of {sup 9}0Sr/{sup 9}0Y. The OSL response was measured with a Daybreak Model 2200 High-Capacity OSL Reader System. We present here for this material the characteristic OSL response to beta particles; the reproducibility of the OSL response; the linearity of the response in the dose range 0.47 Gy to 47 Gy; and the fading characteristics. (Author)

  15. Luminescent properties of aluminum hydride

    Energy Technology Data Exchange (ETDEWEB)

    Baraban, A.P.; Gabis, I.E.; Dmitriev, V.A. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Dobrotvorskii, M.A., E-mail: mstislavd@gmail.com [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Kuznetsov, V.G. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Matveeva, O.P. [National Mineral Resources University, Saint Petersburg 199106 (Russian Federation); Titov, S.A. [Petersburg State University of Railway Transport, Saint-Petersburg 190031 (Russian Federation); Voyt, A.P.; Elets, D.I. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation)

    2015-10-15

    We studied cathodoluminescence and photoluminescence of α-AlH{sub 3}– a likely candidate for use as possible hydrogen carrier in hydrogen-fueled vehicles. Luminescence properties of original α-AlH{sub 3} and α-AlH{sub 3} irradiated with ultraviolet were compared. The latter procedure leads to activation of thermal decomposition of α-AlH{sub 3} and thus has a practical implementation. We showed that the original and UV-modified aluminum hydride contain luminescence centers ‐ structural defects of the same type, presumably hydrogen vacancies, characterized by a single set of characteristic bands of radiation. The observed luminescence is the result of radiative intracenter relaxation of the luminescence center (hydrogen vacancy) excited by electrons or photons, and its intensity is defined by the concentration of vacancies, and the area of their possible excitation. UV-activation of the dehydrogenation process of aluminum hydride leads to changes in the spatial distribution of the luminescence centers. For short times of exposure their concentration increases mainly in the surface regions of the crystals. At high exposures, this process extends to the bulk of the aluminum hydride and ends with a decrease in concentration of luminescence centers in the surface region. - Highlights: • Aluminum hydride contains hydrogen vacancies which serve as luminescence centers. • The luminescence is the result of radiative relaxation of excited centers. • Hydride UV-irradiation alters distribution and concentration of luminescence centers.

  16. Investigation on structural, thermal, optical and sensing properties of meta-stable hexagonal MoO3 nanocrystals of one dimensional structure

    Directory of Open Access Journals (Sweden)

    Angamuthuraj Chithambararaj

    2011-09-01

    Full Text Available Hexagonal molybdenum oxide (h-MoO3 was synthesized by a solution based chemical precipitation technique. Analysis by X-ray diffraction (XRD confirmed that the as-synthesized powder had a metastable hexagonal structure. The characteristic vibrational band of Mo–O was identified from Fourier transform infrared spectroscopy (FT-IR. Scanning electron microscopy (SEM and transmission electron microscopy (TEM images clearly depicted the morphology and size of h-MoO3. The morphology study showed that the product comprises one-dimensional (1D hexagonal rods. From the electron energy loss spectroscopy (EELS measurement, the elemental composition was investigated and confirmed from the characteristic peaks of molybdenum and oxygen. Thermogravimetric (TG analysis on metastable MoO3 revealed that the hexagonal phase was stable up to 430 °C and above this temperature complete transformation into a highly stable orthorhombic phase was achieved. The optical band gap energy was estimated from the Kubelka–Munk (K–M function and was found to be 2.99 eV. Finally, the ethanol vapor-sensing behavior was investigated and the sensing response was found to vary linearly as a function of ethanol concentration in the parts per million (ppm range.

  17. Activatable Multifunctional Persistent Luminescence Nanoparticle/Copper Sulfide Nanoprobe for in Vivo Luminescence Imaging-Guided Photothermal Therapy.

    Science.gov (United States)

    Chen, Li-Jian; Sun, Shao-Kai; Wang, Yong; Yang, Cheng-Xiong; Wu, Shu-Qi; Yan, Xiu-Ping

    2016-12-07

    Multifunctional nanoprobes that provide diagnosis and treatment features have attracted great interest in precision medicine. Near-infrared (NIR) persistent luminescence nanoparticles (PLNPs) are optimal materials due to no in situ excitation needed, deep tissue penetration, and high signal-to-noise ratio, while activatable optical probes can further enhance signal-to-noise ratio for the signal turn-on nature. Here, we show the design of an activatable multifunctional PLNP/copper sulfide (CuS)-based nanoprobe for luminescence imaging-guided photothermal therapy in vivo. Matrix metalloproteinases (MMPs)-specific peptide substrate (H2N-GPLGVRGC-SH) was used to connect PLNP and CuS to build a MMP activatable system. The nanoprobe not only possesses ultralow-background for in vivo luminescence imaging due to the absence of autofluorescence and optical activatable nature but also offers effective photothermal therapy from CuS nanoparticles. Further bioconjugation of c(RGDyK) enables the nanoprobe for cancer-targeted luminescence imaging-guided photothermal therapy. The good biocompatibility and the multiple functions of highly sensitive tumor-targeting luminescence imaging and effective photothermal therapy make the nanoprobe promising for theranostic application.

  18. Luminescence and Luminescence Quenching in Gd3(Ga,Al)5O12 Scintillators Doped with Ce3+

    NARCIS (Netherlands)

    Ogiegło, J.M.; Katelnikovas, A.; Zych, A.K.|info:eu-repo/dai/nl/31407564X; Jüstel, T.; Meijerink, A.|info:eu-repo/dai/nl/075044986; Ronda, R.C.

    2013-01-01

    The optical properties of gadolinium gallium aluminum garnet, Gd3(Ga,Al)5O12, doped with Ce3+ are investigated as a function of the Ga/Al ratio, aimed at an improved understanding of the energy flow and luminescence quenching in these materials. A decrease of both the crystal field strength and band

  19. Luminescence and Luminescence Quenching in Gd3(Ga,Al)5O12 Scintillators Doped with Ce3+

    NARCIS (Netherlands)

    Ogiegło, J.M.; Katelnikovas, A.; Zych, A.K.; Jüstel, T.; Meijerink, A.; Ronda, R.C.

    2013-01-01

    The optical properties of gadolinium gallium aluminum garnet, Gd3(Ga,Al)5O12, doped with Ce3+ are investigated as a function of the Ga/Al ratio, aimed at an improved understanding of the energy flow and luminescence quenching in these materials. A decrease of both the crystal field strength and band

  20. Optical diffraction tomography using a digital micromirror device for stable measurements of 4D refractive index tomography of cells

    Science.gov (United States)

    Shin, Seungwoo; Kim, Kyoohyun; Kim, Taeho; Yoon, Jonghee; Hong, Kihyun; Park, Jinah; Park, YongKeun

    2016-03-01

    Optical diffraction tomography (ODT) is an interferometric microscopy technique capable of measuring 3-D refractive index (RI) distribution of transparent samples. Multiple 2-D holograms of a sample illuminated with various angles are measured, from which 3-D RI map of the sample is reconstructed via the diffraction theory. ODT has been proved as a powerful tool for the study of biological cells, due to its non-invasiveness, label-free and quantitative imaging capability. Recently, our group has demonstrated that a digital micromirror device (DMD) can be exploited for fast and precise control of illumination beams for ODT. In this work, we systematically study the precision and stability of the ODT system equipped with a DMD and present measurements of 3-D and 4-D RI maps of various types of live cells including human red blood cells, white blood cells, hepatocytes, and HeLa cells. Furthermore, we also demonstrate the effective visualization of 3-D RI maps of live cells utilizing the measured information about the values and gradient of RI tomograms.

  1. Optical diffraction tomography using a digital micromirror device for stable measurements of 4-D refractive index tomography of cells

    CERN Document Server

    Shin, Seungwoo; Kim, Taeho; Yoon, Jonghee; Hong, Kihyun; Park, Jinah; Park, YongKeun

    2016-01-01

    Optical diffraction tomography (ODT) is an interferometric microscopy technique capable of measuring 3-D refractive index (RI) distribution of transparent samples. Multiple 2-D holograms of a sample illuminated with various angles are measured, from which 3-D RI map of the sample is reconstructed via the diffraction theory. ODT has been proved as a powerful tool for the study of biological cells, due to its non-invasiveness, label-free and quantitative imaging capability. Recently, our group has demonstrated that a digital micromirror device (DMD) can be exploited for fast and precise control of illumination beams for ODT. In this work, we systematically study the precision and stability of the ODT system equipped with a DMD and present measurements of 3-D and 4-D RI maps of various types of live cells including human red blood cells, white blood cells, hepatocytes, and HeLa cells. Furthermore, we also demonstrate the effective visualization of 3-D RI maps of live cells utilizing the measured information abou...

  2. Stable dual-wavelength single-longitudinal-mode ring erbium-doped fiber laser for optical generation of microwave frequency

    Science.gov (United States)

    Wang, T.; Liang, G.; Miao, X.; Zhou, X.; Li, Q.

    2012-05-01

    We demonstrate a simple dual-wavelength ring erbium-doped fiber laser operating in single-longitudinal-mode (SLM) at room temperature. A pair of reflection type short-period fiber Bragg gratings (FBGs), which have two different center wavelengths of 1545.072 and 1545.284 nm, are used as the wavelength-selective component of the laser. A segment of unpumped polarization maintaining erbium-doped fiber (PM-EDF) is acted as a narrow multiband filter. By turning the polarization controller (PC) to enhance the polarization hole burning (PHB), the single-wavelength and dual-wavelength laser oscillations are observed at 1545.072 and 1545.284 nm. The output power variation is less than 0.6 dB for both wavelengths over a five-minute period and the optical signal to noise ratio (OSNR) is greater than 50 dB. By beating the dual-wavelengths at a photodetector (PD), a microwave signal at 26.44 GHz is demonstrated.

  3. Influence of Inert and Oxidizing Atmospheres on the Physical and Optical Properties of Luminescent Carbon Dots Prepared through Pyrolysis of a Model Molecule.

    Science.gov (United States)

    Machado, Cláudia Emanuele; Tartuci, Letícia Gazola; de Fátima Gorgulho, Honória; de Oliveira, Luiz Fernando Cappa; Bettini, Jefferson; Pereira dos Santos, Daniela; Ferrari, Jefferson Luis; Schiavon, Marco Antônio

    2016-03-18

    This work used L-tartaric acid as a model molecule to evaluate how the use of inert and oxidizing atmospheres during pyrolysis affected the physical and optical properties of the resulting carbon dots (CDs). Pyrolysis revealed to be a simple procedure that afforded CDs in a single step, dismissed the addition of organic solvents, and involved only one extraction stage that employed water. By X-ray diffraction a dependency between the structure of the CDs and the atmosphere (oxidizing or inert) used during the pyrolysis was found. Potentiometric titration demonstrated that the CDs were largely soluble in water; it also aided characterization of the various groups that contained sp(3) -hybridized carbon atoms on the surface of the dots. Raman spectroscopy suggested that different amounts of sp(2)- and sp(3)-hybridized carbon atoms emerged on the CDs depending on the pyrolysis atmosphere. In conclusion, the pyrolysis atmosphere influenced the physical properties, such as the composition and the final structure.

