WorldWideScience

Sample records for fundamentals polarization mode

  1. Fundamentals of Polarized Light

    Science.gov (United States)

    Mishchenko, Michael

    2003-01-01

    The analytical and numerical basis for describing scattering properties of media composed of small discrete particles is formed by the classical electromagnetic theory. Although there are several excellent textbooks outlining the fundamentals of this theory, it is convenient for our purposes to begin with a summary of those concepts and equations that are central to the subject of this book and will be used extensively in the following chapters. We start by formulating Maxwell's equations and constitutive relations for time- harmonic macroscopic electromagnetic fields and derive the simplest plane-wave solution that underlies the basic optical idea of a monochromatic parallel beam of light. This solution naturally leads to the introduction of such fundamental quantities as the refractive index and the Stokes parameters. Finally, we define the concept of a quasi-monochromatic beam of light and discuss its implications.

  2. Polarization Dependent Whispering Gallery Modes in Microspheres

    Science.gov (United States)

    Adamovsky, Grigory (Inventor); Wrbanek, Susan Y. (Inventor)

    2016-01-01

    A tunable resonant system is provided and includes a microsphere that receives an incident portion of a light beam generated via a light source, the light beam having a fundamental mode, a waveguide medium that transmits the light beam from the light source to the microsphere, and a polarizer disposed in a path of the waveguide between the light source and the microsphere. The incident portion of the light beam creates a fundamental resonance inside the microsphere. A change in a normalized frequency of the wavelength creates a secondary mode in the waveguide and the secondary mode creates a secondary resonance inside the microsphere.

  3. Numerical simulation of fundamental trapped sausage modes

    CERN Document Server

    Cécere, M; Reula, O

    2011-01-01

    Context: We integrate the 2D MHD ideal equations of a straight slab to simulate observational results associated with fundamental sausage trapped modes. Aims: Starting from a non-equilibrium state with a dense chromospheric layer, we analyse the evolution of the internal plasma dynamics of magnetic loops, subject to line-tying boundary conditions, and with the coronal parameters described in Asai et al. (2001) and Melnikov et al. (2002) to investigate the onset and damping of sausage modes. Methods: To integrate the equations we used a high resolution shock-capturing (HRSC) method specially designed to deal appropriately with flow discontinuities. Results: Due to non-linearities and inhomogeneities, pure modes are difficult to sustain and always occur coupled among them so as to satisfy, e.g., the line-tying constraint. We found that, in one case, the resonant coupling of the sausage fundamental mode with a slow one results in a non-dissipative damping of the former. Conclusions: In scenarios of thick and den...

  4. High Polarization Single Mode Photonic Crystal Microlaser

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei; XING Ming-Xin; ZHOU Wen-Jun; LIU An-Jin; ZHENG Wan-Hua

    2009-01-01

    Generally,dipole mode is a doubly degenerate mode.Theoretical calculations have indicated that the single dipole mode of two-dimensional photonic crystal single point defect cavity shows high polarization property.We present a structure with elongated lattice,which only supports a single y-dipole mode.With this structure we can eliminate the degeneracy,control the lasing action of the cavity and demonstrate the high polarization property of the single dipole mode.In our experiment,the polarization extinction ratio of the y-dipole mode is as high as 51:1.

  5. Long wave polar modes in semiconductor heterostructures

    CERN Document Server

    Trallero-Giner, C; Garca̕-Moliner, F 0

    1998-01-01

    Long Wave Polar Modes in Semiconductor Heterostructures is concerned with the study of polar optical modes in semiconductor heterostructures from a phenomenological approach and aims to simplify the model of lattice dynamics calculations. The book provides useful tools for performing calculations relevant to anyone who might be interested in practical applications. The main focus of Long Wave Polar Modes in Semiconductor Heterostructures is planar heterostructures (quantum wells or barriers, superlattices, double barrier structures etc) but there is also discussion on the growing field of quan

  6. Constraining primordial vector mode from B-mode polarization

    Energy Technology Data Exchange (ETDEWEB)

    Saga, Shohei; Ichiki, Kiyotomo [Department of Physics and Astrophysics, Nagoya University, Aichi 464-8602 (Japan); Shiraishi, Maresuke, E-mail: saga.shohei@nagoya-u.jp, E-mail: maresuke.shiraishi@pd.infn.it, E-mail: ichiki@a.phys.nagoya-u.ac.jp [Dipartimento di Fisica e Astronomia ' ' G. Galilei' ' , Università degli Studi di Padova, via Marzolo 8, I-35131, Padova (Italy)

    2014-10-01

    The B-mode polarization spectrum of the Cosmic Microwave Background (CMB) may be the smoking gun of not only the primordial tensor mode but also of the primordial vector mode. If there exist nonzero vector-mode metric perturbations in the early Universe, they are known to be supported by anisotropic stress fluctuations of free-streaming particles such as neutrinos, and to create characteristic signatures on both the CMB temperature, E-mode, and B-mode polarization anisotropies. We place constraints on the properties of the primordial vector mode characterized by the vector-to-scalar ratio r{sub v} and the spectral index n{sub v} of the vector-shear power spectrum, from the Planck and BICEP2 B-mode data. We find that, for scale-invariant initial spectra, the ΛCDM model including the vector mode fits the data better than the model including the tensor mode. The difference in χ{sup 2} between the vector and tensor models is Δχ{sup 2} = 3.294, because, on large scales the vector mode generates smaller temperature fluctuations than the tensor mode, which is preferred for the data. In contrast, the tensor mode can fit the data set equally well if we allow a significantly blue-tilted spectrum. We find that the best-fitting tensor mode has a large blue tilt and leads to an indistinct reionization bump on larger angular scales. The slightly red-tilted vector mode supported by the current data set can also create O(10{sup -22})-Gauss magnetic fields at cosmological recombination. Our constraints should motivate research that considers models of the early Universe that involve the vector mode.

  7. Quantum Statistical Theory of Polarization Mode Dispersion

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong-Sheng; GUO Guang-Can

    2006-01-01

    @@ Polarization mode dispersion is modelled as decoherence of polarization under the disturbance of environment and the coupling with frequency. This model is described by the quantum master equation and the Langevin equation. It can be predicted that the optical beam is depolarized exponentially in a fibre and the differential group delay (DGD) is proportional to the square root of the propagation distance. The distribution of the DGD can also be calculated.

  8. Physical models of polarization mode dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Menyuk, C.R.; Wai, P.K.A. [Univ. of Maryland, Baltimore, MD (United States)

    1995-12-31

    The effect of randomly varying birefringence on light propagation in optical fibers is studied theoretically in the parameter regime that will be used for long-distance communications. In this regime, the birefringence is large and varies very rapidly in comparison to the nonlinear and dispersive scale lengths. We determine the polarization mode dispersion, and we show that physically realistic models yield the same result for polarization mode dispersion as earlier heuristic models that were introduced by Poole. We also prove an ergodic theorem.

  9. Fundamental limits of target detection performance in passive polarization imaging.

    Science.gov (United States)

    Goudail, François; Boffety, Matthieu

    2017-04-01

    We quantitatively determine the target detection performance of different passive polarization imaging architectures perturbed by signal-independent detection noise or signal-dependent Poisson shot noise. We compare the fully adaptive polarimetric imager and the best channel of a static polarimetric imager, and in each case, we compare the use of a polarizer and a polarizing beam splitter as the polarization analyzing device. For all these configurations, we derive a closed-form expression of the target/background separability and quantify the performance gain brought by polarization imaging compared to standard intensity imaging. We show in particular that all the considered polarimetric imaging configurations but one require a minimum value of the polarimetric contrast in order to outperform intensity imaging. The only configuration that always performs better than intensity imaging uses a polarizing beam splitter in the presence of background shot noise. These results are useful in evaluating the fundamental limits of the gain brought by polarization imaging and determining, in practice, which type of imaging architecture is preferable for a given application.

  10. Strong polarization mode coupling in microresonators

    CERN Document Server

    Ramelow, Sven; Clemmen, Stéphane; Levy, Jacob S; Johnson, Adrea R; Okawachi, Yoshitomo; Lamont, Michael R E; Lipson, Michal; Gaeta, Alexander L

    2014-01-01

    We observe strong modal coupling between the TE00 and TM00 modes in Si3N4 ring resonators revealed by avoided crossings of the corresponding resonances. Such couplings result in significant shifts of the resonance frequencies over a wide range around the crossing points. This leads to an effective dispersion that is one order of magnitude larger than the intrinsic dispersion and creates broad windows of anomalous dispersion. We also observe the changes to frequency comb spectra generated in Si3N4 microresonators due polarization mode and higher-order mode crossings and suggest approaches to avoid these effects. Alternatively, such polarization mode-crossings can be used as a novel tool for dispersion engineering in microresonators.

  11. Design of Broadband Single Fundamental Mode Hollow Core Bragg Fibre

    Institute of Scientific and Technical Information of China (English)

    LIN Chen-Xi; ZHANG Wei; HUANG Yi-Dong; PENG Jiang-De

    2008-01-01

    The condition of the single fundamental mode(HE11)transmission in hollow core Bragg fibres is investigated theoretically by the transfer matrix method.The influences of core size and cladding parameters on the single HE11 mode bandwidth are analysed,showing that the maximal bandwidth is more sensirive to the core size than the cladding.The numerical results show that sufficiently broad bandwidth of single HE11 mode transmission can be achieved by proper fibre design.A simple and fast method based on improved hollow metal waveguide model js proposed to optimize fibre structure parameters for the maximal single HE11 mode bandwidth.

  12. Polarization dynamic patterns of vector solitons in a graphene mode-locked fiber laser.

    Science.gov (United States)

    Han, Mengmeng; Zhang, Shumin; Li, Xingliang; Zhang, Huaxing; Yang, Hong; Yuan, Ting

    2015-02-09

    Multiple polarization dynamic patterns of vector solitons, including fundamental solitons, bunched solitons, loosely or tightly bound states and harmonic mode locking have been observed experimentally in an erbium-doped fiber ring laser with graphene as a saturable absorber. By carefully adjusting the pump power and the orientation of the intra-cavity polarization controller, either polarization rotation or polarization locked operation have all been achieved for the above vector solitons. This is the first time that high order harmonic mode locking of polarization rotation vector solitons has been achieved. The signal to noise ratio of our system was ~51 dB, which indicates that the laser operated with high stability.

  13. Relativistic Diskoseismology. III. Low-Frequency Fundamental p-Modes

    CERN Document Server

    Ortega-Rodriguez, M; Wagoner, R V; Ortega-Rodriguez, Manuel; Silbergleit, Alexander S.; Wagoner, Robert V.

    2002-01-01

    We extend our investigation of the normal modes of small adiabatic oscillations of relativistic barotropic thin accretion disks to the inertial-pressure (p) modes. We focus here on the lowest frequency fundamental p-modes, those with no axial or vertical nodes in their distribution. Through a variety of analyses, we obtain closed-form expressions for the eigenfrequencies and eigenfunctions. These depend on the luminosity and viscosity parameter of the disk as well as the mass and angular momentum of the black hole via detailed formulae for the speed of sound. The effect of a torque on the inner edge of the disk is also included. We compare the p-mode properties to those of the g- and c-modes.

  14. Additional Raman Scattering Mechanism due to Transverse Polar Modes

    Institute of Scientific and Technical Information of China (English)

    CHENG Ze

    2001-01-01

    Longitudinal polar modes generate a macroscopic electric field in piezoelectric crystals and cause an additional mechanism of Raman scattering. The classical theory holds that transverse polar modes cannot produce such an additional mechanism. Our quantum theory shows that there is an additional Raman scattering mechanism arising from the electro-optic effect of transverse polar modes.``

  15. Mode evolution in polarization maintain few mode fibers and applications in mode-division-multiplexing systems

    Science.gov (United States)

    Li, Yan; Zeng, Xinglin; Mo, Qi; Li, Wei; Liu, Zhijian; Wu, Jian

    2016-10-01

    In few-mode polarization-maintaining-fiber (FM-PMF), the effective-index splitting exists not only between orthogonally polarization state but also between degenerated modes within a high-order mode group. Hence besides the polarization state evolution, the mode patterns in each LP set are need to be analyzed. In this letter, the completed firstorder mode (LP11 mode) evolution in PM-FMF is analyzed and represented by analogous Jones vector and Poincarésphere respectively. Furthermore, with Jones matrix analysis, the modal dynamics in FM-PMFs is conveniently analyzed. The conclusions are used to propose a PM-FMF based LP11 mode rotator and an PM-FMF based OAM generator. Both simulation and experiments are conducted to investigate performance of the two devices.

  16. Ordinary-mode fundamental electron cyclotron resonance absorption and emission in the Princeton Large Torus

    Energy Technology Data Exchange (ETDEWEB)

    Efthimion, P.C.; Arunasalam, V.; Hosea, J.C.

    1979-11-01

    Fundamental electron cyclotron resonance damping for 4 mm waves with ordinary polarization is measured for propagation along the major radius traversing the midplane of the plasma in the Princeton Large Torus (PLT). Optical depths obtained from the data are in good agreement with those predicted by the relativistic hot plasma theory. Near blackbody emission over much of the plasma midplane is obtained and, in conjunction with the damping measurements, indicates that the vessel reflectivity is high. The practical use of ordinary mode fundamental electron cyclotron resonance heating (ECRH) in existing and future toroidal devices is supported by these results.

  17. Polarization Properties of A Multi-Moded Concentrator

    CERN Document Server

    Kogut, A; Hill, R S

    2015-01-01

    We present the design and performance of a non-imaging concentrator for use in broad-band polarimetry at millimeter through submillimeter wavelengths. A rectangular geometry preserves the input polarization state as the concentrator couples f/2 incident optics to a 2 pi sr detector. Measurements of the co-polar and cross-polar beams in both the few-mode and highly over-moded limits agree with a simple model based on mode truncation. The measured co-polar beam pattern is nearly independent of frequency in both linear polarizations. The cross-polar beam pattern is dominated by a uniform term corresponding to polarization efficiency 94%. After correcting for efficiency, the remaining cross-polar response is -18 dB.

  18. Polarization dynamics in dissipative soliton fiber lasers mode-locked by nonlinear polarization rotation.

    Science.gov (United States)

    Kong, Lingjie; Xiao, Xiaosheng; Yang, Changxi

    2011-09-12

    We numerically studied the polarization dynamics in dissipative soliton lasers mode-locked by nonlinear polarization rotation (NPR). It was found that the polarization states of the intracavity dissipative soliton vary with time across the pulse. Depending on output coupling ratios, the polarization states of the pulse peak before the polarizer can be either nearly circular or nearly linear polarizations. The polarization dependent component in NPR is found to play a role of spectral filter under high and medium output coupling. However, NPR may work as a weak optical limiter under low output coupling, when additional spectral filtering is necessary to maintain steady mode-locking state.

  19. Distributed measurement of mode coupling in birefringent fibers with random polarization modes

    CERN Document Server

    Xu, Tianhua; Jing, Wencai; Zhang, Hongxia; Jia, Dagong; Zhang, Xuemin; Zhou, Ge; Zhang, Yimo

    2016-01-01

    A scanning white light interferometer is developed to measure the distributed polarization coupling (DPC) in high birefringence polarization maintaining fibers (PMFs). Traditionally, this technique requests only one polarization mode to be excited or both polarization modes to be excited with equal intensity in the PMF. Thus, an accurate alignment of the polarization direction with the principal axis in PMF is strictly required, which is not facilely realized in practical measurement. This paper develops a method to measure the spatial distribution of polarization mode coupling with random modes excited using a white light Michelson interferometer. The influence of incident polarization extinction ratio (PER) on polarization coupling detection is evaluated theoretically and experimentally. It is also analyzed and validated in corresponding measurement that the sensitivity of the polarization coupling detection system can be improved more than 100 times with the rotation of the analyzer.

  20. Polarization maintaining large-mode area photonic crystal fibre

    DEFF Research Database (Denmark)

    Folkenberg, Jacob Riis; Nielsen, Martin Dybendal; Mortensen, N.A.

    2004-01-01

    We report on a polarization maintaining large mode area photonic crystal fiber. Unlike, previous work on polarization maintaining photonic crystal fibers, birefringence is introduced using stress applying parts. This has allowed us to realize fibers, which are both single mode at any wavelength a...

  1. Optimum Position of Polarizer-Based Compensator for Enhanced Tolerance to Polarization Mode Dispersion

    Institute of Scientific and Technical Information of China (English)

    Daniele; Alzetta; Masayuki; Matsumoto

    2003-01-01

    We show through numerical simulation that the performance of two types of polarization-mode dispersion polarizer-based compensation techniques may be improved by optimizing the position of the compensator along the transmission line.

  2. Electrically controlled optical-mode switch for fundamental mode and first order mode

    Science.gov (United States)

    Imansyah, Ryan; Tanaka, Tatsushi; Himbele, Luke; Jiang, Haisong; Hamamoto, Kiichi

    2016-08-01

    We have proposed an optical mode switch, the principle of which is based on the partial phase shift of injected light; therefore, one important issue is to clarify the proper design criteria for the mode combiner section. We focused on the bending radius of the S-bend waveguide issue that is connected to the multi mode waveguide in the Y-junction section that acts as mode combiner. Long radius leads to undesired mode coupling before the Y-junction section, whereas a short radius causes radiation loss. Thus, we simulated this mode combiner by the beam-propagation method to obtain the proper radius. In addition, we used a trench pin structure to simplify the fabrication process into a single-step dry-etching process. As a result, we successfully fabricated an optical-mode switch with the bending radius R = 610 µm. It showed the successful electrical mode switching and the achieved mode crosstalk was approximately -10 dB for 1550 nm wavelength with the injection current of 60 mA (5.7 V).

  3. Very-large-mode-area photonic bandgap Bragg fiber polarizing in a wide spectral range.

    Science.gov (United States)

    Aleshkina, Svetlana S; Likhachev, Mikhail E; Pryamikov, Andrey D; Gaponov, Dmitry A; Denisov, Alexandr N; Bubnov, Mikhail M; Salganskii, Mikhail Yu; Laptev, Alexandr Yu; Guryanov, Aleksei N; Uspenskii, Yurii A; Popov, Nikolay L; Février, Sébastien

    2011-09-15

    A design of a polarizing all-glass Bragg fiber with a microstructure core has been proposed for the first time. This design provides suppression of high-order modes and of one of the polarization states of the fundamental mode. The polarizing fiber was fabricated by a new, simple method based on a combination of the modified chemical vapor deposition (MCVD) process and the rod-in-tube technique. The mode field area has been found to be about 870 μm² near λ=1064 nm. The polarization extinction ratio better than 13 dB has been observed over a 33% wavelength range (from 1 to 1.4 μm) after propagation in a 1.7 m fiber piece bent to a radius of 70 cm.

