WorldWideScience

Sample records for hybrid coherent anti-stokes

  1. Coherent anti-Stokes Raman spectroscopy: Understanding the essentials

    Science.gov (United States)

    Ariunbold, Gombojav O.; Altangerel, Narangerel

    2016-12-01

    This paper is a brief overview to coherent anti- Stokes Raman spectroscopic technique and introduces the strengths and barriers to its use all based on the interpretation of simple theoretical formulae. The use of the Gaussian ultrashort pulses is highlighted as a practical elucidatory reconstruction tool of coherent Raman spectra. The paper presents the integral formulae for coherent anti-Stokes and Stokes Raman scattering, and discusses the closed-form solutions, its complex error function, and the delay time formula for enhancement of the inferred pure coherent Raman spectra. As an example, the timeresolved coherent Stokes Raman scattering experimental observations are quantitatively elucidated.Understanding the essentials of coherent Raman spectroscopy, therefore, promotes the importance of a number of experiments including the ones utilizing a broadband excitation with a narrowband delayed probing for successful background suppression.

  2. Coherent Anti-Stokes Raman Scattering Heterodyne Interferometry

    CERN Document Server

    Bredfeldt, J S; Vinegoni, C; Hambir, S; Boppart, S A

    2003-01-01

    A new interferometric technique is demonstrated for measuring Coherent Anti-Stokes Raman Scattering (CARS) signals. Two forward-directed CARS signals are generated, one in each arm of an interferometer. The deterministic nature of the CARS process allows for these two signals, when spatially and temporally overlapped, to interfere with one another. Heterodyne detection can therefore be employed to increase the sensitivity in CARS signal detection. In addition, nonlinear CARS interferometry will facilitate the use of this spectroscopic technique for molecular contrast in Optical Coherence Tomography (OCT).

  3. Localized thermal mapping using coherent anti-Stokes Raman spectroscopy.

    Science.gov (United States)

    Beier, Hope T; Noojin, Gary D; Rockwell, Benjamin A

    2012-08-01

    Coherent anti-Stokes Raman scattering (CARS) spectroscopy is explored as a tool for obtaining micro-scale thermal measurements. A single femtosecond oscillator is used to pump a photonic crystal fiber to provide the broadband Stokes pulse. The CARS signals from the broad OH-stretching modes between 3000 and 3600 cm(-1) are shown to correlate with temperature with an accuracy of ± 1°C for water and ± 1.5°C for phosphate-buffered saline. Local variation of temperature is mapped on a microscopic level, using black-dyed microspheres as thermal sources.

  4. Quantitative coherent anti-Stokes Raman scattering (CARS) microscopy.

    Science.gov (United States)

    Day, James P R; Domke, Katrin F; Rago, Gianluca; Kano, Hideaki; Hamaguchi, Hiro-o; Vartiainen, Erik M; Bonn, Mischa

    2011-06-23

    The ability to observe samples qualitatively at the microscopic scale has greatly enhanced our understanding of the physical and biological world throughout the 400 year history of microscopic imaging, but there are relatively few techniques that can truly claim the ability to quantify the local concentration and composition of a sample. We review coherent anti-Stokes Raman scattering (CARS) as a quantitative, chemically specific, and label-free microscopy. We discuss the complicating influence of the nonresonant response on the CARS signal and the various experimental and mathematical approaches that can be adopted to extract quantitative information from CARS. We also review the uses to which CARS has been employed as a quantitative microscopy to solve challenges in material and biological science.

  5. Coherent anti-Stokes Raman scattering microscopy of single nanodiamonds.

    Science.gov (United States)

    Pope, Iestyn; Payne, Lukas; Zoriniants, George; Thomas, Evan; Williams, Oliver; Watson, Peter; Langbein, Wolfgang; Borri, Paola

    2014-11-01

    Nanoparticles have attracted enormous attention for biomedical applications as optical labels, drug-delivery vehicles and contrast agents in vivo. In the quest for superior photostability and biocompatibility, nanodiamonds are considered one of the best choices due to their unique structural, chemical, mechanical and optical properties. So far, mainly fluorescent nanodiamonds have been utilized for cell imaging. However, their use is limited by the efficiency and costs in reliably producing fluorescent defect centres with stable optical properties. Here, we show that single non-fluorescing nanodiamonds exhibit strong coherent anti-Stokes Raman scattering (CARS) at the sp(3) vibrational resonance of diamond. Using correlative light and electron microscopy, the relationship between CARS signal strength and nanodiamond size is quantified. The calibrated CARS signal in turn enables the analysis of the number and size of nanodiamonds internalized in living cells in situ, which opens the exciting prospect of following complex cellular trafficking pathways quantitatively.

  6. Coherent anti-Stokes Raman scattering microscopy of single nanodiamonds

    Science.gov (United States)

    Pope, Iestyn; Payne, Lukas; Zoriniants, George; Thomas, Evan; Williams, Oliver; Watson, Peter; Langbein, Wolfgang; Borri, Paola

    2014-11-01

    Nanoparticles have attracted enormous attention for biomedical applications as optical labels, drug-delivery vehicles and contrast agents in vivo. In the quest for superior photostability and biocompatibility, nanodiamonds are considered one of the best choices due to their unique structural, chemical, mechanical and optical properties. So far, mainly fluorescent nanodiamonds have been utilized for cell imaging. However, their use is limited by the efficiency and costs in reliably producing fluorescent defect centres with stable optical properties. Here, we show that single non-fluorescing nanodiamonds exhibit strong coherent anti-Stokes Raman scattering (CARS) at the sp3 vibrational resonance of diamond. Using correlative light and electron microscopy, the relationship between CARS signal strength and nanodiamond size is quantified. The calibrated CARS signal in turn enables the analysis of the number and size of nanodiamonds internalized in living cells in situ, which opens the exciting prospect of following complex cellular trafficking pathways quantitatively.

  7. Imaging properties of coherent anti-Stokes Raman scattering microscope

    Institute of Scientific and Technical Information of China (English)

    Yuan Jing-He; Xiao Fan-Rong; Wang Gui-Ying; Xu Zhi-Zhan

    2005-01-01

    The coherent anti-Stokes Raman scattering (CARS) microscope with the combination of confocal and CARS techniques is a remarkable alternative for imaging chemical or biological specimens that neither fluoresce nor tolerate labelling. CARS is a nonlinear optical process, the imaging properties of CARS microscopy will be very different from the conventional confocal microscope. In this paper, the intensity distribution and the polarization property of the optical field near the focus was calculated. By using the Green function, the precise analytic solution to the wave equation of a Hertzian dipole source was obtained. We found that the intensity distributions vary considerably with the different experimental configurations and the different specimen shapes. So the conventional description of microscope (e.g. the point spread function) will fail to describe the imaging properties of the CARS microscope.

  8. Coherent anti-Stokes Raman scattering under electric field stimulation

    Science.gov (United States)

    Capitaine, Erwan; Ould Moussa, Nawel; Louot, Christophe; Lefort, Claire; Pagnoux, Dominique; Duclère, Jean-René; Kaneyasu, Junya F.; Kano, Hideaki; Duponchel, Ludovic; Couderc, Vincent; Leproux, Philippe

    2016-12-01

    We introduce an experiment using electro-CARS, an electro-optical method based on the combination of ultrabroadband multiplex coherent anti-Stokes Raman scattering (M-CARS) spectroscopy and electric field stimulation. We demonstrate that this method can effectively discriminate the resonant CARS signal from the nonresonant background owing to a phenomenon of molecular orientation in the sample medium. Such molecular orientation is intrinsically related to the induction of an electric dipole moment by the applied static electric field. Evidence of the electro-CARS effect is obtained with a solution of n -alkanes (CnH2 n +2 , 15 ≤n ≤40 ), for which an enhancement of the CARS signal-to-noise ratio is achieved in the case of CH2 and CH3 symmetric/asymmetric stretching vibrations. Additionally, an electric-field-induced second-harmonic generation experiment is performed in order to corroborate the orientational organization of molecules due to the electric field excitation. Finally, we use a simple mathematical approach to compare the vibrational information extracted from electro-CARS measurements with spontaneous Raman data and to highlight the impact of electric stimulation on the vibrational signal.

  9. Single-pulse coherent anti-Stokes Raman spectroscopy via fiber Bragg grating

    Science.gov (United States)

    Oh, Seung Ryeol; Park, Joo Hyun; Kwon, Won Sik; Kim, Jin Hwan; Kim, Kyung-Soo; Lee, Jae Yong; Kim, Soohyun

    2016-03-01

    Fiber Bragg grating is used in a variety of applications. In this study, we suggest compact, cost-effective coherent anti- Stokes Raman spectroscopy which is based on the pulse shaping methods via commercialized fiber Bragg grating. The experiment is performed incorporating a commercialized femtosecond pulse laser system (MICRA, Coherent) with a 100 mm length of 780-HP fiber which is inscribed 50 mm of Bragg grating. The pump laser for coherent anti-Stokes Raman spectroscopy has a bandwidth of 90 nm and central wavelength of 815 nm with a notch shaped at 785 nm. The positive chirped pulse is compensated by chirped mirror set. We compensate almost 14000 fs2 of positive group delay dispersion for the transform-limited pulse at the sample position. The pulse duration was 15 fs with average power of 50 mW, and showed an adequate notch shape. Finally, coherent anti-Stokes Raman signals are observed using a spectrometer (Jobin Yvon Triax320 and TE-cooled Andor Newton EMCCD). We obtained coherent anti-Stokes Raman signal of acetone sample which have Raman peak at the spectral finger-print region. In conclusion, the proposed method is more simple and cost-effective than the methods of previous research which use grating pairs and resonant photonic crystal slab. Furthermore, the proposed method can be used as endoscope application.

  10. Coherent anti-Stokes Raman scattering microscopy for pharmaceutics: a shift in the right direction

    NARCIS (Netherlands)

    Fussell, Andrew Luke

    2014-01-01

    This dissertation demonstrates coherent anti-Stokes Raman scattering (CARS) microscopy as a tool in pharmaceutical solid state development. CARS microscopy is a nonlinear optical imaging technique that uses inelastic scattering of light to provide chemically specific imaging. CARS microscopy is suit

  11. Coherent anti-Stokes Raman scattering (CARS) microscopy driving the future of loaded mesoporous silica imaging

    NARCIS (Netherlands)

    Fussell, A.L.; Mah, Pei Ting; Offerhaus, Herman L.; Niemi, Sanna-Mari; Salonen, Jarno; Santos, Helder A.; Strachan, Clare

    2014-01-01

    This study reports the use of variants of coherent anti-Stokes Raman scattering (CARS) microscopy as a novel method for improved physicochemical characterization of drug-loaded silica particles. Ordered mesoporous silica is a biomaterial that can be loaded to carry a number of biochemicals,

  12. Coherent anti-Stokes Raman scattering microscopy with a photonic crystal fiber based light source

    DEFF Research Database (Denmark)

    Paulsen, H.N.; Hilligsøe, Karen Marie; Thøgersen, J.

    2003-01-01

    A coherent anti-Stokes Raman scattering microscope based on a Ti:sapphire femtosecond oscillator and a photonic crystal fiber is demonstrated. The nonlinear response of the fiber is used to generate the additional wavelength needed in the Raman process. The applicability of the setup is demonstra...... is demonstrated by imaging of micrometer-sized polystyrene beads....

  13. Broadband multiplex coherent anti-Stokes Raman scattering microscopy employing photonic-crystal fibers

    DEFF Research Database (Denmark)

    Andresen, Esben Ravn; Paulsen, Henrik Nørgaard; Birkedal, Victoria;

    2006-01-01

    We demonstrate spectral multiplex coherent anti-Stokes Raman scattering (CARS) spectroscopy and microscopy based on a single Ti:sapphire oscillator and a nonlinear photonic-crystal fiber (PCF). The Stokes pulse is generated by spectral conversion of the laser pulse in a PCF. The pump pulse...

  14. Coherent anti-stokes raman scattering microscopy to monitor drug dissolution in different oral pharmaceutical tablets

    NARCIS (Netherlands)

    Jurna, M.; Windbergs, M.; Strachan, C.J.; Hartsuiker, Liesbeth; Otto, Cornelis; Kleinebudde, P.; Herek, Jennifer Lynn; Offerhaus, Herman L.

    2009-01-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy is used to visualize the release of a model drug (theophylline) from a lipid (tripalmitin) based tablet during dissolution. The effects of transformation and dissolution of the drug are imaged in real time. This study reveals that the manufactu

  15. Method and system to measure temperature of gases using coherent anti-stokes doppler spectroscopy

    Science.gov (United States)

    Rhodes, Mark

    2013-12-17

    A method of measuring a temperature of a noble gas in a chamber includes providing the noble gas in the chamber. The noble gas is characterized by a pressure and a temperature. The method also includes directing a first laser beam into the chamber and directing a second laser beam into the chamber. The first laser beam is characterized by a first frequency and the second laser beam is characterized by a second frequency. The method further includes converting at least a portion of the first laser beam and the second laser beam into a coherent anti-Stokes beam, measuring a Doppler broadening of the coherent anti-Stokes beam, and computing the temperature using the Doppler broadening.

  16. Combustion Diagnostics by Pure Rotational Coherent Anti-Stokes Raman Scattering

    Science.gov (United States)

    Leipertz, Alfred; Seeger, Thomas

    Since its first use in Richard Chang's laboratory in 1982 in a comparative study with vibrational coherent anti-Stokes Raman scattering (VCARS) in a flame, pure rotational coherent anti-Stokes Raman scattering (RCARS) has gained tremendous importance for gas temperature and relative species concentration measurements in combustion diagnostics. The field of application covers basic studies on diagnostics development and on flame research as well as its use in technical combustion systems, e.g., for the determination of the gas-phase temperature in the vaporizing spray of a gasoline direct injection (GDI) injector or for the simultaneous measurement of gas temperature and exhaust-gas-recirculation rate (EGR rate) in a homogeneous charge compression ignition (HCCI) engine. An overview is given on the fundamentals of the technique and on its most important technical applications.

  17. Design of supercontinuum source for coherent anti-Stokes Raman scattering microscopy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hui; CHANG Sheng-jiang; ZHANG Yan-xin; ZHAO Xiang-ting

    2008-01-01

    A new method to obtain supemontinuum(SC)source for multiplex coherent anti-stokes Raman scattering(CARS)micros-copy is proposed.The nonlinear propagation in photonic-crystal fibers(PCF)of femtosecond pulse laser with central wavelength at 800.9 nm is studied with scalar wave theory.Based on the incident laser power and dispersion of PCF,super broadband source for multiplex CARS microscopy is designed.

  18. Coherent anti-stokes Raman scattering microscopy: chemical imaging for biology and medicine.

    Science.gov (United States)

    Evans, Conor L; Xie, X Sunney

    2008-01-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy is a label-free imaging technique that is capable of real-time, nonperturbative examination of living cells and organisms based on molecular vibrational spectroscopy. Recent advances in detection schemes, understanding of contrast mechanisms, and developments of laser sources have enabled superb sensitivity and high time resolution. Emerging applications, such as metabolite and drug imaging and tumor identification, raise many exciting new possibilities for biology and medicine.

  19. Supercontinuum generation for coherent anti- Stokes Raman scattering microscopy with photonic crystal fibers

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Isomäki, Antti; Hansen, Kim P.

    2011-01-01

    Photonic crystal fiber (PCF) designs with two zero-dispersion wavelengths (ZDWs) are experimentally investigated in order to suggest a novel PCF for coherent anti-Stokes Raman scattering (CARS) microscopy. From our investigation, we select the optimum PCF design and demonstrate a tailored spectrum...... analysis, the nonlinear effects responsible for the spectral broadening are explained to be soliton fission processes, dispersive waves, and stimulated Raman scattering....

  20. Pure-rotational H2 thermometry by ultrabroadband coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Courtney, Trevor L.; Bohlin, Alexis; Patterson, Brian D.; Kliewer, Christopher J.

    2017-06-01

    Coherent anti-Stokes Raman spectroscopy (CARS) is a sensitive technique for probing highly luminous flames in combustion applications to determine temperatures and species concentrations. CARS thermometry has been demonstrated for the vibrational Q-branch and pure-rotational S-branch of several small molecules. Practical advantages of pure-rotational CARS, such as multi-species detection, reduction of coherent line mixing and collisional narrowing even at high pressures, and the potential for more precise thermometry, have motivated experimental and theoretical advances in S-branch CARS of nitrogen (N2), for example, which is a dominant species in air-fed combustion processes. Although hydrogen (H2) is of interest given its prevalence as a reactant and product in many gas-phase reactions, laser bandwidth limitations have precluded the extension of CARS thermometry to the H2 S-branch. We demonstrate H2 thermometry using hybrid femtosecond/picosecond pure-rotational CARS, in which a broadband pump/Stokes pulse enables simultaneous excitation of the set of H2 S-branch transitions populated at flame temperatures over the spectral region of 0-2200 cm-1. We present a pure-rotational H2 CARS spectral model for data fitting and compare extracted temperatures to those from simultaneously collected N2 spectra in two systems of study: a heated flow and a diffusion flame on a Wolfhard-Parker slot burner. From 300 to 650 K in the heated flow, the H2 and N2 CARS extracted temperatures are, on average, within 2% of the set temperature. For flame measurements, the fitted H2 and N2 temperatures are, on average, within 5% of each other from 300 to 1600 K. Our results confirm the viability of pure-rotational H2 CARS thermometry for probing combustion reactions.

  1. Quantitative interpretation of time-resolved coherent anti-Stokes Raman spectroscopy with all Gaussian pulses

    CERN Document Server

    Ariunbold, Gombojav O

    2016-01-01

    Coherent Raman scattering spectroscopy is studied purposely, with the Gaussian ultrashort pulses as a hands-on elucidatory extraction tool of the clean coherent Raman resonant spectra from the overall measured data contaminated with the non-resonant four wave mixing background. The integral formulae for both the coherent anti-Stokes and Stokes Raman scattering are given in the semiclassical picture, and the closed-form solutions in terms of a complex error function are obtained. An analytic form of maximum enhancement of pure coherent Raman spectra at threshold time delay depending on bandwidth of probe pulse is also obtained. The observed experimental data for pyridine in liquid-phase are quantitatively elucidated and the inferred time-resolved coherent Raman resonant results are reconstructed with a new insight.

  2. Broadband multiplex coherent anti-Stokes Raman scattering microscopy employing photonic-crystal fibers

    DEFF Research Database (Denmark)

    Andresen, Esben Ravn; Paulsen, Henrik Nørgaard; Birkedal, Victoria

    2006-01-01

    We demonstrate spectral multiplex coherent anti-Stokes Raman scattering (CARS) spectroscopy and microscopy based on a single Ti:sapphire oscillator and a nonlinear photonic-crystal fiber (PCF). The Stokes pulse is generated by spectral conversion of the laser pulse in a PCF. The pump pulse...... is either a highly chirped pulse or a pulse spectrally compressed in a PCF. A region of the Raman spectrum from 800 to 4000 cm(-1) is accessible with two different PCFs. Spectral resolution improvement by 1 order of magnitude over a transform-limited pump pulse utilizing a chirped or spectrally compressed...

  3. Spectral model of time-domain coherent anti-Stokes Raman scattering

    CERN Document Server

    Marrocco, Michele

    2014-01-01

    We show that the increasingly popular nonlinear optical technique of time-domain coherent anti-Stokes Raman scattering (CARS), which is usually understood in terms of the semiclassical time-dependent third-order polarization, can be equally explained in terms of the time-delayed version of the Yuratich equation so popular in traditional frequency-domain CARS. The method brings out the strong dependence of CARS time traces and time-delayed CARS lineshapes on the spectral envelope of the probe laser electric field. Examples are analytically shown for experimental results that are otherwise treated by means of numerical methods only.

  4. A versatile setup using femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yujie, E-mail: styojm@physics.tamu.edu [Texas A& M University, College Station, Texas 77843 (United States); Voronine, Dmitri V.; Sokolov, Alexei V. [Texas A& M University, College Station, Texas 77843 (United States); Baylor University, Waco, Texas 76798 (United States); Scully, Marlan O. [Texas A& M University, College Station, Texas 77843 (United States); Baylor University, Waco, Texas 76798 (United States); Princeton University, Princeton, New Jersey 08544 (United States)

    2015-08-15

    We report a versatile setup based on the femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering. The setup uses a femtosecond Ti:Sapphire oscillator source and a folded 4f pulse shaper, in which the pulse shaping is carried out through conventional optical elements and does not require a spatial light modulator. Our setup is simple in alignment, and can be easily switched between the collinear single-beam and the noncollinear two-beam configurations. We demonstrate the capability for investigating both transparent and highly scattering samples by detecting transmitted and reflected signals, respectively.

  5. Polarized multiplex coherent anti-Stokes Raman scattering using a picosecond laser and a fiber supercontinuum.

    Science.gov (United States)

    Michel, Sébastien; Courjaud, Antoine; Mottay, Eric; Finot, Christophe; Dudley, John; Rigneault, Hervé

    2011-02-01

    We perform multiplex coherent anti-Stokes Raman scattering (CARS) micro-spectroscopy with a picosecond pulsed laser and a broadband supercontinuum (SC) generated in photonic crystal fiber. CARS signal stability is achieved using an active fiber coupler that avoids thermal and mechanical drifts. We obtain multiplex CARS spectra for test liquids in the 600-2000 cm(-1) spectral range. In addition we investigate the polarization dependence of the CARS spectra when rotating the pump beam linear polarization state relative to the linearly polarized broad stokes SC. From these polarization measurements we deduce the Raman depolarization ratio, the resonant versus nonresonant contribution, the Raman resonance frequency, and the linewidth.

  6. Interference spectroscopy with coherent anti-Stokes Raman scattering of noisy broadband pulses

    CERN Document Server

    Shapiro, Evgeny A; Milner, Valery

    2011-01-01

    We propose a new technique for comparing two Raman active samples. The method employs optical interference of the signals generated via coherent anti-Stokes Raman scattering (CARS) of broadband laser pulses with noisy spectra. It does not require spectrally resolved detection, and no prior knowledge about either the Raman spectrum of the samples, or the spectrum of the incident light is needed. We study the proposed method theoretically, and demonstrate it in a proof-of-principle experiment on Toluene and ortho-Xylene samples.

  7. Experimental Investigation on Selective Excitation of Two-Pulse Coherent Anti-Stokes Raman Scattering

    Institute of Scientific and Technical Information of China (English)

    LI Xia; ZHANG Hui; ZHANG Xiang-Yun; ZHANG Shi-An; WANG Zu-Geng; SUN Zhen-Rong

    2008-01-01

    Selective excitation of coherent anti-Stokes Raman scattering from the benzene solution is achieved by adaptive pulse shaping based on genetic algorithm, and second harmonic generation frequency-resolved optical gating (SHG-FROG) technique is adopted to characterize the original and optimal laser pulses. The mechanism for two-pulse coherent mode-selective excitation of Raman scattering is experimentally investigated by modulating the pump pulse in the frequency domain, and it is indicated that two-pulse coherent mode-selective excitation of Raman scattering mainly depends on the effective frequency components of the pump pulse related to specific vibrational mode. The experimental results suggest that two-pulse CARS has good signal-to-background ratio and high sensitivity, and it has attractive potential applications in the complicated molecular system.

  8. Next generation hazard detection via ultrafast coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Brady, John J.; Pellegrino, Paul M.

    2013-05-01

    Multiplex coherent anti-Stokes Raman spectroscopy (MCARS) is used to detect an explosive precursor material and two chemical warfare simulants. The spectral bandwidth of the femtosecond laser pulse used in these studies is sufficient to coherently and simultaneously drive all the vibrational modes in the molecule of interest. The research performed here demonstrates that MCARS has the capability to detect an explosive precursor (e.g., acetone) and hazardous materials, such as dimethyl methylphosphonate and 2-chloroethyl methyl sulfide (a sarin and a mustard gas chemical warfare simulant, respectively), with high specificity. Evidence shows that MCARS is capable of overcoming common the sensitivity limitations of spontaneous Raman scattering, thus allowing for the detection of the target material in milliseconds with standard USB spectrometers as opposed to seconds with intensified spectrometers. The exponential increase in the number of scattered photons suggests that the MCARS technique may be capable of overcoming range detection challenges common to spontaneous Raman scattering.

  9. Raman and coherent anti-Stokes Raman scattering microspectroscopy for biomedical applications

    Science.gov (United States)

    Krafft, Christoph; Dietzek, Benjamin; Schmitt, Michael; Popp, Jürgen

    2012-04-01

    A tutorial article is presented for the use of linear and nonlinear Raman microspectroscopies in biomedical diagnostics. Coherent anti-Stokes Raman scattering (CARS) is the most frequently applied nonlinear variant of Raman spectroscopy. The basic concepts of Raman and CARS are introduced first, and subsequent biomedical applications of Raman and CARS are described. Raman microspectroscopy is applied to both in-vivo and in-vitro tissue diagnostics, and the characterization and identification of individual mammalian cells. These applications benefit from the fact that Raman spectra provide specific information on the chemical composition and molecular structure in a label-free and nondestructive manner. Combining the chemical specificity of Raman spectroscopy with the spatial resolution of an optical microscope allows recording hyperspectral images with molecular contrast. We also elaborate on interfacing Raman spectroscopic tools with other technologies such as optical tweezing, microfluidics and fiber optic probes. Thereby, we aim at presenting a guide into one exciting branch of modern biophotonics research.

  10. Shaping femtosecond coherent anti-Stokes Raman spectra using optimal control theory.

    Science.gov (United States)

    Pezeshki, Soroosh; Schreiber, Michael; Kleinekathöfer, Ulrich

    2008-04-21

    Optimal control theory is used to tailor laser pulses which enhance a femtosecond time-resolved coherent anti-Stokes Raman scattering (fs-CARS) spectrum in a certain frequency range. For this aim the optimal control theory has to be applied to a target state distributed in time. Explicit control mechanisms are given for shaping either the Stokes or the probe pulse in the four-wave mixing process. A simple molecule for which highly accurate potential energy surfaces are available, namely molecular iodine, is used to test the procedure. This approach of controlling vibrational motion and delivering higher intensities to certain frequency ranges might also be important for the improvement of CARS microscopy.

  11. Delivery of picosecond lasers in multimode fibers for coherent anti-Stokes Raman scattering imaging.

    Science.gov (United States)

    Wang, Zhiyong; Yang, Yaliang; Luo, Pengfei; Gao, Liang; Wong, Kelvin K; Wong, Stephen T C

    2010-06-07

    We investigated the possibility of using standard commercial multimode fibers (MMF), Corning SMF28 fibers, to deliver picosecond excitation lasers for coherent anti-Stokes Raman scattering (CARS) imaging. We theoretically and/or experimentally analyzed issues associated with the fiber delivery, such as dispersion length, walk-off length, nonlinear length, average threshold power for self-phase modulations, and four-wave mixing (FWM). These analyses can also be applied to other types of fibers. We found that FWM signals are generated in MMF, but they can be filtered out using a long-pass filter for CARS imaging. Finally, we demonstrated that MMF can be used for delivery of picosecond excitation lasers in the CARS imaging system without any degradation of image quality.

  12. Quantitative, Comparable Coherent Anti-Stokes Raman Scattering (CARS) Spectroscopy: Correcting Errors in Phase Retrieval

    CERN Document Server

    Camp, Charles H; Cicerone, Marcus T

    2015-01-01

    Coherent anti-Stokes Raman scattering (CARS) microspectroscopy has demonstrated significant potential for biological and materials imaging. To date, however, the primary mechanism of disseminating CARS spectroscopic information is through pseudocolor imagery, which explicitly neglects a vast majority of the hyperspectral data. Furthermore, current paradigms in CARS spectral processing do not lend themselves to quantitative sample-to-sample comparability. The primary limitation stems from the need to accurately measure the so-called nonresonant background (NRB) that is used to extract the chemically-sensitive Raman information from the raw spectra. Measurement of the NRB on a pixel-by-pixel basis is a nontrivial task; thus, reference NRB from glass or water are typically utilized, resulting in error between the actual and estimated amplitude and phase. In this manuscript, we present a new methodology for extracting the Raman spectral features that significantly suppresses these errors through phase detrending ...

  13. Quantitative assessment of spinal cord injury using circularly polarized coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Bae, Kideog; Zheng, Wei; Huang, Zhiwei

    2017-08-01

    We report the quantitative assessment of spinal cord injury using the circularly polarized coherent anti-Stokes Raman scattering (CP-CARS) technique together with Stokes parameters in the Poincaré sphere. The pump and Stokes excitation beams are circularly polarized to suppress both the linear polarization-dependent artifacts and the nonresonant background of tissue CARS imaging, enabling quantitative CP-CARS image analysis. This study shows that CP-CARS imaging uncovers significantly increased phase retardance of injured spinal cord tissue as compared to normal tissue, suggesting that CP-CARS is an appealing label-free imaging tool for determining the degree of tissue phase retardance, which could serve as a unique diagnostic parameter associated with nervous tissue injury.

  14. Automated identification of subcellular organelles by coherent anti-stokes Raman scattering.

    Science.gov (United States)

    El-Mashtoly, Samir F; Niedieker, Daniel; Petersen, Dennis; Krauss, Sascha D; Freier, Erik; Maghnouj, Abdelouahid; Mosig, Axel; Hahn, Stephan; Kötting, Carsten; Gerwert, Klaus

    2014-05-06

    Coherent anti-Stokes Raman scattering (CARS) is an emerging tool for label-free characterization of living cells. Here, unsupervised multivariate analysis of CARS datasets was used to visualize the subcellular compartments. In addition, a supervised learning algorithm based on the "random forest" ensemble learning method as a classifier, was trained with CARS spectra using immunofluorescence images as a reference. The supervised classifier was then used, to our knowledge for the first time, to automatically identify lipid droplets, nucleus, nucleoli, and endoplasmic reticulum in datasets that are not used for training. These four subcellular components were simultaneously and label-free monitored instead of using several fluorescent labels. These results open new avenues for label-free time-resolved investigation of subcellular components in different cells, especially cancer cells.

  15. Coherent anti-Stokes Raman scattering microscopy (CARS): Instrumentation and applications

    Energy Technology Data Exchange (ETDEWEB)

    Djaker, Nadia [Institut Fresnel, Mosaic team, CNRS UMR 6133, Universite Paul Cezanne (Aix-Marseille III), F-1397 Marseille Cedex 20 (France); Lenne, Pierre-Francois [Institut Fresnel, Mosaic team, CNRS UMR 6133, Universite Paul Cezanne (Aix-Marseille III), F-1397 Marseille Cedex 20 (France); Marguet, Didier [Centre d' Immunologie de Marseille-Luminy, Universite de la Mediterranee, Case 906, F-13288 Marseille Cedex 9 (France); INSERM, UMR631, Marseille (France); CNRS, UMR6102, Marseille (France); Colonna, Anne [L' Oreal Recherche, Aulnay Sous bois (France); Hadjur, Christophe [L' Oreal Recherche, Aulnay Sous bois (France); Rigneault, Herve [Institut Fresnel, Mosaic team, CNRS UMR 6133, Universite Paul Cezanne (Aix-Marseille III), F-1397 Marseille Cedex 20 (France)]. E-mail: herve.rigneault@fresnel.fr

    2007-02-01

    Recent advances in laser physics have permitted the development of a new kind of microscopy based on stimulated Raman scattering. This new technique known as Coherent anti-Stokes Raman scattering (CARS) microscopy allows vibrational imaging with high sensitivity, high spectral resolution and three-dimensional sectioning capabilities. We review recent advances in CARS microscopy, with applications to chemical and biological systems. We also present an application of CARS microscopy with high optical resolution and spectral selectivity, in resolving structures in surface ex vivo stratum corneum by looking at the CH{sub 2} stretching vibrational band. A strong CARS signal is backscattered from an intense forward generated CARS signal in thick samples. This makes noninvasive imaging of deep structures possible, without labeling or chemical treatments.

  16. Low-concentration chemical sensing using surface-enhanced coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Hua, Xia; Sinyukov, Alexander; Traverso, Andrew; Veronine, Dmitri; Wang, Kai; Xia, Hui; Yang, Wenlong; Yuan, Luqi; Sokolov, Alexei; Scully, Marlan

    2010-10-01

    Measurements of surface enhanced coherent anti-Stokes Raman spectra (CARS) of cyclohexane are carried out. Random aggregates of gold nanoparticles for field enhancement were deposited on a glass substrate and were characterized using atomic force microscopy (AFM). Surface enhancement of the CARS signal by gold nanoparticles is observed. This technique can be used to detect low amounts of chemicals with a higher sensitivity compared to the conventional surface-enhanced Raman spectroscopy (SERS). The lowest detected concentration of cyclohexane in a thin film of methanol was 1%. However, it was not possible to detect any signal from the same sample of cyclohexane without gold nanoparticles using conventional CARS technique. Therefore, surface enhancement is necessary to achieve higher spectroscopy sensitivity. Further studies of nanostructure-enhanced electrical fields are required to quantitatively understand the observed effects and will be performed in the future.

  17. Broadband coherent anti-Stokes Raman scattering light generation in BBO crystal by using two crossing femtosecond laser pulses.

    Science.gov (United States)

    Liu, Jun; Zhang, Jun; Kobayashi, Takayoshi

    2008-07-01

    As broad as 12000 cm(-1) coherent anti-Stokes Raman scattering (CARS) light from ultraviolet to infrared was generated in a BBO crystal by using two crossing femtosecond laser pulses with 30% conversion efficiency. More than fifteenth-order anti-Stokes and second-order Stokes Raman sidebands were observed with nice Gaussian spatial mode. The effect of the crossing angle between two input beams on the spectrum and emitting angle of the Raman sidebands was studied in detail. Calculation shows that the phase-matching condition determines the frequencies and angles of the sidebands.

  18. Stimulated-emission pumping enabling sub-diffraction-limited spatial resolution in coherent anti-Stokes Raman scattering microscopy

    NARCIS (Netherlands)

    Cleff, C.; Gross, P.; Fallnich, C.; Offerhaus, H.L.; Herek, J.L.; Kruse, K.; Beeker, W.P.; Lee, C.J.; Boller, K-J.

    2013-01-01

    We present a theoretical investigation of stimulated emission pumping to achieve sub-diffraction-limited spatial resolution in coherent anti-Stokes Raman scattering (CARS) microscopy. A pair of control light fields is used to prepopulate the Raman state involved in the CARS process prior to the CARS

  19. Dual-Pump Coherent Anti-Stokes Raman Scattering Temperature and CO2 Concentration Measurements

    Science.gov (United States)

    Lucht, Robert P.; Velur-Natarajan, Viswanathan; Carter, Campbell D.; Grinstead, Keith D., Jr.; Gord, James R.; Danehy, Paul M.; Fiechtner, G. J.; Farrow, Roger L.

    2003-01-01

    Measurements of temperature and CO2 concentration using dual-pump coherent anti-Stokes Raman scattering, (CARS) are described. The measurements were performed in laboratory flames,in a room-temperature gas cell, and on an engine test stand at the U.S. Air Force Research Laboratory, Wright-Patterson Air Force Base. A modeless dye laser, a single-mode Nd:YAG laser, and an unintensified back-illuminated charge-coupled device digital camera were used for these measurements. The CARS measurements were performed on a single-laser-shot basis. The standard deviations of the temperatures and CO2 mole fractions determined from single-shot dual-pump CARS spectra in steady laminar propane/air flames were approximately 2 and 10% of the mean values of approximately 2000 K and 0.10, respectively. The precision and accuracy of single-shot temperature measurements obtained from the nitrogen part of the dual-pump CARS system were investigated in detail in near-adiabatic hydrogen/air/CO2 flames. The precision of the CARS temperature measurements was found to be comparable to the best results reported in the literature for conventional two-laser, single-pump CARS. The application of dual-pump CARS for single-shot measurements in a swirl-stabilized combustor fueled with JP-8 was also demonstrated.

  20. Effect of Scatterering on Coherent Anti-Stokes Raman Scattering (CARS) signals

    CERN Document Server

    Ranasinghesagara, Janaka C; Piazza, Vincenzo; Potma, Eric O; Venugopalan, Vasan

    2016-01-01

    We develop a computational framework to examine the factors responsible for scattering-induced distortions of coherent anti-Stokes Raman scattering (CARS) signals in turbid samples. We use the Huygens-Fresnel Wave-based Electric Field Superposition (HF-WEFS) method combined with the radiating dipole approximation to compute the effects of scattering-induced distortions of focal excitation fields on the far-field CARS signal. We analyze the effect of spherical scatterers, placed in the vicinity of the focal volume, on the CARS signal emitted by different objects (2{\\mu}m diameter solid sphere, 2{\\mu}m diameter myelin cylinder and 2{\\mu}m diameter myelin tube). We find that distortions in the CARS signals arise not only from attenuation of the focal field but also from scattering-induced changes in the spatial phase that modifies the angular distribution of the CARS emission. Our simulations further show that CARS signal attenuation can be minimized by using a high numerical aperture condenser. Moreover, unlike...

  1. Nonequilibrium Supersonic Freestream Studied Using Coherent Anti-Stokes Raman Spectroscopy

    Science.gov (United States)

    Cutler, Andrew D.; Cantu, Luca M.; Gallo, Emanuela C. A.; Baurle, Rob; Danehy, Paul M.; Rockwell, Robert; Goyne, Christopher; McDaniel, Jim

    2015-01-01

    Measurements were conducted at the University of Virginia Supersonic Combustion Facility of the flow in a constant-area duct downstream of a Mach 2 nozzle. The airflow was heated to approximately 1200 K in the facility heater upstream of the nozzle. Dual-pump coherent anti-Stokes Raman spectroscopy was used to measure the rotational and vibrational temperatures of N2 and O2 at two planes in the duct. The expectation was that the vibrational temperature would be in equilibrium, because most scramjet facilities are vitiated air facilities and are in vibrational equilibrium. However, with a flow of clean air, the vibrational temperature of N2 along a streamline remains approximately constant between the measurement plane and the facility heater, the vibrational temperature of O2 in the duct is about 1000 K, and the rotational temperature is consistent with the isentropic flow. The measurements of N2 vibrational temperature enabled cross-stream nonuniformities in the temperature exiting the facility heater to be documented. The measurements are in agreement with computational fluid dynamics models employing separate lumped vibrational and translational/rotational temperatures. Measurements and computations are also reported for a few percent steam addition to the air. The effect of the steam is to bring the flow to thermal equilibrium, also in agreement with the computational fluid dynamics.

  2. Coherent anti-Stokes Raman scattering microscopy of human smooth muscle cells in bioengineered tissue scaffolds

    Science.gov (United States)

    Brackmann, Christian; Esguerra, Maricris; Olausson, Daniel; Delbro, Dick; Krettek, Alexandra; Gatenholm, Paul; Enejder, Annika

    2011-02-01

    The integration of living, human smooth muscle cells in biosynthesized cellulose scaffolds was monitored by nonlinear microscopy toward contractile artificial blood vessels. Combined coherent anti-Stokes Raman scattering (CARS) and second harmonic generation (SHG) microscopy was applied for studies of the cell interaction with the biopolymer network. CARS microscopy probing CH2-groups at 2845 cm-1 permitted three-dimensional imaging of the cells with high contrast for lipid-rich intracellular structures. SHG microscopy visualized the fibers of the cellulose scaffold, together with a small signal obtained from the cytoplasmic myosin of the muscle cells. From the overlay images we conclude a close interaction between cells and cellulose fibers. We followed the cell migration into the three-dimensional structure, illustrating that while the cells submerge into the scaffold they extrude filopodia on top of the surface. A comparison between compact and porous scaffolds reveals a migration depth of porous type shows cells further submerged into the cellulose. Thus, the scaffold architecture determines the degree of cell integration. We conclude that the unique ability of nonlinear microscopy to visualize the three-dimensional composition of living, soft matter makes it an ideal instrument within tissue engineering.

  3. Label-free imaging of human breast tissues using coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Yang, Yaliang; Gao, Liang; Wang, Zhiyong; Thrall, Michael J.; Luo, Pengfei; Wong, Kelvin K.; Wong, Stephen T.

    2011-03-01

    Breast cancer is a common disease in women. Current imaging and diagnostic methods for breast cancer confront several limitations, like time-consuming, invasive and with a high cost. Alternative strategies are in high demand to alleviate patients' trauma and lower medical expenses. Coherent anti-Stokes Raman scattering (CARS) imaging technique offers many advantages, including label-free, sub-wavelength spatial resolution and video-rate imaging speed. Therefore, it has been demonstrated as a powerful tool for various biomedical applications. In this study, we present a label-free fast imaging method to identify breast cancer and its subtypes using CARS microscopy. Human breast tissues, including normal, benign and invasive carcinomas, were imaged ex vivo using a custom-built CARS microscope. Compared with results from corresponding hematoxylin and eosin (H&E) stains, the CARS technique has demonstrated its capability in identifying morphological features in a similar way as in H&E stain. These features can be used to distinguish breast cancer from normal and benign tissues, and further separate cancer subtypes from each other. Our pilot study suggests that CARS microscopy could be used as a routine examination tool to characterize breast cancer ex vivo. Moreover, its label-free and fast imaging properties render this technique as a promising approach for in vivo and real-time imaging and diagnosis of breast cancer.

  4. Femtosecond Coherent Anti-Stokes Raman Scattering Gas Phase Thermometry at 5 kHz

    Science.gov (United States)

    Fineman, Claresta; Lucht, Robert

    2014-05-01

    Understanding the thermal instabilities occurring in turbulent combustion, such as in modern gas turbine combustors, is critical for more reliable and fuel-efficient operation. Non-intrusive laser based spectroscopy methods have been documented as the techniques of choice for turbulent combustion diagnostics. Specifically, femtosecond coherent anti-Stokes Raman scattering (fs-CARS) thermometry has been established for temporal resolution of turbulent fluctuations in flame structure and provides accurate measurements across a wide range of temperatures. Experiments performed to date include 5 kHz pure vibrational N2 chirped probe-pulse fs-CARS thermometry on non-premixed hydrogen jet diffusion flames, methane jet diffusion flames, and the DLR gas turbine model combustor (GTMC). The fs-CARS signal generation process requires precise spatial and temporal overlap of tightly focused pulsed laser beams of less than 100 fs pulse duration. Here, signal loss due to beam steering, pressure fluctuations, or shear layer density gradients can become a problem. The effect of such interferences has been investigated using high velocity flow of compressed nitrogen gas from a converging-diverging nozzle. Resulting changes in fs-CARS spectra have been studied. Funding for this work was provided by the U.S. Department of Energy, Division of Chemical Sciences, Geosciences and Biosciences.

  5. Investigation of porous media combustion by coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Weikl, M. C.; Tedder, S. A.; Seeger, T.; Leipertz, A.

    2010-10-01

    High efficiency, marginal pollutant emissions and low fuel consumption are desirable standards for modern combustion devices. The porous burner technology is a modern type of energy conversion with a strong potential to achieve these standards. However, due to the solid ceramic framework investigation of the thermodynamic properties of combustion, for example temperature, is difficult. The combustion process inside the ceramic structure of a porous burner was experimentally investigated by coherent anti-Stokes Raman spectroscopy (CARS). In this work, we present measurements using dual-pump dual-broadband CARS (DP-DBB-CARS) of temperature and species concentrations inside the reaction and flue gas zone of a porous media burner. Improvements to the setup and data evaluation procedure in contrast to previous measurements are discussed in detail. The results at varied thermal power and stoichiometry are presented. In addition, measurements at a range of radial positions inside a pore are conducted and correlated with the solid structure of the porous foam, which was determined by X-ray computer tomography.

  6. Fast spectral coherent anti-Stokes Raman scattering microscopy with high-speed tunable picosecond laser.

    Science.gov (United States)

    Cahyadi, Harsono; Iwatsuka, Junichi; Minamikawa, Takeo; Niioka, Hirohiko; Araki, Tsutomu; Hashimoto, Mamoru

    2013-09-01

    We develop a coherent anti-Stokes Raman scattering (CARS) microscopy system equipped with a tunable picosecond laser for high-speed wavelength scanning. An acousto-optic tunable filter (AOTF) is integrated in the laser cavity to enable wavelength scanning by varying the radio frequency waves applied to the AOTF crystal. An end mirror attached on a piezoelectric actuator and a pair of parallel plates driven by galvanometer motors are also introduced into the cavity to compensate for changes in the cavity length during wavelength scanning to allow synchronization with another picosecond laser. We demonstrate fast spectral imaging of 3T3-L1 adipocytes every 5  cm-1 in the Raman spectral region around 2850  cm-1 with an image acquisition time of 120 ms. We also demonstrate fast switching of Raman shifts between 2100 and 2850  cm-1, corresponding to CD2 symmetric stretching and CH2 symmetric stretching vibrations, respectively. The fast-switching CARS images reveal different locations of recrystallized deuterated and nondeuterated stearic acid.

  7. Investigation of lipid homeostasis in living Drosophila by coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Chien, Cheng-Hao; Chen, Wei-Wen; Wu, June-Tai; Chang, Ta-Chau

    2012-12-01

    To improve our understanding of lipid metabolism, Drosophila is used as a model animal, and its lipid homeostasis is monitored by coherent anti-Stokes Raman scattering microscopy. We are able to achieve in vivo imaging of larval fat body (analogous to adipose tissue in mammals) and oenocytes (analogous to hepatocytes) in Drosophila larvae at subcellular level without any labeling. By overexpressing two lipid regulatory proteins-Brummer lipase (Bmm) and lipid storage droplet-2 (Lsd-2)-we found different phenotypes and responses under fed and starved conditions. Comparing with the control larva, we observed more lipid droplet accumulation by ˜twofold in oenocytes of fat-body-Bmm-overexpressing (FB-Bmm-overexpressing) mutant under fed condition, and less lipid by ˜fourfold in oenocytes of fat-body-Lsd-2-overexpressing (FB-Lsd-2-overexpressing) mutant under starved condition. Moreover, together with reduced size of lipid droplets, the lipid content in the fat body of FB-Bmm-overexpressing mutant decreases much faster than that of the control and FB-Lsd-2-overexpressing mutant during starvation. From long-term starvation assay, we found FB-Bmm-overexpressing mutant has a shorter lifespan, which can be attributed to faster consumption of lipid in its fat body. Our results demonstrate in vivo observations of direct influences of Bmm and Lsd-2 on lipid homeostasis in Drosophila larvae.

  8. Molecular Orientation in Dry and Hydrated Cellulose Fibers: A Coherent Anti-Stokes Raman Scattering Microscopy Study

    OpenAIRE

    Zimmerley, Maxwell; Younger, Rebecca; Valenton, Tiffany; Oertel, David C.; Ward, Jimmie L.; Potma, Eric O.

    2010-01-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy is combined with spontaneous Raman scattering microspectroscopy and second harmonic generation (SHG) microscopy to interrogate the molecular alignment in dry and hydrated cellulose fibers. Two types of cellulose were investigated: natural cellulose I in cotton fibers and regenerated cellulose II in rayon fibers. On the basis of the orientation of the methylene symmetric stretching vibration, the molecular alignment of cellulose microfibr...

  9. High enhancement factor of Au nano triangular prism structure for surface enhanced coherent anti-Stokes Raman scattering

    Science.gov (United States)

    Zhang, Zuyin; Song, Guofeng

    2017-02-01

    Coherent anti-Stokes Raman scattering spectroscopy (CARS) is a well-known detecting tool in biosensing and nonlinear spectroscopy. It can provide a non-invasive alternative without the need for exogenous labels, while the enhancement factor for surface plasmon resonances (SPR) are extensively used to increase the local field close to the oscillators and which can obtain high enhancement. In this work, we investigate the enhancement factor of our structure for surface-enhanced coherent anti-Stokes Raman scattering. The absorption spectrum of the structure has been studied, a wide range of absorption has been realized. The enhancement can be as high as 10{16} over standard CARS. Our design is very useful for improving the enhancement factor of surface-enhanced coherent anti-Stokes Raman scattering. Project supported by the National Key Research Program of China (No. 2011ZX01015-001) and the National Basic Research Program of China (Nos. 2011CBA00608, 2012CB619203, 2015CB351902, 2015CB932402).

  10. Compact fibre-based coherent anti-Stokes Raman scattering spectroscopy and interferometric coherent anti-Stokes Raman scattering from a single femtosecond fibre-laser oscillator

    Indian Academy of Sciences (India)

    Vikas Kumar; Alessio Gambetta; Cristian Manzoni; Roberta Ramponi; Giulio Cerullo; Marco Marangoni

    2010-12-01

    We demonstrate a new approach to CARS spectroscopy by efficiently synthesizing synchronized narrow-bandwidth (less than 10 cm-1) pump and Stokes pulses (frequency difference continuously tunable upto ∼ 3000 cm-1) based on spectral compression together with second harmonic generation (in periodically-poled nonlinear crystals) of femtosecond pulses emitted by a single compact Er-fibre oscillator. For a far better signal to non-resonant background contrast, interferometric CARS (I-CARS) is demonstrated and CARS signal enhancement upto three orders of magnitude is achieved by constructive interference with an auxiliary local oscillator at anti-Stokes field, also synthesized by spectral compression of pulses emitted from the same fibre oscillator.

  11. Fiber bundle based probe with polarization for coherent anti-Stokes Raman scattering microendoscopy imaging

    Science.gov (United States)

    Liu, Zhengfan; Wang, Zhiyong; Wang, Xi; Xu, Xiaoyun; Chen, Xu; Cheng, Jie; Li, Xiaoyan; Chen, Shufen; Xin, Jianguo; Wong, Stephen T. C.

    2013-02-01

    The ability to visualize cellular structures and tissue molecular signatures in a live body could revolutionize the practice of surgery. Specifically, such technology is promising for replacing tissue extraction biopsy and offering new strategies for a broad range of intraoperative or surgical applications, including early cancer detection, tumor margin identification, nerve damage avoidance, and surgical outcomes enhancement. Coherent anti-Stokes Raman scattering (CARS) microendoscopy offers a way to achieve this with label-free imaging capability and sub-cellular resolution. However, efficient collection of epi-CARS signals and reduction of nonlinear effects in fibers are two major challenges encountered in the development of fiber-based CARS microendoscopy. To circumvent this problem, we designed and developed a fiber bundle for a CARS microendoscopy prototype. The excitation lasers were delivered by a single multimode fiber at the center of the bundle while the epi-CARS signals were collected by multiple MMFs surrounding the central fiber. A polarization scheme was employed to suppress the four-wave mixing (FWM) effect in the excitation fiber. Our experimental results suggest that, with this fiber bundle and the polarization FWM-suppressing scheme, the signal-to-noise ratio of the CARS images was greatly enhanced through a combination of high collection efficiency of epi-CARS signals, isolation of excitation lasers, and suppression of FWM. Tissue imaging capability of the microendoscopy prototype was demonstrated by ex vivo imaging on mouse skin and lung tissues. This fiber bundle-based CARS microendoscopy prototype, with the polarization FWM-suppressing scheme, offers a promising platform for constructing efficient fiber-based CARS microendoscopes for label free intraoperative imaging applications.

  12. Clinical cancer diagnosis using optical fiber-delivered coherent anti-stokes ramon scattering microscopy

    Science.gov (United States)

    Gao, Liang

    This thesis describes the development of a combined label-free imaging and analytical strategy for intraoperative characterization of cancer lesions using the coherent anti-Stokes Raman scattering imaging (CARS) technique. A cell morphology-based analytical platform is developed to characterize CARS images and, hence, provide diagnostic information using disease-related pathology features. This strategy is validated for three different applications, including margin detection for radical prostatectomy, differential diagnosis of lung cancer, as well as detection and differentiation of breast cancer subtypes for in situ analysis of margin status during lumpectomy. As the major contribution of this thesis, the developed analytical strategy shows high accuracy and specificity for all three diseases and thus has introduced the CARS imaging technique into the field of human cancer diagnosis, which holds substantial potential for clinical translations. In addition, I have contributed a project aimed at miniaturizing the CARS imaging device into a microendoscope setup through a fiber-delivery strategy. A four-wave-mixing (FWM) background signal, which is caused by simultaneous delivery of the two CARS-generating excitation laser beams, is initially identified. A polarization-based strategy is then introduced and tested for suppression of this FWM noise. The approach shows effective suppression of the FWM signal, both on microscopic and prototype endoscopic setups, indicating the potential of developing a novel microendoscope with a compatible size for clinical use. These positive results show promise for the development of an all-fiber-based, label-free imaging and analytical platform for minimally invasive detection and diagnosis of cancers during surgery or surgical-biopsy, thus improving surgical outcomes and reducing patients' suffering.

  13. Diagnosing lung cancer using coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Gao, Liang; Yang, Yaliang; Xing, Jiong; Thrall, Michael J.; Wang, Zhiyong; Li, Fuhai; Luo, Pengfei; Wong, Kelvin K.; Zhao, Hong; Wong, Stephen T. C.

    2011-03-01

    Lung carcinoma is the most prevalent type of cancer in the world, and it is responsible for more deaths than other types of cancer. During diagnosis, a pathologist primarily aims to differentiate small cell carcinoma from non-small cell carcinoma on biopsy and cytology specimens, which is time consuming due to the time required for tissue processing and staining. To speed up the diagnostic process, we investigated the feasibility of using coherent anti-Stokes Raman scattering (CARS) microscopy as a label-free strategy to image lung lesions and differentiate subtypes of lung cancers. Different mouse lung cancer models were developed by injecting human lung cancer cell lines, including adenocarcinoma, squamous cell carcinoma, and small cell carcinoma, into lungs of the nude mice. CARS images were acquired from normal lung tissues and different subtypes of cancer lesions ex vivo using intrinsic contrasts from symmetric CH2 bonds. These images showed good correlation with the hematoxylin and eosin (H&E) stained sections from the same tissue samples with regard to cell size, density, and cell-cell distance. These features are routinely used in diagnosing lung lesions. Our results showed that the CARS technique is capable of providing a visualizable platform to differentiate different kinds of lung cancers using the same pathological features without histological staining and thus has the potential to serve as a more efficient examination tool for diagnostic pathology. In addition, incorporating with suitable fiber-optic probes would render the CARS technique as a promising approach for in vivo diagnosis of lung cancer.

  14. Investigation of fiber Bragg grating as a spectral notch shaper for single-pulse coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Oh, Seung Ryeol; Park, Joo Hyun; Kim, Kyung-Soo; Lee, Eun Seong; Lee, Jae Yong; Kim, Soohyun

    2017-01-01

    We experimentally demonstrate compact and efficient single-pulse coherent anti-Stokes Raman spectroscopy (CARS) via spectral notch shaping implemented with a fiber Bragg grating. We show that a fiber Bragg grating can serve as a narrowband notch filtering component on a 90 nm broadband femtosecond pulsed laser without spectral distortion. Finally, we obtain CARS spectra of various samples in the fingerprint region of molecular vibrations. This scheme has potential for compact implementations of all-fiber single-pulse multiplex CARS due to its compatibility with fiber optics.