  4. New luminescent materials and filters for Luminescent Solar Concentrators

    NARCIS (Netherlands)

    De Boer, D.K.G.; Ronda, C.R.; Keur, W.C.; Meijerink, A.

    2012-01-01

    In a Luminescent Solar Concentrator (LSC), short-wavelength light isconverted by a luminescent material into long-wavelength light, which is guided towards a photovoltaic cell. In principle, an LSC allows for high concentration, but in practice this is prevented by lossmechanisms like limited sunlig

  5. Nanoscale luminescent lanthanide-based metal–organic frameworks: properties, synthesis, and applications

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Dongqin; Song, Yonghai; Wang, Li, E-mail: lwanggroup@aliyun.com [Jiangxi Normal University, Key Laboratory of Functional Small Organic Molecule, Ministry of Education, Key Laboratory of Chemical Biology, Jiangxi Province, College of Chemistry and Chemical Engineering (China)

    2015-07-15

    Nanoscale luminescent lanthanide-based metal–organic frameworks (NLLn-MOFs) possess superior optical and physical properties such as higher luminescent lifetime, quantum yield, high stability, high surface area, high agent loading, and intrinsic biodegradability, and therefore are regarded as a novel generation of luminescent material compared with bulk lanthanide-based metal–organic frameworks (Ln-MOFs). Traditional luminescent Ln-MOFs have been well studied; however, NLLn-MOFs taking the advantages of nanomaterials have attracted extensive investigations for applications in optical imaging in living cells, light-harvesting, and sensing. In this review, we provide a survey of the latest progresses made in developing NLLn-MOFs, which contains the fundamental optical features, synthesis, and their potential applications. Finally, the future prospects and challenges of the rapidly growing field are summarized.

  6. Luminescent properties of diamond single crystals of pyramidal shape

    Science.gov (United States)

    Alekseev, A. M.; Tuyakova, F. T.; Obraztsova, E. A.; Korostylev, E. V.; Klinov, D. V.; Prusakov, K. A.; Malykhin, S. A.; Ismagilov, R. R.; Obraztsov, A. N.

    2016-11-01

    The luminescence properties of needle-like crystals of diamond, obtained by selective oxidation of textured polycrystalline diamond films, are studied. Diamond films were grown by chemical vapor deposition from a methane-hydrogen mixture activated by a DC discharge. The spectra of photo- and cathodoluminescence and the spatial distribution of the intensity of radiation at different wavelengths are obtained for individual needle-like crystals. Based on the spectral characteristics, conclusions are made about the presence of optically active defects containing nitrogen and silicon impurities in their structure, as well as the significant effect of structural defects on their luminescence spectra.

  7. Physico-chemical characterizations of Cr doped persistent luminescence nanoparticles

    Science.gov (United States)

    Lecuyer, T.; Teston, E.; Maldiney, T.; Scherman, D.; Richard, C.

    2016-03-01

    Persistent luminescence nanoparticles have recently been proposed as innovative optical probes for small animal in vivo imaging. The main advantage of such probes is their ability to emit light for a long time after the end of their excitation, allowing in vivo imaging with low background. This work reports new information on the physico-chemical characterizations of Cr doped ZnGa2O4 nanoprobes in terms of synthetic procedure, luminescence properties as well as colloidal stabilities in different aqueous media and over the time.

  8. Method for simultaneous luminescence sensing of two species using optical probes of different decay time, and its application to an enzymatic reaction at varying temperature.

    Science.gov (United States)

    Nagl, Stefan; Stich, Matthias I J; Schäferling, Michael; Wolfbeis, Otto S

    2009-02-01

    Chemical sensing, imaging and microscopy based on the use of fluorescent probes has so far been limited almost exclusively to the detection of a single parameter at a time. We present a scheme that can overcome this limitation by enabling optical sensing of two parameter simultaneously and even at identical excitation and emission wavelengths of two probes provided (a) their decay times are different enough to enable two time windows to be recorded, and (b) the emission of the shorter-lived probe decays to below the detectable limit while that of the other still can be measured. We refer to this new scheme as the dual lifetime determination (DLD) method and show that it can be widely varied by appropriate choice of probes and experimental settings. DLD is demonstrated to work by sensing oxygen and temperature independently from each other by making use of two probes, one for oxygen (a platinum porphyrin dissolved in polystyrene), and one for temperature [a europium complex dissolved in poly(vinyl methylketone)]. DLD was applied to monitor the consumption of oxygen in the glucose oxidase-catalyzed oxidation of glucose at varying temperatures. The scheme is expected to have further applications in cellular assays and biophysical imaging.

  9. A novel orange emitting Sm3+ ions doped NaCaAlPO4F3 phosphor: Optical and luminescence properties

    Science.gov (United States)

    Nagaraja, R.; Pushpa Manjari, V.; Sailaja, B.; Ravikumar, R. V. S. S. N.

    2017-02-01

    A novel orange light emitting Sm3+ ions doped NaCaAlPO4F3 phosphor was synthesized via solid state reaction. The prepared sample was characterized by powder X-ray diffraction (PXRD), Optical absorption, Photoluminescence (PL) and Fourier Transform Infrared Spectroscopy (FT-IR) techniques. From powder XRD data, the average crystallite size and structural parameters are estimated. Absorption spectra consist of ten absorption peaks corresponding to the transitions from the 6H5/2 ground state to various excited energy levels. Transition probabilities, branching ratios and radiative lifetime were evaluated by using Judd-Ofelt analysis. Photoluminescence spectrum show three prominent emission bands centered at 562, 597 and 643 nm corresponding to the 4G5/2 → 6HJ (J = 5/2, 7/2 and 9/2) transitions respectively. From the emission transitions, stimulated emission cross-section (σe) and gain bandwidth (GBW) were predicted. The decay profiles of the prepared phosphor reveals the single exponential nature and the experimental lifetime is calculated. The colorimetric parameters CIE coordinates, Correlated color temperature of the prepared phosphor are also evaluated. FT-IR spectrum demonstrates the characteristic vibration bands of the prepared phosphor material.

  10. Intense white light luminescent Dy3+ doped lithium borate glasses for W-LED: A correlation between physical, thermal, structural and optical properties

    Science.gov (United States)

    Pawar, P. P.; Munishwar, S. R.; Gedam, R. S.

    2017-02-01

    In this article the physical, thermal structural and optical properties of Dy3+ doped lithium borate glasses have been studied for white LED application. The emission spectra shows two intense emission bands at around 483 nm and 574 nm corresponds to the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions along with one feeble band at 663 nm corresponds to 4F9/2 → 6H11/2 transition. The average lifetime of Dy3+ were found to be about 2.95 and 4.94 ns for blue and yellow emission bands respectively. CIE chromaticity diagram shows glass LBD-4 containing 0.5 mol% Dy2O3 with colour co-ordinates x = 0.33 and y = 0.37 have highest emission intensity. These glasses having emission in the white region and thus can be used for bright white LED's and modern white LED bulbs.

  11. Optical pressure and temperature sensor based on the luminescence properties of Nd3+ ion in a gadolinium scandium gallium garnet crystal.

    Science.gov (United States)

    León-Luis, S F; Muñoz-Santiuste, J E; Lavín, V; Rodríguez-Mendoza, U R

    2012-04-23

    Hypersensitivity to pressure and temperature is observed in the near-infrared emission lines of the Nd(3+) ion in a Cr(3+),Nd(3+):Gd(3)Sc(2)Ga(3)O(12) crystal, associated to the R(1,2)((4)F(3/2))→Z(5)((4)I(9/2)) and R(1,2)((4)F(3/2))→Z(1)((4)I(9/2)) transitions. The former emissions show large linear pressure coefficients of -11.3 cm(-1)/GPa and -8.8 cm(-1)/GPa, while the latter show high thermal sensitivity in the low temperature range. Thus this garnet crystal can be considered a potential optical pressure and/or temperature sensor in high pressure and temperature experiments up to 12 GPa and below room temperature, used in diamond anvil cells and excited with different UV and visible commercial laser due to the multiple Cr(3+) and Nd(3+) absorption bands.

  12. Silicon quantum dots for optical applications

    Science.gov (United States)

    Wu, Jeslin J.

    Luminescent silicon quantum dots (SiQDs) are emerging as attractive materials for optoelectronic devices, third generation photovoltaics, and bioimaging. Their applicability in the real world is contingent on their optical properties and long-term environmental stability; and in biological applications, factors such as water solubility and toxicity must also be taken into consideration. The aforementioned properties are highly dependent on the QDs' surface chemistry. In this work, SiQDs were engineered for the respective applications using liquid-phase and gas-phase functionalization techniques. Preliminary work in luminescent downshifting for photovoltaic systems are also reported. Highly luminescent SiQDs were fabricated by grafting unsaturated hydrocarbons onto the surface of hydrogen-terminated SiQDs via thermal and photochemical hydrosilylation. An industrially attractive, all gas-phase, nonthermal plasma synthesis, passivation (aided by photochemical reactions), and deposition process was also developed to reduce solvent waste. With photoluminescence quantum yields (PLQYs) nearing 60 %, the alkyl-terminated QDs are attractive materials for optical applications. The functionalized SiQDs also exhibited enhanced thermal stability as compared to their unfunctionalized counterparts, and the photochemically-hydrosilylated QDs further displayed photostability under UV irradiation. These environmentally-stable SiQDs were used as luminescent downshifting layers in photovoltaic systems, which led to enhancements in the blue photoresponse of heterojunction solar cells. Furthermore, the QD films demonstrated antireflective properties, improving the coupling efficiency of sunlight into the cell. For biological applications, oxide, amine, or hydroxyl groups were grafted onto the surface to create water-soluble SiQDs. Luminescent, water-soluble SiQDs were produced in by microplasma treating the QDs in water. Stable QYs exceeding 50 % were obtained. Radical-based and

  13. Luminescence dating of Netherland's sediments

    NARCIS (Netherlands)

    Wallinga, J.; Davids, F.; Dijkmans, J.W.A.

    2007-01-01

    Over the last decades luminescence dating techniques have been developed that allow earth scientists to determine the time of deposition of sediments. In this contribution we revity: 1) the development of the methodology, 2) tests of the reliability of luminescence dating on Netherlands' sediments;

  14. Power dependence of upconversion luminescence

    NARCIS (Netherlands)

    Pollnau, Markus; Güdel, H.U.