  4. Vectorial platform for manipulating the polarization mode train realized with Jones vectors in Mathematica

    Science.gov (United States)

    Kim, Tae Wan; Yun, Hee-Joong

    2016-09-01

    A fundamental concept in physics of polarization propagation of electromagnetic waves is newly understood as a cardinal keyword in quantum cryptography transport technology and cosmology. Recently, interactive visualization of the propagation mechanism of polarized electromagnetism in a medium with helicity has received attention from scientists in the age of information and communication. This study presents a new dynamic polarization platform that manipulates the polarization mode train of a transverse electromagnetic wave by using calculations with Jones vectors in the symbolic program Mathematica. The train of polarization modes is converted continuously through a desirable lineup of optical elements in the platform. The platform simulates a propagation process that satisfies Maxwell's two vector equations precisely with helicity in the vectorial nature of the electromagnetic wave.

  5. Exploring the self-mode-locked dynamics of cryogenic diode-pumped Nd:YLF lasers: switching of orthogonal polarizations

    Science.gov (United States)

    Huang, T. L.; Y Cho, C.; Liang, H. C.; Huang, K. F.; Chen, Y. F.

    2017-08-01

    The self-mode-locked output for cryogenic Nd:YLF laser at the temperature range of 90 K to 290 K is thoroughly investigated. Linearly polarized self-mode-locked lasing at 1047 nm (1053 nm) with a repetition rate up to 1.59 GHz and a pulse width as short as 52 ps can be realized at temperatures above 155 K (below 135 K). Orthogonally polarized self-mode-locked operation can be observed at temperatures near 145 K. During dual-polarization operation, it is found that the polarized component with higher output power is the fundamental transverse mode, whereas the other component with lower output power becomes the high-order transverse mode. The dominant polarized component can be either π- or σ-polarization, depending on the fine adjustment of the cavity.

  6. Polarization Mode Dispersion Probability Distribution for Arbitrary Mode Coupling

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The probability distribution of the differential group delay for arbitrary mode coupling is simulated with Monte-Carlo method. Fitting the simulation results, we obtain probability distribution function for arbitrary mode coupling.

  7. Simultaneous demodulation of polarization mode coupling and fiber Bragg grating within a polarization maintaining fiber

    Science.gov (United States)

    Zhao, Yanshuang; Liu, Yanlei; Zhang, Jianzhong; Yang, Jun; Canning, John; Peng, G. D.; Chen, Yujin; Yuan, Libo

    2015-09-01

    We propose a simultaneous demodulation scheme of polarization mode coupling and fiber Bragg grating in a polarization maintaining fiber based on a white light interferometer. A polarization maintaining fiber with two inscribed fiber Bragg gratings is used to demonstrate the feasibility.

  8. Carbon nanotubes for mode-locking: polarization study

    Science.gov (United States)

    Afkhamiardakani, Hanieh; Kamer, Brian; Diels, Jean-Claude; Arissian, Ladan

    2016-03-01

    Mode-locked fiber lasers are the most promising lasers for intracavity phase interferometry,1 because they offer the possibility to have two orthogonally polarized pulses circulating independently in the cavity. The saturable absorbers based on polarization maintaining tapered fiber coated with carbon nanotubes are developed and analyzed for minimum coupling between the slow and fast axis of the fiber.

  9. Dual-polarization mode-locked Nd:YAG laser.

    Science.gov (United States)

    Thévenin, J; Vallet, M; Brunel, M

    2012-07-15

    A mode-locked solid-state laser containing a birefringent element is shown to emit synchronously two frequency combs associated to the two polarization eigenstates of the cavity. An analytical model predicts the polarization evolution of the pulse train, which is determined by the adjustable intracavity birefringence. Experiments realized with a Nd:YAG laser passively mode locked by a semiconductor saturable absorber mirror are in perfect agreement with the model. Locking between the two combs arises for particular values of their frequency difference, e.g., half the repetition rate, and the pulse train polarization sequence is then governed by the relative overall phase offset of the two combs.

  10. Quantum noise in a laser with nonorthogonal polarization modes

    NARCIS (Netherlands)

    van der Lee, A.M.; Mieremet, A.L.; van Exter, M.P.; van Druten, N.J.; Woerdman, J.P.

    2000-01-01

    We describe the quantum-noise behavior of a laser that has nonorthogonal polarization modes. The nonorthogonality of the modes leads to excess quantum noise. Theoretically, we derive the excess noise dynamics of the laser, including the saturation of the gain medium. Experimentally, we have measured

  11. Polarization-selective out-coupling of whispering gallery modes

    CERN Document Server

    Sedlmeir, Florian; Vogl, Ulrich; Zeltner, Richard; Schunk, Gerhard; Strekalov, Dmitry V; Marquardt, Christoph; Leuchs, Gerd; Schwefel, Harald G L

    2016-01-01

    Whispering gallery mode (WGM) resonators are an important building block for linear, nonlinear and quantum optical experiments. In such experiments, independent control of coupling rates to different modes can lead to improved conversion efficiencies and greater flexibility in generation of non-classical states based on parametric down conversion. In this work, we introduce a scheme which enables selective out-coupling of WGMs belonging to a specific polarization family, while the orthogonally polarized modes remain largely unperturbed. Our technique utilizes material birefringence in both the resonator and coupler such that a negative (positive) birefringence allows selective coupling to TE (TM) polarized WGMs. We formulate a new coupling condition suitable for describing the case where the refractive indices of the resonator and the coupler are almost the same, from which we derive the criterion for polarization-selective coupling. We experimentally demonstrate our proposed method using a lithium niobate di...

  12. Selection of a LGp0-shaped fundamental mode in a laser cavity: Phase versus amplitude masks

    CSIR Research Space (South Africa)

    Hasnaoui, A

    2012-01-01

    Full Text Available Laser beams of a single high-order transverse mode have been of interest to the laser community for several years now. In order to achieve such a mode as the fundamental mode of the cavity, mode selecting elements in the form of a phase or amplitude...

  13. Mode-field half-widths of Gaussian approximation for the fundamental mode of two kinds of optical waveguides

    Institute of Scientific and Technical Information of China (English)

    Li Lian-Huang; Guo Fu-Yuan

    2009-01-01

    This paper analyzes the characteristic of matching efficiency between the fundamental mode of two kinds of optical waveguides and its Gaussian approximate field.Then, it presents a new method where the mode-field half-width of Gaussian approximation for the fundamental mode should be defined according to the maximal matching efficiency method. The relationship between the mode-field half-width of the Gaussian approximate field obtained from the maximal matching efficiency and normalized frequency is studied; furthermore, two formulas of mode-field half-widths as a function of normalized frequency are proposed.

  14. Fundamental uncertainty in the BAO scale from isocurvature modes

    Energy Technology Data Exchange (ETDEWEB)

    Zunckel, C., E-mail: caroline.zunckel@gmail.co [Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, University of Kwazulu-Natal, Durban 4041 (South Africa); Astrophysics Department, Princeton University, Peyton Hall, 4 Ivy Lane, NJ 08544 (United States); Okouma, P. [Department of Maths and Applied Maths, University of Cape Town, Rondebosch 7701, Cape Town (South Africa); Centre for High Performance Computing, CSIR Campus, 15 Lower Hope St., Rosebank, Cape Town (South Africa); South African Astronomical Observatory, Observatory, Cape Town (South Africa); African Institute for Mathematical Sciences, 6-8 Melrose Road, Muizenberg, Cape Town (South Africa); Muya Kasanda, S.; Moodley, K. [Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, University of Kwazulu-Natal, Durban 4041 (South Africa); Centre for High Performance Computing, CSIR Campus, 15 Lower Hope St., Rosebank, Cape Town (South Africa); Bassett, B.A. [Department of Maths and Applied Maths, University of Cape Town, Rondebosch 7701, Cape Town (South Africa); Centre for High Performance Computing, CSIR Campus, 15 Lower Hope St., Rosebank, Cape Town (South Africa); South African Astronomical Observatory, Observatory, Cape Town (South Africa); African Institute for Mathematical Sciences, 6-8 Melrose Road, Muizenberg, Cape Town (South Africa)

    2011-02-14

    Small fractions of isocurvature perturbations correlated with the dominant adiabatic mode are shown to be a significant primordial systematic for Baryon Acoustic Oscillation (BAO) surveys which must be accounted for in future surveys. Isocurvature modes distort the standard ruler distance by broadening and shifting the peak in the galaxy correlation function. While a single isocurvature mode does not significantly degrade dark energy constraints, the general case with multiple isocurvature modes leads to biases that exceed 7{sigma} on average in the dark energy parameters even for isocurvature amplitudes undetectable by PLANCK. Accounting for all isocurvature modes corrects for this bias but degrades the dark energy figure of merit by at least 50% in the case of the BOSS experiment. However the BAO data in turn provides significantly stronger constraints on the nature of the primordial perturbations. Future large galaxy surveys will thus be powerful probes of exotic physics in the early Universe in addition to helping pin down the nature of dark energy.

  15. Automation of Mode Locking in a Nonlinear Polarization Rotation Fiber Laser through Output Polarization Measurements.

    Science.gov (United States)

    Olivier, Michel; Gagnon, Marc-Daniel; Habel, Joé

    2016-02-28

    When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a new and inexpensive procedure to force mode locking in a pre-adjusted nonlinear polarization rotation fiber laser. This procedure is based on the detection of a sudden change in the output polarization state when mode locking occurs. This change is used to command the alignment of the intra-cavity polarization controller in order to find mode-locking conditions. More specifically, the value of the first Stokes parameter varies when the angle of the polarization controller is swept and, moreover, it undergoes an abrupt variation when the laser enters the mode-locked state. Monitoring this abrupt variation provides a practical easy-to-detect signal that can be used to command the alignment of the polarization controller and drive the laser towards mode locking. This monitoring is achieved by feeding a small portion of the signal to a polarization analyzer measuring the first Stokes parameter. A sudden change in the read out of this parameter from the analyzer will occur when the laser enters the mode-locked state. At this moment, the required angle of the polarization controller is kept fixed. The alignment is completed. This procedure provides an alternate way to existing automating procedures that use equipment such as an optical spectrum analyzer, an RF spectrum analyzer, a photodiode connected to an electronic pulse-counter or a nonlinear detecting scheme based on two-photon absorption or second harmonic generation. It is suitable for lasers mode locked by nonlinear polarization rotation. It is relatively easy to implement, it requires inexpensive means, especially at a wavelength of 1550 nm, and it lowers the production and operation costs incurred in comparison to the above-mentioned techniques.

  16. Two-mode polarized traveling wave deflecting structure

    Institute of Scientific and Technical Information of China (English)

    谭建豪; 顾强; 方文程; 童德春; 赵振堂

    2015-01-01

    In this paper, we propose a two-mode polarizable deflecting structure, as a new concept for bunch measure-ment and beam control. With two modes of HEM11 and HEM12 operating in the same structure on horizontal and vertical directions, respectively, the operation status can be switched between the two polarization modes. They can be operated simultaneously with two independent input power sources. With two-mode deflecting structure, the bunch distortion caused by the geometric wake-fields in the accelerating structure can be mea-sured by one structure.

  17. CMB Polarization B-mode Delensing with SPTpol and Herschel

    Science.gov (United States)

    Manzotti, A.; Story, K. T.; Wu, W. L. K.; Austermann, J. E.; Beall, J. A.; Bender, A. N.; Benson, B. A.; Bleem, L. E.; Bock, J. J.; Carlstrom, J. E.; Chang, C. L.; Chiang, H. C.; Cho, H.-M.; Citron, R.; Conley, A.; Crawford, T. M.; Crites, A. T.; de Haan, T.; Dobbs, M. A.; Dodelson, S.; Everett, W.; Gallicchio, J.; George, E. M.; Gilbert, A.; Halverson, N. W.; Harrington, N.; Henning, J. W.; Hilton, G. C.; Holder, G. P.; Holzapfel, W. L.; Hoover, S.; Hou, Z.; Hrubes, J. D.; Huang, N.; Hubmayr, J.; Irwin, K. D.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Li, D.; McMahon, J. J.; Meyer, S. S.; Mocanu, L. M.; Natoli, T.; Nibarger, J. P.; Novosad, V.; Padin, S.; Pryke, C.; Reichardt, C. L.; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Schaffer, K. K.; Smecher, G.; Stark, A. A.; Vanderlinde, K.; Vieira, J. D.; Viero, M. P.; Wang, G.; Whitehorn, N.; Yefremenko, V.; Zemcov, M.

    2017-09-01

    We present a demonstration of delensing the observed cosmic microwave background (CMB) B-mode polarization anisotropy. This process of reducing the gravitational-lensing-generated B-mode component will become increasingly important for improving searches for the B modes produced by primordial gravitational waves. In this work, we delens B-mode maps constructed from multi-frequency SPTpol observations of a 90 deg2 patch of sky by subtracting a B-mode template constructed from two inputs: SPTpol E-mode maps and a lensing potential map estimated from the Herschel 500 μm map of the cosmic infrared background. We find that our delensing procedure reduces the measured B-mode power spectrum by 28% in the multipole range 300importance of including realistic experimental non-idealities in the delensing forecasts used to inform instrument and survey-strategy planning of upcoming lower-noise experiments, such as CMB-S4.

  18. Polarization Dependent Coupling of Whispering Gallery Modes in Microspheres

    Science.gov (United States)

    Adamovsky, G.; Wrbanek, S.; Floyd, B.; Crotty, M.

    2010-01-01

    Two sets of resonances in glass microspheres attached to a standard communication-grade single-mode optical fiber have been observed. It has been found that the strength of the resonances depends strongly on the polarization of the coupled light. Furthermore, the position of the resonances in the wavelength domain depends on the polarization of light in the optical fiber with maximum magnitudes shifted by approximately 45 .

  19. Coupled-mode equation of polarization modes of twisted birefringent fibers in a unified coordinate.

    Science.gov (United States)

    Fang, Zujie; Yang, Fei; Cai, Haiwen; Qu, Ronghui

    2013-01-20

    A coupled-mode equation (CME) of twisted birefringent fiber is presented in this paper, which uses the degenerate polarization modes of single-mode fibers as eigenmodes in a unified coordinate. The inconsistency between the coordinate and the rotating principal axis, existing in the previous CME, is solved by conversion to the lab coordinate. The CME gives self-consistent results for fibers with high birefringence or low birefringence and for single-mode fibers as well. Analyses and simulations show the CME gives characteristics of twisted birefringent fiber coincident with the property of polarization-maintaining fibers.

  20. Design of eight-mode polarization-maintaining few-mode fiber for multiple-input multiple-output-free spatial division multiplexing.

    Science.gov (United States)

    Wang, Lixian; LaRochelle, Sophie

    2015-12-15

    We propose a polarization-maintaining few-mode fiber (FMF) that features an elliptical ring shaped core with a high refractive index contrast ∼0.03 between the core and the cladding. This fiber design alleviates the usual trade-off between the number of guided modes and the achievable birefringence that is usually observed in conventional elliptical-core FMFs. Through numerical simulations, we show that this fiber design can support up to 10 guided vector modes over the entire C band while providing large birefringence. Except for the two fundamental modes, the eight higher-order vector modes are all separated from their adjacent modes by effective index differences >10⁻⁴, which is the typical birefringence value of single-mode polarization maintaining fibers. The designed fiber targets applications in spatial division multiplexing of optical channels, without multiple-input-multiple-output (MIMO) digital signal processing, for short-reach optical interconnects.

  1. Study of the stability of polarization mode dispersion in fibre

    Institute of Scientific and Technical Information of China (English)

    付松年; 吴重庆; 刘海涛; 沈平; 董晖

    2003-01-01

    Polarization mode dispersion (PMD) is the ultimate limitation to high bit-rate fibre communication system. The stability of PMD is very important to its measurement and compensation. This paper puts forward a method to measure the stability of PMD by measuring the stability of the state of polarization (SOP) and introduces the conception of time evolution vector (TEV) of SOP. We observe the fact that the regularity of the principal state of polarization changing with time is the same as other SOPs', if we neglect the dependence of TEV on wavelength. We also measure the SOP's stability of some fibres with different lengths, and obtain results of PMD changing with time.

  2. Design and optimization of fundamental mode filters based on long-period fiber gratings

    Science.gov (United States)

    Chen, Ming-Yang; Wei, Jin; Sheng, Yong; Ren, Nai-Fei

    2016-07-01

    A segment of long-period fiber grating (LPFG) that can selectively filter the fundamental mode in the few-mode optical fiber is proposed. By applying an appropriate chosen surrounding material and an apodized configuration of LPFG, high fundamental mode loss and low high-order core mode loss can be achieved simultaneously. In addition, we propose a method of cascading LPFGs with different periods to expand the bandwidth of the mode filter. Numerical simulation shows that the operating bandwidth of the cascade structure can be as large as 23 nm even if the refractive index of the surrounding liquid varies with the environment temperature.

  3. Ortho-mode Vivaldi antennas for agile polarization systems

    Science.gov (United States)

    Macedo, A. D.; Mosso, M. M.

    The design criteria and assembly techniques for the ortho-mode Vivaldi (OMV) antenna system are described. The system is composed of a set of two orthogonal linearly polarized elements that are fed by an ortho-mode tee. The performances of two prototype OMV antennas system are examined and the applicability OMV is noted. Diagrams of the two prototypes and graphs of their performance are provided.

  4. Gravitational wave polarization modes in $f(R)$ theories

    CERN Document Server

    Rizwana, Kausar H; Philippe, Jetzer

    2016-01-01

    Many studies have been carried out in the literature to evaluate the number of polarization modes of gravitational waves in modified theories, in particular in $f(R)$ theories. In the latter ones, besides the usual two transverse-traceless tensor modes present in general relativity, there are two additional scalar ones: a massive longitudinal mode and a massless transverse mode (the so-called breathing mode). This last mode has often been overlooked in the literature, due to the assumption that the application of the Lorenz gauge implies transverse-traceless wave solutions. We however show that this is in general not possible and, in particular, that the traceless condition cannot be imposed due to the fact that we no longer have a Minkowski background metric. Our findings are in agreement with the results found using the Newman-Penrose formalism, and thus clarify the inconsistencies found so far in the literature.