  15. Detection of chemical interfaces in coherent anti-Stokes Raman scattering microscopy: Dk-CARS. I. Axial interfaces.

    Science.gov (United States)

    Gachet, David; Rigneault, Hervé

    2011-12-01

    We develop a full vectorial theoretical investigation of the chemical interface detection in conventional coherent anti-Stokes Raman scattering (CARS) microscopy. In Part I, we focus on the detection of axial interfaces (i.e., parallel to the optical axis) following a recent experimental demonstration of the concept [Phys. Rev. Lett. 104, 213905 (2010)]. By revisiting the Young's double slit experiment, we show that background-free microscopy and spectroscopy is achievable through the angular analysis of the CARS far-field radiation pattern. This differential CARS in k space (Dk-CARS) technique is interesting for fast detection of interfaces between molecularly different media. It may be adapted to other coherent and resonant scattering processes.

  16. Background-free coherent anti-stokes Raman spectroscopy and microscopy by dual-soliton pulse generation

    CERN Document Server

    Chen, Kun; Wei, Haoyun; Li, Yan

    2016-01-01

    We propose an all-fiber-generated dual-soliton pulses based scheme for the background-free detection of coherent anti-Stokes Raman spectroscopy under the spectral focusing mechanism. Due to the strong birefringence and high nonlinearity of a polarization-maintaining photonic crystal fiber (PM-PCF), two redshifted soliton pulses can be simultaneously generated relying on high-order dispersion and nonlinear effects along two eigenpolarization axes in the anomalous dispersion regime, while allowing feasible tunability of the frequency distance and temporal interval between them. This proposed scheme, termed as DS-CARS, exploits a unique combination of slight frequency-shift and advisable temporal walk-off of this two soliton pulses to achieve robust and efficient suppression of nonresonant background with compact all-fiber coherent excitation source. Capability of the DS-CARS is experimentally demonstrated by the background-free CARS spectroscopy and unambiguous CARS microscopy of polymer beads in the fingerprin...

  17. Raman spectroscopy and coherent anti-Stokes Raman scattering imaging: prospective tools for monitoring skeletal cells and skeletal regeneration

    Science.gov (United States)

    Moura, Catarina Costa; Tare, Rahul S.; Oreffo, Richard O. C.; Mahajan, Sumeet

    2016-01-01

    The use of skeletal stem cells (SSCs) for cell-based therapies is currently one of the most promising areas for skeletal disease treatment and skeletal tissue repair. The ability for controlled modification of SSCs could provide significant therapeutic potential in regenerative medicine, with the prospect to permanently repopulate a host with stem cells and their progeny. Currently, SSC differentiation into the stromal lineages of bone, fat and cartilage is assessed using different approaches that typically require cell fixation or lysis, which are invasive or even destructive. Raman spectroscopy and coherent anti-Stokes Raman scattering (CARS) microscopy present an exciting alternative for studying biological systems in their natural state, without any perturbation. Here we review the applications of Raman spectroscopy and CARS imaging in stem-cell research, and discuss the potential of these two techniques for evaluating SSCs, skeletal tissues and skeletal regeneration as an exemplar. PMID:27170652

  18. Longitudinal in vivo coherent anti-Stokes Raman scattering imaging of demyelination and remyelination in injured spinal cord

    Science.gov (United States)

    Shi, Yunzhou; Zhang, Delong; Huff, Terry B.; Wang, Xiaofei; Shi, Riyi; Xu, Xiao-Ming; Cheng, Ji-Xin

    2011-10-01

    In vivo imaging of white matter is important for the mechanistic understanding of demyelination and evaluation of remyelination therapies. Although white matter can be visualized by a strong coherent anti-Stokes Raman scattering (CARS) signal from axonal myelin, in vivo repetitive CARS imaging of the spinal cord remains a challenge due to complexities induced by the laminectomy surgery. We present a careful experimental design that enabled longitudinal CARS imaging of de- and remyelination at single axon level in live rats. In vivo CARS imaging of secretory phospholipase A2 induced myelin vesiculation, macrophage uptake of myelin debris, and spontaneous remyelination by Schwann cells are sequentially monitored over a 3 week period. Longitudinal visualization of de- and remyelination at a single axon level provides a novel platform for rational design of therapies aimed at promoting myelin plasticity and repair.

  19. Selective excitation of molecular mode in a mixture by femtosecond resonance-enhanced coherent anti-Stokes Raman scattering spectroscopy

    Institute of Scientific and Technical Information of China (English)

    He Ping; Li Si-Ning; Fan Rong-Wei; Li Xiao-Hui; Xia Yuan-Qin; Yu Xin; Chen De-Ying

    2012-01-01

    Femtosecond time-resolved coherent anti-Stokes Raman scattering (CARS) spectroscopy is used to investigate gaseous molecular dynamics.Due to the spectrally broad laser pulses,usually poorly resolved spectra result from this broad spectroscopy.However,it can be demonstrated that by the electronic resonance enhancement optimization control a selective excitation of specific vibrational mode is possible.Using an electronically resonance-enhanced effect,iodine molecule specific CARS spectroscopy can be obtained from a mixture of iodine-air at room temperature and a pressure of 1 atm (corresponding to a saturation iodine vapour as low as about 35 Pa).The dynamics on either the electronically excited state or the ground state of iodine molecules obtained is consistent with previous studies (vacuum,heated and pure iodine) in the femtosecond time resolved CARS spectroscopy,showing that an effective method of suppressing the non-resonant CARS background and other interferences is demonstrated.

  20. Detecting polymeric nanoparticles with coherent anti-stokes Raman scattering microscopy in tissues exhibiting fixative-induced autofluorescence

    Science.gov (United States)

    Garrett, N. L.; Godfrey, L.; Lalatsa, A.; Serrano, D. R.; Uchegbu, I. F.; Schatzlein, A.; Moger, J.

    2015-03-01

    Recent advances in pharmaceutical nanotechnology have enabled the development of nano-particulate medicines with enhanced drug performance. Although the fate of these nano-particles can be macroscopically tracked in the body (e.g. using radio-labeling techniques), there is little information about the sub-cellular scale mechanistic processes underlying the particle-tissue interactions, or how these interactions may correlate with pharmaceutical efficacy. To rationally engineer these nano-particles and thus optimize their performance, these mechanistic interactions must be fully understood. Coherent Anti-Stokes Raman scattering (CARS) microscopy provides a label-free means for visualizing biological samples, but can suffer from a strong non-resonant background in samples that are prepared using aldehyde-based fixatives. We demonstrate how formalin fixative affects the detection of polymeric nanoparticles within kidneys following oral administration using CARS microscopy, compared with samples that were snap-frozen. These findings have implications for clinical applications of CARS for probing nanoparticle distribution in tissue biopsies.

  1. Coherent Anti-Stokes Raman Scattering (CARS) as a Probe for Supersonic Hydrogen-Fuel/Air Mixing

    Science.gov (United States)

    Danehy, P. M.; O'Byrne, S.; Cutler, A. D.; Rodriguez, C. G.

    2003-01-01

    The dual-pump coherent anti-Stokes Raman spectroscopy (CARS) method was used to measure temperature and the absolute mole fractions of N2, O2 and H2 in a supersonic non-reacting fuel-air mixing experiment. Experiments were conducted in NASA Langley Research Center s Direct Connect Supersonic Combustion Test Facility. Under normal operation of this facility, hydrogen and air burn to increase the enthalpy of the test gas and O2 is added to simulate air. This gas is expanded through a Mach 2 nozzle and into a combustor model where fuel is then injected, mixes and burns. In the present experiment the O2 of the test gas is replaced by N2. The lack of oxidizer inhibited combustion of the injected H2 fuel jet allowing the fuel/air mixing process to be studied. CARS measurements were performed 427 mm downstream of the nozzle exit and 260 mm downstream of the fuel injector. Maps were obtained of the mean temperature, as well as the N2, O2 and H2 mean mole fraction fields. A map of mean H2O vapor mole fraction was also inferred from these measurements. Correlations between different measured parameters and their fluctuations are presented. The CARS measurements are compared with a preliminary computational prediction of the flow.

  2. Assessment of liver steatosis and fibrosis in rats using integrated coherent anti-Stokes Raman scattering and multiphoton imaging technique

    Science.gov (United States)

    Lin, Jian; Lu, Fake; Zheng, Wei; Xu, Shuoyu; Tai, Dean; Yu, Hanry; Huang, Zhiwei

    2011-11-01

    We report the implementation of a unique integrated coherent anti-Stokes Raman scattering (CARS), second-harmonic generation (SHG), and two-photon excitation fluorescence (TPEF) microscopy imaging technique developed for label-free monitoring of the progression of liver steatosis and fibrosis generated in a bile duct ligation (BDL) rat model. Among the 21 adult rats used in this study, 18 rats were performed with BDL surgery and sacrificed each week from weeks 1 to 6 (n = 3 per week), respectively; whereas 3 rats as control were sacrificed at week 0. Colocalized imaging of the aggregated hepatic fats, collagen fibrils, and hepatocyte morphologies in liver tissue is realized by using the integrated CARS, SHG, and TPEF technique. The results show that there are significant accumulations of hepatic lipid droplets and collagen fibrils associated with severe hepatocyte necrosis in BDL rat liver as compared to a normal liver tissue. The volume of normal hepatocytes keeps decreasing and the fiber collagen content in BDL rat liver follows a growing trend until week 6; whereas the hepatic fat content reaches a maximum in week 4 and then appears to stop growing in week 6, indicating that liver steatosis and fibrosis induced in a BDL rat liver model may develop at different rates. This work demonstrates that the integrated CARS and multiphoton microscopy imaging technique has the potential to provide an effective means for early diagnosis and detection of liver steatosis and fibrosis without labeling.

  3. Dual/differential coherent anti-Stokes Raman scattering module for multiphoton microscopes with a femtosecond Ti:sapphire oscillator

    Science.gov (United States)

    Li, Bei; Borri, Paola; Langbein, Wolfgang

    2013-06-01

    In the last decade, coherent anti-Stokes Raman scattering (CARS) microscopy has emerged as a powerful multiphoton imaging technique offering label-free chemical sensitivity and high three-dimensional resolution. However, its widespread application in the life sciences has been hampered by the use of costly pulsed lasers, the existence of a nonresonant background requiring involved technical solutions for its efficient suppression, and the limited acquisition speed of multiplex techniques addressing several vibrational resonances, if improved chemical specificity is needed. We have recently reported a differential CARS technique (D-CARS), which simultaneously measures two vibrational frequencies, enhancing the chemical selectivity and sensitivity without introducing costly hardware, while maintaining fast acquisition. In this study, we demonstrate a compact, fully automated, cost-effective module, which integrates on hardware and software level with a commercial multiphoton microscope based on a single 100 fs Ti:Sapphire oscillator and enables D-CARS microscopy in a user-friendly format for applications in the life sciences.

  4. Detection of Lipid-Rich Prostate Circulating Tumour Cells with Coherent Anti-Stokes Raman Scattering Microscopy

    Directory of Open Access Journals (Sweden)

    Mitra Ranjana

    2012-11-01

    Full Text Available Abstract Background Circulating tumour cells (CTC are an important indicator of metastasis and associated with a poor prognosis. Detection sensitivity and specificity of CTC in the peripheral blood of metastatic cancer patient remain a technical challenge. Methods Coherent anti-Stokes Raman scattering (CARS microscopy was employed to examine the lipid content of CTC isolated from the peripheral blood of metastatic prostate cancer patients. CARS microscopy was also employed to evaluate lipid uptake and mobilization kinetics of a metastatic human prostate cancer cell line. Results One hundred CTC from eight metastatic prostate cancer patients exhibited strong CARS signal which arose from intracellular lipid. In contrast, leukocytes exhibited weak CARS signal which arose mostly from cellular membrane. On average, CARS signal intensity of prostate CTC was 7-fold higher than that of leukocytes (P Conclusions Intracellular lipid could serve as a biomarker for prostate CTC which could be sensitively detected with CARS microscopy in a label-free manner. Strong affinity for lipid by metastatic prostate cancer cells could be used to improve detection sensitivity and therapeutic targeting of prostate CTC.

  5. In situ dissolution analysis using coherent anti-Stokes Raman scattering (CARS) and hyperspectral CARS microscopy

    NARCIS (Netherlands)

    Fussell, Andrew; Garbacik, Erik; Offerhaus, Herman; Kleinebudde, Peter; Strachan, Clare

    2013-01-01

    The solid-state form of an active pharmaceutical ingredient (API) in an oral dosage form plays an important role in determining the dissolution rate of the API. As the solid-state form can change during dissolution, there is a need to monitor the oral dosage form during dissolution testing. Coherent

  6. Coherent anti-Stokes Raman spectroscopy in the presence of strong resonant signal from background molecules

    CERN Document Server

    Bitter, Martin

    2012-01-01

    Optical spectroscopy with broadband femtosecond laser pulses often involves simultaneous excitation of multiple molecular species with close resonance frequencies. Interpreting the collective optical response from molecular mixtures typically requires Fourier analysis of the detected time-resolved signal. We propose an alternative method of separating coherent optical responses from two molecular species with neighboring excitation resonances (here, vibrational modes of oxygen and carbon dioxide). We utilize ro-vibrational coupling as a mechanism of suppressing the strong vibrational response from the dominating molecular species (O$_{2}$). Coherent ro-vibrational dynamics lead to long "silence windows" of zero signal from oxygen molecules. In these silence windows, the detected signal stems solely from the minority species (CO$_{2}$) enabling background-free detection and characterization of the O$_2$/CO$_2$ mixing ratio. In comparison to a Fourier analysis, our technique does not require femtosecond time re...

  7. Simultaneous temperature and exhaust-gas recirculation-measurements in a homogeneous charge-compression ignition engine by use of pure rotational coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Weikl, Markus C.; Beyrau, Frank; Leipertz, Alfred

    2006-05-01

    Pure rotational coherent anti-Stokes Raman spectroscopy was used for the simultaneous determination of temperature and exhaust-gas recirculation in a homogeneous charge-compression ignition engine. Measurements were performed in a production-line four-cylinder gasoline engine operated with standard gasoline fuel through small optical line-of-sight accesses. The homogenization process of fresh intake air with recirculated exhaust gas was observed during the compression stroke, and the effect of charge temperature on combustion timing is shown. Single-pulse coherent anti-Stokes Raman spectroscopy spectra could not only be taken in the compression stroke but also during the gas-exchange cycle and after combustion. Consequently, the used method has been shown to be suitable for the investigation of two of the key parameters for self-ignition, namely temperature and charge composition.

  8. Polyglutamine aggregate structure in vitro and in vivo; new avenues for coherent anti-Stokes Raman scattering microscopy.

    Directory of Open Access Journals (Sweden)

    Nicolas M Perney

    Full Text Available Coherent anti-Stokes Raman scattering (CARS microscopy is applied for the first time for the evaluation of the protein secondary structure of polyglutamine (polyQ aggregates in vivo. Our approach demonstrates the potential for translating information about protein structure that has been obtained in vitro by X-ray diffraction into a microscopy technique that allows the same protein structure to be detected in vivo. For these studies, fibres of polyQ containing peptides (D(2Q(15K(2 were assembled in vitro and examined by electron microscopy and X-ray diffraction methods; the fibril structure was shown to be cross β-sheet. The same polyQ fibres were evaluated by Raman spectroscopy and this further confirmed the β-sheet structure, but indicated that the structure is highly rigid, as indicated by the strong Amide I signal at 1659 cm(-1. CARS spectra were simulated using the Raman spectrum taking into account potential non-resonant contributions, providing evidence that the Amide I signal remains strong, but slightly shifted to lower wavenumbers. Combined CARS (1657 cm(-1 and multi-photon fluorescence microscopy of chimeric fusions of yellow fluorescent protein (YFP with polyQ (Q40 expressed in the body wall muscle cells of Caenorhabditis elegans nematodes (1 day old adult hermaphrodites revealed diffuse and foci patterns of Q40-YFP that were both fluorescent and exhibited stronger CARS (1657 cm(-1 signals than in surrounding tissues at the resonance for the cross β-sheet polyQ in vitro.

  9. In vivo lipid saturation study of C. elegans using quantitative broadband coherent anti-Stokes Raman imaging (Conference Presentation)

    Science.gov (United States)

    Littleton, Bradley; Kavanagh, Thomas; Nie, Yu; Abbate, Vincenzo; Hylands, Peter; Sturzenbaum, Stephen; Richards, David

    2016-03-01

    In vivo lipid saturation maps of microscopic nematodes (Caenorhabditis elegans) have been produced using our novel Spectral Interferometric Polarisation Coherent anti-Stokes Raman Scattering (SIP-CARS) imaging technique. This technique employs simple passive polarisation optics and a balanced homodyne detection scheme to exploit symmetries in the CARS polarisation response resulting in the complete cancellation of the non-resonant background (NRB) and real component of the CARS signal (with no prior or post assumptions as regards to their form). The remaining imaginary component of the CARS response is linear with analyte concentration and directly relatable to the spontaneous Raman spectrum [1]. Furthermore, the resonant CARS signal is interferometrically amplified by the non-resonant response, a necessity for rapid imaging at biologically relevant powers [2]. This technique permits acquisition of a broad NRB-free spectrum, in excess of 1800cm-1, in a single exposure at each pixel. This allows simultaneous determination of lipid droplet saturation, from the fingerprint region, and lipid order, from the C-H stretch region from which maps can be readily constructed. Additionally exploiting the dispersive nature of our signal collection two-photon autofluorescence can be isolated and images subsequently produced. We have successfully applied this technique to identify differences in lipid saturation distributions in selective C. elegans mutants and demonstrated that the technique is sufficiently sensitive to detect the effects of lipid metabolism altering drugs on wild type C. elegans. [1] Littleton et al, Phys Rev Lett, 111, 103902 (2013) [2] Parekh et al, Biophys J, 99, 2695-2704 (2010)

  10. Coherent Anti-Stokes Raman Scattering Spectroscopy of Single Molecules in Solution

    Energy Technology Data Exchange (ETDEWEB)

    Sunney Xie, Wei Min, Chris Freudiger, Sijia Lu

    2012-01-18

    During this funding period, we have developed two breakthrough techniques. The first is stimulated Raman scattering microscopy, providing label-free chemical contrast for chemical and biomedical imaging based on vibrational spectroscopy. Spontaneous Raman microscopy provides specific vibrational signatures of chemical bonds, but is often hindered by low sensitivity. We developed a three-dimensional multiphoton vibrational imaging technique based on stimulated Raman scattering (SRS). The sensitivity of SRS imaging is significantly greater than that of spontaneous Raman microscopy, which is achieved by implementing high-frequency (megahertz) phase-sensitive detection. SRS microscopy has a major advantage over previous coherent Raman techniques in that it offers background-free and readily interpretable chemical contrast. We demonstrated a variety of biomedical applications, such as differentiating distributions of omega-3 fatty acids and saturated lipids in living cells, imaging of brain and skin tissues based on intrinsic lipid contrast, and monitoring drug delivery through the epidermis. This technology offers exciting prospect for medical imaging. The second technology we developed is stimulated emission microscopy. Many chromophores, such as haemoglobin and cytochromes, absorb but have undetectable fluorescence because the spontaneous emission is dominated by their fast non-radiative decay. Yet the detection of their absorption is difficult under a microscope. We use stimulated emission, which competes effectively with the nonradiative decay, to make the chromophores detectable, as a new contrast mechanism for optical microscopy. We demonstrate a variety of applications of stimulated emission microscopy, such as visualizing chromoproteins, non-fluorescent variants of the green fluorescent protein, monitoring lacZ gene expression with a chromogenic reporter, mapping transdermal drug distribu- tions without histological sectioning, and label-free microvascular

  11. Recent advances in coherent anti-Stokes Raman scattering spectroscopy: Fundamental developments and applications in reacting flows

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Sukesh [Spectral Energies, LLC, 5100 Springfield Street, Ste. 301, Dayton, OH 45431 (United States); Gord, James R. [Air Force Research Laboratory, Wright-Patterson AFB, OH 45433 (United States); Patnaik, Anil K. [Air Force Research Laboratory, Wright-Patterson AFB, OH 45433 (United States); Department of Physics, Wright State University, Dayton, OH 45435 (United States)

    2010-04-15

    Coherent anti-Stokes Raman scattering (CARS) spectroscopy is widely used for measuring temperature and species concentration in reacting flows. This paper reviews the advances made over the last twelve years in the development and application of CARS spectroscopy in gas-phase reacting flows. The advent of high-power nanosecond (ns) lasers and off-the-shelf compact picosecond (ps) and femtosecond (fs) lasers is enabling the rapid expansion of the application of single-shot or high-bandwidth CARS spectroscopy in a way that would have been quite unimaginable two decades ago. Furthermore, compact ps lasers are paving the way for the development of a fiber-based CARS system for use in harsh environments. The objective of this paper is to provide an overview of recent progresses in ns-, ps-, and fs-CARS spectroscopy for gas-phase thermometry and species-concentration measurements since the second edition of A.C. Eckbreth's book entitled Laser Diagnostics for Combustion Temperature and Species, which was published in 1996. During the last two decades, four encompassing issues have driven the fundamental development and application of CARS spectroscopy in reacting flows: 1) measurement of temperature and concentration of multiple species with one CARS system, 2) extension of the application of traditional ns-CARS to challenging reacting flow environments, 3) performance of nonresonant background-free and collision-free measurements in high-pressure reacting flows, and 4) measurement of temperature and species concentration at high bandwidth, typically 1 kHz or greater, to address the instability and transient phenomena associated with turbulent reacting flows in the combustors and augmentors of modern propulsion systems. This review is focused on identifying and discussing the recent results of gas-phase CARS spectroscopy related to the four issues mentioned above. The feasibility of performing high-bandwidth CARS spectroscopy with one laser beam as well as the

  12. The manipulation of massive ro-vibronic superpositions using time-frequency-resolved coherent anti-Stokes Raman scattering (TFRCARS) from quantum control to quantum computing

    CERN Document Server

    Zadoyan, R; Lidar, D A; Apkarian, V A

    2001-01-01

    Molecular ro-vibronic coherences, joint energy-time distributions of quantum amplitudes, are selectively prepared, manipulated, and imaged in Time-Frequency-Resolved Coherent Anti-Stokes Raman Scattering (TFRCARS) measurements using femtosecond laser pulses. The studies are implemented in iodine vapor, with its thermally occupied statistical ro-vibrational density serving as initial state. The evolution of the massive ro-vibronic superpositions, consisting of 1000 eigenstates, is followed through two-dimensional images. The first- and second-order coherences are captured using time-integrated frequency-resolved CARS, while the third-order coherence is captured using time-gated frequency-resolved CARS. The Fourier filtering provided by time integrated detection projects out single ro-vibronic transitions, while time-gated detection allows the projection of arbitrary ro-vibronic superpositions from the coherent third-order polarization. Beside the control and imaging of chemistry, the controlled manipulation of...

  13. Three-pulse multiplex coherent anti-Stokes/Stokes Raman scattering (CARS/CSRS) microspectroscopy using a white-light laser source

    Science.gov (United States)

    Bito, Kotatsu; Okuno, Masanari; Kano, Hideaki; Leproux, Philippe; Couderc, Vincent; Hamaguchi, Hiro-o.

    2013-06-01

    We have developed a three-pulse non-degenerate multiplex coherent Raman microspectroscopic system using a white-light laser source. The fundamental output (1064 nm) of a Nd:YAG laser is used for the pump radiation with the white-light laser output (1100-1700 nm) for the Stokes radiation to achieve broadband multiplex excitations of vibrational coherences. The second harmonic (532 nm) of the same Nd:YAG laser is used for the probe radiation. Thanks to the large wavelength difference between the pump and probe radiations, coherent anti-Stokes Raman scattering (CARS) and coherent Stokes Raman scattering (CSRS) can be detected simultaneously. Simultaneous detection of CARS and CSRS enables us to obtain information on the electronic resonance effect that affects differently the CARS and CSRS signals. Simultaneous analysis of the CARS and CSRS signals provides us the imaginary part of χ(3) without introducing any arbitrary parameter in the maximum entropy method (MEM).

  14. Hyperspectral imaging and characterization of live cells by broadband coherent anti-Stokes Raman scattering (CARS) microscopy with singular value decomposition (SVD) analysis.

    Science.gov (United States)

    Khmaladze, Alexander; Jasensky, Joshua; Price, Erika; Zhang, Chi; Boughton, Andrew; Han, Xiaofeng; Seeley, Emily; Liu, Xinran; Banaszak Holl, Mark M; Chen, Zhan

    2014-01-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy can be used as a powerful imaging technique to identify chemical compositions of complex samples in biology, biophysics, medicine, and materials science. In this work we developed a CARS microscopic system capable of hyperspectral imaging. By employing an ultrafast laser source, a photonic crystal fiber, and a scanning laser microscope together with spectral detection by a highly sensitive back-illuminated cooled charge-coupled device (CCD) camera, we were able to rapidly acquire and process hyperspectral images of live cells with chemical selectivity. We discuss various aspects of hyperspectral CARS image analysis and demonstrate the use of singular value decomposition methods to characterize the cellular lipid content.

  15. Anti-Stokes effect CCD camera and SLD based optical coherence tomography for full-field imaging in the 1550nm region

    Science.gov (United States)

    Kredzinski, Lukasz; Connelly, Michael J.

    2012-06-01

    Full-field Optical coherence tomography is an en-face interferometric imaging technology capable of carrying out high resolution cross-sectional imaging of the internal microstructure of an examined specimen in a non-invasive manner. The presented system is based on competitively priced optical components available at the main optical communications band located in the 1550 nm region. It consists of a superluminescent diode and an anti-stokes imaging device. The single mode fibre coupled SLD was connected to a multi-mode fibre inserted into a mode scrambler to obtain spatially incoherent illumination, suitable for OCT wide-field modality in terms of crosstalk suppression and image enhancement. This relatively inexpensive system with moderate resolution of approximately 24um x 12um (axial x lateral) was constructed to perform a 3D cross sectional imaging of a human tooth. To our knowledge this is the first 1550 nm full-field OCT system reported.

  16. Ab initio study of coherent anti-Stokes Raman scattering (CARS) of the 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) explosive

    Science.gov (United States)

    Mohammed, Abdelsalam; Ågren, Hans; Thorvaldsen, Andreas J.; Ruud, Kenneth

    2010-01-01

    Coherent anti-Stokes Raman scattering (CARS) of the 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) C 3H 6N 6O 6 molecule is studied by ab initio methods. The results are compared to available experimental observations and against calculations and experimental observations of the conventional non-resonant Raman spectrum for RDX. It is found that all intense bands in the observed CARS spectrum and all Raman differential cross sections are well reproduced by the calculations. The features of the resonant CARS signal vary strongly from the corresponding Raman signal, and are obtained with a considerably larger cross section, a fact that could further facilitate the use of CARS spectroscopy in applications of stand-off detection of gaseous samples at ultra-low concentrations.

  17. In planta imaging of Δ⁹-tetrahydrocannabinolic acid in Cannabis sativa L. with hyperspectral coherent anti-Stokes Raman scattering microscopy.

    Science.gov (United States)

    Garbacik, Erik T; Korai, Roza P; Frater, Eric H; Korterik, Jeroen P; Otto, Cees; Offerhaus, Herman L

    2013-04-01

    Nature has developed many pathways to produce medicinal products of extraordinary potency and specificity with significantly higher efficiencies than current synthetic methods can achieve. Identification of these mechanisms and their precise locations within plants could substantially increase the yield of a number of natural pharmaceutics. We report label-free imaging of Δ⁹-tetrahydrocannabinolic acid (THCa) in Cannabis sativa L. using coherent anti-Stokes Raman scattering microscopy. In line with previous observations we find high concentrations of THCa in pistillate flowering bodies and relatively low amounts within flowering bracts. Surprisingly, we find differences in the local morphologies of the THCa-containing bodies: organelles within bracts are large, diffuse, and spheroidal, whereas in pistillate flowers they are generally compact, dense, and have heterogeneous structures. We have also identified two distinct vibrational signatures associated with THCa, both in pure crystalline form and within Cannabis plants; at present the exact natures of these spectra remain an open question.

  18. Investigation of protein distribution in solid lipid particles and its impact on protein release using coherent anti-Stokes Raman scattering microscopy

    DEFF Research Database (Denmark)

    Christophersen, Philip C.; Birch, Ditlev; Saarinen, Jukka

    2015-01-01

    The aim of this study was to gain new insights into protein distribution in solid lipid microparticles (SLMs) and subsequent release mechanisms using a novel label-free chemical imaging method, coherent anti-Stokes Raman scattering (CARS) microscopy. Lysozyme-loaded SLMs were prepared using...... different lipids with lysozyme incorporated either as an aqueous solution or as a solid powder. Lysozyme distribution in SLMs was investigated using CARS microscopy with supportive structural analysis using electron microscopy. The release of lysozyme from SLMs was investigated in a medium simulating......-destructive method for elucidating the distribution of lysozyme in SLMs. The interpretation of protein distribution and release during lipolysis enabled elucidation of protein release mechanisms. In future, CARS microscopy analysis could facilitate development of a wide range of protein-lipid matrices with tailor...

  19. In planta imaging of Δ9-tetrahydrocannabinolic acid in Cannabis sativa L. with hyperspectral coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Garbacik, Erik T.; Korai, Roza P.; Frater, Eric H.; Korterik, Jeroen P.; Otto, Cees; Offerhaus, Herman L.

    2013-04-01

    Nature has developed many pathways to produce medicinal products of extraordinary potency and specificity with significantly higher efficiencies than current synthetic methods can achieve. Identification of these mechanisms and their precise locations within plants could substantially increase the yield of a number of natural pharmaceutics. We report label-free imaging of Δ9-tetrahydrocannabinolic acid (THCa) in Cannabis sativa L. using coherent anti-Stokes Raman scattering microscopy. In line with previous observations we find high concentrations of THCa in pistillate flowering bodies and relatively low amounts within flowering bracts. Surprisingly, we find differences in the local morphologies of the THCa-containing bodies: organelles within bracts are large, diffuse, and spheroidal, whereas in pistillate flowers they are generally compact, dense, and have heterogeneous structures. We have also identified two distinct vibrational signatures associated with THCa, both in pure crystalline form and within Cannabis plants; at present the exact natures of these spectra remain an open question.

  20. Three-pulse multiplex coherent anti-Stokes/Stokes Raman scattering (CARS/CSRS) microspectroscopy using a white-light laser source

    Energy Technology Data Exchange (ETDEWEB)

    Bito, Kotatsu [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Analytical Science Research Laboratories, Kao Corporation, 2606 Akabane, Ichikai-Machi, Haga-Gun, Tochigi 321-3497 (Japan); Okuno, Masanari [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kano, Hideaki [Institute of Applied Physics, University of Tsukuba, 1-1-1 Tenodai, Tsukuba, Ibaraki 305-8573 (Japan); Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Leproux, Philippe [Institut de Recherche XLIM, UMR CNRS No. 7252, 123 Avenue Albert Thomas, 87060 Limoges Cedex (France); LEUKOS, ESTER Technopole, 1 Avenue d’Ester, 87069 Limoges Cedex (France); Couderc, Vincent [Institut de Recherche XLIM, UMR CNRS No. 7252, 123 Avenue Albert Thomas, 87060 Limoges Cedex (France); Hamaguchi, Hiro-o, E-mail: hhama@nctu.edu.tw [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Institute of Molecular Science and Department of Applied Chemistry, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 300, Taiwan (China)

    2013-06-20

    Highlights: ► We have developed a simultaneous measurement system of CARS and CSRS. ► We can obtain information on the electronic resonance effect with the measurement. ► The simultaneous measurement provides us with more reliable spectral information. - Abstract: We have developed a three-pulse non-degenerate multiplex coherent Raman microspectroscopic system using a white-light laser source. The fundamental output (1064 nm) of a Nd:YAG laser is used for the pump radiation with the white-light laser output (1100–1700 nm) for the Stokes radiation to achieve broadband multiplex excitations of vibrational coherences. The second harmonic (532 nm) of the same Nd:YAG laser is used for the probe radiation. Thanks to the large wavelength difference between the pump and probe radiations, coherent anti-Stokes Raman scattering (CARS) and coherent Stokes Raman scattering (CSRS) can be detected simultaneously. Simultaneous detection of CARS and CSRS enables us to obtain information on the electronic resonance effect that affects differently the CARS and CSRS signals. Simultaneous analysis of the CARS and CSRS signals provides us the imaginary part of χ{sup (3)} without introducing any arbitrary parameter in the maximum entropy method (MEM)

  1. What are the intensities and line-shapes of the twenty four polarization terms in coherent anti-Stokes Raman spectroscopy?

    Directory of Open Access Journals (Sweden)

    Kai Niu

    2015-12-01

    Full Text Available Coherent anti-Stokes Raman spectroscopy (CARS is conventionally described by just one diagram/term where the three electric field interactions act on the ket side in a Feynman dual time-line diagram in a specific time order of pump, Stokes and probe pulses. In theory, however, any third-order nonlinear spectroscopy with three different electric fields interacting with a molecule can be described by forty eight diagrams/terms. They reduce to just 24 diagrams/terms if we treat the time ordering of the electric field interactions on the ket independently of those on the bra, i.e. the ket and bra wave packets evolve independently. The twenty four polarization terms can be calculated in the multidimensional, separable harmonic oscillator model to obtain the intensities and line-shapes. It is shown that in fs/ps CARS, for the two cases of off-resonance CARS in toluene and resonance CARS in rhodamine 6G, where we use a fs pump pulse, a fs Stokes pulse and a ps probe pulse, we obtain sharp vibrational lines in four of the polarization terms where the pump and Stokes pulses can create a vibrational coherence on the ground electronic state, while the spectral line-shapes of the other twenty terms are broad and featureless. The conventional CARS term with sharp vibrational lines is the dominant term, with intensity at least one order of magnitude larger than the other terms.

  2. What are the intensities and line-shapes of the twenty four polarization terms in coherent anti-Stokes Raman spectroscopy?

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Kai [School of Science, Tianjin University of Technology and Education, Tianjin, 300222 (China); Lee, Soo-Y., E-mail: sooying@ntu.edu.sg [Division of Physics & Applied Physics, and Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)

    2015-12-15

    Coherent anti-Stokes Raman spectroscopy (CARS) is conventionally described by just one diagram/term where the three electric field interactions act on the ket side in a Feynman dual time-line diagram in a specific time order of pump, Stokes and probe pulses. In theory, however, any third-order nonlinear spectroscopy with three different electric fields interacting with a molecule can be described by forty eight diagrams/terms. They reduce to just 24 diagrams/terms if we treat the time ordering of the electric field interactions on the ket independently of those on the bra, i.e. the ket and bra wave packets evolve independently. The twenty four polarization terms can be calculated in the multidimensional, separable harmonic oscillator model to obtain the intensities and line-shapes. It is shown that in fs/ps CARS, for the two cases of off-resonance CARS in toluene and resonance CARS in rhodamine 6G, where we use a fs pump pulse, a fs Stokes pulse and a ps probe pulse, we obtain sharp vibrational lines in four of the polarization terms where the pump and Stokes pulses can create a vibrational coherence on the ground electronic state, while the spectral line-shapes of the other twenty terms are broad and featureless. The conventional CARS term with sharp vibrational lines is the dominant term, with intensity at least one order of magnitude larger than the other terms.

  3. Label-free assessment of adipose-derived stem cell differentiation using coherent anti-Stokes Raman scattering and multiphoton microscopy

    Science.gov (United States)

    Mouras, Rabah; Bagnaninchi, Pierre O.; Downes, Andrew R.; Elfick, Alistair P. D.

    2012-11-01

    Adult stem cells (SCs) hold great potential as likely candidates for disease therapy but also as sources of differentiated human cells in vitro models of disease. In both cases, the label-free assessment of SC differentiation state is highly desirable, either as a quality-control technology ensuring cells to be used clinically are of the desired lineage or to facilitate in vitro time-course studies of cell differentiation. We investigate the potential of nonlinear optical microscopy as a minimally invasive technology to monitor the differentiation of adipose-derived stem cells (ADSCs) into adipocytes and osteoblasts. The induction of ADSCs toward these two different cell lineages was monitored simultaneously using coherent anti-Stokes Raman scattering, two photon excitation fluorescence (TPEF), and second harmonic generation at different time points. Changes in the cell's morphology, together with the appearance of biochemical markers of cell maturity were observed, such as lipid droplet accumulation for adipo-induced cells and the formation of extra-cellular matrix for osteo-induced cells. In addition, TPEF of flavoproteins was identified as a proxy for changes in cell metabolism that occurred throughout ADSC differentiation toward both osteoblasts and adipocytes. These results indicate that multimodal microscopy has significant potential as an enabling technology for the label-free investigation of SC differentiation.

  4. Multimodal coherent anti-Stokes Raman scattering microscopy reveals microglia-associated myelin and axonal dysfunction in multiple sclerosis-like lesions in mice

    Science.gov (United States)

    Imitola, Jaime; Côté, Daniel; Rasmussen, Stine; Xie, X. Sunney; Liu, Yingru; Chitnis, Tanuja; Sidman, Richard L.; Lin, Charles. P.; Khoury, Samia J.

    2011-02-01

    Myelin loss and axonal degeneration predominate in many neurological disorders; however, methods to visualize them simultaneously in live tissue are unavailable. We describe a new imaging strategy combining video rate reflectance and fluorescence confocal imaging with coherent anti-Stokes Raman scattering (CARS) microscopy tuned to CH2 vibration of myelin lipids, applied in live tissue of animals with chronic experimental autoimmune encephalomyelitis (EAE). Our method allows monitoring over time of demyelination and neurodegeneration in brain slices with high spatial resolution and signal-to-noise ratio. Local areas of severe loss of lipid signal indicative of demyelination and loss of the reflectance signal from axons were seen in the corpus callosum and spinal cord of EAE animals. Even in myelinated areas of EAE mice, the intensity of myelin lipid signals is significantly reduced. Using heterozygous knock-in mice in which green fluorescent protein replaces the CX3CR1 coding sequence that labels central nervous system microglia, we find areas of activated microglia colocalized with areas of altered reflectance and CARS signals reflecting axonal injury and demyelination. Our data demonstrate the use of multimodal CARS microscopy for characterization of demyelinating and neurodegenerative pathology in a mouse model of multiple sclerosis, and further confirm the critical role of microglia in chronic inflammatory neurodegeneration.

  5. Longitudinal, 3D in vivo imaging of sebaceous glands by coherent anti-Stokes Raman scattering microscopy –normal function and response to cryotherapy

    Science.gov (United States)

    Jung, Yookyung; Tam, Joshua; Jalian, H. Ray; Anderson, R. Rox; Evans, Conor L.

    2014-01-01

    Sebaceous glands perform complex functions, and are centrally involved in the pathogenesis of acne vulgaris. Current techniques for studying sebaceous glands are mostly static in nature, whereas the gland’s main function – excretion of sebum via the holocrine mechanism – can only be evaluated over time. We present a longitudinal, real-time alternative – the in vivo, label-free imaging of sebaceous glands using Coherent Anti-Stokes Raman Scattering (CARS) microscopy, which is used to selectively visualize lipids. In mouse ears, CARS microscopy revealed dynamic changes in sebaceous glands during the holocrine secretion process, as well as in response to damage to the glands caused by cooling. Detailed gland structure, plus the active migration of individual sebocytes and cohorts of sebocytes were measured. Cooling produced characteristic changes in sebocyte structure and migration. This study demonstrates that CARS microscopy is a promising tool for studying the sebaceous gland and its associated disorders in three-dimensions in vivo. PMID:25026458

  6. Measurement of vibrationally excited N2(v) in an atmospheric-pressure air pulsed corona discharge using coherent anti-Stokes Raman scattering

    Science.gov (United States)

    Teramoto, Yoshiyuki; Ono, Ryo

    2014-08-01

    Vibrationally excited N2(v = 1, 2) in an atmospheric-pressure air pulsed corona discharge was measured using coherent anti-Stokes Raman scattering (CARS). In a dry air discharge, the vibrational temperature determined from the ratio N2(v = 2)/N2(v = 0), Tv2, was approximately 500 K higher than that determined from N2(v = 1)/N2(v = 0), Tv1, immediately after the discharge pulse. Both vibrational temperatures reached equilibrium within 100 μs after the discharge pulse by the vibration-to-vibration (V-V) process of N2-N2. The translational temperature was also measured using CARS. The rise in the translational temperature due to vibration-to-translation (V-T) energy transfer was not observed for a postdischarge time of 5 μs-1 ms in the dry-air discharge. However, when the air was humidified, a significant V-T energy transfer was observed. It was due to an extremely rapid V-T process of H2O-H2O following the V-V process of N2-H2O. Measurements showed that the humidification of the ambient air accelerated the decrease in the N2 vibrational temperature and increased the translational temperature. N2(v) was generated mostly in the secondary streamer, not in the primary one, according to estimation from the measured N2(v) density.

  7. Lipid droplet pattern and nondroplet-like structure in two fat mutants of Caenorhabditis elegans revealed by coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Yi, Yung-Hsiang; Chien, Cheng-Hao; Chen, Wei-Wen; Ma, Tian-Hsiang; Liu, Kuan-Yu; Chang, Yu-Sun; Chang, Ta-Chau; Lo, Szecheng J.

    2014-01-01

    Lipid is an important energy source and essential component for plasma and organelle membranes in all kinds of cells. Coherent anti-Stokes Raman scattering (CARS) microscopy is a label-free and nonlinear optical technique that can be used to monitor the lipid distribution in live organisms. Here, we utilize CARS microscopy to investigate the pattern of lipid droplets in two live Caenorhabditis elegans mutants (fat-2 and fat-3). The CARS images showed a striking decrease in the size, number, and content of lipid droplets in the fat-2 mutant but a slight difference in the fat-3 mutant as compared with the wild-type worm. Moreover, a nondroplet-like structure with enhanced CARS signal was detected for the first time in the uterus of fat-2 and fat-3 mutants. In addition, transgenic fat-2 mutant expressing a GFP fusion protein of vitellogenin-2 (a yolk lipoprotein) revealed that the enhanced CARS signal colocalized with the GFP signal, which suggests that the nondroplet-like structure is primarily due to the accumulation of yolk lipoproteins. Together, this study implies that CARS microscopy is a potential tool to study the distribution of yolk lipoproteins, in addition to lipid droplets, in live animals.

  8. Picosecond anti-Stokes generation in a photonic-crystal fiber for interferometric CARS microscopy.

    Science.gov (United States)

    Andresen, Esben Ravn; Keiding, Søren Rud; Potma, Eric Olaf

    2006-08-07

    We generate tunable picosecond anti-Stokes pulses by four-wave mixing of two picosecond pump and Stokes pulse trains in a photonic-crystal fiber. The visible, spectrally narrow anti-Stokes pulses with shifts over 150 nm are generated without generating other spectral features. As a demonstration, we employ the generated anti-Stokes pulses as reference pulses in an interferometric coherent anti-Stokes Raman scattering imaging experiment showing that interpulse coherence among the pump, Stokes and anti-Stokes beams is retained.

  9. Nanosecond retinal structure changes in K-590 during the room-temperature bacteriorhodopsin photocycle: picosecond time-resolved coherent anti-stokes Raman spectroscopy.

    Science.gov (United States)

    Weidlich, O; Ujj, L; Jäger, F; Atkinson, G H

    1997-01-01

    Time-resolved vibrational spectra are used to elucidate the structural changes in the retinal chromophore within the K-590 intermediate that precedes the formation of the L-550 intermediate in the room-temperature (RT) bacteriorhodopsin (BR) photocycle. Measured by picosecond time-resolved coherent anti-Stokes Raman scattering (PTR/CARS), these vibrational data are recorded within the 750 cm-1 to 1720 cm-1 spectral region and with time delays of 50-260 ns after the RT/BR photocycle is optically initiated by pulsed (< 3 ps, 1.75 nJ) excitation. Although K-590 remains structurally unchanged throughout the 50-ps to 1-ns time interval, distinct structural changes do appear over the 1-ns to 260-ns period. Specifically, comparisons of the 50-ps PTR/CARS spectra with those recorded with time delays of 1 ns to 260 ns reveal 1) three types of changes in the hydrogen-out-of-plane (HOOP) region: the appearance of a strong, new feature at 984 cm-1; intensity decreases for the bands at 957 cm-1, 952 cm-1, and 939 cm-1; and small changes intensity and/or frequency of bands at 855 cm-1 and 805 cm-1; and 2) two types of changes in the C-C stretching region: the intensity increase in the band at 1196 cm-1 and small intensity changes and/or frequency shifts for bands at 1300 cm-1 and 1362 cm-1. No changes are observed in the C = C stretching region, and no bands assignable to the Schiff base stretching mode (C = NH+) mode are found in any of the PTR/CARS spectra assignable to K-590. These PTR/CARS data are used, together with vibrational mode assignments derived from previous work, to characterize the retinal structural changes in K-590 as it evolves from its 3.5-ps formation (ps/K-590) through the nanosecond time regime (ns/K-590) that precedes the formation of L-550. The PTR/CARS data suggest that changes in the torsional modes near the C14-C15 = N bonds are directly associated with the appearance of ns/K-590, and perhaps with the KL intermediate proposed in earlier studies. These

  10. Three-pulse multiplex coherent anti-Stokes/Stokes Raman scattering (CARS/CSRS) microspectroscopy using a white-light laser source

    OpenAIRE

    Bito, Kotatsu; Okuno, Masanari; Kano, Hideaki; LEPROUX, Philippe; Couderc, Vincent; Hamaguchi, Hiro-o

    2013-01-01

    We have developed a three-pulse non-degenerate multiplex coherent Raman microspectroscopic system using a white-light laser source. The fundamental output (1064 nm) of a Nd:YAG laser is used for the pump radiation with the white-light laser output (1100–1700 nm) for the Stokes radiation to achieve broadband multiplex excitations of vibrational coherences. The second harmonic (532 nm) of the same Nd:YAG laser is used for the probe radiation. Thanks to the large wavelength difference between th...

  11. Coherent hybrid electromagnetic field imaging

    Science.gov (United States)

    Cooke, Bradly J.; Guenther, David C.

    2008-08-26

    An apparatus and corresponding method for coherent hybrid electromagnetic field imaging of a target, where an energy source is used to generate a propagating electromagnetic beam, an electromagnetic beam splitting means to split the beam into two or more coherently matched beams of about equal amplitude, and where the spatial and temporal self-coherence between each two or more coherently matched beams is preserved. Two or more differential modulation means are employed to modulate each two or more coherently matched beams with a time-varying polarization, frequency, phase, and amplitude signal. An electromagnetic beam combining means is used to coherently combine said two or more coherently matched beams into a coherent electromagnetic beam. One or more electromagnetic beam controlling means are used for collimating, guiding, or focusing the coherent electromagnetic beam. One or more apertures are used for transmitting and receiving the coherent electromagnetic beam to and from the target. A receiver is used that is capable of square-law detection of the coherent electromagnetic beam. A waveform generator is used that is capable of generation and control of time-varying polarization, frequency, phase, or amplitude modulation waveforms and sequences. A means of synchronizing time varying waveform is used between the energy source and the receiver. Finally, a means of displaying the images created by the interaction of the coherent electromagnetic beam with target is employed.

  12. Collinear and noncollinear emission of anti-stokes and second order stokes Raman radiation

    Science.gov (United States)

    Aussenegg, F. R.; Lippitsch, M. E.; Brandmüller, J.; Nitsch, W.

    1981-04-01

    Generating higher order stimulated Raman scattering in benzene, apart from phase-matched anti-Stokes radiation a collinear anti-Stokes emission is observed, which is explained by parametric four-photon processes under mismatch condition.

  13. Coherent anti-Stokes Raman scattering microscopy of single nanodiamonds

    OpenAIRE

    Pope, Iestyn; Payne, Lukas; Zoriniants, George; Thomas, Evan L. H.; Williams, Oliver Aneurin; Watson, Peter Duncan; Langbein, Wolfgang Werner; Borri, Paola

    2014-01-01

    Nanoparticles have attracted enormous attention for biomedical applications as optical labels, drug-delivery vehicles and contrast agents in vivo. In the quest for superior photostability and biocompatibility, nanodiamonds are considered one of the best choices due to their unique structural, chemical, mechanical and optical properties. So far, mainly fluorescent nanodiamonds have been utilized for cell imaging. However, their use is limited by the efficiency and costs in reliably producing f...

  14. 在Na2(A1∑_u+)与H2碰撞中的相干反斯托克斯拉曼谱研究%Coherent Anti-Stokes Raman Spectroscopy Study in the Na2(A1∑_u~+)-H2 Collision

    Institute of Scientific and Technical Information of China (English)

    蔡勤; 张利平; 栾楠楠; 程玉锋; 戴康; 沈异凡

    2011-01-01

    Coherent anti-Stokes Raman spectroscopy (CARS) has been used to analyze the internal state distribution of H2 after energy transfer with Na2 (A1 S,f ). The scanned CARS reveals that during energy transfer processes H2 molecules are produced at the V=l, 2 and 3 vibrational levels. Two possible populations ratios (w,/ra2) are obtained from scanned CARS peaks. The actual population ratio Hi/n2 is determined to be 1. 82 through shape simulations of the time resolved CARS profiles under a kinetic model. The n,/n2 ratio indicates that the H2 molecules produced by the energy transfer process are 0.53 populated at the V=l level, 0.30 at V=2 and 0.17 at V=3. The relative fraction (, ) of average energy disposal is derived as 0.51, 0.46, 0.03, which has a major energy releases in vibrational and translational. This consequence supports the col linear collision geometry in ratio Na2-H2 energy transfer.%利用相干反斯托克斯拉曼谱(CARS)分析了H:在与Na2(A1∑_u~+)碰撞后的振转态布居数分布.扫描CARS表明了在能量转移过程中H:在V=1,2,3振动能级上得到布居.由扫描CARS的峰值得到2个可能的布居数比值,通过解速率方程组及时间分辨CARS轮廓模拟,确定实际的布居数比n1//n2为1.82,得到了在能量转移中H2在V=1,2,3振动能级上的布居数之比为0.53:0.30:0.17.平均转移能量分配的相对值,,分别为0.51,0.46,0.03,能量主要配置在振动和平动上,支持Na2-H2的直线式碰撞传能机制.

  15. Picosecond anti-Stokes generation in a photonic-crystal fiber for interferometric CARS microscopy

    DEFF Research Database (Denmark)

    Andresen, Esben Ravn

    2006-01-01

    We generate tunable picosecond anti-Stokes pulses by four-wave mixing of two picosecond pump and Stokes pulse trains in a photonic-crystal fiber. The visible, spectrally narrow anti-Stokes pulses with shifts over 150 nm are generated without generating other spectral features. As a demonstration...

  16. Competition between two types of anti-Stokes emission in Ho(3+)-activated ZBLAN glass.

    Science.gov (United States)

    Koepke, Cz; Wisniewski, K; Piatkowski, D; Malinowski, M

    2009-01-21

    A competition between two anti-Stokes emissions has been observed and interpreted in ZBLAN glass activated by Ho(3+) ions. The first anti-Stokes emission intensity was seen to increase with temperature, whereas another, upconverted emission, was seen to decrease under the same conditions. Both observed tendencies are believed to be caused by the same effect: the multiphonon anti-Stokes excitation of the state responsible for the first emission. Analysis of the kinetics and fits of the theoretical model to experimental data are presented.

  17. Competition between two types of anti-Stokes emission in Ho3+-activated ZBLAN glass

    Science.gov (United States)

    Koepke, Cz; Wisniewski, K.; Piatkowski, D.; Malinowski, M.

    2009-01-01

    A competition between two anti-Stokes emissions has been observed and interpreted in ZBLAN glass activated by Ho3+ ions. The first anti-Stokes emission intensity was seen to increase with temperature, whereas another, upconverted emission, was seen to decrease under the same conditions. Both observed tendencies are believed to be caused by the same effect: the multiphonon anti-Stokes excitation of the state responsible for the first emission. Analysis of the kinetics and fits of the theoretical model to experimental data are presented.

  18. Generation of Anti-Stokes Line in Fundamental Mode of Photonic Crystal Fibre

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; HOU Lan-Tian; LIU Zhao-Lun; ZHOU Gui-Yao

    2008-01-01

    A photonic crystal fibre (PCF) with zero-dispersion wavelength around 800 nm is designed and fabricated. Simulated results show that the zero-dispersion wavelength of fundamental mode for this PCF is at 826 nm, and phase-matched four-wave mixing can be achieved in fundamental mode. Using 20Ofs Ti:sapphire laser with central wavelength at 810nm as pump, the anti-Stokes line around 610nm is generated efficiently. The output signal has a Gaussian-like profile, which indicates that the anti-Stokes signal is in the fundamental mode of the PCF. The energy of anti-Stokes signal is higher than that of residual pump laser and the maximum ratio of the anti-Stokes signal to the pump component in the output spectrum is estimated to be 1.2.

  19. Near-infrared anti-Stokes photoluminescence of PbS QDs embedded in glasses.

    Science.gov (United States)

    Xiong, Yuda; Liu, Chao; Wang, Jing; Han, Jianjun; Zhao, Xiujian

    2017-03-20

    Near-infrared photoluminescence properties of PbS QDs embedded in glasses were investigated upon below-bandgap excitation. PbS QDs were precipitated in the glasses upon thermal treatment. Near-infrared anti-Stokes photoluminescence (ASPL) from PbS QDs was observed. Dependence of the ASPL on size and excitation power indicated that ASPL was phonon-assisted one-photon process. These near-infrared anti-Stokes photoluminescence of PbS QDs in glasses have potential applications for light conversion and laser cooling.

  20. Observation of anomalous Stokes versus anti-Stokes ratio in MoTe2 atomic layers

    Science.gov (United States)

    Goldstein, Thomas; Chen, Shao-Yu; Xiao, Di; Ramasubramaniam, Ashwin; Yan, Jun

    We grow hexagonal molybdenum ditelluride (MoTe2), a prototypical transition metal dichalcogenide (TMDC) semiconductor, with chemical vapor transport methods and investigate its atomic layers with Stokes and anti-Stokes Raman scattering. We report observation of all six types of zone center optical phonons. Quite remarkably, the anti-Stokes Raman intensity of the low energy layer-breathing mode becomes more intense than the Stokes peak under certain experimental conditions, creating an illusion of 'negative temperature'. This effect is tunable, and can be switched from anti-Stokes enhancement to suppression by varying the excitation wavelength. We interpret this observation to be a result of resonance effects arising from the C excitons in the vicinity of the Brillouin zone center, which are robust even for multiple layers of MoTe2. The intense anti-Stokes Raman scattering provides a cooling channel for the crystal and opens up opportunities for laser cooling of atomically thin TMDC semiconductor devices. Supported by the University of Massachusetts Amherst, the National Science Foundation Center for Hierarchical Manufacturing (CMMI-1025020) and Office of Emerging Frontiers in Research and Innovation (EFRI-1433496).