    Spectroscopic data are of essential value for understanding the excitation mechanisms in luminescent and laser materials. Special attention has been devoted to the investigation of upconversion-induced luminescence, partly because of the availability of near-infrared pump sources for the excitation

  15. Lanthanide-doped luminescent nanomaterials. From fundamentals to bioapplications

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xueyuan; Tu, Datao; Liu, Yongsheng [Chinese Academy of Sciences, Fuzhou (China). Fujian Inst. of Research on the Structure of Matter

    2014-07-01

    Covers the frontiers in chemistry, physics and bioapplications of lanthanide-doped luminescent nanomaterials. Presents new insights into the optical behaviors of lanthanide in nanomaterials. Systematically reviews in-vitro biodetection and bioimaging based on lanthanide-doped inorganic nanocrystals. Lanthanide-Doped Luminescent Nanomaterials reviews the latest advances in the development of lanthanide-doped luminescent inorganic nanoparticles for potential bioapplications. This book covers the chemical and physical fundamentals of these nanoparticles, such as the controlled synthesis methodology, surface modification chemistry, optical physics, and their promising applications in diverse bioassays, with an emphasis on heterogeneous and homogeneous in-vitro biodetection of tumor biomarkers. This book is intended for those readers who are interested in systematically understanding the materials design strategy, optical behavior of lanthanide ions, and practical bioapplications of lanthanide nanoparticles. It primarily focuses on the interdisciplinary frontiers in chemistry, physics and biological aspects of luminescent nanomaterials. All chapters were written by scientists active in this field and for a broad audience, providing both beginners and advanced researchers with comprehensive information on the subject.

  16. NIR luminescence studies on Er{sup 3+}:Yb{sup 3+} co-doped sodium telluroborate glasses for lasers and optical amplifer applications

    Energy Technology Data Exchange (ETDEWEB)

    Annapoorani, K.; Marimuthu, K., E-mail: mari-ram2000@yahoo.com [Department of Physics, Gandhigram Rural Institute - Deemed University, Gandhigram – 624 302 (India); Murthy, N. Suriya [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam–603 102 (India)

    2016-05-23

    Er{sup 3+}:Yb{sup 3+} co-doped Sodium telluroborate glasses were prepared with the chemical composition (49.5–x)B{sub 2}O{sub 3}+25TeO{sub 2}+5Li{sub 2}CO{sub 3}+10ZnO+10NaF+0.5Er{sub 2}O{sub 3}+xYb{sub 2}O{sub 3} (where x= 0.1, 0.5, 1.0 and 2.0 in mol %) following the melt quenching technique. With the addition of Yb{sup 3+} ions into Er{sup 3+} ions in the prepared glasses, the absorption cross-section values were found to increase due to the effective energy transfer from {sup 2}F{sub 5/2} level of Yb{sup 3+} ions to the {sup 4}I{sub 11/2} level of Er{sup 3+} ions. The fluorescence around 1550 nm correspond to the {sup 4}I{sub 13/2}→{sup 4}I{sub 15/2} transition was observed under 980 nm pumping. Among the present glasses, integrated intensity was found to be higher for 1.0 mol% Yb{sup 3+} ion glass. The parameters such as stimulated emission cross- section, Gain bandwidth and quantum efficiency of the {sup 4}I{sub 13/2}→{sup 4}I{sub 15/2} transition was found to be higher for the NTBE1.0Y glass and the same is suggested for potential NIR lasers and optical amplifier applications.

  17. Fabrication and properties of luminescence polymer composites with erbium/ytterbium oxides and gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Julia A. Burunkova

    2016-04-01

    Full Text Available Rare-earth-doped optical materials are important for light sources in optoelectronics, as well as for efficient optical amplification elements and other elements of photonics. On the basis of the previously developed method of anhydrous, low-temperature synthesis of Er/Yb oxides from their chlorides we fabricated proper nanoparticles with defined parameters and used them for the development of optically transparent, luminescent polymer nanocomposite with low optical scattering, suitable for direct, light-induced formation of photonic elements. Introduction of preformed gold nanoparticles in such a nanocomposite was also performed and an enhancement of luminescence due to the influence of plasmon effects was detected.

  18. Polarization and spectral characteristics of the two-photon luminescence from colloidal gold nanoparticles excited by tunable laser radiation

    Energy Technology Data Exchange (ETDEWEB)

    Yashunin, D. A., E-mail: yashuninda@yandex.ru; Korytin, A. I.; Stepanov, A. N. [Russian Academy of Sciences, Institute of Applied Physics (Russian Federation)

    2015-12-15

    We have experimentally studied two-photon luminescence from a colloidal solution of spherical gold nanoparticles by tuning the wavelength of the exciting radiation. The measured polarization and spectral characteristics of the two-photon luminescence signal show that the observed nonlinear optical response is determined by the dimers present in the solution with a concentration of a few percent of total nanoparticle number.

  19. A luminescent nisin biosensor

    Science.gov (United States)

    Immonen, Nina; Karp, Matti

    2006-02-01

    Nisin is a lantibiotic, an antibacterial peptide produced by certain Lactococcus lactis strains that kills or inhibits the growth of other bacteria. Nisin is widely used as a food preservative, and its long-time use suggests that it can be generally regarded as safe. We have developed a method for determining the amount of nisin in food samples that is based on luminescent biosensor bacteria. Bacterial luciferase operon luxABCDE was inserted into plasmid pNZ8048, and the construct was transformed by electroporation into Lc. lactis strain NZ9800, whose ability to produce nisin has been erased by deletion of the gene nisA. The operon luxABCDE has been modified to be functional in gram-positive bacteria to confer a bioluminescent phenotype without the requirement of adding an exogenous substrate. In the plasmid pNZ8048, the operon was placed under control of the nisin-inducible nisA promoter. The chromosomal nisRK genes of Lc. lactis NZ9800 allow it to sense nisin in the environment and relay this signal via signal transduction proteins NisK and NisR to initiate transcription from nisA promoter. In the case of our sensor bacteria, this leads to production of luciferase and, thus, luminescence that can be directly measured from living bacteria. Luminescence can be detected as early as within minutes of induction. The nisin assay described here provides a detection limit in the sub-picogram level per ml, and a linear area between 1 - 1000 pg/ml. The sensitivity of this assay exceeds the performance of all previously published methods.

  20. Stimulated luminescence emission from localized recombination in randomly distributed defects

    DEFF Research Database (Denmark)

    Jain, Mayank; Guralnik, Benny; Andersen, Martin Thalbitzer

    2012-01-01

    We present a new kinetic model describing localized electronic recombination through the excited state of the donor (d) to an acceptor (a) centre in luminescent materials. In contrast to the existing models based on the localized transition model (LTM) of Halperin and Braner (1960 Phys. Rev. 117...... that evolves only in the temporal domain. An excellent agreement is observed between thermally and optically stimulated luminescence (TL and OSL) results produced from the two models. In comparison to the first-order kinetic behaviour of the LTM of Halperin and Braner (1960 Phys. Rev. 117 408–15), our model...... results in a highly asymmetric TL peak; this peak can be understood to derive from a continuum of several first-order TL peaks. Our model also shows an extended power law behaviour for OSL (or prompt luminescence), which is expected from localized recombination mechanisms in materials with random...

  1. Electric Field Oriented Nanostructured Organic Thin Films with Polarized Luminescence.

    Science.gov (United States)

    Karbovnyk, I D; Olenych, I; Kukhta, I N; Lugovskii, A; Sasnouski, G; Chutora, T; Luchechko, A P; Khalakhan, I; Kukhta, A

    2017-12-01

    The effect of the external electric field of 10(5) V/m on the ordering of two luminescent liquid crystalline molecules (1-pentyl-2(/),3(/)-difluoro-3(///)-methyl-4(////)-octyl-p-quinguephenyl and 9,10-Bis (4-pentylphenylethynyl)antracene) during thermal vacuum deposition is studied. The morphology, electrical conductivity, optical absorption, luminescence spectra, and polarization are presented and analyzed. All data show the formation of ordered films. The polarization degree is 60% for 1-pentyl-2(/),3(/)-difluoro-3(///)-methyl-4(////)-octyl-p-quinguephenyl oriented films and 28% for 9,10-Bis (4-pentylphenylethynyl)antracene. The lower value of M2 luminescence polarization can be explained by the absence of dipole moment in this molecule.

  2. LUMINESCENCE OF CADMIUM SULFIDE QUANTUM DOTS IN FLUOROPHOSPHATE GLASSES

    Directory of Open Access Journals (Sweden)

    Z. O. Lipatova

    2015-03-01

    Full Text Available Cadmium sulfide quantum dots are perspective materials in optics, medicine, biology and optoelectronics. Fluorophosphate glasses, doped with cadmium sulfide quantum dots, were examined in the paper. Heat treatment led to the formation of quantum dots with diameters equal to 2.8 nm, 3.0 nm and 3.8 nm. In view of such changes in the quantum dots size the fundamental absorption edge shift and the luminescence band are being displaced to the long wavelengths. Luminescence lifetime has been found to be dependent on the registration wavelength in the range from 450 to 700 nm. Obtained fluorophosphate glasses with CdS quantum dots can find their application as fluorescent materials with intensive luminescence band and long excited-state natural lifetime.

  3. Nanophosphor aluminum oxide: Luminescence response of a potential dosimetric material

    Energy Technology Data Exchange (ETDEWEB)

    Blair, Michael W., E-mail: mblair@lanl.go [Los Alamos National Laboratory, Los Alamos, NM (United States); Jacobsohn, Luiz G. [Center for Optical Materials Science and Engineering Technologies, and the School of Materials Science and Engineering, Clemson University, Anderson, SC 29625 (United States); Tornga, Stephanie C. [Los Alamos National Laboratory, Los Alamos, NM (United States); Ugurlu, Ozan [Characterization Facility, Institute of Technology, University of Minnesota, Minneapolis, MN 55455 (United States); Bennett, Bryan L. [Los Alamos National Laboratory, Los Alamos, NM (United States); Yukihara, Eduardo G. [Department of Physics, Oklahoma State University, Stillwater, OK (United States); Muenchausen, Ross E. [Los Alamos National Laboratory, Los Alamos, NM (United States)

    2010-05-15

    This work reports on the investigation of the radiation dosimetry properties of Al{sub 2}O{sub 3} nanopowders. Samples were produced by solution combustion synthesis using three different organic fuels to check for the effect of synthesis conditions on the properties of interest. Luminescence characteristics were studied by thermoluminescence and optically stimulated luminescence (OSL) techniques. We found that samples produced using urea have characteristics similar to bulk Al{sub 2}O{sub 3}:C and may be suitable for personal dosimetry, while samples produced using glycine and hexamethylenetetramine (HMT) may be more suitable for applications where fast OSL decay is advantageous. While these results are promising and warrant further investigation, much has to be done to overcome the greatly decreased luminescence intensity of the nanomaterials as compared to bulk Al{sub 2}O{sub 3}:C.

  4. Luminescence from wide band gap materials and their applications

    Science.gov (United States)

    Shinde, S. L.; Senapati, S.; Nanda, K. K.