  5. Optical injection induced polarization mode switching and correlation analysis on a VCSEL

    CERN Document Server

    Damodarakurup, Sajeev; Vudayagiri, Ashok

    2015-01-01

    Vertical cavity Surface Emitting Laser (VCSEL) diodes emit light in two polarization modes. The amount of optical feedback is found to influence the intensities of the emitted modes. We investigate the effect of the amount of total output polarization feedback and polarization selective feedback on the intensities of the two emitted polarization modes. A 40 micro seconds resolution time series correlation analysis is done for different feedback conditions and investigate the power spectral continuity and onset of chaos on two polarization modes

  6. Sensitivity and foreground modelling for large-scale CMB B-mode polarization satellite missions

    CERN Document Server

    Remazeilles, M; Eriksen, H K K; Wehus, I K

    2015-01-01

    Measurements of large-scale B-mode polarization in the cosmic microwave background (CMB) are a fundamental goal of current and future CMB experiments. However, because of the much higher instrumental sensitivity, CMB experiments will be more sensitive to any imperfect modelling of the Galactic foreground polarization in the estimation of the primordial B-mode signal. We compare the sensitivity to B-modes for different concepts of CMB satellite missions (LiteBIRD, COrE, COrE+, PRISM, EPIC, PIXIE) in the presence of Galactic foregrounds that are either correctly or incorrectly modelled. We quantify the impact on the tensor-to-scalar parameter of imperfect foreground modelling in the component separation process. Using Bayesian parametric fitting and Gibbs sampling, we perform the separation of the CMB and the Galactic foreground B-mode polarization. The resulting CMB B-mode power spectrum is used to compute the likelihood distribution of the tensor-to-scalar ratio. We focus the analysis to the very large angula...

  7. Transfer efficiency of angular momentum in sum-frequency generation and control of its spin and orbital parts by varying polarization and frequency of fundamental beams

    Science.gov (United States)

    Perezhogin, I. A.; Grigoriev, K. S.; Potravkin, N. N.; Cherepetskaya, E. B.; Makarov, V. A.

    2017-08-01

    Considering sum-frequency generation in an isotropic chiral nonlinear medium, we analyze the transfer of the spin angular momentum of fundamental elliptically polarized Gaussian light beams to the signal beam, which appears as the superposition of two Laguerre-Gaussian modes with both spin and orbital angular momentum. Only for the circular polarization of the fundamental radiation is its angular momentum fully transferred to the sum-frequency beam; otherwise, part of it can be transferred to the medium. Its value, as well as the ratio of spin and orbital contributions in the signal beam, depends on the fundamental frequency ratio and the polarization of the incident beams. Higher energy conversion efficiency in sum-frequency generation does not always correspond to higher angular momentum conversion efficiency.

  8. Reduction of mode Q-factor due to coupling between fundamental and first order whispering-gallery modes in coupled microdisks

    Institute of Scientific and Technical Information of China (English)

    LI Jun-jie; WANG Jia-xian; HUANG Yong-zhen

    2007-01-01

    The mode characteristics for twin coupled microdisks are investigated by fmite-difference time-domain technique. In the coupled microdisks, the same order whispering-gallery (WG) modes can form coupled modes with split mode wavelengths.We find that the coupled fundamental and first order WG modes can have anticrossing mode coupling as their wavelengths approach the same value in some case, which prevents the cross of the coupled mode wavelengths. The anticrossing mode coupling greatly reduces the coupled mode Q-factor, because the coupled mode field distribution transfers between the fundamental and the first order WG modes.

  9. CMB Polarization B-mode Delensing with SPTpol and Herschel

    Energy Technology Data Exchange (ETDEWEB)

    Manzotti, A.; et al.

    2017-01-16

    We present a demonstration of delensing the observed cosmic microwave background (CMB) B-mode polarization anisotropy. This process of reducing the gravitational-lensing generated B-mode component will become increasingly important for improving searches for the B modes produced by primordial gravitational waves. In this work, we delens B-mode maps constructed from multi-frequency SPTpol observations of a 90 deg$^2$ patch of sky by subtracting a B-mode template constructed from two inputs: SPTpol E-mode maps and a lensing potential map estimated from the $\\textit{Herschel}$ $500\\,\\mu m$ map of the CIB. We find that our delensing procedure reduces the measured B-mode power spectrum by 28% in the multipole range $300 < \\ell < 2300$; this is shown to be consistent with expectations from theory and simulations and to be robust against systematics. The null hypothesis of no delensing is rejected at $6.9 \\sigma$. Furthermore, we build and use a suite of realistic simulations to study the general properties of the delensing process and find that the delensing efficiency achieved in this work is limited primarily by the noise in the lensing potential map. We demonstrate the importance of including realistic experimental non-idealities in the delensing forecasts used to inform instrument and survey-strategy planning of upcoming lower-noise experiments, such as CMB-S4.

  10. Establishing the origin of CMB B-mode polarization

    CERN Document Server

    Sheere, Connor; Meerburg, P Daniel; Meyers, Joel

    2016-01-01

    Primordial gravitational waves leave a characteristic imprint on the cosmic microwave background (CMB) in the form of $B$-mode polarization. Photons are also deflected by large scale gravitational waves which intervene between the source screen and our telescopes, resulting in curl-type gravitational lensing. Gravitational waves present at the epoch of reionization contribute to both effects, thereby leading to a non-vanishing cross-correlation between $B$-mode polarization and curl lensing of the CMB. Observing such a cross correlation would be very strong evidence that an observation of $B$-mode polarization was due to the presence of large scale gravitational waves, as opposed to astrophysical foregrounds or experimental systematic effects. We study the cross-correlation across a wide range of source redshifts and show that a post-SKA experiment aimed to map out the 21-cm sky between $15 \\leq z \\leq 30$ could rule out non-zero cross-correlation at high significance for $r \\geq 0.01$.

  11. B-mode in CMB polarization. What's that and why it is interesting

    CERN Document Server

    Dolgov, A D

    2014-01-01

    Generation of the B-mode of CMB polarization by background of relic gravitational wave is discussed in connection with the BICEP2 measurements. Description of the polarization maps in terms of the eigenvectors of the polarization matrix is considered.

  12. Automated mode locking in nonlinear polarization rotation fiber lasers by detection of a discontinuous jump in the polarization state.

    Science.gov (United States)

    Olivier, Michel; Gagnon, Marc-Daniel; Piché, Michel

    2015-03-09

    A strategy to align a mode-locked fiber laser with nonlinear polarization rotation is presented. This strategy is based on measurements of the output polarization state. It is shown that, as the angle of a motorized polarization controller inside the cavity is swept, the laser eventually reaches a mode-locked regime and the values of the Stokes parameters undergo an abrupt change. The sensing of this sudden variation is thus used to detect the mode-locking condition and a feedback mechanism drives the alignment of the polarization controller to force mode locking.

  13. 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.

  14. Excess B-modes extracted from the Planck polarization maps

    Science.gov (United States)

    Nørgaard-Nielsen, H. U.

    2016-07-01

    One of the main obstacles for extracting the Cosmic Microwave Background (CMB) from mm/submm observations is the pollution from the main Galactic components: synchrotron, free-free and thermal dust emission. The feasibility of using simple neural networks to extract CMB has been demonstrated on both temperature and polarization data obtained by the WMAP satellite. The main goal of this paper is to demonstrate the feasibility of neural networks for extracting the CMB signal from the Planck polarization data with high precision. Both auto-correlation and cross-correlation power spectra within a mask covering about 63 % of the sky have been used together with a ``high pass filter'' in order to minimize the influence of the remaining systematic errors in the Planck Q and U maps. Using the Planck 2015 released polarization maps, a BB power spectrum have been extracted by Multilayer Perceptron neural networks. This spectrum contains a bright feature with signal to noise ratios ≃ 4.5 within 200 ≤ l ≤ 250. The spectrum is significantly brighter than the BICEP2 2015 spectrum, with a spectral behaviour quite different from the ``canonical'' models (weak lensing plus B-modes spectra with different tensor to scalar ratios). The feasibility of the neural network to remove the residual systematics from the available Planck polarization data to a high level has been demonstrated.

  15. Solvent density mode instability in non-polar solutions

    Indian Academy of Sciences (India)

    Susmita Kar; Ranjit Biswas; J Chakrabarti

    2008-08-01

    We analyse the origin of the multiple long time scales associated with the long time decay observed in non-polar solvation dynamics by linear stability analysis of solvent density modes where the effects of compressibility and solvent structure are systematically incorporated. The coupling of the solute–solvent interactions at both ground and excited states of the solute with the compressibility and solvent structure is found to have important effects on the time scales. The present theory suggests that the relatively longer time constant is controlled by the solvent compressibility, while the solvent structure at the nearest-neighbour length scale dominates the shorter time constant.

  16. Geometric algebra description of polarization mode dispersion, polarization-dependent loss, and Stokes tensor transformations.

    Science.gov (United States)

    Soliman, George; Yevick, David; Jessop, Paul

    2014-09-01

    This paper demonstrates that numerous calculations involving polarization transformations can be condensed by employing suitable geometric algebra formalism. For example, to describe polarization mode dispersion and polarization-dependent loss, both the material birefringence and differential loss enter as bivectors and can be combined into a single symmetric quantity. Their frequency and distance evolution, as well as that of the Stokes vector through an optical system, can then each be expressed as a single compact expression, in contrast to the corresponding Mueller matrix formulations. The intrinsic advantage of the geometric algebra framework is further demonstrated by presenting a simplified derivation of generalized Stokes parameters that include the electric field phase. This procedure simultaneously establishes the tensor transformation properties of these parameters.

  17. On the shape of the fundamental sloshing mode in axisymmetric containers

    CERN Document Server

    Kulczycki, Tadeusz; Siudeja, Bartłomiej

    2014-01-01

    In the paper we numerically study positions of high spots (extrema) of the fundamental sloshing mode of liquid in an axisymmetric tank. Our approach is based on a linear model reducing the problem to appropriate Steklov eigenvalue problem. We propose a numerical scheme for calculating sloshing modes and a novel method of making images of oscillating fluid. We also describe the relation of the high spot problem to the celebrated hot spots conjecture.

  18. Extracting fundamental transverse mode operation in broad area quantum cascade lasers

    Science.gov (United States)

    Kaspi, R.; Luong, S.; Yang, C.; Lu, C.; Newell, T. C.; Bate, T.

    2016-11-01

    Power scaling in broad area quantum cascade lasers results in the operation of high order transverse modes with a far-field profile consisting of two lobes propagating at large angles relative to the optical axis. We report a method of suppressing the high order transverse modes that can extract the fundamental mode and provide emission along the optical axis. By generating a lateral constriction in the waveguide in the form of short trenches defined by the focused ion beam milling technique, we report broad area devices in which most of the power is contained in a near diffraction-limited beam that provides high brightness.

  19. Coupling of energy into the fundamental diffusion mode of a complex nanophotonic medium

    NARCIS (Netherlands)

    Ojambati, O. S.; Yilmaz, H.; Lagendijk, A.; Mosk, A. P.; Vos, W.L.

    2016-01-01

    We demonstrate experimentally that optical wavefront shaping increases light coupling into the fundamental diffusion mode of a scattering medium. The total energy density inside a scattering medium of zinc oxide nanoparticles was probed by exciting fluorescent spheres that were randomly positioned

  20. On the fundamental mode of the optical resonator with toroidal mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Serednyakov, S.S.; Vinokurov, N.A. [Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation)

    1995-12-31

    The fundamental mode of the optical resonator with the toroidal mirrors is investigated. The losses in such resonator with the on-axis holes are low in compare with the case of spherical mirrors. The use of this type of optical resonator is briefly discussed.

  1. Fundamental modes in waveguide pipe twisted by saturated double-well potential

    Science.gov (United States)

    Chen, Gui-Hua; Wang, Hong-Cheng; Chen, Zhao-Pin; Liu, Yan

    2017-02-01

    We study fundamental modes trapped in a rotating ring with a saturated nonlinear double-well potential. This model, which is based on the nonlinear Schrödinger equation, can be constructed in a twisted waveguide pipe in terms of light propagation, or in a Bose-Einstein condensate (BEC) loaded into a toroidal trap under a combination of a rotating π-out-of-phase linear potential and nonlinear pseudopotential induced by means of a rotating optical field and the Feshbach resonance. Three types of fundamental modes are identified in this model, one symmetric and the other two asymmetric. The shape and stability of the modes and the transitions between different modes are investigated in the first rotational Brillouin zone. A similar model used a Kerr medium to build its nonlinear potential, but we replace it with a saturated nonlinear medium. The model exhibits not only symmetry breaking, but also symmetry recovery. A specific type of unstable asymmetric mode is also found, and the evolution of the unstable asymmetric mode features Josephson oscillation between two linear wells. By considering the model as a configuration of a BEC system, the ground state mode is identified among these three types, which characterize a specific distribution of the BEC atoms around the trap.

  2. A Demonstration of Underwater Bubble Capture by the Fundamental Acoustic Mode in Spherical Geometry

    Directory of Open Access Journals (Sweden)

    Umaporn KONTHARAK

    2008-01-01

    Full Text Available Nowadays, scientific demonstrations have become a crucial part of scientific learning. Acoustic waves are normally demonstrated in air via Kundt’s tube, but a physical demonstration for underwater acoustic waves is still lacking. In this paper, we address one of the aspects by demonstrating a way to acoustically-trap gas bubbles in a spherical, water-filled flask resonating at its first fundamental mode. The theory of acoustic waves in a spherical geometry, particularly the fundamental mode, is reviewed. The full description of the experimental setup is expressed both acoustically and electronically. By using this method, we show that a gas bubble can be stabilized in the middle of a flask at an acoustic frequency of 21.16 kHz, the acoustic fundamental frequency of the flask.

  3. Cold-Mode Accretion: Driving the Fundamental Mass-Metallicity Relation at z~2

    CERN Document Server

    Kacprzak, Glenn G; Glazebrook, Karl; Tran, Kim-Vy H; Yuan, Tiantian; Nanayakkara, Themiya; Allen, Rebecca J; Alcorn, Leo; Cowley, Michael; Labbe, Ivo; Spitler, Lee; Straatman, Caroline; Tomczak, Adam

    2016-01-01

    We investigate the star formation rate (SFR) dependence on the stellar mass and gas-phase metallicity relation at z=2 with MOSFIRE/Keck as part of the ZFIRE survey. We have identified 117 galaxies (1.98 10$~M$_{\\odot}$yr$^{-1}$) SFRs. At fixed mass, low star-forming galaxies tend to have higher metallicity than high star-forming galaxies. Using a few basic assumptions, we further show that the gas masses and metallicities required to produce the fundamental mass--metallicity relation, and its intrinsic scatter, are consistent with cold-mode accretion predictions obtained from the OWLS hydrodynamical simulations. Our results from both simulations and observations are suggestive that cold-mode accretion is responsible for the fundamental mass-metallicity relation at $z=2$ and demonstrates the direct relationship between cosmological accretion and the fundamental properties of galaxies.

  4. Influence of spherical aberrations on fundamental mode beam quality under different laser resonators

    Institute of Scientific and Technical Information of China (English)

    Xiang Zhen; Hu Miao; Ge Jian-Hong; Zhao Zhi-Gang; Wang Sha; Liu Chong; Chen Jun

    2009-01-01

    Spherical aberrations of the thermal lens of the active media are severe when solid state lasers are strongly pumped.The fundamental mode profile deteriorates due to the aberrations. Self-consistent modes of a resonator with aberrations are calculated by using the Fox-Li diffraction iterative algorithm. Calculation results show that the aberration induced fundamental mode beam quality deterioration depends greatly on the resonator design. The tolerance of a flat-flat resonator to the aberration coefficient is about 30λ in the middle of stability, where λ is the wavelength of laser beam. But for a dynamically stable resonator, 2λ of spherical aberration will create diffraction loss of more than 40%, if inappropriate design criteria are used. A birefringence compensated laser resonator with two Nd:YAG rods is experimentally studied. The experimental data are in quite good agreement with simulation results.

  5. Are there real orthogonal polarization modes in pulsar radio emission?

    Institute of Scientific and Technical Information of China (English)

    徐仁新; 乔国俊

    2000-01-01

    The orthogonal polarization modes (OPM) have been reported observationally and widely accepted by pulsar researchers. However, no acceptable theory can explain the origin of the OPM, which becomes a mystery in pulsar research field. Here a possible way to solve this mystery is pre-sented. We ask a question: Does there exist any real so-called OPM in pulsar radiation? It is proposed that the ’observed OPM’ in individual pulses could be the results of depolarization of pulsar radiation and the observational uncertainties originated f rom polarimeter in observation. A possible method to check this idea is suggested. If the idea is verified, the pulsar research would be influenced significant-ly in theory and in observation.

  6. Are there real orthogonal polarization modes in pulsar radio emission?

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The orthogonal polarization modes (OPM) have been reported observationally and widely accepted by pulsar researchers. However, no acceptable theory can explain the origin of the OPM, which becomes a mystery in pulsar research field. Here a possible way to solve this mystery is presented. We ask a question: Does there exist any real so-called OPM in pulsar radiation? It is proposed that the 'observed OPM' in individual pulses could be the results of depolarization of pulsar radiation and the observational uncertainties originated from polarimeter in observation. A possible method to check this idea is suggested. If the idea is verified, the pulsar research would be influenced significantly in theory and in observation.

  7. Numerical analysis of fundamental characteristics of superconducting magnetic bearings for a polarization modulator

    Science.gov (United States)

    Terachi, Yusuke; Terao, Yutaka; Ohsaki, Hiroyuki; Sakurai, Yuki; Matsumura, Tomotake; Sugai, Hajime; Utsunomiya, Shin; Kataza, Hirokazu; Yamamoto, Ryo

    2017-07-01

    We have carried out numerical analysis of mechanical properties of a superconducting magnetic bearing (SMB). A contactless bearing operating at below 10 K with low rotational energy loss is an attractive feature to be used as a rotational mechanism of a polarization modulator for a cosmic microwave background experiment. In such application, a rotor diameter of about 400 mm forces us to employ a segmented magnet. As a result, there is inevitable spatial gap between the segments. In order to understand the path towards the design optimizations, 2D and 3D FEM analyses were carried out to examine fundamental characteristics of the SMBs for a polarization modulator. Two axial flux type SMBs were dealt with in the analysis: (a) the SMB with axially magnetized permanent magnets (PMs), and (b) the SMB with radially magnetized PMs and steel components for magnetic flux paths. Magnetic flux lines and density distributions, electromagnetic force characteristics, spring constants, etc. were compared among some variations of the SMBs. From the numerical analysis results, it is discussed what type, configuration and design of SMBs are more suitable for a polarization modulator.

  8. Selective coupling of optical energy into the fundamental diffusion mode of a scattering medium

    CERN Document Server

    Ojambati, Oluwafemi S; Lagendijk, Ad; Mosk, Allard P; Vos, Willem L

    2015-01-01

    We demonstrate experimentally that optical wavefront shaping selectively couples light into the fundamental diffusion mode of a scattering medium. The total energy density inside a scattering medium of zinc oxide (ZnO) nanoparticles was probed by measuring the emitted fluorescent power of spheres that were randomly positioned inside the medium. The fluorescent power of an optimized incident wave front is observed to be enhanced compared to a non-optimized incident front. The observed enhancement increases with sample thickness. Based on diffusion theory, we derive a model wherein the distribution of energy density of wavefront-shaped light is described by the fundamental diffusion mode. The agreement between our model and the data is striking not in the least since there are no adjustable parameters. Enhanced total energy density is crucial to increase the efficiency of white LEDs, solar cells, and of random lasers, as well as to realize controlled illumination in biomedical optics.