  1. Stokes and anti-stokes stimulated Mie scattering on nanoparticle suspensions of latex

    Science.gov (United States)

    Burkhanov, I. S.; Krivokhizha, S. V.; Chaikov, L. L.

    2016-12-01

    Stokes and anti-Stokes shifts of stimulated concentration light scattering (SCLS, stimulated Mie scattering) in suspensions of various-sized latex nanoparticles in water were measured by the light guide scheme, under conditions of backscattering in the presence of convection.

  2. Competition between two types of anti-Stokes emission in Ho{sup 3+}-activated ZBLAN glass

    Energy Technology Data Exchange (ETDEWEB)

    Koepke, Cz; Wisniewski, K; Piatkowski, D [Institute of Physics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland); Malinowski, M [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland)], E-mail: koepke@fizyka.umk.pl

    2009-01-21

    A competition between two anti-Stokes emissions has been observed and interpreted in ZBLAN glass activated by Ho{sup 3+} ions. The first anti-Stokes emission intensity was seen to increase with temperature, whereas another, upconverted emission, was seen to decrease under the same conditions. Both observed tendencies are believed to be caused by the same effect: the multiphonon anti-Stokes excitation of the state responsible for the first emission. Analysis of the kinetics and fits of the theoretical model to experimental data are presented.

  3. Characteristics of intermediate state related to anti-Stokes luminescence of ZnO single crystals

    Science.gov (United States)

    Fujii, Katsushi; Goto, Takenari; Yao, Takafumi

    2014-06-01

    Anti-Stokes luminescence from ZnO is supposed to be a two-step two-photon absorption process with an intermediate state. The intermediate state is assumed to be a localized state with two different excited and relaxed states. One of the localized states is believed to be the well-known 2.4 eV green luminescence; the other is difficult to observe experimentally. We found an interesting 2.25 eV deep luminescence from ZnO, which has been shown to relate to anti-Stokes luminescence. The 2.25 eV yellow luminescence was observable only below the band gap excitation and through a time-resolved observation after the excitation light was turned off. The intermediate states were found to be a photo-excited donor-acceptor pair and its lattice relaxation state. The characteristics and the role of the intermediate state of ZnO related to the anti-Stokes luminescence are discussed.

  4. Hybrid quantum repeater using bright coherent light.

    Science.gov (United States)

    van Loock, P; Ladd, T D; Sanaka, K; Yamaguchi, F; Nemoto, Kae; Munro, W J; Yamamoto, Y

    2006-06-23

    We describe a quantum repeater protocol for long-distance quantum communication. In this scheme, entanglement is created between qubits at intermediate stations of the channel by using a weak dispersive light-matter interaction and distributing the outgoing bright coherent-light pulses among the stations. Noisy entangled pairs of electronic spin are then prepared with high success probability via homodyne detection and postselection. The local gates for entanglement purification and swapping are deterministic and measurement-free, based upon the same coherent-light resources and weak interactions as for the initial entanglement distribution. Finally, the entanglement is stored in a nuclear-spin-based quantum memory. With our system, qubit-communication rates approaching 100 Hz over 1280 km with fidelities near 99% are possible for reasonable local gate errors.

  5. Observation of CARS signal via maximal atomic coherence prepared by F-STIRAP in a three-level atomic system

    National Research Council Canada - National Science Library

    Xiao-Li Song; Lei Wang; Rui-Zhu Lin; Zhi-Hui Kang; Xin Li; Yun Jiang; Jin-Yue Gao

    2007-01-01

    ...) in a L-type configuration, and verify the theoretical predictions. Applying this technique, we are able to prepare the atoms with maximal coherence to enhance coherent anti-Stokes Raman scattering (CARS) signal...

  6. Coherent and thermal light: Tunable hybrid states with second-order coherence without first-order coherence

    Energy Technology Data Exchange (ETDEWEB)

    Blazek, Martin; Elsaesser, Wolfgang [Institute of Applied Physics, Technische Universitaet Darmstadt, Schlossgartenstrasse 7, D-64289 Darmstadt (Germany)

    2011-12-15

    We demonstrate the realization of a new hybrid state of light that is simultaneously spectrally broadband, i.e., in-coherent in first order, and exhibits a laserlike normalized intensity correlation coefficient of 1.33, reflecting high coherence in second order. This is achieved by temperature-tuned light emission from an optoelectronic quantum dot superluminescent diode where the condensation of injected charge carriers into the globally lowest energy state of the strongly inhomogeneously broadened semiconductor quantum dot ensemble gives rise to a particular balance between spontaneous and stimulated emission.

  7. Application of Coherent Anti-Stokes Raman Scattering to Combustion Media.

    Science.gov (United States)

    1981-02-01

    partition function and gI is the nuclear -spin degeneracy. When Maxwell’s equations which describe the propagation of electromagnetic waves are solved...Scanning Spectrometer) shown in Fig. 5. The DARSS unit consists of a linear (one- dimensional) diode array ( reticon ) detector element in conjunction with...electronics scheme it offers. 77 The major problem encountered with the DARSS unit was the single dimensionality of the reticon detector. Previously the

  8. Photon-phonon anti-stokes upconversion of a photonically, electronically, and thermally isolated opal

    Science.gov (United States)

    Stem, Michelle R.

    2016-05-01

    The purpose of the present research was to investigate an intense violet shift displayed by a non-toxic, natural silicate material with a highly ordered nanostructure. The material displayed an unexpected, nonlinear 2:3 photon-phonon anti-Stokes upconversion while photonically, electronically, and thermally isolated. Conducted aphotonically and at ambient temperatures, the specimen upconverted a low-power, 650 nm constant wave red laser to an internally highly dispersed 433 nm violet wavelength. The strong dispersion was largely due to nearly total internal reflection of the laser. The upconversion had an efficiency of about 78 %, based on specimen volume, with no detectable thermal variance. The 2:3 anti-Stokes upconversion displayed by this material is likely the result of a previously unknown photon-phonon evanescence response that amplified the energy of a portion of the incident laser photons. Thus, a portion of the incident laser photons were upconverted, and the material converted another portion into an amplified energy that caused the upconversion. Internal micro-lasing appeared to be a means of photon-phonon evanescent energy redistribution, enabling dispersed photonic upconversion. Additional analyses also found an unexpectedly rhythmic photonic structure in spectrophotometric scans, polariscopic color changing, and previously undocumented ultraviolet responses.

  9. Limiting the intensity of femtosecond pulses with anti-stokes excitation of organic dye solutions

    Science.gov (United States)

    Svetlichnyi, V. A.; Meshalkin, Yu. P.; Kirpichnikov, A. V.; Pestryakov, E. V.

    2010-08-01

    Results of experimental investigations into the nonlinear absorption of the symmetric polymethine 1-butyl -3,3-dimethyl-2-[5-(1-butyl-3,3-dimethyl-3H-benz[e]indoline-2-uledene)-1,3-pentadienyl]-3H-benz[e]indolium perchlorate dye solution excited by radiation of a femtosecond titanium-sapphire laser (20 fs, 800 nm, 75 MHz, and 300 mW) by the open aperture z-scan method are presented. Record limitation of the femtosecond laser radiation intensity (by 300 times at a 93% linear transmission of the medium) was achieved. The nonlinear absorption mechanisms in organic dyes with anti-Stokes excitation by wideband high-power pulsed radiation to the absorption band edge and the prospects for organic dye application for limitation of the femtosecond laser radiation intensity are discussed.

  10. Laser induced broad band anti-Stokes white emission from LiYbF4 nanocrystals

    Institute of Scientific and Technical Information of China (English)

    L. Marciniak; R. Tomala; M. Stefanski; D. Hreniak; W. Strek

    2016-01-01

    Spectroscopic properties of tetragonal LiYbF4 nanocrystals under high dense NIR excitation at vacuum condition were in-vestigated. White, broad band emission covering whole visible part of the spectrum from LiYbF4 nanocrystals was observed. Its in-tensity strongly depended on the excitation power, excitation wavelength and ambient pressure. Temperature of the nanocrystals un-der 975 nm excitation was determined as a function of excitation power. Strong photo-induced current was observed from LiYbF4 pallet. The emission kinetic was analyzed. The mechanism of the anti-Stokes white emission was discussed in terms of the la-ser-induced charge transfer emission from Yb2+ states.

  11. High-efficiency broadband anti-Stokes emission from Yb3+-doped bulk crystals.

    Science.gov (United States)

    Zhu, Siqi; Wang, Chunhao; Li, Zhen; Jiang, Wei; Wang, Yichuan; Yin, Hao; Wu, Lidan; Chen, Zhenqiang; Zhang, Ge

    2016-05-15

    We investigate the broadband anti-Stokes emission (BASE) from Yb3+-doped crystals with a laser diode (LD) pumping at 940 nm. Our experiment reveals that Yb3+-doped crystals with random cracks are able to generate bright BASE at room temperature and atmospheric pressure. By examining the various characteristics of the crystals and the emitted light, we supply a theory for interpreting the underlying physics for this variety of BASE. In particular, we take into consideration the effects of energy migration, avalanche process, and charge-transfer luminescence. This represents the first time, to the best of our knowledge, that BASE was obtained from Yb3+-doped bulk crystals with a high optical-optical efficiency.

  12. Performance analysis of a hybrid fingerprint extracted from optical coherence tomography fingertip scans

    CSIR Research Space (South Africa)

    Darlow, Luke N

    2016-06-01

    Full Text Available International Conference on Biometrics (ICB), 13-16 June 2016, Halmstad, Sweden Performance analysis of a hybrid fingerprint extracted from optical coherence tomography fingertip scans Darlow LN Connan J Singh A ABSTRACT: The Hybrid fingerprint is a...

  13. Utilization of IR laser pumped anti-Stokes emission of Er-Yb doped systems for identification of securities

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmin, A.N.; Ryabtsev, G.I.; Ketko, G.A. [Institute of Physics, Belarussian Academy of Sciences, Minsk (Belarus); Gorelenko, A.Yu.; Demidovich, A.A. [Science Center `Gosznak` of Belarus, Minsk (Belarus); Strek, W.; Maruszewicz, K.; Deren, P. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw (Poland)

    1996-12-31

    In this paper we present a utilization of anti-Stokes luminescence of Er-Yb systems for identification of securities. A simple method of detection of an up-conversion phenomenon in such system by means of IR laser operating in the region 960-1010 nm is proposed. (author) 3 refs, 3 figs

  14. Revealing silent vibration modes of nanomaterials by detecting anti-Stokes hyper-Raman scattering with femtosecond laser pulses

    Science.gov (United States)

    Zeng, Jianhua; Chen, Lei; Dai, Qiaofeng; Lan, Sheng; Tie, Shaolong

    2016-01-01

    We proposed a scheme in which normal Raman scattering is coupled with hyper-Raman scattering for generating a strong anti-Stokes hyper-Raman scattering in nanomaterials by using femtosecond laser pulses. The proposal was experimentally demonstrated by using a single-layer MoS2 on a SiO2/Si substrate, a 17 nm-thick MoS2 on an Au/SiO2 substrate and a 9 nm-thick MoS2 on a SiO2-SnO2/Ag/SiO2 substrate which were confirmed to be highly efficient for second harmonic generation. A strong anti-Stokes hyper-Raman scattering was also observed in other nanomaterials possessing large second-order susceptibilities, such as silicon quantum dots self-assembled into ``coffee'' rings and tubular Cu-doped ZnO nanorods. In all the cases, many Raman inactive vibration modes were clearly revealed in the anti-Stokes hyper-Raman scattering. Apart from the strong anti-Stokes hyper-Raman scattering, Stokes hyper-Raman scattering with small Raman shifts was detected during the ablation process of thick MoS2 layers. It was also observed by slightly defocusing the excitation light. The detection of anti-Stokes hyper-Raman scattering may serve as a new technique for studying the Raman inactive vibration modes in nanomaterials.We proposed a scheme in which normal Raman scattering is coupled with hyper-Raman scattering for generating a strong anti-Stokes hyper-Raman scattering in nanomaterials by using femtosecond laser pulses. The proposal was experimentally demonstrated by using a single-layer MoS2 on a SiO2/Si substrate, a 17 nm-thick MoS2 on an Au/SiO2 substrate and a 9 nm-thick MoS2 on a SiO2-SnO2/Ag/SiO2 substrate which were confirmed to be highly efficient for second harmonic generation. A strong anti-Stokes hyper-Raman scattering was also observed in other nanomaterials possessing large second-order susceptibilities, such as silicon quantum dots self-assembled into ``coffee'' rings and tubular Cu-doped ZnO nanorods. In all the cases, many Raman inactive vibration modes were clearly

  15. Anti-Stokes Frequency Shift and Evolution in Polarization-Maintaining Photonic Crystal Fiber with Two-Zero Dispersion Wavelengths

    Institute of Scientific and Technical Information of China (English)

    WANG He-Lin; LENG Yu-Xin; XU Zhi-Zhan; QI Yi-Hong; HU Ming-Lie; WANG Ching-Yue

    2009-01-01

    Using the tunable pump pulses with about 100 fs pulse duration and 1064 nm central wavelength; the polarization-,wavelength- and power-dependent anti-Stokes lines are generated and modulated simultaneously in a polarizationmaintaining photonic crystal fiber (PM-PCF) with two zero-dispersion wavelengths.By accurately controlling the polarization directions,the wavelength and the power of the pump pulse in the fiber anomalous region close to the second zero-dispersion wavelength of the PM-PCF,the output anti-Stokes pulse spectra can be tuned between 563nm and 603 nm,which is in good agreement with the theoretical simulation.The color conversion of the mode image from yellow to orange is also observed with the different polarization pump pulses.These results can be attributed to the combined interaction between the fiber birefringence (including linear- and nonlinearbirefringence) and dispersion,and are attributed to phase-matching parametric four-wave mixing.

  16. Green and red Anti-Stokes emission of U3+: LaCl3produced by infrared laser

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Anti-Stokes green and red emission from U3+: LaCl3 can be produced by infrared laser excitation at 975.3 nm, 977.7 nm and 979.4 nm at 8K. The upconversion luminescence intensity dependence upon the excitation laser power was measured and analyzed. The results show that depending on the excitation wavelength, the mechanisms responsible for the upconversion process are two-photon absorption and excited-state absorption.

  17. A new filtering technique for removing anti-Stokes emission background in gated CW-STED microscopy.

    Science.gov (United States)

    Coto Hernàndez, Ivàn; Peres, Chiara; Cella Zanacchi, Francesca; d'Amora, Marta; Christodoulou, Sotirios; Bianchini, Paolo; Diaspro, Alberto; Vicidomini, Giuseppe

    2014-06-01

    Stimulated emission depletion (STED) microscopy is a prominent approach of super-resolution optical microscopy, which allows cellular imaging with so far unprecedented unlimited spatial resolution. The introduction of time-gated detection in STED microscopy significantly reduces the (instantaneous) intensity required to obtain sub-diffraction spatial resolution. If the time-gating is combined with a STED beam operating in continuous wave (CW), a cheap and low labour demand implementation is obtained, the so called gated CW-STED microscope. However, time-gating also reduces the fluorescence signal which forms the image. Thereby, background sources such as fluorescence emission excited by the STED laser (anti-Stokes fluorescence) can reduce the effective resolution of the system. We propose a straightforward method for subtraction of anti-Stokes background. The method hinges on the uncorrelated nature of the anti-Stokes emission background with respect to the wanted fluorescence signal. The specific importance of the method towards the combination of two-photon-excitation with gated CW-STED microscopy is demonstrated. Copyright © 2014 The Authors. J. Biophotonics published by Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim • This is an open access article under the terms of the Creative Commons Attribution-License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

  18. Evolution of intensity noise and hybrid correlation

    Science.gov (United States)

    Ahmed, Irfan; Lau, Condon; Wang, Ruimin; Zhang, Da; Li, Xinghua; Li, Kangkang; Li, Changbiao; Zhang, Yanpeng

    2017-06-01

    We report the evolution of spontaneous parametric four-wave mixing (SP-FWM) as a small peak in the dip of Autler-Townes splitting in the medium of coherent non linear crystal of Pr3+:Y2SiO5. We demonstrate the results of a composite signal with evolution from pure fluorescence to a hybrid state of light to pure SP-FWM. By investigating the composite signal in frequency/time domains and studying hybrid correlations (positive/negative or anti-correlation) among three channels, i.e. Stokes (anti-Stokes) with composite signal, we demonstrate the evolution of SP-FWM processes from fluorescence. Such correlations can have potential applications in all-optical communication and quantum teleportation.

  19. Protein expression guided chemical profiling of living cells by the simultaneous observation of Raman scattering and anti-Stokes fluorescence emission

    Science.gov (United States)

    Chiu, Liang-da; Ichimura, Taro; Sekiya, Takumasa; Machiyama, Hiroaki; Watanabe, Tomonobu; Fujita, Hideaki; Ozawa, Takeaki; Fujita, Katsumasa

    2017-01-01

    Our current understanding of molecular biology provides a clear picture of how the genome, transcriptome and proteome regulate each other, but how the chemical environment of the cell plays a role in cellular regulation remains much to be studied. Here we show an imaging method using hybrid fluorescence-Raman microscopy that measures the chemical micro-environment associated with protein expression patterns in a living cell. Simultaneous detection of fluorescence and Raman signals, realised by spectrally separating the two modes through the single photon anti-Stokes fluorescence emission of fluorescent proteins, enables the accurate correlation of the chemical fingerprint of a specimen to its physiological state. Subsequent experiments revealed the slight chemical differences that enabled the chemical profiling of mouse embryonic stem cells with and without Oct4 expression. Furthermore, using the fluorescent probe as localisation guide, we successfully analysed the detailed chemical content of cell nucleus and Golgi body. The technique can be further applied to a wide range of biomedical studies for the better understanding of chemical events during biological processes. PMID:28272392

  20. Generation of femtosecond anti-stokes pulses through phase-matched parametric four-wave mixing in a photonic crystal fiber.

    Science.gov (United States)

    Konorov, S O; Serebryannikov, E E; Zheltikov, A M; Zhou, Ping; Tarasevitch, A P; von der Linde, D

    2004-07-01

    Phase-matched parametric four-wave mixing in higher-order guided modes of a photonic crystal fiber is shown to result in an efficient decay of 40-fs 800-nm Ti:sapphire laser pump pulses into an anti-Stokes signal with a central wavelength around 590-600 nm and a Stokes signal centered at 1.25 microm. The photonic crystal fiber is designed in such a way as to minimize the group-velocity dispersion at the pump wavelength, phase match the parametric four-wave-mixing process, and reduce the group delay between the pump and the anti-Stokes pulses. The duration of the anti-Stokes pulse under these conditions, as shown by cross-correlation frequency-resolved optical gating measurements, is less than 200 fs.

  1. Coherent resonance of quantum plasmons in the graphene-gold cluster hybrid system.

    Science.gov (United States)

    Zhang, Kaibiao; Zhang, Hong; Li, Chikang

    2015-05-14

    Noble metal nanoparticles can modify the optical properties of graphene. Here we present a detailed theoretical analysis of the coherent resonance of quantum plasmons in the graphene-gold cluster hybrid system by using time dependent density functional theory (TDDFT). This plasmon coherent effect is mainly attributed to the electromagnetic field coupling between the graphene and the gold cluster. As a result, the optical response of the hybrid system exhibits a remarkably strong, selectable tuning and polarization dependent plasmon resonance enhanced in wide frequency regions. This investigation provides an improved understanding of the plasmon enhancement effect in a graphene-based photoelectric device.

  2. Measurement of detonation temperature of hydrogen-oxygen mixture by CARS (Coherent Anti-Stokes Raman Spectroscopy)

    Science.gov (United States)

    Tezaki, Atsumu; Matsui, Hiroyuki; Kawamura, Yoshiro

    1988-01-01

    It was confirmed that CARS is very useful as a temperature measurement method of detonation. By revising the detecting system so that a lot of information can be handled simultaneously like an optical multi-channel analyzer, it is possible to obtain information concerning the detailed three dimensional structure of detonation which has never been obtained.

  3. In situ dissolution analysis of pharmaceutical dosage forms using coherent anti-Stokes Raman scattering (CARS) microscopy

    Science.gov (United States)

    Fussell, A. L.; Garbacik, E. T.; Löbmann, K.; Offerhaus, H. L.; Kleinebudde, P.; Strachan, C. J.

    2014-02-01

    A custom-built intrinsic flow-through dissolution setup was developed and incorporated into a home-built CARS microscope consisting of a synchronously pumped optical parametric oscillator (OPO) and an inverted microscope with a 20X/0.5NA objective. CARS dissolution images (512×512 pixels) were collected every 1.12s for the duration of the dissolution experiment. Hyperspectral CARS images were obtained pre- and postdissolution by rapidly imaging while sweeping the wavelength of the OPO in discrete steps so that each frame in the data stack corresponds to a vibrational frequency. An image-processing routine projects this hyperspectral data into a single image wherein each compound appears with a unique color. Dissolution was conducted using theophylline and cimetidine-naproxen co-amorphous mixture. After 15 minutes of theophylline dissolution, hyperspectral imaging showed a conversion of theophylline anhydrate to the monohydrate, confirmed by a peak shift in the CARS spectra. CARS dissolution images showed that monohydrate crystal growth began immediately and reached a maximum with complete surface coverage at about 300s. This result correlated with the UV dissolution data where surface crystal growth on theophylline compacts resulted in a rapidly reducing dissolution rate during the first 300s. Co-amorphous cimetidinenaproxen didn't appear to crystallize during dissolution. We observed solid-state conversions on the compact's surface in situ during dissolution. Hyperspectral CARS imaging allowed visual discrimination between the solid-state forms on the compact's surface. In the case of theophylline we were able to correlate the solid-state change with a change in dissolution rate.

  4. Chemical Imaging of Oral Solid Dosage Forms and Changes upon Dissolution Using Coherent Anti-Stokes Raman Scattering Microscopy

    NARCIS (Netherlands)

    Windbergs, Maike; Jurna, Martin; Offerhaus, Herman L.; Herek, Jennifer L.; Kleinebudde, Peter; Strachan, Clare J.

    2009-01-01

    Dissolution testing is a crucial part of pharmaceutical dosage form investigations and is generally performed by analyzing the concentration of the released drug in a defined volume of flowing dissolution medium. As solid-state properties of the components affect dissolution behavior to a large and

  5. Investigation of Optical Fibers for Coherent Anti-Stokes Raman Scattering (CARS) Spectroscopy in Reacting Flows (Postprint)

    Science.gov (United States)

    2012-03-01

    notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not...OF ABSTRACT: SAR 18. NUMBER OF PAGES 22 19a. NAME OF RESPONSIBLE PERSON (Monitor) a. REPORT Unclassified b. ABSTRACT Unclassified c...Seeger of the University of Erlangen- Nuremberg , Prof. Margaret M. Murnane of the University of Colorado/JILA, and Dr. Hans Stauffer and Ms. Amy Lynch

  6. Distinguishing non-resonant four-wave-mixing noise in coherent stokes and anti-stokes Raman scattering

    Science.gov (United States)

    Marks, Daniel L. (Inventor); Boppart, Stephen A. (Inventor)

    2009-01-01

    A method of examining a sample comprises exposing the sample to a pump pulse of electromagnetic radiation for a first period of time, exposing the sample to a stimulant pulse of electromagnetic radiation for a second period of time which overlaps in time with at least a portion of the first exposing, to produce a signal pulse of electromagnetic radiation for a third period of time, and interfering the signal pulse with a reference pulse of electromagnetic radiation, to determine which portions of the signal pulse were produced during the exposing of the sample to the stimulant pulse. The first and third periods of time are each greater than the second period of time.

  7. Conceptual Design Study for Coherent Anti-Stokes Raman Spectroscopy (CARS) Diagnostics in the AMMRC Ballistic Compressor Facility.

    Science.gov (United States)

    1980-03-01

    1980 Army Materials and Mechanics Research Cne Watertown, Massachusetts 02172 4 MONITORING AGENCY NAME IADDRESS(diffetret from. Controlling Offe) iS... dumpers can be modulated from a few megahertz to single shot. With mode locking the frequency is fixed by the cavity round trip time which is on the order

  8. Study of statistical properties of hybrid statistic in coherent multidetector compact binary coalescences search

    Science.gov (United States)

    Haris, K.; Pai, Archana

    2016-05-01

    In this article, we revisit the coherent gravitational wave search problem of compact binary coalescences with multidetector network consisting of advanced interferometers like LIGO-Virgo. Based on the loss of the optimal multidetector signal-to-noise ratio (SNR), we construct a hybrid statistic as a best of maximum-likelihood-ratio (MLR) statistic tuned for face-on and face-off binaries. The statistical properties of the hybrid statistic is studied. The performance of this hybrid statistic is compared with that of the coherent MLR statistic for generic inclination angles. Owing to the single synthetic data stream, the hybrid statistic gives few false alarms compared to the multidetector MLR statistic and small fractional loss in the optimum SNR for a large range of binary inclinations. We demonstrate that, for a LIGO-Virgo network and binary inclination ɛ 11 0 ° , the hybrid statistic captures more than 98% of the network optimum matched filter SNR with a low false alarm rate. The Monte Carlo exercise with two distributions of incoming inclination angles—namely, U [cos ɛ ] and a more realistic distribution proposed by B. F. Schutz [Classical Quantum Gravity 28, 125023 (2011)]—are performed with the hybrid statistic and give approximately 5% and 7% higher detection probabilities, respectively, compared to the two stream multidetector MLR statistic for a fixed false alarm probability of 1 0-5.

  9. High-order Stokes and anti-Stokes Raman generation in monoisotopic CVD {sup 12}C-diamond

    Energy Technology Data Exchange (ETDEWEB)

    Kaminskii, Alexander A. [Institute of Crystallography, Russian Academy of Sciences, Moscow (Russian Federation); Lux, Oliver; Rhee, Hanjo; Eichler, Hans J. [Institute of Optics and Atomic Physics, Technische Universitaet Berlin (Germany); Ralchenko, Victor G.; Bolshakov, Andrey P. [General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Shirakawa, Akira; Yoneda, Hitoki [Institute for Laser Science, University of Electro-Communications, Tokyo (Japan)

    2016-06-15

    We determined, for the first time, the room temperature phonon energy related to the F{sub 2g} vibration mode (ω{sub SRS(12C)} ∝ 1333.2 cm{sup -1}) in a mono-crystalline single-isotope CVD {sup 12}C-diamond crystal by means of stimulated Raman scattering (SRS) spectroscopy. Picosecond one-micron excitation using a Nd{sup 3+}:Y{sub 3}Al{sub 5}O{sub 12}-laser generates a nearly two-octave spanning SRS frequency comb (∝12000 cm{sup -1}) consisting of higher-order Stokes and anti-Stokes components. The spacing of the spectral lines was found to differ by Δω{sub SRS} ∝ 0.9 cm{sup -1} from the comb spacing (ω{sub SRS(natC)} ∝ 1332.3 cm{sup -1}) when pumping a conventional CVD diamond crystal with a natural composition of the two stable carbon isotopes {sup 12}C (98.93%) and {sup 13}C (1.07%). (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Anti-Stokes resonant x-ray Raman scattering for atom specific and excited state selective dynamics

    Science.gov (United States)

    Kunnus, Kristjan; Josefsson, Ida; Rajkovic, Ivan; Schreck, Simon; Quevedo, Wilson; Beye, Martin; Grübel, Sebastian; Scholz, Mirko; Nordlund, Dennis; Zhang, Wenkai; Hartsock, Robert W.; Gaffney, Kelly J.; Schlotter, William F.; Turner, Joshua J.; Kennedy, Brian; Hennies, Franz; Techert, Simone; Wernet, Philippe; Odelius, Michael; Föhlisch, Alexander

    2016-10-01

    Ultrafast electronic and structural dynamics of matter govern rate and selectivity of chemical reactions, as well as phase transitions and efficient switching in functional materials. Since x-rays determine electronic and structural properties with elemental, chemical, orbital and magnetic selectivity, short pulse x-ray sources have become central enablers of ultrafast science. Despite of these strengths, ultrafast x-rays have been poor at picking up excited state moieties from the unexcited ones. With time-resolved anti-Stokes resonant x-ray Raman scattering (AS-RXRS) performed at the LCLS, and ab initio theory we establish background free excited state selectivity in addition to the elemental, chemical, orbital and magnetic selectivity of x-rays. This unparalleled selectivity extracts low concentration excited state species along the pathway of photo induced ligand exchange of Fe(CO)5 in ethanol. Conceptually a full theoretical treatment of all accessible insights to excited state dynamics with AS-RXRS with transform-limited x-ray pulses is given—which will be covered experimentally by upcoming transform-limited x-ray sources.

  11. Study of statistical properties of hybrid statistic in coherent multi-detector CBC Search

    CERN Document Server

    Haris, K

    2015-01-01

    In this article, we revisit the problem of coherent multi-detector search of gravitational wave from compact binary coalescence with Neutron stars and Black Holes using advanced interferometers like LIGO-Virgo. Based on the loss of optimal multi-detector signal-to-noise ratio (SNR), we construct a hybrid statistic as a best of maximum-likelihood-ratio(MLR) statistic tuned for face-on and face-off binaries. The statistical properties of the hybrid statistic is studied. The performance of this hybrid statistic is compared with that of the coherent MLR statistic for generic inclination angles. Owing to the single synthetic data stream, the hybrid statistic gives low false alarms compared to the multi-detector MLR statistic and small fractional loss in the optimum SNR for a large range of binary inclinations. We have demonstrated that for a LIGO-Virgo network and binary inclination, \\epsilon 110 deg., the hybrid statistic captures more than 98% of network optimum matched filter SNR with low false alarm rate. The...

  12. Hybrid-integrated coherent receiver using silica-based planar lightwave circuit technology

    Science.gov (United States)

    Kim, Jong-Hoi; Choe, Joong-Seon; Choi, Kwang-Seong; Youn, Chun-Ju; Kim, Duk-Jun; Jang, Sun-Hyok; Kwon, Yong-Hwan; Nam, Eun-Soo

    2011-12-01

    A hybrid-integrated coherent receiver module has been achieved using flip-chip bonding technology, consisting of a silica-based 90°-hybrid planar lightwave circuit (PLC) platform, a spot-size converter integrated waveguide photodiode (SSC-WG-PD), and a dual-channel transimpedance amplifier (TIA). The receiver module shows error-free operation up to 40Gb/s and OSNR sensitivity of 11.5 dB for BER = 10-3 at 25 Gb/s.

  13. Efficient scheme for hybrid teleportation via entangled coherent states in circuit quantum electrodynamics.

    Science.gov (United States)

    Joo, Jaewoo; Ginossar, Eran

    2016-06-01

    We propose a deterministic scheme for teleporting an unknown qubit state through continuous-variable entangled states in superconducting circuits. The qubit is a superconducting two-level system and the bipartite quantum channel is a microwave photonic entangled coherent state between two cavities. A Bell-type measurement performed on the hybrid state of solid and photonic states transfers a discrete-variable unknown electronic state to a continuous-variable photonic cat state in a cavity mode. In order to facilitate the implementation of such complex protocols we propose a design for reducing the self-Kerr nonlinearity in the cavity. The teleporation scheme enables quantum information processing operations with circuit-QED based on entangled coherent states. These include state verification and single-qubit operations with entangled coherent states. These are shown to be experimentally feasible with the state of the art superconducting circuits.

  14. Efficient scheme for hybrid teleportation via entangled coherent states in circuit quantum electrodynamics

    Science.gov (United States)

    Joo, Jaewoo; Ginossar, Eran

    2016-06-01

    We propose a deterministic scheme for teleporting an unknown qubit state through continuous-variable entangled states in superconducting circuits. The qubit is a superconducting two-level system and the bipartite quantum channel is a microwave photonic entangled coherent state between two cavities. A Bell-type measurement performed on the hybrid state of solid and photonic states transfers a discrete-variable unknown electronic state to a continuous-variable photonic cat state in a cavity mode. In order to facilitate the implementation of such complex protocols we propose a design for reducing the self-Kerr nonlinearity in the cavity. The teleporation scheme enables quantum information processing operations with circuit-QED based on entangled coherent states. These include state verification and single-qubit operations with entangled coherent states. These are shown to be experimentally feasible with the state of the art superconducting circuits.

  15. Anti-Stokes emissions and determination of Stark sub-level diagram of Er{sup 3+} ions in KY{sub 3}F{sub 10}

    Energy Technology Data Exchange (ETDEWEB)

    Boulma, E [Laboratoire d' Energetique et d' Optique, UTAP, Universite de Reims Champagne-Ardenne, BP 1039, Reims Cedex 51 687 (France); Diaf, M [Departement de Physique, Universite Badji Mokhtar Annaba, BP12, 23000 Annaba, Algerie (Germany); Jouart, J P [Laboratoire d' Energetique et d' Optique, UTAP, Universite de Reims Champagne-Ardenne, BP 1039, Reims Cedex 51 687 (France); Bouffard, M [Laboratoire d' Energetique et d' Optique, UTAP, Universite de Reims Champagne-Ardenne, BP 1039, Reims Cedex 51 687 (France); Doualan, J L [Centre Interdisciplinaire de Recherches Ions Lasers (CIRIL), UMR 6637 CNRS-CEA-ISMRA, ENSI de Caen, 6 Boulevard Marechal Juin, 14050 Caen Cedex (France); Moncorge, R [Centre Interdisciplinaire de Recherches Ions Lasers (CIRIL), UMR 6637 CNRS-CEA-ISMRA, ENSI de Caen, 6 Boulevard Marechal Juin, 14050 Caen Cedex (France)

    2006-07-26

    We are interested, in this work, in determining the Stark sub-level of Er{sup 3+} ions doping a KY{sub 3}F{sub 10} single crystal with a molar concentration of 1%. We have used a new method of measurement of energies of the ground level and emitting levels from excitation and anti-Stokes emission spectra recorded at liquid nitrogen temperature. This technique is based on a spectral analysis of the anti-Stokes emissions recorded after selective excitation with a red dye tunable laser. Thus, we could determine the Stark sub-levels of the ground and the principal emitting levels in the infrared, visible and near-UV ranges with a very good precision.

  16. Design of 2*6 optical hybrid in inter-satellite coherent laser communications

    Science.gov (United States)

    Xu, Nan; Liu, Liren; Liu, De'an; Wan, Lingyu; Zhou, Yu

    2008-08-01

    Compared with direct detection, homodyne binary phase shift keying receivers can achieve the best sensitivity theoretically, and became the trend of the research and application in inter-satellite coherent laser communications. In coherent optical communication systems an optical hybrid is an essential component of the receiver. It demodulates the incoming signal by mixing it with the local oscillator. We present a design of a 2*6 optical hybrid. 4 output ports of the hybrid give the narrow mixed beams of the incoming signal and the local oscillator shifted by 90°for communication, and the others give the wide mixed beams with a shifted degree of 180°for position errors detection. CCD captures the interference pattern from the wide beams, and then the pattern is processed and analyzed by the computer. Target position information is obtained from characteristic parameter of the interference pattern. The position errors as the control signals of PAT (pointing, acquisition and tracking) subsystem drive the receiver telescope to keep tracking to the target. The application extends to coherent laser rang finder.

  17. The application of Raman and anti-stokes Raman spectroscopy for in situ monitoring of structural changes in laser irradiated titanium dioxide materials

    Energy Technology Data Exchange (ETDEWEB)

    Rigby, Stephanie J. [Centre for Research in Energy and Environment, School of Engineering, Robert Gordon University, Aberdeen AB10 1FR (United Kingdom); Al-Obaidi, Ala H.R. [Smart Light Devices, Unit 13, Tyseal Base, Craigshaw Crescent Aberdeen, West Tullos Industrial Estate, Aberdeen AB12 3AW (United Kingdom); Lee, Soo-Keun [School of Environmental Science and Engineering, POSTECH, San 31 Hyoja Dong Nam-Gu, Pohang, Kyungpook 790-784 (Korea, Republic of); McStay, Daniel [Discovery Technologies Ltd., Redshank House, Alness Point Business Park, Alness IV17 0IJ (United Kingdom); Robertson, Peter K.J. [Centre for Research in Energy and Environment, School of Engineering, The Robert Gordon University, Aberdeen AB10 1FR (United Kingdom)]. E-mail: peter.robertson@rgu.ac.uk

    2006-09-15

    The use of Raman and anti-stokes Raman spectroscopy to investigate the effect of exposure to high power laser radiation on the crystalline phases of TiO{sub 2} has been investigated. Measurement of the changes, over several time integrals, in the Raman and anti-stokes Raman of TiO{sub 2} spectra with exposure to laser radiation is reported. Raman and anti-stokes Raman provide detail on both the structure and the kinetic process of changes in crystalline phases in the titania material. The effect of laser exposure resulted in the generation of increasing amounts of the rutile crystalline phase from the anatase crystalline phase during exposure. The Raman spectra displayed bands at 144 cm{sup -1} (A1g), 197 cm{sup -1} (Eg), 398 cm{sup -1} (B1g), 515 cm{sup -1} (A1g), and 640 cm{sup -1} (Eg) assigned to anatase which were replaced by bands at 143 cm{sup -1} (B1g), 235 cm{sup -1} (2 phonon process), 448 cm{sup -1} (Eg) and 612 cm{sup -1} (A1g) which were assigned to rutile. This indicated that laser irradiation of TiO{sub 2} changes the crystalline phase from anatase to rutile. Raman and anti-stokes Raman are highly sensitive to the crystalline forms of TiO{sub 2} and allow characterisation of the effect of laser irradiation upon TiO{sub 2}. This technique would also be applicable as an in situ method for monitoring changes during the laser irradiation process.

  18. Measurement of the He 1s2s (1)S(0) isotopic shift using a tunable VUV anti-Stokes light source.

    Science.gov (United States)

    Falcone, R W; Willison, J R; Young, J F; Harris, S E

    1978-11-01

    We describe a high-resolution, vacuum-ultraviolet spectroscopic technique based on a tunable, narrow-band, VUV, spontaneous anti-Stokes light source. The technique was used to measure the absolute energies of the 1s2s (1)S(0) states of (3)He and (4)He; the 1s2s (1)S(0) level of (3)He is 7.8 +/- 0.5 cm(-1) below that of (4)He.

  19. Anti-Stokes Resonance Raman of Ir Illuminated Dendrimer Iron (III)-Porphyrins%红外辐照下树枝状铁(iii)卟啉的反斯托克斯共振拉曼

    Institute of Scientific and Technical Information of China (English)

    MO Yu-jun; D.L.Jiang; M.Uymura; T.Aida; T.Kitagawa

    2005-01-01

    The benzene dendrimers of Fe(Ⅲ) tetraphenyl porphyrin chloride[LnFe(Ⅲ)TPPCl] with n = 3, 4, and 5 (n: number of layers) have been synthesized and the IR illumination effects at benzene bands were examined with anti- Stokes resonance Raman speetroseopy for their dioxane solutions.Boltzman temperatures were determined from the Stokes to anti - Stokes intensity ratio for the speetra excited at 413.1 nm in the presence and absence of IR illumination.

  20. Coherent resonance of quantum plasmons in Stone-Wales defected graphene-silver nanowire hybrid system

    Science.gov (United States)

    Liu, Tong; Zhang, Hong; Cheng, Xin-Lu; Xu, Yang

    2017-10-01

    Defected graphene has a more important practical significance than graphene. Silver nanoparticles can modify the optical properties of defected graphene. We present herein a detailed theoretical analysis about the coherent resonance of quantum plasmons in the Stone-Wales (SW) defected graphene-silver nanowire hybrid system by using time-dependent density functional theory. The plasmon coherent effect is mainly attributed to the electromagnetic field coupling between the Stone-Wales defected graphene and silver nanowires. As a result, the optical response of the hybrid system exhibits a remarkable enhancement. Plasmon resonance, which depends on polarization and selectable tuning, is enhanced in wide frequency regions. Moreover, it reveals that the resonance frequency of an optical absorption spectrum depends on the space configuration of the SW defected graphene in the hybrid system. This investigation provides a better understanding of the plasmon enhancement effect used in a graphene-based photoelectric device. The study also offers an effective means of detecting the defects existing in graphene.

  1. Directly modulated and fully tunable hybrid silicon lasers for future generation of coherent colorless ONU.

    Science.gov (United States)

    de Valicourt, G; Le Liepvre, A; Vacondio, F; Simonneau, C; Lamponi, M; Jany, C; Accard, A; Lelarge, F; Make, D; Poingt, F; Duan, G H; Fedeli, J-M; Messaoudene, S; Bordel, D; Lorcy, L; Antona, J-C; Bigo, S

    2012-12-10

    We propose and demonstrate asymmetric 10 Gbit/s upstream--100 Gbit/s downstream per wavelength colorless WDM/TDM PON using a novel hybrid-silicon chip integrating two tunable lasers. The first laser is directly modulated in burst mode for upstream transmission over up to 25 km of standard single mode fiber and error free transmission over 4 channels across the C-band is demonstrated. The second tunable laser is successfully used as local oscillator in a coherent receiver across the C-band simultaneously operating with the presence of 80 downstream co-channels.

  2. Experimental demonstration of mode-selective phonon excitation of 6H-SiC by a mid-infrared laser with anti-Stokes Raman scattering spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Kyohei; Hachiya, Kan; Okumura, Kensuke; Mishima, Kenta; Inukai, Motoharu; Torgasin, Konstantin; Omer, Mohamed [Graduate School of Energy Science, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Sonobe, Taro [Kyoto University Research Administration Office, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Zen, Heishun; Negm, Hani; Kii, Toshiteru; Masuda, Kai; Ohgaki, Hideaki [Institute of Advanced Energy, Kyoto University, Gokasyo, Uji, Kyoto 611-0011 (Japan)

    2013-10-28

    Mode-selective phonon excitation by a mid-infrared laser (MIR-FEL) is demonstrated via anti-Stokes Raman scattering measurements of 6H-silicon carbide (SiC). Irradiation of SiC with MIR-FEL and a Nd-YAG laser at 14 K produced a peak where the Raman shift corresponds to a photon energy of 119 meV (10.4 μm). This phenomenon is induced by mode-selective phonon excitation through the irradiation of MIR-FEL, whose photon energy corresponds to the photon-absorption of a particular phonon mode.

  3. Coherence Imaging Measurements of Impurity Flow in the Compact Toroidal Hybrid Experiment

    Science.gov (United States)

    Ennis, D. A.; Hartwell, G. J.; Johnson, C. A.; Maurer, D. A.; Allen, S. L.; Meyer, W. H.; Samuell, C. M.

    2016-10-01

    Measurements of impurity ion emissivity and velocity in the Compact Toroidal Hybrid (CTH) experiment are achieved with a new optical coherence imaging diagnostic. The Coherence Imaging Spectroscopy (CIS) technique measures the spectral coherence of an emission line with an imaging interferometer of fixed delay. CIS has a number of advantages when compared to dispersive Doppler spectroscopy, including higher throughput and the capability to provide 2D spectral images, making it ideal for investigating the non-axisymmetric geometry of CTH plasmas. Furthermore, detailed measurements of the ion flow structure provided by CIS combined with predictive computational models could also provide spatially resolved images of complex flow structures, such as those associated with an island divertor. First CIS measurements of CTH plasmas reveal strong signals for C III (465 nm), He II (468 nm) and C II (513 nm) emission. Preliminary analysis of C III interferograms indicate a net toroidal flow on the order of 10 km/s during the time of peak current. Bench tests using Zn and Cd light sources reveal that the temperature of the instrument must be actively controlled to within 0.01°C to limit phase drift of the interferometer resulting in artificially measured flow. Results from this diagnostic will aid in characterizing the ion flow in planned island divertor and MHD mode-locking experiments. Work supported by USDoE Grant DE-FG02-00ER54610.

  4. First Results from a Coherence Imaging Diagnostic for the Compact Toroidal Hybrid

    Science.gov (United States)

    Ennis, D. A.; Hartwell, G. J.; Johnson, C. A.; Maurer, D. A.; Allen, S. L.

    2015-11-01

    An optical coherence imaging diagnostic is being commissioned for time-resolved measurements (~ 10 ms) of ion emissivity, velocity, and temperature in the Compact Toroidal Hybrid (CTH) experiment. The Coherence Imaging (CI) technique measures the spectral coherence of an emission line with an imaging interferometer of fixed delay. CI has a number of advantages when compared to dispersive Doppler spectroscopy, including higher throughput and the capability to provide 2D spectral images, making it advantageous for investigating the non-axisymmetric geometry of CTH plasmas. A spectral survey of the visible and ultraviolet emission for a range of CTH discharges has identified helium and carbon impurity lines that will be utilized for CI measurements in CTH. First CI measurements of He II (468.6 nm) emission from CTH plasmas will be presented along with interferograms from a calibration light source and details of the instrument design. Results from this diagnostic will aid in characterizing the equilibrium ion parameters in both the edge and core of CTH plasmas for planned island divertor and MHD mode-locking experiments. Work supported by USDoE grant DE-FG02-00ER54610.

  5. Extraction of linear anisotropic parameters using optical coherence tomography and hybrid Mueller matrix formalism.

    Science.gov (United States)

    Liao, Chia-Chi; Lo, Yu-Lung

    2015-04-20

    A method is proposed for extracting the linear birefringence (LB) and linear dichroism (LD) properties of an anisotropic optical sample using reflection-mode optical coherence tomography (OCT) and a hybrid Mueller matrix formalism. To ensure the accuracy of the extracted parameter values, a method is proposed for calibrating and compensating the polarization distortion effect induced by the beam splitters in the OCT system using a composite quarter-waveplate / half-waveplate / quarter-waveplate structure. The validity of the proposed method is confirmed by extracting the LB and LD properties of a quarter-wave plate and a defective polarizer. To the best of the authors' knowledge, the method proposed in this study represents the first reported attempt to utilize an inverse Mueller matrix formalism and a reflection-mode OCT structure to extract the LB and LD parameters of optically anisotropic samples.

  6. Surpassing the no-cloning limit with a heralded hybrid linear amplifier for coherent states

    Science.gov (United States)

    Haw, Jing Yan; Zhao, Jie; Dias, Josephine; Assad, Syed M.; Bradshaw, Mark; Blandino, Rémi; Symul, Thomas; Ralph, Timothy C.; Lam, Ping Koy

    2016-10-01

    The no-cloning theorem states that an unknown quantum state cannot be cloned exactly and deterministically due to the linearity of quantum mechanics. Associated with this theorem is the quantitative no-cloning limit that sets an upper bound to the quality of the generated clones. However, this limit can be circumvented by abandoning determinism and using probabilistic methods. Here, we report an experimental demonstration of probabilistic cloning of arbitrary coherent states that clearly surpasses the no-cloning limit. Our scheme is based on a hybrid linear amplifier that combines an ideal deterministic linear amplifier with a heralded measurement-based noiseless amplifier. We demonstrate the production of up to five clones with the fidelity of each clone clearly exceeding the corresponding no-cloning limit. Moreover, since successful cloning events are heralded, our scheme has the potential to be adopted in quantum repeater, teleportation and computing applications.

  7. High-Speed Coherent Raman Fingerprint Imaging of Biological Tissues

    CERN Document Server

    Camp, Charles H; Heddleston, John M; Hartshorn, Christopher M; Walker, Angela R Hight; Rich, Jeremy N; Lathia, Justin D; Cicerone, Marcus T

    2014-01-01

    We have developed a coherent Raman imaging platform using broadband coherent anti-Stokes Raman scattering (BCARS) that provides an unprecedented combination of speed, sensitivity, and spectral breadth. The system utilizes a unique configuration of laser sources that probes the Raman spectrum over 3,000 cm$^{-1}$ and generates an especially strong response in the typically weak Raman "fingerprint" region through heterodyne amplification of the anti-Stokes photons with a large nonresonant background (NRB) while maintaining high spectral resolution of $<$ 13 cm$^{-1}$. For histology and pathology, this system shows promise in highlighting major tissue components in a non-destructive, label-free manner. We demonstrate high-speed chemical imaging in two- and three-dimensional views of healthy murine liver and pancreas tissues and interfaces between xenograft brain tumors and the surrounding healthy brain matter.

  8. Parametric Raman anti-Stokes laser at 503 nm with phase-matched collinear beam interaction of orthogonally polarized Raman components in calcite under 532 nm 20 ps laser pumping

    Science.gov (United States)

    Smetanin, Sergei; Jelínek, Michal; Kubeček, Václav

    2017-05-01

    Lasers based on stimulated-Raman-scattering process can be used for the frequency-conversion to the wavelengths that are not readily available from solid-state lasers. Parametric Raman lasers allow generation of not only Stokes, but also anti-Stokes components. However, practically all the known crystalline parametric Raman anti-Stokes lasers have very low conversion efficiencies of about 1 % at theoretically predicted values of up to 40 % because of relatively narrow angular tolerance of phase matching in comparison with angular divergence of the interacting beams. In our investigation, to widen the angular tolerance of four-wave mixing and to obtain high conversion efficiency into the antiStokes wave we propose and study a new scheme of the parametric Raman anti-Stokes laser at 503 nm with phasematched collinear beam interaction of orthogonally polarized Raman components in calcite under 532 nm 20 ps laser pumping. We use only one 532-nm laser source to pump the Raman-active calcite crystal oriented at the phase matched angle for orthogonally polarized Raman components four-wave mixing. Additionally, we split the 532-nm laser radiation into the orthogonally polarized components entering to the Raman-active calcite crystal at the certain incidence angles to fulfill the tangential phase matching compensating walk-off of extraordinary waves for collinear beam interaction in the crystal with the widest angular tolerance of four-wave mixing. For the first time the highest 503-nm anti-Stokes conversion efficiency of 30 % close to the theoretical limit of about 40 % at overall optical efficiency of the parametric Raman anti-Stokes generation of up to 3.5 % in calcite is obtained due to realization of tangential phase matching insensitive to the angular mismatch.

  9. Low-cost coherent UDWDM-PON by hybrid DBPSK/ASK-2 modulation

    Science.gov (United States)

    Li, Yuan; Deng, Zhuanhua; Hu, Rong; li, Cai; Li, Wei; Yuan, Zhilin; Yu, Shaohua

    2016-07-01

    The coherent ultra-dense wavelength division multiplexed passive optical network (UDWDM-PON) has been widely studied recently, in which the envelop detection based coherent reception of on-off keying (OOK) signal has been shown to possess both high receiver sensitivity and tolerance against laser linewidth/chirp. In order to increase the spectral efficiency (SE) to 2 bit/s/Hz, researchers formulated a hybrid DBPSK/ASK-2 modulation using the silicon Mach-Zehnder modulator (MZM), where both amplitude and phase modulation are employed. The experimental result shows that the proposed DBPSK/ASK-2 modulation is of better performance than PAM-4 at the same SE of 2 bit/s/Hz. When the low-cost silicon MZM and DFB laser of 4-MHz linewidth are employed, the receiver sensitivity of DBPSK/ASK-2 exceeds that of the PAM-4 by about 5.7 dB. This work can achieve about -46 dBm receiver sensitivity at 2.5 GBaud after transmission over 80-km standard single mode fiber (SSMF). The proposed DBPSK/ASK-2 modulation using low-cost silicon MZM and DFB laser is considered as a practical and reliable method for the future UDWDM-PON at the SE of 2 bit/s/Hz.

  10. White-light emission by phonon assisted coherent mixing of excitons in Au8-CdS hybrid nanorods

    Science.gov (United States)

    Rath, S.; Halder, O.; Pradhani, A.; Satpati, B.; Maity, A.; Chini, T. K.; Gogurla, N.; Ray, S. K.

    2016-12-01

    Gold cluster (Au8) coated CdS hybrid nanorods (HNRs), synthesized using a sonication assisted assembly route, exhibit phonon assisted coherent mixing of excitons. As observed from optical absorption, Raman scattering, x-ray diffraction and transmission electron microscopic studies, the Au8 modulates the crystal—and electronic—structure of the CdS nanorods, effecting enhancement of exciton-phonon (e-p) interactions. The e-p interaction and entropy effect mediated phase matching of the excitonic transitions, leading—via cooperative and coherent mixing of the excitons’ color—to the emission of white light, has been confirmed from room temperature and time resolved photoluminescence measurements.

  11. A new real-time non-coherent to coherent light image converter - The hybrid field effect liquid crystal light valve

    Science.gov (United States)

    Grinberg, J.; Jacobson, A.; Bleha, W.; Miller, L.; Fraas, L.; Boswell, D.; Myer, G.

    1975-01-01

    A new, high-performance device has been developed for application to real-time coherent optical data processing. The new device embodies a CdS photoconductor, a CdTe light-absorbing layer, a dielectric mirror, and a liquid crystal layer sandwiched between indium-tin-oxide transparent electrodes deposited on optical quality glass flats. The noncoherent image is directed onto the photoconductor; this reduces the impedance of the photoconductor, thereby switching the ac voltage that is impressed across the electrodes onto the liquid crystal to activate the device. The liquid crystal is operated in a hybrid field effect mode. It utilizes the twisted nematic effect to create a dark off-state and the optical birefringence effect to create the bright on-state. The liquid crystal modulates the polarization of the coherent read-out light so an analyzer must be used to create an intensity modulated output beam.

  12. A new real-time non-coherent to coherent light image converter - The hybrid field effect liquid crystal light valve

    Science.gov (United States)

    Grinberg, J.; Jacobson, A.; Bleha, W.; Miller, L.; Fraas, L.; Boswell, D.; Myer, G.

    1975-01-01

    A new, high-performance device has been developed for application to real-time coherent optical data processing. The new device embodies a CdS photoconductor, a CdTe light-absorbing layer, a dielectric mirror, and a liquid crystal layer sandwiched between indium-tin-oxide transparent electrodes deposited on optical quality glass flats. The noncoherent image is directed onto the photoconductor; this reduces the impedance of the photoconductor, thereby switching the ac voltage that is impressed across the electrodes onto the liquid crystal to activate the device. The liquid crystal is operated in a hybrid field effect mode. It utilizes the twisted nematic effect to create a dark off-state and the optical birefringence effect to create the bright on-state. The liquid crystal modulates the polarization of the coherent read-out light so an analyzer must be used to create an intensity modulated output beam.