    2015-03-01

    We demonstrate ZnO and In2O3 microcrystals as an optical probe for wide range thermometry. Both ZnO and In2O3 microcrystals exhibit a monotonic decrease in luminescence intensities with increase in temperature. The variation has been explored to develop a thermometer in a wide temperature range. We also demonstrate enhanced brightness from broad-luminescent-wide band gap materials when sensitized with low band gap CdTe quantum dots. Wide band gap materials act as acceptors, while CdTe act as donors. One of the major implications is the designing of weak-luminescent-wide-band gap materials as bright white light emitting phosphors that can convert the ultraviolet into visible light. Invited talk at the 7th International Workshop on Advanced Materials Science and Nanotechnology IWAMSN2014, 2-6 November, 2014, Ha Long, Vietnam.

  5. Note: Near infrared spectral and transient measurements of PbS quantum dots luminescence

    Science.gov (United States)

    Parfenov, P. S.; Litvin, A. P.; Ushakova, E. V.; Fedorov, A. V.; Baranov, A. V.; Berwick, K.

    2013-11-01

    We describe an experimental setup for the characterization of luminescence from nanostructures. The setup is intended for steady-state and time-resolved luminescence measurements in the near-infrared region. The setup allows us to study spectral luminescence properties in the spectral range of 0.8-2.0 μm with high spectral resolution and kinetic luminescence properties between 0.8 and 1.7 μm with a time resolution of 3 ns. The capabilities of the system are illustrated by taking luminescence measurements from PbS quantum dots. We established the size dependencies of the optical properties of the PbS quantum dots over a wide spectral range. Finally, the energy transfer process was studied with a high temporal and spectral resolution.

  6. Stored Luminescence Computed Tomography

    CERN Document Server

    Cong, Wenxiang; Wang, Ge

    2013-01-01

    The phosphor nanoparticles made of doped semiconductors, pre-excited by well-collimated X-ray radiation, were recently reported for their light emission upon NIR light stimulation. The characteristics of X-ray energy storage and NIR stimulated emission is highly desirable to design targeting probes and improve molecular and cellular imaging. Here we propose stored luminescence computed tomography (SLCT), perform realistic numerical simulation, and demonstrate a much-improved spatial resolution in a preclinical research context. The future opportunities are also discussed along this direction.

  7. Luminescent macrocyclic lanthanide complexes

    Science.gov (United States)

    Raymond, Kenneth N [Berkeley, CA; Corneillie, Todd M [Campbell, CA; Xu, Jide [Berkeley, CA

    2012-05-08

    The present invention provides a novel class of macrocyclic compounds as well as complexes formed between a metal (e.g., lanthanide) ion and the compounds of the invention. Preferred complexes exhibit high stability as well as high quantum yields of lanthanide ion luminescence in aqueous media without the need for secondary activating agents. Preferred compounds incorporate hydroxy-isophthalamide moieties within their macrocyclic structure and are characterized by surprisingly low, non-specific binding to a variety of polypeptides such as antibodies and proteins as well as high kinetic stability. These characteristics distinguish them from known, open-structured ligands.

  8. Eu2+ activated persistent luminescent materials

    NARCIS (Netherlands)

    Dutczak, D.A.

    2013-01-01

    This thesis deals with luminescence and persistent luminescence of Eu2+ activated materials and aims at unraveling the mechanism behind the persistent luminescence, in particular the role of Dy3+ in the physical process leading to persistent luminescence. The second aim of this thesis is the

  9. Studies on synthesis, structural, luminescent and thermal properties of a new non-linear optical crystal: 4-amino-4H-1,2,4-triazol-1-ium-3-hydroxy-2,4,6-trinitrophenolate

    Energy Technology Data Exchange (ETDEWEB)

    Dhamodharan, P.; Sathya, K.; Dhandapani, M., E-mail: chemistrydhandapani@gmail.com

    2017-03-01

    A new organic proton transfer complex having NLO activity, 4-amino-4H-1,2,4-triazol-1-ium-3-hydroxy-2,4,6-trinitrophenolate (ATHTP), was crystallized to investigate the factors which stabilize the structure of the crystal. The compound crystallizes in triclinic system with space group P-1. Elemental analysis, thermal analysis, UV–Vis–NIR, FT-IR and NMR spectral analyses were carried out to characterize the crystal. Optical, spectral and thermal properties of the title crystal were analyzed to recommend the material for optical applications. Z-scan was used to measure the effective third-order nonlinear optical susceptibility and nonlinear refractive index. The crystal structure was determined using single crystal XRD method and the structure was optimized using Gaussian 09 program at B3LYP/6-311++G(d,p) level of basis set. This hydrogen bond interactions led to the increase in first-order hyperpolarizability of ATHTP and was 30 times greater than that of urea. Hirshfeld analyses surface analysis was carried out to explore intermolecular interactions in the crystalline state. - Highlights: • Single crystals were grown by slow evaporation solution growth technique. • N-H…O, O-H…O and C-H…O type of interactions lead to stable network. • The thermal stability of the compound was investigated by TG/DTA analyses. • The third-order nonlinear optical susceptibility is found to be 2.1×10{sup −7} esu. • Hirshfeld analyses explore covalent and non covalent interactions.

  10. User guide for luminescence sampling in archaeological and geological contexts

    Science.gov (United States)

    Nelson, Michelle S.; Gray, Harrison J.; Johnson, Jack A.; Rittenour, Tammy M.; Feathers, James K.; Mahan, Shannon

    2015-01-01

    Luminescence dating provides a direct age estimate of the time of last exposure of quartz or feldspar minerals to light or heat and has been successfully applied to deposits, rock surfaces, and fired materials in a number of archaeological and geological settings. Sampling strategies are diverse and can be customized depending on local circumstances, although all sediment samples need to include a light-safe sample and material for dose-rate determination. The accuracy and precision of luminescence dating results are directly related to the type and quality of the material sampled and sample collection methods in the field. Selection of target material for dating should include considerations of adequacy of resetting of the luminescence signal (optical and thermal bleaching), the ability to characterize the radioactive environment surrounding the sample (dose rate), and the lack of evidence for post-depositional mixing (bioturbation in soils and sediment). Sample strategies for collection of samples from sedimentary settings and fired materials are discussed. This paper should be used as a guide for luminescence sampling and is meant to provide essential background information on how to properly collect samples and on the types of materials suitable for luminescence dating.

  11. Mechanoresponsive Luminescent Molecular Assemblies: An Emerging Class of Materials.

    Science.gov (United States)

    Sagara, Yoshimitsu; Yamane, Shogo; Mitani, Masato; Weder, Christoph; Kato, Takashi

    2016-02-10

    The possibility to change the molecular assembled structures of organic and organometallic materials through mechanical stimulation is emerging as a general and powerful concept for the design of functional materials. In particular, the photophysical properties such as photoluminescence color, quantum yield, and emission lifetime of organic and organometallic fluorophores can significantly depend on the molecular packing, enabling the development of molecular materials with mechanoresponsive luminescence characteristics. Indeed, an increasing number of studies have shown in recent years that mechanical force can be utilized to change the molecular arrangement, and thereby the optical response, of luminescent molecular assemblies of π-conjugated organic or organometallic molecules. Here, the development of such mechanoresponsive luminescent (MRL) molecular assemblies consisting of organic or organometallic molecules is reviewed and emerging trends in this research field are summarized. After a brief introduction of mechanoresponsive luminescence observed in molecular assemblies, the concept of "luminescent molecular domino" is introduced, before molecular materials that show turn-on/off of photoluminescence in response to mechanical stimulation are reviewed. Mechanically stimulated multicolor changes and water-soluble MRL materials are also highlighted and approaches that combine the concept of MRL molecular assemblies with other materials types are presented in the last part of this progress report.

  12. Luminescence Dating of Sediments: An Increasingly Diverse Family of Methods and Range of Applications

    Science.gov (United States)

    Roberts, H. M.

    2015-12-01

    In recent years, the term 'luminescence dating' has expanded its meaning such that today it encompasses a range of luminescence dating methods and materials. Whilst the fundamental principles that underlie these different dating methods are essentially the same, namely that the event typically being recorded is the last exposure of the material to light or to heat, the various luminescence dating techniques do differ in their suitability in different situations. Today, in the field of luminescence dating of sediments, there are a number of minerals that can be used for dating (quartz and feldspar being the most commonly used), and for each mineral it is possible to obtain a number of different luminescence signals (some obtained using optical stimulation, and some obtained by heating). These different luminescence signals may build-up and deplete in the natural environment at different rates from each other, and can span quite different time ranges. Additionally, the scale of analysis used in luminescence dating can now be varied (ranging from single sand-sized grains to multiple grains), as can the size range of the materials used for dating (ranging from fine-silt, coarse-silt, and sand-sized grains, through to large clasts and rock surfaces). Having such flexibility in the range of minerals, luminescence signals, grain sizes, and the scales of analysis available for dating, means that it is now possible to optimise the materials and methods selected for dating in any particular study in response to the precise scientific question to be addressed, the time-range of interest, and the likely mechanisms of re-setting of the luminescence signal in the context that is to be dated. In this paper, the flexibility offered by the growing family of luminescence techniques will be outlined by considering some of the different minerals, luminescence signals, and dramatically different timescales (tens of years to millions of years) potentially available for sediment dating

  13. Monitoring Delamination of Plasma-Sprayed Thermal Barrier Coatings by Reflectance-Enhanced Luminescence

    Science.gov (United States)

    Eldridge, Jeffrey I.; Bencic, Timothy J.

    2006-01-01

    Highly scattering plasma-sprayed thermal barrier coatings (TBCs) present a challenge for optical diagnostic methods to monitor TBC delamination because scattering attenuates light transmitted through the TBC and usually degrades contrast between attached and delaminated regions of the TBC. This paper presents a new approach where reflectance-enhanced luminescence from a luminescent sublayer incorporated along the bottom of the TBC is used to identify regions of TBC delamination. Because of the higher survival rate of luminescence reflecting off the back surface of a delaminated TBC, the strong scattering exhibited by plasma-sprayed TBCs actually accentuates contrast between attached and delaminated regions by making it more likely that multiple reflections of luminescence off the back surface occur before exiting the top surface of the TBC. A freestanding coating containing sections designed to model an attached or delaminated TBC was prepared by depositing a luminescent Eu-doped or Er-doped yttria-stabilized zirconia (YSZ) luminescent layer below a plasma-sprayed undoped YSZ layer and utilizing a NiCr backing layer to represent an attached substrate. For specimens with a Eu-doped YSZ luminescent sublayer, luminescence intensity maps showed excellent contrast between unbacked and NiCr-backed sections even at a plasma-sprayed overlayer thickness of 300 m. Discernable contrast between unbacked and NiCr-backed sections was not observed for specimens with a Er-doped YSZ luminescent sublayer because luminescence from Er impurities in the undoped YSZ layer overwhelmed luminescence originating form the Er-doped YSZ sublayer.