  9. Entangling different degrees of freedom by quadrature squeezing cylindrically polarized modes

    DEFF Research Database (Denmark)

    Gabriel, C.; Aiello, A.; Zhong, W.

    2011-01-01

    for intense beams of light by exploiting the properties of cylindrically polarized modes. We show that already in a classical picture the spatial and polarization field variables of these modes cannot be factorized. Theoretically it is proven that by quadrature squeezing cylindrically polarized modes one...... generates entanglement between these two different degrees of freedom. Experimentally we demonstrate amplitude squeezing of an azimuthally polarized mode by exploiting the nonlinear Kerr effect in a specially tailored photonic crystal fiber. These results display that such novel continuous...

  10. General demonstration of principal states of polarization and real-time monitoring of polarization mode dispersion in optical fibres

    Institute of Scientific and Technical Information of China (English)

    Dong Hui; Wu Chong-Qing; Fu Song-Nian

    2004-01-01

    We investigated the general properties of polarization effects in optical fibres and demonstrated the existence of socalled principal states of polarization (PSP), which mean the fixed points in mathematics, in different polarization effects,such as birefringence and polarization mode dispersion, by using fixed point theory. Furthermore, a time evolution vector is defined to describe the time evolution of polarization state in optical fibres, which is used to investigate the time evolution of polarization mode dispersion vector (PDV), including differential group delay and PSP. The experimentalresults of real-time monitoring of PDV by using this method are reported. To our knowledge, this is the first report on monitoring PSP evolution in optical fibres.

  11. Polarization mode dispersion in optical fiber transmission systems

    Science.gov (United States)

    Cameron, John Charles

    The birefringence of optical fibers causes pulse broadening in fiber-optic communication systems. This phenomenon is known as polarization mode dispersion (PMD). PMD is one of the most important limiting factors for high capacity fiber-optic systems. A number of aspects of PMD are examined in this thesis. In Chapter 2 an expression is derived for the probability density function of the pulse broadening due to first-order PMD. This result is used to obtain an expression for the system limitation due to PMD. The birefringence of optical fibers is commonly simulated with the waveplate model. In Chapter 3 two standard versions of the waveplate model are introduced. In addition, a novel waveplate model is proposed. The characteristics of the three versions of the waveplate model are examined to confirm their suitability for use in subsequent chapters of the thesis. Simulations with the waveplate model are performed in Chapter 4 for three purposes: (1) to determine the impact of chromatic dispersion on the system limitation due to PMD, (2) to examine the effectiveness of three different PMD compensation techniques in the presence of chromatic dispersion, and (3) to examine the interaction of second-order chromatic dispersion with PMD. The simulations in Chapter 4 reveal that it is possible with one compensation technique to have output pulses that are narrower than the input pulses. In Chapter 5, this anomalous pulse narrowing is demonstrated analytically for a simple model of PMD and through experiment. It is also shown that this pulse narrowing can be explained as an interference phenomenon. Chapter 6 presents measurements of PMD and state of polarization on installed optical fibers. The PMD coefficients of 122 fibers are presented and the results are analyzed in terms of the age of the fibers and the type of cabling. Measurements of the time evolution of PMD and state of polarization are presented for fibers installed in both buried and aerial cables. The uncertainty

  12. CMB polarization anisotropies from cosmological reionization: extension to B-modes

    CERN Document Server

    Trombetti, Tiziana

    2012-01-01

    The accurate understanding of the ionization history of the Universe plays a fundamental role in modern cosmology. It includes a phase of cosmological reionization after the standard recombination epoch, possibly associated to the early stages of structure and star formation. While the simple "{\\tau}-parametrization" of the reionization process and, in particular, of its imprints on the CMB anisotropy likely represents a sufficiently accurate modelling for the interpretation of current CMB data, a great attention has been recently posed on the accurate computation of the reionization signatures in the CMB for a large variety of astrophysical scenarios and physical processes. This work is aimed at a careful characterization of the imprints introduced in the polarization anisotropy, with particular attention to the B-modes. We have implemented a modified version of CAMB, the Cosmological Boltzmann code for computing the angular power spectrum (APS) of the anisotropies of the CMB, to introduce the hydrogen and h...

  13. Second-order polarization-mode dispersion in photonic crystal fibers

    DEFF Research Database (Denmark)

    Larsen, T; Bjarklev, Anders Overgaard; Peterson, A

    2003-01-01

    We report the first experimental measurements of second-order polarization-mode dispersion in two successive 900 meter pulls of a silica photonic crystal fiber.......We report the first experimental measurements of second-order polarization-mode dispersion in two successive 900 meter pulls of a silica photonic crystal fiber....

  14. C-band fundamental/first-order mode converter based on multimode interference coupler on InP substrate

    Science.gov (United States)

    Limeng, Zhang; Dan, Lu; Zhaosong, Li; Biwei, Pan; Lingjuan, Zhao

    2016-12-01

    The design, fabrication and characterization of a fundamental/first-order mode converter based on multimode interference coupler on InP substrate were reported. Detailed optimization of the device parameters were investigated using 3D beam propagation method. In the experiments, the fabricated mode converter realized mode conversion from the fundamental mode to the first-order mode in the wavelength range of 1530-1565 nm with excess loss less than 3 dB. Moreover, LP01 and LP11 fiber modes were successfully excited from a few-mode fiber by using the device. This InP-based mode converter can be a possible candidate for integrated transceivers for future mode-division multiplexing system. Project supported by the National Basic Research Program of China (No. 2014CB340102) and in part by the National Natural Science Foundation of China (Nos. 61274045, 61335009).

  15. Wavelength Dependence of the Polarization Singularities in a Two-Mode Optical Fiber

    Directory of Open Access Journals (Sweden)

    V. V. G. Krishna Inavalli

    2012-01-01

    Full Text Available We present here an experimental demonstration of the wavelength dependence of the polarization singularities due to linear combination of the vector modes excited directly in a two-mode optical fiber. The coherent superposition of the vector modes excited by linearly polarized Gaussian beam as offset skew rays propagated in a helical path inside the fiber results in the generation of phase singular beams with edge dislocation in the fiber output. The polarization character of these beams is found to change dramatically with wavelength—from left-handed elliptically polarized edge dislocation to right-handed elliptically polarized edge-dislocation through disclinations. The measured behaviour is understood as being due to intermodal dispersion of the polarization corrections to the propagating vector modes, as the wavelength of the input beam is scanned.

  16. Density functional theory study of vibrational spectra, and assignment of fundamental modes of dacarbazine

    Indian Academy of Sciences (India)

    S Gunasekaran; S Kumaresan; R Arunbalaji; G Anand; S Srinivasan

    2008-05-01

    The FTIR and FT Raman spectra of dacarbazine were recorded in the regions 4000-400 and 3500-100 cm-1, respectively. The optimized geometry, wavenumber, polarizability and several thermodynamic properties of dacarbazine were studied using ab initio Hartree-Fock, MP2 and DFT methods. A complete vibrational assignment aided by the theoretical harmonic wavenumber analysis was proposed. The calculated harmonic vibrational frequencies were compared with experimental FTIR and FT Raman spectra. Based on the comparison between calculated and experimental results and the comparison with related molecules, assignments of fundamental vibrational modes were made. The X-ray geometry and experimental frequencies were compared with the results of theoretical calculations.

  17. Fundamental-Mode Oscillations of Two Coronal Loops within a Solar Magnetic Arcade

    CERN Document Server

    Jain, Rekha; Hindman, B W

    2015-01-01

    We analyse intensity variations, as measured by the Atmospheric Imaging Assembly (AIA) in the 171 {\\AA} passband, in two coronal loops embedded within a single coronal magnetic arcade. We detect oscillations in the fundamental mode with periods of roughly 2 minutes and decay times of 5 minutes. The oscillations were initiated by interaction of the arcade with a large wavefront issuing from a flare site. Further, the power spectra of the oscillations evince signatures consistent with oblique propagation to the field lines and for the existence of a 2-D waveguide instead of a 1-D one.

  18. Novel planar Gunn diode operating in fundamental mode up to 158 GHz

    Energy Technology Data Exchange (ETDEWEB)

    Li Chong; Khalid, A; Holland, M C; Cumming, D S R [Department of Electronic and Electrical Engineering, University of Glasgow, Glasgow G12 8LT (United Kingdom); Pilgrim, N; Dunn, G, E-mail: lichong@elec.gla.ac.u [School of Engineering and Physical Sciences, University of Aberdeen, Aberdeen AB24 SFX (United Kingdom)

    2009-11-15

    We show the experimental realisation of fundamental mode operation of planar Gunn diode structures fabricated in GaAs/AlGaAs quantum wells. The electron density in the active channel is enhanced by positioning double delta-doping layers on either side. Small signal measurement shows that a typical device exhibits negative resistance up to 158 GHz. Using this device structure we have demonstrated a planar Gunn oscillator working at 115.5 GHz with an output power of -28 dBm.

  19. Novel planar Gunn diode operating in fundamental mode up to 158 GHz

    Science.gov (United States)

    Li, Chong; Khalid, A.; Pilgrim, N.; Holland, M. C.; Dunn, G.; Cumming, D. S. R.

    2009-11-01

    We show the experimental realisation of fundamental mode operation of planar Gunn diode structures fabricated in GaAs/AlGaAs quantum wells. The electron density in the active channel is enhanced by positioning double delta-doping layers on either side. Small signal measurement shows that a typical device exhibits negative resistance up to 158 GHz. Using this device structure we have demonstrated a planar Gunn oscillator working at 115.5 GHz with an output power of -28 dBm.

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

    Institute of Scientific and Technical Information of China (English)

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

    2013-01-01

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

  1. A tunable comb filter using single-mode/multimode/polarization-maintaining-fiber-based Sagnac fiber loop

    Institute of Scientific and Technical Information of China (English)

    Ruan Juan; Zhang Wei-Gang; Zhang Hao; Geng Peng-Cheng; Bai Zhi-Yong

    2013-01-01

    A novel tunable comb filter composed of a single-mode/multimode/polarization-maintaining-fiber-based Sagnac fiber loop is proposed and experimentally demonstrated.The filter tunability is achieved by rotating the polarization controller.The spectral shift is dependent on rotation direction and the position of the polarization controller.In addition,the adjustable range achieved by rotating the half-wave-plate polarization controller is twice higher than that of the quarter-wave-plate one.

  2. Pulse bundles and passive harmonic mode-locked pulses in Tm-doped fiber laser based on nonlinear polarization rotation.

    Science.gov (United States)

    Wang, Xiong; Zhou, Pu; Wang, Xiaolin; Xiao, Hu; Liu, Zejin

    2014-03-10

    We demonstrate the nanosecond-level pulses in Tm-doped fiber laser generated by passively harmonic mode-locking. Nonlinear polarization rotation performed by two polarization controllers (PCs) is employed to induce the self-starting harmonic mode-locking. The fundamental repetition rate of the laser is 448.8 kHz, decided by the length of the cavity. Bundles of pulses with up to 17 uniform subpulses are generated due to the split of pulse when the pump power increases and the PCs are adjusted. Continuous harmonic mode-locked pulse trains are obtained with 1st to 6th and even more than 15th order when the positions of the PCs are properly fixed and the pump power is scaled up. The widths of all the uniform individual pulses are mostly 3-5 ns, and pulse with width of 304 ns at fundamental repetition rate can also be generated by adjusting the PCs. Hysteresis phenomenon of the passively harmonic mode-locked pulses' repetition frequency versus pump power is observed. The rather wide 3dB spectral bandwidth of the pulse train (25 nm) indicates that they may resemble noise-like pulses.

  3. Enhanced efficiency of a continuous-wave mode-locked Nd:YAG laser by compensation of the thermally induced, polarization-dependent bifocal lens.

    Science.gov (United States)

    Wetter, N U; Maldonado, E P; Vieira, N D

    1993-09-20

    Measurements of the bifocal, thermally induced lenses of a cw Nd:YAG laser were obtained. We observed four different focal lengths that are polarization and direction dependent. The focal lengths were used to design stable resonators with large fundamental mode filling in the laser gain medium. The beam is totally polarized in the desired direction even without an intracavity Brewster window. We developed a general approach for the optimization of single-lamp, cw-pumped Nd:YAG lasers. Up to 22 W of cw output power in the vertically polarized TEM(00) mode and 15 W in the horizontal polarization are obtained for moderate lamp currents. Also, we demonstrate mode locking with 56-ps pulse duration at 33 A of lamp current and up to 13 W of average output power.

  4. Mode characteristics of hollow core Bragg fiber

    Institute of Scientific and Technical Information of China (English)

    Minning Ji; Zhidong Shi; Qiang Guo

    2005-01-01

    Analytical expression to calculate propagation constant and mode field of the hollow core Bragg fiber is derived. Numerical results are presented. It is shown that the fundamental mode of the hollow core Bragg fiber is circularly symmetric TE01 mode with no polarization degeneracy, while the higher order mode may be HE11, TM01, or TE02 etc.. This property is different from conventional optical fiber that its fundamental mode is the linearly polarized HE11 mode and is polarization degeneracy.

  5. Ultraviolet Continuum Generation in the Fundamental Mode of Photonic Crystal Fibers

    Institute of Scientific and Technical Information of China (English)

    HAN Ying; HOU Lan-Tian; YUAN Jin-Hui; XIA Chang-Ming; ZHOU Gui-Yao

    2012-01-01

    The ultraviolet continuum generation in the fundamental mode of photonic crystal fibers designed and fabricated in our lab are experimentally demonstrated.When the pump works in the normal dispersion regions of 780 nm and 830 nm,and the average powers increase from 100 to 500 m W,anti-Stokes signals can be efficiently generated based on the phase-matched degenerate four-wave mixing.The cross-phase modulation between the pump and the generated anti-Stokes signals can effectively extend the continuum into the ultraviolet wavelength range.This can provide an efficient light source for ultraviolet photonics and spectroscopy.%The ultraviolet continuum generation in the fundamental mode of photonic crystal fibers designed and fabricated in our lab are experimentally demonstrated. When the pump works in the normal dispersion regions of 780 did and 830 nm, and the average powers increase from 100 to 500 Mw, anti-Stokes signals can be efficiently generated based on the phase-matched degenerate four-wave mixing. The cross-phase modulation between the pump and the generated anti-Stokes signals can effectively extend the continuum into the ultraviolet wavelength range. This can provide an efficient light source for ultraviolet photonics and spectroscopy.

  6. OGLE-ing the Magellanic System: Photometric Metallicity from Fundamental Mode RR Lyrae Stars

    CERN Document Server

    Skowron, D M; Udalski, A; Szymański, M K; Pietrukowicz, P; Poleski, R; Wyrzykowski, Ł; Ulaczyk, K; Kozłowski, S; Skowron, J; Mróz, P; Pawlak, M

    2016-01-01

    In an era of extensive photometric observations, the catalogs of RR Lyrae type variable stars number tens of thousands of objects. The relation between the iron abundance [Fe/H] and the Fourier parameters of the stars light curve allows us to investigate mean metallicities and metallicity gradients in various stellar environments, independently of time-consuming spectroscopic observations. In this paper we use almost 15000 V- and I-band light curves of fundamental mode RR Lyrae stars from the OGLE-IV survey to provide a precise relation between the V- and I-band phase parameter phi_31 used to estimate [Fe/H]. We apply this relation to metallicity formulae developed for the Johnson V- and the Kepler Kp-band to obtain the relation between [Fe/H] and phi_31 for the I-band photometry. Last, we apply the new relation of Nemec et al. (2013) to the OGLE-IV fundamental mode RR Lyrae stars data and construct a metallicity map of the Magellanic Clouds. Median [Fe/H] is -1.39 +- 0.44 dex for the LMC and -1.77 +- 0.48 de...

  7. Detection of North Atlantic Polar Lows in Climate Mode Simulations

    Science.gov (United States)

    Zahn, M.; von Storch, H.; Bakan, S.

    2007-12-01

    Polar lows are not properly resolved in global re-analyses. Atmospheric limited area models (LAMs), which post- process re-analysis data, may be an appropriate tool for describing the year-to-year variability and decadal trends in the formation of Polar Lows. The merits and potential of this approach are examined in case studies of reproducing polar low occurrences with a LAM. A series of three week long ensemble simulations of weather situations over the NE Atlantic with a RCM/LAM (CLM) was conducted and its capability to reproduce polar lows was investigated. To keep the influence of the initial field low, the simulations were begun approximately two weeks prior to the polar low formation. It is shown that polar lows can be reproduced with the LAM. When "spectral nudging" is applied a polar low develops in all ensemble members and the simulations are very insensitive to the initial conditions. However there are differences in detail compared to observational data, e.g extent of pressure decline and polar low's location. In a scond step towards our goal of determining trends in changing frequencies and characteristics, an algorithm for automatical detection polar lows has been designed and tested. This algorithm was applied to the output fields of a long-term simulation and first results are shown.

  8. Coupling of light into the fundamental diffusion mode of a scattering medium (Conference Presentation)

    Science.gov (United States)

    Ojambati, Oluwafemi S.; Yılmaz, Hasan; Lagendijk, Ad; Mosk, Allard P.; Vos, Willem L.

    2016-03-01

    Diffusion equation describes the energy density inside a scattering medium such as biological tissues and paint [1]. The solution of the diffusion equation is a sum over a complete set of eigensolutions that shows a characteristic linear decrease with depth in the medium. It is of particular interest if one could launch energy in the fundamental eigensolution, as this opens the opportunity to achieve a much greater internal energy density. For applications in optics, an enhanced energy density is vital for solid-state lighting, light harvesting in solar cells, low-threshold random lasers, and biomedical optics. Here we demonstrate the first ever selective coupling of optical energy into a diffusion eigensolution of a scattering medium of zinc oxide (ZnO) paint. To this end, we exploit wavefront shaping to selectively couple energy into the fundamental diffusion mode, employing fluorescence of nanoparticles randomly positioned inside the medium as a probe of the energy density. We observe an enhanced fluorescence in case of optimized incident wavefronts, and the enhancement increases with sample thickness, a typical mesoscopic control parameter. We interpret successfully our result by invoking the fundamental eigensolution of the diffusion equation, and we obtain excellent agreement with our observations, even in absence of adjustable parameters [2]. References [1] R. Pierrat, P. Ambichl, S. Gigan, A. Haber, R. Carminati, and R. Rotter, Proc. Natl. Acad. Sci. U.S.A. 111, 17765 (2014). [2] O. S. Ojambati, H. Yilmaz, A. Lagendijk, A. P. Mosk, and W. L. Vos, arXiv:1505.08103.