  13. Coherent Ro-vibrational Revivals in a Thermal Molecular Ensemble

    CERN Document Server

    Bitter, Martin; Milner, Valery

    2012-01-01

    We report an experimental and theoretical study of the evolution of vibrational coherence in a thermal ensemble of nitrogen molecules. Rotational dephasing and rephasing of the vibrational coherence is detected by coherent anti-Stokes Raman scattering. The existence of ro-vibrational coupling and the discrete energy spectrum of the rotational bath lead to a whole new class of full and fractional ro-vibrational revivals. Following the rich ro-vibrational dynamics on a nanosecond time scale with sub-picosecond time resolution enables us to determine the second-order ro-vibrational constant $gamma_e$ and assess new possibilities of controlling decoherence.

  14. Double-clad hollow core photonic crystal fiber for coherent Raman endoscope.

    Science.gov (United States)

    Brustlein, Sophie; Berto, Pascal; Hostein, Richard; Ferrand, Patrick; Billaudeau, Cyrille; Marguet, Didier; Muir, Alistair; Knight, Jonathan; Rigneault, Hervé

    2011-06-20

    Performing label free coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) in endoscope imaging is a challenge, with huge potential clinical benefit. To date, this goal has remained inaccessible because of the inherent coherent Raman noise that is generated in the fiber itself. By developing double-clad hollow core photonic crystal fiber, we demonstrate coherent anti-Stokes Raman scattering and stimulated Raman scattering in an 'endoscope-like' scheme. Both the excitation beams and the collected CARS and SRS signals travel through the same fiber. No CARS and SRS signals are generated within the hollow core fiber even for temporally overlapping pump and Stokes beams, leading to excellent image quality. The CARS and SRS signals generated in the sample are coupled back into a high numerical aperture multimode cladding surrounding the central photonic crystal cladding. We demonstrate this scheme by imaging molecular vibrational bonds of organic crystal deposited on a glass surface.

  15. CARS (Coherent Anti-Stokes Raman Scattering) Spectroscopy of the Reaction Zone of Methane-Nitrous Oxide and RDX Propellant Flames.

    Science.gov (United States)

    1986-01-01

    initio calculations ( Fendell et al., ref 29) and constants (Dabrowski, et al., ref 30) derived from the BEu <--X’ Eg+ and C flu <-- X Eg+ band of H2 (Haw...Harris, Combustion and Flame, vol 53, 1983, p I3. 5. K. Aron, L. H. Harris, and J. Fendell , Applied Optics, vol 22, 1983, p 36U4. h. K. Aron and L. E...vol 92, 1982, p 246. 29. J. FendelL , L. E. Harris, and K. Aron, "Theoretical Calculation of H2 CARS Spectra for Propellant Flames," Technical Report

  16. Plasmon-enhanced light harvesting of chlorophylls on near-percolating silver films via one-photon anti-Stokes upconversion.

    Science.gov (United States)

    Wang, Ya-Lan; Nan, Fan; Liu, Xiao-Li; Zhou, Li; Peng, Xiao-Niu; Zhou, Zhang-Kai; Yu, Ying; Hao, Zhong-Hua; Wu, Yan; Zhang, Wei; Wang, Qu-Quan; Zhang, Zhenyu

    2013-01-01

    There exists a wealth of means of efficient utilization of solar energy in nature, with photosynthesis of chlorophylls as a prime example. Separately, artificially structured plasmonic materials are versatile in light harvesting and energy conversion. Using a simple and scalable design of near-percolating silver nanostructures, we demonstrate that the light-harvesting efficiency of chlorophylls can be drastically enhanced by tuning the plasmon frequency of the constituent silver nanoparticles to coincide with the maximal photon flux of sunlight. In particular, we show that the photon upconversion efficiency can be readily enhanced by over 20 folds, with the room-temperature fluorescence quantum yield increased by a factor of 2.63. The underlying mechanism for the upconversion enhancement is attributed to a one-electron-per-photon anti-Stokes process, involving absorption of a characteristic phonon mode of the chlorophylls. These findings suggest that chlorophylls can serve as molecular building blocks for high-efficiency light harvesting and solar energy conversion.

  17. Stokes and anti-Stokes photoluminescence towards five different In-x(Al0.17Ga0.83)(1-x)As/Al0.17Ga0.83As quantum wells

    DEFF Research Database (Denmark)

    Machida, S.; Tadakuma, T.; Satake, A.

    2005-01-01

    Stokes and anti-Stokes photoluminescence (AS-PL) has been investigated in a step-graded Inx(Al0.17Ga0.83)1–xAs/Al0.17Ga0.83As quantum-well (QW) heterostructure consisting of five QWs with different x values. Stokes PL spectra of this sample show a significant difference in PL intensity between...

  18. Tuning of near-infrared-to-near-infrared luminescence from one-photon to two-photon anti-Stokes shift in Casub>3sub>Gasub>2-sub> sub>xsub>Crsub>xsub>Gesub>3sub>Osub>12sub> via varying Cr3+ content.

    Science.gov (United States)

    Lin, Huihong; Yu, Ting; Bai, Gongxun; Zhang, Qinyuan; Hao, Jianhua

    2017-02-15

    Near-infrared-to-near-infrared (NIR-to-NIR) anti-Stokes luminescence from Cr3+ singly doped Casub>3sub>Gasub>2sub>Gesub>3sub>Osub>12sub> (CGGG) occurs under the excitation of an 808 nm diode laser. The anti-Stokes processes vary from one photon to two photon, depending on the Cr3+ content (x) in Casub>3sub>Gasub>2-xsub>Crsub>xsub>Gesub>3sub>Osub>12sub>. The results suggest that phonon-assisted anti-Stokes excitation and cooperative energy transfer are involved in the observed upconversion (UC) processes of CGGG:Cr3+. The relevant Cr3+-doping-concentration-dependent NIR-to-NIR anti-Stokes luminescent mechanism, either one-photon or two-photon UC, is investigated. Such an observation on modulating the UC process via varying the doping concentration is helpful in broadening the understanding of UC phenomena.

  19. Reconfigurable Digital Coherent Receiver for Hybrid Optical Fiber/Wireless Metro-Access Networks

    DEFF Research Database (Denmark)

    Arlunno, Valeria; Guerrero Gonzalez, Neil; Caballero Jambrina, Antonio;

    Single reconfigurable DSP coherent receiver is experimentally demonstrated for mixed-format and bit-rates including QPSK, OFDM, IR-UWB for wireline and wireless signal types. Successful transmission and detection over a deployed fiber link is achieved.......Single reconfigurable DSP coherent receiver is experimentally demonstrated for mixed-format and bit-rates including QPSK, OFDM, IR-UWB for wireline and wireless signal types. Successful transmission and detection over a deployed fiber link is achieved....

  20. Split-probe hybrid femtosecond/picosecond rotational CARS for time-domain measurement of S-branch Raman linewidths within a single laser shot.

    Science.gov (United States)

    Patterson, Brian D; Gao, Yi; Seeger, Thomas; Kliewer, Christopher J

    2013-11-15

    We introduce a multiplex technique for the single-laser-shot determination of S-branch Raman linewidths with high accuracy and precision by implementing hybrid femtosecond (fs)/picosecond (ps) rotational coherent anti-Stokes Raman spectroscopy (CARS) with multiple spatially and temporally separated probe beams derived from a single laser pulse. The probe beams scatter from the rotational coherence driven by the fs pump and Stokes pulses at four different probe pulse delay times spanning 360 ps, thereby mapping collisional coherence dephasing in time for the populated rotational levels. The probe beams scatter at different folded BOXCARS angles, yielding spatially separated CARS signals which are collected simultaneously on the charge coupled device camera. The technique yields a single-shot standard deviation (1σ) of less than 3.5% in the determination of Raman linewidths and the average linewidth values obtained for N(2) are within 1% of those previously reported. The presented technique opens the possibility for correcting CARS spectra for time-varying collisional environments in operando.

  1. Hybrid quantum repeater based on dispersive CQED interactions between matter qubits and bright coherent light

    CERN Document Server

    Ladd, T D; Nemoto, K; Munro, W J; Yamamoto, Y; Ladd, Thaddeus D.; Loock, Peter van; Nemoto, Kae; Munro, William J.; Yamamoto, Yoshihisa

    2006-01-01

    We describe a system for long-distance distribution of quantum entanglement, in which coherent light with large average photon number interacts dispersively with single, far-detuned atoms or semiconductor impurities in optical cavities. Entanglement is heralded by homodyne detection using a second bright light pulse for phase reference. The use of bright pulses leads to a high success probability for the generation of entanglement, at the cost of a lower initial fidelity. This fidelity may be boosted by entanglement purification techniques, implemented with the same physical resources. The need for more purification steps is well compensated for by the increased probability of success when compared to heralded entanglement schemes using single photons or weak coherent pulses with realistic detectors. The principle cause of the lower initial fidelity is fiber loss; however, spontaneous decay and cavity losses during the dispersive atom/cavity interactions can also impair performance. We show that these effects...

  2. Femtosecond coherent Raman spectroscopy and its application to porphyrins.

    Science.gov (United States)

    Schmitt, M; Heid, M; Schlücker, S; Kiefer, W

    2002-01-01

    The results on femtosecond time-resolved coherent anti-Stokes Raman scattering (CARS) experiments for the analysis and control of ground state vibrational dynamics of porphyrin systems are briefly reviewed. By detecting the spectrum of the transient CARS signal, a detailed mapping of the dynamics initiated by the stimulated Raman pump process is achieved. The method yields the dephasing behavior and spectral information of the investigated system at the same time. The different contributions to the ground state vibrational dynamics are selected by changing the direction of the CARS signal analyzer in the polarization arrangement used.

  3. Quadrature phase shift keying coherent state discrimination via a hybrid receiver

    DEFF Research Database (Denmark)

    Müller, C. R.; Castaneda, Mario A. Usuga; Wittmann, C.;

    2012-01-01

    We propose and experimentally demonstrate a near-optimal discrimination scheme for the quadrature phase shift keying (QPSK) protocol. We show in theory that the performance of our hybrid scheme is superior to the standard scheme—heterodyne detection—for all signal amplitudes and underpin the pred...

  4. Mapping coherence in measurement via full quantum tomography of a hybrid optical detector

    CERN Document Server

    Zhang, Lijian; Datta, Animesh; Puentes, Graciana; Lundeen, Jeff S; Jin, Xian-Min; Smith, Brian J; Plenio, Martin B; Walmsley, Ian A

    2012-01-01

    Quantum states and measurements exhibit wave-like --- continuous, or particle-like --- discrete, character. Hybrid discrete-continuous photonic systems are key to investigating fundamental quantum phenomena, generating superpositions of macroscopic states, and form essential resources for quantum-enhanced applications, e.g. entanglement distillation and quantum computation, as well as highly efficient optical telecommunications. Realizing the full potential of these hybrid systems requires quantum-optical measurements sensitive to complementary observables such as field quadrature amplitude and photon number. However, a thorough understanding of the practical performance of an optical detector interpolating between these two regions is absent. Here, we report the implementation of full quantum detector tomography, enabling the characterization of the simultaneous wave and photon-number sensitivities of quantum-optical detectors. This yields the largest parametrization to-date in quantum tomography experiments...

  5. Optical parametric oscillator-based light source for coherent Raman scattering microscopy: practical overview

    Science.gov (United States)

    Brustlein, Sophie; Ferrand, Patrick; Walther, Nico; Brasselet, Sophie; Billaudeau, Cyrille; Marguet, Didier; Rigneault, Hervé

    2011-02-01

    We present the assets and constraints of using optical parametric oscillators (OPOs) to perform point scanning nonlinear microscopy and spectroscopy with special emphasis on coherent Raman spectroscopy. The difterent possible configurations starting with one OPO and two OPOs are described in detail and with comments that are intended to be practically useful for the user. Explicit examples on test samples such as nonlinear organic crystal, polystyrene beads, and fresh mouse tissues are given. Special emphasis is given to background-free coherent Raman anti-Stokes scattering (CARS) imaging, including CARS hyperspectral imaging in a fully automated mode with commercial OPOs.

  6. Coherent optical spectroscopy in a biological semiconductor quantum dot-DNA hybrid system

    Science.gov (United States)

    2012-01-01

    We theoretically investigate coherent optical spectroscopy of a biological semiconductor quantum dot (QD) coupled to DNA molecules. Coupling with DNAs, the linear optical responses of the peptide QDs will be enhanced significantly in the simultaneous presence of two optical fields. Based on this technique, we propose a scheme to measure the vibrational frequency of DNA and the coupling strength between peptide QD and DNA in all-optical domain. Distinct with metallic quantum dot, biological QD is non-toxic and pollution-free to environment, which will contribute to clinical medicine experiments. This article leads people to know more about the optical behaviors of DNAs-quantum dot system, with the currently popular pump-probe technique. PMID:22340277

  7. Coherent optical spectroscopy in a biological semiconductor quantum dot-DNA hybrid system.

    Science.gov (United States)

    Li, Jin-Jin; Zhu, Ka-Di

    2012-02-16

    We theoretically investigate coherent optical spectroscopy of a biological semiconductor quantum dot (QD) coupled to DNA molecules. Coupling with DNAs, the linear optical responses of the peptide QDs will be enhanced significantly in the simultaneous presence of two optical fields. Based on this technique, we propose a scheme to measure the vibrational frequency of DNA and the coupling strength between peptide QD and DNA in all-optical domain. Distinct with metallic quantum dot, biological QD is non-toxic and pollution-free to environment, which will contribute to clinical medicine experiments. This article leads people to know more about the optical behaviors of DNAs-quantum dot system, with the currently popular pump-probe technique.

  8. Hybrid fs/ps CARS for Sooting and Particle-laden Flames [PowerPoint

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmeister, Kathryn N. Gabet; Guildenbecher, Daniel Robert; Kearney, Sean P.

    2016-01-01

    We report the application of ultrafast rotational coherent anti-Stokes Raman scattering (CARS) for temperature and relative oxygen concentration measurements in the plume emanating from a burning aluminized ammonium perchlorate propellant strand. Combustion of these metal-based propellants is a particularly hostile environment for laserbased diagnostics, with intense background luminosity, scattering and beam obstruction from hot metal particles that can be as large as several hundred microns in diameter. CARS spectra that were previously obtained using nanosecond pulsed lasers in an aluminumparticle- seeded flame are examined and are determined to be severely impacted by nonresonant background, presumably as a result of the plasma formed by particulateenhanced laser-induced breakdown. Introduction of fs/ps laser pulses enables CARS detection at reduced pulse energies, decreasing the likelihood of breakdown, while simultaneously providing time-gated elimination of any nonresonant background interference. Temperature probability densities and temperature/oxygen correlations were constructed from ensembles of several thousand single-laser-shot measurements from the fs/ps rotational CARS measurement volume positioned within 3 mm or less of the burning propellant surface. Preliminary results in canonical flames are presented using a hybrid fs/ps vibrational CARS system to demonstrate our progress towards acquiring vibrational CARS measurements for more accurate temperatures in the very high temperature propellant burns.

  9. Hybrid fs/ps CARS for Sooting and Particle-laden Flames

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmeister, Kathryn N. Gabet; Guildenbecher, Daniel Robert; Kearney, Sean P.

    2015-12-01

    We report the application of ultrafast rotational coherent anti-Stokes Raman scattering (CARS) for temperature and relative oxygen concentration measurements in the plume emanating from a burning aluminized ammonium perchlorate propellant strand. Combustion of these metal-based propellants is a particularly hostile environment for laserbased diagnostics, with intense background luminosity, scattering and beam obstruction from hot metal particles that can be as large as several hundred microns in diameter. CARS spectra that were previously obtained using nanosecond pulsed lasers in an aluminumparticle- seeded flame are examined and are determined to be severely impacted by nonresonant background, presumably as a result of the plasma formed by particulateenhanced laser-induced breakdown. Introduction of fs/ps laser pulses enables CARS detection at reduced pulse energies, decreasing the likelihood of breakdown, while simultaneously providing time-gated elimination of any nonresonant background interference. Temperature probability densities and temperature/oxygen correlations were constructed from ensembles of several thousand single-laser-shot measurements from the fs/ps rotational CARS measurement volume positioned within 3 mm or less of the burning propellant surface. Preliminary results in canonical flames are presented using a hybrid fs/ps vibrational CARS system to demonstrate our progress towards acquiring vibrational CARS measurements for more accurate temperatures in the very high temperature propellant burns.

  10. Hybrid Elastin-like Polypeptide–Polyethylene Glycol (ELP-PEG) Hydrogels with Improved Transparency and Independent Control of Matrix Mechanics and Cell Ligand Density

    Science.gov (United States)

    2015-01-01

    Hydrogels have been developed as extracellular matrix (ECM) mimics both for therapeutic applications and basic biological studies. In particular, elastin-like polypeptide (ELP) hydrogels, which can be tuned to mimic several biochemical and physical characteristics of native ECM, have been constructed to encapsulate various types of cells to create in vitro mimics of in vivo tissues. However, ELP hydrogels become opaque at body temperature because of ELP’s lower critical solution temperature behavior. This opacity obstructs light-based observation of the morphology and behavior of encapsulated cells. In order to improve the transparency of ELP hydrogels for better imaging, we have designed a hybrid ELP-polyethylene glycol (PEG) hydrogel system that rapidly cross-links with tris(hydroxymethyl) phosphine (THP) in aqueous solution via Mannich-type condensation. As expected, addition of the hydrophilic PEG component significantly improves the light transmittance. Coherent anti-Stokes Raman scattering (CARS) microscopy reveals that the hybrid ELP-PEG hydrogels have smaller hydrophobic ELP aggregates at 37 °C. Importantly, this hydrogel platform enables independent tuning of adhesion ligand density and matrix stiffness, which is desirable for studies of cell–matrix interactions. Human fibroblasts encapsulated in these hydrogels show high viability (>98%) after 7 days of culture. High-resolution confocal microscopy of encapsulated fibroblasts reveals that the cells adopt a more spread morphology in response to higher RGD ligand concentrations and softer gel mechanics. PMID:25111283

  11. Coupled cavity QED for coherent control of photon transmission (I): Green function approach for hybrid systems with two-level doping

    CERN Document Server

    Hu, F M; Sun, C P; Zhou, L; Shi, Tao; Zhou, Lan

    2006-01-01

    This is the first one of a series of our papers theoretically studying the coherent control of photon transmission along the coupled resonator optical waveguide (CROW) by doping artificial atoms for various hybrid structures. We will provide the several approaches correspondingly based on Green function, the mean field method and spin wave theory et al. In the present paper we adopt the two-time Green function approach to study the coherent transmission photon in a CROW with homogeneous couplings, each cavity of which is doped by a two-level artificial atom. We calculate the two-time correlation function for photon in the weak-coupling case. Its poles predict the exact dispersion relation, which results in the group velocity coherently controlled by the collective excitation of the doping atoms. We emphasize the role of the population inversion of doping atoms induced by some polarization mechanism.

  12. Coherent Raman spectro-imaging with laser frequency combs

    CERN Document Server

    Ideguchi, Takuro; Bernhardt, Birgitta; Guelachvili, Guy; Picqué, Nathalie; Hänsch, Theodor W

    2013-01-01

    Optical spectroscopy and imaging of microscopic samples have opened up a wide range of applications throughout the physical, chemical, and biological sciences. High chemical specificity may be achieved by directly interrogating the fundamental or low-lying vibrational energy levels of the compound molecules. Amongst the available prevailing label-free techniques, coherent Raman scattering has the distinguishing features of high spatial resolution down to 200 nm and three-dimensional sectioning. However, combining fast imaging speed and identification of multiple - and possibly unexpected- compounds remains challenging: existing high spectral resolution schemes require long measurement times to achieve broad spectral spans. Here we overcome this difficulty and introduce a novel concept of coherent anti-Stokes Raman scattering (CARS) spectro-imaging with two laser frequency combs. We illustrate the power of our technique with high resolution (4 cm-1) Raman spectra spanning more than 1200 cm-1 recorded within le...

  13. 光子晶体光纤中高效的反斯托克斯信号产生%High efficient anti-Stokes signal conversion in photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    申向伟; 余重秀; 桑新柱; 苑金辉; 韩颖; 夏长明; 侯蓝田; 饶芬; 夏民; 尹霄丽

    2012-01-01

    基于四波混频的反斯托克斯变换,被广泛应用于短波辐射高分辨率成像以及直接激发分子的电子跃迁等方面.为了实现更加高效的反斯托克斯变换,利用中心波长为810 nm脉冲宽度为120 fs的钛蓝宝石(Ti:sapphire)飞秒激光器作为抽运光源,在长度为0.5 m和3 m的光子晶体光纤中分别实现了高阶模和基膜的简并四波混频.实验中,采用的光子晶体光纤的零色散波长在820 nm附近.在基模相位匹配条件下,在560 nm附近实现了高效地反斯托克斯信号的产生,反斯托克斯信号与残余抽运信号的最大功率比为33:1;反斯托克斯信号和斯托克斯信号的最大功率比25:1;反斯托克斯信号最大功率转换效率P_a/P_(p0)为34%.抽运波长从790 nm逐渐增加到810 nm过程中,在长为3 m的光子晶体光纤中相位从不匹配状态转化为高阶模匹配状态后,再转化为基模匹配状态.通过实验研究得出了相位匹配程度随抽运功率、波长和光纤长度的变化规律,同时分析了造成理论计算与实验结果存在差异的主要因素.本文为研究在光子晶体光纤基模中实现相位匹配和产生高效反斯托克斯信号提供了理论和实验依据.%The anti-Stokes frequency conversion based on four-wave mixing(FWM) has been widely used to generate short-wavelength radiation for high resolution imaging,direct excitation of electronic molecular transitions,and so on.For achieving more effective anti- Stokes conversion,we use the Ti:sapphire laser with a central wavelength of 810 nm and a pulse width of 120 fs as a pump source,and the degenerated FWMs of the higher mode and the fundamental mode are achieved respectively in 0.5 m long and 3 m long photonic crystal fibers(PCFs) with a zero dispersion wavelength of fundamental mode around 820nm in our experiment.The anti-Stokes signals around 560nm are generated efficiently at the fundamental phase matching.The maximum

  14. An Implementation of the Deutsch-Jozsa Algorithm on Molecular Vibronic Coherences Through Four-Wave Mixing a Theoretical Study

    CERN Document Server

    Bihary, Z; Lidar, D A; Apkarian, V A; Bihary, Zsolt; Glenn, David R.; Lidar, Daniel A.

    2002-01-01

    Time-Frequency Resolved Coherent Anti-Stokes Raman Scattering (TFRCARS) was recently proposed as a means to implement quantum logic using the molecular ro-vibrational manifold as a quantum register [R. Zadoyan et al., Chem. Phys. 266, 323 (2001)]. We give a concrete example of how this can be accomplished through an illustrative algorithm that solves the Deutsch-Jozsa problem. We use realistic molecular parameters to recognize that, as the problem size expands, shaped pulses must be tailored to maintain fidelity of the algorithm.

  15. Coherent control of optical absorption and the energy transfer pathway of an infrared quantum dot hybridized with a VO2 nanoparticle

    Science.gov (United States)

    Hatef, Ali; Zamani, Naser; Johnston, William

    2017-04-01

    We systematically investigate the optical response of a semiconductor quantum dot (QD) hybridized with a vanadium dioxide nanoparticle (VO2NP) in the infrared (IR) region. The VO2NP features a semiconductor to metal phase change characteristic below and above a critical temperature that leads to an abrupt change in the particle’s optical properties. This feature means that the QD-VO2NP hybrid system can support the coherent coupling of exciton-polaritons and exciton-plasmon polaritons in the semiconductor and metal phases of the VO2NP, respectively. In our calculations, the VO2NP phase transition is modelled with a filling fraction (f), representing the fraction of the VO2NP in the metallic phase. The phase transition is driven by the hybrid system’s interaction with a continuous wave (CW) IR laser field. In this paper, we show how control over the filling fraction results in the enhancement or suppression of the QD’s linear absorption. These variations in the QD absorption is due to dramatic changes in the effective local field experienced by the QD and the non-radiative energy transfer from the QD to the VO2NP. The presented results have the potential to be applied to the design of thermal sensors at the nanoscale.

  16. Entanglement swapping and teleportation based on cavity QED method using the nonlinear atom-field interaction: Cavities with a hybrid of coherent and number states

    Science.gov (United States)

    Pakniat, R.; Tavassoly, M. K.; Zandi, M. H.

    2017-01-01

    In this paper, we outline a scheme for entanglement swapping based on the concept of cavity QED. The atom-field entangled state in our study is produced in the nonlinear regime. In this scheme, the exploited cavities are prepared in a hybrid entangled state (a combination of coherent and number states) and the swapping process is investigated using two different methods, i.e., detecting and Bell-state measurement methods through the cavity QED. Then, we make use of the atom-field entangled state obtained by detecting method to show that how the atom-atom entanglement as well as atomic and field states teleportation can be achieved with complete fidelity.

  17. Direct observation of the cyclic dimer in liquid acetic acid by probing the C=O vibration with ultrafast coherent Raman spectroscopy.

    Science.gov (United States)

    Lütgens, Matthias; Friedriszik, Frank; Lochbrunner, Stefan

    2014-09-01

    We present a comparison of spontaneous Raman and ultrafast coherent anti-Stokes Raman scattering (CARS) spectra of the C=O vibration of liquid acetic acid. The former technique cannot clearly reveal the number of contributions in the spectrum. However, the additional time and spectrally resolved CARS experiment supports strictly the existence of four modes, which proves the coexistence of more than one H-bonded configuration in liquid acetic acid. A comparably slowly dephasing mode which is obscured by a broad band in the linear Raman spectrum is assigned to the cyclic dimer and can be observed freed from all other contributions by ultrafast CARS.

  18. Phase-shift effect of amplitude spread function on spectrum and image formation in coherent Raman scattering microspectroscopy.

    Science.gov (United States)

    Fukutake, Naoki

    2016-03-01

    Coherent Raman scattering microspectroscopy, which includes coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) microspectroscopy, permits label-free hyperspectral imaging. We report the theoretical study of the phase-shift effect of the impulse response function on the spectral and image-forming properties of coherent Raman scattering microspectroscopy. We show that the spectrum and image are influenced by not only the NA of objective for excitation (NA(ex)) but also that for signal collection (NA(col)), in association with the phase-shift effect. We discuss that, under the condition NA(ex)≠NA(col), both the spectrum and the image become deformed by the phase-shift effect, which can be applied to the direct measurement of the imaginary part of the nonlinear susceptibility in CARS spectroscopy. We point out that, even in SRS microscopy, the nonresonant background can contribute to the image formation and cause the artifact in the image.

  19. Quantification of volumetric cerebral blood flow using hybrid laser speckle contract and optical coherence tomography (Conference Presentation)

    Science.gov (United States)

    Valim, Niksa; Dunn, Andrew K.

    2016-03-01

    Studying neurovascular blood flow function in cerebrovascular activities requires accurate visualization and characterization of blood flow volume as well as the dynamics of blood cells in microcirculation. In this study, we present a novel integration of laser speckle contrast imaging (LSCI) and spectral domain optical coherence tomography (SD-OCT) for rapid volumetric imaging of blood flow in cortical capillaries. LSCI uses the illumination of wide-field near infrared light (NIR) and monitors back scattered light to characterize the relative dynamics of blood flow in microcirculation. Absolute measurement of blood cells and blood volume requires high-resolution volumetric structural information. SD-OCT system uses coherence gating to measure scattered light from a small volume within high structural resolution. The structural imaging system rapidly assesses large number of capillaries for spatio-temporal tracking of red blood cells (RBC). A very fast-ultra resolution SD-OCT system was developed for imaging high-resolution volumetric samples. The system employed an ultra wideband light source (1310 ± 200 nm in wavelength) corresponding to an axial resolution of 3 micrometers in tissue. The spectrometer of the SD-OCT was customized for a maximum scanning rate of 147,000 line/s. We demonstrated a fast volumetric OCT angiography algorithm to visualize large numbers of vessels in a 2-mm deep sample volume. A LSCI system that has been developed previously in our group was integrated to the imaging system for the characterization of dynamic blood cells. The conjunction data from LSCI and SD-OCT systems imply the feasibility of accurate quantification of absolute cortical blood flow.

  20. Hybrid POD-FFT analysis of nonlinear evolving coherent structures of DNS wavepacket in laminar-turbulent transition

    Science.gov (United States)

    Kang, Kean Lee; Yeo, K. S.

    2017-08-01

    This paper concerns the study of direct numerical simulation data of a wavepacket in laminar turbulent transition in a Blasius boundary layer. The decomposition of this wavepacket into a set of "modes" (a basis that spans an approximate solution space) can be achieved in a wide variety of ways. Two well-known tools are the fast Fourier transform (FFT) and the proper orthogonal decomposition (POD). To synergize the strengths of both methods, a hybrid POD-FFT is pioneered, using the FFT as a tool for interpreting the POD modes. The POD-FFT automatically identifies well-known fundamental, subharmonic, and Klebanoff modes in the flow, even though it is blind to the underlying physics. Moreover, the POD-FFT further separates the subharmonic content of the wavepacket into three fairly distinct parts: a positively detuned mode resembling a Lambda-vortex, a Craik-type tuned mode, and a Herbert-type positive-negative detuned mode pair, in decreasing order of energy. This distinction is less widely recognized, but it provides a possible explanation for the slightly positively detuned subharmonic mode often observed in previous experiments and simulations.

  1. Cavity-assisted measurement and coherent control of collective atomic spin oscillators

    CERN Document Server

    Kohler, Jonathan; Schreppler, Sydney; Stamper-Kurn, Dan M

    2016-01-01

    We demonstrate continuous measurement and coherent control of the collective spin of an atomic ensemble undergoing Larmor precession in a high-finesse optical cavity. The coupling of the precessing spin oscillator to the cavity field yields phenomena similar to those observed in cavity optomechanics, including cavity amplification, damping, and optical spring shifts. These effects arise from autonomous optical feedback onto the atomic spin dynamics, conditioned by the cavity spectrum. We use this feedback to stabilize the spin in either its high- or low-energy state, where it achieves a steady-state temperature in equilibrium with measurement back-action. We measure the effective spin temperature from the asymmetry between the Stokes and anti-Stokes sidebands and show that, for sufficiently large Larmor frequency, such a feedback-stabilized spin ensemble remains in a nearly pure quantum state, in spite of continuous interaction with the probe field.

  2. Single-Beam Coherent Raman Spectroscopy and Microscopy via Spectral Notch Shaping

    CERN Document Server

    Katz, Ori; Grinvald, Eran; Silberberg, Yaron

    2010-01-01

    Raman spectroscopy is one of the key techniques in the study of vibrational modes and molecular structures. In Coherent Anti-Stokes Raman Scattering (CARS) spectroscopy, a molecular vibrational spectrum is resolved via the third-order nonlinear interaction of pump, Stokes and probe photons, typically using a complex experimental setup with multiple beams and laser sources. Although CARS has become a widespread technique for label-free chemical imaging and detection of contaminants, its multi-source, multi-beam experimental implementation is challenging. In this work we present a simple and easily implementable scheme for performing single-beam CARS spectroscopy and microscopy using a single femtosecond pulse, shaped by a tunable narrowband notch filter. As a substitute for multiple sources, the single broadband pulse simultaneously provides the pump, Stokes and probe photons, exciting a broad band of vibrational levels. High spectroscopic resolution is obtained by utilizing a tunable spectral notch, shaped wi...

  3. Catching Conical Intersections in the Act; Monitoring Transient Electronic Coherences by Attosecond Stimulated X-Ray Raman Signals

    Science.gov (United States)

    Bennett, Kochise; Kowalewski, Markus; Dorfman, Konstantin; Mukamel, Shaul

    Conical intersections (CIs) dominate the pathways and outcomes of virtually all photochemical molecular processes. Despite extensive experimental and theoretical effort, CIs have not been directly observed yet and the experimental evidence is inferred from fast reaction rates and vibrational signatures. We show that short X-ray pulses can directly detect the passage through a CI with the adequate temporal and spectral sensitivity. The non-adiabatic coupling that exists in the region of a CI redistributes electronic population but also generates electronic coherence. This coherent oscillation can then be detected via a coherent Raman process that employs a composite femtosecond/attosecond X-ray pulse. This technique, dubbed Transient Redistribution of Ultrafast Electronic Coherences (TRUECARS) is reminiscent of Coherent Anti-Stokes Raman Spectroscopy (CARS) in that a coherent oscillation is set in motion and then monitored, but differs in that the dynamics is electronic (CARS generally observes nuclear dynamics) and the coherence is generated internally by passage through a region of non-adiabatic coupling rather than by an externally applied laser. Support provided by U.S. Department of Energy through Award No. DE-FG02-04ER15571, the National Science Foundation (Grant No CHE-1361516), and the Alexander von Humboldt foundation through the Feodor Lynen program.

  4. Nonclassical correlation between optical and microwave photons in a hybrid electro-optomechanical system

    Science.gov (United States)

    Xie, Hong; Chen, Xiang; Lin, Gongwei; Lin, Xiumin

    2016-10-01

    A scheme to correlate optical and microwave photons is proposed in a hybrid electro-optomechanical system, where mechanical resonator is coupled to both optical and microwave fields. Analytical and numerical simulation results show that the cross-correlation function between Stokes and anti-Stokes photons strongly violates the Cauchy-Schwarz inequality, which confirms the nonclassical correlation between the optical and microwave photons. It is worth noting that the nonclassical photon pairs with vast different wavelengths, which may be useful for quantum communication, are generated under the experimentally accessible weak coupling limit rather than single-photon strong coupling regime. In addition, the protocol provides a possible route to combine the respective advantages of optical photons, microwave photons, and phonons in a hybrid electro-optomechanical system.

  5. Free-space coherent optical communication with orbital angular, momentum multiplexing/demultiplexing using a hybrid 3D photonic integrated circuit.

    Science.gov (United States)

    Guan, Binbin; Scott, Ryan P; Qin, Chuan; Fontaine, Nicolas K; Su, Tiehui; Ferrari, Carlo; Cappuzzo, Mark; Klemens, Fred; Keller, Bob; Earnshaw, Mark; Yoo, S J B

    2014-01-13

    We demonstrate free-space space-division-multiplexing (SDM) with 15 orbital angular momentum (OAM) states using a three-dimensional (3D) photonic integrated circuit (PIC). The hybrid device consists of a silica planar lightwave circuit (PLC) coupled to a 3D waveguide circuit to multiplex/demultiplex OAM states. The low excess loss hybrid device is used in individual and two simultaneous OAM states multiplexing and demultiplexing link experiments with a 20 Gb/s, 1.67 b/s/Hz quadrature phase shift keyed (QPSK) signal, which shows error-free performance for 379,960 tested bits for all OAM states.

  6. Ex vivo and in vivo coherent Raman imaging of the peripheral and central nervous system

    Science.gov (United States)

    Huff, Terry Brandon

    A hallmark of nervous system disorders is damage or degradation of the myelin sheath. Unraveling the mechanisms underlying myelin degeneration and repair represent one of the great challenges in medicine. This thesis work details the development and utilization of advanced optical imaging methods to gain insight into the structure and function of myelin in both healthy and diseased states in the in vivo environment. This first part of this thesis discusses ex vivo studies of the effects of high-frequency stimulation of spinal tissues on the structure of the node of Ranvier as investigated by coherent anti-Stokes Raman scattering (CARS) imaging (manuscript submitted to Journal of Neurosciece). Reversible paranodal myelin retraction at the nodes of Ranvier was observed during 200 Hz electrical stimulation, beginning minutes after the onset and continuing for up to 10 min after stimulation was ceased. A mechanistic study revealed a Ca2+ dependent pathway: high-frequency stimulation induced paranodal myelin retraction via pathologic calcium influx into axons, calpain activation, and cytoskeleton degradation through spectrin break-down. Also, the construction of dual-scanning CARS microscope for large area mapping of CNS tissues is detailed (Optics Express, 2008, 16:19396-193409). A confocal scanning head equipped with a rotating polygon mirror provides high speed, high resolution imaging and is coupled with a motorized sample stage to generate high-resolution large-area images of mouse brain coronal section and guinea pig spinal cord cross section. The polygon mirror decreases the mosaic acquisition time significantly without reducing the resolution of individual images. The ex vivo studies are then extended to in vivo imaging of mouse sciatic nerve tissue by CARS and second harmonic generation (SHG) imaging (Journal of Microscopy, 2007, 225: 175-182). Following a minimally invasive surgery to open the skin, CARS imaging of myelinated axons and SHG imaging of the

  7. Electroencephalograpic coherence

    Directory of Open Access Journals (Sweden)

    Simon Brežan

    2004-08-01

    Full Text Available Different brain areas process various aspects of information in parallel as well as segregated way. It is not known, how is this information integrated into a unitary percept or action. The binding problem is one of the key problems in understanding brain function. Synchronized oscillatory activity of neurons is one possible mechanism of the functional integration of different communicating brain areas. The binding has been well-studied in the visual system, but it could also serve as a mechanism in visuomotor integration or functional coupling present with other brain processes and behavioural modes (perception, complex motor behaviour, selective attention, learning, working memory, etc.. Interregional synchronization of the electroencephalographic (EEG signal can be determined by EEG coherence analysis. In the article we present a research example of coherence changes in a visuomotor task. During this task, coherence between visual and motor brain areas increased. This might reflect functional coupling between those areas, but it could also be influenced by other cognitive processes (e.g. selective attention. Coherence analysis is suitable for studying integrative brain function. Because it measures only one of the possible mechanisms of integration, it offers promise especially when combined with other electrophysiological and functional imaging methods.

  8. Coherent amplified optical coherence tomography

    Science.gov (United States)

    Zhang, Jun; Rao, Bin; Chen, Zhongping

    2007-07-01

    A technique to improve the signal-to-noise ratio (SNR) of a high speed 1300 nm swept source optical coherence tomography (SSOCT) system was demonstrated. A semiconductor optical amplifier (SOA) was employed in the sample arm to coherently amplify the weak light back-scattered from sample tissue without increasing laser power illuminated on the sample. The image quality improvement was visualized and quantified by imaging the anterior segment of a rabbit eye at imaging speed of 20,000 A-lines per second. The theory analysis of SNR gain is given followed by the discussion on the technologies that can further improve the SNR gain.

  9. Coherence and Sense of Coherence

    DEFF Research Database (Denmark)

    Dau, Susanne

    2014-01-01

    Constraints in the implementation of models of blended learning can be explained by several causes, but in this paper, it is illustrated that lack of sense of coherence is a major factor of these constraints along with the referential whole of the perceived learning environments. The question...... of coherence is both related to conditional matters as learning environments, structure, clarity and linkage but also preconditioned matters and prerequisites among participants related to experiences and convenience. It is stressed that this calls for continuous assessment and reflections upon these terms...... and conditions if the student shall be able acquire the necessary competencies....

  10. Coherence, Pseudo-Coherence, and Non-Coherence.

    Science.gov (United States)

    Enkvist, Nils Erik

    Analysis of the factors that make a text coherent or non-coherent suggests that total coherence requires cohesion not only on the textual surface but on the semantic level as well. Syntactic evidence of non-coherence includes lack of formal agreement blocking a potential cross-reference, anaphoric and cataphoric references that do not follow their…

  11. Coherence and Sense of Coherence

    DEFF Research Database (Denmark)

    Dau, Susanne

    2014-01-01

    of coherence is both related to conditional matters as learning environments, structure, clarity and linkage but also preconditioned matters and prerequisites among participants related to experiences and convenience. It is stressed that this calls for continuous assessment and reflections upon these terms...... and conditions if the student shall be able acquire the necessary competencies....

  12. Nonlinear optical spectra having characteristics of Fano interferences in coherently coupled lowest exciton biexciton states in semiconductor quantum dots

    Directory of Open Access Journals (Sweden)

    Hideki Gotoh

    2014-10-01

    Full Text Available Optical nonlinear effects are examined using a two-color micro-photoluminescence (micro-PL method in a coherently coupled exciton-biexciton system in a single quantum dot (QD. PL and photoluminescence excitation spectroscopy (PLE are employed to measure the absorption spectra of the exciton and biexciton states. PLE for Stokes and anti-Stokes PL enables us to clarify the nonlinear optical absorption properties in the lowest exciton and biexciton states. The nonlinear absorption spectra for excitons exhibit asymmetric shapes with peak and dip structures, and provide a distinct contrast to the symmetric dip structures of conventional nonlinear spectra. Theoretical analyses with a density matrix method indicate that the nonlinear spectra are caused not by a simple coherent interaction between the exciton and biexciton states but by coupling effects among exciton, biexciton and continuum states. These results indicate that Fano quantum interference effects appear in exciton-biexciton systems at QDs and offer important insights into their physics.

  13. In vivo coherent Raman imaging of the melanomagenesis-associated pigment pheomelanin

    Science.gov (United States)

    Wang, Hequn; Osseiran, Sam; Igras, Vivien; Nichols, Alexander J.; Roider, Elisabeth M.; Pruessner, Joachim; Tsao, Hensin; Fisher, David E.; Evans, Conor L.

    2016-11-01

    Melanoma is the most deadly form of skin cancer with a yearly global incidence over 232,000 patients. Individuals with fair skin and red hair exhibit the highest risk for developing melanoma, with evidence suggesting the red/blond pigment known as pheomelanin may elevate melanoma risk through both UV radiation-dependent and -independent mechanisms. Although the ability to identify, characterize, and monitor pheomelanin within skin is vital for improving our understanding of the underlying biology of these lesions, no tools exist for real-time, in vivo detection of the pigment. Here we show that the distribution of pheomelanin in cells and tissues can be visually characterized non-destructively and noninvasively in vivo with coherent anti-Stokes Raman scattering (CARS) microscopy, a label-free vibrational imaging technique. We validated our CARS imaging strategy in vitro to in vivo with synthetic pheomelanin, isolated melanocytes, and the Mc1re/e, red-haired mouse model. Nests of pheomelanotic melanocytes were observed in the red-haired animals, but not in the genetically matched Mc1re/e; Tyrc/c (“albino-red-haired”) mice. Importantly, samples from human amelanotic melanomas subjected to CARS imaging exhibited strong pheomelanotic signals. This is the first time, to our knowledge, that pheomelanin has been visualized and spatially localized in melanocytes, skin, and human amelanotic melanomas.

  14. Universality of Coherent Raman Gain Suppression in Gas-Filled Broadband-Guiding Photonic Crystal Fibers

    Science.gov (United States)

    Hosseini, P.; Mridha, M. K.; Novoa, D.; Abdolvand, A.; Russell, P. St. J.

    2017-03-01

    As shown in the early 1960s, the gain in stimulated Raman scattering (SRS) is drastically suppressed when the rate of creation of phonons (via a pump-to-Stokes conversion) is exactly balanced by the rate of phonon annihilation (via a pump-to-anti-Stokes conversion). This occurs when the phonon coherence waves—synchronized vibrations of a large population of molecules—have identical propagation constants for both processes; i.e., they are phase-velocity matched. As recently demonstrated, hydrogen-filled photonic crystal fiber pumped in the vicinity of its zero-dispersion wavelength provides an ideal system for observing this effect. Here we report that Raman gain suppression is actually a universal feature of SRS in gas-filled hollow-core fibers and that it can strongly impair SRS even when the phase mismatch is high, particularly at high pump powers when it is normally assumed that nonlinear processes become more (not less) efficient. This counterintuitive result means that intermodal stimulated Raman scattering (for example, between LP01 and LP11 core modes) begins to dominate at high power levels. The results reported have important implications for fiber-based Raman shifters, amplifiers, or frequency combs, especially for operation in the ultraviolet, where the Raman gain is much higher.

  15. Searching for coherence in a correspondence world

    Directory of Open Access Journals (Sweden)

    Kathleen L. Mosier

    2009-03-01

    Full Text Available In this paper, I trace the evolution of the aircraft cockpit as an example of the transformation of a probabilistic environment into an ecological hybrid, that is, an environment characterized by both probabilistic and deterministic features and elements. In the hybrid ecology, the relationships among correspondence and coherence strategies and goals and cognitive tactics on the continuum from intuition to analysis become critically important. Intuitive tactics used to achieve correspondence in the physical world do not work in the electronic world. Rather, I make the case that judgment and decision making in a hybrid ecology requires extit{coherence} as the primary strategy to achieve extit{correspondence}, and that this process requires a shift in tactics from intuition toward analysis.

  16. SO(10)-GUT coherent baryogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Garbrecht, Bjoern [Institut fuer Theoretische Physik, Universitaet Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany)]. E-mail: b.garbrecht@thphys.uni-heidelberg.de; Prokopec, Tomislav [Institute for Theoretical Physics (ITF) and Spinoza Institute, Utrecht University, Leuvenlaan 4, Postbus 80.195, 3508 TD Utrecht (Netherlands)]. E-mail: t.prokopec@phys.uu.nl; Schmidt, Michael G. [Institut fuer Theoretische Physik, Universitaet Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany)]. E-mail: m.g.schmidt@thphys.uni-heidelberg.de

    2006-02-20

    A model for GUT baryogenesis, coherent baryogenesis within the framework of supersymmetric SO(10), is considered. In particular, we discuss the Barr-Raby model, where at the end of hybrid inflation charge asymmetries can be created through the time-dependent higgsino-gaugino mixing mass matrix. These asymmetries are processed to Standard Model matter through decays via nonrenormalizable (B-L)-violating operators. We find that a baryon asymmetry in accordance with observation can be generated. An appendix is devoted to provide useful formulas and concrete examples for calculations within SO(10)

  17. Cohering power of quantum operations

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Kaifeng, E-mail: bkf@zju.edu.cn [School of Mathematical Sciences, Zhejiang University, Hangzhou 310027 (China); Kumar, Asutosh, E-mail: asukumar@hri.res.in [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India); Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India); Zhang, Lin, E-mail: linyz@zju.edu.cn [Institute of Mathematics, Hangzhou Dianzi University, Hangzhou 310018 (China); Wu, Junde, E-mail: wjd@zju.edu.cn [School of Mathematical Sciences, Zhejiang University, Hangzhou 310027 (China)

    2017-05-18

    Highlights: • Quantum coherence. • Cohering power: production of quantum coherence by quantum operations. • Study of cohering power and generalized cohering power, and their comparison for differentmeasures of quantum coherence. • Operational interpretation of cohering power. • Bound on cohering power of a generic quantum operation. - Abstract: Quantum coherence and entanglement, which play a crucial role in quantum information processing tasks, are usually fragile under decoherence. Therefore, the production of quantum coherence by quantum operations is important to preserve quantum correlations including entanglement. In this paper, we study cohering power–the ability of quantum operations to produce coherence. First, we provide an operational interpretation of cohering power. Then, we decompose a generic quantum operation into three basic operations, namely, unitary, appending and dismissal operations, and show that the cohering power of any quantum operation is upper bounded by the corresponding unitary operation. Furthermore, we compare cohering power and generalized cohering power of quantum operations for different measures of coherence.

  18. Partially coherent imaging and spatial coherence wavelets

    CERN Document Server

    Castaneda, R

    2003-01-01

    A description of spatially partially coherent imaging based on the propagation of second order spatial coherence wavelets and marginal power spectra (Wigner distribution functions) is presented. In this dynamics, the spatial coherence wavelets will be affected by the system through its elementary transfer function. The consistency of the model with the both extreme cases of full coherent and incoherent imaging was proved. In the last case we obtained the classical concept of optical transfer function as a simple integral of the elementary transfer function. Furthermore, the elementary incoherent response function was introduced as the Fourier transform of the elementary transfer function. It describes the propagation of spatial coherence wavelets form each object point to each image point through a specific point on the pupil planes. The point spread function of the system was obtained by a simple integral of the elementary incoherent response function.

  19. On Longitudinal Spectral Coherence

    DEFF Research Database (Denmark)

    Kristensen, Leif

    1979-01-01

    It is demonstrated that the longitudinal spectral coherence differs significantly from the transversal spectral coherence in its dependence on displacement and frequency. An expression for the longitudinal coherence is derived and it is shown how the scale of turbulence, the displacement between...

  20. Complex fermion coherent states

    CERN Document Server

    Tyc, T; Sanders, B C; Oliver, W D; Tyc, Tomas; Hamilton, Brett; Sanders, Barry C.; Oliver, William D.

    2005-01-01

    Whereas boson coherent states provide an elegant, intuitive and useful representation, we show that the desirable features of boson coherent states do not carry over very well to fermion fields unless one is prepared to use exotic approaches such as Grassmann fields. Specifically, we identify four appealing properties of boson coherent states (eigenstate of annihilation operator, displaced vacuum state, preservation of product states under linear coupling, and factorization of correlators) and show that fermion coherent states, and approximations to fermion coherent states, defined over the complex field, do not behave well for any of these four criteria.

  1. Conditional Hybrid Nonclassicality

    Science.gov (United States)

    Agudelo, E.; Sperling, J.; Costanzo, L. S.; Bellini, M.; Zavatta, A.; Vogel, W.

    2017-09-01

    We derive and implement a general method to characterize the nonclassicality in compound discrete- and continuous-variable systems. For this purpose, we introduce the operational notion of conditional hybrid nonclassicality which relates to the ability to produce a nonclassical continuous-variable state by projecting onto a general superposition of discrete-variable subsystem. We discuss the importance of this form of quantumness in connection with interfaces for quantum communication. To verify the conditional hybrid nonclassicality, a matrix version of a nonclassicality quasiprobability is derived and its sampling approach is formulated. We experimentally generate an entangled, hybrid Schrödinger cat state, using a coherent photon-addition process acting on two temporal modes, and we directly sample its nonclassicality quasiprobability matrix. The introduced conditional quantum effects are certified with high statistical significance.

  2. Coherent Raman spectroscopy

    CERN Document Server

    Eesley, G L

    1981-01-01

    Coherent Raman Spectroscopy provides a unified and general account of the fundamental aspects of nonlinear Raman spectroscopy, also known as coherent Raman spectroscopy. The theoretical basis from which coherent Raman spectroscopy developed is described, along with its applications, utility, and implementation as well as advantages and disadvantages. Experimental data which typifies each technique is presented. This book is comprised of four chapters and opens with an overview of nonlinear optics and coherent Raman spectroscopy, followed by a discussion on nonlinear transfer function of matter

  3. Application Coherency Manager Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes an Application Coherency Manager that implements and manages the interdependencies of simulation, data, and platform information. It will...

  4. On -Coherent Endomorphism Rings

    Indian Academy of Sciences (India)

    Li-Xin Mao

    2008-11-01

    A ring is called right -coherent if every principal right ideal is finitely presented. Let $M_R$ be a right -module. We study the -coherence of the endomorphism ring of $M_R$. It is shown that is a right -coherent ring if and only if every endomorphism of $M_R$ has a pseudokernel in add $M_R; S$ is a left -coherent ring if and only if every endomorphism of $M_R$ has a pseudocokernel in add $M_R$. Some applications are given.

  5. Text Coherence in Translation

    Science.gov (United States)

    Zheng, Yanping

    2009-01-01

    In the thesis a coherent text is defined as a continuity of senses of the outcome of combining concepts and relations into a network composed of knowledge space centered around main topics. And the author maintains that in order to obtain the coherence of a target language text from a source text during the process of translation, a translator can…

  6. Reverse Coherent Information

    Science.gov (United States)

    García-Patrón, Raúl; Pirandola, Stefano; Lloyd, Seth; Shapiro, Jeffrey H.

    2009-05-01

    In this Letter we define a family of entanglement distribution protocols assisted by feedback classical communication that gives an operational interpretation to reverse coherent information, i.e., the symmetric counterpart of the well-known coherent information. This leads to the definition of a new entanglement distribution capacity that exceeds the unassisted capacity for some interesting channels.

  7. Understanding Causal Coherence Relations

    NARCIS (Netherlands)

    Mulder, G.

    2008-01-01

    The research reported in this dissertation focuses on the cognitive processes and representations involved in understanding causal coherence relations in text. Coherence relations are the meaning relations between the information units in the text, such as Cause-Consequence. These relations can be m

  8. VCSELs for coherent PON

    DEFF Research Database (Denmark)

    Jensen, Jesper Bevensee; Rodes, Roberto; Cheng, Ning;

    2015-01-01

    Recent advances and research on coherent technologies for access networks are discussed and put into context of user demands and standardization work.......Recent advances and research on coherent technologies for access networks are discussed and put into context of user demands and standardization work....

  9. VCSEL Based Coherent PONs

    DEFF Research Database (Denmark)

    Jensen, Jesper Bevensee; Rodes, Roberto; Caballero Jambrina, Antonio;

    2014-01-01

    We present a review of research performed in the area of coherent access technologies employing vertical cavity surface emitting lasers (VCSELs). Experimental demonstrations of optical transmission over a passive fiber link with coherent detection using VCSEL local oscillators and directly modula...

  10. Partially coherent ultrafast spectrography.

    Science.gov (United States)

    Bourassin-Bouchet, C; Couprie, M-E

    2015-03-06

    Modern ultrafast metrology relies on the postulate that the pulse to be measured is fully coherent, that is, that it can be completely described by its spectrum and spectral phase. However, synthesizing fully coherent pulses is not always possible in practice, especially in the domain of emerging ultrashort X-ray sources where temporal metrology is strongly needed. Here we demonstrate how frequency-resolved optical gating (FROG), the first and one of the most widespread techniques for pulse characterization, can be adapted to measure partially coherent pulses even down to the attosecond timescale. No modification of experimental apparatuses is required; only the processing of the measurement changes. To do so, we take our inspiration from other branches of physics where partial coherence is routinely dealt with, such as quantum optics and coherent diffractive imaging. This will have important and immediate applications, such as enabling the measurement of X-ray free-electron laser pulses despite timing jitter.

  11. NONLINEAR OPTICS: Coherent laser spectroscopy of matter utilizing waveguide structures

    Science.gov (United States)

    Chaus, A. I.; Yashkir, Yu N.

    1990-07-01

    Some features of CARS spectroscopy in waveguide structures are investigated theoretically taking into account stimulated Raman amplification of a weak pump wave in the field of a strong wave and allowing for the phase matching. A four-photon intermode coupling which occurs under amplification conditions results in energy diffusion between different modes. General expressions for the intensities of the pump waves undergoing stimulated amplification and for the anti-Stokes signal are derived and analyzed.

  12. Label-free in vivo analysis of intracellular lipid droplets in the oleaginous microalga Monoraphidium neglectum by coherent Raman scattering microscopy.