  14. Luminescent DNA- and agar-based membranes.

    Science.gov (United States)

    Leones, R; Fernandes, M; Ferreira, R A S; Cesarino, I; Lima, J F; Carlos, L D; Bermudez, V de Zea; Magon, C J; Donoso, J P; Silva, M M; Pawlicka, A

    2014-09-01

    Luminescent materials containing europium ions are investigated for different optical applications. They can be obtained using bio-macromolecules, which are promising alternatives to synthetic polymers based on the decreasing oil resources. This paper describes studies of the DNA- and Agar-europium triflate luminescent membranes and its potential technological applications are expanded to electroluminescent devices. Polarized optical microscopy demonstrated that the samples are birefringent with submicrometer anisotropy. The X-ray diffraction analysis revealed predominantly amorphous nature of the samples and the atomic force microscopy images showed a roughness of the membranes of 409.0 and 136.1 nm for the samples of DNA10Eu and Agar1.11Eu, respectively. The electron paramagnetic resonance spectra of the DNA(n)Eu membranes with the principal lines at g ≈ 2.0 and g ≈ 4.8 confirmed uniform distribution of rare earth ions in a disordered matrix. Moreover, these strong and narrow resonance lines for the samples of DNA(n)Eu when compared to the Agar(n)Eu suggested a presence of paramagnetic radicals arising from the DNA matrix. The emission spectra suggested that the Eu3+ ions occupy a single local environment in both matrices and the excitation spectra monitored around the Eu emission lines pointed out that the Eu3+ ions in the Agar host were mainly excited via the broad band component rather than by direct intra-4f(6) excitation, whereas the opposite case occurred for the DNA-based sample.

  15. 光释光测年在海岸风沙地貌研究中的新进展%PROGRESS IN OPTICAL STIMULATED LUMINESCENCE DATING FOR COASTAL AEOLIAN GEOMORPHOLOGY RESEARCH : A REVIEW

    Institute of Scientific and Technical Information of China (English)

    谢丽; 张振克

    2011-01-01

    Since the mid-1980's much progress has been made in the use of optical stimulated luminescence (OSL) dating method into the studies of coastal aeolian sediments. OSL is one of the important dating methods used in Quaternary geology and archeology. In this paper the main achievements and advances in OSL dating of coastal aeolian sediments were summarized. With the development of the stimulating light source and OSL dating methods itself, more accurate dating results of the coastal aeolian sediments could be obtained. The improvement of OSL dating methods, such as the single aliquot additive dose protocol and the single aliquot regenerative dose protocol,has expanded the dating range and enhanced the precision of OSL dating. The youngest age of coastal aeolian sediments,which have been dated by OSL dating,is within 10 years,and the oldest one is over 900 thousands years. A great deal of researches in this field focus on the evolution of coastal aeolian dune and its relationship with global climate changes in the past. With the ongoing development of OSL dating technology, sandy coast evolution, regional climatic changes and sea level changes will be studied deeply and widely in the near future.%20世纪80年代中期以来,光释光技术广泛应用于海岸风沙沉积物测年研究中,并取得了丰硕的成果.随着光释光测年激发光源和单片再生剂量方法的快速发展,海岸风沙光释光测年的时间范围不断扩大,测年的准确度逐渐提高,已测得最年轻的海岸风沙沉积物的年龄小于10年,最老的年龄达到90多万年.利用光释先年龄重建海岸风沙演化进程及其与全球气候变化关系的研究,正成为学术界关注的焦点,光释光测年方法在将来的砂质海岸演化、区域气候变化及海平面变化等全球变化问题的研究中具有广阔发展前景.

  16. Eu2+ activated persistent luminescent materials

    OpenAIRE

    Dutczak, D.A.

    2013-01-01

    This thesis deals with luminescence and persistent luminescence of Eu2+ activated materials and aims at unraveling the mechanism behind the persistent luminescence, in particular the role of Dy3+ in the physical process leading to persistent luminescence. The second aim of this thesis is the preparation and characterization of persistent luminescence phosphors emitting at different colors, especially yellow and red, where there is a need for better afterglow materials. A range of aluminates, ...

  17. Tunable Luminescence Contrast of Na0.5Bi4.5Ti4O15:Re (Re = Sm, Pr, Er) Photochromics by Controlling the Excitation Energy of Luminescent Centers.

    Science.gov (United States)

    Zhang, Qiwei; Zhang, Yao; Sun, Haiqin; Geng, Wei; Wang, Xusheng; Hao, Xihong; An, Shengli

    2016-12-21

    High luminescent switching contrast of photochromic materials is extremely important in improving the sensitivity and resolution of optical switches and high-density optical data storage devices. To date, conventional methods, such as tuning absorption and emission bands based on electron or resonance energy transfer mechanisms in well-known organic photochromic molecules or compounds, have routinely been adopted to tune luminescent switching behavior. However, these strategies and mechanisms are not effectively applied to luminescence switching in inorganic materials because their crystal structures differ strongly from those of organic materials. In this paper, we report a new method to significantly tune the luminescent switching contrast by modifying the excitation energy of luminescent centers in a newly synthesized photochromism material: Na0.5Bi4.5Ti4O15:Re (Re = Sm, Pr, Er). A significant enhancement of luminescence switching contrast was achieved when the luminescent centers were excited by low energy photons at a given irradiation wavelength, intensity, and time, compared with high excitation energy photons. The trend "the lower the excitation energy, the higher the luminescence switching contrast" is universal in different rare earth ion-doped Na0.5Bi4.5Ti4O15 ferroelectrics. The changes in the luminescent switching contrast based on excitation energy are ascribed to nonradiative energy transfer from the luminescent center to the color center by dipole-dipole interactions according to Dexter theory. This possible utilization of excitation energy at lower energy levels is usually less destructive to both information recording and the recording material itself during luminescent readout processes while achieving higher luminescence switching contrast.

  18. Luminescence decay of porous silicon

    Science.gov (United States)

    Chen, X.; Uttamchandani, D.; Sander, D.; O'Donnell, K. P.

    1993-04-01

    The luminescence decay pattern of porous silicon samples prepared by electrochemical etching is characterised experimentally by a non-exponential profile, a strong dependence on temperature and an absence of spectral diffusion. We describe this luminescence as carrier-dopping-assisted recombination. Following the correlation function approach to non-dispersive transport developed by Scher and co-workers [Physics Today 41 (1991) 26], we suggest a simple derivation of analytical functions which accurately describes the anomalous luminescence decay of porous silicon, and show that this model includes exponential and Kohlrausch [Pogg. Ann. Phys. 119 (1863) 352] (stretched-exponential) relaxations as special cases.

  19. Luminescent and Non-Luminescent Solar Concentrators: Challenges andd Progress

    NARCIS (Netherlands)

    De Boer, D.K.G.

    2012-01-01

    Luminescent concentrators would allow for high concentration if losses by reabsorption and escape could be minimized. We present new phosphors and filters that facilitate this. Another type of lightguide-based concentrators, diffraction-based, is discussed as well.

  20. Luminescent and Non-Luminescent Solar Concentrators: Challenges andd Progress

    NARCIS (Netherlands)

    De Boer, D.K.G.

    2012-01-01

    Luminescent concentrators would allow for high concentration if losses by reabsorption and escape could be minimized. We present new phosphors and filters that facilitate this. Another type of lightguide-based concentrators, diffraction-based, is discussed as well.

  1. Simultaneous quasi-one-dimensional propagation and tuning of upconversion luminescence through waveguide effect.

    Science.gov (United States)

    Gao, Dangli; Tian, Dongping; Zhang, Xiangyu; Gao, Wei

    2016-02-29

    Luminescence-based waveguide is widely investigated as a promising alternative to conquer the difficulties of efficiently coupling light into a waveguide. But applications have been still limited due to employing blue or ultraviolet light as excitation source with the lower penetration depth leading to a weak guided light. Here, we show a quasi-one-dimensional propagation of luminescence and then resulting in a strong luminescence output from the top end of a single NaYF4:Yb(3+)/Er(3+) microtube under near infrared light excitation. The mechanism of upconversion propagation, based on the optical waveguide effect accompanied with energy migration, is proposed. The efficiency of luminescence output is highly dependent on the concentration of dopant ions, excitation power, morphology, and crystallinity of tube as an indirect evidence of the existence of the optical actived waveguide effect. These findings provide the possibility for the construction of upconversion fiber laser.

  2. Simultaneous quasi-one-dimensional propagation and tuning of upconversion luminescence through waveguide effect

    Science.gov (United States)

    Gao, Dangli; Tian, Dongping; Zhang, Xiangyu; Gao, Wei

    2016-02-01

    Luminescence-based waveguide is widely investigated as a promising alternative to conquer the difficulties of efficiently coupling light into a waveguide. But applications have been still limited due to employing blue or ultraviolet light as excitation source with the lower penetration depth leading to a weak guided light. Here, we show a quasi-one-dimensional propagation of luminescence and then resulting in a strong luminescence output from the top end of a single NaYF4:Yb3+/Er3+ microtube under near infrared light excitation. The mechanism of upconversion propagation, based on the optical waveguide effect accompanied with energy migration, is proposed. The efficiency of luminescence output is highly dependent on the concentration of dopant ions, excitation power, morphology, and crystallinity of tube as an indirect evidence of the existence of the optical actived waveguide effect. These findings provide the possibility for the construction of upconversion fiber laser.

  3. Highly Nonlinear Luminescence Induced by Gold Nanoparticles on Glass Surfaces with Continuous-Wave Laser Illumination

    CERN Document Server

    Wu, Yong; Toro, Ligia; Stefani, Enrico

    2015-01-01

    We report on highly nonlinear luminescence being observed from individual spherical gold nanoparticles immobilized on a borosilicate glass surface and illuminated by continuous-wave (CW) lasers with relatively low power. The nonlinear luminescence shows optical super-resolution beyond the diffraction limit in three dimensions compared to the scatting of the excitation laser light. The luminescence intensity from most nanoparticles is proportional to the 5th--7th power of the excitation laser power and has wide excitation and emission spectra across the visible wavelength range. Strong nonlinear luminescence is only observed near the glass surface. High optical nonlinearity excited by low CW laser power is related to a long-lived dark state of the gold nanoparticles, where the excitation light is strongly absorbed. This phenomenon has potential biological applications in super-resolution and deep tissue imaging.

  4. Mechanism of red-luminescence flash in CdS single crystals irradiated by electrons

    Energy Technology Data Exchange (ETDEWEB)

    Bogdanyuk, N.S.; Galushka, A.P.; Ostapenko, S.S.; Shejnkman, M.K. (AN Ukrainskoj SSR, Kiev. Inst. Poluprovodnikov)

    1984-02-01

    Results of investigations into ''red''-luminescence flash (lambdasub(x)=720 nm) in cadmium sulfide, irradiated by electrons at 77 K, are presented. Measurement of spectra of stationary photoluminescence and its excitation, as well as flash luminescence, its pumping and stimulation along with temperature flash dependences enabled to suggest a new mechanism of optical luminescence stimulation, based on the model of complex center of flash luminescense. The mechanism consists in modulation of probabilities of intercenter electron transitions, when charge state of one of components of the complex center changes.