  9. Observation on fundamental and second harmonic mode ECRH assisted plasma startup in SST-1 experiments

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Kirit, E-mail: kirit33@gmail.com; Pradhan, Subrata

    2016-05-15

    In SST-1, successful plasma startup has been achieved at very low loop voltage with the help of ECRH pre-ionization. ECRH is operated in both O mode and X mode for the purpose of pre-ionization at the pre fill pressure of 1 × 10{sup −5} mbar. A delay in breakdown has been observed in case of second harmonic ECRH pre-ionization; where in case of fundamental mode of ECRH pre-ionization, the instant breakdown has been observed. This work has attempted at explaining the non-linear interaction of the seed electrons with the electromagnetic field of the incident ECRH wave that has led to break down of the plasma. The delay in the break down attributes to the time differential between the applications of the ECRH pulse to that of the appearance of the H-alpha signal in SST-1. The observed experimental results have been discussed in this paper from the first principles and numerically solving the electron-ECRH field interactions resulting in energy gains of the electrons leading to plasma break down in SST-1 specific discharge conditions.

  10. Polarization-dependent properties of the cladding modes of a single mode fiber covered with gold nanoparticles.

    Science.gov (United States)

    Zhou, Wenjun; Mandia, David J; Griffiths, Matthew B E; Bialiayeu, Aliaksandr; Zhang, Yang; Gordon, Peter G; Barry, Seán T; Albert, Jacques

    2013-01-14

    The properties of the high order cladding modes of standard optical fibers are measured in real-time during the deposition of gold nanoparticle layers by chemical vapor deposition (CVD). Using a tilted fiber Bragg grating (TFBG), the resonance wavelength and peak-to-peak amplitude of a radially polarized cladding mode resonance located 51 nm away from the core mode reflection resonance shift by 0.17 nm and 13.54 dB respectively during the formation of a ~200 nm thick layer. For the spectrally adjacent azimuthally polarized resonance, the corresponding shifts are 0.45 nm and 16.34 dB. In both cases, the amplitudes of the resonance go through a pronounced minimum of about 5 dB for thickness between 80 and 100 nm and at the same time the wavelengths shift discontinuously. These effects are discussed in terms of the evolving metallic boundary conditions perceived by the cladding modes as the nanoparticles grow. Scanning Electron Micrographs and observations of cladding mode light scattering by nanoparticle layers of various thicknesses reveal a strong correlation between the TFBG polarized transmission spectra, the grain size and fill factor of the nanoparticles, and the scattering efficiency. This allows the preparation of gold nanoparticle layers that strongly discriminate between radially and azimuthally polarized cladding mode evanescent fields, with important consequences in the plasmonic properties of these layers.

  11. Electronic control of nonlinear-polarization-rotation mode locking in Yb-doped fiber lasers.

    Science.gov (United States)

    Shen, Xuling; Li, Wenxue; Yan, Ming; Zeng, Heping

    2012-08-15

    We demonstrate a convenient approach to precisely tune the polarization state of a nonlinear-polarization-rotation mode-locked Yb-doped fiber laser by using an electronic polarization controller. It is shown to benefit self-starting of mode-locking states, with precise tuning of the spectral profile, pulse width, and carrier-envelope offset frequency. The pulse width changed linearly by 0.78 ps in the time domain, and the carrier-envelope offset frequency shifted ~77.5 MHz in the frequency domain with a slight change of the driving voltage of 30.7 mV applied on the controller, corresponding to a polarization rotation of 0.0135π. This facilitated precise and automatic regeneration of a particular mode-locking state by setting an accurate voltage at the polarization controller with a programmed microprocessor control unit.

  12. Fundamental modes of new dispersive SH-waves in piezoelectromagnetic plate

    Indian Academy of Sciences (India)

    A A Zakharenko

    2013-11-01

    Fundamental modes of new dispersive shear-horizontal (SH) acoustic waves propagating in the (6 mm) piezoelectromagnetic plate are studied. These SH-waves can propagate when the following boundary conditions are exploited for both the upper and lower surfaces of the plate: (1) when the surfaces are mechanically free, electrically and magnetically closed and (2) when the surfaces are mechanically free, electrically and magnetically open. The SH-waves depend on the electromagnetic wave speed $V_{\\text{EM}} = 1/\\sqrt{( )}$ and can only exist when the electromagnetic constant ≠ 0. The calculations (first evidence) were performed for the PZT-5H–Terfenol-D which is a composite with a large value of . The limit cases of large values of (2 = 0.5 , 2 = 0.9 ), and 2 = 0.99 ) are studied because they satisfy the limitation condition of 2 < .

  13. Spontaneous nucleation and growth of GaN nanowires: the fundamental role of crystal polarity.

    Science.gov (United States)

    Fernández-Garrido, Sergio; Kong, Xiang; Gotschke, Tobias; Calarco, Raffaella; Geelhaar, Lutz; Trampert, Achim; Brandt, Oliver

    2012-12-12

    We experimentally investigate whether crystal polarity affects the growth of GaN nanowires in plasma-assisted molecular beam epitaxy and whether their formation has to be induced by defects. For this purpose, we prepare smooth and coherently strained AlN layers on 6H-SiC(0001) and SiC(0001̅) substrates to ensure a well-defined polarity and an absence of structural and morphological defects. On N-polar AlN, a homogeneous and dense N-polar GaN nanowire array forms, evidencing that GaN nanowires form spontaneously in the absence of defects. On Al-polar AlN, we do not observe the formation of Ga-polar GaN NWs. Instead, sparse N-polar GaN nanowires grow embedded in a Ga-polar GaN layer. These N-polar GaN nanowires are shown to be accidental in that the necessary polarity inversion is induced by the formation of Si(x)N. The present findings thus demonstrate that spontaneously formed GaN nanowires are irrevocably N-polar. Due to the strong impact of the polarity on the properties of GaN-based devices, these results are not only essential to understand the spontaneous formation of GaN nanowires but also of high technological relevance.

  14. Molecular electronegativity in density functional theory(Ⅷ) Charge polarization modes in a closed system

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on the density functional theory and the atom-bond electronegativity equalization model (ABEEM), a method is proposed to construct the softness matrix and to obtain the electron population normal modes (PNMs) for a closed system. Using this method the information about the bond charge polarization in a molecule can be obtained easily. The test calculation shows that the PNM obtained by this method includes all the modes about the bond charge polarization explicitly. And the bond charge polarization mode characterized by the biggest eigenvalue, which is the softest one of all modes related with chemical bonds, can describe the charge polarization process in a molecule as exquisitely as the corresponding ab initio method.

  15. OGLE-ing the Magellanic System: Photometric Metallicity from Fundamental Mode RR Lyrae Stars

    Science.gov (United States)

    Skowron, D. M.; Soszyński, I.; Udalski, A.; Szymański, M. K.; Pietrukowicz, P.; Skowron, J.; Poleski, R.; Wyrzykowski, Ł.; Ulaczyk, K.; Kozłowski, S.; Mróz, P.; Pawlak, M.

    2016-09-01

    In an era of extensive photometric observations, the catalogs of RR Lyr type variable stars number tens of thousands of objects. The relation between the iron abundance [Fe/H] and the Fourier parameters of the stars light curve allows us to investigate mean metallicities and metallicity gradients in various stellar environments, independently of time-consuming spectroscopic observations. In this paper we use almost 6500 V- and I-band light curves of fundamental mode RR Lyr stars from the OGLE-IV survey to provide a relation between the V- and I-band phase parameter ϕ31 used to estimate [Fe/H]. The relation depends on metallicity, which limits its applicability. We apply this relation to metallicity formulae developed for the Johnson V- and the Kepler Kp-band to obtain the relation between [Fe/H] and ϕ31 for the I-band photometry. Last, we apply the new relation of Nemec to the OGLE-IV fundamental mode RR Lyr stars data and construct a metallicity map of the Magellanic Clouds. Median [Fe/H] is -1.39±0.44 dex for the LMC and -1.77±0.48 dex for the SMC, on the Jurcsik metallicity scale. We also find a metallicity gradient within the LMC with a slope of -0.029±0.002 dex/kpc in the inner 5 kpc and -0.030±0.003 dex/kpc beyond 8 kpc, and no gradient in-between (-0.019±0.002 dex/kpc integrally). We do not observe a metallicity gradient in the SMC, although we show that the metal-rich RRab stars are more concentrated toward the SMC center than the metal-poor.

  16. Evaluation of polarization mode dispersion in a telecommunication wavelength selective switch using quantum interferometry.

    Science.gov (United States)

    Fraine, A; Minaeva, O; Simon, D S; Egorov, R; Sergienko, A V

    2012-01-30

    A polarization mode dispersion (PMD) measurement of a commercial telecommunication wavelength selective switch (WSS) using a quantum interferometric technique with polarization-entangled states is presented. Polarization-entangled photons with a broad spectral width covering the telecom band are produced using a chirped periodically poled nonlinear crystal. The first demonstration of a quantum metrology application using an industrial commercial device shows a promising future for practical high-resolution quantum interference.

  17. Tuning the transmission lineshape of a photonic crystal slab guided-resonance mode by polarization control.

    Science.gov (United States)

    Huang, Ningfeng; Martínez, Luis Javier; Povinelli, Michelle L

    2013-09-09

    We demonstrate a system consisting of a two-dimensional photonic crystal slab and two polarizers which has a tunable transmission lineshape. The lineshape can be tuned from a symmetric Lorentzian to a highly asymmetric Fano lineshape by rotating the output polarizer. We use temporal coupled mode theory to explain the measurement results. The theory also predicts tunable phase shift and group delay.

  18. Passive mode locking of lasers by crossed-polarization gain modulation.

    Science.gov (United States)

    Javaloyes, Julien; Mulet, Josep; Balle, Salvador

    2006-10-20

    We report on a novel approach for inducing passive mode locking of lasers without using any saturable absorber but exploiting the polarization degree of freedom of light. In our scheme, passive mode locking is achieved by crossed-polarization gain modulation caused by the reinjection of a polarization-rotated replica of the laser output after a time delay. The reinjection time delay defines resonance tongues that correspond to mode-locking operation. Numerical continuation reveals that the cw solution is destabilized through a Hopf bifurcation that defines the onset of multimode operation which evolves sharply into a mode-locked solution. Our approach can be applied to a large variety of laser systems. For vertical-cavity surface-emitting lasers, we demonstrate stable mode-locked pulses at repetition rates in the GHz range and pulse widths of few tens of picoseconds.

  19. Characterization of a self-starting, passively mode-locked fiber ring laser that exploits nonlinear polarization evolution.

    Science.gov (United States)

    Matsas, V J; Richardson, D J; Newson, T P; Payne, D N

    1993-03-01

    A full characterization of a self-starting, passively mode-locked soliton ring fiber laser in terms of its various modes of mode-locked operation, cavity length, and type of fiber used is presented. Direct evidence, based on state-of-polarization measurements, that nonlinear polarization evolution is the responsible mode-locking mechanism is also given.

  20. Revealing Fundamental Interactions: the Role of Polarized Positrons and Electrons at the Linear Collider

    Energy Technology Data Exchange (ETDEWEB)

    Moortgat-Pick, G.; /CERN /Durham U., IPPP; Abe, T.; Alexander, G.; Ananthanarayan, B.; Babich, A.A.; Bharadwaj, V.; Barber, D.; Bartl, A.; Brachmann, A.; Chen, S.; Clarke,; Clendenin, J.E.; Dainton, J.; Desch, K.; Diehl, M.; Dobos, B.; Dorland, T.; Eberl, H.; Ellis, John R.; Flottman, K.; Frass, H.; /CERN /Durham U., IPPP /Colorado U. /Tel-Aviv

    2005-07-06

    The proposed International Linear Collider (ILC) is well-suited for discovering physics beyond the Standard Model and for precisely unraveling the structure of the underlying physics. The physics return can be maximized by the use of polarized beams. This report shows the paramount role of polarized beams and summarizes the benefits obtained from polarizing the positron beam, as well as the electron beam. The physics case for this option is illustrated explicitly by analyzing reference reactions in different physics scenarios. The results show that positron polarization, combined with the clean experimental environment provided by the linear collider, allows to improve strongly the potential of searches for new particles and the identification of their dynamics, which opens the road to resolve shortcomings of the Standard Model. The report also presents an overview of possible designs for polarizing both beams at the ILC, as well as for measuring their polarization.

  1. The Role of polarized positrons and electrons in revealing fundamental interactions at the linear collider

    Energy Technology Data Exchange (ETDEWEB)

    Moortgat-Pick, G.; /CERN /Durham U., IPPP; Abe, T.; Alexander, G.; Ananthanarayan, B.; Babich, A.A.; Bharadwaj, V.; Barber, D.; Bartl, A.; Brachmann, A.; Chen, S.; Clarke,; Clendenin, J.E.; Dainton, J.; Desch, K.; Diehl, M.; Dobos, B.; Dorland, T.; Eberl, H.; Ellis, John R.; Flottman, K.; Frass, H.; /CERN /Durham U., IPPP /Colorado U. /Tel-Aviv

    2005-07-01

    The proposed International Linear Collider (ILC) is well-suited for discovering physics beyond the Standard Model and for precisely unraveling the structure of the underlying physics. The physics return can be maximized by the use of polarized beams. This report shows the paramount role of polarized beams and summarizes the benefits obtained from polarizing the positron beam, as well as the electron beam. The physics case for this option is illustrated explicitly by analyzing reference reactions in different physics scenarios. The results show that positron polarization, combined with the clean experimental environment provided by the linear collider, allows to improve strongly the potential of searches for new particles and the identification of their dynamics, which opens the road to resolve shortcomings of the Standard Model. The report also presents an overview of possible designs for polarizing both beams at the ILC, as well as for measuring their polarization.

  2. Shotgun lipidomics on a LTQ Orbitrap mass spectrometer by successive switching between acquisition polarity modes

    DEFF Research Database (Denmark)

    Schuhmann, K.; Almeida, R.; Baumert, M.

    2012-01-01

    polarity, and therefore it is beneficial to analyze lipid mixtures in both positive and negative modes. Hybrid LTQ Orbitrap mass spectrometers are widely applied in topdown lipidomics; however, rapid polarity switching was previously unfeasible because of the severe and immediate degradation of mass...... accuracy. Here, we report on a method to rapidly acquire high-resolution spectra in both polarity modes with sub-ppm mass accuracy and demonstrate that it not only simplifies and accelerates shotgun lipidomics analyses but also improves the lipidome coverage because more lipid classes and more individual...

  3. Perceptual space induced by cochlear implant all-polar stimulation mode

    DEFF Research Database (Denmark)

    Marozeau, Jeremy; Mckay, Colette M.

    2015-01-01

    It has often been argued that a main limitation of the cochlear implant is the spread of current induced by each electrode, which activates an inappropriately large range of sensory neurons. In order to reduce this spread, a new stimulation mode, the all-polar mode, was tested with 5 participants...

  4. A novel relativistic magnetron with circularly polarized TE11 coaxial waveguide mode

    Science.gov (United States)

    Shi, Di-Fu; Qian, Bao-Liang; Wang, Hong-Gang; Li, Wei; Du, Guang-Xing

    2016-11-01

    A novel relativistic magnetron (RM) with a circularly polarized TE11 coaxial waveguide mode and its corresponding mode excitation are investigated in this paper. By operating in the 4π/5 mode in the ten-cavity RM and compactly designing the RM structure with the all cavity-magnetron axial extraction technique, the RM can directly output a circularly polarized TE11 coaxial waveguide mode in a reversible direction of rotation without any mode converters. In addition, the analysis of mode excitation can be generalized to a 2N-cavity RM, where 2N  >  4 is the number of cavities. Results of the 3D particle-in-cell (PIC) simulation show that a high power microwave (HPM) with an operating frequency of 4.15 GHz and an output power of 700 MW is obtained from the RM, corresponding to the power conversion efficiency of 50.0%.

  5. Magneto-optic Crystal Polarization Controller Assisted Mode-Locked Fiber Laser

    Institute of Scientific and Technical Information of China (English)

    ZHAO Guang-Zhen; GUI Li-Li; XIAO Xiao-Sheng; YANG Chang-Xi

    2011-01-01

    We report a passively mode-locked erbium-doped fiber laser based on a compact magneto-optic crystal polarization controller. The length of the polarization controller consisting of four magneto-optic crystal rotators and two quarter wave-plates is only 10cm.Adjusting the polarization controller, central wavelength around 1559nm and repetition rate 21.10 MHz mode-locked pulse are obtained. Pulse duration and 3 dB spectrum width are 598.4fs and 6.24nm respectively. Single pulse energy is about 151.7pJ. Because of its small size, low insertion loss,good controllability and negligible dispersion, the magneto-optic crystal polarization controller could be an ideal polarization controller in fiber lasers.

  6. Excitation of radiationless anapole mode of isotropic dielectric nanoparticles with tightly focused radially polarized beam

    CERN Document Server

    Wei, Lei; Bhattacharya, Nandini; Urbach, H Paul

    2016-01-01

    A high index dielectric nano-sphere can be excited and yet remain radiationless. A method to excite the non-radiating anapole mode of a high index isotropic dielectric nanosphere is presented. With tightly focused radially polarized beam illumination, the main-contributing electric dipole mode and magnetic modes can be zero with only a weak electric quadruple contributing to the total scattering. Further, with a standing wave illumination formed by two counter-propagating focused radially polarized beam under $4\\pi$ configuration, the ideal radiationless ananpole can be excited.

  7. Theoretical Design of Single-Polarization Single- Mode Microstructured Polymer Optical Fibres

    Institute of Scientific and Technical Information of China (English)

    REN Li-Yong; WANG Han-Yi; ZHANG Ya-Ni; YAO Bao-Li; ZHAO Wei

    2007-01-01

    Using the full-vector plane-wave expansion method, a kind of PMMA-based polarization-maintaining microstructured optical fibre (PM-mPOF) is theoretically studied. Dependence of the cutoff wavelengths of the two orthogonal polarization states (polarized along the two principal axes of PM-mPOF) on the structure parameters of the fibre is investigated in detail. A single-polarization single-mode (SPSM) PM-mPOF working in the visible region is designed and optimized with the result of the maximum SPSM bandwidth of 140 nm.

  8. Mode decoupling in solid state ring laser based on stimulated Raman effect in polar crystals

    Institute of Scientific and Technical Information of China (English)

    Luo Zhang; Yuan Xiao-Dong; Ye Wei-Min; Zeng Chun; Ji Jia-Rong

    2011-01-01

    In this paper we study the gain saturation induced mode-coupling control in solid state ring laser devices based on the stimulated Raman effect of the polar crystals in order to realize solid state ring laser gyroscopes. We theoretically investigate the mode coupling induced by gain saturation between clockwise (CW) and counterclockwise (CCW) propagating laser modes. Because the CW and CCW running waves are pumped with counter-propagating lasers respectively, the independent coexistence can be ensured.