    Science.gov (United States)

    Jaeger, Daniel; Pilger, Christian; Hachmeister, Henning; Oberländer, Elina; Wördenweber, Robin; Wichmann, Julian; Mussgnug, Jan H; Huser, Thomas; Kruse, Olaf

    2016-10-21

    Oleaginous photosynthetic microalgae hold great promise as non-food feedstocks for the sustainable production of bio-commodities. The algal lipid quality can be analysed by Raman micro-spectroscopy, and the lipid content can be imaged in vivo in a label-free and non-destructive manner by coherent anti-Stokes Raman scattering (CARS) microscopy. In this study, both techniques were applied to the oleaginous microalga Monoraphidium neglectum, a biotechnologically promising microalga resistant to commonly applied lipid staining techniques. The lipid-specific CARS signal was successfully separated from the interfering two-photon excited fluorescence of chlorophyll and for the first time, lipid droplet formation during nitrogen starvation could directly be analysed. We found that the neutral lipid content deduced from CARS image analysis strongly correlated with the neutral lipid content measured gravimetrically and furthermore, that the relative degree of unsaturation of fatty acids stored in lipid droplets remained similar. Interestingly, the lipid profile during cellular adaption to nitrogen starvation showed a two-phase characteristic with initially fatty acid recycling and subsequent de novo lipid synthesis. This works demonstrates the potential of quantitative CARS microscopy as a label-free lipid analysis technique for any microalgal species, which is highly relevant for future biotechnological applications and to elucidate the process of microalgal lipid accumulation.

  13. Hybrid Baryons

    CERN Document Server

    Page, P R

    2003-01-01

    We review the status of hybrid baryons. The only known way to study hybrids rigorously is via excited adiabatic potentials. Hybrids can be modelled by both the bag and flux-tube models. The low-lying hybrid baryon is N 1/2^+ with a mass of 1.5-1.8 GeV. Hybrid baryons can be produced in the glue-rich processes of diffractive gamma N and pi N production, Psi decays and p pbar annihilation.

  14. The Puzzle of Coherence

    DEFF Research Database (Denmark)

    Andersen, Anne Bendix; Frederiksen, Kirsten; Beedholm, Kirsten;

    2016-01-01

    of coherence in treatment and patient pathways. The aim of our study is to explore the role of health care providers in furthering coherence. Our ambition is to identify areas for improvement or change of collaborative practice between health care providers in municipalities, hospitals and general practice...... initiatives in health care. The present study will generate new, valuable insight into the areas of cross-sectorial health care collaboration. Our findings may facilitate change in current practice and improve the quality and coherence in patient pathways of EPCD. The findings of this study will be useful...

  15. Coherent diffractive {rho} production

    Energy Technology Data Exchange (ETDEWEB)

    Hyett, N.M.; Tovey, S.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1995-12-31

    Coherent diffractive {rho} production by neutrinos occurs at low four-momentum transfer and high energy transfer. These interactions are generally understood to occur via the coupling of the weak charged current to the vector meson, which scatters diffractively from the target nucleus. Since coherent events are those in which the nucleus interacts as a whole, ie without breakup, and with small recoil energy, these events have a very sharp |t|-distribution. This presentation deals mostly with the Monte Carlo simulation of the coherent diffractive production of the {rho} production and in particular with the reconstruction algorithm (description and efficiency) and the |t| distribution. 4 refs., 1 fig.

  16. The Coherent Curriculum

    Institute of Scientific and Technical Information of China (English)

    Michael Thomas

    2005-01-01

    @@ What makes a coherent EFL curriculum? How can curriculum planners avoid a mismatch between policy and pragmatics to produce an effective decision-making process? In The Second Language Curriculum, Johnson describes the coherent curriculum as one in which decision outcomes from the various stages of development are mutually consistent and complementary,and learning outcomes reflect curriculum aims.The achievement of coherence is said to depend crucially in most educational contexts upon the formalisation of decision-making processes and products. This formalisation facilitates consensus among those involved and is a prerequisite for effective evaluation and subsequent renewal (1994: xiii)

  17. Coherence in Industrial Transformation

    DEFF Research Database (Denmark)

    Jørgensen, Ulrik; Lauridsen, Erik Hagelskjær

    2003-01-01

    The notion of coherence is used to illustrate the general finding, that the impact of environmental management systems and environmental policy is highly dependent of the context and interrelatedness of the systems, procedures and regimes established in society....

  18. Coherence for Modalities

    CERN Document Server

    Dosen, K

    2008-01-01

    Positive modalities in systems in the vicinity of S4 and S5 are investigated in terms of categorial proof theory. Coherence and maximality results are demonstrated, and connections with mixed distributive laws and Frobenius algebras are exhibited.

  19. Coherence in Industrial Transformation

    DEFF Research Database (Denmark)

    Jørgensen, Ulrik; Lauridsen, Erik Hagelskjær

    2003-01-01

    The notion of coherence is used to illustrate the general finding, that the impact of environmental management systems and environmental policy is highly dependent of the context and interrelatedness of the systems, procedures and regimes established in society....

  20. Genuine Quantum Coherence

    CERN Document Server

    Streltsov, Alexander

    2015-01-01

    The basis of any quantum resource theory are free states and free operations, these are states and operations which can be created or performed at no cost. In the resource theory of quantum coherence free states are states which are diagonal in a fixed reference basis. This choice is natural in many experimental scenarios where the reference basis is singled out by the unavoidable decoherence. The corresponding free operations are called incoherent, they can be implemented as a generalized measurement which does not create any coherence. However, a general quantum operation admits different experimental realizations, and a quantum operation which seems incoherent in one experimental realization might create coherence in another. Starting from this observation, we propose the framework of genuine quantum coherence. This approach is based on a simple principle: we demand that a genuinely incoherent operation preserves all incoherent states. This simple condition automatically guarantees that the operation is in...

  1. Partially coherent sources with circular coherence: comment.

    Science.gov (United States)

    Hyde, Milo W; Bose-Pillai, Santasri R

    2017-08-15

    In [Opt. Lett.42, 1512 (2017)OPLEDP0146-959210.1364/OL.42.001512], the authors present a new class of non-uniformly correlated sources with circular coherence. They also describe a basic experimental setup for synthesizing this class of sources, which uses the Van Cittert-Zernike theorem. Here, we present an alternative way to analyze these sources and a different way to generate them.

  2. Coherence-Enhanced Spaser

    CERN Document Server

    Dorfman, Konstantin E; Voronine, Dmitri V; Genevet, Patrice; Capasso, Federico; Scully, Marlan O

    2012-01-01

    We investigate surface plasmon amplification in a silver nanoshell coupled to an externally driven three-level gain medium, and show that quantum coherence significantly enhances the generation of surface plasmons. Surface plasmon amplification by stimulated emission of radiation is achieved in the absence of population inversion on the spasing transition, which reduces the pump requirements. The coherent drive allows us to control the dynamics, and holds promise for quantum control of nanoplasmonic devices.

  3. Optical Coherency Matrix Tomography

    Science.gov (United States)

    2015-10-19

    optics has been studied theoretically11, but has not been demonstrated experimentally heretofore. Even in the simplest case of two binary DoFs6 (e.g...coherency matrix G spanning these DoFs. This optical coherency matrix has not been measured in its entirety to date—even in the simplest case of two...dense coding, etc. CREOL, The College of Optics & Photonics, University of Central Florida, Orlando , Florida 32816, USA. Correspondence and requests

  4. Coherence vortices of partially coherent beams in the far field

    Institute of Scientific and Technical Information of China (English)

    Liu Pu-Sheng; Lü Bai-da

    2007-01-01

    Based on the propagation law of cross-spectral density function, studied in this paper are the coherence vortices of partially coherent, quasi-monochromatic singular beams with Gaussian envelope and Schell-model correlator in the far field, where our main attention is paid to the evolution of far-field coherence vortices into intensity vortices of fully coherent beams. The results show that, although there are usually no zeros of intensity in partially coherent beams with Gaussian envelope and Schell-model correlator, zeros of spectral degree of coherence exist. The coherence vortices of spectral degree of coherence depend on the relative coherence length, mode index and positions of pairs of points.If a point and mode index are kept fixed, the position of coherence vortices changes with the increase of the relative coherence length. For the low coherent case there is a circular phase dislocation. In the coherent limit coherence vortices become intensity vortices of fully coherent Laguerre-Gaussian beams.

  5. Interferometric visibility and coherence

    Science.gov (United States)

    Biswas, Tanmoy; García Díaz, María; Winter, Andreas

    2017-07-01

    Recently, the basic concept of quantum coherence (or superposition) has gained a lot of renewed attention, after Baumgratz et al. (Phys. Rev. Lett. 113, 140401. (doi:10.1103/PhysRevLett.113.140401)), following Åberg (http://arxiv.org/abs/quant-ph/0612146), have proposed a resource theoretic approach to quantify it. This has resulted in a large number of papers and preprints exploring various coherence monotones, and debating possible forms for the resource theory. Here, we take the view that the operational foundation of coherence in a state, be it quantum or otherwise wave mechanical, lies in the observation of interference effects. Our approach here is to consider an idealized multi-path interferometer, with a suitable detector, in such a way that the visibility of the interference pattern provides a quantitative expression of the amount of coherence in a given probe state. We present a general framework of deriving coherence measures from visibility, and demonstrate it by analysing several concrete visibility parameters, recovering some known coherence measures and obtaining some new ones.

  6. Genuine quantum coherence

    Science.gov (United States)

    de Vicente, Julio I.; Streltsov, Alexander

    2017-01-01

    Any quantum resource theory is based on free states and free operations, i.e. states and operations which can be created and performed at no cost. In the resource theory of coherence free states are diagonal in some fixed basis, and free operations are those which cannot create coherence for some particular experimental realization. Recently, some problems of this approach have been discussed, and new sets of operations have been proposed to resolve these problems. We propose here the framework of genuine quantum coherence. This approach is based on a simple principle: we demand that a genuinely incoherent operation preserves all incoherent states. This framework captures coherence under additional constrains such as energy preservation and all genuinely incoherent operations are incoherent regardless of their particular experimental realization. We also introduce the full class of operations with this property, which we call fully incoherent. We analyze in detail the mathematical structure of these classes and also study possible state transformations. We show that deterministic manipulation is severely limited, even in the asymptotic settings. In particular, this framework does not have a unique golden unit, i.e. there is no single state from which all other states can be created deterministically with the free operations. This suggests that any reasonably powerful resource theory of coherence must contain free operations which can potentially create coherence in some experimental realization.

  7. Stimulated coherent transition radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hung-chi Lihn

    1996-03-01

    Coherent radiation emitted from a relativistic electron bunch consists of wavelengths longer than or comparable to the bunch length. The intensity of this radiation out-numbers that of its incoherent counterpart, which extends to wavelengths shorter than the bunch length, by a factor equal to the number of electrons in the bunch. In typical accelerators, this factor is about 8 to 11 orders of magnitude. The spectrum of the coherent radiation is determined by the Fourier transform of the electron bunch distribution and, therefore, contains information of the bunch distribution. Coherent transition radiation emitted from subpicosecond electron bunches at the Stanford SUNSHINE facility is observed in the far-infrared regime through a room-temperature pyroelectric bolometer and characterized through the electron bunch-length study. To measure the bunch length, a new frequency-resolved subpicosecond bunch-length measuring system is developed. This system uses a far-infrared Michelson interferometer to measure the spectrum of coherent transition radiation through optical autocorrelation with resolution far better than existing time-resolved methods. Hence, the radiation spectrum and the bunch length are deduced from the autocorrelation measurement. To study the stimulation of coherent transition radiation, a special cavity named BRAICER is invented. Far-infrared light pulses of coherent transition radiation emitted from electron bunches are delayed and circulated in the cavity to coincide with subsequent incoming electron bunches. This coincidence of light pulses with electron bunches enables the light to do work on electrons, and thus stimulates more radiated energy. The possibilities of extending the bunch-length measuring system to measure the three-dimensional bunch distribution and making the BRAICER cavity a broadband, high-intensity, coherent, far-infrared light source are also discussed.

  8. SAR image effects on coherence and coherence estimation.

    Energy Technology Data Exchange (ETDEWEB)

    Bickel, Douglas Lloyd

    2014-01-01

    Radar coherence is an important concept for imaging radar systems such as synthetic aperture radar (SAR). This document quantifies some of the effects in SAR which modify the coherence. Although these effects can disrupt the coherence within a single SAR image, this report will focus on the coherence between separate images, such as for coherent change detection (CCD) processing. There have been other presentations on aspects of this material in the past. The intent of this report is to bring various issues that affect the coherence together in a single report to support radar engineers in making decisions about these matters.

  9. Dynamic coherent backscattering mirror

    Energy Technology Data Exchange (ETDEWEB)

    Zeylikovich, I.; Xu, M., E-mail: mxu@fairfield.edu [Physics Department, Fairfield University, Fairfield, CT 06824 (United States)

    2016-02-15

    The phase of multiply scattered light has recently attracted considerable interest. Coherent backscattering is a striking phenomenon of multiple scattered light in which the coherence of light survives multiple scattering in a random medium and is observable in the direction space as an enhancement of the intensity of backscattered light within a cone around the retroreflection direction. Reciprocity also leads to enhancement of backscattering light in the spatial space. The random medium behaves as a reciprocity mirror which robustly converts a diverging incident beam into a converging backscattering one focusing at a conjugate spot in space. Here we first analyze theoretically this coherent backscattering mirror (CBM) phenomenon and then demonstrate the capability of CBM compensating and correcting both static and dynamic phase distortions occurring along the optical path. CBM may offer novel approaches for high speed dynamic phase corrections in optical systems and find applications in sensing and navigation.

  10. Coherence for Monoidal Endofunctors

    CERN Document Server

    Dosen, K

    2009-01-01

    The goal of this paper is to prove coherence results with respect to relational graphs for monoidal endofunctors, i.e. endofunctors of a monoidal category that preserve the monoidal structure up to a natural transformation that need not be an isomorphism. These results are proved first in the absence of symmetry in the monoidal structure, and then with this symmetry. In the later parts of the paper the coherence results are extended to monoidal endofunctors in monoidal categories that have diagonal or codiagonal natural transformations, or where the monoidal structure is given by finite products or coproducts. Monoidal endofunctors are interesting because they stand behind monoidal monads and comonads, for which coherence will be proved in a sequel to this paper.

  11. Dynamic coherent backscattering mirror

    Science.gov (United States)

    Xu, M.

    2016-01-01

    The phase of multiply scattered light has recently attracted considerable interest. Coherent backscattering is a striking phenomenon of multiple scattered light in which the coherence of light survives multiple scattering in a random medium and is observable in the direction space as an enhancement of the intensity of backscattered light within a cone around the retroreflection direction. Reciprocity also leads to enhancement of backscattering light in the spatial space. The random medium behaves as a reciprocity mirror which robustly converts a diverging incident beam into a converging backscattering one focusing at a conjugate spot in space. Here we first analyze theoretically this coherent backscattering mirror (CBM) phenomenon and then demonstrate the capability of CBM compensating and correcting both static and dynamic phase distortions occurring along the optical path. CBM may offer novel approaches for high speed dynamic phase corrections in optical systems and find applications in sensing and navigation. PMID:26937296

  12. Coherence in Microchip Traps

    CERN Document Server

    Treutlein, P; Steinmetz, T; Hänsch, T W; Reichel, J; Treutlein, Philipp; Hommelhoff, Peter; Steinmetz, Tilo; H\\"ansch, Theodor W.; Reichel, Jakob

    2003-01-01

    We report the coherent manipulation of internal states of neutral atoms in a magnetic microchip trap. Coherence lifetimes exceeding 1 s are observed with atoms at distances of $4-130 \\mu$m from the microchip surface. The coherence lifetime in the microtrap is independent of atom-surface distance and agrees well with the results of similar measurements in macroscopic magnetic traps. Due to the absence of surface-induced decoherence, a miniaturized atomic clock with a relative stability in the $10^{-13}$ range can be realized. For applications in quantum information processing, we propose to use microwave near-fields in the proximity of chip wires to create potentials that depend on the internal state of the atoms.

  13. Hybrid vehicles

    Energy Technology Data Exchange (ETDEWEB)

    West, J.G.W. [Electrical Machines (United Kingdom)

    1997-07-01

    The reasons for adopting hybrid vehicles result mainly from the lack of adequate range from electric vehicles at an acceptable cost. Hybrids can offer significant improvements in emissions and fuel economy. Series and parallel hybrids are compared. A combination of series and parallel operation would be the ideal. This can be obtained using a planetary gearbox as a power split device allowing a small generator to transfer power to the propulsion motor giving the effect of a CVT. It allows the engine to run at semi-constant speed giving better fuel economy and reduced emissions. Hybrid car developments are described that show the wide range of possible hybrid systems. (author)

  14. Maintaining Web Cache Coherency

    Directory of Open Access Journals (Sweden)

    2000-01-01

    Full Text Available Document coherency is a challenging problem for Web caching. Once the documents are cached throughout the Internet, it is often difficult to keep them coherent with the origin document without generating a new traffic that could increase the traffic on the international backbone and overload the popular servers. Several solutions have been proposed to solve this problem, among them two categories have been widely discussed: the strong document coherency and the weak document coherency. The cost and the efficiency of the two categories are still a controversial issue, while in some studies the strong coherency is far too expensive to be used in the Web context, in other studies it could be maintained at a low cost. The accuracy of these analysis is depending very much on how the document updating process is approximated. In this study, we compare some of the coherence methods proposed for Web caching. Among other points, we study the side effects of these methods on the Internet traffic. The ultimate goal is to study the cache behavior under several conditions, which will cover some of the factors that play an important role in the Web cache performance evaluation and quantify their impact on the simulation accuracy. The results presented in this study show indeed some differences in the outcome of the simulation of a Web cache depending on the workload being used, and the probability distribution used to approximate updates on the cached documents. Each experiment shows two case studies that outline the impact of the considered parameter on the performance of the cache.

  15. Coherent light microscopy

    CERN Document Server

    Ferraro, Pietro; Zalevsky, Zeev

    2011-01-01

    This book deals with the latest achievements in the field of optical coherent microscopy. While many other books exist on microscopy and imaging, this book provides a unique resource dedicated solely to this subject. Similarly, many books describe applications of holography, interferometry and speckle to metrology but do not focus on their use for microscopy. The coherent light microscopy reference provided here does not focus on the experimental mechanics of such techniques but instead is meant to provide a users manual to illustrate the strengths and capabilities of developing techniques. Th

  16. Coherent states measurement entropy

    CERN Document Server

    Kwapien, J; Zyczkowski, K; Kwapien, Jaroslaw; Slomczynski, Wojciech; Zyczkowski, Karol

    1996-01-01

    Coherent states (CS) quantum entropy can be split into two components. The dynamical entropy is linked with the dynamical properties of a quantum system. The measurement entropy, which tends to zero in the semiclassical limit, describes the unpredictability induced by the process of a quantum approximate measurement. We study the CS--measurement entropy for spin coherent states defined on the sphere discussing different methods dealing with the time limit n \\to \\infty. In particular we propose an effective technique of computing the entropy by iterated function systems. The dependence of CS--measurement entropy on the character of the partition of the phase space is analysed.

  17. Coherent terahertz photonics.

    Science.gov (United States)

    Seeds, Alwyn J; Fice, Martyn J; Balakier, Katarzyna; Natrella, Michele; Mitrofanov, Oleg; Lamponi, Marco; Chtioui, Mourad; van Dijk, Frederic; Pepper, Michael; Aeppli, Gabriel; Davies, A Giles; Dean, Paul; Linfield, Edmund; Renaud, Cyril C

    2013-09-23

    We present a review of recent developments in THz coherent systems based on photonic local oscillators. We show that such techniques can enable the creation of highly coherent, thus highly sensitive, systems for frequencies ranging from 100 GHz to 5 THz, within an energy efficient integrated platform. We suggest that such systems could enable the THz spectrum to realize its full applications potential. To demonstrate how photonics-enabled THz systems can be realized, we review the performance of key components, show recent demonstrations of integrated platforms, and give examples of applications.

  18. Coherency matrix formulation for partially coherent imaging to evaluate the degree of coherence for image.

    Science.gov (United States)

    Yamazoe, Kenji

    2012-08-01

    This paper defines a matrix from which coherence property of imaging by partially coherent Koehler illumination is determined. The matrix termed coherency matrix in imaging system is derived by the space average of a product of a column vector and its transpose conjugate where each row of the column vector represents mutually incoherent light. The coherency matrix in imaging system has similar properties to the polarization matrix that is utilized for calculating the light intensity and degree of polarization of polarized light. The coherency matrix in imaging system enables us to calculate not only image intensity but also degree of coherence for image. Simulation results of the degree of coherence for image given by the coherency matrix in imaging system correspond to the complex degree of coherence obtained by the van Cittert-Zernike theorem.

  19. Coherence Constraints and the Last Hidden Optical Coherence

    CERN Document Server

    Qian, Xiao-Feng; Vamivakas, A Nick; Eberly, Joseph H

    2016-01-01

    We have discovered a new domain of optical coherence, and show that it is the third and last member of a previously unreported fundamental triad of coherences. These are unified by our derivation of a parallel triad of coherence constraints that take the form of complementarity relations. We have been able to enter this new coherence domain experimentally and we describe the novel tomographic approach devised for that purpose.

  20. The Coherence of Autism

    Science.gov (United States)

    Hobson, R. Peter

    2014-01-01

    There is a growing body of opinion that we should view autism as fractionable into different, largely independent sets of clinical features. The alternative view is that autism is a coherent syndrome in which principal features of the disorder stand in intimate developmental relationship with each other. Studies of congenitally blind children…

  1. Dental Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Kun-Feng Lin

    2013-07-01

    Full Text Available This review paper describes the applications of dental optical coherence tomography (OCT in oral tissue images, caries, periodontal disease and oral cancer. The background of OCT, including basic theory, system setup, light sources, spatial resolution and system limitations, is provided. The comparisons between OCT and other clinical oral diagnostic methods are also discussed.

  2. Bicartesian Coherence Revisited

    CERN Document Server

    Dosen, K

    2007-01-01

    A survey is given of results about coherence for categories with finite products and coproducts. For these results, which were published previously by the authors in several places, some formulations and proofs are here corrected, and matters are updated. The categories investigated in this paper formalize equality of proofs in classical and intuitionistic conjunctive-disjunctive logic without distribution of conjunction over disjunction.

  3. Coherence without Additivity.

    OpenAIRE

    2002-01-01

    The Dutch book argument is a coherence condition for the existence of subjective probabilities. This note gives a general framework of analysis for this argument in a nonadditive probability setting. Particular cases are given by comonotonic and affinely related Dutch books that lead to Choquet expectations and Min expectations.

  4. Coherently combining antennas

    Science.gov (United States)

    Dybdal, Robert B. (Inventor); Curry, Samuel J. (Inventor)

    2009-01-01

    An apparatus includes antenna elements configured to receive a signal including pseudo-random code, and electronics configured to use the pseudo-random code to determine time delays of signals incident upon the antenna elements and to compensate the signals to coherently combine the antenna elements.

  5. Multiphoton coherent population oscillation

    CERN Document Server

    Sharypov, A V

    2014-01-01

    We study the bichromatic driving of a two-level system which displays long-lived coherent population oscillations (CPO). We show that under certain conditions, multiphoton parametric interaction leads to the appearance of CPO resonances at the subharmonic frequencies. In addition, in the region of the CPO resonances, there is strong parametric interaction between the weak sideband components of the electromagnetic field.

  6. Optical Coherence Tomography

    DEFF Research Database (Denmark)

    Andersen, Peter E.

    2015-01-01

    Optical coherence tomography (OCT) is a noninvasive imaging technique that provides real-time two- and three-dimensional images of scattering samples with micrometer resolution. Mapping the local reflectivity, OCT visualizes the morphology of the sample, in real time or at video rate. In addition...

  7. Hybrid Long-Distance Entanglement Distribution Protocol

    DEFF Research Database (Denmark)

    Brask, J.B.; Rigas, I.; Polzik, E.S.;

    2010-01-01

    We propose a hybrid (continuous-discrete variable) quantum repeater protocol for long-distance entanglement distribution. Starting from states created by single-photon detection, we show how entangled coherent state superpositions can be generated by means of homodyne detection. We show that near...

  8. Coherent states in quantum mechanics

    CERN Document Server

    Rodrigues, R D L; Fernandes, D

    2001-01-01

    We present a review work on the coherent states is non-relativistic quantum mechanics analysing the quantum oscillators in the coherent states. The coherent states obtained via a displacement operator that act on the wave function of ground state of the oscillator and the connection with Quantum Optics which were implemented by Glauber have also been considered. A possible generalization to the construction of new coherent states it is point out.

  9. Optical Coherence and Quantum Optics

    CERN Document Server

    Mandel, Leonard

    1995-01-01

    This book presents a systematic account of optical coherence theory within the framework of classical optics, as applied to such topics as radiation from sources of different states of coherence, foundations of radiometry, effects of source coherence on the spectra of radiated fields, coherence theory of laser modes, and scattering of partially coherent light by random media. The book starts with a full mathematical introduction to the subject area and each chapter concludes with a set of exercises. The authors are renowned scientists and have made substantial contributions to many of the topi

  10. Quantum coherence: Reciprocity and distribution

    Science.gov (United States)

    Kumar, Asutosh

    2017-03-01

    Quantum coherence is the outcome of the superposition principle. Recently, it has been theorized as a quantum resource, and is the premise of quantum correlations in multipartite systems. It is therefore interesting to study the coherence content and its distribution in a multipartite quantum system. In this work, we show analytically as well as numerically the reciprocity between coherence and mixedness of a quantum state. We find that this trade-off is a general feature in the sense that it is true for large spectra of measures of coherence and of mixedness. We also study the distribution of coherence in multipartite systems by looking at monogamy-type relation-which we refer to as additivity relation-between coherences of different parts of the system. We show that for the Dicke states, while the normalized measures of coherence violate the additivity relation, the unnormalized ones satisfy the same.

  11. Spectral coherence in windturbine wakes

    Energy Technology Data Exchange (ETDEWEB)

    Hojstrup, J. [Riso National Lab., Roskilde (Denmark)

    1996-12-31

    This paper describes an experiment at a Danish wind farm to investigate the lateral and vertical coherences in the nonequilibrium turbulence of a wind turbine wake. Two meteorological masts were instrumented for measuring profiles of mean speed, turbulence, and temperature. Results are provided graphically for turbulence intensities, velocity spectra, lateral coherence, and vertical coherence. The turbulence was somewhat influenced by the wake, or possibly from aggregated wakes further upstream, even at 14.5 diameters. Lateral coherence (separation 5m) seemed to be unaffected by the wake at 7.5 diameters, but the flow was less coherent in the near wake. The wake appeared to have little influence on vertical coherence (separation 13m). Simple, conventional models for coherence appeared to be adequate descriptions for wake turbulence except for the near wake situation. 3 refs., 7 figs., 1 tab.

  12. Coherent branching feature bisimulation

    Directory of Open Access Journals (Sweden)

    Tessa Belder

    2015-04-01

    Full Text Available Progress in the behavioral analysis of software product lines at the family level benefits from further development of the underlying semantical theory. Here, we propose a behavioral equivalence for feature transition systems (FTS generalizing branching bisimulation for labeled transition systems (LTS. We prove that branching feature bisimulation for an FTS of a family of products coincides with branching bisimulation for the LTS projection of each the individual products. For a restricted notion of coherent branching feature bisimulation we furthermore present a minimization algorithm and show its correctness. Although the minimization problem for coherent branching feature bisimulation is shown to be intractable, application of the algorithm in the setting of a small case study results in a significant speed-up of model checking of behavioral properties.

  13. Coherent Transient Systems Evaluation

    Science.gov (United States)

    1993-06-17

    manuscript is submitted for publication with the understanding that the United States Government is authorized to reproduce and distribute reprints...for governmental purposes. 1.0 Introduction The continuous optical correlator presented here is based on the phenomena of coherent transients, also...Gating the Continuous Processor Programming the continuous processor is accomplished by illuminati , n, the material with ,.’ modulated light pulses: a

  14. Coherent laser vision system

    Energy Technology Data Exchange (ETDEWEB)

    Sebastion, R.L. [Coleman Research Corp., Springfield, VA (United States)

    1995-10-01

    The Coherent Laser Vision System (CLVS) is being developed to provide precision real-time 3D world views to support site characterization and robotic operations and during facilities Decontamination and Decommissioning. Autonomous or semiautonomous robotic operations requires an accurate, up-to-date 3D world view. Existing technologies for real-time 3D imaging, such as AM laser radar, have limited accuracy at significant ranges and have variability in range estimates caused by lighting or surface shading. Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no-moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic to coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system.

  15. Photoacoustics with coherent light

    Directory of Open Access Journals (Sweden)

    Emmanuel Bossy

    2016-03-01

    Full Text Available Since its introduction in the mid-nineties, photoacoustic imaging of biological tissue has been one of the fastest growing biomedical imaging modality, and its basic principles are now considered as well established. In particular, light propagation in photoacoustic imaging is generally considered from the perspective of transport theory. However, recent breakthroughs in optics have shown that coherent light propagating through optically scattering medium could be manipulated towards novel imaging approaches. In this article, we first provide an introduction to the relevant concepts in the field, and then review the recent works showing that it is possible to exploit the coherence of light in conjunction with photoacoustics. We illustrate how the photoacoustic effect can be used as a powerful feedback mechanism for optical wavefront shaping in complex media, and conversely show how the coherence of light can be exploited to enhance photoacoustic imaging, for instance in terms of spatial resolution or for designing minimally invasive endoscopic devices. Finally, we discuss the current challenges and perspectives down the road towards practical applications in the field of photoacoustic imaging.

  16. Coherent electron cooling

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko,V.

    2009-05-04

    Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation is still too feeble, while the efficiency of two other cooling methods, stochastic and electron, falls rapidly either at high bunch intensities (i.e. stochastic of protons) or at high energies (e-cooling). In this talk a specific scheme of a unique cooling technique, Coherent Electron Cooling, will be discussed. The idea of coherent electron cooling using electron beam instabilities was suggested by Derbenev in the early 1980s, but the scheme presented in this talk, with cooling times under an hour for 7 TeV protons in the LHC, would be possible only with present-day accelerator technology. This talk will discuss the principles and the main limitations of the Coherent Electron Cooling process. The talk will describe the main system components, based on a high-gain free electron laser driven by an energy recovery linac, and will present some numerical examples for ions and protons in RHIC and the LHC and for electron-hadron options for these colliders. BNL plans a demonstration of the idea in the near future.

  17. Ionization penalty in nonlinear Raman neuroimaging.

    Science.gov (United States)

    Voronin, Aleksandr A; Fedotov, Ilya V; Doronina-Amitonova, Lyubov V; Ivashkina, Olga I; Zots, Marina A; Fedotov, Andrei B; Anokhin, Konstantin V; Zheltikov, Aleksei M

    2011-02-15

    Light-assisted ionization accompanying coherent anti-Stokes Raman scattering (CARS) of ultrashort laser pulses in brain tissue is shown to manifest itself in a detectable blueshift of the anti-Stokes signal. This blueshift can serve as an indicator of ionization processes in CARS-based neuroimaging.

  18. Coherent coupling of molecular resonators with a micro-cavity mode

    CERN Document Server

    Shalabney, Atef; Hutchison, James A; Pupillo, Guido; Genet, Cyriaque; Ebbesen, Thomas W

    2014-01-01

    Strong coupling is at the heart of optomechanics where it enables coherent quantum state transfer between light and micromechanical oscillators. Strongly coupled molecule-cavity systems have also revealed unique properties enabling even the control of chemical rates through the optical hybridization of the electronic states. Here we combine these notions to show that molecular vibrational modes of the electronic ground state can be coherently coupled with a micro-cavity mode at room temperature, given the low vibrational thermal occupation factors n_{\

  19. Microwave-Driven Coherent Operation of a Semiconductor Quantum Dot Charge Qubit (Author’s Manuscript)

    Science.gov (United States)

    2015-02-16

    Microwave-driven coherent operation of a semiconductor quantum dot charge qubit Dohun Kim,1 D. R. Ward,1 C. B. Simmons,1 John King Gamble,2 Robin...Fig.4a. Coherent microwave ac-gating of a semiconductor quantum dot charge qubit offers fast ( >GHz) manip- ulation rates for all elementary rotation...2014). [12] Kim, D. et al. Quantum control and process tomography of a semiconductor quantum dot hybrid qubit. Nature 511, 70–74 (2014). [13] Vion, D

  20. Holographic microscopy in low coherence

    Science.gov (United States)

    Chmelík, Radim; Petráček, Jiří; Slabá, Michala; Kollárová, Věra; Slabý, Tomáš; Čolláková, Jana; Komrska, Jiří; Dostál, Zbyněk.; Veselý, Pavel

    2016-03-01

    Low coherence of the illumination substantially improves the quality of holographic and quantitative phase imaging (QPI) by elimination of the coherence noise and various artefacts and by improving the lateral resolution compared to the coherent holographic microscopy. Attributes of coherence-controlled holographic microscope (CCHM) designed and built as an off-axis holographic system allowing QPI within the range from complete coherent to incoherent illumination confirmed these expected advantages. Low coherence illumination also furnishes the coherence gating which constraints imaging of some spatial frequencies of an object axially thus forming an optical section in the wide sense. In this way the depth discrimination capability of the microscope is introduced at the price of restricting the axial interval of possible numerical refocusing. We describe theoretically these effects for the whole range of illumination coherence. We also show that the axial refocusing constraints can be overcome using advanced mode of imaging based on mutual lateral shift of reference and object image fields in CCHM. Lowering the spatial coherence of illumination means increasing its numerical aperture. We study how this change of the illumination geometry influences 3D objects QPI and especially the interpretation of live cells QPI in terms of the dry mass density measurement. In this way a strong dependence of the imaging process on the light coherence is demonstrated. The theoretical calculations and numerical simulations are supported by experimental data including a chance of time-lapse watching of live cells even in optically turbid milieu.

  1. Topological Properties of Spatial Coherence Function

    Institute of Scientific and Technical Information of China (English)

    REN Ji-Rong; ZHU Tao; DUAN Yi-Shi

    2008-01-01

    The topological properties of the spatial coherence function are investigated rigorously.The phase singular structures(coherence vortices)of coherence function can be naturally deduced from the topological current,which is an abstract mathematical object studied previously.We find that coherence vortices are characterized by the Hopf index and Brouwer degree in topology.The coherence flux quantization and the linking of the closed coherence vortices are also studied from the topological properties of the spatial coherence function.

  2. Hybrid Metaheuristics

    CERN Document Server

    2013-01-01

    The main goal of this book is to provide a state of the art of hybrid metaheuristics. The book provides a complete background that enables readers to design and implement hybrid metaheuristics to solve complex optimization problems (continuous/discrete, mono-objective/multi-objective, optimization under uncertainty) in a diverse range of application domains. Readers learn to solve large scale problems quickly and efficiently combining metaheuristics with complementary metaheuristics, mathematical programming, constraint programming and machine learning. Numerous real-world examples of problems and solutions demonstrate how hybrid metaheuristics are applied in such fields as networks, logistics and transportation, bio-medical, engineering design, scheduling.

  3. Assisted distillation of quantum coherence

    CERN Document Server

    Chitambar, E; Rana, S; Bera, M N; Adesso, G; Lewenstein, M

    2015-01-01

    We introduce and study the task of assisted coherence distillation. This task arises naturally in bipartite systems where both parties work together to generate the maximal possible coherence on one of the subsystems. Only incoherent operations are allowed on the target system while general local quantum operations are permitted on the other, an operational paradigm that we call local quantum-incoherent operations and classical communication (LQICC). We show that the asymptotic rate of assisted coherence distillation for pure states is equal to the coherence of assistance, a direct analog of the entanglement of assistance, whose properties we characterize. Our findings imply a novel interpretation of the von Neumann entropy: it quantifies the maximum amount of extra quantum coherence a system can gain when receiving assistance from a collaborative party. Our results are generalized to coherence localization in a multipartite setting and possible applications are discussed.

  4. Volitional Control of Neuromagnetic Coherence

    Directory of Open Access Journals (Sweden)

    Matthew D Sacchet

    2012-12-01

    Full Text Available Coherence of neural activity between circumscribed brain regions has been implicated as an indicator of intracerebral communication in various cognitive processes. While neural activity can be volitionally controlled with neurofeedback, the volitional control of coherence has not yet been explored. Learned volitional control of coherence could elucidate mechanisms of associations between cortical areas and its cognitive correlates and may have clinical implications. Neural coherence may also provide a signal for brain-computer interfaces (BCI. In the present study we used the Weighted Overlapping Segment Averaging (WOSA method to assess coherence between bilateral magnetoencephalograph (MEG sensors during voluntary digit movement as a basis for BCI control. Participants controlled an onscreen cursor, with a success rate of 124 of 180 (68.9%, sign-test p < 0.001 and 84 out of 100 (84%, sign-test p < 0.001. The present findings suggest that neural coherence may be volitionally controlled and may have specific behavioral correlates.

  5. Quantum Coherence as a Resource

    CERN Document Server

    Streltsov, Alexander; Plenio, Martin B

    2016-01-01

    The coherent superposition of states, in combination with energy quantization, represents one of the most fundamental features that mark the departure of quantum mechanics from the classical realm. Quantum coherence in many-body systems embodies the essence of entanglement and is an essential ingredient for a plethora of physical phenomena in quantum optics, quantum information, solid state physics, and nanoscale thermodynamics. In recent years, research on the presence and functional role of quantum coherence in biological systems has also attracted a considerable interest. Despite the fundamental importance of quantum coherence, the development of a rigorous theory of quantum coherence as a physical resource has only been initiated recently. In this Colloquium we discuss and review the development of this rapidly growing research field that encompasses the characterization, quantification, manipulation, dynamical evolution, and operational application of quantum coherence.

  6. Coherent optics in students' laboratories

    Science.gov (United States)

    Senderáková, Dagmar; Mesaros, Vladimir; Drzik, Milan

    2014-12-01

    Lasers provide us with unique kind of light - coherent light. Besides being the keystone of historical interferometric measuring methods, coherent waves, now accessible in a very easy way, become a base of new optical measuring and information processing methods. Moreover, holographic recording seems today to have become a common term, even among common, not especially optically educated people. The presentation deals with our attempt to take our students' interest in the coherence of light and getting them familiar with the phenomenon, indeed.

  7. Review of Entangled Coherent States

    CERN Document Server

    Sanders, Barry C

    2011-01-01

    We review entangled coherent state research since its first implicit use in 1967 to the present. Entangled coherent states are important to quantum superselection principles, quantum information processing, quantum optics, and mathematical physics. Despite their inherent fragility they have produced in a conditional propagating-wave quantum optics realization. Fundamentally the states are intriguing because they are entanglements of the coherent states, which are in a sense the most classical of all states of a dynamical system.

  8. Coherent dynamics in semiconductors

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher

    1998-01-01

    Ultrafast nonlinear optical spectroscopy is used to study the coherent dynamics of optically excited electron-hole pairs in semiconductors. Coulomb interaction implies that the optical inter-band transitions are dominated, at least at low temperatures, by excitonic effects. They are further...... and molecular systems are found and studied in the exciton-biexciton system of semiconductors. At densities where strong exciton interactions, or many-body effects, become dominant, the semiconductor Bloch equations present a more rigorous treatment of the phenomena Ultrafast degenerate four-wave mixing is used...

  9. Diffraction coherence in optics

    CERN Document Server

    Françon, M; Green, L L

    2013-01-01

    Diffraction: Coherence in Optics presents a detailed account of the course on Fraunhofer diffraction phenomena, studied at the Faculty of Science in Paris. The publication first elaborates on Huygens' principle and diffraction phenomena for a monochromatic point source and diffraction by an aperture of simple form. Discussions focus on diffraction at infinity and at a finite distance, simplified expressions for the field, calculation of the path difference, diffraction by a rectangular aperture, narrow slit, and circular aperture, and distribution of luminous flux in the airy spot. The book th

  10. Optical coherence refractometry.

    Science.gov (United States)

    Tomlins, Peter H; Woolliams, Peter; Hart, Christian; Beaumont, Andrew; Tedaldi, Matthew

    2008-10-01

    We introduce a novel approach to refractometry using a low coherence interferometer at multiple angles of incidence. We show that for plane parallel samples it is possible to measure their phase refractive index rather than the group index that is usually measured by interferometric methods. This is a significant development because it enables bulk refractive index measurement of scattering and soft samples, not relying on surface measurements that can be prone to error. Our technique is also noncontact and compatible with in situ refractive index measurements. Here, we demonstrate this new technique on a pure silica test piece and a highly scattering resin slab, comparing the results with standard critical angle refractometry.

  11. Objective Eulerian Coherent Structures

    CERN Document Server

    Serra, M

    2015-01-01

    We define objective Eulerian Coherent Structures (OECSs) in two-dimensional, non-autonomous dynamical systems as instantaneously most influential material curves. Specifically, OECSs are stationary curves of the averaged instantaneous material stretching-rate or material shearing-rate functionals. From these objective (frame-invariant) variational principles, we obtain explicit differential equations for hyperbolic, elliptic and parabolic OECSs. As illustration, we compute OECSs in an unsteady ocean velocity data set. In comparison to structures suggested by other common Eulerian diagnostic tools, we find OECSs to be the correct short-term cores of observed trajectory deformation patterns.

  12. Coherent laser beam combining

    CERN Document Server

    Brignon, Arnaud

    2013-01-01

    Recently, the improvement of diode pumping in solid state lasers and the development of double clad fiber lasers have allowed to maintain excellent laser beam quality with single mode fibers. However, the fiber output power if often limited below a power damage threshold. Coherent laser beam combining (CLBC) brings a solution to these limitations by identifying the most efficient architectures and allowing for excellent spectral and spatial quality. This knowledge will become critical for the design of the next generation high-power lasers and is of major interest to many industrial, environme

  13. The Puzzle of Coherence

    DEFF Research Database (Denmark)

    Andersen, Anne Bendix; Frederiksen, Kirsten; Beedholm, Kirsten;

    2016-01-01

    in general practice, outpatient clinics, home care and physiotherapy. Furthermore, field observations are conducted in general practice, home care and rehabilitation settings. Perspectives Knowledge about the practice of cross-sectorial collaboration is crucial to the future planning of collaborating...... initiatives in health care. The present study will generate new, valuable insight into the areas of cross-sectorial health care collaboration. Our findings may facilitate change in current practice and improve the quality and coherence in patient pathways of EPCD. The findings of this study will be useful...

  14. Coherent signal processing in optical coherence tomography

    Science.gov (United States)

    Kulkarni, Manish Dinkarrao

    1999-09-01

    Optical coherence tomography (OCT) is a novel method for non-invasive sub-surface imaging of biological tissue micro-structures. OCT achieves high spatial resolution ( ~ 15 m m in three dimensions) using a fiber-optically integrated system which is suitable for application in minimally invasive diagnostics, including endoscopy. OCT uses an optical heterodyne detection technique based on white light interferometry. Therefore extremely faint reflections ( ~ 10 fW) are routinely detected with high spatial localization. The goal of this thesis is twofold. The first is to present a theoretical model for describing image formation in OCT, and attempt to enhance the current level of understanding of this new modality. The second objective is to present signal processing methods for improving OCT image quality. We present deconvolution algorithms to obtain improved longitudinal resolution in OCT. This technique may be implemented without increasing system complexity as compared to current clinical OCT systems. Since the spectrum of the light backscattered from bio-scatterers is closely associated with ultrastructural variations in tissue, we propose a new technique for measuring spectra as a function of depth. This advance may assist OCT in differentiating various tissue types and detecting abnormalities within a tissue. In addition to depth resolved spectroscopy, Doppler processing of OCT signals can also improve OCT image contrast. We present a new technique, termed color Doppler OCT (CDOCT). It is an innovative extension of OCT for performing spatially localized optical Doppler velocimetry. Micron-resolution imaging of blood flow in sub-surface vessels in living tissue using CDOCT is demonstrated. The fundamental issues regarding the trade- off between the velocity estimation precision and image acquisition rate are presented. We also present novel algorithms for high accuracy velocity estimation. In many blood vessels velocities tend to be on the order of a few cm

  15. Effects of Herzberg--Teller vibronic coupling on coherent excitation energy transfer

    CERN Document Server

    Zhang, Hou-Dao; Xu, Rui-Xue; Yan, YiJing

    2016-01-01

    In this work, we study the effects of non-Condon vibronic coupling on the quantum coherence of excitation energy transfer, via the exact dissipaton-equation-of-motion (DEOM) evaluations on excitonic model systems. Field-triggered excitation energy transfer dynamics and two dimensional coherent spectroscopy are simulated for both Condon and non-Condon vibronic couplings. Our results clearly demonstrate that the non-Condon vibronic coupling intensifies the dynamical electronic-vibrational energy transfer and enhances the total system-and-bath quantum coherence. Moreover, the hybrid bath dynamics for non-Condon effects enriches the theoretical calculation, and further sheds light on the interpretation of the experimental nonlinear spectroscopy.

  16. Perspective: Quantum or classical coherence?

    Science.gov (United States)

    Miller, William H

    2012-06-07

    Some coherence effects in chemical dynamics are described correctly by classical mechanics, while others only appear in a quantum treatment--and when these are observed experimentally it is not always immediately obvious whether their origin is classical or quantum. Semiclassical theory provides a systematic way of adding quantum coherence to classical molecular dynamics and thus provides a useful way to distinguish between classical and quantum coherence. Several examples are discussed which illustrate both cases. Particularly interesting is the situation with electronically non-adiabatic processes, where sometimes whether the coherence effects are classical or quantum depends on what specific aspects of the process are observed.

  17. Coherent states on the circle

    CERN Document Server

    Chadzitaskos, G; Tolar, J

    2011-01-01

    We present a possible construction of coherent states on the unit circle as configuration space. In our approach the phase space is the product Z x S^1. Because of the duality of canonical coordinates and momenta, i.e. the angular variable and the integers, this formulation can also be interpreted as coherent states over an infinite periodic chain. For the construction we use the analogy with our quantization over a finite periodic chain where the phase space was Z_M x Z_M. Properties of the coherent states constructed in this way are studied and the coherent states are shown to satisfy the resolution of unity.

  18. Converting Coherence to Quantum Correlations.

    Science.gov (United States)

    Ma, Jiajun; Yadin, Benjamin; Girolami, Davide; Vedral, Vlatko; Gu, Mile

    2016-04-22

    Recent results in quantum information theory characterize quantum coherence in the context of resource theories. Here, we study the relation between quantum coherence and quantum discord, a kind of quantum correlation which appears even in nonentangled states. We prove that the creation of quantum discord with multipartite incoherent operations is bounded by the amount of quantum coherence consumed in its subsystems during the process. We show how the interplay between quantum coherence consumption and creation of quantum discord works in the preparation of multipartite quantum correlated states and in the model of deterministic quantum computation with one qubit.

  19. Hybrid intermediaries

    OpenAIRE

    Cetorelli, Nicola

    2014-01-01

    I introduce the concept of hybrid intermediaries: financial conglomerates that control a multiplicity of entity types active in the "assembly line" process of modern financial intermediation, a system that has become known as shadow banking. The complex bank holding companies of today are the best example of hybrid intermediaries, but I argue that financial firms from the "nonbank" space can just as easily evolve into conglomerates with similar organizational structure, thus acquiring the cap...

  20. Hybrid composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2009-04-01

    Full Text Available effect was observed for the elongation at break of the hybrid composites. The impact strength of the hybrid composites increased with the addition of glass fibres. The tensile and impact properties of thermoplastic natural rubber reinforced short... panels made from conventional structural materials. Figure 3 illustrates the performance of cellular biocomposite panels against conventional systems used for building and residential construction, namely a pre- cast pre-stressed hollow core concrete...

  1. Fermionic coherent states

    Science.gov (United States)

    Combescure, Monique; Robert, Didier

    2012-06-01

    The aim of this paper is to give a self-contained and unified presentation of a fermionic coherent state theory with the necessary mathematical details, discussing their definition, properties and some applications. After defining Grassmann algebras, it is possible to get a classical analog for the fermionic degrees of freedom in a quantum system. Following the basic work of Berezin (1966 The Method of Second Quantization (New York: Academic); 1987 Introduction to Superanalysis (Dordrecht: Reidel Publishing Company)), we show that we can compute with Grassmann numbers as we do with complex numbers: derivation, integration, Fourier transform. After that we show that we have quantization formulas for fermionic observables. In particular, there exists a Moyal product formula. As an application, we consider explicit computations for propagators with quadratic Hamiltonians in annihilation and creation operators. We prove a Mehler formula for the propagator and Mehlig-Wilkinson-type formulas for the covariant and contravariant symbols of ‘metaplectic’ transformations for fermionic states. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Coherent states: mathematical and physical aspects’.

  2. Coherence for weak units

    CERN Document Server

    Joyal, André

    2009-01-01

    We define weak units in a semi-monoidal 2-category $\\CC$ as cancellable pseudo-idempotents: they are pairs $(I,\\alpha)$ where $I$ is an object such that tensoring with $I$ from either side constitutes a biequivalence of $\\CC$, and $\\alpha: I \\tensor I \\to I$ is an equivalence in $\\CC$. We show that this notion of weak unit has coherence built in: Theorem A: $\\alpha$ has a canonical associator 2-cell, which automatically satisfies the pentagon equation. Theorem B: every morphism of weak units is automatically compatible with those associators. Theorem C: the 2-category of weak units is contractible if non-empty. Finally we show (Theorem E) that the notion of weak unit is equivalent to the notion obtained from the definition of tricategory: $\\alpha$ alone induces the whole family of left and right maps (indexed by the objects), as well as the whole family of Kelly 2-cells (one for each pair of objects), satisfying the relevant coherence axioms.

  3. Laser Cooling Using Anti-Stokes Fluorescencein Yb3+-Doped Fluorozirconate Glasses

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The fluorozirconate glasses ZBLANP( ZrF4-BaF2-LaF3-AlF3-NaF-PbF2) doped with different Yb3+ concentration were prepared. The Raman spectra and absorption spectra are measured to substantiate the existence of phonon-assisted emission. After analyzing the normalized absorption spectra of samples with different Yb3+-doped concentration, we calculated the maximum cooling effect in the 3 wt% Yb3+-doped sample pumped at 1 012.5 nm. The corresponding cooling capability is about -4.09 ℃/W and the cooling efficiency reaches 1.76%.

  4. Stokes and Anti Stokes Luminescence in LiTaO3:Ho

    Science.gov (United States)

    2001-01-01

    fluoride glass ZBLAN : Ho 2 has been achieved. Very recently upconversion phenomena in YAIO3:Ho have been studied 3 . In this paper we report on...attention recently because it offers a potential of a visible laser emission. Numerous works deal with crystals and glasses doped with thulium or erbium...green (lambda -549 nm), holmium-doped fluorozirconate glass fiber laser", J Quantum Electron., 32, pp. 638-645, 1996. 3. M. Malinowski, R1

  5. Coherent Structures and Reconnection in Collisionless Turbulence

    Science.gov (United States)

    Roytershteyn, Vadim; Karimabadi, Homa

    2014-10-01

    The sub-proton range of collisionless turbulence has attracted considerable attention in the last decades due to its role in the dissipation of cascading energy and increased availability of high-quality measurements capable of constraining the relevant models. Coherent structures, such as current sheets, have long been considered important sites for the dissipation of energy. However, a self-consistent treatment of their formation and of the relevant collisionless dissipation mechanisms has only become possible recently. Here we discuss several examples from recent kinetic simulations of turbulence focusing on the role of current sheets and magnetic reconnection. In the 3D fully kinetic simulations with initial conditions relevant to solar wind turbulence, current sheets form over a large range of scales and are shown to be sites of increased energy transfer between fluctuating fields and particles. Moreover, depending on the initial conditions and the type of driving, other types of coherent structures are possible, such as magnetic holes. 2D and 3D global hybrid simulations of the interaction between solar wind and planetary magnetospheres demonstrate inherent connection between collisionless shocks, turbulence, and magnetic reconnection. Specifically, the interaction of foreshock turbulence driven by reflected ions with the shock itself leads to a variety of fascinating phenomena in the magnetosheath, seeding both small-scale turbulence and large-scale global perturbations.

  6. Robustness of a coherence vortex.

    Science.gov (United States)

    Alves, Cleberson R; Jesus-Silva, Alcenisio J; Fonseca, Eduardo J S

    2016-09-20

    We study, experimentally and theoretically, the behavior of a coherence vortex after its transmission through obstacles. Notably, we find that such a vortex survives and preserves its effective topological charge. Despite suffering changes on the modulus of the coherence function, these changes disappear during propagation.

  7. Dynamics of generalized coherent states

    CERN Document Server

    De Martino, S; Illuminati, F; De Martino, S; De Siena, S; Illuminati, F

    1995-01-01

    We show that generalized coherent states follow Schr\\"{o}dinger dynamics in time-dependent potentials. The normalized wave-packets follow a classical evolution without spreading; in turn, the Schr\\"{o}dinger potential depends on the state through the classical trajectory. This feedback mechanism with continuous dynamical re-adjustement allows the packets to remain coherent indefinetely.

  8. COHERENT LIGHT-RECORDING TECHNIQUES.

    Science.gov (United States)

    On the basis of diffraction theory, quantum-mechanics and information theory, it is shown that the principle of coherent light recording is the...mechanical, magnetic or electric approaches. Photographic coherent light recording tests were made by the dynamic sweep tests on 16 mm Recordak Micro-File

  9. COHERENT-LIGHT RECORDING TECHNIQUES.

    Science.gov (United States)

    The purpose of this report is to summarize, define and demonstrate techniques necessary for the application of coherent light to the problems of...Investigations into such areas as the coherent light source itself, modulation, deflection or scanning techniques, readout techniques and the evaluation of recording media are reported.

  10. Quantum coherence of steered states

    Science.gov (United States)

    Hu, Xueyuan; Milne, Antony; Zhang, Boyang; Fan, Heng

    2016-01-01

    Lying at the heart of quantum mechanics, coherence has recently been studied as a key resource in quantum information theory. Quantum steering, a fundamental notion originally considered by Schödinger, has also recently received much attention. When Alice and Bob share a correlated quantum system, Alice can perform a local measurement to ‘steer’ Bob’s reduced state. We introduce the maximal steered coherence as a measure describing the extent to which steering can remotely create coherence; more precisely, we find the maximal coherence of Bob’s steered state in the eigenbasis of his original reduced state, where maximization is performed over all positive-operator valued measurements for Alice. We prove that maximal steered coherence vanishes for quantum-classical states whilst reaching a maximum for pure entangled states with full Schmidt rank. Although invariant under local unitary operations, maximal steered coherence may be increased when Bob performs a channel. For a two-qubit state we find that Bob’s channel can increase maximal steered coherence if and only if it is neither unital nor semi-classical, which coincides with the condition for increasing discord. Our results show that the power of steering for coherence generation, though related to discord, is distinct from existing measures of quantum correlation.