  5. Radiation-induced growth and isothermal decay of infrared-stimulated luminescence from feldspar

    DEFF Research Database (Denmark)

    Guralnik, Benny; Li, Bo; Jain, Mayank

    2015-01-01

    Optically stimulated luminescence (OSL) ages can determine a wide range of geological events or processes, such as the timing of sediment deposition, the exposure duration of a rock surface, or the cooling rate of bedrock. The accuracy of OSL dating critically depends on our capability to describe...... the growth and decay of laboratory-regenerated luminescence signals. Here we review a selection of common models describing the response of infrared stimulated luminescence (IRSL) of feldspar to constant radiation and temperature as administered in the laboratory. We use this opportunity to introduce...

  6. Luminescence decay and the absorption cross section of individual single-walled carbon nanotubes.

    Science.gov (United States)

    Berciaud, Stéphane; Cognet, Laurent; Lounis, Brahim

    2008-08-15

    The absorption cross section of highly luminescent individual single-walled carbon nanotubes is determined using time-resolved and cw luminescence spectroscopy. A mean value of approximately 1 x 10(-17) cm2 per carbon atom is obtained for (6,5) tubes excited at their second optical transition, and corroborated by single tube photothermal absorption measurements. Biexponential luminescence decays are systematically observed, with short and long lifetimes around 45 and 250 ps. This behavior is attributed to the band edge exciton fine structure with a dark level lying a few meV below a bright one.

  7. Quenching the radiation induced luminescence in quartz fibers under light monitoring

    CERN Document Server

    Demenkov, P V; Stepanov, V A; Stepanov, P A

    2002-01-01

    Measurements of the luminescence intensity in the optical fiber with the quartz glass core by the reactor pulsed irradiation in the visible range are carried out. Decrease in the intensity of the radiation-induced luminescence with growth of the sounding light intensity is determined by sounding the light guide by the laser radiation (the wave length of 532 and 632 nm). The decrease in the luminescence intensity takes place by the wave lengths greater, smaller or equal to the sounding light wave length

  8. Zirconia-based luminescent organic-inorganic hybrid materials with ternary europium (III) complexes bonded

    Science.gov (United States)

    Yang, Jing; Li, Zhiqiang; Xu, Yang; Wang, Yige

    2016-05-01

    In this work, a novel red-emitting organic-inorganic hybrid material with europium (III) lanthanide β-diketonate complexes linked to a zirconia was reported, which was realized by adduct formation with zirconia-tethered terpyridine moieties. Luminescence enhancement of the hybrid material has been observed compared with pure Eu(tta)3·2H2O. Transparent and strongly luminescent thin films based on PMMA were also prepared at room temperature, which are highly luminescent under UV-light irradiation and possess a promising prospect in the area of optics.

  9. Influence of Sintering Conditions on the Optical Properties of Long Afterglow Luminescence Glass%烧成条件对长余辉蓄光玻璃光学性能的影响

    Institute of Scientific and Technical Information of China (English)

    林元华; 陈清明; 张中太; 唐子龙

    2000-01-01

    SrAl2O4:Eu,Dy long afterglow luminescence powders and low melting point B-Si glass were employed as the sources, and synthesized the long afterglow luminescence glass at suitable conditions. The results of experiments indicate that sintering temperature and soaking time have great influence on the properties of the glass, and the luminescence effect will decrease as sintering temperature and soaking time increase. In this experiment, sintering temperatures were chosen at 750~800℃ and soaking time was maintained about 10min. Under those conditions, a serious of luminescence glass with good properties was prepared. The decay curves indicate that the luminescent properties of the luminescence glass decrease compared with its original phosphor powders. The analytical results of SEM indicate that the glass prepared at low temperature containes more luminescent powders for long afterglow than that of prepared at relatively high temperature.%以SrAl2O4:Eu,Dy长余辉发光粉体和低熔点硼硅酸盐玻璃为原料,在一定条件下合成了长余辉蓄光玻璃.研究结果表明,烧成温度和保温时间对该玻璃的发光效果影响较大.温度越高,保温时间越长,由于空气的氧化作用,蓄光玻璃的发光效果越差.本试验控制烧成温度在750~800℃间,保温时间在10min以内,能合成性能较好的蓄光玻璃.余辉衰减曲线表明蓄光玻璃的发光性能较之原始发光粉体有所下降.SEM分析表明,低温合成的蓄光玻璃中,所含能继续保持发光性质的粉体料,明显比高温合成样要多.

  10. NIR persistent luminescence of lanthanide ion-doped rare-earth oxycarbonates: the effect of dopants.

    Science.gov (United States)

    Caratto, Valentina; Locardi, Federico; Costa, Giorgio Andrea; Masini, Roberto; Fasoli, Mauro; Panzeri, Laura; Martini, Marco; Bottinelli, Emanuela; Gianotti, Enrica; Miletto, Ivana

    2014-10-22

    A series of luminescent rare-earth ion-doped hexagonal II-type Gd oxycarbonate phosphors Gd2-xRExO2CO3 (RE = Eu(3+), Yb(3+), Dy(3+)) have been successfully synthesized by thermal decomposition of the corresponding mixed oxalates. The Yb(3+) doped Gd-oxycarbonate has evidenced a high persistent luminescence in the NIR region, that is independent from the temperature and makes this materials particular attractive as optical probes for bioimaging.

  11. [Study of PbSe quantum dots for use in luminescence solar concentrators].

    Science.gov (United States)

    Hu, Wen-Jia; Zhang, Yu; Jian, Xu; Wang, Jing-Kang

    2013-02-01

    With the study of the characteristic of luminescence solar concentrator, a simple and practicable Monte Carlo simulation system was invented based on ray tracing method. PbSe quantum dots were successfully introduced into this system, and the optical parameter and quantum dots concentration were simulated and optimized. The cost per unit of the solar cell base on luminescence solar concentrator was investigated, and it was found that the cost of traditional solar cells can be reduced by 49.2%.

  12. Cristallochimie et luminescence de quelques oxydes et fluorures de l'indium

    OpenAIRE

    Gaewdang, Thitinai

    1993-01-01

    With the prospect of application for the detection of low energy solar neutrinos the crystal chemistry and optical properties of some oxides and fluorides of indium have been investigated. Single crystals of the selected compounds have been prepared by several appropriate methods, i.e. flux growth, chemical vapor transport or Bridgman. The crystal structure determinations and luminescence studies were performed either on powders or on single crystals. The intrinsic luminescence of In2TiO5, In...

  13. Model of laser-induced temperature changes in solid-state optical refrigerators

    Science.gov (United States)

    Patterson, W. M.; Sheik-Bahae, M.; Epstein, R. I.; Hehlen, M. P.

    2010-03-01

    We present an efficient and numerically stable method to calculate time-dependent, laser-induced temperature distributions in solids and provide a detailed description of the computational procedure and its implementation. This study combines the two-dimensional heat equation with laser-induced heat generation and temperature-dependent luminescence. The time-dependent optical response of a system is obtained numerically by the Crank-Nicolson method. This general model is applied to the specific case of optical refrigeration in ytterbium (Yb3+) doped fluorozirconate glass (ZBLAN). The laser-induced temperature change upon optical pumping and the respective transient luminescence response are calculated and compared to experimental data. The model successfully predicts the zero-crossing temperature, the net quantum efficiency, and the functional shape of the transients. We find that the laser-cooling transients have a fast and a slow component that are determined by the excited-state lifetime of the luminescent ion and the thermal properties of the bulk, respectively. The tools presented here may find application in the design of a wide range of optical and optoelectronic devices.

  14. Lanthanide-based luminescence biolabelling.

    Science.gov (United States)

    Sy, Mohamadou; Nonat, Aline; Hildebrandt, Niko; Charbonnière, Loïc J

    2016-04-14

    Luminescent lanthanide complexes display unrivalled spectroscopic properties, which place them in a special category in the luminescent toolbox. Their long-lived line-like emission spectra are the cornerstones of numerous analytical applications ranging from ultrasensitive homogeneous fluoroimmunoassays to the study of molecular interactions in living cells with multiplexed microscopy. However, achieving such minor miracles is a result of years of synthetic efforts and spectroscopic studies to understand and gather all the necessary requirements for the labels to be efficient. This feature article intends to survey these criteria and to discuss some of the most important examples reported in the literature, before explaining in detail some of the applications of luminescent lanthanide labels to bioanalysis and luminescence microscopy. Finally, the emphasis will be put on some recent applications that hold great potential for future biosensing.

  15. Ultrabright Luminescence from Gold Nanoclusters: Rigidifying the Au(I)-Thiolate Shell.

    Science.gov (United States)

    Pyo, Kyunglim; Thanthirige, Viraj Dhanushka; Kwak, Kyuju; Pandurangan, Prabhu; Ramakrishna, Guda; Lee, Dongil

    2015-07-01

    Luminescent nanomaterials have captured the imagination of scientists for a long time and offer great promise for applications in organic/inorganic light-emitting displays, optoelectronics, optical sensors, biomedical imaging, and diagnostics. Atomically precise gold clusters with well-defined core-shell structures present bright prospects to achieve high photoluminescence efficiencies. In this study, gold clusters with a luminescence quantum yield greater than 60% were synthesized based on the Au22(SG)18 cluster, where SG is glutathione, by rigidifying its gold shell with tetraoctylammonium (TOA) cations. Time-resolved and temperature-dependent optical measurements on Au22(SG)18 have shown the presence of high quantum yield visible luminescence below freezing, indicating that shell rigidity enhances the luminescence quantum efficiency. To achieve high rigidity of the gold shell, Au22(SG)18 was bound to bulky TOA that resulted in greater than 60% quantum yield luminescence at room temperature. Optical measurements have confirmed that the rigidity of gold shell was responsible for the luminescence enhancement. This work presents an effective strategy to enhance the photoluminescence efficiencies of gold clusters by rigidifying the Au(I)-thiolate shell.

  16. Optically stimulated luminescence in retrospective dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Murray, A.S.

    2002-01-01

    of this programme, including the evaluation of the single-aliquot regenerative-dose (SAR) measurement protocol with brick quartz and the determination of dose-depth profiles in building materials as a guide to determining the mean energy of the incident radiation. Investigations into heated materials are most...... advanced, and a lower detection limit for quartz extracted from Chernobyl bricks was determined to be aliquot and single-grain techniques have been used...

  17. Detrimental nonlocality in luminescence measurements

    Science.gov (United States)

    Pluska, Mariusz; Czerwinski, Andrzej

    2017-08-01

    Luminescence studies are used to investigate the local properties of various light-emitting materials. A critical issue of these studies is presented that the signals often lack all advantages of luminescence-studies of high locality, and may originate from an extended spatial region of even a few millimeters in size or the whole sample, i.e., places other than intended for investigation. This is a key problem for research and development in photonics. Due to this nonlocality, information indicating defects, irregularities, nonuniformities and inhomogeneities is lost. The issue refers to typical structures with a strong built-in electric field. Such fields exist intentionally in most photonic structures and occur unintentionally in many other materials investigated by applied physics. We reveal [using test samples prepared with focused ion beam (FIB) on an AlGaAs/GaAs laser heterostructure with an InGaAs quantum well (QW)] that nonlocality increases at low temperatures. This is contrary to the widely expected outcome, as low-temperature luminescence measurements are usually assumed to be free from disturbances. We explain many effects observed due to nonlocality in luminescence studies and prove that separation of the investigated area by focused ion beam milling is a practical solution enabling truly local luminescence measurements. All conclusions drawn using the example of cathodoluminescence are useful for other luminescence techniques.