  9. The Music of the Aetherwave - B-mode Polarization in Einstein-Aether Theory

    CERN Document Server

    Nakashima, Masahiro

    2011-01-01

    We study how the dynamical vector degree of freedom in modified gravity affects the CMB B-mode polarization in terms of the Einstein-aether theory. In this theory, vector perturbations can be generated from inflation, which can grow on superhorizon scales in the subsequent epochs and thereby leaves imprints on the CMB B-mode polarization. We derive the linear perturbation equations in a covariant formalism, and compute the CMB B-mode polarization using the CAMB code modified so as to incorporate the effect of the aether vector field. We find that the amplitude of the B-mode signal from the aether field can surpass the contribution from the inflationary gravitational waves for a viable range of model parameters. We also give an analytic argument explaining the shape of the spectrum based on the tight coupling approximation.

  10. Excess B-modes extracted from the Planck polarization maps

    CERN Document Server

    Nørgaard-Nielsen, H U

    2016-01-01

    One of the main obstacles for extracting the Cosmic Microwave Background (CMB) from mm/submm observations is the pollution from the main Galactic components: synchrotron, free-free and thermal dust emission. The feasibility of using simple neural networks to extract CMB has been demonstrated on both temperature and polarization data obtained by the WMAP satellite. The main goal of this paper is to demonstrate the feasibility of neural networks for extracting the CMB signal from the Planck polarization data with high precision. Both auto-correlation and cross-correlation power spectra within a mask covering about 63 percent of the sky have been used together with a 'high pass filter' in order to minimize the influence of the remaining systematic errors in the Planck Q and U maps. Using the Planck 2015 released polarization maps, a BB power spectrum have been extracted by \\textit{Multilayer Perceptron} neural networks. This spectrum contains a bright feature with signal to noise ratios $\\simeq$ 4.5 within 200 $...

  11. Excess B‐modes extracted from the Planck polarization maps

    DEFF Research Database (Denmark)

    Nørgaard-Nielsen, Hans Ulrik

    2016-01-01

    One of the main obstacles for extracting the Cosmic Microwave Background (CMB) from mm/submm observations is the pollution from the main Galactic components: synchrotron, free‐free and thermal dust emission. The feasibility of using simple neural networks to extract CMB has been demonstrated on b...... tensor to scalar ratios). The feasibility of the neural network to remove the residual systematics from the available Planck polarization data to a high level has been demonstrated. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)......One of the main obstacles for extracting the Cosmic Microwave Background (CMB) from mm/submm observations is the pollution from the main Galactic components: synchrotron, free‐free and thermal dust emission. The feasibility of using simple neural networks to extract CMB has been demonstrated...... on both temperature and polarization data obtained by the WMAP satellite. The main goal of this paper is to demonstrate the feasibility of neural networks for extracting the CMB signal from the Planck polarization data with high precision. Both auto‐correlation and cross‐correlation power spectra within...

  12. Dipole modulation in tensor modes: signatures in CMB polarization

    Energy Technology Data Exchange (ETDEWEB)

    Zarei, Moslem [Isfahan University of Technology, Department of Physics, Isfahan (Iran, Islamic Republic of); Institute for Research in Fundamental Sciences (IPM), School of Astronomy, P. O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

    2015-06-15

    In this work we consider a dipole asymmetry in tensor modes and study the effects of this asymmetry on the angular power spectra of CMB. We derive analytical expressions for the C{sub l}{sup TT} and C{sub l}{sup BB} in the presence of such dipole modulation in tensor modes for l < 100. We also discuss on the amplitude of modulation term and show that the C{sub l}{sup BB} is considerably modified due to this term. (orig.) 3.

  13. Litmus Test for Cosmic Hemispherical Asymmetry in the Cosmic Microwave Background B-Mode Polarization.

    Science.gov (United States)

    Mukherjee, Suvodip; Souradeep, Tarun

    2016-06-01

    Recent measurements of the temperature field of the cosmic microwave background (CMB) provide tantalizing evidence for violation of statistical isotropy (SI) that constitutes a fundamental tenet of contemporary cosmology. CMB space based missions, WMAP, and Planck have observed a 7% departure in the SI temperature field at large angular scales. However, due to higher cosmic variance at low multipoles, the significance of this measurement is not expected to improve from any future CMB temperature measurements. We demonstrate that weak lensing of the CMB due to scalar perturbations produces a corresponding SI violation in B modes of CMB polarization at smaller angular scales. The measurability of this phenomenon depends upon the scales (l range) over which power asymmetry is present. Power asymmetry, which is restricted only to l<64 in the temperature field, cannot lead to any significant observable effect from this new window. However, this effect can put an independent bound on the spatial range of scales of hemispherical asymmetry present in the scalar sector.

  14. Superparamagnetic nanoparticle detection system by using a fundamental mode orthogonal fluxgate (FM-OFG gradiometer

    Directory of Open Access Journals (Sweden)

    Hikaru Karo

    2017-05-01

    Full Text Available A new magnetic nanoparticle detection system by using a fundamental mode orthogonal fluxgate (FM-OFG gradiometer and ac magnetizing coil has been developed. The FM-OFG gradiometer has an active canceling coil on each of its sensor heads against the common magnetic field input to avoid the saturation of the amorphous wire core by a strong ac magnetic field. In addition, the ac magnetizing coil has an adjusting capability to make ac magnetic field strength affecting each of the gradiometer heads equal, which allows us to use a high gain amplifier at the latter stage. Two types of the gradiometer are tested: one is parallel configuration in which two sensor heads are placed in parallel side by side, the other is axial configuration in which two sensor heads are placed axially. Detectable distance was investigated using a 5μL (≈100μg in Fe atomic amount magnetic nanoparticle sample. The maximum detectable distance for the parallel gradiometer is 17 mm, and that for the axial one is 18 mm.

  15. Spatially resolved observation of the fundamental and second harmonic standing kink modes using SDO/AIA

    Science.gov (United States)

    Pascoe, D. J.; Goddard, C. R.; Nakariakov, V. M.

    2016-09-01

    Aims: We consider a coronal loop kink oscillation observed by the Atmospheric Imaging Assembly (AIA) of the Solar Dynamics Observatory (SDO) which demonstrates two strong spectral components. The period of the lower frequency component being approximately twice that of the shorter frequency component suggests the presence of harmonics. Methods: We examine the presence of two longitudinal harmonics by investigating the spatial dependence of the loop oscillation. The time-dependent displacement of the loop is measured at 15 locations along the loop axis. For each position the displacement is fitted as the sum of two damped sinusoids, having periods P1 and P2, and a damping time τ. The shorter period component exhibits anti-phase oscillations in the loop legs. Results: We interpret the observation in terms of the first (global or fundamental) and second longitudinal harmonics of the standing kink mode. The strong excitation of the second harmonic appears connected to the preceding coronal mass ejection (CME) which displaced one of the loop legs. The oscillation parameters found are P1 = 5.00±0.62 min, P2 = 2.20±0.23 min, P1/ 2P2 = 1.15±0.22, and τ/P = 3.35 ± 1.45. A movie associated to Fig. 5 is available in electronic form at http://www.aanda.org

  16. Quasi-linearly polarized hybrid modes in tapered and metal-coated tips with circular apertures: understanding the functionality of aperture tips

    Science.gov (United States)

    Tugchin, B. N.; Janunts, N.; Steinert, M.; Dietrich, K.; Kley, E. B.; Tünnermann, A.; Pertsch, T.

    2017-06-01

    In this study, we investigate analytically and experimentally the roles of quasi-linearly polarized (LP), hybrid, plasmonic and photonic modes in optical detection and excitation with aperture tips in scanning near-field optical microscopy. Aperture tips are tapered and metal-coated optical fibers where small circular apertures are made at the apex. In aperture tips, there exist plasmonic modes that are bound at the interface of the metal cladding to the inner dielectric fiber and photonic modes that are guided in the area of the increased index in the dielectric fiber core. The fundamental photonic mode, although excited by the free-space Gaussian beam, experiences cutoff and turns into an evanescent mode. The photonic mode also becomes lossier than the plasmonic mode toward the tip aperture, and its power decay due to absorption and reflection is expected to be at least 10-9. In contrast, the fundamental plasmonic mode has no cutoff and thus reaches all the way to the tip aperture. Due to the non-adiabaticity of both modes’ propagations through the taper below a core radius of 600 nm, there occurs coupling between the modes. The transmission efficiency of the plasmonic mode, including the coupling efficiency and the propagation loss, is expected to be about 10-6 that is at least 3 orders of magnitude larger than that of the photonic mode. Toward the tip aperture, the longitudinal field of the photonic mode becomes stronger than the transverse ones while the transverse fields always dominate for the plasmonic mode. Experimentally, we obtain polarization resolved images of the near-field at the tip aperture and compare with the x- and y-components of the fundamental quasi-LP plasmonic and photonic modes. The results show that not only the pattern but also the intensity ratios of the x- and y-components of the aperture near-field match with that of the fundamental plasmonic mode. Consequently, we conclude that only the plasmonic mode reaches the tip aperture and

  17. The electron–phonon coupling of fundamental, overtone, and combination modes and its effects on the resonance Raman spectra

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shuo [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); College of Physics, Jilin University, Changchun 130012 (China); Li, Zhanlong; Wang, Shenghan; Gao, Shuqin [College of Physics, Jilin University, Changchun 130012 (China); Sun, Chenglin, E-mail: chenglin@jlu.edu.cn [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); College of Physics, Jilin University, Changchun 130012 (China); Li, Zuowei [College of Physics, Jilin University, Changchun 130012 (China)

    2015-12-15

    Highlights: • The Huang–Rhys factors and electron–phonon coupling constants are calculated. • The changes of overtone mode are larger than those of fundamental mode. • The variation pattern of electron–phonon coupling well interprets the changes of spectra. - Abstract: External field plays a very important role in the interaction between the π-electron transition and atomic vibration of polyenes. It has significant effects on both the Huang–Rhys factor and the electron–phonon coupling. In this paper, the visible absorption and resonance Raman spectra of all-trans-β-carotene are measured in the 345–295 K temperature range and it is found that the changes of the 0–1 and 0–2 vibration bands of the absorption spectra with the temperature lead to the different electron–phonon coupling of fundamental, overtone, and combination modes. The electron-phonon coupling constants of all the modes are calculated and analyzed under different temperatures. The variation law of the electron–phonon coupling with the temperature well interprets the changes of the resonance Raman spectra, such as the shift, intensity and line width of the overtone and combination modes, which are all greater than those of the fundamental modes.

  18. High-Order Interference Effect Introduced by Polarization Mode Coupling in Polarization--Maintaining Fiber and Its Identification.

    Science.gov (United States)

    Li, Chuang; Yang, Jun; Yu, Zhangjun; Yuan, Yonggui; Zhang, Jianzhong; Wu, Bing; Peng, Feng; Yuan, Libo

    2016-01-01

    The high-order interference (HOI)-The interferogram introduced by polarization mode couplings (PMC) of multiple perturbations-Will cause misjudgment of the realistic coupling points in polarization-maintaining fiber (PMF) which is tested with a white light interferometer (WLI) with large dynamic range. We present an optical path tracking (OPT) method for simplifying the analysis of HOI, and demonstrate the enhancement and suppression conditions for the HOIs. A strategy is proposed to readily identify HOI by altering the spliced angle between polarizers' pigtails and the PMF under test. Moreover, a PMF experiment with two perturbation points, for simplicity, is given as an example. As a result, all the characteristic interferograms including HOIs can be distinguished through just four measurements. Utilizing this identification method, we can estimate the realistic coupling points in PMFs and distinguish them from the interference signals including numerous HOIs.

  19. Modeling and analysis of polarization effects in Fourier domain mode-locked lasers.

    Science.gov (United States)

    Jirauschek, Christian; Huber, Robert

    2015-05-15

    We develop a theoretical model for Fourier domain mode-locked (FDML) lasers in a non-polarization-maintaining configuration, which is the most widely used type of FDML source. This theoretical approach is applied to analyze a widely wavelength-swept FDML setup, as used for picosecond pulse generation by temporal compression of the sweeps. We demonstrate that good agreement between simulation and experiment can only be obtained by including polarization effects due to fiber bending birefringence, polarization mode dispersion, and cross-phase modulation into the theoretical model. Notably, the polarization dynamics are shown to have a beneficial effect on the instantaneous linewidth, resulting in improved coherence and thus compressibility of the wavelength-swept FDML output.

  20. Distributed optical fiber sensor for spatial location of polarization mode coupling

    Science.gov (United States)

    Cokgor, Ilkan; Handerek, Vincent A.; Rogers, Alan J.

    1993-03-01

    Transverse stress applied to a highly birefringent fiber at an arbitrary angle (other than 0 or 90 degrees) to the fiber birefringence axes causes rotation of the birefringence axes and changes the beat length of the fiber in that section. If one of the polarization modes is excited at the input, coupling of light from one mode to the other will be observed at a stress point. The presentation describes a method for determining the locations of discrete mode coupling points spaced along a polarization maintaining fiber using a pump-prob architecture based on the optical Kerr effect. Probe light experiences coupling at different stress locations. Counterpropagating strong pump light also experiences coupling while inducing additional birefringence, and changing the polarization state of the probe at the output. This system may be made temperature independent by introducing a phase tracking/triggering system. The advantages and limitations of this technique are described.

  1. Polarization switch of four-wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Olausson, Christina Bjarnal Thulin;

    2015-01-01

    Degenerate spontaneous four-wave mixing is considered in a large mode area hybrid photonic crystal fiber. Numerical and experimental results show birefringence assisted four-wave mixing for a certain polarization state of the pump field. The parametric gain can be turned on and off by switching...... the polarization state of the pump field between the two principal axis of the hybrid photonic crystal fiber. (C) 2015 Optical Society of America...

  2. Polarization switch of four-wave mixing in large mode area hybrid photonic crystal fibers.

    Science.gov (United States)

    Petersen, Sidsel R; Alkeskjold, Thomas T; Olausson, Christina B; Lægsgaard, Jesper

    2015-02-15

    Degenerate spontaneous four-wave mixing is considered in a large mode area hybrid photonic crystal fiber. Numerical and experimental results show birefringence assisted four-wave mixing for a certain polarization state of the pump field. The parametric gain can be turned on and off by switching the polarization state of the pump field between the two principal axis of the hybrid photonic crystal fiber.

  3. ELECTROMAGNETIC FIELD MEASUREMENT OF FUNDAMENTAL AND HIGHER-ORDER MODES FOR 7-CELL CAVITY OF PETRA-II

    Energy Technology Data Exchange (ETDEWEB)

    Kawashima, Y.; Blednykh, A.; Cupolo, J.; Davidsaver, M.; Holub, B.; Ma, H.; Oliva, J.; Rose, J.; Sikora, R.; Yeddulla, M.

    2011-03-28

    The booster synchrotron for NSLS-II will include a 7-cell PETRA cavity, which was manufactured for the PETRA-II project at DESY. The cavity fundamental frequency operates at 500 MHz. In order to verify the impedances of the fundamental and higher-order modes (HOM), which were calculated by computer code, we measured the magnitude of the electromagnetic field of the fundamental acceleration mode and HOM using the bead-pull method. To keep the cavity body temperature constant, we used a chiller system to supply cooling water at 20 degrees C. The bead-pull measurement was automated with a computer. We encountered some issues during the measurement process due to the difficulty in measuring the electromagnetic field magnitude in a multi-cell cavity. We describe the method and apparatus for the field measurement, and the obtained results.

  4. Soliton mode locking fiber laser with an all-fiber polarization interference filter.

    Science.gov (United States)

    Yan, Zhijun; Wang, Hushan; Zhou, Kaiming; Wang, Yishan; Li, Cheng; Zhao, Wei; Zhang, Lin

    2012-11-01

    An erbium doped fiber ring laser achieving soliton mode locking by the use of an intra-cavity all-fiber polarization interference filter (AFPIF) has been demonstrated. To incorporate an AFPIF with relative narrow transmission bandwidth, the laser has produced clean soliton pulses of 1.2 ps duration at a repetition rate of 14.98 MHz with a polarization extinction ratio up to 25.7 dB. Moreover, we have demonstrated that the operating wavelength of the mode locking laser can be tuned over 20 nm range from 1545 to 1565 nm by thermally tuning the AFPIF cavity.

  5. Mode-evolution-based polarization rotation and coupling between silicon and hybrid plasmonic waveguides

    Science.gov (United States)

    Kim, Sangsik; Qi, Minghao

    2015-12-01

    Hybrid plasmonic (HP) modes allow strong optical field confinement and simultaneously low propagation loss, offering a potentially compact and efficient platform for on-chip photonic applications. However, their implementation is hampered by the low coupling efficiency between dielectric guided modes and HP modes, caused by mode mismatch and polarization difference. In this work, we present a mode-evolution-based polarization rotation and coupling structure that adiabatically rotates the TE mode in a silicon waveguide and couples it to the HP mode in a strip silicon-dielectric-metal waveguide. Simulation shows that high coupling factors of 92%, 78%, 75%, and 73% are achievable using Ag, Au, Al, and Cu as the metal cap, respectively, at a conversion length of about 5 μm. For an extremely broad wavelength range of 1300-1800 nm, the coupling factor is >64% with a Ag metal cap, and the total back-reflection power, including all the mode reflections and backscattering, is below -40 dB, due to the adiabatic mode transition. Our device does not require high-resolution lithography and is tolerant to fabrication variations and imperfections. These attributes together make our device suitable for optical transport systems spanning all telecommunication bands.

  6. Propagation of a Scattered Electromagnetic Wave with P-Polarization (TE) Mode in Atmospheric Plasma

    Institute of Scientific and Technical Information of China (English)

    JIANG Zhong-He; HU Xi-Wei; LIU Ming-Hai; LAN Chao-Hui; HE Yong; ZHANG Shu; PAN Yuan

    2006-01-01

    @@ The finite-difference-time-domain method is applied to simulate the two-dimensional propagation ofa p-polarization mode electromagnetic wave in atmospheric plasma and metal layer for strong electron-neutral collisions. It is indicated that for a giving electron density profile, the p-polarization attenuation is very different from the spolarization attenuation and it depends even strongly on the incident angle. The mechanism of p-polarization attenuation is analysed by the interference of wave and the relationship between the attenuation property and the main parameters is given.

  7. Polarization Effects on Thermal-Induced Mode Instabilities in High Power Fiber Lasers

    CERN Document Server

    Tao, Rumao; Wang, Xiaolin; Zhou, Pu; Liu, Zejin

    2015-01-01

    We present detailed studies of the effect of polarization on thermal-induced mode instability (MI) in ytterbium-doped fiber amplifiers. Based on a steady-state theoretical model, which takes both electric fields along the two principal axes into consideration, the effect of polarization effects on the gain of Stokes wave was analyzed, which shows that the polarization characteristics of the fiber laser have no impact on the threshold of MI. Experimental validation of the theoretical analysis is presented with experimental results agreeing well with the theoretical results, in which polarization-maintained and non-polarization-maintained fiber lasers with core/inner cladding diameter of 30/250um and core NA of 0.07 were employed. The MI threshold power is measured to be about 367~386W.