  11. Coherence and correspondence in medicine

    Directory of Open Access Journals (Sweden)

    Thomas G. Tape

    2009-03-01

    Full Text Available Many controversies in medical science can be framed as tension between a coherence approach (which seeks logic and explanation and a correspondence approach (which emphasizes empirical correctness. In many instances, a coherence-based theory leads to an understanding of disease that is not supported by empirical evidence. Physicians and patients alike tend to favor the coherence approach even in the face of strong, contradictory correspondence evidence. Examples include the management of atrial fibrillation, treatment of acute bronchitis, and the use of Vitamin E to prevent heart disease. Despite the frequent occurrence of controversy stemming from coherence-correspondence conflicts, medical professionals are generally unaware of these terms and the philosophical traditions that underlie them. Learning about the coherence-correspondence distinction and using the best of both approaches could not only help reconcile controversy but also lead to striking advances in medical science.

  12. The Puzzle of Coherence

    DEFF Research Database (Denmark)

    Andersen, Anne Bendix; Frederiksen, Kirsten; Beedholm, Kirsten

    2016-01-01

    Background During the past decade, politicians and healthcare providers have strived to create a coherent healthcare system across primary and secondary healthcare sectors in Denmark. Nevertheless, elderly patients with chronic diseases (EPCD) continue to report experiences of poor-quality care...... to an acute care ward to discharge and later in meetings with healthcare providers in general practice, outpatient clinics, home care and physiotherapy. Furthermore, field observations were conducted in general practice, home care and rehabilitation settings. Research design An explorative design based...... on an interactionistic approach was used. As a consequence, the focus of data collection is the production of meaning happening between human beings in social interaction in the field of cross-sectorial collaboration. Research questions The research questions reflect the interactionistic approach as they concentrate...

  13. Optical coherence in astrophysics

    CERN Document Server

    Moret-Bailly, Jacques

    2013-01-01

    Many physicists and most astrophysicists assume that the photon is a small particle which, in a very low pressure gas can only interact with a single molecule. Thus, the interaction of light with this gas is incoherent. W. E.Lamb Jr, W. P. Schleich, M. O. Scully and C. H. Townes (Reviews of Modern Physics 71, S263, 1999) have criticized this view: In accordance with quantum electrodynamics the photon is a pseudo-particle resulting from the quantization of a deterministic exchange of energy between identical molecules and a normal mode of electromagnetic field. Following Lamb et al., we study models in which some variables have an unusual value for a spectroscopist: extremely low pressure hydrogen, but huge light paths, extremely hot sources. However, the magnitudes of the spectral radiances and column densities can be similar in astrophysics and in a laboratory using lasers. Thus, several coherent effects must be taken into account: superradiance, multiphoton interactions, impulsive stimulated Raman scatterin...

  14. Coherent Scatter Imaging Measurements

    Science.gov (United States)

    Ur Rehman, Mahboob

    In conventional radiography, anatomical information of the patients can be obtained, distinguishing different tissue types, e.g. bone and soft tissue. However, it is difficult to obtain appreciable contrast between two different types of soft tissues. Instead, coherent x-ray scattering can be utilized to obtain images which can differentiate between normal and cancerous cells of breast. An x-ray system using a conventional source and simple slot apertures was tested. Materials with scatter signatures that mimic breast cancer were buried in layers of fat of increasing thickness and imaged. The result showed that the contrast and signal to noise ratio (SNR) remained high even with added fat layers and short scan times.

  15. Coherent imaging without phases

    CERN Document Server

    Moscoso, Miguel; Papanicolaou, George

    2015-01-01

    In this paper we consider narrow band, active array imaging of weak localized scatterers when only the intensities are recorded at an array with N transducers. We consider that the medium is homogeneous and, hence, wave propagation is fully coherent. This work is an extension of our previous paper, where we showed that using linear combinations of intensity-only measurements imaging of localized scatterers can be carried out efficiently using MUSIC or sparsity promoting optimization. Here we show the same strategy can be accomplished with only 3N-2 illuminations, therefore reducing enormously the data acquisition process. Furthermore, we show that in the paraxial regime one can form the images by using six illuminations only. In particular, this paraxial regime includes Fresnel and Fraunhofer diffraction. The key point of this work is that if one controls the illuminations, imaging with intensity-only can be easily reduced to a imaging with phases and, therefore, one can apply standard imaging techniques. Det...

  16. Quantum information and coherence

    CERN Document Server

    Öhberg, Patrik

    2014-01-01

    This book offers an introduction to ten key topics in quantum information science and quantum coherent phenomena, aimed at graduate-student level. The chapters cover some of the most recent developments in this dynamic research field where theoretical and experimental physics, combined with computer science, provide a fascinating arena for groundbreaking new concepts in information processing. The book addresses both the theoretical and experimental aspects of the subject, and clearly demonstrates how progress in experimental techniques has stimulated a great deal of theoretical effort and vice versa. Experiments are shifting from simply preparing and measuring quantum states to controlling and manipulating them, and the book outlines how the first real applications, notably quantum key distribution for secure communication, are starting to emerge. The chapters cover quantum retrodiction, ultracold quantum gases in optical lattices, optomechanics, quantum algorithms, quantum key distribution, quantum cont...

  17. Optical Coherence Tomography

    DEFF Research Database (Denmark)

    Mogensen, Mette; Themstrup, Lotte; Banzhaf, Christina

    2014-01-01

    as the optical analogue to ultrasound. The inherent safety of the technology allows for in vivo use of OCT in patients. The main strength of OCT is the depth resolution. In dermatology, most OCT research has turned on non-melanoma skin cancer (NMSC) and non-invasive monitoring of morphological changes......Optical coherence tomography (OCT) has developed rapidly since its first realisation in medicine and is currently an emerging technology in the diagnosis of skin disease. OCT is an interferometric technique that detects reflected and backscattered light from tissue and is often described...... in a number of skin diseases based on pattern recognition, and studies have found good agreement between OCT images and histopathological architecture. OCT has shown high accuracy in distinguishing lesions from normal skin, which is of great importance in identifying tumour borders or residual neoplastic...

  18. Optical Coherence Tomography

    Science.gov (United States)

    Huang, David

    Optical coherence tomography (OCT) is a new method for noninvasive cross-sectional imaging in biological systems. In OCT, the longitudinal locations of tissue structures are determined by measuring the time-of-flight delays of light backscattered from these structures. The optical delays are measured by low coherence interferometry. Information on lateral position is provided by transverse scanning of the probe beam. The two dimensional map of optical scattering from internal tissue microstructures is then represented in a false-color or grayscale image. OCT is the optical analog of ultrasonic pulse-echo imaging, but with greatly improved spatial resolutions (a few microns). This thesis describes the development of this new high resolution tomographic imaging technology and the demonstration of its use in a variety of tissues under both in vitro and in vivo conditions. In vitro OCT ranging and imaging studies were performed using human ocular and arterial tissues, two clinically relevant examples of transparent and turbid media, respectively. In the anterior eye, precise measurements of cornea and anterior chamber dimensions were made. In the arterial specimens, the differentiation between fatty -calcified and fibromuscular tissues was demonstrated. In vivo OCT imaging in the retina and optic nerve head in human subjects was also performed. The delineation of retinal layers, which has not been possible with other noninvasive imaging techniques, is demonstrated in these OCT images. OCT has high spatial resolution but limited penetration into turbid tissue. It has potential for diagnostic applications where high resolution is needed and optical access is available, such as in the eye, skin, surgically exposed tissues, and surfaces that can be reached by various catheters and endoscopic probes. In particular, the measurement of fine retinal structures promises improvements in the diagnosis and management of glaucoma, macular edema and other vitreo-retinal diseases

  19. Coherence Properties of the LCLS

    Energy Technology Data Exchange (ETDEWEB)

    Ocko, Samuel

    2010-08-25

    The LINAC Coherent Light Source (LCLS), an X-Ray free-electron laser(FEL) based on the self amplified spontaneous emission principle, has recently come on-line. For many users it is desirable to have an idea of the level of transverse coherence of the X-Ray beam produced. In this paper, we analyze the output of GENESIS simulations of electrons traveling through the FEL. We first test the validity of an approach that ignores the details of how the beam was produced, and instead, by assuming a Gaussian-Schell model of transverse coherence, predicts the level of transverse coherence simply through looking at the beam radius at several longitudinal slices. We then develop a Markov chain Monte Carlo approach to calculating the degree of transverse coherence, which offers a {approx}100-fold speedup compared to the brute-force algorithm previously in use. We find the beam highly coherent. Using a similar Markov chain Monte Carlo approach, we estimate the reasonability of assuming the beam to have a Gaussian-Schell model of transverse coherence, with inconclusive results.

  20. International workshop on phase retrieval and coherent scattering. Coherence 2005

    Energy Technology Data Exchange (ETDEWEB)

    Nugent, K.A.; Fienup, J.R.; Van Dyck, D.; Van Aert, S.; Weitkamp, T.; Diaz, A.; Pfeiffer, F.; Cloetens, P.; Stampanoni, M.; Bunk, O.; David, C.; Bronnikov, A.V.; Shen, Q.; Xiao, X.; Gureyev, T.E.; Nesterets, Ya.I.; Paganin, D.M.; Wilkins, S.W.; Mokso, R.; Cloetens, P.; Ludwig, W.; Hignette, O.; Maire, E.; Faulkner, H.M.L.; Rodenburg, J.M.; Wu, X.; Liu, H.; Grubel, G.; Ludwig, K.F.; Livet, F.; Bley, F.; Simon, J.P.; Caudron, R.; Le Bolloc' h, D.; Moussaid, A.; Gutt, C.; Sprung, M.; Madsen, A.; Tolan, M.; Sinha, S.K.; Scheffold, F.; Schurtenberger, P.; Robert, A.; Madsen, A.; Falus, P.; Borthwick, M.A.; Mochrie, S.G.J.; Livet, F.; Sutton, M.D.; Ehrburger-Dolle, F.; Bley, F.; Geissler, E.; Sikharulidze, I.; Jeu, W.H. de; Lurio, L.B.; Hu, X.; Jiao, X.; Jiang, Z.; Lurio, L.B.; Hu, X.; Jiao, X.; Jiang, Z.; Naryanan, S.; Sinha, S.K.; Lal, J.; Naryanan, S.; Sinha, S.K.; Lal, J.; Robinson, I.K.; Chapman, H.N.; Barty, A.; Beetz, T.; Cui, C.; Hajdu, J.; Hau-Riege, S.P.; He, H.; Stadler, L.M.; Sepiol, B.; Harder, R.; Robinson, I.K.; Zontone, F.; Vogl, G.; Howells, M.; London, R.; Marchesini, S.; Shapiro, D.; Spence, J.C.H.; Weierstall, U.; Eisebitt, S.; Shapiro, D.; Lima, E.; Elser, V.; Howells, M.R.; Huang, X.; Jacobsen, C.; Kirz, J.; Miao, H.; Neiman, A.; Sayre, D.; Thibault, P.; Vartanyants, I.A.; Robinson, I.K.; Onken, J.D.; Pfeifer, M.A.; Williams, G.J.; Pfeiffer, F.; Metzger, H.; Zhong, Z.; Bauer, G.; Nishino, Y.; Miao, J.; Kohmura, Y.; Yamamoto, M.; Takahashi, Y.; Koike, K.; Ebisuzaki, T.; Ishikawa, T.; Spence, J.C.H.; Doak, B

    2005-07-01

    The contributions of the participants have been organized into 3 topics: 1) phase retrieval methods, 2) X-ray photon correlation spectroscopy, and 3) coherent diffraction imaging. This document gathers the abstracts of the presentations and of the posters.

  1. Coherent control of quantum dots

    DEFF Research Database (Denmark)

    Johansen, Jeppe; Lodahl, Peter; Hvam, Jørn Märcher

    In recent years much effort has been devoted to the use of semiconductor quantum dotsystems as building blocks for solid-state-based quantum logic devices. One importantparameter for such devices is the coherence time, which determines the number ofpossible quantum operations. From earlier...... measurements the coherence time of the selfassembledquantum dots (QDs) has been reported to be limited by the spontaneousemission rate at cryogenic temperatures1.In this project we propose to alter the coherence time of QDs by taking advantage of arecent technique on modifying spontaneous emission rates...

  2. Coherence in Linear Predicate Logic

    CERN Document Server

    Dosen, K

    2007-01-01

    Coherence with respect to Kelly-Mac Lane graphs is proved for categories that correspond to the multiplicative fragment without constant propositions of classical linear first-order predicate logic without or with mix. To obtain this result, coherence is first established for categories that correspond to the multiplicative conjunction-disjunction fragment with first-order quantifiers of classical linear logic, a fragment lacking negation. These results extend results published in previous two books by the authors, where coherence was established for categories of the corresponding fragments of propositional classical linear logic, which are related to proof nets, and which could be described as star-autonomous categories without unit objects.

  3. Coherent control of quantum dots

    DEFF Research Database (Denmark)

    Johansen, Jeppe; Lodahl, Peter; Hvam, Jørn Märcher

    In recent years much effort has been devoted to the use of semiconductor quantum dotsystems as building blocks for solid-state-based quantum logic devices. One importantparameter for such devices is the coherence time, which determines the number ofpossible quantum operations. From earlier...... measurements the coherence time of the selfassembledquantum dots (QDs) has been reported to be limited by the spontaneousemission rate at cryogenic temperatures1.In this project we propose to alter the coherence time of QDs by taking advantage of arecent technique on modifying spontaneous emission rates...

  4. Hybridization and Selective Release of DNA Microarrays

    Energy Technology Data Exchange (ETDEWEB)

    Beer, N R; Baker, B; Piggott, T; Maberry, S; Hara, C M; DeOtte, J; Benett, W; Mukerjee, E; Dzenitis, J; Wheeler, E K

    2011-11-29

    DNA microarrays contain sequence specific probes arrayed in distinct spots numbering from 10,000 to over 1,000,000, depending on the platform. This tremendous degree of multiplexing gives microarrays great potential for environmental background sampling, broad-spectrum clinical monitoring, and continuous biological threat detection. In practice, their use in these applications is not common due to limited information content, long processing times, and high cost. The work focused on characterizing the phenomena of microarray hybridization and selective release that will allow these limitations to be addressed. This will revolutionize the ways that microarrays can be used for LLNL's Global Security missions. The goals of this project were two-fold: automated faster hybridizations and selective release of hybridized features. The first study area involves hybridization kinetics and mass-transfer effects. the standard hybridization protocol uses an overnight incubation to achieve the best possible signal for any sample type, as well as for convenience in manual processing. There is potential to significantly shorten this time based on better understanding and control of the rate-limiting processes and knowledge of the progress of the hybridization. In the hybridization work, a custom microarray flow cell was used to manipulate the chemical and thermal environment of the array and autonomously image the changes over time during hybridization. The second study area is selective release. Microarrays easily generate hybridization patterns and signatures, but there is still an unmet need for methodologies enabling rapid and selective analysis of these patterns and signatures. Detailed analysis of individual spots by subsequent sequencing could potentially yield significant information for rapidly mutating and emerging (or deliberately engineered) pathogens. In the selective release work, optical energy deposition with coherent light quickly provides the thermal energy

  5. Pairing versus quarteting coherence length

    CERN Document Server

    Delion, Doru S

    2015-01-01

    We systematically analyse the coherence length in even-even nuclei. The pairing coherence length in the spin-singlet channel for the effective density dependent delta (DDD) and Gaussian interaction is estimated. We consider in our calculations bound states as well as narrow resonances. It turns out that the pairing gaps given by the DDD interaction are similar to those of the Gaussian potential if one renormalizes the radial width to the nuclear radius. The correlations induced by the pairing interaction have in all considered cases a long range character inside the nucleus and decrease towards the surface. The mean coherence length is larger than the geometrical radius for light nuclei and approaches this value for heavy nuclei. The effect of the temperature and states in continuum is investigated. Strong shell effects are evidenced, especially for protons. We generalize this concept to quartets by considering similar relations, but between proton and neutron pairs. The quartet coherence length has a similar...

  6. Coherent Radio Emission from Pulsars

    CERN Document Server

    Mitra, Dipanjan; Gil, Janusz

    2015-01-01

    We review a physical model where the high brightness temperature of 10$^{25}-10^{30}$ K observed in pulsar radio emission is explained by coherent curvature radiation excited in the relativistic electron-positron plasma in the pulsar magnetosphere.

  7. Coherent exciton-polariton devices

    Science.gov (United States)

    Fraser, Michael D.

    2017-09-01

    The Bose-Einstein condensate of exciton-polaritons has emerged as a unique, coherent system for the study of non-equilibrium, macroscopically coherent Bose gases, while the full confinement of this coherent state to a semiconductor chip has also generated considerable interest in developing novel applications employing the polariton condensate, possibly even at room temperature. Such devices include low-threshold lasers, precision inertial sensors, and circuits based on superfluidity with ultra-fast non-linear elements. While the demonstration and development of such devices are at an early stage, rapid progress is being made. In this review, an overview of the exciton-polariton condensate system and the established and emerging material systems and fabrication techniques are presented, followed by a critical, in-depth assessment of the ability of the coherent polariton system to deliver on its promise of devices offering either new functionality and/or room-temperature operation.

  8. Coherent Control of Bond Making

    CERN Document Server

    Levin, Liat; Rybak, Leonid; Kosloff, Ronnie; Koch, Christiane P; Amitay, Zohar

    2014-01-01

    We demonstrate for the first time coherent control of bond making, a milestone on the way to coherent control of photo-induced bimolecular chemical reactions. In strong-field multiphoton femtosecond photoassociation experiments, we find the yield of detected magnesium dimer molecules to be enhanced for positively chirped pulses and suppressed for negatively chirped pulses. Our ab initio model shows that control is achieved by purification via Franck-Condon filtering combined with chirp-dependent Raman transitions. Experimental closed-loop phase optimization using a learning algorithm yields an improved pulse that utilizes vibrational coherent dynamics in addition to chirp-dependent Raman transitions. Our results show that coherent control of binary photo-reactions is feasible even under thermal conditions.

  9. Tracking the coherent generation of polaron pairs in conjugated polymers

    Science.gov (United States)

    de Sio, Antonietta; Troiani, Filippo; Maiuri, Margherita; Réhault, Julien; Sommer, Ephraim; Lim, James; Huelga, Susana F.; Plenio, Martin B.; Rozzi, Carlo Andrea; Cerullo, Giulio; Molinari, Elisa; Lienau, Christoph

    2016-12-01

    The optical excitation of organic semiconductors not only generates charge-neutral electron-hole pairs (excitons), but also charge-separated polaron pairs with high yield. The microscopic mechanisms underlying this charge separation have been debated for many years. Here we use ultrafast two-dimensional electronic spectroscopy to study the dynamics of polaron pair formation in a prototypical polymer thin film on a sub-20-fs time scale. We observe multi-period peak oscillations persisting for up to about 1 ps as distinct signatures of vibronic quantum coherence at room temperature. The measured two-dimensional spectra show pronounced peak splittings revealing that the elementary optical excitations of this polymer are hybridized exciton-polaron-pairs, strongly coupled to a dominant underdamped vibrational mode. Coherent vibronic coupling induces ultrafast polaron pair formation, accelerates the charge separation dynamics and makes it insensitive to disorder. These findings open up new perspectives for tailoring light-to-current conversion in organic materials.

  10. Watching the coherent birth of polaron pairs in conjugated polymers

    CERN Document Server

    De Sio, Antonietta; Maiuri, Margherita; Réhault, Julien; Sommer, Ephraim; Lim, James; Huelga, Susana F; Plenio, Martin B; Rozzi, Carlo Andrea; Cerullo, Giulio; Molinari, Elisa; Lienau, Christoph

    2016-01-01

    Organic semiconductors have the remarkable property that their optical excitation not only generates charge-neutral electron-hole pairs (excitons) but also charge-separated polaron pairs with high yield. The microscopic mechanisms underlying this charge separation have been debated for many years. Here we use ultrafast two-dimensional electronic spectroscopy to study the dynamics of polaron pair formation in a prototypical polymer thin film on a sub-20-fs time scale. We observe multi-period peak oscillations persisting for up to about 1 ps as distinct signatures of vibronic quantum coherence at room temperature. The measured two-dimensional spectra show pronounced peak splittings revealing that the elementary optical excitations of this polymer are hybridized exciton-polaron-pairs, strongly coupled to a dominant underdamped vibrational mode. Coherent vibronic coupling induces ultrafast polaron pair formation, accelerates the charge separation dynamics and makes it insensitive to disorder. These findings open ...

  11. Second harmonic optical coherence tomography

    OpenAIRE

    Jiang,Yi; Tomov, Ivan; Wang, Yimin; Chen, Zhongping

    2004-01-01

    Second harmonic optical coherence tomography, which uses coherence gating of second-order nonlinear optical response of biological tissues for imaging, is described and demonstrated. Femtosecond laser pulses were used to excite second harmonic waves from collagen harvested from rat tail tendon and a reference nonlinear crystal. Second harmonic interference fringe signals were detected and used for image construction. Because of the strong dependence of second harmonic generation on molecular ...

  12. Coherence matrix of plasmonic beams

    DEFF Research Database (Denmark)

    Novitsky, Andrey; Lavrinenko, Andrei

    2013-01-01

    We consider monochromatic electromagnetic beams of surface plasmon-polaritons created at interfaces between dielectric media and metals. We theoretically study non-coherent superpositions of elementary surface waves and discuss their spectral degree of polarization, Stokes parameters, and the for...... of the spectral coherence matrix. We compare the polarization properties of the surface plasmonspolaritons as three-dimensional and two-dimensional fields concluding that the latter is superior....

  13. Coherence Studies for Synthetic Aperture Sonar

    Science.gov (United States)

    2014-09-30

    TITLE AND SUBTITLE Coherence Studies for Synthetic Aperture Sonar 5a. CONTRACT NUMBER 5b. GRANT NUMBER N00014-13-1-0020 5c. PROGRAM...systematic look at, coherence. 15. SUBJECT TERMS Synthetic; Aperture Sonar , Coherence, Seafloor Scatter, Propagation Variability 16. SECURITY...reconstruction of the document. Coherence Studies for Synthetic Aperture Sonar Anthony P. Lyons The Pennsylvania State University Applied Research

  14. (Inter)textuality, Semantics, and Coherence.

    Science.gov (United States)

    Weiser, Irwin

    Although the concept of coherence is elusive, explorations of the historical, theoretical, and empirical discussions of coherence can illuminate, though not eliminate, the concept's elusiveness. There are three inter-related and overlapping ways that readers make coherence. Intratextuality, the notion that readers perceive a text as coherent if it…

  15. A Construal Model Perspective on Discourse Coherence

    Science.gov (United States)

    Yang, Hongyan

    2015-01-01

    Discourse coherence is a common phenomenon in linguistic studies, and plays an important role in discourse analysis. As a common and extremely important type of language phenomena, discourse coherence has drawn more and more scholars' attention, but they emphasis on partial discourse coherence, paying a little attention to holistic coherence. The…

  16. Store operations to maintain cache coherence

    Energy Technology Data Exchange (ETDEWEB)

    Evangelinos, Constantinos; Nair, Ravi; Ohmacht, Martin

    2017-09-12

    In one embodiment, a computer-implemented method includes encountering a store operation during a compile-time of a program, where the store operation is applicable to a memory line. It is determined, by a computer processor, that no cache coherence action is necessary for the store operation. A store-without-coherence-action instruction is generated for the store operation, responsive to determining that no cache coherence action is necessary. The store-without-coherence-action instruction specifies that the store operation is to be performed without a cache coherence action, and cache coherence is maintained upon execution of the store-without-coherence-action instruction.

  17. Store operations to maintain cache coherence

    Energy Technology Data Exchange (ETDEWEB)

    Evangelinos, Constantinos; Nair, Ravi; Ohmacht, Martin

    2017-08-01

    In one embodiment, a computer-implemented method includes encountering a store operation during a compile-time of a program, where the store operation is applicable to a memory line. It is determined, by a computer processor, that no cache coherence action is necessary for the store operation. A store-without-coherence-action instruction is generated for the store operation, responsive to determining that no cache coherence action is necessary. The store-without-coherence-action instruction specifies that the store operation is to be performed without a cache coherence action, and cache coherence is maintained upon execution of the store-without-coherence-action instruction.

  18. Spin squeezing in nonlinear spin coherent states

    OpenAIRE

    Wang, Xiaoguang

    2001-01-01

    We introduce the nonlinear spin coherent state via its ladder operator formalism and propose a type of nonlinear spin coherent state by the nonlinear time evolution of spin coherent states. By a new version of spectroscopic squeezing criteria we study the spin squeezing in both the spin coherent state and nonlinear spin coherent state. The results show that the spin coherent state is not squeezed in the x, y, and z directions, and the nonlinear spin coherent state may be squeezed in the x and...

  19. Coherent detection of position errors in inter-satellite laser communications

    Science.gov (United States)

    Xu, Nan; Liu, Liren; Liu, De'an; Sun, Jianfeng; Luan, Zhu

    2007-09-01

    Due to the improved receiver sensitivity and wavelength selectivity, coherent detection became an attractive alternative to direct detection in inter-satellite laser communications. A novel method to coherent detection of position errors information is proposed. Coherent communication system generally consists of receive telescope, local oscillator, optical hybrid, photoelectric detector and optical phase lock loop (OPLL). Based on the system composing, this method adds CCD and computer as position error detector. CCD captures interference pattern while detection of transmission data from the transmitter laser. After processed and analyzed by computer, target position information is obtained from characteristic parameter of the interference pattern. The position errors as the control signal of PAT subsystem drive the receiver telescope to keep tracking to the target. Theoretical deviation and analysis is presented. The application extends to coherent laser rang finder, in which object distance and position information can be obtained simultaneously.

  20. Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Pier Alberto Testoni

    2007-01-01

    Full Text Available Optical coherence tomography (OCT is an optical imaging modality that performs high-resolution, cross-sectional, subsurface tomographic imaging of the microstructure of tissues. The physical principle of OCT is similar to that of B-mode ultrasound imaging, except that it uses infrared light waves rather than acoustic waves. The in vivo resolution is 10–25 times better (about 10 µm than with high-frequency ultrasound imaging, but the depth of penetration is limited to 1–3 mm, depending on tissue structure, depth of focus of the probe used, and pressure applied to the tissue surface. In the last decade, OCT technology has evolved from an experimental laboratory tool to a new diagnostic imaging modality with a wide spectrum of clinical applications in medical practice, including the gastrointestinal tract and pancreatico-biliary ductal system. OCT imaging from the gastrointestinal tract can be done in humans by using narrow-diameter, catheter-based probes that can be inserted through the accessory channel of either a conventional front-view endoscope, for investigating the epithelial structure of the gastrointestinal tract, or a side-view endoscope, inside a standard transparent ERCP (endoscopic retrograde cholangiopancreatography catheter, for investigating the pancreatico-biliary ductal system. The esophagus and esophagogastric junction have been the most widely investigated organs so far; more recently, duodenum, colon, and the pancreatico-biliary ductal system have also been extensively investigated. OCT imaging of the gastrointestinal wall structure is characterized by a multiple-layer architecture that permits an accurate evaluation of the mucosa, lamina propria, muscularis mucosae, and part of the submucosa. The technique may therefore be used to identify preneoplastic conditions of the gastrointestinal tract, such as Barrett's epithelium and dysplasia, and evaluate the depth of penetration of early-stage neoplastic lesions. OCT imaging

  1. Coherent states and applications in mathematical physics

    CERN Document Server

    Combescure, Monique

    2012-01-01

    This book presents the various types of coherent states introduced and studied in the physics and mathematics literature and describes their properties together with application to quantum physics problems. It is intended to serve as a compendium on coherent states and their applications for physicists and mathematicians, stretching from the basic mathematical structures of generalized coherent states in the sense of Perelomov via the semiclassical evolution of coherent states to various specific examples of coherent states (hydrogen atom, quantum oscillator, ...).

  2. Experimental generation of optical coherence lattices

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yahong; Cai, Yangjian, E-mail: serpo@dal.ca, E-mail: yangjiancai@suda.edu.cn [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006 (China); Ponomarenko, Sergey A., E-mail: serpo@dal.ca, E-mail: yangjiancai@suda.edu.cn [Department of Electrical and Computer Engineering, Dalhousie University, Halifax, Nova Scotia B3J 2X4 (Canada)

    2016-08-08

    We report experimental generation and measurement of recently introduced optical coherence lattices. The presented optical coherence lattice realization technique hinges on a superposition of mutually uncorrelated partially coherent Schell-model beams with tailored coherence properties. We show theoretically that information can be encoded into and, in principle, recovered from the lattice degree of coherence. Our results can find applications to image transmission and optical encryption.

  3. Coherent communication with continuous quantum variables

    Science.gov (United States)

    Wilde, Mark M.; Krovi, Hari; Brun, Todd A.

    2007-06-01

    The coherent bit (cobit) channel is a resource intermediate between classical and quantum communication. It produces coherent versions of teleportation and superdense coding. We extend the cobit channel to continuous variables by providing a definition of the coherent nat (conat) channel. We construct several coherent protocols that use both a position-quadrature and a momentum-quadrature conat channel with finite squeezing. Finally, we show that the quality of squeezing diminishes through successive compositions of coherent teleportation and superdense coding.

  4. Hybrid microelectronic technology

    Science.gov (United States)

    Moran, P.

    Various areas of hybrid microelectronic technology are discussed. The topics addressed include: basic thick film processing, thick film pastes and substrates, add-on components and attachment methods, thin film processing, and design of thick film hybrid circuits. Also considered are: packaging hybrid circuits, automating the production of hybrid circuits, application of hybrid techniques, customer's view of hybrid technology, and quality control and assurance in hybrid circuit production.

  5. Coherence measurements and coherent diffractive imaging at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Vartanyants, I A; Mancuso, A P; Singer, A; Yefanov, O M; Gulden, J, E-mail: ivan.vartaniants@desy.d [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany)

    2010-10-14

    We present an overview of recent experiments performed at the free-electron laser (FEL) FLASH at DESY in Hamburg. Experiments were focused on coherence measurements and coherent x-ray diffractive imaging (CXDI) of periodic and non-periodic biological samples. Young's double slit experiment was performed at FLASH to measure its coherence properties at a fundamental wavelength of 13.7 nm. Additionally, a uniformly redundant array was used to measure the coherence properties of the third harmonic (2.7 nm) of an 8 nm fundamental wavelength at FLASH. Coherent imaging of a two-dimensional (2D) finite crystal structure using a single pulse train of FLASH radiation was demonstrated. We show that the structure is reconstructed to the detector-limited resolution of 220 nm, given an adequate signal to noise ratio. We have also employed CXDI in a non-destructive regime to compare the images of a biological sample using single, femtosecond pulses of FLASH radiation. We have verified that images reconstructed using CXDI are similar for statistically different FEL pulses. We have also demonstrated Fourier transform holography of the same biological sample and present diffraction data measured at the third harmonic of FLASH, reaching into the water window.

  6. Modernization of the automated CARS spectrometer system based on an IBM-compatible PC

    Science.gov (United States)

    Anikeev, Boris V.; Chadaev, D. I.

    2001-05-01

    We describe the updated automated system for coherent anti- Stokes Raman spectroscopy (CARS) that includes a laser spectrometer, automatic data processing and control units, based on an IBM-compatible personal computer.

  7. Spatial Coherence of Synchrotron Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Marchesini, S; Coisson, R

    2003-10-30

    Synchrotron Radiation (SR) has been widely used since the 80's as a tool for many applications of UV, soft X rays and hard X rays in condensed matter physics, chemistry and biology. The evolution of SR sources towards higher brightness has led to the design of low-emittance electron storage rings (emittance is the product of beam size and divergence), and the development of special source magnetic structures, as undulators. This means that more and more photons are available on a narrow bandwidth and on a small collimated beam; in other words there is the possibility of getting a high power in a coherent beam. In most applications, a monochromator is used, and the temporal coherence of the light is given by the monochromator bandwidth. With smaller and smaller sources, even without the use of collimators, the spatial coherence of the light has become appreciable, first in the UV and soft X ray range, and then also with hard X rays. This has made possible new or improved experiments in interferometry, microscopy, holography, correlation spectroscopy, etc. In view of these recent possibilities and applications, it is useful to review some basic concepts about spatial coherence of SR, and its measurement and applications. In particular we show how the spatial coherence properties of the radiation in the far field can be calculated with simple operations from the single-electron amplitude and the electron beam angular and position spreads. The gaussian approximation will be studied in detail for a discussion of the properties of the far field mutual coherence and the estimate of the coherence widths, and the comparison with the VanCittert-Zernike limit.

  8. Hybridization Induced Transparency in composites of metamaterials and atomic media

    CERN Document Server

    Weis, Peter; Beigang, René; Rahm, Marco

    2011-01-01

    We report hybridization induced transparency (HIT) in a composite medium consisting of a metamaterial and a dielectric. We develop an analytic model that explains HIT by coherent coupling between the hybridized local fields of the metamaterial and the dielectric or an atomic system in general. In a proof-of-principle experiment, we evidence HIT in a split ring resonator metamaterial that is coupled to \\alpha-lactose monohydrate. Both, the analytic model and numerical calculations confirm and explain the experimental observations. HIT can be considered as a hybrid analogue to electromagnetically induced transparency (EIT) and plasmon-induced transparency (PIT).

  9. Spatial Coherence Properties of Organic Molecules Coupled to Plasmonic Surface Lattice Resonances in the Weak and Strong Coupling Regimes

    CERN Document Server

    Shi, L; Rekola, H T; Martikainen, J -P; Moerland, R J; Törmä, P

    2014-01-01

    We study spatial coherence properties of a system composed of periodic silver nanoparticle arrays covered with a fluorescent organic molecule (DiD) film. The evolution of spatial coherence of this composite structure from the weak to the strong coupling regime is investigated by systematically varying the coupling strength between the localized DiD excitons and the collective, delocalized modes of the nanoparticle array known as surface lattice resonances. A gradual evolution of coherence from the weak to the strong coupling regime is observed, with the strong coupling features clearly visible in interference fringes. A high degree of spatial coherence is demonstrated in the strong coupling regime, even when the mode is very excitonlike (80%), in contrast to the purely localized nature of molecular excitons. We show that coherence appears in proportion to the weight of the plasmonic component of the mode throughout the weak-to-strong coupling crossover, providing evidence for the hybrid nature of the normal m...

  10. Coherent states in quantum physics

    CERN Document Server

    Gazeau, Jean-Pierre

    2009-01-01

    This self-contained introduction discusses the evolution of the notion of coherent states, from the early works of Schrödinger to the most recent advances, including signal analysis. An integrated and modern approach to the utility of coherent states in many different branches of physics, it strikes a balance between mathematical and physical descriptions.Split into two parts, the first introduces readers to the most familiar coherent states, their origin, their construction, and their application and relevance to various selected domains of physics. Part II, mostly based on recent original results, is devoted to the question of quantization of various sets through coherent states, and shows the link to procedures in signal analysis. Title: Coherent States in Quantum Physics Print ISBN: 9783527407095 Author(s): Gazeau, Jean-Pierre eISBN: 9783527628292 Publisher: Wiley-VCH Dewey: 530.12 Publication Date: 23 Sep, 2009 Pages: 360 Category: Science, Science: Physics LCCN: Language: English Edition: N/A LCSH:

  11. Hybrid Gear

    Science.gov (United States)

    Handschuh, Robert F. (Inventor); Roberts, Gary D. (Inventor)

    2016-01-01

    A hybrid gear consisting of metallic outer rim with gear teeth and metallic hub in combination with a composite lay up between the shaft interface (hub) and gear tooth rim is described. The composite lay-up lightens the gear member while having similar torque carrying capability and it attenuates the impact loading driven noise/vibration that is typical in gear systems. The gear has the same operational capability with respect to shaft speed, torque, and temperature as an all-metallic gear as used in aerospace gear design.

  12. Hybrid Qualifications

    DEFF Research Database (Denmark)

    has turned out as a major focus of European education and training policies and certainly is a crucial principle underlying the European Qualifications Framework (EQF). In this context, «hybrid qualifications» (HQ) may be seen as an interesting approach to tackle these challenges as they serve «two...... masters», i.e. by producing skills for the labour market and enabling individuals to progress more or less directly to higher education. The specific focus of this book is placed on conditions, structures and processes which help to combine VET with qualifications leading into higher education...

  13. How to Drive CARS in Reverse

    Science.gov (United States)

    2013-11-07

    and ‘heats’ this plasma creating an electron avalanche , analogous to the electric discharge used in traditional nitrogen lasers. These schemes are all... pulse . This pulse is then used to drive a coherent anti-Stokes Raman scattering scheme, resulting in a strong chemically specific signal propagating...generation of a backward propagating stimulated Raman pulse . This pulse is then used to drive a coherent anti-Stokes Raman scattering scheme, resulting in a

  14. Coherent controlization using superconducting qubits.

    Science.gov (United States)

    Friis, Nicolai; Melnikov, Alexey A; Kirchmair, Gerhard; Briegel, Hans J

    2015-01-01

    Coherent controlization, i.e., coherent conditioning of arbitrary single- or multi-qubit operations on the state of one or more control qubits, is an important ingredient for the flexible implementation of many algorithms in quantum computation. This is of particular significance when certain subroutines are changing over time or when they are frequently modified, such as in decision-making algorithms for learning agents. We propose a scheme to realize coherent controlization for any number of superconducting qubits coupled to a microwave resonator. For two and three qubits, we present an explicit construction that is of high relevance for quantum learning agents. We demonstrate the feasibility of our proposal, taking into account loss, dephasing, and the cavity self-Kerr effect.

  15. Coherent fiber supercontinuum for biophotonics.

    Science.gov (United States)

    Tu, Haohua; Boppart, Stephen A

    2013-09-01

    Biophotonics and nonlinear fiber optics have traditionally been two independent fields. Since the discovery of fiber-based supercontinuum generation in 1999, biophotonics applications employing incoherent light have experienced a large impact from nonlinear fiber optics, primarily because of the access to a wide range of wavelengths and a uniform spatial profile afforded by fiber supercontinuum. However, biophotonics applications employing coherent light have not benefited from the most well-known techniques of supercontinuum generation for reasons such as poor coherence (or high noise), insufficient controllability, and inadequate portability. Fortunately, a few key techniques involving nonlinear fiber optics and femtosecond laser development have emerged to overcome these critical limitations. Despite their relative independence, these techniques are the focus of this review, because they can be integrated into a low-cost portable biophotonics source platform. This platform can be shared across many different areas of research in biophotonics, enabling new applications such as point-of-care coherent optical biomedical imaging.

  16. Coherent infrared imaging camera (CIRIC)

    Energy Technology Data Exchange (ETDEWEB)

    Hutchinson, D.P.; Simpson, M.L.; Bennett, C.A.; Richards, R.K.; Emery, M.S.; Crutcher, R.I.; Sitter, D.N. Jr.; Wachter, E.A.; Huston, M.A.

    1995-07-01

    New developments in 2-D, wide-bandwidth HgCdTe (MCT) and GaAs quantum-well infrared photodetectors (QWIP) coupled with Monolithic Microwave Integrated Circuit (MMIC) technology are now making focal plane array coherent infrared (IR) cameras viable. Unlike conventional IR cameras which provide only thermal data about a scene or target, a coherent camera based on optical heterodyne interferometry will also provide spectral and range information. Each pixel of the camera, consisting of a single photo-sensitive heterodyne mixer followed by an intermediate frequency amplifier and illuminated by a separate local oscillator beam, constitutes a complete optical heterodyne receiver. Applications of coherent IR cameras are numerous and include target surveillance, range detection, chemical plume evolution, monitoring stack plume emissions, and wind shear detection.

  17. Steerability of Quantum Coherence in Accelerated Frame

    CERN Document Server

    Mondal, Debasis

    2015-01-01

    The interplay between steering and quantum coherence is studied in a scenario, where two atoms move through an external massless scalar field. We show that just like entanglement, the steering induced coherence of the equilibrium state may increase or decrease with acceleration depending on the initial condition of the state. We also investigate the condition for coherence steerability - as opposed to simple state steerability. Interestingly, we find that the quantum coherence of the equilibrium state cannot be steered, even when the steering induced coherence is non-zero. We argue that under any condition, gravity prohibits the coherence steering of the equilibrium state.

  18. Adaptive characterization of coherent states

    Energy Technology Data Exchange (ETDEWEB)

    Stenberg, Markku P.V.; Pack, Kevin; Wilhelm, Frank K. [Theoretical Physics, Saarland University, 66123 Saarbruecken (Germany)

    2015-07-01

    We present a method for efficient characterization of an optical coherent state αright angle. We choose measurement setups adaptively based on the data while it is collected. Our algorithm divides the estimation in three different steps with different measurement strategies: (i) searching a crude estimate, (ii) rapidly improving the accuracy, and (iii) the phase where the improvement of the accuracy slows down due to the quantum nature of the coherent state. Our algorithm significantly outperforms nonadaptive schemes. While our standard strategy is robust against measurement errors we also present strategies optimized for the presence of such errors.

  19. Interference due to coherence swapping

    Indian Academy of Sciences (India)

    Arun Kumar Pati; Marek Zukowski

    2001-02-01

    We propose a method called ‘coherence swapping’ which enables us to create superposition of a particle in two distinct paths, which is fed with initially incoherent, independent radiation. This phenomenon is also present for the charged particles, and can be used to swap the effect of flux line due to the Aharonov–Bohm effect. We propose an optical version of experimental set-up to test the coherence swapping. The phenomenon, which is simpler than entanglement swapping or teleportation, raises some fundamental questions about the true nature of wave-particle duality, and also opens up the possibility of studying the quantum erasure from a new angle.

  20. Coherent broadband light source for parallel optical coherence tomography

    NARCIS (Netherlands)

    Rivier, S.; Laversenne, L.; Bourquin, S.; Salathé, R.P.; Pollnau, M.; Grivas, C.; Shepherd, D.P.; Eason, R.W.; Flury, M.; Philipoussis, I.; Herzig, H.P.

    2004-01-01

    A Ti:sapphire planar waveguide is rib structured by Ar ion milling to provide parallel channel waveguides. By coupling high-power pump light through a microlens array into the waveguides, a novel broadband luminescent parallel emitter is demonstrated as a light source for parallel optical coherence

  1. Intuitionistic hybrid logic

    DEFF Research Database (Denmark)

    Braüner, Torben

    2011-01-01

    Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area.......Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area....

  2. Continuity Controlled Hybrid Automata

    OpenAIRE

    Bergstra, J. A.; Middelburg, C.A.

    2004-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of hybrid automata as timed transition systems. We also relate the synchronized product operator on hybrid automata to the parallel composition operator of the process algebra. It turns out that the f...

  3. The suppression of coherent noise from another airgun source in marine multi-channel seismic data

    Science.gov (United States)

    Hsu, Ho-Han; Liu, Char-Shine; Chang, Jih-Hsin; Tsai, You-Tsung; Chiu, Shye-Donq

    2016-12-01

    During seismic investigations, multiple and unexpected sources may cause serious interference on seismic records, and coherent noise generated by another unwanted active source could result in extremely poor data quality. Because airgun arrays have been widely used as the sound source in marine seismic surveys, the noise generated by another airgun array usually has similar characteristics to the primary signals in both frequency bands and wave forms, so the suppression of this type of coherent noise is very difficult. In practice, seismic crews try to avoid conducting multiple surveys simultaneously in a same area, so the source interference problem normally does not occur, and suppression of coherent noise from another active source has rarely been discussed and proposed before. This paper presents a dataset in which part of the records are contaminated by shot noise from another seismic vessel, and proposes a hybrid approach to suppress the coherent noise from that unwanted seismic source. Noise subtraction and primary signal preservation within different data properties are considered to begin the noise suppression. Based on different noise characteristics from various source directions and wave propagation paths, coherence noise can be separated from primary signals in frequency-wave number (F-K), frequency-time (F-T) and intercept time-slowness (tau-p) domains, respectively. This hybrid coherent noise suppression approach involves applying three different filters, F-K, F-T and tau-p, to the contaminated dataset. Our results show that most of the coherent noise generated by another seismic source could be suppressed, and seismic images could be substantially improved.

  4. Coherence-controlled transparency and far-from-degenerate parametric gain in a strongly-absorbing Doppler-broadened medium

    CERN Document Server

    George, T F; George, Thomas F.

    2000-01-01

    An inversionless gain of anti-Stokes radiation above the oscillation threshold in an optically-dense far-from-degenerate double-Lambda Doppler-broadened medium accompanied by Stokes gain is predicted. The outcomes are illustrated with numerical simulations applied to sodium dimer vapor. Optical switching from absorption to gain via transparency controlled by a small variation of the medium and of the driving radiation parameters which are at a level less than one photon per molecule is shown.

  5. Hybridized tetraquarks

    Directory of Open Access Journals (Sweden)

    A. Esposito

    2016-07-01

    Full Text Available We propose a new interpretation of the neutral and charged X,Z exotic hadron resonances. Hybridized-tetraquarks are neither purely compact tetraquark states nor bound or loosely bound molecules but rather a manifestation of the interplay between the two. While meson molecules need a negative or zero binding energy, its counterpart for h-tetraquarks is required to be positive. The formation mechanism of this new class of hadrons is inspired by that of Feshbach metastable states in atomic physics. The recent claim of an exotic resonance in the Bs0π± channel by the D0 Collaboration and the negative result presented subsequently by the LHCb Collaboration are understood in this scheme, together with a considerable portion of available data on X,Z particles. Considerations on a state with the same quantum numbers as the X(5568 are also made.

  6. Hybridized Tetraquarks

    CERN Document Server

    Esposito, A.; Polosa, A.D.

    2016-01-01

    We propose a new interpretation of the neutral and charged X, Z exotic hadron resonances. Hybridized-tetraquarks are neither purely compact tetraquark states nor bound or loosely bound molecules. The latter would require a negative or zero binding energy whose counterpart in h-tetraquarks is a positive quantity. The formation mechanism of this new class of hadrons is inspired by that of Feshbach metastable states in atomic physics. The recent claim of an exotic resonance in the Bs pi+- channel by the D0 collaboration and the negative result presented subsequently by the LHCb collaboration are understood in this scheme, together with a considerable portion of available data on X, Z particles. Considerations on a state with the same quantum numbers as the X(5568) are also made.

  7. Neutrino production coherence and oscillation experiments

    CERN Document Server

    Akhmedov, Evgeny; Smirnov, Alexei

    2012-01-01

    Neutrino oscillations are only observable when the neutrino production, propagation and detection coherence conditions are satisfied. In this paper we consider in detail neutrino production coherence, taking \\pi\\to \\mu \

  8. Coherent states, wavelets, and their generalizations

    CERN Document Server

    Ali, Syed Twareque; Gazeau, Jean-Pierre

    2014-01-01

    This second edition is fully updated, covering in particular new types of coherent states (the so-called Gazeau-Klauder coherent states, nonlinear coherent states, squeezed states, as used now routinely in quantum optics) and various generalizations of wavelets (wavelets on manifolds, curvelets, shearlets, etc.). In addition, it contains a new chapter on coherent state quantization and the related probabilistic aspects. As a survey of the theory of coherent states, wavelets, and some of their generalizations, it emphasizes mathematical principles, subsuming the theories of both wavelets and coherent states into a single analytic structure. The approach allows the user to take a classical-like view of quantum states in physics.   Starting from the standard theory of coherent states over Lie groups, the authors generalize the formalism by associating coherent states to group representations that are square integrable over a homogeneous space; a further step allows one to dispense with the group context altoget...

  9. Optical coherent control in semiconductors

    DEFF Research Database (Denmark)

    Østergaard, John Erland; Vadim, Lyssenko; Hvam, Jørn Märcher

    2001-01-01

    of quantum control including the recent applications to semiconductors and nanostructures. We study the influence of inhomogeneous broadening in semiconductors on CC results. Photoluminescence (PL) and the coherent emission in four-wave mixing (FWM) is recorded after resonant excitation with phase...

  10. Coherent state quantization of quaternions

    Energy Technology Data Exchange (ETDEWEB)

    Muraleetharan, B., E-mail: bbmuraleetharan@jfn.ac.lk, E-mail: santhar@gmail.com [Department of Mathematics and Statistics, University of Jaffna, Thirunelveli (Sri Lanka); Thirulogasanthar, K., E-mail: bbmuraleetharan@jfn.ac.lk, E-mail: santhar@gmail.com [Department of Computer Science and Software Engineering, Concordia University, 1455 De Maisonneuve Blvd. West, Montreal, Quebec H3G 1M8 (Canada)

    2015-08-15

    Parallel to the quantization of the complex plane, using the canonical coherent states of a right quaternionic Hilbert space, quaternion field of quaternionic quantum mechanics is quantized. Associated upper symbols, lower symbols, and related quantities are analyzed. Quaternionic version of the harmonic oscillator and Weyl-Heisenberg algebra are also obtained.

  11. String effect and QCD coherence

    Energy Technology Data Exchange (ETDEWEB)

    Azimov, Ya.I.; Dokshitzer, Yu.L.; Khoze, V.A.; Troyan, S.I.

    1985-12-19

    In the framework of the idea of local parton-hadron duality we discuss the asymptotic predictions of QCD perturbation theory for angular distributions of hadron flows in the three-jet events, e/sup +/e/sup -/->qanti qg->hadrons. The coherence of soft gluon emission provides the QCD explanation of the string effect observed in experiments. (orig.).

  12. Coherent Detection of Electron Dephasing

    NARCIS (Netherlands)

    Strambini, E.; Chirolli, L.; Giovanetti, V.; Taddei, F.; Fazio, R.; Piazza, V.

    2010-01-01

    We show that an Aharonov-Bohm ring with asymmetric electron injection can act as a coherent detector of electron dephasing. The presence of a dephasing source in one of the two arms of a moderately-to-highly asymmetric ring changes the response of the system from total reflection to complete transmi

  13. Writing Quality, Coherence, and Cohesion.

    Science.gov (United States)

    McCulley, George A.

    1985-01-01

    Using a random sample of 493 persuasive papers written by 17-year-olds during the 1978-79 National Assessment of Educational Progress writing evaluation, a study investigated the relationships among features of textual cohesion and primary trait assessments of writing quality and coherence, with manuscript length held statistically constant. (HOD)

  14. Correspondence and coherence in science

    Directory of Open Access Journals (Sweden)

    Neal V. Dawson

    2009-03-01

    Full Text Available This paper introduces historical aspects of the concepts correspondence and coherence with emphasis on the nineteenth century when key aspects of modern science were emerging. It is not intended to be a definitive history of the concepts of correspondence and coherence as they have been used across the centuries in the field of inquiry that we now call science. Rather it is a brief history that highlights the apparent origins of the concepts and provides a discussion of how these concepts contributed to two important science related controversies. The first relates to aspects of evolution in which correspondence and coherence, as competing theories of truth, played a central role. The controversy about evolution continues into the beginning of the twenty-first century in forms that are recognizably similar to those of the middle of the nineteenth century. The second controversy relates to the etiology of blood-born infections (sepsis during childbirth (childbed fever. In addition to correspondence and coherence, the authors introduce other theories of truth and discuss an evolutionarily cogent theory of truth, the pragmatic theory of truth.

  15. Localized coherence of freak waves

    Science.gov (United States)

    Latifah, Arnida L.; van Groesen, E.

    2016-09-01

    This paper investigates in detail a possible mechanism of energy convergence leading to freak waves. We give examples of a freak wave as a (weak) pseudo-maximal wave to illustrate the importance of phase coherence. Given a time signal at a certain position, we identify parts of the time signal with successive high amplitudes, so-called group events, that may lead to a freak wave using wavelet transform analysis. The local coherence of the critical group event is measured by its time spreading of the most energetic waves. Four types of signals have been investigated: dispersive focusing, normal sea condition, thunderstorm condition and an experimental irregular wave. In all cases presented in this paper, it is shown that a high correlation exists between the local coherence and the appearance of a freak wave. This makes it plausible that freak waves can be developed by local interactions of waves in a wave group and that the effect of waves that are not in the immediate vicinity is minimal. This indicates that a local coherence mechanism within a wave group can be one mechanism that leads to the appearance of a freak wave.

  16. Models as coherent sign structures

    NARCIS (Netherlands)

    Gazendam, H.W.M.; Jorna, R.J.J.M.; Gazendam, H.W.M.; Cijsouw, R.S.

    2003-01-01

    This chapter explains how models function as the glue that keeps organizations together. In an analysis of models from a semiotic and cognitive point of view, assumptions about evolutionary dynamics and bounded rationality are used. It is concluded that a model is a coherent sign structure,

  17. Coaxial hybrid iron (CHI) wiggler

    Science.gov (United States)

    Jackson, Robert H.; Freund, Henry P.; Pershing, Dean E.; Taccetti, J. M.

    1993-11-01

    A magnetic wiggler design has been developed for applications in free-electron lasers which is scalable to small periods with high field amplitude, high beam current acceptance, and excellent transverse focusing and beam propagation properties. The Coaxial Hybrid Iron (CHI) wiggler design consists of a coaxial arrangement of alternating ferromagnetic and non- ferromagnetic rings with the central portion of the coax shifted by one half period. The entire arrangement is immersed in a solenoidal field which results in a cylindrically symmetric periodic field. A key advantage of this wiggler configuration is its capacity to handle very high beam currents with excellent focusing and transport properties. FEL configuration using the CHI wiggler design have the potential for high power, high frequency coherent generation in relatively compact systems. Analytic and simulated characteristics of the CHI wiggler are presented.

  18. Outage Performance of Hybrid FSO/RF System with Low-Complexity Power Adaptation

    KAUST Repository

    Rakia, Tamer

    2016-02-26

    Hybrid free-space optical (FSO) / radio-frequency (RF) systems have emerged as a promising solution for high data- rate wireless communication systems. We consider truncated channel inversion based power adaptation strategy for coherent and non- coherent hybrid FSO/RF systems, employing an adaptive combining scheme. Specifically, we activate the RF link along with the FSO link when FSO link quality is unacceptable, and adaptively set RF transmission power to ensure constant combined signal-to-noise ratio at receiver terminal. Analytical expressions for the outage probability of the hybrid system with and without power adaptation are derived. Numerical examples show that, the hybrid FSO/RF systems with power adaptation achieve considerable outage performance improvement over conventional hybrid FSO/RF systems without power adaptation. © 2015 IEEE.

  19. Coherent States with SU(N) Charges

    CERN Document Server

    Mathur, M; Mathur, Manu; Paul, Samir K.

    2003-01-01

    We define coherent states carrying SU(N) charges by exploiting generalized Schwinger boson representation of SU(N) Lie algebra. These coherent states are defined on $2 (2^{N - 1} - 1)$ complex planes. They satisfy continuity property and provide resolution of identity. We also exploit this technique to construct the corresponding non-linear SU(N) coherent states.