  18. Thermal dependence of time-resolved blue light stimulated luminescence in α-Al2O3:C

    DEFF Research Database (Denmark)

    Pagonis, Vasilis; Ankjærgaard, Christina; Jain, Mayank

    2013-01-01

    This paper presents time-resolved optically stimulated luminescence (TR-OSL) experiments in the important dosimetric material Al2O 3:C. During these experiments short pulses (0.5 s) of light from blue LEDs (470 nm) are followed by relaxation periods (2.5 s) of the charge carriers at different......-dependent phosphorescence signal, the delayed-OSL described previously for this material. The temperature dependent luminescence lifetimes obtained from analysis of the optical stimulation period are identical to those obtained from the corresponding relaxation period. However, the values of these luminescence lifetimes...

  19. Estimation of luminescence lifetime in frequency domain

    Institute of Scientific and Technical Information of China (English)

    Zhang Fu-Jun; Xu Zheng; Zhao Su-Ling; Lou Zhi-Dong; Yang Sheng-Yi; Xu Xu-Rong

    2006-01-01

    Absorption is the origin of luminescence. But it must be noticed that the lifetime of luminescence might reversely influence the rate of absorption. In this paper, it is reported that the luminescence intensity of copper and manganese changes with the driving frequency at constant voltage. The variation of luminescent intensity depends only on the lifetime of luminescence but not on the type of quenching or other factors. Generally the rate of absorption is dominantly determined by the material property and the lifetime of luminescence centres, the absorption of shorter lifetime centre will be larger than that of the longer lifetime centre at the same excited condition.

  20. Stable distributions

    CERN Document Server

    Janson, Svante

    2011-01-01

    We give some explicit calculations for stable distributions and convergence to them, mainly based on less explicit results in Feller (1971). The main purpose is to provide ourselves with easy reference to explicit formulas. (There are no new results.)

  1. Instant luminescence chronologies? High resolution luminescence profiles using a portable luminescence reader

    OpenAIRE

    Bateman, M. D.; Stein, S.; Ashurst, R.A.; Selby, K.

    2015-01-01

    Establishing a robust chronology is fundamental to most palaeoenvironmental studies. However, the number and positioning of dated points is critical. Using a portable luminescence reader, it is possible to rapidly generate high resolution down core relative age profiles. Profiles of portable luminescence data from two coastal dunes were evaluated and compared with the results of particle size analysis, stratigraphy, and an independent historical chronology. Results show that, even in young sa...

  2. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen

  3. Luminescence associated with stacking faults in GaN

    OpenAIRE

    Lähnemann, Jonas; Jahn, Uwe; Brandt, Oliver; Flissikowski, Timur; Dogan, Pinar; Grahn, Holger T.

    2014-01-01

    Basal-plane stacking faults are an important class of optically active structural defects in wurtzite semiconductors. The local deviation from the 2H stacking of the wurtzite matrix to a 3C zinc-blende stacking induces a bound state in the gap of the host crystal, resulting in the localization of excitons. Due to the two-dimensional nature of these planar defects, stacking faults act as quantum wells, giving rise to radiative transitions of excitons with characteristic energies. Luminescence ...

  4. Luminescence dosimetry: recent developments in theory and applications

    Energy Technology Data Exchange (ETDEWEB)

    McKeever, S.W.S. [Department of Physics, Oklahoma State University, Stillwater, OK 74078-3072 (United States)

    2000-07-01

    Thermally and optically stimulated luminescence have been used in applications in solid state physics, radiation dosimetry and geological dating for several decades. This paper gives a generalized description of these methods in terms of non-equilibrium thermodynamics and in doing so highlights similarities and differences between the methods. Recent advances in both the theory and application of the techniques are highlighted with numerous specific examples. (Author)

  5. A New Optic Technology for Measuring Oxygen Dissolved in Water: Luminescence Dissolved Oxygen (LDO); Nueva tecnologia optica para la medicion de oxigeno disuelto en agua: oxigeno disuelto por luminiscencia (LDO)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    Continual measurement of oxygen in the active sludge tank is a very important parameter is the biological treatment of waste waters. Traditional electrochemical sensors are based on polarographic or galvanic cells, a technique which produces electrolyte consumption and progressive deterioration of the anode. Both effects inevitable lead to a drift in the measurement signal, which requires periodical calibration. Lange has developed a completely new technique for its new LDO sensor for measuring oxygen concentration in waste waters. This technique is based on the luminescent radiation of a luminescent substance (luminophore) and reduces the determination to the purely physical measurement of time, so that, in theory it is free of drift and there is no need for the use to calibrate the sensor. (Author)

  6. Eu(2+) luminescence in strontium aluminates.

    Science.gov (United States)

    Dutczak, D; Jüstel, T; Ronda, C; Meijerink, A

    2015-06-21

    The luminescence properties of Eu(2+) doped strontium aluminates are reported and reviewed for a variety of aluminates, viz. SrAl12O19, SrAl4O7, Sr4Al14O25, SrAl2O4 and Sr3Al2O6. The aim of the research is to investigate the role of local coordination and covalency of the aluminate host lattice, related to the Sr/Al ratio, on the optical properties of the Eu(2+) ion. The UV and VUV excited luminescence spectra as well as luminescence decay curves were recorded to characterize the luminescence properties of the investigated aluminates. The emission of Eu(2+) ions varies over a wide spectral range, from ultraviolet (UV) to red, for the series of aluminates. The variation in emission color can be related to the crystal-field splitting of the 5d levels and the covalent interaction with the surrounding oxygen anions. In the least covalent material, viz. SrAl12O19:Eu(2+), narrow line emission due to the (6)P7/2-(8)S7/2 transition occurs at 4 K, indicating that the 4f(6)5d excited state is situated above the (6)P7/2(4f(7)) excited state around 360 nm. The most alkaline material, viz. Sr3Al2O6:Eu(2+) is the most covalent host and exhibits several d-f emission bands in the yellow to red spectral range due to the Eu(2+) ions located on different crystallographic Sr(2+) sites. The Eu(2+) emission spectra in the other aluminates confirm the trend that with increasing Sr/Al ratio the Eu(2+) emission shifts to longer wavelengths. Interesting differences are observed for the Eu(2+) from different crystallographic sites which cannot always be related with apparent differences in the first oxygen coordination sphere. The discussion gives insight into how in a similar class of materials, strontium aluminates, the emission color of Eu(2+) can be tuned over a wide spectral region.

  7. Europium Luminescence Used for Logic Gate and Ions Sensing with Enoxacin As the Antenna.

    Science.gov (United States)

    Lu, Lixia; Chen, Chuanxia; Zhao, Dan; Sun, Jian; Yang, Xiurong

    2016-01-19

    Luminescent lanthanide ion complexes have received increasing attention because of their unique optical properties. Herein, we discovered that the luminescence of europium(III) (Eu(3+)) could be regulated by Ag(+) and SCN(-) in seconds with enoxacin (ENX) as the antenna. Under given conditions, only the simultaneous introduction of Ag(+) and SCN(-) could remarkably enhance the luminescence intensity of Eu(3+)-ENX complexes. This phenomenon has been exploited to design an "AND" logic gate and specific luminescence turn-on assays for sensitively sensing Ag(+) and SCN(-) for the first time. Furthermore, the addition of S(2-) resulted in efficient luminescence quenching of the Eu(3+)/ENX/Ag(+)/SCN(-) system due to the strong affinity between Ag(+) and S(2-). Thus, a new luminescent sensing platform for S(2-) was established, which exhibited excellent selectivity and high sensitivity. S(2-) could be detected within the concentration range of 100 nM to 12.5 μM with a detection limit of 60 nM. Such sensing system features simplicity, rapidity, and flexibility. Moreover, this proposed Eu(3+)-based luminescent assay could be successfully applied in the real environmental water sample analysis.

  8. Luminescent chemosensors for amines and ammonia based on Eu(III) chelate complexes

    Science.gov (United States)

    Sergeev, Alexander A.; Voznesenskiy, Sergey S.; Petrochenkova, Nataliya V.; Shishov, Alexander S.; Leonov, Andrei A.; Emelina, Tatiana B.; Mirochnik, Anatolii G.; Kulchin, Yuri N.

    2016-11-01

    Here we report a novel luminescent sensor for amines and ammonia based on Eu(III) tris-β-benzoylacetonate complexes obtained in various conditions. It has been revealed that interaction of Eu(III) tris-β-benzoylacetonate with analyte vapor results in increase of the Eu(III) luminescence intensity. Exposure of Eu(III) complexes to ammonia and methylamine vapors results in a rapid increase of the emission and excitation spectra intensity and a rapid recovery, almost to the initial value, when the sample is exposed to air. Moreover, luminescence decay time value of Eu(III) complexes is in dependence on analyte presence and increase in ammonia atmosphere and decrease under purging of pure air. The dependences of sensor response features upon preparation conditions were shown. The mechanism of the analyte vapors effect on Eu(III) luminescence intensification has been suggested using the data of IR spectroscopy and quantum chemistry calculations. The mechanism of luminescence sensitization consists in bonding of an analyte molecule with a water molecule into the coordination sphere of Eu(III). As a result, the bond of a water molecule with the luminescence center weakens and the blockage of the quenching of luminescence on OH-vibrations takes place. The obtained data can be used for development of sensor materials with selective optical sensitivity to ecologically harmful vapours of organic and inorganic compounds.

  9. Turning on the Light: Lessons from Luminescence

    Science.gov (United States)

    O'Hara, Patricia B.; Engelson, Carol; St. Peter, Wayne

    2005-01-01

    Some of the processes by which light is emitted without a simultaneous change in temperature are discussed and is classified as luminescence or cold light. Luminescent processes include triboluminescence, fluorescence, phosphorescence, chemiluminescence, and bioluminescence.

  10. Progress in chemical luminescence-based biosensors: A critical review.

    Science.gov (United States)

    Roda, Aldo; Mirasoli, Mara; Michelini, Elisa; Di Fusco, Massimo; Zangheri, Martina; Cevenini, Luca; Roda, Barbara; Simoni, Patrizia

    2016-02-15

    Biosensors are a very active research field. They have the potential to lead to low-cost, rapid, sensitive, reproducible, and miniaturized bioanalytical devices, which exploit the high binding avidity and selectivity of biospecific binding molecules together with highly sensitive detection principles. Of the optical biosensors, those based on chemical luminescence detection (including chemiluminescence, bioluminescence, electrogenerated chemiluminescence, and thermochemiluminescence) are particularly attractive, due to their high-to-signal ratio and the simplicity of the required measurement equipment. Several biosensors based on chemical luminescence have been described for quantitative, and in some cases multiplex, analysis of organic molecules (such as hormones, drugs, pollutants), proteins, and nucleic acids. These exploit a variety of miniaturized analytical formats, such as microfluidics, microarrays, paper-based analytical devices, and whole-cell biosensors. Nevertheless, despite the high analytical performances described in the literature, the field of chemical luminescence biosensors has yet to demonstrate commercial success. This review presents the main recent advances in the field and discusses the approaches, challenges, and open issues, with the aim of stimulating a broader interest in developing chemical luminescence biosensors and improving their commercial exploitation.