  8. Probing the statistical properties of CMB $B$-mode polarization through Minkowski Functionals

    CERN Document Server

    Zhao, W

    2015-01-01

    The detection of the magnetic type $B$-mode polarization is the main goal of future cosmic microwave background (CMB) experiments. In the standard model, the $B$-mode map is a strongly non-gaussian field due to the lensed component. Besides the two-point correlation function, the other statistics are also very important to dig the information of the polarization map. In this paper, we employ the Minkowski functionals to study the morphological properties of the lensed $B$-mode maps. We find that the deviations from Gaussianity are very significant for both full and partial-sky surveys. As an application of the analysis, we investigate the morphological imprints of the foreground residuals in the $B$-mode map. We find that even for very tiny foreground residuals, the effects on the map can be detected by the Minkowski functional analysis. Therefore, it provides a complementary way to investigate the foreground contaminations in the CMB studies.

  9. Probing the statistical properties of CMB B-mode polarization through Minkowski functionals

    Science.gov (United States)

    Santos, Larissa; Wang, Kai; Zhao, Wen

    2016-07-01

    The detection of the magnetic type B-mode polarization is the main goal of future cosmic microwave background (CMB) experiments. In the standard model, the B-mode map is a strong non-gaussian field due to the CMB lensing component. Besides the two-point correlation function, the other statistics are also very important to dig the information of the polarization map. In this paper, we employ the Minkowski functionals to study the morphological properties of the lensed B-mode maps. We find that the deviations from Gaussianity are very significant for both full and partial-sky surveys. As an application of the analysis, we investigate the morphological imprints of the foreground residuals in the B-mode map. We find that even for very tiny foreground residuals, the effects on the map can be detected by the Minkowski functional analysis. Therefore, it provides a complementary way to investigate the foreground contaminations in the CMB studies.

  10. Prediction of the Fundamental Mode Lamb Wave Reflection from a Crack-Like Discontinuity Using Eigen-Mode Expansion

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Seok [Doosan Heavy Industries and Construction, Changwon (Korea, Republic of); Jang, Chang Heui [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Lee, Jong Po [ANSCO Corp., Daejeon (Korea, Republic of)

    2010-06-15

    Based on the idea of eigen-mode expansion, a method to analyze the reflection of Lamb wave from a finite vertical discontinuity of plate is theoretically derived and verified by experiment. The theoretical prediction is in good agreement with the experimental result, and this strongly suggests that eigen-mode expansion method could be used for solution of inverse scattering problem for ultrasonic testing using Lamb wave

  11. Robust forecasts on fundamental physics from the foreground-obscured, gravitationally-lensed CMB polarization

    CERN Document Server

    Errard, Josquin; Peiris, Hiranya V; Jaffe, Andrew H

    2015-01-01

    [Abridged] Recent results from the BICEP, Keck Array and Planck collaborations demonstrate that Galactic foregrounds are an unavoidable obstacle in the search for evidence of inflationary gravitational waves in the cosmic microwave background (CMB) polarization. Beyond the foregrounds, the effect of lensing by intervening large-scale structure further obscures all but the strongest inflationary signals permitted by current data. With a plethora of ongoing and upcoming experiments aiming to measure these signatures, careful and self-consistent consideration of experiments' foreground- and lensing-removal capabilities is critical in obtaining credible forecasts of their performance. We investigate the capabilities of instruments such as Advanced ACTPol, BICEP3 and Keck Array, CLASS, EBEX10K, PIPER, Simons Array, SPT-3G and SPIDER, and projects as COrE+, LiteBIRD-ext, PIXIE and Stage IV, to clean contamination due to polarized synchrotron and dust from raw multi-frequency data, and remove lensing from the result...

  12. Microwave birefringent metamaterials for polarization conversion based on spoof surface plasmon polariton modes

    Science.gov (United States)

    Li, Yongfeng; Zhang, Jieqiu; Ma, Hua; Wang, Jiafu; Pang, Yongqiang; Feng, Dayi; Xu, Zhuo; Qu, Shaobo

    2016-10-01

    We propose the design of wideband birefringent metamaterials based on spoof surface plasmon polaritons (SSPPs). Spatial k-dispersion design of SSPP modes in metamaterials is adopted to achieve high-efficiency transmission of electromagnetic waves through the metamaterial layer. By anisotropic design, the transmission phase accumulation in metamaterials can be independently modulated for x- and y-polarized components of incident waves. Since the dispersion curve of SSPPs is nonlinear, frequency-dependent phase differences can be obtained between the two orthogonal components of transmitted waves. As an example, we demonstrate a microwave birefringent metamaterials composed of fishbone structures. The full-polarization-state conversions on the zero-longitude line of Poincaré sphere can be fulfilled twice in 6–20 GHz for both linearly polarized (LP) and circularly polarized (CP) waves incidence. Besides, at a given frequency, the full-polarization-state conversion can be achieved by changing the polarization angle of the incident LP waves. Both the simulation and experiment results verify the high-efficiency polarization conversion functions of the birefringent metamaterial, including circular-to-circular, circular-to-linear(linear-to-circular), linear-to-linear polarization conversions.

  13. Microwave birefringent metamaterials for polarization conversion based on spoof surface plasmon polariton modes

    Science.gov (United States)

    Li, Yongfeng; Zhang, Jieqiu; Ma, Hua; Wang, Jiafu; Pang, Yongqiang; Feng, Dayi; Xu, Zhuo; Qu, Shaobo

    2016-01-01

    We propose the design of wideband birefringent metamaterials based on spoof surface plasmon polaritons (SSPPs). Spatial k-dispersion design of SSPP modes in metamaterials is adopted to achieve high-efficiency transmission of electromagnetic waves through the metamaterial layer. By anisotropic design, the transmission phase accumulation in metamaterials can be independently modulated for x- and y-polarized components of incident waves. Since the dispersion curve of SSPPs is nonlinear, frequency-dependent phase differences can be obtained between the two orthogonal components of transmitted waves. As an example, we demonstrate a microwave birefringent metamaterials composed of fishbone structures. The full-polarization-state conversions on the zero-longitude line of Poincaré sphere can be fulfilled twice in 6–20 GHz for both linearly polarized (LP) and circularly polarized (CP) waves incidence. Besides, at a given frequency, the full-polarization-state conversion can be achieved by changing the polarization angle of the incident LP waves. Both the simulation and experiment results verify the high-efficiency polarization conversion functions of the birefringent metamaterial, including circular-to-circular, circular-to-linear(linear-to-circular), linear-to-linear polarization conversions. PMID:27698443

  14. Separation of Lamb waves modes using polarization filter of 3D laser measured signals

    Science.gov (United States)

    Ambrozinski, Lukasz; Stepinski, Tadeusz; Uhl, Tadeusz

    2015-04-01

    Interpretation of Lamb waves signals can rise serious difficulties due to their multi-modal nature. Different modes propagating with different velocities can be misleading with damage reflected components. As a solution to this problem we propose a technique capable of modes separation based on a polarization filter. Both S0 and A0 Lamb modes exhibit elliptical polarization, however, their polarization parameters, i.e. the ratios of in-plane and out-of-plane displacements and phase-shifts between these components are different. Furthermore, these parameters can be considered constant in a narrow frequency band. Therefore, if the vertical and horizontal components of the wave motion are available, it is possible to apply signal processing technique referred to as oblique polarization filter. This operation is based on phase-shifts and amplifications of the in- and out-of-plane components, which results in orthogonal, linearly polarized A0 and S0 waves signals. In this paper the proposed technique will be illustrated using both numerical simulations and experimental data. The simulations of wave propagation were performed using local interaction simulation approach (LISA) assuming isotropic material. The experiments were performed using 3D laser scanning Doppler vibrometer that allowed to capture the in-plane and out-of-plane wave components.

  15. a Global Shear Velocity Model of the Upper Mantle from New Fundamental and Higher Rayleigh Mode Measurements

    Science.gov (United States)

    Debayle, E.; Ricard, Y. R.

    2011-12-01

    We present a global SV-wave tomographic model of the upper mantle, built from a new dataset of fundamental and higher mode Rayleigh waveforms. We use an extension of the automated waveform inversion approach of Debayle (1999) designed to improve the extraction of fundamental and higher mode information from a single surface wave seismogram. The improvement is shown to be significant in the transition zone structure which is constrained by the higher modes. The new approach is fully automated and can be run on a Beowulf computer to process massive surface wave dataset. It has been used to match successfully over 350 000 fundamental and higher mode Rayleigh waveforms, corresponding to about 20 millions of new measurements extracted from the seismograms. For each seismogram, we obtain a path average shear velocity and quality factor model, and a set of fundamental and higher mode dispersion and attenuation curves compatible with the recorded waveform. The set of dispersion curves provides a global database for future finite frequency inversion. Our new 3D SV-wave tomographic model takes into account the effect of azimuthal anisotropy and is constrained with a lateral resolution of several hundred kilometers and a vertical resolution of a few tens of kilometers. In the uppermost 200 km, our model shows a very strong correlation with surface tectonics. The slow velocity signature of mid-oceanic ridges extend down to ~100 km depth while the high velocity signature of cratons vanishes below 200 km depth. At depth greater than 400 km, the pattern of seismic velocities appear relatively homogeneous at large scale, except for high velocity slabs which produce broad high velocity regions within the transition zone. Although resolution is still good, the region between 200 and 400 km is associated with a complex pattern of seismic heterogeneities showing no simple correlation with the shallower or deeper structure.

  16. Elliptically polarized modes for the unidirectional excitation of surface plasmon polaritons

    NARCIS (Netherlands)

    Compaijen, Paul J.; Malyshev, Victor A.; Knoester, Jasper

    2016-01-01

    We propose a new method for the directional excitation of surface plasmon polaritons by a metal nanoparticle antenna, based on the elliptical polarization of the normal modes of the antenna when it is in close proximity to a metallic substrate. The proposed theoretical model allows for the full char

  17. What can be learned from the lensed cosmic microwave background B-mode polarization power spectrum?

    CERN Document Server

    Smith, S; Rocha, G; Smith, Sarah; Challinor, Anthony; Rocha, Graca

    2006-01-01

    The effect of weak gravitational lensing on the cosmic microwave background (CMB) temperature anisotropies and polarization will provide access to cosmological information that cannot be obtained from the primary anisotropies alone. We compare the information content of the lensed B-mode polarization power spectrum, properly accounting for the non-Gaussian correlations between the power on different scales, with that of the unlensed CMB fields and the lensing potential. The latter represent the products of an (idealised) optimal analysis that exploits the lens-induced non-Gaussianity to reconstruct the fields. Compressing the non-Gaussian lensed CMB into power spectra is wasteful and leaves a tight degeneracy between the equation of state of dark energy and neutrino mass that is much stronger than in the more optimal analysis. Despite this, a power spectrum analysis will be a useful first step in analysing future B-mode polarization data. For this reason, we also consider how to extract accurate parameter con...

  18. Evaluating SAR polarization modes at L-band for forest classification purposes in Eastern Amazon, Brazil

    Science.gov (United States)

    Liesenberg, Veraldo; Gloaguen, Richard

    2013-04-01

    Single, interferometric dual, and quad-polarization mode data were evaluated for the characterization and classification of seven land use classes in an area with shifting cultivation practices located in the Eastern Amazon (Brazil). The Advanced Land-Observing Satellite (ALOS) Phased Array L-band Synthetic Aperture Radar (PALSAR) data were acquired during a six month interval. A clear-sky Landsat-5/TM image acquired at the same period was used as additional ground reference and as ancillary input data in the classification scheme. We evaluated backscattering intensity, polarimetric features, interferometric coherence and texture parameters for classification purposes using support vector machines (SVM) and feature selection. Results showed that the forest classes were characterized by low temporal backscattering intensity variability, low coherence and high entropy. Quad polarization mode performed better than dual and single polarizations but overall accuracies remain low and were affected by precipitation events on the date and prior SAR date acquisition. Misclassifications were reduced by integrating Landsat data and an overall accuracy of 85% was attained. The integration of Landsat to both quad and dual polarization modes showed similarity at the 5% significance level. SVM was not affected by SAR dimensionality and feature selection technique reveals that co-polarized channels as well as SAR derived parameters such as Alpha-Entropy decomposition were important ranked features after Landsat' near-infrared and green bands. We show that in absence of Landsat data, polarimetric features extracted from quad-polarization L-band increase classification accuracies when compared to single and dual polarization alone. We argue that the joint analysis of SAR and their derived parameters with optical data performs even better and thus encourage the further development of joint techniques under the Reducing Emissions from Deforestation and Degradation (REDD) mechanism.

  19. 1.3kW monolithic linearly-polarized single-mode MOPA and strategies for mitigating mode instabilities

    CERN Document Server

    Tao, Rumao; Wang, Xiaolin; Zhou, Pu; Liu, Zejin

    2014-01-01

    We report on the high power amplification of 1064nm linearly-polarized laser in all-fiber polarization-maintained MOPA, which can operate at output power level of 1.3kW. The main amplifier was pumped with six 915nm laser diodes, and the slope efficiency is 65.3%. The beam quality (M2) was measured to be <1.2 at full power operation. The polarization extinction rate of the fiber amplifier was measured to be above 94% before mode instabilities (MI) sets in, which reduced to about 90% after the onset of MI. Power scaling capability of strategies for suppressing MI is analyzed based on a novel semi-analytical model, the theoretical results of which agree with the experimental results. It shows that mitigating MI by coiling the gain fiber is an effective and practical way in standard double-cladding large mode area fiber, and, by tight coiling of the gain fiber to the radius of 5.5cm, the MI threshold can be increased to 3 times higher than that without coiling or loose coiling. Experimental study has been carr...

  20. Hybrid mode-locked erbium-doped all-fiber soliton laser with a distributed polarizer.

    Science.gov (United States)

    Chernykh, D S; Krylov, A A; Levchenko, A E; Grebenyukov, V V; Arutunyan, N R; Pozharov, A S; Obraztsova, E D; Dianov, E M

    2014-10-10

    A soliton-type erbium-doped all-fiber ring laser hybrid mode-locked with a co-action of arc-discharge single-walled carbon nanotubes (SWCNTs) and nonlinear polarization evolution (NPE) is demonstrated. For the first time, to the best of our knowledge, boron nitride-doped SWCNTs were used as a saturable absorber for passive mode-locking initiation. Moreover, the NPE was introduced through the implementation of the short-segment polarizing fiber. Owing to the NPE action in the laser cavity, significant pulse length shortening as well as pulse stability improvement were observed as compared with a SWCNTs-only mode-locked laser. The shortest achieved pulse width of near transform-limited solitons was 222 fs at the output average power of 9.1 mW and 45.5 MHz repetition frequency, corresponding to the 0.17 nJ pulse energy.

  1. Polarization-controlled gap-mode surface-enhanced Raman scattering with a single nanoparticle

    Science.gov (United States)

    Dou, Xiujie; Yang, Aiping; Min, Changjun; Du, Luping; Zhang, Yuquan; Weng, Xiaoyu; Yuan, Xiaocong

    2017-06-01

    Metallic nanoparticle-film gaps are widely used as high-efficiency surface-enhanced Raman scattering (SERS) substrates owing to the plasmonic hybridization of the propagating surface plasmon polaritons on the films and the localized surface plasmons on the nanoparticles. Here, based on both theoretical and experimental studies, we reveal the enhancement mechanism of gap-mode SERS in a single nanoparticle-film gap by comparing the SERS intensity under different incident polarizations. The results demonstrate that the SERS signal can be significantly enhanced under illumination with radial polarization and can be significantly suppressed under azimuthal polarization (as compared with under traditional linear polarization). This is attributed to the distinct longitudinal electric field distributions of the excited surface plasmon polaritons. The results of our work will be of great interest for single-particle SERS research and quantitative molecular detection.

  2. Comparison of soliton robustness with respect to polarization-mode dispersion with first-order polarization-mode dispersion compensated linear systems.

    Science.gov (United States)

    Xie, C; Karlsson, M; Sunnerud, H; Andrekson, P A

    2001-05-15

    Soliton robustness to polarization-mode dispersion (PMD) is compared, both analytically and numerically, with that of linear pulses that use first-order PMD compensation. It is found that soliton robustness to PMD is comparable with first-order PMD compensation and in some cases is even better. The effects of soliton control methods on soliton robustness to PMD were also investigated, and it was found that soliton control methods can significantly improve the soliton's robustness to PMD, particularly for long-distance systems.

  3. Orbital angular momentum generation and mode transformation with high efficiency using forked polarization gratings.

    Science.gov (United States)

    Li, Yanming; Kim, Jihwan; Escuti, Michael J

    2012-12-01

    We present a novel optical element that efficiently generates orbital angular momentum (OAM) of light and transforms light between OAM modes based on a polarization grating with a fork-shaped singularity. This forked polarization grating (FPG) is composed of liquid crystalline materials, and can be made either static or switchable with high diffraction efficiency (i.e., 100% theoretically) into a single order. By spatially varying the Pancharatnam-Berry phase, FPGs shape the wavefront and thus control the OAM mode. We demonstrate theoretically and empirically that a charge l(g) FPG creates helical modes with OAM charge ±l(g) when a gaussian beam is input, and more generally, transforms the incident helical mode with OAM charge l(in) into output modes with OAM charge l(in)±l(g). We also show for the first time that this conversion into a single mode can be very efficient (i.e., ∼95% experimentally) at visible wavelengths, and the relative power between the two possible output modes is polarization-controllable from 0% to ∼100%. We developed a fabrication method that substantially improves FPG quality and efficiency over prior work. We also successfully fabricated switchable FPGs, which can be electrically switched between an OAM generating/transforming state and a transmissive state. Our experimental results showed >92% conversion efficiency for both configurations at 633 nm. These holographically fabricated elements are compact (i.e., thin glass plates), lightweight, and easily optimized for nearly any wavelength from ultraviolet to infrared, for a wide range of OAM charge, and for large or small clear apertures. They are ideal elements for enhanced control of OAM, e.g., in optical trapping and high-capacity information.

  4. Polarization-maintaining higher-order mode fiber module with anomalous dispersion at 1 μm

    DEFF Research Database (Denmark)

    Larsen, Stine Højer Møller; Pedersen, Martin Erland Vestergaard; Grüner-Nielsen, L.

    2012-01-01

    This Letter demonstrates a polarization-maintaining higher-order mode fiber module that has anomalous dispersion at 1 μm. The group velocity dispersion of the module is measured, showing a split of the two polarization axes. The excellent polarization-maintaining properties of the relevant fiber...... modes for the higher-order mode fiber are likewise demonstrated employing a new simple method for the measurement of the beat length of higher-order modes at a single wavelength. The higher-order fiber module is intended for group velocity dispersion compensation....