  20. On Radar Resolution in Coherent Change Detection.

    Energy Technology Data Exchange (ETDEWEB)

    Bickel, Douglas L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    It is commonly observed that resolution plays a role in coherent change detection. Although this is the case, the relationship of the resolution in coherent change detection is not yet defined . In this document, we present an analytical method of evaluating this relationship using detection theory. Specifically we examine the effect of resolution on receiver operating characteristic curves for coherent change detection.

  1. Correlation singularities in partially coherent electromagnetic beams

    NARCIS (Netherlands)

    Raghunathan, S.B.; Schouten, H.F.; Visser, T.D.

    2012-01-01

    We demonstrate that coherence vortices, singularities of the correlation function, generally occur in partially coherent electromagnetic beams. In successive cross sections of Gaussian Schell-model beams, their locus is found to be a closed string. These coherence singularities have implications for

  2. Evolution of a Laser Hybrid Welding Map

    Science.gov (United States)

    Kaplan, Alexander F. H.; Frostevarg, Jan; Ilar, Torbjörn; Bang, Hee-Seon; Bang, Han-Sur

    Laser arc hybrid welding combines the advantages but also the complex physical mechanisms of gas metal arc welding and laser keyhole welding. From manifold mainly experimental but also theoretical research results a map with versatile functions was initiated for the first time. The purpose is to survey the overall context and to facilitate navigation to the various phenomena that are shown through case studies accompanied by theoretical explanations and guidelines for optimization. Though not complete, the map enables systematic and graphical navigation to relevant publications. Based on a fundamental structure of the map, which was decided early, it is inherently extendable in the future by adding existing and new knowledge, also from other research groups, enabling evolution. The fundament of the map structure comprises gouge thickness, joint type and metal grade, in coherence with product and weld designers' starting points. The next hierarchy level of the map offers options in the joint type as well as in hybrid welding techniques. The latter contains techniques like double-sided welding, pulse shaping management of the arc or laser, CMT arcs, tandem arcs, or remelting of undercuts. In addition to laser-arc hybrid welding, other hybrid laser techniques like multilayer hot-wire laser welding of narrow gaps or hybrid laser friction stir welding can be taken into account. At the other end of the hierarchy, the map offers via a database-like archive electronic navigation to research results like weld macrographs, high speed imaging or numerical simulation results of the welding process.

  3. Continuity Controlled Hybrid Automata

    NARCIS (Netherlands)

    Bergstra, J.A.; Middelburg, C.A.

    2004-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

  4. Continuity controlled Hybrid Automata

    NARCIS (Netherlands)

    Bergstra, J.A.; Middelburg, C.A.

    2008-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

  5. Linear algebraic theory of partial coherence: continuous fields and measures of partial coherence.

    Science.gov (United States)

    Ozaktas, Haldun M; Gulcu, Talha Cihad; Alper Kutay, M

    2016-11-01

    This work presents a linear algebraic theory of partial coherence for optical fields of continuous variables. This approach facilitates use of linear algebraic techniques and makes it possible to precisely define the concepts of incoherence and coherence in a mathematical way. We have proposed five scalar measures for the degree of partial coherence. These measures are zero for incoherent fields, unity for fully coherent fields, and between zero and one for partially coherent fields.

  6. Characterisation of dispersive systems using a coherer

    Directory of Open Access Journals (Sweden)

    Nikolić Pantelija M.

    2002-01-01

    Full Text Available The possibility of characterization of aluminium powders using a horizontal coherer has been considered. Al powders of known dimension were treated with a high frequency electromagnetic field or with a DC electric field, which were increased until a dielectric breakdown occurred. Using a multifunctional card PC-428 Electronic Design and a suitable interface between the coherer and PC, the activation time of the coherer was measured as a function of powder dimension and the distance between the coherer electrodes. It was also shown that the average dimension of powders of unknown size could be determined using the coherer.

  7. Quantum coherence and correlations in quantum system

    Science.gov (United States)

    Xi, Zhengjun; Li, Yongming; Fan, Heng

    2015-01-01

    Criteria of measure quantifying quantum coherence, a unique property of quantum system, are proposed recently. In this paper, we first give an uncertainty-like expression relating the coherence and the entropy of quantum system. This finding allows us to discuss the relations between the entanglement and the coherence. Further, we discuss in detail the relations among the coherence, the discord and the deficit in the bipartite quantum system. We show that, the one-way quantum deficit is equal to the sum between quantum discord and the relative entropy of coherence of measured subsystem. PMID:26094795

  8. Energy cost of creating quantum coherence

    Science.gov (United States)

    Misra, Avijit; Singh, Uttam; Bhattacharya, Samyadeb; Pati, Arun Kumar

    2016-05-01

    We consider physical situations where the resource theories of coherence and thermodynamics play competing roles. In particular, we study the creation of quantum coherence using unitary operations with limited thermodynamic resources. We find the maximal coherence that can be created under unitary operations starting from a thermal state and find explicitly the unitary transformation that creates the maximal coherence. Since coherence is created by unitary operations starting from a thermal state, it requires some amount of energy. This motivates us to explore the trade-off between the amount of coherence that can be created and the energy cost of the unitary process. We also find the maximal achievable coherence under the constraint on the available energy. Additionally, we compare the maximal coherence and the maximal total correlation that can be created under unitary transformations with the same available energy at our disposal. We find that when maximal coherence is created with limited energy, the total correlation created in the process is upper bounded by the maximal coherence, and vice versa. For two-qubit systems we show that no unitary transformation exists that creates the maximal coherence and maximal total correlation simultaneously with a limited energy cost.

  9. Vibrational and coherence dynamics of molecules

    CERN Document Server

    Zhang, Zhedong

    2015-01-01

    We {\\it analytically} investigate the population and coherence dynamics and relaxations in the vibrational energy transport in molecules. The corresponding two time scales $t_1$ and $t_2$ are explored. Coherence-population entanglement is found to considerably promote the time scale $t_2$ for dephasing and the amplitude of coherence. This is attributed to the suppression of the environment-induced drift force by coherence. Moreover the population imbalance (magnetization) is shown to be significantly amplified with the coherence-population entanglement. Contrary to the previous studies, we exactly elucidate a coherent process by showing $t_1coherence effect on the heat current at the macroscopic level.

  10. Coherent Communication with Continuous Quantum Variables

    CERN Document Server

    Wilde, M M; Krovi, H; Brun, Todd A.; Krovi, Hari; Wilde, Mark M.

    2006-01-01

    The coherent bit (cobit) channel is a resource intermediate between classical communication and quantum communication. The cobit channel produces coherent versions of the teleportation and superdense coding protocols. We extend the cobit channel to the continuous variables of quantum optics. We provide a general definition of the ``coherent nat'' (conat) channel when only finite-squeezing resources are available. Coherent teleportation provides sufficient conditions and coherent superdense coding provides necessary conditions for a channel to be a finite-squeezing approximation to an ideal conat channel. We illustrate several protocols that use both a position-quadrature and a momentum-quadrature conat channel. Finally, we address the reversibility of coherent teleportation and coherent superdense coding with only finite-squeezing resources.

  11. Coherent phase argument for inflation

    Energy Technology Data Exchange (ETDEWEB)

    Scott Dodelson

    2004-03-17

    Cosmologists have developed a phenomenally successful picture of structure in the universe based on the idea that the universe expanded exponentially in its earliest moments. There are three pieces of evidence for this exponential expansion--inflation--from observations of anisotropies in the cosmic microwave background. First, the shape of the primordial spectrum is very similar to that predicted by generic inflation models. Second, the angular scale at which the first acoustic peak appears is consistent with the flat universe predicted by inflation. Here the author describes the third piece of evidence, perhaps the most convincing of all: the phase coherence needed to account for the clear peak/trough structure observed by the WMAP satellite and its predecessors. The author also discusses alternatives to inflation that have been proposed recently and explain how they produce coherent phases.

  12. Detecting coherent structures using braids

    CERN Document Server

    Allshouse, Michael R

    2011-01-01

    The detection of coherent structures is an important problem in fluid dynamics, particularly in geophysical applications. For instance, knowledge of how regions of fluid are isolated from each other allows prediction of the ultimate fate of oil spills. Existing methods detect Lagrangian coherent structures, which are barriers to transport, by examining the stretching field as given by finite-time Lyapunov exponents. These methods are very effective when the velocity field is well-determined, but in many applications only a small number of flow trajectories are known, for example when dealing with oceanic float data. We introduce a topological method for detecting invariant regions based on a small set of trajectories. In the method we regard the two-dimensional trajectory data as a braid in three dimensions, with time being the third coordinate. Invariant regions then correspond to trajectories that travel together and do not entangle other trajectories. We detect these regions by examining the growth of hypo...

  13. Coherent optical methods for metallography

    Energy Technology Data Exchange (ETDEWEB)

    Pechersky, M.J.

    1991-01-01

    Numerous methods based on coherent optical techniques have been developed over the past two decades for nondestructive evaluation, vibration analysis and experimental mechanics. These methods have a great deal of potential for the enhancement of metallographic evaluations and for materials characterization in general. One such technique described in this paper is the determination of the material damping factors in metals. Damping loss factors as low as 10-5 were measured on bronze and aluminum specimens using a technique based on laser vibrometry. Differences between cast and wrought bronze were easily distinguishable as well as the difference between the bronze and aluminum. Other coherent optical techniques may be used to evaluate residual stresses and to locate and identify microcracking, subsurface voids and other imperfections. These techniques and others can serve as a bridge between microstructural investigations and the macroscopic behavior of materials.

  14. Coherent optical methods for metallography

    Energy Technology Data Exchange (ETDEWEB)

    Pechersky, M.J.

    1991-12-31

    Numerous methods based on coherent optical techniques have been developed over the past two decades for nondestructive evaluation, vibration analysis and experimental mechanics. These methods have a great deal of potential for the enhancement of metallographic evaluations and for materials characterization in general. One such technique described in this paper is the determination of the material damping factors in metals. Damping loss factors as low as 10-5 were measured on bronze and aluminum specimens using a technique based on laser vibrometry. Differences between cast and wrought bronze were easily distinguishable as well as the difference between the bronze and aluminum. Other coherent optical techniques may be used to evaluate residual stresses and to locate and identify microcracking, subsurface voids and other imperfections. These techniques and others can serve as a bridge between microstructural investigations and the macroscopic behavior of materials.

  15. Remote creation of quantum coherence

    Science.gov (United States)

    Ma, Teng; Zhao, Ming-Jing; Fei, Shao-Ming; Long, Gui-Lu

    2016-10-01

    We study remote creation of coherence (RCC) for a quantum system, A, with the help of quantum operations on another system, B, and one-way classical communication. We show that all the nonincoherent quantum states are useful for RCC and all the incoherent-quantum states are not. The necessary and sufficient conditions of RCC for the quantum operations on system B are presented for pure states. The upper bound of average RCC is derived, giving a relation among the entanglement (concurrence), the RCC of the given quantum state, and the RCC of the corresponding maximally entangled state. Moreover, for two-qubit systems we find a simple factorization law for the average remote-created coherence.

  16. Quantum coherence in photosynthetic complexes

    Energy Technology Data Exchange (ETDEWEB)

    Calhoun, Tessa R.; Fleming, Graham R. [Department of Chemistry, University of California, Berkeley, CA 94720 (United States); Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2011-04-15

    The initial steps of photosynthesis require the absorption and subsequent transfer of energy through an intricate network of pigment-protein complexes. Held within the protein scaffold of these complexes, chromophore molecules are densely packed and fixed in specific geometries relative to one another resulting in Coulombic coupling. Excitation energy transfer through these systems can be accomplished with near unity quantum efficiency [Wraight and Clayton, Biochim. Biophys. Acta 333, 246 (1974)]. While replication of this feat is desirable for artificial photosynthesis, the mechanism by which nature achieves this efficiency is unknown. Recent experiments have revealed the presence of long-lived quantum coherences in photosynthetic pigment-protein complexes spanning bacterial and plant species with a variety of functions and compositions. Its ubiquitous presence and wavelike energy transfer implicate quantum coherence as key to the high efficiency achieved by photosynthesis. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Photoelectric converters with quantum coherence

    Science.gov (United States)

    Su, Shan-He; Sun, Chang-Pu; Li, Sheng-Wen; Chen, Jin-Can

    2016-05-01

    Photon impingement is capable of liberating electrons in electronic devices and driving the electron flux from the lower chemical potential to higher chemical potential. Previous studies hinted that the thermodynamic efficiency of a nanosized photoelectric converter at maximum power is bounded by the Curzon-Ahlborn efficiency ηCA. In this study, we apply quantum effects to design a photoelectric converter based on a three-level quantum dot (QD) interacting with fermionic baths and photons. We show that, by adopting a pair of suitable degenerate states, quantum coherences induced by the couplings of QDs to sunlight and fermion baths can coexist steadily in nanoelectronic systems. Our analysis indicates that the efficiency at maximum power is no longer limited to ηCA through manipulation of carefully controlled quantum coherences.

  18. Wavefront sensing reveals optical coherence.

    Science.gov (United States)

    Stoklasa, B; Motka, L; Rehacek, J; Hradil, Z; Sánchez-Soto, L L

    2014-01-01

    Wavefront sensing is a set of techniques providing efficient means to ascertain the shape of an optical wavefront or its deviation from an ideal reference. Owing to its wide dynamical range and high optical efficiency, the Shack-Hartmann wavefront sensor is nowadays the most widely used of these sensors. Here we show that it actually performs a simultaneous measurement of position and angular spectrum of the incident radiation and, therefore, when combined with tomographic techniques previously developed for quantum information processing, the Shack-Hartmann wavefront sensor can be instrumental in reconstructing the complete coherence properties of the signal. We confirm these predictions with an experimental characterization of partially coherent vortex beams, a case that cannot be treated with the standard tools. This seems to indicate that classical methods employed hitherto do not fully exploit the potential of the registered data.

  19. Neutrino induced coherent pion production

    CERN Document Server

    Hernández, E; Valverde, M; Vicente-Vacas, M J

    2009-01-01

    We discuss different parameterizations of the $C_5^A(q^2)$ $N\\Delta$ axial form factor, fitted to the old Argonne bubble chamber data for pion production by neutrinos, and we use coherent pion production to test their low $q^2$ behavior. We find moderate effects that will be difficult to observe with the accuracy of present experiments. We also discuss the use of the Rein-Sehgal model for low energy coherent pion production. By comparison to a microscopic calculation, we show the weaknesses of some of the approximations in that model that lead to very large cross sections as well as to the wrong shapes for differential ones. Finally we show that models based on the partial conservation of the axial current hypothesis are not fully reliable for differential cross sections that depend on the angle formed by the pion and the incident neutrino.

  20. How coherent are Josephson junctions?

    CERN Document Server

    Paik, Hanhee; Bishop, Lev S; Kirchmair, G; Catelani, G; Sears, A P; Johnson, B R; Reagor, M J; Frunzio, L; Glazman, L; Schoelkopf, R J

    2011-01-01

    Attaining sufficient coherence is a requirement for realizing a large-scale quantum computer. We present a new implementation of a superconducting transmon qubit that is strongly coupled to a three-dimensional superconducting cavity. We observe a reproducible increase in the coherence times of qubit (both $T_1$ and $T_2$ > 10 microseconds) and cavity ($T_{cav}$ ~ 50 microseconds) by more than an order of magnitude compared to the current state-of-art superconducting qubits. This enables the study of the stability and quality of Josephson junctions at precisions exceeding one part per million. Surprisingly, we see no evidence for $1/f$ critical current noise. At elevated temperatures, we observe the dissipation due to a small density (< 1 - 10 ppm) of thermally-excited quasiparticles. The results suggest that the overall quality of Josephson junctions will allow error rates of a few $10^{-4}$, approaching the error correction threshold.

  1. Photoelectric converters with quantum coherence.

    Science.gov (United States)

    Su, Shan-He; Sun, Chang-Pu; Li, Sheng-Wen; Chen, Jin-Can

    2016-05-01

    Photon impingement is capable of liberating electrons in electronic devices and driving the electron flux from the lower chemical potential to higher chemical potential. Previous studies hinted that the thermodynamic efficiency of a nanosized photoelectric converter at maximum power is bounded by the Curzon-Ahlborn efficiency η_{CA}. In this study, we apply quantum effects to design a photoelectric converter based on a three-level quantum dot (QD) interacting with fermionic baths and photons. We show that, by adopting a pair of suitable degenerate states, quantum coherences induced by the couplings of QDs to sunlight and fermion baths can coexist steadily in nanoelectronic systems. Our analysis indicates that the efficiency at maximum power is no longer limited to η_{CA} through manipulation of carefully controlled quantum coherences.

  2. The global coherence initiative: creating a coherent planetary standing wave.

    Science.gov (United States)

    McCraty, Rollin; Deyhle, Annette; Childre, Doc

    2012-03-01

    The much anticipated year of 2012 is now here. Amidst the predictions and cosmic alignments that many are aware of, one thing is for sure: it will be an interesting and exciting year as the speed of change continues to increase, bringing both chaos and great opportunity. One benchmark of these times is a shift in many people from a paradigm of competition to one of greater cooperation. All across the planet, increasing numbers of people are practicing heart-based living, and more groups are forming activities that support positive change and creative solutions for manifesting a better world. The Global Coherence Initiative (GCI) is a science-based, co-creative project to unite people in heart-focused care and intention. GCI is working in concert with other initiatives to realize the increased power of collective intention and consciousness. The convergence of several independent lines of evidence provides strong support for the existence of a global information field that connects all living systems and consciousness. Every cell in our bodies is bathed in an external and internal environment of fluctuating invisible magnetic forces that can affect virtually every cell and circuit in biological systems. Therefore, it should not be surprising that numerous physiological rhythms in humans and global collective behaviors are not only synchronized with solar and geomagnetic activity, but disruptions in these fields can create adverse effects on human health and behavior. The most likely mechanism for explaining how solar and geomagnetic influences affect human health and behavior are a coupling between the human nervous system and resonating geomagnetic frequencies, called Schumann resonances, which occur in the earth-ionosphere resonant cavity and Alfvén waves. It is well established that these resonant frequencies directly overlap with those of the human brain and cardiovascular system. If all living systems are indeed interconnected and communicate with each other

  3. Classical Coherence, Life and Consciousness

    Science.gov (United States)

    Ghose, Partha

    2014-07-01

    There have been many claims that quantum mechanics plays a key role in the origin and/or operation of biological organisms, beyond merely providing the basis for the shapes and sizes of biological molecules and their chemical affinities. These range from Schrödinger's suggestion that quantum fluctuations produce mutations, to Hameroff and Penrose's conjecture that quantum coherence in microtubules is linked to consciousness. I review some of these claims in this paper, and discuss the serious problem of decoherence.

  4. Hanle effect in coherent backscattering

    CERN Document Server

    Labeyrie, G; Müller, C A; Sigwarth, O; Delande, D; Kaiser, R

    2002-01-01

    We study the shape of the coherent backscattering (CBS) cone obtained when resonant light illuminates a thick cloud of laser-cooled rubidium atoms in presence of a homogenous magnetic field. We observe new magnetic field-dependent anisotropies in the CBS signal. We show that the observed behavior is due to the modification of the atomic radiation pattern by the magnetic field (Hanle effect in the excited state).

  5. Scattering and coherence in EUVL

    Science.gov (United States)

    Milster, Tomas D.; Beaudry, Neil A.

    1998-06-01

    We illustrate the importance of considering scattering from the illuminator in extreme UV lithography systems. Our results indicate that a significant amount of amplitude modulation noise is present in the aerial image if scatter is present in a Koehler illuminator. The effect depends on the spatial frequency of the pattern on the mask, the numerical aperture of the projection camera, the coherence factor, and placement of the plane in the illuminator where the scattering occurs.

  6. Spin coherence time analytical estimations

    CERN Document Server

    Orlov, Yuri

    2015-01-01

    Section I presents a variety of analytical estimations related to spin coherence time (SCT) in a purely electric frozen-spin ring. The main result is that, in the case of m > 0 and vertical oscillations only, the kinetic energy equilibrium shift equals zero, that is, SCT does not depend on these oscillations. Section II contains additional information on this case concerning terminology, electric field definition and vertical oscillations.

  7. Coherent Transfer between Low-Angular-Momentum and Circular Rydberg States

    Science.gov (United States)

    Signoles, A.; Dietsche, E. K.; Facon, A.; Grosso, D.; Haroche, S.; Raimond, J. M.; Brune, M.; Gleyzes, S.

    2017-06-01

    We realize a coherent transfer between a laser-accessible low-angular-momentum Rydberg state and the circular Rydberg level with maximal angular momentum. It is induced by a radio frequency field with a high-purity σ+ polarization resonant on Stark transitions inside the hydrogenic Rydberg manifold. We observe over a few microseconds more than 20 coherent Rabi oscillations between the initial Rydberg state and the circular level. We characterize these many-Rydberg-level oscillations and find them in perfect agreement with a simple model. This coherent transfer opens the way to hybrid quantum gates bridging the gap between optical communication and quantum information manipulations with microwave cavity and circuit quantum electrodynamics.

  8. Complete Coherent Control of a Quantum Dot Strongly Coupled to a Nanocavity

    Science.gov (United States)

    Dory, Constantin; Fischer, Kevin A.; Müller, Kai; Lagoudakis, Konstantinos G.; Sarmiento, Tomas; Rundquist, Armand; Zhang, Jingyuan L.; Kelaita, Yousif; Vučković, Jelena

    2016-01-01

    Strongly coupled quantum dot-cavity systems provide a non-linear configuration of hybridized light-matter states with promising quantum-optical applications. Here, we investigate the coherent interaction between strong laser pulses and quantum dot-cavity polaritons. Resonant excitation of polaritonic states and their interaction with phonons allow us to observe coherent Rabi oscillations and Ramsey fringes. Furthermore, we demonstrate complete coherent control of a quantum dot-photonic crystal cavity based quantum-bit. By controlling the excitation power and phase in a two-pulse excitation scheme we achieve access to the full Bloch sphere. Quantum-optical simulations are in good agreement with our experiments and provide insight into the decoherence mechanisms. PMID:27112420

  9. Quantum learning of coherent states

    CERN Document Server

    Sentís, Gael; Adesso, Gerardo

    2014-01-01

    We develop a quantum learning scheme for binary discrimination of coherent states of light. This is a problem of technological relevance for the reading of information stored in a digital memory. In our setting, a coherent light source is used to illuminate a memory cell and retrieve its encoded bit by determining the quantum state of the reflected signal. We consider a situation where the amplitude of the states produced by the source is not fully known, but instead this information is encoded in a large training set comprising many copies of the same coherent state. We show that an optimal global measurement, performed jointly over the signal and the training set, provides higher successful identification rates than any learning strategy based on first estimating the unknown amplitude by means of Gaussian measurements on the training set, followed by an adaptive discrimination procedure on the signal. By considering a simplified variant of the problem, we argue that this is the case even for non-Gaussian es...

  10. Quantum learning of coherent states

    Energy Technology Data Exchange (ETDEWEB)

    Sentis, Gael [Universitat Autonoma de Barcelona, Fisica Teorica: Informacio i Fenomens Quantics, Barcelona (Spain); Guta, Madalin; Adesso, Gerardo [University of Nottingham, School of Mathematical Sciences, Nottingham (United Kingdom)

    2015-12-15

    We develop a quantum learning scheme for binary discrimination of coherent states of light. This is a problem of technological relevance for the reading of information stored in a digital memory. In our setting, a coherent light source is used to illuminate a memory cell and retrieve its encoded bit by determining the quantum state of the reflected signal. We consider a situation where the amplitude of the states produced by the source is not fully known, but instead this information is encoded in a large training set comprising many copies of the same coherent state. We show that an optimal global measurement, performed jointly over the signal and the training set, provides higher successful identification rates than any learning strategy based on first estimating the unknown amplitude by means of Gaussian measurements on the training set, followed by an adaptive discrimination procedure on the signal. By considering a simplified variant of the problem, we argue that this is the case even for non-Gaussian estimation measurements. Our results show that, even in absence of entanglement, collective quantum measurements yield an enhancement in the readout of classical information, which is particularly relevant in the operating regime of low-energy signals. (orig.)

  11. Discrete Coherent State Path Integrals

    Science.gov (United States)

    Marchioro, Thomas L., II

    1990-01-01

    The quantum theory provides a fundamental understanding of the physical world; however, as the number of degrees of freedom rises, the information required to specify quantum wavefunctions grows geometrically. Because basis set expansions mirror this geometric growth, a strict practical limit on quantum mechanics as a numerical tool arises, specifically, three degrees of freedom or fewer. Recent progress has been made utilizing Feynman's Path Integral formalism to bypass this geometric growth and instead calculate time -dependent correlation functions directly. The solution of the Schrodinger equation is converted into a large dimensional (formally infinite) integration, which can then be attacked with Monte Carlo techniques. To date, work in this area has concentrated on developing sophisticated mathematical algorithms for evaluating the highly oscillatory integrands occurring in Feynman Path Integrals. In an alternative approach, this work demonstrates two formulations of quantum dynamics for which the number of mathematical operations does not scale geometrically. Both methods utilize the Coherent State basis of quantum mechanics. First, a localized coherent state basis set expansion and an approximate short time propagator are developed. Iterations of the short time propagator lead to the full quantum dynamics if the coherent state basis is sufficiently dense along the classical phase space path of the system. Second, the coherent state path integral is examined in detail. For a common class of Hamiltonians, H = p^2/2 + V( x) the path integral is reformulated from a phase space-like expression into one depending on (q,dot q). It is demonstrated that this new path integral expression contains localized damping terms which can serve as a statistical weight for Monte Carlo evaluation of the integral--a process which scales approximately linearly with the number of degrees of freedom. Corrections to the traditional coherent state path integral, inspired by a

  12. Coherent Charge Transport in Ballistic InSb Nanowire Josephson Junctions

    Science.gov (United States)

    Li, S.; Kang, N.; Fan, D. X.; Wang, L. B.; Huang, Y. Q.; Caroff, P.; Xu, H. Q.

    2016-04-01

    Hybrid InSb nanowire-superconductor devices are promising for investigating Majorana modes and topological quantum computation in solid-state devices. An experimental realisation of ballistic, phase-coherent superconductor-nanowire hybrid devices is a necessary step towards engineering topological superconducting electronics. Here, we report on a low-temperature transport study of Josephson junction devices fabricated from InSb nanowires grown by molecular-beam epitaxy and provide a clear evidence for phase-coherent, ballistic charge transport through the nanowires in the junctions. We demonstrate that our devices show gate-tunable proximity-induced supercurrent and clear signatures of multiple Andreev reflections in the differential conductance, indicating phase-coherent transport within the junctions. We also observe periodic modulations of the critical current that can be associated with the Fabry-Pérot interference in the nanowires in the ballistic transport regime. Our work shows that the InSb nanowires grown by molecular-beam epitaxy are of excellent material quality and hybrid superconducting devices made from these nanowires are highly desirable for investigation of the novel physics in topological states of matter and for applications in topological quantum electronics.

  13. Maximal coherence in a generic basis

    Science.gov (United States)

    Yao, Yao; Dong, G. H.; Ge, Li; Li, Mo; Sun, C. P.

    2016-12-01

    Since quantum coherence is an undoubted characteristic trait of quantum physics, the quantification and application of quantum coherence has been one of the long-standing central topics in quantum information science. Within the framework of a resource theory of quantum coherence proposed recently, a fiducial basis should be preselected for characterizing the quantum coherence in specific circumstances, namely, the quantum coherence is a basis-dependent quantity. Therefore, a natural question is raised: what are the maximum and minimum coherences contained in a certain quantum state with respect to a generic basis? While the minimum case is trivial, it is not so intuitive to verify in which basis the quantum coherence is maximal. Based on the coherence measure of relative entropy, we indicate the particular basis in which the quantum coherence is maximal for a given state, where the Fourier matrix (or more generally, complex Hadamard matrices) plays a critical role in determining the basis. Intriguingly, though we can prove that the basis associated with the Fourier matrix is a stationary point for optimizing the l1 norm of coherence, numerical simulation shows that it is not a global optimal choice.

  14. Total quantum coherence and its applications

    Science.gov (United States)

    Yu, Chang-shui; Yang, Si-ren; Guo, Bao-qing

    2016-09-01

    Quantum coherence is the most fundamental feature of quantum mechanics. The usual understanding of it depends on the choice of the basis, that is, the coherence of the same quantum state is different within different reference framework. To reveal all the potential coherence, we present the total quantum coherence measures in terms of two different methods. One is optimizing maximal basis-dependent coherence with all potential bases considered and the other is quantifying the distance between the state and the incoherent state set. Interestingly, the coherence measures based on relative entropy and l_2 norm have the same form in the two different methods. In particular, we show that the measures based on the non-contractive l_2 norm are also a good measure different from the basis-dependent coherence. In addition, we show that all the measures are analytically calculable and have all the good properties. The experimental schemes for the detection of these coherence measures are also proposed by multiple copies of quantum states instead of reconstructing the full density matrix. By studying one type of quantum probing schemes, we find that both the normalized trace in the scheme of deterministic quantum computation with one qubit and the overlap of two states in quantum overlap measurement schemes can be well described by the change of total coherence of the probing qubit. Hence the nontrivial probing always leads to the change of the total coherence.

  15. Robustness of coherence: An operational and observable measure of quantum coherence

    CERN Document Server

    Napoli, Carmine; Cianciaruso, Marco; Piani, Marco; Johnston, Nathaniel; Adesso, Gerardo

    2016-01-01

    Quantifying coherence is an essential endeavour for both quantum foundations and quantum technologies. Here the robustness of coherence is defined and proven a full monotone in the context of the recently introduced resource theories of quantum coherence. The measure is shown to be observable, as it can be recast as the expectation value of a coherence witness operator for any quantum state. The robustness of coherence is evaluated analytically on relevant classes of states, and an efficient semidefinite program that computes it on general states is given. An operational interpretation is finally provided: the robustness of coherence quantifies the advantage enabled by a quantum state in a phase-discrimination task.

  16. Use of discrete Wigner functions in the study of a hybrid dissipative system

    Science.gov (United States)

    Reboiro, M.; Civitarese, O.; Ramirez, R.; Tielas, D.

    2017-09-01

    The persistence of coherence in a hybrid dissipative system, which is composed of superconducting flux-qubits (SFQs) and an electron ensemble, is analyzed. Both the interactions between the electrons and the SFQs are taken into account. The time evolution of the hybrid system is discussed in terms of the discrete Wigner function of each subsystem and in terms of the entropic uncertainty relations. The inclusion of a linewidth, both for the electrons and the SFQs, influences the coherence of each subsystem and the pattern of spin squeezing of the corresponding steady state.

  17. Hybrid lidar radar receiver for underwater imaging applications

    Science.gov (United States)

    Seetamraju, Madhavi; Gurjar, Rajan; Squillante, Michael; Derderian, Jeffrey P.

    2009-05-01

    In this work, we present research performed to improve the receiver characteristics for underwater imaging applications using the hybrid lidar-radar detection technique. We report the development of the next-generation coherent heterodyne receiver using modulation of the optical receiver's amplifier gain. Significant advantages in the receiver specifications are achieved using a large-area, high gain, low-noise silicon avalanche photodiode (APD) as the photodetector cum frequency mixer-demodulator. We demonstrate that heterodyne detection by gain modulation of APD can be used to increase the signal-to-noise ratio, detection sensitivity and bandwidth for the hybrid receiver system.

  18. Does coherence enhance transport in photosynthesis?

    CERN Document Server

    Kassal, Ivan; Rahimi-Keshari, Saleh

    2012-01-01

    Recent observations of coherence in photosynthetic complexes have led to the question of whether quantum effects can occur in vivo, not under femtosecond laser pulses but in incoherent sunlight and at steady state, and, if so, whether the coherence explains the high exciton transfer efficiency. We distinguish several types of coherence and show that although some photosynthetic pathways are partially coherent processes, photosynthesis in nature proceeds through stationary states. This distinction allows us to rule out several mechanisms of transport enhancement in sunlight. In particular, although they are crucial for understanding exciton transport, neither wavelike motion nor microscopic coherence, on their own, enhance the efficiency. By contrast, two partially coherent mechanisms---ENAQT and supertransfer---can enhance transport even in sunlight and thus constitute motifs for the optimisation of artificial sunlight harvesting. Finally, we clarify the importance of ultrafast spectroscopy in understanding i...

  19. Is a coherence theory of understanding possible?

    Directory of Open Access Journals (Sweden)

    Victor Gijsbers

    2015-03-01

    Full Text Available Coherence is a measure of how much our beliefs hang together. Understanding is achieved when we see that something is not just a brute, isolated fact. This suggests that it might be possible to develop a coherence theory of understanding, which is what we attempt to do in this article using several formal measures of coherence. However, it turns out that a coherence theory runs into trouble with the asymmetry of understanding. We identify four difficulties and give suggestions for how they could be solved. These solutions all point away from coherence and towards a rather different notion, unification, which casts some (though not conclusive doubt on the possibility of a coherence theory of understanding.

  20. Can Natural Sunlight Induce Coherent Exciton Dynamics?

    CERN Document Server

    Olšina, Jan; Wang, Chen; Cao, Jianshu

    2014-01-01

    Excitation of a model photosynthetic molecular aggregate by incoherent sunlight is systematically examined. For a closed system, the excited state coherence induced by the sunlight oscillates with an average amplitude that is inversely proportional to the excitonic gap, and reaches a stationary amplitude that depends on the temperature and coherence time of the radiation field. For an open system, the light-induced dynamical coherence relaxes to a static coherence determined by the non-canonical thermal distribution resulting from the entanglement with the phonon bath. The decay of the excited state population to the common ground state establishes a non-equilibrium steady-state flux driven by the sunlight, and it defines a time window to observe the transition from dynamical to static coherence. For the parameters relevant to photosynthetic systems, the exciton dynamics initiated by the sunlight exhibits a non-negligible amount of dynamical coherence (quantum beats) on the sub-picosecond timescale; however, ...

  1. Coherent lunar effect on solar neutrino

    CERN Document Server

    Ishikawa, K

    2005-01-01

    Coherent interaction of solar neutrino with the moon is investigated. Neutrino interacts with matters extremely weakly. So incoherent scattering event rate is negligibly small but coherent interaction of neutrino with a massive object can have a significant effect. We study coherent lunar effect on solar neutrino and show that a phase factor of the neutrino wave function is modified substantially if the neutrino penetrates through the moon. Possibility of measuring interference effect of solar neutrino during eclipse is pointed out.

  2. Operator properties of generalized coherent state systems

    Indian Academy of Sciences (India)

    N Mukunda

    2001-02-01

    The main properties of standard quantum mechanical coherent states and the two generalizations of Klauder and of Perelomov are reviewed. For a system of generalized coherent states in the latter sense, necessary and sufficient conditions for existence of a diagonal coherent stable representation for all Hilbert-Schmidt operators are obtained. The main ingredients are Clebsch-Gordan theory and induced representation theory.

  3. Spatial coherence of random laser emission.

    Science.gov (United States)

    Redding, Brandon; Choma, Michael A; Cao, Hui

    2011-09-01

    We experimentally studied the spatial coherence of random laser emission from dye solutions containing nanoparticles. The spatial coherence, measured in a double slit experiment, varied significantly with the density of scatterers and the size and shape of the excitation volume. A qualitative explanation is provided, illustrating the dramatic difference from the spatial coherence of a conventional laser. This work demonstrates that random lasers can be controlled to provide intense, spatially incoherent emission for applications in which spatial cross talk or speckle limit performance.

  4. Coherence delay augmented laser beam homogenizer

    Science.gov (United States)

    Rasmussen, P.; Bernhardt, A.

    1993-06-29

    The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.

  5. Coherent states for exactly solvable potentials

    OpenAIRE

    Shreecharan, T.; Panigrahi, Prasanta. K.; Banerji, J.

    2003-01-01

    A general algebraic procedure for constructing coherent states of a wide class of exactly solvable potentials e.g., Morse and P{\\"o}schl-Teller, is given. The method, {\\it a priori}, is potential independent and connects with earlier developed ones, including the oscillator based approaches for coherent states and their generalizations. This approach can be straightforwardly extended to construct more general coherent states for the quantum mechanical potential problems, like the nonlinear co...

  6. Anatomy of a digital coherent receiver

    DEFF Research Database (Denmark)

    Borkowski, Robert; Zibar, Darko; Tafur Monroy, Idelfonso

    2014-01-01

    Digital coherent receivers have gained significant attention in the last decade. The reason for this is that coherent detection, along with digital signal processing (DSP) allows for substantial increase of the channel capacity by employing advanced detection techniques. In this paper, we first......, orthonormaliation, chromatic dispersion compensation/nonlinear compensation, resampling a nd timing recovery, polarization demultiplexing and equalization, frequency and phase recovery, digital demodulation. We also describe novel subsystems of a digital coherent receiver: modulation format recognition...

  7. Neutral current coherent pion production

    CERN Document Server

    Alvarez-Ruso, L; Vacas, M J Vicente

    2007-01-01

    We investigate the neutrino induced coherent pion production reaction at low and intermediate energies. The model includes pion, nucleon and Delta(1232) resonance as the relevant hadronic degrees of freedom. Nuclear medium effects on the production mechanisms and pion distortion are taken into account. We obtain that the dominance of the Delta excitation holds due to large cancellations among the background contributions. We consider two sets of vector and axial-vector N-Delta transition form-factors, evidencing the strong sensitivity of the results to the axial coupling C5A(0). The differences between neutrino and antineutrino cross sections, emerging from interference terms, are also discussed.

  8. Metonymic Mind and Discourse Coherence

    Institute of Scientific and Technical Information of China (English)

    冷晓峰; 范振强

    2007-01-01

    Based on human bodily experience and the interaction with the objective world,a lot of universal schemata are formed in our brain. Also armed with metonymic mind which is based on Gestalt psychology and neural spreading activation,speakers obtain omissions when coding by making semantic leaps. This is done by selecting and coding part of the schema as reference points and let the addressees to infer the whole schemata or the other parts unsaid. This mechanism explains why discourses are coherent at some deeper level.

  9. EEG, alpha waves and coherence

    Science.gov (United States)

    Ascolani, Gianluca

    This thesis addresses some theoretical issues generated by the results of recent analysis of EEG time series proving the brain dynamics are driven by abrupt changes making them depart from the ordinary Poisson condition. These changes are renewal, unpredictable and non-ergodic. We refer to them as crucial events. How is it possible that this form of randomness be compatible with the generation of waves, for instance alpha waves, whose observation seems to suggest the opposite view the brain is characterized by surprisingly extended coherence? To shed light into this apparently irretrievable contradiction we propose a model based on a generalized form of Langevin equation under the influence of a periodic stimulus. We assume that there exist two different forms of time, a subjective form compatible with Poisson statistical physical and an objective form that is accessible to experimental observation. The transition from the former to the latter form is determined by the brain dynamics interpreted as emerging from the cooperative interaction among many units that, in the absence of cooperation would generate Poisson fluctuations. We call natural time the brain internal time and we make the assumption that in the natural time representation the time evolution of the EEG variable y(t) is determined by a Langevin equation perturbed by a periodic process that in this time representation is hardly distinguishable from an erratic process. We show that the representation of this random process in the experimental time scale is characterized by a surprisingly extended coherence. We show that this model generates a sequence of damped oscillations with a time behavior that is remarkably similar to that derived from the analysis of real EEG's. The main result of this research work is that the existence of crucial events is not incompatible with the alpha wave coherence. In addition to this important result, we find another result that may help our group, or any other research

  10. Noise-induced coherent switch

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Taking the famous genetic toggle switch as an example,we numerically investigated the effect of noise on bistability.We found that extrinsic noise resulting from stochastic fluctuations in synthesis and degradation rates and from the environmental fluctuation in gene regulatory processes can induce coherent switch,and that there is an optimal noise intensity such that the noise not only can induce this switch,but also can amplify a weak input signal.In addition,we found that the intrinsic noise introduced through the Poisson τ-leap algorithm cannot induce such a switch.

  11. Dynamic Optical Coherence Tomography Capillaroscopy

    DEFF Research Database (Denmark)

    Ring, Hans Christian; Themstrup, Lotte; Banzhaf, Christina Alette

    2016-01-01

    status, or morphology of the deeper dermal vessels. Dynamic optical coherence tomography (D-OCT) is a recently developed OCT technique that enables detection of high-speed changes in back-scattered light caused by moving cells in vessels. The high resolution of OCT enables the detection of the papillary...... loops. OBJECTIVE To explore the potential for OCT capillaroscopy of the nailfolds using D-OCT. DESIGN, SETTING, AND PARTICIPANTS In this case series study of 4 participants, the nailfolds in 2 patients with systemic sclerosis, 1 patient with dermatomyositis, and a healthy volunteer were scanned using D...

  12. Coherent control near metallic nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Efimov, Ilya [Los Alamos National Laboratory; Efimov, Anatoly [Los Alamos National Laboratory

    2008-01-01

    We study coherent control in the vicinity of metallic nanostructures. Unlike in the case of control in gas or liquid phase, the collective response of electrons in a metallic nanostructure can significantly enhance different frequency components of the control field. This enhancement strongly depends on the geometry of the nanostructure and can substantially modify the temporal profile of the local control field. The changes in the amplitude and phase of the control field near the nanostructure are studied using linear response theory. The inverse problem of finding the external electromagnetic field to generate the desired local control field is considered and solved.

  13. From hybrid swarms to swarms of hybrids

    Science.gov (United States)

    The introgression of modern humans (Homo sapiens) with Neanderthals 40,000 YBP after a half-million years of separation, may have led to the best example of a hybrid swarm on earth. Modern trade and transportation in support of the human hybrids has continued to introduce additional species, genotyp...

  14. The Hybrid Museum: Hybrid Economies of Meaning

    DEFF Research Database (Denmark)

    Vestergaard, Vitus

    2013-01-01

    this article shows that there are two different museum mindsets where the second mindset leans towards participatory practices. It is shown how a museum can support a hybrid economy of meaning that builds on both a user generated economy of meaning and an institutional economy of meaning and adds value to both....... Such a museum is referred to as a hybrid museum....

  15. Hydraulic Hybrid Vehicles

    Science.gov (United States)

    EPA and the United Parcel Service (UPS) have developed a hydraulic hybrid delivery vehicle to explore and demonstrate the environmental benefits of the hydraulic hybrid for urban pick-up and delivery fleets.

  16. Hybrid Management in Hospitals

    DEFF Research Database (Denmark)

    Byrkjeflot, Haldor; Jespersen, Peter Kragh

    2010-01-01

    Artiklen indeholder et litteraturbaseret studium af ledelsesformer i sygehuse, hvor sundhedsfaglig ledelse og generel ledelse mikses til hybride ledelsesformer......Artiklen indeholder et litteraturbaseret studium af ledelsesformer i sygehuse, hvor sundhedsfaglig ledelse og generel ledelse mikses til hybride ledelsesformer...

  17. Coherent detection and digital signal processing for fiber optic communications

    Science.gov (United States)

    Ip, Ezra

    The drive towards higher spectral efficiency in optical fiber systems has generated renewed interest in coherent detection. We review different detection methods, including noncoherent, differentially coherent, and coherent detection, as well as hybrid detection methods. We compare the modulation methods that are enabled and their respective performances in a linear regime. An important system parameter is the number of degrees of freedom (DOF) utilized in transmission. Polarization-multiplexed quadrature-amplitude modulation maximizes spectral efficiency and power efficiency as it uses all four available DOF contained in the two field quadratures in the two polarizations. Dual-polarization homodyne or heterodyne downconversion are linear processes that can fully recover the received signal field in these four DOF. When downconverted signals are sampled at the Nyquist rate, compensation of transmission impairments can be performed using digital signal processing (DSP). Software based receivers benefit from the robustness of DSP, flexibility in design, and ease of adaptation to time-varying channels. Linear impairments, including chromatic dispersion (CD) and polarization-mode dispersion (PMD), can be compensated quasi-exactly using finite impulse response filters. In practical systems, sampling the received signal at 3/2 times the symbol rate is sufficient to enable an arbitrary amount of CD and PMD to be compensated for a sufficiently long equalizer whose tap length scales linearly with transmission distance. Depending on the transmitted constellation and the target bit error rate, the analog-to-digital converter (ADC) should have around 5 to 6 bits of resolution. Digital coherent receivers are naturally suited for the implementation of feedforward carrier recovery, which has superior linewidth tolerance than phase-locked loops, and does not suffer from feedback delay constraints. Differential bit encoding can be used to prevent catastrophic receiver failure due

  18. Coherently combining short data segments for all-sky semi-coherent continuous gravitational wave searches

    CERN Document Server

    Goetz, Evan

    2015-01-01

    We present a method for coherently combining short data segments from gravitational-wave detectors to improve the sensitivity of semi-coherent searches for continuous gravitational waves. All-sky searches for continuous gravitational waves from unknown sources are computationally limited. The semi-coherent approach reduces the computational cost by dividing the entire observation timespan into short segments to be analyzed coherently, then combined together incoherently. Semi-coherent analyses that attempt to improve sensitivity by coherently combining data from multiple detectors face a computational challenge in accounting for uncertainties in signal parameters. In this article, we lay out a technique to meet this challenge using summed Fourier transform coefficients. Applying this technique to one all-sky search algorithm called TwoSpect, we confirm that the sensitivity of all-sky, semi-coherent searches can be improved by coherently combining the short data segments. For misaligned detectors, however, thi...

  19. Coherent spaces, Boolean rings and quantum gates

    Science.gov (United States)

    Vourdas, A.

    2016-10-01

    Coherent spaces spanned by a finite number of coherent states, are introduced. Their coherence properties are studied, using the Dirac contour representation. It is shown that the corresponding projectors resolve the identity, and that they transform into projectors of the same type, under displacement transformations, and also under time evolution. The set of these spaces, with the logical OR and AND operations is a distributive lattice, and with the logical XOR and AND operations is a Boolean ring (Stone's formalism). Applications of this Boolean ring into classical CNOT gates with n-ary variables, and also quantum CNOT gates with coherent states, are discussed.

  20. Quantum oscillators in the canonical coherent states

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, R. de Lima [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Lima, A.F. de; Ferreira, K. de Araujo [Paraiba Univ., Campina Grande, PB (Brazil). Dept. de Fisica; Vaidya, A.N. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Fisica

    2001-11-01

    The main characteristics of the quantum oscillator coherent states including the two-particle Calogero interaction are investigated. We show that these Calogero coherent states are the eigenstates of the second-order differential annihilation operator which is deduced via Wigner-Heisenberg algebraic technique and correspond exactly to the pure uncharged-bosonic states. They posses the important properties of non-orthogonality and completeness. The minimum uncertainty relation for the Wigner oscillator coherent states are investigated. New sets of even and odd coherent states are point out. (author)

  1. Generation of coherence via Gaussian measurements

    Science.gov (United States)

    Albarelli, Francesco; Genoni, Marco G.; Paris, Matteo G. A.

    2017-07-01

    We address measurement-based generation of quantum coherence in continuous variable systems. We consider Gaussian measurements performed on Gaussian states and focus on two scenarios: In the first one, we assume an initially correlated bipartite state shared by two parties and study how correlations may be exploited to remotely create quantum coherence via measurement back action. In particular, we focus on conditional states with zero first moments, so as to address coherence due to properties of the covariance matrix. We consider different classes of bipartite states with incoherent marginals and show that the larger the measurement squeezing, the larger the conditional coherence. Homodyne detection is thus the optimal Gaussian measurement to remotely generate coherence. We also show that for squeezed thermal states there exists a threshold value for the generated coherence which separates entangled and separable states at a fixed energy. Finally, we briefly discuss the tripartite case and the relationship between tripartite correlations and the conditional two-mode coherence. In the second scenario, we address the steady-state coherence of a system interacting with an environment which is continuously monitored. In particular, we discuss the dynamics of an optical parametric oscillator in order to investigate how the coherence of a Gaussian state may be increased by means of time-continuous Gaussian measurement on the interacting environment.

  2. Multi-channel coherent perfect absorbers

    KAUST Repository

    Bai, Ping

    2016-05-18

    The absorption efficiency of a coherent perfect absorber usually depends on the phase coherence of the incident waves on the surfaces. Here, we present a scheme to create a multi-channel coherent perfect absorber in which the constraint of phase coherence is loosened. The scheme has a multi-layer structure such that incident waves in different channels with different angular momenta can be simultaneously and perfectly absorbed. This absorber is robust in achieving high absorption efficiency even if the incident waves become "incoherent" and possess "random" wave fronts. Our work demonstrates a unique approach to designing highly efficient metamaterial absorbers. © CopyrightEPLA, 2016.

  3. Resin Catalyst Hybrids

    Institute of Scientific and Technical Information of China (English)

    S. Asaoka

    2005-01-01

    @@ 1Introduction: What are resin catalyst hybrids? There are typically two types of resin catalyst. One is acidic resin which representative is polystyrene sulfonic acid. The other is basic resin which is availed as metal complex support. The objective items of this study on resin catalyst are consisting of pellet hybrid, equilibrium hybrid and function hybrid of acid and base,as shown in Fig. 1[1-5].

  4. Mesoscale hybrid calibration artifact

    Science.gov (United States)

    Tran, Hy D.; Claudet, Andre A.; Oliver, Andrew D.

    2010-09-07

    A mesoscale calibration artifact, also called a hybrid artifact, suitable for hybrid dimensional measurement and the method for make the artifact. The hybrid artifact has structural characteristics that make it suitable for dimensional measurement in both vision-based systems and touch-probe-based systems. The hybrid artifact employs the intersection of bulk-micromachined planes to fabricate edges that are sharp to the nanometer level and intersecting planes with crystal-lattice-defined angles.

  5. Realizing the Hybrid Library.

    Science.gov (United States)

    Pinfield, Stephen; Eaton, Jonathan; Edwards, Catherine; Russell, Rosemary; Wissenburg, Astrid; Wynne, Peter

    1998-01-01

    Outlines five projects currently funded by the United Kingdom's Electronic Libraries Program (eLib): HyLiFe (Hybrid Library of the Future), MALIBU (MAnaging the hybrid Library for the Benefit of Users), HeadLine (Hybrid Electronic Access and Delivery in the Library Networked Environment), ATHENS (authentication scheme), and BUILDER (Birmingham…

  6. Homoploid hybrid expectations

    Science.gov (United States)

    Homoploid hybrid speciation occurs when a stable, fertile, and reproductively isolated lineage results from hybridization between two distinct species without a change in ploidy level. Reproductive isolation between a homoploid hybrid species and its parents is generally attained via chromosomal re...

  7. Hybrid armature projectile

    Science.gov (United States)

    Hawke, Ronald S.; Asay, James R.; Hall, Clint A.; Konrad, Carl H.; Sauve, Gerald L.; Shahinpoor, Mohsen; Susoeff, Allan R.

    1993-01-01

    A projectile for a railgun that uses a hybrid armature and provides a seed block around part of the outer surface of the projectile to seed the hybrid plasma brush. In addition, the hybrid armature is continuously vaporized to replenish plasma in a plasma armature to provide a tandem armature and provides a unique ridge and groove to reduce plasama blowby.

  8. Intraply Hybrid Composite Design

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1986-01-01

    Several theoretical approaches combined in program. Intraply hybrid composites investigated theoretically and experimentally at Lewis Research Center. Theories developed during investigations and corroborated by attendant experiments used to develop computer program identified as INHYD (Intraply Hybrid Composite Design). INHYD includes several composites micromechanics theories, intraply hybrid composite theories, and integrated hygrothermomechanical theory. Equations from theories used by program as appropriate for user's specific applications.

  9. Hybrid quantum information processing

    Energy Technology Data Exchange (ETDEWEB)

    Furusawa, Akira [Department of Applied Physics, School of Engineering, The University of Tokyo (Japan)

    2014-12-04

    I will briefly explain the definition and advantage of hybrid quantum information processing, which is hybridization of qubit and continuous-variable technologies. The final goal would be realization of universal gate sets both for qubit and continuous-variable quantum information processing with the hybrid technologies. For that purpose, qubit teleportation with a continuousvariable teleporter is one of the most important ingredients.

  10. Wakefields in Coherent Synchrotron Radiation

    Science.gov (United States)

    Billinghurst, Brant E.; Bergstrom, J. C.; Baribeau, C.; Batten, T.; Dallin, L.; May, Tim E.; Vogt, J. M.; Wurtz, Ward A.; Warnock, Robert L.; Bizzozero, D. A.; Kramer, S.; Michaelian, K. H.

    2016-06-01

    When the electron bunches in a storage ring are sufficiently short the electrons act coherently producing radiation several orders of magnitude more intense than normal synchrotron radiation. This is referred to as Coherent Syncrotron Radiation (CSR). Due to the potential of CSR to provide a good source of Terahertz radiation for our users, the Canadian Light Source (CLS) has been researching the production and application of CSR. CSR has been produced at the CLS for many years, and has been used for a number of applications. However, resonances that permeate the spectrum at wavenumber intervals of 0.074 cm-1, and are highly stable under changes in the machine setup, have hampered some experiments. Analogous resonances were predicted long ago in an idealized theory. Through experiments and further calculations we elucidate the resonance and wakefield mechanisms in the CLS vacuum chamber. The wakefield is observed directly in the 30-110 GHz range by rf diodes. These results are consistent with observations made by the interferometer in the THz range. Also discussed will be some practical examples of the application of CSR for the study of condensed phase samples using both transmission and Photoacoustic techniques.

  11. Nucleation pathway in coherent precipitation

    Science.gov (United States)

    Philippe, T.; Blavette, D.

    2011-12-01

    The non-classical nucleation pathway of coherent precipitates has been computed through minimisation of the nucleation barrier in the composition (c)-size (R) space to predict the evolution of nucleus composition. The generalized Gibbs model, developed by Schmelzer et al. [J. Chem. Phys. 112 (2000) p.3820; J. Colloid Interface Sci. 272 (2004) p.109], has been extended to include misfit elastic energy. The composition of critical embryos c* was found to be independent of the interfacial constant. The composition of critical nuclei (c*) decreased with supersaturation. The elastic energy increased both c* and the nucleation barrier, as well as R*. The evolution of nucleus composition (c) as a function of size (R) along the minimum energy pathway was computed. Nucleation only starts when a size threshold is exceeded. Then, rapid enrichment to the expected composition (c β) precedes a constant composition regime. However, for small supersaturations, the change in cluster composition can occur sharply for a very small radius and then the composition slowly increased with a significant change in size. Coherency misfit energy was found to slow down the evolution of nuclei composition with R. The model was compared to experimental results.