  11. Quantifying self-absorption losses in luminescent solar concentrators.

    Science.gov (United States)

    Ten Kate, Otmar M; Hooning, Koen M; van der Kolk, Erik

    2014-08-10

    Analytical equations quantifying self-absorption losses in circular luminescent solar concentrators (LSCs) are presented that can easily be solved numerically by commercial math software packages. With the quantum efficiency, the absorption and emission spectra of a luminescent material, the LSC dimensions, and the refractive index as the only input parameters, the model gives an accurate account of the decrease of LSC efficiency due to self-absorption as a function of LSC radius, thickness, and luminescence quantum efficiency. Results give insight into how many times light is reabsorbed and reemitted, the red shift of the emission spectrum, and on how multiple reabsorptions and reemissions are distributed over the LSC. As an example case the equations were solved for a circular LSC containing a Lumogen F Red 305 dye with 80% luminescence quantum efficiency, and it follows that for an LSC with a 50 cm radius the self-absorption reduces the number of photons reaching the LSC edge by a factor of four compared to the case when there would be no self-absorption. The equations can just as well be solved for any material for which the optical properties are known like type I and type II quantum dots.

  12. Development of optical marker for polyolefin processes; Desenvolvimento de marcador optico para processamento de poliolefinas

    Energy Technology Data Exchange (ETDEWEB)

    Marchini, Leonardo Guedes

    2013-08-01

    Research and publications about luminescent polymers have been developed in the last years for the academic innovation; however the industrial application has been very limited in this area. Processed Optical markers are few explored due the difficult to process luminescent polymeric materials with stable luminescence. The materials used to process luminescent polypropylene (PP) were polyamide 6 (PA6) doped with europium complex [Eu(tta){sub 3}(H{sub 2}O){sub 2}] obtained through the dilution and casting process. The polyolefins because they are inert, do not fit the common procedure of doping, in consequence, in this work luminescent polypropylene was indirectly prepared by polyamide 6 doped with europium complex through extrusion process. Product characterization was done using Thermal gravimetry analysis (TG), Differential Scanning Calorimetric (DSC), X-Ray Diffraction (XRD), Infrared spectroscopy (FTIR) and spectro fluorescence of emission and excitation. The blend PP/PA6:Eu(tta){sub 3} presented luminescent properties, after semi-industrial process, as observed in the narrow bands of intra configuration transitions- 4f{sup 6} relatives to energy levels {sup 7}F{sub 0} {yields} {sup 5}L{sub 6} (394nm), {sup 7}F{sub 0} {yields} {sup 5}D{sub 3} (415nm), {sup 7}F{sub 0} {yields} {sup 5}D{sub 2} (464nm), {sup 7}F{sub 0} {yields} {sup 5}D{sub 1} (525nm) e {sup 7}F{sub 0} {yields} {sup 5}D{sub 0} (578nm) of emission spectrum. Red light of the pellets or film is emitted when excited in UV lamp (365nm). TG results showed under O{sub 2} atmosphere that PP doped with PA6:Eu(tta){sub 3} was more stable than pure PP. In this work was processed luminescent PP/PA6:Eu(tta){sub 3} with properties of thermal and photo stability which can be used as optical marker in polymer processing. (author)

  13. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  14. Self absorption in luminescent solar concentrators

    NARCIS (Netherlands)

    Krumer, Z.

    2014-01-01

    Luminescent solar concentrators are photovoltaic devices made of thin transparent material, in which luminescent particles are dispersed. The incident light enters the device through its large facets and is subsequently absorbed by the luminescent particles, which re-emit it whilst changing its dire

  15. Preparation and characterization of bifunctional dendrimer modified Fe{sub 3}O{sub 4}/CdTe nanoparticles with both luminescent and superparamagnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiuling, E-mail: wxling_self@163.com [Department of Chemical and Biological Engineering, Suzhou University of Science and Technology, Suzhou 215009 (China); Gu, Yinjun; Dong, Shuling [Department of Chemical and Biological Engineering, Suzhou University of Science and Technology, Suzhou 215009 (China); Zhao, Qin [School of Chemistry and Chemical Engineering, Nantong University, Nantong, Jiangsu 226019 (China); Liu, Yongjian [Department of Chemical and Biological Engineering, Suzhou University of Science and Technology, Suzhou 215009 (China)

    2015-10-15

    Highlights: • The fluorescent superparamagnetic dendrimeric Fe{sub 3}O{sub 4}/CdTe nanoparticles are synthesized in this paper. • The synthesized nanocomposites maintain excellent magnetic properties. • The synthesized nanocomposites maintain highly luminescent markers with narrow emission bands. - Abstract: Magnetic nanoparticles Fe{sub 3}O{sub 4} were prepared by hydrothermal coprecipitation of ferric and ferrous ions using NaOH. The surface modification of Fe{sub 3}O{sub 4} nanoparticle by dendrimers has rendered the nanoparticle surface with enriched amine groups which facilitated the adsorption and conjugation of thioglycolic acid (TGA) modified CdTe quantum dots to form a stable hybrid nanostructure. Three generations (first generation: G0F, second generation: G1F, third generation: G3F) of bifunctional dendrimeric Fe{sub 3}O{sub 4}/CdTe nanoparticles were successfully prepared using this technique and characterized by microscopy. The optical and magnetic properties of the dendrimeric Fe{sub 3}O{sub 4}/CdTe nanoparticle were also investigated. The microscopic study reveals 3 different sizes for 3 generations, 16 nm (G0F), 31 nm (G1F) and 47 nm (G3F). Among three generations of nanoparticles, the G1F has the best optical property with a luminescent quantum yield of 25.6% and the G0F has the best magnetic property with a saturation magnetization of 19.3 emμ/g.

  16. Lanthanide-doped luminescent nano-bioprobes: from fundamentals to biodetection.

    Science.gov (United States)

    Liu, Yongsheng; Tu, Datao; Zhu, Haomiao; Ma, En; Chen, Xueyuan

    2013-02-21

    Trivalent lanthanide (Ln(3+))-doped luminescent inorganic nanoparticles (NPs), characterized by long-lived luminescence, large Stokes and/or anti-Stokes shifts, narrow emission bands and high photochemical stability, are considered to be promising candidates as luminescent bioprobes in biomedicine and biotechnology. In this feature article, we provide a brief overview of the most recent advances in Ln(3+)-doped luminescent inorganic NPs as sensors, which covers from their chemical and physical fundamentals to biodetection, such as controlled synthesis methodology, surface modification chemistry, optical physics, and their promising applications in diverse bioassays, with an emphasis on heterogeneous and homogeneous in vitro biodetection. Finally, some of the most important emerging trends and future efforts toward this active research field are also proposed.

  17. Annealing effects on luminescent properties of Eu3+ doped Gd2Zr2O7 nanopowders

    Directory of Open Access Journals (Sweden)

    Rabasović M.S.

    2015-01-01

    Full Text Available In this report presented are structure, morphology and luminescence properties of nanopowders based on gadolinium zirconium oxide (Gd2Zr2O7 doped by europium ions (Eu3+. The nanopowders were prepared using a flame combustion method, the most frequently used process due to the simplicity and low cost of the synthesis procedures and also due to the possibility of tailoring the size and morphology of particles. The produced material is suitable for various optical devices. The luminescence properties of synthesized nanopowders were characterized by emission spectra and luminescence lifetimes obtained by using the streak camera system. Moreover, emission spectra were obtained and compared for powders as-obtained and after additional annealing at 1200o C. Luminescence emission spectra clearly show peaks characteristic for the strong emission lines at 611 nm and 630 nm corresponding to the 5D0 → 7F2 long lived transition. [Projekat Ministarstva nauke Republike Srbije, br. OI 171020

  18. Unpredictably Stable

    DEFF Research Database (Denmark)

    Failla, Virgilio; Melillo, Francesca; Reichstein, Toke

    2014-01-01

    Is entrepreneurship a more stable career choice for high employment turnover individuals? We find that a transition to entrepreneurship induces a shift towards stayer behavior and identify job matching, job satisfaction and lock-in effects as main drivers. These findings have major implications...

  19. A luminescent nanocrystal stress gauge

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Charina; Koski, Kristie; Olson, Andrew; Alivisatos, Paul

    2010-10-25

    Microscale mechanical forces can determine important outcomes ranging from the site of material fracture to stem cell fate. However, local stresses in a vast majority of systems cannot be measured due to the limitations of current techniques. In this work, we present the design and implementation of the CdSe/CdS core/shell tetrapod nanocrystal, a local stress sensor with bright luminescence readout. We calibrate the tetrapod luminescence response to stress, and use the luminescence signal to report the spatial distribution of local stresses in single polyester fibers under uniaxial strain. The bright stress-dependent emission of the tetrapod, its nanoscale size, and its colloidal nature provide a unique tool that may be incorporated into a variety of micromechanical systems including materials and biological samples to quantify local stresses with high spatial resolution.

  20. Quantitative luminescence imaging system

    Science.gov (United States)

    Batishko, C. R.; Stahl, K. A.; Fecht, B. A.

    The goal of the Measurement of Chemiluminescence project is to develop and deliver a suite of imaging radiometric instruments for measuring spatial distributions of chemiluminescence. Envisioned deliverables include instruments working at the microscopic, macroscopic, and life-sized scales. Both laboratory and field portable instruments are envisioned. The project also includes development of phantoms as enclosures for the diazoluminomelanin (DALM) chemiluminescent chemistry. A suite of either phantoms in a variety of typical poses, or phantoms that could be adjusted to a variety of poses, is envisioned. These are to include small mammals (rats), mid-sized mammals (monkeys), and human body parts. A complete human phantom that can be posed is a long-term goal of the development. Taken together, the chemistry and instrumentation provide a means for imaging rf dosimetry based on chemiluminescence induced by the heat resulting from rf energy absorption. The first delivered instrument, the Quantitative Luminescence Imaging System (QLIS), resulted in a patent, and an R&D Magazine 1991 R&D 100 award, recognizing it as one of the 100 most significant technological developments of 1991. The current status of the project is that three systems have been delivered, several related studies have been conducted, two preliminary human hand phantoms have been delivered, system upgrades have been implemented, and calibrations have been maintained. Current development includes sensitivity improvements to the microscope-based system; extension of the large-scale (potentially life-sized targets) system to field portable applications; extension of the 2-D large-scale system to 3-D measurement; imminent delivery of a more refined human hand phantom and a rat phantom; rf, thermal and imaging subsystem integration; and continued calibration and upgrade support.