  12. The Linac Coherent Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Galayda, John N

    2003-05-21

    A collaboration of scientists from SLAC, UCLA, Los Alamos National Laboratory, Brookhaven National Laboratory, and Argonne National Laboratory have proposed to build the Linac Coherent Light Source (LCLS) facility, a free-electron laser (FEL) on the SLAC site, spanning photon energies 0.8-8 keV. The laser output will be 8-10 GW with pulse lengths 230 fsec or less. The LCLS will offer unprecedented experimental opportunities in the areas of atomic physics, chemical dynamics, plasma physics, nanoscale dynamics, and biomolecular imaging. SLAC has proposed to begin engineering design of the laser in 2003, leading to project completion in 2008. The laser produces x-rays by the self-amplified spontaneous emission (SASE) process: an intense, highly collimated pulse of 14.5 GeV electrons, traveling through a 122 m-long undulator magnet system, is induced by its own synchrotron radiation to form sub-nanometer-scale bunches. The bunching process enhances the coherence and hence the intensity of the emitted synchrotron radiation. The process is analogous to the instability of a high-gain amplifier; the ''noise'' signal that seeds the instability is the shot noise in the electron beam.

  13. Enhanced delegated computing using coherence

    Science.gov (United States)

    Barz, Stefanie; Dunjko, Vedran; Schlederer, Florian; Moore, Merritt; Kashefi, Elham; Walmsley, Ian A.

    2016-03-01

    A longstanding question is whether it is possible to delegate computational tasks securely—such that neither the computation nor the data is revealed to the server. Recently, both a classical and a quantum solution to this problem were found [C. Gentry, in Proceedings of the 41st Annual ACM Symposium on the Theory of Computing (Association for Computing Machinery, New York, 2009), pp. 167-178; A. Broadbent, J. Fitzsimons, and E. Kashefi, in Proceedings of the 50th Annual Symposium on Foundations of Computer Science (IEEE Computer Society, Los Alamitos, CA, 2009), pp. 517-526]. Here, we study the first step towards the interplay between classical and quantum approaches and show how coherence can be used as a tool for secure delegated classical computation. We show that a client with limited computational capacity—restricted to an XOR gate—can perform universal classical computation by manipulating information carriers that may occupy superpositions of two states. Using single photonic qubits or coherent light, we experimentally implement secure delegated classical computations between an independent client and a server, which are installed in two different laboratories and separated by 50 m . The server has access to the light sources and measurement devices, whereas the client may use only a restricted set of passive optical devices to manipulate the information-carrying light beams. Thus, our work highlights how minimal quantum and classical resources can be combined and exploited for classical computing.

  14. Spatial Coherence of Tropical Rainfall

    Science.gov (United States)

    Ratan, Ram; Venugopal, V.; Sukhatme, Jai; Murtugudde, Raghu

    2014-05-01

    We characterise the spatial coherence of tropical rain and its wet spells from observations (TRMM) and assess if models (CMIP5) are able to reproduce the observed features. Based on 15 years (1998-2012) of TRMM 3B42 (V7) 1-degree, daily rainfall, we estimate the spatial decorrelation scale (e-folding distance) of rain at each location in the tropics. A ratio of zonal to meridional spatial scales clearly illustrates that while rain patterns tend to be anisotropic (ratio of 4) over tropical ocean regions (particularly over Pacific ITCZ); over land regions, rain tends to be mostly isotropic. This contrast between ocean and land appears to be reasonably well captured by CMIP5 models, although the anisotropy (ratio) over ocean is much higher than in observations. A very curious behaviour in observations is the presence of a coherent band of spatial decorrelation lengths straddling the equator, in the East Pacific, reminiscent of a double ITCZ that some models tend to simulate. A similar analysis of wet spells of different durations suggests that the decorrelation scale is largely independent of the duration of wet spell.

  15. Coherent states: a contemporary panorama Coherent states: a contemporary panorama

    Science.gov (United States)

    Twareque Ali, S.; Antoine, Jean-Pierre; Bagarello, Fabio; Gazeau, Jean-Pierre

    2012-06-01

    Coherent states (CS) of the harmonic oscillator (also called canonical CS) were introduced in 1926 by Schrödinger in answer to a remark by Lorentz on the classical interpretation of the wave function. They were rediscovered in the early 1960s, first (somewhat implicitly) by Klauder in the context of a novel representation of quantum states, then by Glauber and Sudarshan for the description of coherence in lasers. Since then, CS have grown into an extremely rich domain that pervades almost every corner of physics and have also led to the development of several flourishing topics in mathematics. Along the way, a number of review articles have appeared in the literature, devoted to CS, notably the 1985 reprint volume of Klauder and Skagerstam [1], the 1990 review paper by Zhang et al [2], the 1993 Oak Ridge Conference [3] and the 1995 review paper by Ali et al [4]. Textbooks also have been published, among which one might mention the ground breaking text of Perelomov [5] focusing on the group-theoretical aspects, that of Ali et al [6]1 analyzing systematically the mathematical structure beyond the group-theoretical approach and also the relation to wavelet analysis, that of Dodonov and Man'ko [7] mostly devoted to quantum optics, that of Gazeau [8] more oriented towards the physical, probabilistic and quantization aspects, and finally the very recent one by Combescure and Robert [9]. In retrospect, one can see that the development of CS has gone through a two-phase transition. First, the (simultaneous) discovery in 1972 by Gilmore and Perelomov that CS were rooted in group theory, then the realization that CS can be defined in a purely algebraic way, as an eigenvalue problem or by a series expansion (Malkin and Man'ko 1969, Barut and Girardello 1971, Gazeau and Klauder 1999; references to the original articles may be found in the textbooks quoted above). Both facts resulted in an explosive expansion of the CS literature. We thought, therefore, that the time was ripe

  16. Tracking the coherent generation of polaron pairs in conjugated polymers.

    Science.gov (United States)

    De Sio, Antonietta; Troiani, Filippo; Maiuri, Margherita; Réhault, Julien; Sommer, Ephraim; Lim, James; Huelga, Susana F; Plenio, Martin B; Rozzi, Carlo Andrea; Cerullo, Giulio; Molinari, Elisa; Lienau, Christoph

    2016-12-08

    The optical excitation of organic semiconductors not only generates charge-neutral electron-hole pairs (excitons), but also charge-separated polaron pairs with high yield. The microscopic mechanisms underlying this charge separation have been debated for many years. Here we use ultrafast two-dimensional electronic spectroscopy to study the dynamics of polaron pair formation in a prototypical polymer thin film on a sub-20-fs time scale. We observe multi-period peak oscillations persisting for up to about 1 ps as distinct signatures of vibronic quantum coherence at room temperature. The measured two-dimensional spectra show pronounced peak splittings revealing that the elementary optical excitations of this polymer are hybridized exciton-polaron-pairs, strongly coupled to a dominant underdamped vibrational mode. Coherent vibronic coupling induces ultrafast polaron pair formation, accelerates the charge separation dynamics and makes it insensitive to disorder. These findings open up new perspectives for tailoring light-to-current conversion in organic materials.

  17. The hydrogen hybrid option

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J.R.

    1993-10-15

    The energy efficiency of various piston engine options for series hybrid automobiles are compared with conventional, battery powered electric, and proton exchange membrane (PEM) fuel cell hybrid automobiles. Gasoline, compressed natural gas (CNG), and hydrogen are considered for these hybrids. The engine and fuel comparisons are done on a basis of equal vehicle weight, drag, and rolling resistance. The relative emissions of these various fueled vehicle options are also presented. It is concluded that a highly optimized, hydrogen fueled, piston engine, series electric hybrid automobile will have efficiency comparable to a similar fuel cell hybrid automobile and will have fewer total emissions than the battery powered vehicle, even without a catalyst.

  18. Hybridization and extinction.

    Science.gov (United States)

    Todesco, Marco; Pascual, Mariana A; Owens, Gregory L; Ostevik, Katherine L; Moyers, Brook T; Hübner, Sariel; Heredia, Sylvia M; Hahn, Min A; Caseys, Celine; Bock, Dan G; Rieseberg, Loren H

    2016-08-01

    Hybridization may drive rare taxa to extinction through genetic swamping, where the rare form is replaced by hybrids, or by demographic swamping, where population growth rates are reduced due to the wasteful production of maladaptive hybrids. Conversely, hybridization may rescue the viability of small, inbred populations. Understanding the factors that contribute to destructive versus constructive outcomes of hybridization is key to managing conservation concerns. Here, we survey the literature for studies of hybridization and extinction to identify the ecological, evolutionary, and genetic factors that critically affect extinction risk through hybridization. We find that while extinction risk is highly situation dependent, genetic swamping is much more frequent than demographic swamping. In addition, human involvement is associated with increased risk and high reproductive isolation with reduced risk. Although climate change is predicted to increase the risk of hybridization-induced extinction, we find little empirical support for this prediction. Similarly, theoretical and experimental studies imply that genetic rescue through hybridization may be equally or more probable than demographic swamping, but our literature survey failed to support this claim. We conclude that halting the introduction of hybridization-prone exotics and restoring mature and diverse habitats that are resistant to hybrid establishment should be management priorities.

  19. Spoof Plasmon Hybridization

    CERN Document Server

    Zhang, Jingjing; Luo, Yu; Shen, Xiaopeng; Maier, Stefan A; Cui, Tie Jun

    2016-01-01

    Plasmon hybridization between closely spaced nanoparticles yields new hybrid modes not found in individual constituents, allowing for the engineering of resonance properties and field enhancement capabilities of metallic nanostructure. Experimental verifications of plasmon hybridization have been thus far mostly limited to optical frequencies, as metals cannot support surface plasmons at longer wavelengths. Here, we introduce the concept of 'spoof plasmon hybridization' in highly conductive metal structures and investigate experimentally the interaction of localized surface plasmon resonances (LSPR) in adjacent metal disks corrugated with subwavelength spiral patterns. We show that the hybridization results in the splitting of spoof plasmon modes into bonding and antibonding resonances analogous to molecular orbital rule and plasmonic hybridization in optical spectrum. These hybrid modes can be manipulated to produce enormous field enhancements (larger than 5000) by tuning the separation between disks or alte...

  20. Simultaneous scintillation measurements of coherent and partially coherent beams in an open atmosphere experiment

    Science.gov (United States)

    Efimov, Anatoly; Velizhanin, Kirill; Gelikonov, Grigory

    2014-03-01

    Scintillation indices, probability distribution functions and signal spectra are measured simultaneously for spatially coherent and partially coherent optical beams propagating through various distances in an open atmosphere. The partially coherent beam is produced by coupling the broadband output of a superluminescent diode to a multimode optical fiber. A simple system to adjust the coherence radius by controlling the numerical aperture at the fiber output is implemented. Substantial reduction of the scintillation index and signal fade probability as compared to a slightly diverging coherent Gaussian beam are observed at all propagation distances studied up to 6.5 km.

  1. Extensions and modifications to explanatory coherence

    NARCIS (Netherlands)

    Vreeswijk, G.A.W.

    2016-01-01

    Thagard’s theory of explanatory coherence (TEC) and its implementation ECHO might be considered as the de facto calculus of explanatory coherence. It is an elaborate framework to compare competing scientific theories. Recently, it has become apparent that TEC is also useful as a tool for the

  2. Tight Focusing of Partially Coherent Vortex Beams

    Directory of Open Access Journals (Sweden)

    Rakesh Kumar Singh

    2012-01-01

    Full Text Available Tight focusing of partially polarized vortex beams has been studied. Compact form of the coherence matrix has been derived for polarized vortex beams. Effects of topological charge and polarization distribution of the incident beam on intensity distribution, degree of polarization, and coherence have been investigated.

  3. Quantum Correlation Coefficients for Angular Coherent States

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei; HE Yan; GUO Hao

    2009-01-01

    Quantum covariance and correlation coefficients of angular or SU(2) coherent states are directly calculated for all irreducible unitary representations.These results explicitly verify that the angular coherent states minimize the Robertson-Schrodinger uncertainty relation for all spins, which means that they are the so-called intelligent states.The same results can be obtained by the Schwinger representation approach.

  4. Textual Cohesion and Coherence in Children's Writing.

    Science.gov (United States)

    Fitzgerald, Jill; Spiegel, Dixie Lee

    1986-01-01

    Examined the relationship between cohesion and coherence in children's writing and investigated the degree to which this relationship would vary with quality of writing and grade level. Concludes that the relationship between cohesion and coherence did not vary according to quality of writing or grade level. (SRT)

  5. Coherent acceptability measures in multiperiod models

    NARCIS (Netherlands)

    Roorda, Berend; Schumacher, Hans; Engwerda, Jacob

    2005-01-01

    The framework of coherent risk measures has been introduced by Artzner et al. (1999; Math. Finance 9, 203–228) in a single-period setting. Here, we investigate a similar framework in a multiperiod context. We add an axiom of dynamic consistency to the standard coherence axioms, and obtain a represen

  6. Coherent acceptability measures in multiperiod models

    NARCIS (Netherlands)

    Roorda, Berend; Engwerda, Jacob; Schumacher, Hans

    2004-01-01

    The framework of coherent risk measures has been introduced by Artzner et al. (1999) in a single-period setting. Here we investigate a similar framework in a multiperiod context. We add an axiom of dynamic consistency to the standard coherence axioms, and obtain a representation theorem in terms of

  7. Imaging granulomatous lesions with optical coherence tomography

    DEFF Research Database (Denmark)

    Banzhaf, Christina; Jemec, Gregor B E

    2012-01-01

    To investigate and compare the presentation of granulomatous lesions in optical coherence tomography (OCT) images and compare this to previous studies of nonmelanoma skin tumors.......To investigate and compare the presentation of granulomatous lesions in optical coherence tomography (OCT) images and compare this to previous studies of nonmelanoma skin tumors....

  8. Quantum Processes Which Do Not Use Coherence

    Directory of Open Access Journals (Sweden)

    Benjamin Yadin

    2016-11-01

    Full Text Available A major signature of quantum mechanics beyond classical physics is coherence, the existence of superposition states. The recently developed resource theory of quantum coherence allows the formalization of incoherent operations—those operations which cannot create coherence. We identify the set of operations which additionally do not use coherence. These are such that coherence cannot be exploited by a classical observer, who measures incoherent properties of the system, to go beyond classical dynamics. We give a physical interpretation in terms of interferometry and prove a dilation theorem, showing how these operations can always be constructed by the system interacting, in an incoherent way, with an ancilla. Such a physical justification is not known for the incoherent operations; thus, our results lead to a physically well-motivated resource theory of coherence. Next, we investigate the implications for coherence in multipartite systems. We show that quantum correlations can be defined naturally with respect to a fixed basis, providing a link between coherence and quantum discord. We demonstrate the interplay between these two quantities in the operations that we study and suggest implications for the theory of quantum discord by relating these operations to those which cannot create discord.

  9. Powers of the degree of coherence.

    Science.gov (United States)

    Mei, Zhangrong; Korotkova, Olga; Mao, Yonghua

    2015-04-01

    We establish conditions under which a legitimate degree of coherence of a statistically stationary beam-like field raised to a power results in a novel legitimate degree of coherence. The general results and examples relate to scalar beams having uniform and non-uniform correlations.

  10. Quantum coherence in the dynamical Casimir effect

    Science.gov (United States)

    Samos-Sáenz de Buruaga, D. N.; Sabín, Carlos

    2017-02-01

    We propose to use quantum coherence as the ultimate proof of the quantum nature of the radiation that appears by means of the dynamical Casimir effect in experiments with superconducting microwave waveguides. We show that, unlike previously considered measurements such as entanglement and discord, quantum coherence does not require a threshold value of the external pump amplitude and is highly robust to thermal noise.

  11. Eikonal method for calculation of coherence functions.

    Science.gov (United States)

    Zysk, Adam M; Carney, P Scott; Schotland, John C

    2005-07-22

    A method is presented for computing the cross-spectral density of a special class of partially coherent fields in which the coherent modes obey an eikonal equation. This method allows for statistical analysis of optical systems based on simple ray tracing.

  12. Application of coherent 10 micron imaging lidar

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, M.L.; Hutchinson, D.P.; Richards, R.K.; Bennett, C.A.

    1997-04-01

    With the continuing progress in mid-IR array detector technology and high bandwidth fan-outs, i.f. electronics, high speed digitizers, and processing capability, true coherent imaging lidar is becoming a reality. In this paper experimental results are described using a 10 micron coherent imaging lidar.

  13. Ways of development of compact coherent femtosecond X-ray sources for applications in nano- and biophotonics

    Science.gov (United States)

    Mikheev, L.

    2017-01-01

    Ways of the development of compact coherent sources of soft X-ray femtosecond pulses are discussed, which meet the requirements for the implementation of the “diffraction-before-destruction” approach in the lensless X-ray Coherent Diffractive Imaging (CDI) technique enabling quantitative 3D mapping of material structure with the nanoscale spatial resolution. An innovative hybrid (solid/gas) approach to produce ultra-intense femtosecond laser pulses in the visible is described in the context of its applications for laser driven high harmonic generation (HHG) and soft X-ray generation in laser plasmas due to recombination mechanism of excitation.

  14. Marine Fish Hybridization

    KAUST Repository

    He, Song

    2017-04-01

    Natural hybridization is reproduction (without artificial influence) between two or more species/populations which are distinguishable from each other by heritable characters. Natural hybridizations among marine fishes were highly underappreciated due to limited research effort; it seems that this phenomenon occurs more often than is commonly recognized. As hybridization plays an important role in biodiversity processes in the marine environment, detecting hybridization events and investigating hybridization is important to understand and protect biodiversity. The first chapter sets the framework for this disseration study. The Cohesion Species Concept was selected as the working definition of a species for this study as it can handle marine fish hybridization events. The concept does not require restrictive species boundaries. A general history and background of natural hybridization in marine fishes is reviewed during in chapter as well. Four marine fish hybridization cases were examed and documented in Chapters 2 to 5. In each case study, at least one diagnostic nuclear marker, screened from among ~14 candidate markers, was found to discriminate the putative hybridizing parent species. To further investigate genetic evidence to support the hybrid status for each hybrid offspring in each case, haploweb analysis on diagnostic markers (nuclear and/or mitochondrial) and the DAPC/PCA analysis on microsatellite data were used. By combining the genetic evidences, morphological traits, and ecological observations together, the potential reasons that triggered each hybridization events and the potential genetic/ecology effects could be discussed. In the last chapter, sequences from 82 pairs of hybridizing parents species (for which COI barcoding sequences were available either on GenBank or in our lab) were collected. By comparing the COI fragment p-distance between each hybridizing parent species, some general questions about marine fish hybridization were discussed: Is

  15. The extraction of work from quantum coherence

    Science.gov (United States)

    Korzekwa, Kamil; Lostaglio, Matteo; Oppenheim, Jonathan; Jennings, David

    2016-02-01

    The interplay between quantum-mechanical properties, such as coherence, and classical notions, such as energy, is a subtle topic at the forefront of quantum thermodynamics. The traditional Carnot argument limits the conversion of heat to work; here we critically assess the problem of converting coherence to work. Through a careful account of all resources involved in the thermodynamic transformations within a fully quantum-mechanical treatment, we show that there exist thermal machines extracting work from coherence arbitrarily well. Such machines only need to act on individual copies of a state and can be reused. On the other hand, we show that for any thermal machine with finite resources not all the coherence of a state can be extracted as work. However, even bounded thermal machines can be reused infinitely many times in the process of work extraction from coherence.

  16. Coherent control of photoelectron wavepacket angular interferograms

    Science.gov (United States)

    Hockett, P.; Wollenhaupt, M.; Baumert, T.

    2015-11-01

    Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process, where the final (time-integrated) observable coherently samples all instantaneous states of the light-matter interaction. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the coherent control over the resultant photoelectron interferogram is thus explored in detail. Based on this understanding, the use of coherent control with polarization-shaped pulses as a methodology for a highly multiplexed coherent quantum metrology is also investigated, and defined in terms of the information content of the observable.

  17. High power coherent polarization locked laser diode.

    Science.gov (United States)

    Purnawirman; Phua, P B

    2011-03-14

    We have coherently combined a broad area laser diode array to obtain high power single-lobed output by using coherent polarization locking. The single-lobed coherent beam is achieved by spatially combining four diode emitters using walk-off crystals and waveplates while their phases are passively locked via polarization discrimination. While our previous work focused on coherent polarization locking of diode in Gaussian beams, we demonstrate in this paper, the feasibility of the same polarization discrimination for locking multimode beams from broad area diode lasers. The resonator is designed to mitigate the loss from smile effect by using retro-reflection feedback in the cavity. In a 980 nm diode array, we produced 7.2 W coherent output with M2 of 1.5x11.5. The brightness of the diode is improved by more than an order of magnitude.

  18. Optical coherence tomography in dermatology

    Science.gov (United States)

    Sattler, Elke; Kästle, Raphaela; Welzel, Julia

    2013-06-01

    Optical coherence tomography (OCT) is a noninvasive diagnostic method that offers a view into the superficial layers of the skin in vivo in real-time. An infrared broadband light source allows the investigation of skin architecture and changes up to a depth of 1 to 2 mm with a resolution between 15 and 3 μm, depending on the system used. Thus OCT enables evaluation of skin lesions, especially nonmelanoma skin cancers and inflammatory diseases, quantification of skin changes, visualization of parasitic infestations, and examination of other indications such as the investigation of nails. OCT provides a quick and useful diagnostic imaging technique for a number of clinical questions and is a valuable addition or complement to other noninvasive imaging tools such as dermoscopy, high-frequency ultrasound, and confocal laser scan microscopy.

  19. On Attracting Lagrangian Coherent Structures

    CERN Document Server

    Karrasch, Daniel

    2013-01-01

    In this note, we show that in the autonomous, two-dimensional incompressible saddle flow, contrary to common intuition, also attracting Lagrangian Coherent Structures (LCSs) can show up as ridges of the forward finite-time Lyapunov exponent (FTLE) field. This raises the issue of characterization of attracting LCSs from forward time FTLE analysis. First, we extend recent results of Haller & Sapsis (2011) [11] on the relation between forward and backward maximal and minimal stretching rates to the whole finite-time Lyapunov spectrum and to stretching directions by considering the singular value decomposition (SVD) of the deformation gradient. We show two significant advantages of the SVD compared to the usual eigendecomposition of the Cauchy-Green strain tensor: (1) one gains theoretical insight into local deformation under a finite-time dynamical system, and (2) one obtains both complete forward and backward strain information from a single grid advection. Furthermore, we give a short and direct proof of t...

  20. GPU-Powered Coherent Beamforming

    CERN Document Server

    Magro, Alessio; Hickish, Jack

    2014-01-01

    GPU-based beamforming is a relatively unexplored area in radio astronomy, possibly due to the assumption that any such system will be severely limited by the PCIe bandwidth required to transfer data to the GPU. We have developed a CUDA-based GPU implementation of a coherent beamformer, specifically designed and optimised for deployment at the BEST-2 array which can generate an arbitrary number of synthesized beams for a wide range of parameters. It achieves $\\sim$1.3 TFLOPs on an NVIDIA Tesla K20, approximately 10x faster than an optimised, multithreaded CPU implementation. This kernel has been integrated into two real-time, GPU-based time-domain software pipelines deployed at the BEST-2 array in Medicina: a standalone beamforming pipeline and a transient detection pipeline. We present performance benchmarks for the beamforming kernel as well as the transient detection pipeline with beamforming capabilities as well as results of test observation.

  1. Nuclear structure with coherent states

    CERN Document Server

    Raduta, Apolodor Aristotel

    2015-01-01

    This book covers the essential features of a large variety of nuclear structure properties, both collective and microscopic in nature. Most of results are given in an analytical form thus giving deep insight into the relevant phenomena. Using coherent states as variational states, which allows a description in the classical phase space, or provides the generating function for a boson basis, is an efficient tool to account, in a realistic fashion, for many complex properties. A detailed comparison with all existing nuclear structure models provides readers with a proper framework and, at the same time, demonstrates the prospects for new developments. The topics addressed are very much of current concern in the field. The book will appeal to practicing researchers and, due to its self-contained account, can also be successfully read and used by new graduate students.

  2. Tachyonic Dispersion in Coherent Networks

    CERN Document Server

    Chong, Y D

    2015-01-01

    We propose a technique to realize a tachyonic band structure in a coherent network, such as an array of coupled ring resonators. This is achieved by adding "PT symmetric" spatially-balanced gain and loss to each node of the network. In a square-lattice network, the quasi-energy bandstructure exhibits a tachyonic dispersion relation, centered at either the center or corner of the Brillouin zone. There is one tachyonic hyperboloid in each gap, unlike in PT-symmetric tight-binding honeycomb lattices where the hyperboloids occur in pairs. The dispersion relation can be probed by measuring the peaks in transmission across a finite network as the gain/loss parameter is varied.

  3. Coherent magnetic semiconductor nanodot arrays

    Directory of Open Access Journals (Sweden)

    Xiu Faxian

    2011-01-01

    Full Text Available Abstract In searching appropriate candidates of magnetic semiconductors compatible with mainstream Si technology for future spintronic devices, extensive attention has been focused on Mn-doped Ge magnetic semiconductors. Up to now, lack of reliable methods to obtain high-quality MnGe nanostructures with a desired shape and a good controllability has been a barrier to make these materials practically applicable for spintronic devices. Here, we report, for the first time, an innovative growth approach to produce self-assembled and coherent magnetic MnGe nanodot arrays with an excellent reproducibility. Magnetotransport experiments reveal that the nanodot arrays possess giant magneto-resistance associated with geometrical effects. The discovery of the MnGe nanodot arrays paves the way towards next-generation high-density magnetic memories and spintronic devices with low-power dissipation.

  4. Optical Coherence Tomography: Advanced Modeling

    DEFF Research Database (Denmark)

    Andersen, Peter E.; Thrane, Lars; Yura, Harold T.;

    2013-01-01

    Analytical and numerical models for describing and understanding the light propagation in samples imaged by optical coherence tomography (OCT) systems are presented. An analytical model for calculating the OCT signal based on the extended Huygens-Fresnel principle valid both for the single......- and multiple-scattering regimes is derived. An advanced Monte Carlo model for calculating the OCT signal is also derived, and the validity of this model is shown through a mathematical proof based on the extended Huygens-Fresnel principle. From the analytical model, an algorithm for enhancing OCT images...... is developed, the so-called true-reflection algorithm in which the OCT signal may be corrected for the attenuation caused by scattering. The algorithm is verified experimentally and by using the Monte Carlo model as a numerical tissue phantom. Applications of extraction of optical properties from tissue...

  5. Evaluation of a cheap ultrasonic stage for light source coherence function measurement, optical coherence tomography, optical coherence microscopy, and dynamic focusing

    NARCIS (Netherlands)

    Krstajic, Nikola; Matcher, Stephen J.; Childs, David; Hogg, Richard; Smallwood, Rod; Steenbergen, Wiendelt; Andersen, Peter E.; Bouma, Brett E.

    2009-01-01

    We evaluate the performance of a cheap ultrasonic stage in setups related to optical coherence tomography. The stage was used in several configurations: 1) optical delay line in optical coherence tomography (OCT) setup; 2) as a delay line measuring coherence function of a low coherence source (e.g.

  6. Continuous-wave anti-Stokes Raman laser based on phase-matched nondegenerate four-wave mixing.

    Science.gov (United States)

    Zaitsu, Shin-ichi; Imasaka, Totaro

    2015-01-01

    We demonstrate phase-matched nondegenerate four-wave mixing (FWM) in a high-finesse optical cavity using a gaseous Raman-active medium pumped by two independent continuous-wave lasers. Efficient upconversion is achieved for pump beams at different wavelengths under phase-matched conditions by optimizing the total dispersion of the hydrogen-filled optical cavity. The independent control of the pump-beam polarizations leads to further enhancement of the upconversion efficiency arising from a larger Raman gain than that in degenerate FWM. This approach offers a promising alternative for a narrow-linewidth tunable light source for highly precise laser spectroscopy.

  7. Investigations of Crossed Andreev Reflection in Hybrid Superconductor-Ferromagnet Structures

    Science.gov (United States)

    Colci O'Hara, Madalina

    2009-01-01

    Cooper pair splitting is predicted to occur in hybrid devices where a superconductor is coupled to two ferromagnetic wires placed at a distance less than the superconducting coherence length. This thesis searches for signatures of this process, called crossed Andreev reflection (CAR), in three device geometries. The first devices studied are…

  8. Exciton dynamics and non-linearities in two-dimensional hybrid organic perovskites

    Science.gov (United States)

    Abdel-Baki, K.; Boitier, F.; Diab, H.; Lanty, G.; Jemli, K.; Lédée, F.; Garrot, D.; Deleporte, E.; Lauret, J. S.

    2016-02-01

    Due to their high potentiality for photovoltaic applications or coherent light sources, a renewed interest in hybrid organic perovskites has emerged for few years. When they are arranged in two dimensions, these materials can be considered as hybrid quantum wells. One consequence of the unique structure of 2D hybrid organic perovskites is a huge exciton binding energy that can be tailored through chemical engineering. We present experimental investigations of the exciton non-linearities by means of femtosecond pump-probe spectroscopy. The exciton dynamics is fitted with a bi-exponential decay with a free exciton life-time of ˜100 ps. Moreover, an ultrafast intraband relaxation (energy.

  9. Henkin and Hybrid Logic

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Huertas, Antonia; Manzano, Maria;

    2014-01-01

    Leon Henkin was not a modal logician, but there is a branch of modal logic that has been deeply influenced by his work. That branch is hybrid logic, a family of logics that extend orthodox modal logic with special proposition symbols (called nominals) that name worlds. This paper explains why...... Henkin’s techniques are so important in hybrid logic. We do so by proving a completeness result for a hybrid type theory called HTT, probably the strongest hybrid logic that has yet been explored. Our completeness result builds on earlier work with a system called BHTT, or basic hybrid type theory...... is due to the first-order perspective, which lies at the heart of Henin’s best known work and hybrid logic....

  10. Long-lived coherence in carotenoids

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J A; Cannon, E; Van Dao, L; Hannaford, P [ARC Centre of Excellence for Coherent X-ray Science, Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Victoria 3122 (Australia); Quiney, H M; Nugent, K A, E-mail: jdavis@swin.edu.a [ARC Centre of Excellence for Coherent X-ray Science, School of Physics, University of Melbourne, Victoria 3010 (Australia)

    2010-08-15

    We use two-colour vibronic coherence spectroscopy to observe long-lived vibrational coherences in the ground electronic state of carotenoid molecules, with decoherence times in excess of 1 ps. Lycopene and spheroidene were studied isolated in solution, and within the LH2 light-harvesting complex extracted from purple bacteria. The vibrational coherence time is shown to increase significantly for the carotenoid in the complex, providing further support to previous assertions that long-lived electronic coherences in light-harvesting complexes are facilitated by in-phase motion of the chromophores and surrounding proteins. Using this technique, we are also able to follow the evolution of excited state coherences and find that for carotenoids in the light-harvesting complex the (S{sub 2}|S{sub 0}) superposition remains coherent for more than 70 fs. In addition to the implications of this long electronic decoherence time, the extended coherence allows us to observe the evolution of the excited state wavepacket. These experiments reveal an enhancement of the vibronic coupling to the first vibrational level of the C-C stretching mode and/or methyl-rocking mode in the ground electronic state 70 fs after the initial excitation. These observations open the door to future experiments and modelling that may be able to resolve the relaxation dynamics of carotenoids in solution and in natural light-harvesting systems.

  11. Coherence and correspondence in engineering design

    Directory of Open Access Journals (Sweden)

    Konstantinos V. Katsikopoulos

    2009-03-01

    Full Text Available I show how the coherence/correspondence distinction can inform the conversation about decision methods for engineering design. Some engineers argue for the application of multi-attribute utility theory while others argue for what they call heuristics. To clarify the differences among methods, I first ask whether each method aims at achieving coherence or correspondence. By analyzing statements in the design literature, I argue that utility theory aims at achieving coherence and heuristics aim at achieving correspondence. Second, I ask if achieving coherence always implies achieving correspondence. It is important to provide an answer because while in design the objective is correspondence, it is difficult to assess it, and coherence that is easier to assess is used as a surrogate. I argue that coherence does not always imply correspondence in design and that this is also the case in problems studied in judgment and decision-making research. Uncovering the conditions under which coherence implies, or does not imply, correspondence is a topic where engineering design and judgment and decision-making research might connect.

  12. Coherence in X-ray physics.

    Science.gov (United States)

    Lengeler, B

    2001-06-01

    Highly brilliant synchrotron radiation sources have opened up the possibility of using coherent X-rays in spectroscopy and imaging. Coherent X-rays are characterized by a large lateral coherence length. Speckle spectroscopy is extended to hard X-rays, improving the resolution to the nm range. It has become possible to image opaque objects in phase contrast with a sensitivity far superior to imaging in absorption contrast. All the currently available X-ray sources are chaotic sources. Their characterization in terms of coherence functions of the first and second order is introduced. The concept of coherence volume, defined in quantum optics terms, is generalized for scattering experiments. When the illuminated sample volume is smaller than the coherence volume, the individuality of the defect arrangement in a sample shows up as speckle in the scattered intensity. Otherwise, a configurational average washes out the speckle and only diffuse scattering and possibly Bragg reflections will survive. The loss of interference due to the finite detection time, to the finite detector pixel size and to uncontrolled degrees of freedom in the sample is discussed at length. A comparison between X-ray scattering, neutron scattering and mesoscopic electron transport is given. A few examples illustrate the possibilities of coherent X-rays for imaging and intensity correlation spectroscopy.

  13. Photosynthetic light harvesting: excitons and coherence.

    Science.gov (United States)

    Fassioli, Francesca; Dinshaw, Rayomond; Arpin, Paul C; Scholes, Gregory D

    2014-03-06

    Photosynthesis begins with light harvesting, where specialized pigment-protein complexes transform sunlight into electronic excitations delivered to reaction centres to initiate charge separation. There is evidence that quantum coherence between electronic excited states plays a role in energy transfer. In this review, we discuss how quantum coherence manifests in photosynthetic light harvesting and its implications. We begin by examining the concept of an exciton, an excited electronic state delocalized over several spatially separated molecules, which is the most widely available signature of quantum coherence in light harvesting. We then discuss recent results concerning the possibility that quantum coherence between electronically excited states of donors and acceptors may give rise to a quantum coherent evolution of excitations, modifying the traditional incoherent picture of energy transfer. Key to this (partially) coherent energy transfer appears to be the structure of the environment, in particular the participation of non-equilibrium vibrational modes. We discuss the open questions and controversies regarding quantum coherent energy transfer and how these can be addressed using new experimental techniques.

  14. Long-lived coherence in carotenoids

    Science.gov (United States)

    Davis, J. A.; Cannon, E.; Van Dao, L.; Hannaford, P.; Quiney, H. M.; Nugent, K. A.

    2010-08-01

    We use two-colour vibronic coherence spectroscopy to observe long-lived vibrational coherences in the ground electronic state of carotenoid molecules, with decoherence times in excess of 1 ps. Lycopene and spheroidene were studied isolated in solution, and within the LH2 light-harvesting complex extracted from purple bacteria. The vibrational coherence time is shown to increase significantly for the carotenoid in the complex, providing further support to previous assertions that long-lived electronic coherences in light-harvesting complexes are facilitated by in-phase motion of the chromophores and surrounding proteins. Using this technique, we are also able to follow the evolution of excited state coherences and find that for carotenoids in the light-harvesting complex the langS2|S0rang superposition remains coherent for more than 70 fs. In addition to the implications of this long electronic decoherence time, the extended coherence allows us to observe the evolution of the excited state wavepacket. These experiments reveal an enhancement of the vibronic coupling to the first vibrational level of the C-C stretching mode and/or methyl-rocking mode in the ground electronic state 70 fs after the initial excitation. These observations open the door to future experiments and modelling that may be able to resolve the relaxation dynamics of carotenoids in solution and in natural light-harvesting systems.

  15. Can two partially coherent cosh-Gaussian beams generate far fields with the same spectral degree of coherence?

    Institute of Scientific and Technical Information of China (English)

    Lü Su-Ye; Lü Bai-Da

    2009-01-01

    Taking partially coherent cosh-Gaussian (ChG) beams as an example of more general partially coherent beams,we have studied the spectral degree of coherence of partially coherent ChG beams in the far field. It is shown that,unlike Gaussian Schell-model (GSM) beams,in the strict sense there do not exist two partially coherent ChG beams which can generate far fields with the same spectral degree of coherence. However,under certain conditions it is possible to find two partially coherent ChG beams with the same spectral degree of coherence in the far field.

  16. Hybrid Photonic Integration on a Polymer Platform

    Directory of Open Access Journals (Sweden)

    Ziyang Zhang

    2015-09-01

    Full Text Available To fulfill the functionality demands from the fast developing optical networks, a hybrid integration approach allows for combining the advantages of various material platforms. We have established a polymer-based hybrid integration platform (polyboard, which provides flexible optical input/ouptut interfaces (I/Os that allow robust coupling of indium phosphide (InP-based active components, passive insertion of thin-film-based optical elements, and on-chip attachment of optical fibers. This work reviews the recent progress of our polyboard platform. On the fundamental level, multi-core waveguides and polymer/silicon nitride heterogeneous waveguides have been fabricated, broadening device design possibilities and enabling 3D photonic integration. Furthermore, 40-channel optical line terminals and compact, bi-directional optical network units have been developed as highly functional, low-cost devices for the wavelength division multiplexed passive optical network. On a larger scale, thermo-optic elements, thin-film elements and an InP gain chip have been integrated on the polyboard to realize a colorless, dual-polarization optical 90° hybrid as the frontend of a coherent receiver. For high-end applications, a wavelength tunable 100Gbaud transmitter module has been demonstrated, manifesting the joint contribution from the polyboard technology, high speed polymer electro-optic modulator, InP driver electronics and ceramic electronic interconnects.

  17. BSA Hybrid Synthesized Polymer

    Institute of Scientific and Technical Information of China (English)

    Zong Bin LIU; Xiao Pei DENG; Chang Sheng ZHAO

    2006-01-01

    Bovine serum albumin (BSA), a naturally occurring biopolymer, was regarded as a polymeric material to graft to an acrylic acid (AA)-N-vinyl pyrrolidone (NVP) copolymer to form a biomacromolecular hybrid polymer. The hybrid polymer can be blended with polyethersulfone (PES) to increase the hydrophilicity of the PES membrane, which suggested that the hybrid polymer might have a wide application in the modification of biomaterials.

  18. Hybrid Action Systems

    DEFF Research Database (Denmark)

    Ronkko, Mauno; Ravn, Anders P.

    1997-01-01

    a differential action, which allows differential equations as primitive actions. The extension allows us to model hybrid systems with both continuous and discrete behaviour. The main result of this paper is an extension of such a hybrid action system with parallel composition. The extension does not change...... the original meaning of the parallel composition, and therefore also the ordinary action systems can be composed in parallel with the hybrid action systems....

  19. HYBRID VEHICLE CONTROL SYSTEM

    Directory of Open Access Journals (Sweden)

    V. Dvadnenko

    2016-06-01

    Full Text Available The hybrid vehicle control system includes a start–stop system for an internal combustion engine. The system works in a hybrid mode and normal vehicle operation. To simplify the start–stop system, there were user new possibilities of a hybrid car, which appeared after the conversion. Results of the circuit design of the proposed system of basic blocks are analyzed.

  20. Nanoscale Organic Hybrid Electrolytes

    KAUST Repository

    Nugent, Jennifer L.

    2010-08-20

    Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Hybrid radiator cooling system

    Science.gov (United States)

    France, David M.; Smith, David S.; Yu, Wenhua; Routbort, Jules L.

    2016-03-15

    A method and hybrid radiator-cooling apparatus for implementing enhanced radiator-cooling are provided. The hybrid radiator-cooling apparatus includes an air-side finned surface for air cooling; an elongated vertically extending surface extending outwardly from the air-side finned surface on a downstream air-side of the hybrid radiator; and a water supply for selectively providing evaporative cooling with water flow by gravity on the elongated vertically extending surface.

  2. Damage Proxy Map from Interferometric Synthetic Aperture Radar Coherence

    Science.gov (United States)

    Yun, Sang-Ho (Inventor); Fielding, Eric Jameson (Inventor); Webb, Frank H. (Inventor); Simons, Mark (Inventor)

    2015-01-01

    A method, apparatus, and article of manufacture provide the ability to generate a damage proxy map. A master coherence map and a slave coherence map, for an area prior and subsequent to (including) a damage event are obtained. The slave coherence map is registered to the master coherence map. Pixel values of the slave coherence map are modified using histogram matching to provide a first histogram of the master coherence map that exactly matches a second histogram of the slave coherence map. A coherence difference between the slave coherence map and the master coherence map is computed to produce a damage proxy map. The damage proxy map is displayed with the coherence difference displayed in a visually distinguishable manner.

  3. NASA's Earth Data Coherent Web

    Science.gov (United States)

    Gonzalez, R.; Murphy, K. J.; Cechini, M. F.

    2011-12-01

    NASA Earth Science Data Systems are a large and continuing investment in science data management activities. The Earth Science Data and Information System (ESDIS) project manages the science systems of the Earth Observing System Data and Information System (EOSDIS). EOSDIS provides science data to a wide community of users. Websites are the front door to data and services for users (science, programmatic, missions, citizen scientist, etc...), but these are disparate and disharmonious. Earth science is interdisciplinary thus, EOSDIS must enable users to discover and use the information, data and services they need in an easy and coherent manner. Users should be able to interact with each EOSDIS element in a predictable way and see EOSDIS as a program of inter-related but distinct systems each with expertise in a different science and/or information technology domain. Additionally, users should be presented with a general search capability that can be customized for each research discipline. Furthermore, the array of domain specific expertise along with crosscutting capabilities should be harmonized so users are presented with a common language and information framework to efficiently perform science investigations. The Earthdata Coherent Web Project goals are (1) to present NASA's EOSDIS as a coherent yet transparent system of systems that provide a highly functioning, integrated web presence that ties together information content and web services throughout EOSDIS so science users can easily find, access, and use data collected by NASA's Earth science missions. (2) Fresh, engaging and continually updated and coordinated content. (3) Create an active and immersive science user experience leveraging Web Services (e.g. W*S, SOAP, RESTful) from remote and local data centers and projects to reduce barriers to using EOSDIS data. Goals will be reached through a phased approach where functionality and processes are incrementally added. Phase I focused on the following main

  4. Coherence in Turbulence: New Perspective

    Science.gov (United States)

    Levich, Eugene

    2009-07-01

    It is claimed that turbulence in fluids is inherently coherent phenomenon. The coherence shows up clearly as strongly correlated helicity fluctuations of opposite sign. The helicity fluctuations have cellular structure forming clusters that are actually observed as vorticity bands and coherent structures in laboratory turbulence, direct numerical simulations and most obviously in atmospheric turbulence. The clusters are named BCC - Beltrami Cellular Clusters - because of the observed nearly total alignment of the velocity and vorticity fields in each particular cell, and hence nearly maximal possible helicity in each cell; although when averaged over all the cells the residual mean helicity in general is small and does not play active dynamical role. The Beltrami like fluctuations are short-lived and stabilize only in small and generally contiguous sub-domains that are tending to a (multi)fractal in the asymptotic limit of large Reynolds numbers, Re → ∞. For the model of homogeneous isotropic turbulence the theory predicts the leading fractal dimension of BCC to be: DF = 2.5. This particular BCC is responsible for generating the Kolmogorov -5/3 power law energy spectrum. The most obvious role that BCC play dynamically is that the nonlinear interactions in them are relatively reduced, due to strong spatial alignment between the velocity field v(r, t) and the vorticity field ω(r, t) = curlv(r, t), while the physical quantities typically best characterizing turbulence intermittency, such as entrophy, vorticity stretching and generation, and energy dissipation are maximized in and near them. The theory quantitatively relates the reduction of nonlinear inter-actions to the BCC fractal dimension DF and subsequent turbulence intermittency. It is further asserted that BCC is a fundamental feature of all turbulent flows, e.g., wall bounded turbulent flows, atmospheric and oceanic flows, and their leading fractal dimension remains invariant and universal in these flows

  5. Hybrid Unifying Variable Supernetwork Model

    Institute of Scientific and Technical Information of China (English)

    LIU; Qiang; FANG; Jin-qing; LI; Yong

    2015-01-01

    In order to compare new phenomenon of topology change,evolution,hybrid ratio and network characteristics of unified hybrid network theoretical model with unified hybrid supernetwork model,this paper constructed unified hybrid variable supernetwork model(HUVSM).The first layer introduces a hybrid ratio dr,the

  6. Large Unifying Hybrid Supernetwork Model

    Institute of Scientific and Technical Information of China (English)

    LIU; Qiang; FANG; Jin-qing; LI; Yong

    2015-01-01

    For depicting multi-hybrid process,large unifying hybrid network model(so called LUHNM)has two sub-hybrid ratios except dr.They are deterministic hybrid ratio(so called fd)and random hybrid ratio(so called gr),respectively.

  7. Experimental study on partial coherence source

    CERN Document Server

    Zhao Xue Qing; Yuan Xiao; LiuJingRu; Wang Long Hua; Tang Ying; Huang, Kerson

    2002-01-01

    Partial coherence source is a key part in the laser system using echelon-free introduced spatial incoherence beam smoothing technique. Different kinds of partial coherence sources have been studied experimentally for improving the uniformity of laser intensity distribution. It is found that the source produced by excimer laser scattering on the surface of a teflon plate is ideal. The properties of this kind of source are studied. As a result, the uniformity of source beam intensity distribution, the beam spatial coherence and energy transfer efficiency of the source are obtained

  8. Relations between Coherence and Path Information.

    Science.gov (United States)

    Bagan, Emilio; Bergou, János A; Cottrell, Seth S; Hillery, Mark

    2016-04-22

    We find two relations between coherence and path information in a multipath interferometer. The first builds on earlier results for the two-path interferometer, which used minimum-error state discrimination between detector states to provide the path information. For visibility, which was used in the two-path case, we substitute a recently defined l_{1} measure of quantum coherence. The second is an entropic relation in which the path information is characterized by the mutual information between the detector states and the outcome of the measurement performed on them, and the coherence measure is one based on relative entropy.

  9. Coherent oscillations of driven rf SQUID metamaterials.

    Science.gov (United States)

    Trepanier, Melissa; Zhang, Daimeng; Mukhanov, Oleg; Koshelets, V P; Jung, Philipp; Butz, Susanne; Ott, Edward; Antonsen, Thomas M; Ustinov, Alexey V; Anlage, Steven M

    2017-05-01

    Through experiments and numerical simulations we explore the behavior of rf SQUID (radio frequency superconducting quantum interference device) metamaterials, which show extreme tunability and nonlinearity. The emergent electromagnetic properties of this metamaterial are sensitive to the degree of coherent response of the driven interacting SQUIDs. Coherence suffers in the presence of disorder, which is experimentally found to be mainly due to a dc flux gradient. We demonstrate methods to recover the coherence, specifically by varying the coupling between the SQUID meta-atoms and increasing the temperature or the amplitude of the applied rf flux.

  10. Spatial coherence of random laser emission

    CERN Document Server

    Redding, Brandon; Cao, Hui

    2011-01-01

    We experimentally studied the spatial coherence of random laser emission from dye solutions containing nanoparticles. The spatial coherence, measured in a double-slit experiment, varied significantly with the density of scatterers and the size and shape of the excitation volume. A qualitative explanation is provided, illustrating the dramatic difference from the spatial coherence of a conventional laser. This work demonstrates that random lasers can be controlled to provide intense, spatially incoherent emission for applications in which spatial cross talk or speckle limit performance.

  11. Adiabatic Quantum Computation: Coherent Control Back Action

    Science.gov (United States)

    Goswami, Debabrata

    2013-01-01

    Though attractive from scalability aspects, optical approaches to quantum computing are highly prone to decoherence and rapid population loss due to nonradiative processes such as vibrational redistribution. We show that such effects can be reduced by adiabatic coherent control, in which quantum interference between multiple excitation pathways is used to cancel coupling to the unwanted, non-radiative channels. We focus on experimentally demonstrated adiabatic controlled population transfer experiments wherein the details on the coherence aspects are yet to be explored theoretically but are important for quantum computation. Such quantum computing schemes also form a back-action connection to coherent control developments. PMID:23788822

  12. Coherent absorption of N00N states

    CERN Document Server

    Roger, Thomas; Lyons, Ashley; Giovannini, Daniel; Romero, Jacquiline; Jeffers, John; Padgett, Miles; Faccio, Daniele

    2016-01-01

    Recent results in deeply subwavelength thickness films demonstrated coherent control and logical gate operations with both classical and single photon light sources. However, quantum processing and devices typically involve more than one photon and non-trivial input quantum states. Here we experimentally investigate two-photon N00N state coherent absorption in a multilayer graphene film. Depending on the N00N state input phase, it is possible to selectively choose between single or two photon absorption of the input state in the graphene film. These results demonstrate that coherent absorption in the quantum regime exhibits unique features opening up applications in multiphoton spectroscopy and imaging.

  13. Coherence properties of Kerr frequency combs

    CERN Document Server

    Erkintalo, Miro

    2014-01-01

    We use numerical simulations based on an extended Lugiato-Lefever equation (LLE) to investigate the stability properties of Kerr frequency combs generated in microresonators. In particular, we show that an ensemble average calculated over sequences of output fields separated by a fixed number of resonator roundtrips allows the coherence of Kerr combs to be quantified in terms of the complex-degree of first-order coherence. We identify different regimes of comb coherence, linked to the solutions of the LLE. Our approach provides a practical and unambiguous way of assessing the stability of Kerr combs that is directly connected to an accessible experimental quantity.

  14. Coherence properties of Kerr frequency combs.

    Science.gov (United States)

    Erkintalo, Miro; Coen, Stéphane

    2014-01-15

    We use numerical simulations based on an extended Lugiato-Lefever equation (LLE) to investigate the stability properties of Kerr frequency combs generated in microresonators. In particular, we show that an ensemble average calculated over sequences of output fields separated by a fixed number of resonator roundtrips allows the coherence of Kerr combs to be quantified in terms of the complex degree of first-order coherence. We identify different regimes of comb coherence, linked to the solutions of the LLE. Our approach provides a practical and unambiguous way of assessing the stability of Kerr combs that is directly connected to an accessible experimental quantity.

  15. Cavity quantum electrodynamics: coherence in context.

    Science.gov (United States)

    Mabuchi, H; Doherty, A C

    2002-11-15

    Modern cavity quantum electrodynamics (cavity QED) illuminates the most fundamental aspects of coherence and decoherence in quantum mechanics. Experiments on atoms in cavities can be described by elementary models but reveal intriguing subtleties of the interplay of coherent dynamics with external couplings. Recent activity in this area has pioneered powerful new approaches to the study of quantum coherence and has fueled the growth of quantum information science. In years to come, the purview of cavity QED will continue to grow as researchers build on a rich infrastructure to attack some of the most pressing open questions in micro- and mesoscopic physics.

  16. Second-harmonic optical coherence tomography

    Science.gov (United States)

    Jiang, Yi; Tomov, Ivan; Wang, Yimin; Chen, Zhongping

    2004-05-01

    Second-harmonic optical coherence tomography, which uses coherence gating of second-order nonlinear optical responses of biological tissues for imaging, is described and demonstrated. Femtosecond laser pulses were used to excite second-harmonic waves from collagen harvested from rat tail tendon and a reference nonlinear crystal. Second-harmonic interference fringe signals were detected and used for image construction. Because of the strong dependence of second-harmonic generation on molecular and tissue structures, this technique imparts contrast and resolution enhancement to conventional optical coherence tomography.

  17. Hybrid Rocket Technology

    National Research Council Canada - National Science Library

    Sankaran Venugopal; K K Rajesh; V Ramanujachari

    2011-01-01

    With their unique operational characteristics, hybrid rockets can potentially provide safer, lower-cost avenues for spacecraft and missiles than the current solid propellant and liquid propellant systems...

  18. Hybrid FOSS Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Armstrong researchers are continuing their efforts to further develop FOSS technologies. A hybrid FOSS technique (HyFOSS) employs conventional continuous grating...

  19. From hybrid swarms to swarms of hybrids

    Science.gov (United States)

    Stohlgren, Thomas J.; Szalanski, Allen L; Gaskin, John F.; Young, Nicholas E.; West, Amanda; Jarnevich, Catherine S.; Tripodi, Amber

    2015-01-01

    Science has shown that the introgression or hybridization of modern humans (Homo sapiens) with Neanderthals up to 40,000 YBP may have led to the swarm of modern humans on earth. However, there is little doubt that modern trade and transportation in support of the humans has continued to introduce additional species, genotypes, and hybrids to every country on the globe. We assessed the utility of species distributions modeling of genotypes to assess the risk of current and future invaders. We evaluated 93 locations of the genus Tamarix for which genetic data were available. Maxent models of habitat suitability showed that the hybrid, T. ramosissima x T. chinensis, was slightly greater than the parent taxa (AUCs > 0.83). General linear models of Africanized honey bees, a hybrid cross of Tanzanian Apis mellifera scutellata and a variety of European honey bee including A. m. ligustica, showed that the Africanized bees (AUC = 0.81) may be displacing European honey bees (AUC > 0.76) over large areas of the southwestern U.S. More important, Maxent modeling of sub-populations (A1 and A26 mitotypes based on mDNA) could be accurately modeled (AUC > 0.9), and they responded differently to environmental drivers. This suggests that rapid evolutionary change may be underway in the Africanized bees, allowing the bees to spread into new areas and extending their total range. Protecting native species and ecosystems may benefit from risk maps of harmful invasive species, hybrids, and genotypes.

  20. Coherent receiving efficiency in satellite-ground coherent laser communication system based on analysis of polarization

    Science.gov (United States)

    Hao, Shiqi; Zhang, Dai; Zhao, Qingsong; Wang, Lei; Zhao, Qi

    2017-06-01

    Aimed at analyzing the coherent receiving efficiency of a satellite-ground coherent laser communication system, polarization state of the received light is analyzed. We choose the circularly polarized, partially coherent laser as transmitted light source. The analysis process includes 3 parts. Firstly, an theoretical model to analyze received light's polarization state is constructed based on Gaussian-Schell model (GSM) and cross spectral density function matrix. Then, analytic formulas to calculate coherent receiving efficiency are derived in which both initial ellipticity modification and deflection angle between polarization axes of the received light and the intrinsic light are considered. At last, numerical simulations are operated based on our study. The research findings investigate variations of polarization state and obtain analytic formulas to calculate the coherent receiving efficiency. Our study has theoretical guiding significances in construction and optimization of satellite-ground coherent laser communication system.