  5. Polarization-maintaining higher-order mode fiber module with anomalous dispersion at 1 μm.

    Science.gov (United States)

    Larsen, S H M; Pedersen, M E V; Grüner-Nielsen, L; Yan, M F; Monberg, E M; Wisk, P W; Rottwitt, K

    2012-10-15

    This Letter demonstrates a polarization-maintaining higher-order mode fiber module that has anomalous dispersion at 1 μm. The group velocity dispersion of the module is measured, showing a split of the two polarization axes. The excellent polarization-maintaining properties of the relevant fiber modes for the higher-order mode fiber are likewise demonstrated employing a new simple method for the measurement of the beat length of higher-order modes at a single wavelength. The higher-order fiber module is intended for group velocity dispersion compensation.

  6. An improved calibration method using third order polarization mode crosstalk for optical coherence domain polarimetry

    Science.gov (United States)

    Yang, Zhe; Yang, Jun; Zhang, Haoliang; Li, Hanyang; Peng, Feng; Yuan, Yonggui; Cheng, Yongqing; Yuan, Libo

    2017-04-01

    We propose an improved optical coherence domain polarimetry (OCDP) calibration scheme by using polarization mode crosstalk (PMC). The scheme can be used to calibrate the OCDP system's measurement result about intensity of PMC. The intensity of 1st order PMCs are measured by polarization extinction ratio (PER) meter as the scale to transfer the standard into OCDP system, and the higher order PMCs formed by 1st orders are used to expand the scale. Specifying alignment angle of joint points and analyzer, we successfully use 3rd order PMCs and expand the range of calibration over -100 dB.

  7. Emission and propagation of Saturn kilometric radiation: Magnetoionic modes, beaming pattern, and polarization state

    Science.gov (United States)

    Lamy, L.; Cecconi, B.; Zarka, P.; Canu, P.; Schippers, P.; Kurth, W. S.; Mutel, R. L.; Gurnett, D. A.; Menietti, D.; Louarn, P.

    2011-04-01

    The Cassini mission crossed the source region of the Saturn kilometric radiation (SKR) on 17 October 2008. On this occasion, the Radio and Plasma Wave Science (RPWS) experiment detected both local and distant radio sources, while plasma parameters were measured in situ by the magnetometer and the Cassini Plasma Spectrometer. A goniopolarimetric inversion was applied to RPWS three-antenna electric measurements to determine the wave vector k and the complete state of polarization of detected waves. We identify broadband extraordinary (X) mode as well as narrowband ordinary (O) mode SKR at low frequencies. Within the source region, SKR is emitted just above the X mode cutoff frequency in a hot plasma, with a typical electron-to-wave energy conversion efficiency of ˜1% (2% peak). The knowledge of the k vector is then used to derive the locus of SKR sources in the kronian magnetosphere, which shows X and O components emanating from the same regions. We also compute the associated beaming angle at the source θ‧ = (k, -B) either from (1) in situ measurements or a model of the magnetic field vector (for local to distant sources) or (2) polarization measurements (for local sources). Obtained results, similar for both modes, suggest quasi-perpendicular emission for local sources, whereas the beaming pattern of distant sources appears as a hollow cone with a frequency-dependent constant aperture angle: θ‧ = 75° ± 15° below 300 kHz, decreasing at higher frequencies to reach θ‧ (1000 kHz) = 50° ± 25°. Finally, we investigate quantitatively the SKR polarization state, observed to be strongly elliptical at the source, and quasi-purely circular for sources located beyond approximately two kronian radii. We show that conditions of weak mode coupling are achieved along the raypath, under which the magnetoionic theory satisfactorily describes the evolution of the observed polarization. These results are analyzed comparatively with the auroral kilometric radiation at

  8. Robust forecasts on fundamental physics from the foreground-obscured, gravitationally-lensed CMB polarization

    Science.gov (United States)

    Errard, Josquin; Feeney, Stephen M.; Peiris, Hiranya V.; Jaffe, Andrew H.

    2016-03-01

    Recent results from the BICEP, Keck Array and Planck Collaborations demonstrate that Galactic foregrounds are an unavoidable obstacle in the search for evidence of inflationary gravitational waves in the cosmic microwave background (CMB) polarization. Beyond the foregrounds, the effect of lensing by intervening large-scale structure further obscures all but the strongest inflationary signals permitted by current data. With a plethora of ongoing and upcoming experiments aiming to measure these signatures, careful and self-consistent consideration of experiments' foreground- and lensing-removal capabilities is critical in obtaining credible forecasts of their performance. We investigate the capabilities of instruments such as Advanced ACTPol, BICEP3 and Keck Array, CLASS, EBEX10K, PIPER, Simons Array, SPT-3G and SPIDER, and projects as COrE+, LiteBIRD-ext, PIXIE and Stage IV, to clean contamination due to polarized synchrotron and dust from raw multi-frequency data, and remove lensing from the resulting co-added CMB maps (either using iterative CMB-only techniques or through cross-correlation with external data). Incorporating these effects, we present forecasts for the constraining power of these experiments in terms of inflationary physics, the neutrino sector, and dark energy parameters. Made publicly available through an online interface, this tool enables the next generation of CMB experiments to foreground-proof their designs, optimize their frequency coverage to maximize scientific output, and determine where cross-experimental collaboration would be most beneficial. We find that analyzing data from ground, balloon and space instruments in complementary combinations can significantly improve component separation performance, delensing, and cosmological constraints over individual datasets. In particular, we find that a combination of post-2020 ground- and space-based experiments could achieve constraints such as σ(r)~1.3×10-4, σ(nt)~0.03, σ( ns )~1.8×10

  9. Polarization dependent behavior of CdS around the first and second LO-phonon modes

    Energy Technology Data Exchange (ETDEWEB)

    Frausto-Reyes, C., E-mail: cfraus@cio.mx [Centro de Investigaciones en Optica AC, Unidad Aguascalientes, Prolong., Constitucion 607, Fracc. Reserva Loma Bonita, CP 20200, Apartado Postal 507, Ags. (Mexico); Molina-Contreras, J.R., E-mail: rmolina@correo.ita.mx [Departamento de Ingenieria Electrica y Electronica, Instituto Tecnologico de Aguascalientes, Av. Lopez Mateos 1081 Oriente, Fracc. Bonna Gens, CP 20256, Aguascalientes, Ags. (Mexico); Lopez-Alvarez, Y.F. [Departamento de Ingenieria Electrica y Electronica, Instituto Tecnologico de Aguascalientes, Av. Lopez Mateos 1081 Oriente, Fracc. Bonna Gens, CP 20256, Aguascalientes, Ags. (Mexico); Medel-Ruiz, C.I.; Perez Ladron de Guevara, H. [Universidad de Guadalajara, Centro Universitario de los Lagos, Av. Enrique Diaz de Leon s/n, Fracc. Paseos de la Montana, CP 47460, Lagos de Moreno, Jal. (Mexico); Ortiz-Morales, M. [Centro de Investigaciones en Optica AC, Unidad Aguascalientes, Prolong., Constitucion 607, Fracc. Reserva Loma Bonita, CP 20200, Apartado Postal 507, Ags. (Mexico)

    2010-10-25

    The present work report studies on resonant Raman experimental line shape for CdS around the first and second LO-phonon modes. The application of our method to the study of LO-phonon modes of CdS suggests that the scattered intensity is dominated by the surface and dependent on polarization. Results showed that the Raman spectra for CdS, roughly fall into three groups: a broad line-wing with apparent maxima around 194 cm{sup -1} in the range of 140 and 240 cm{sup -1} which can be ascribed to overtone scattering from acoustic phonons; a band near the 1LO phonon mode which can be attributed to a combination of one-phonon scattering and peak acoustic phonon and finally, a band near the 2LO phonon mode which can be attributed to a combination of two-phonon scattering and peak acoustic phonon.

  10. Quasi-Linear Polarized Modes in Y-Rotated Piezoelectric GaPO4 Plates

    Directory of Open Access Journals (Sweden)

    Cinzia Caliendo

    2014-07-01

    Full Text Available The propagation of both surface and flexural acoustic plate modes along y-rotated x-propagation GaPO4 piezoelectric substrates was studied for several y-cut angles: the phase velocity and coupling coefficient dispersion curves were theoretically calculated for two different electroacoustic coupling configurations. The investigation of the acoustic field profile across the plate thickness revealed the presence of thin plate modes having polarization predominantly oriented along the propagation direction, and hence suitable for operation in liquid environment. These modes include the linearly polarized Anisimkin Jr. and the quasi longitudinal plate modes, AMs and QLs, showing a phase velocity close to that of the longitudinal bulk acoustic wave propagating in the same direction. The temperature coefficient of delay (TCD of these longitudinal modes was investigated in the −20 to 420 °C temperature range, in order to identify thermally stable or low TCD cuts. The power flow angle, i.e., the angle between the phase and group velocity vectors, was also estimated to evaluate the substrate anisotropy effect on the acoustic wave propagation. The GaPO4 intrinsic properties, such as its resistance to high temperature and its chemical inertness, make it especially attractive for the development of acoustic waves-based sensors for applications in harsh liquid environment.

  11. Bright source of spectrally pure polarization-entangled photons with nearly single-mode emission

    CERN Document Server

    Evans, P G; Bennink, R S; Grice, W P; Humble, T S

    2010-01-01

    We present results of a bright entangled photon source operating at 1552 nm via type-II collinear degenerate spontaneous parametric down-conversion in periodically poled KTP crystal. We report a conservative inferred pair generation rate of 44,000/s/mW into collection modes. Minimization of spectral and spatial entanglement was achieved by group velocity matching the pump, signal and idler modes and through properly focusing the pump beam. By utilizing a pair of calcite beam displacers, we are able to overlap photons from adjacent collinear sources to obtain polarization-entanglement visibility of 94.7 +/- 1.1% with accidentals subtracted.

  12. Cosmic birefringence fluctuations and cosmic microwave background B-mode polarization

    Directory of Open Access Journals (Sweden)

    Seokcheon Lee

    2015-06-01

    Full Text Available Recently, BICEP2 measurements of the cosmic microwave background (CMB B-mode polarization has indicated the presence of primordial gravitational waves at degree angular scales, inferring the tensor-to-scalar ratio of r=0.2 and a running scalar spectral index, provided that dust contamination is low. In this Letter, we show that the existence of the fluctuations of cosmological birefringence can give rise to CMB B-mode polarization that fits BICEP2 data with r<0.11 and no running of the scalar spectral index. When dust contribution is taken into account, we derive an upper limit on the cosmological birefringence, Aβ2<0.0075, where A is the amplitude of birefringence fluctuations that couple to electromagnetism with a coupling strength β.

  13. Flattop pulse generation based on the combined action of active mode locking and nonlinear polarization rotation.

    Science.gov (United States)

    Fang, Xiaohui; Wai, P K A; Lu, Chao; Chen, Jinhua

    2014-02-10

    A pulse-width-tunable 10 GHz flattop pulse (FTP) train is generated based on the combined action of active mode locking and nonlinear polarization rotation pulse shaping. Although the setup was previously used for other applications, the mechanism of FTP generation based on it is first analyzed and confirmed in the experiment. An FTP with pulse width tunable from 12 to 20 ps by changing polarization controllers is generated within the wavelength tuning range of 20 nm. The generated pulse reveals good stability, with the side mode suppression ratio of 65 dB, timing jitter of 92 fs, and amplitude fluctuation of 0.36%.

  14. A Mode-Sum Prescription for Vacuum Polarization in Odd Dimensions

    CERN Document Server

    Taylor, Peter

    2016-01-01

    We present a new mode-sum regularization prescription for computing the vacuum polarization of a scalar field in static spherically-symmetric black hole spacetimes in odd dimensions. This is the first general and systematic approach to regularized vacuum polarization in higher dimensions. Remarkably, the regularization parameters can be computed in closed form in arbitrary dimensions and for arbitrary metric function $f(r)$. In fact, we show that in spite of the increasing severity and number of the divergences to be regularized, the method presented is mostly agnostic to the number of dimensions. Finally, as an explicit example of our method, we show plots for vacuum polarization in Schwarzschild-Tangherlini spacetime for odd $d=5,...,11$.

  15. Birefringence and dispersion of cylindrically polarized modes in nanobore photonic crystal fiber

    CERN Document Server

    Euser, T G; Joly, N Y; Gabriel, C; Marquardt, C; Zang, L Y; Förtsch, M; Banzer, P; Brenn, A; Elser, D; Scharrer, M; Leuchs, G; Russell, P St J

    2010-01-01

    We demonstrate experimentally and theoretically that a nanoscale hollow channel placed centrally in the solid glass core of a photonic crystal fiber strongly enhances the cylindrical birefringence (the modal index difference between radially and azimuthally polarized modes). Furthermore, it causes a large split in group velocity and group velocity dispersion. We show analytically that all three parameters can be varied over a wide range by tuning the diameters of the nanobore and the core.

  16. Infra red active modes due to coupling of cyclotron excitation and LO phonons in polar semiconductor

    Science.gov (United States)

    Agrawal, Ratna; Dubey, Swati; Ghosh, S.

    2013-06-01

    Effects of free carrier concentration, external magnetic field and Callen effective charge on infra red active modes in a polar semiconductor have been analytically investigated using simple harmonic oscillator model. Callen effective charge considerably enhances reflectivity and shifts minima towards lower values of energy. Presence of magnetic field leads towards the coupling of collective cyclotron excitations with LO phonon giving rise to maximum reflectivity whereas cyclotron resonance absorption results into minimum reflectivity.

  17. Voice of the dragon: the mystery of the missing fundamental mode

    NARCIS (Netherlands)

    Tonon, D.; Nakiboglu, G.; Golliard, J.; Hirschberg, A.

    2010-01-01

    When a corrugated pipe is swirled it produces a musically interesting sound. By increasing its rotational speed one can produce a series of frequencies corresponding to the modes of the open-open pipe. An interesting issue, raised since the early studies on the whistling of corrugated pipes, is that

  18. Experimental Array for Generating Dual Circularly-Polarized Dual-Mode OAM Radio Beams

    Science.gov (United States)

    Bai, Xu-Dong; Liang, Xian-Ling; Sun, Yun-Tao; Hu, Peng-Cheng; Yao, Yu; Wang, Kun; Geng, Jun-Ping; Jin, Rong-Hong

    2017-01-01

    Recently, vortex beam carrying orbital angular momentum (OAM) for radio communications has attracted much attention for its potential of transmitting multiple signals simultaneously at the same frequency, which can be used to increase the channel capacity. However, most of the methods for getting multi-mode OAM radio beams are of complicated structure and very high cost. This paper provides an effective solution of generating dual circularly-polarized (CP) dual-mode OAM beams. The antenna consists of four dual-CP elements which are sequentially rotated 90 degrees in the clockwise direction. Different from all previous published research relating to OAM generation by phased arrays, the four elements are fed with the same phase for both left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP). The dual-mode operation for OAM is achieved through the opposite phase differences generated for LHCP and RHCP, when the dual-CP elements are sequentially rotated in the clockwise direction. The measured results coincide well with the simulated ones, which verified the effectiveness of the proposed design.

  19. Wavelet reconstruction of E and B modes for CMB polarization and cosmic shear analyses

    Science.gov (United States)

    Leistedt, Boris; McEwen, Jason D.; Büttner, Martin; Peiris, Hiranya V.

    2017-04-01

    We present new methods for mapping the curl-free (E-mode) and divergence-free (B-mode) components of spin 2 signals using spin directional wavelets. Our methods are equally applicable to measurements of the polarization of the cosmic microwave background (CMB) and the shear of galaxy shapes due to weak gravitational lensing. We derive pseudo- and pure wavelet estimators, where E-B mixing arising due to incomplete sky coverage is suppressed in wavelet space using scale- and orientation-dependent masking and weighting schemes. In the case of the pure estimator, ambiguous modes (which have vanishing curl and divergence simultaneously on the incomplete sky) are also cancelled. On simulations, we demonstrate the improvement (i.e. reduction in leakage) provided by our wavelet space estimators over standard harmonic space approaches. Our new methods can be directly interfaced in a coherent and computationally efficient manner with component separation or feature extraction techniques that also exploit wavelets.

  20. High-order polarization mode crosstalk effect: a calibration scheme of white light-based optical coherence domain polarimetry

    Science.gov (United States)

    Wu, Bing; Yang, Jun; Zhang, Jianzhong; Liang, Shuai; Yu, Zhangjun; Yuan, Yonggui; Peng, Feng; Zhou, Ai; Zhang, Yu; Yuan, Libo

    2015-09-01

    We propose a calibration scheme of the white light interferometer based optical coherence domain polarimetry (OCDP), which could be used to measure the ultra-weak polarization mode crosstalk (PMC) or the ultra-high polarization extinction ratio (PER) of different polarization optical devices. The calibration depends on the first and second order PMC effect of different polarization devices in series. The first and second PMCs between 0 and -90dB, established by five pieces of polarization maintaining fiber (PMF) and a Y-waveguide, is used to prove its feasibility.

  1. Tunable and switchable dual-wavelength Tm-doped mode-locked fiber laser by nonlinear polarization evolution.

    Science.gov (United States)

    Yan, Zhiyu; Li, Xiaohui; Tang, Yulong; Shum, Perry Ping; Yu, Xia; Zhang, Ying; Wang, Qi Jie

    2015-02-23

    We propose and demonstrate a tunable and switchable dual-wavelength ultra-fast Tm-doped fiber laser. The tunability is based on nonlinear polarization evolution (NPE) technique in a passively mode-locked laser cavity. The NPE effect induces wavelength-dependent loss in the cavity to effectively alleviate mode competition and enables the multiwavelength mode locking. The laser exhibits tunable dual-wavelength mode locking over a wide range from 1852 to 1886 nm. The system has compact structure and both the wavelength tuning and switching capabilities can be realized by controlling the polarization in the fiber ring cavity.

  2. Consideration of SH-wave fundamental modes in piezoelectromagnetic plate: electrically open and magnetically open boundary conditions

    Science.gov (United States)

    Zakharenko, A. A.

    2013-11-01

    This report studies the dispersive wave propagation in the transversely isotropic (6 mm) piezoelectromagnetic (PEM) plate when the mechanical, electrical, and magnetic boundary conditions for both the upper and lower free surfaces of the plate are as follows: the mechanically free, electrically open, and magnetically open surfaces. This study follows some original results obtained in book. The fundamental modes' dispersion relations are graphically shown for the following well-known PEM composite materials: BaTiO3-CoFe2O4 and PZT-5H-Terfenol-D. It is natural that for large values of the nondimensional parameter kd (k is the wave number and d is the plate half-thickness), the velocities of both the fundamental modes approach the surface shear-horizontal wave called the piezomagnetic exchange surface Melkumyan wave. It is well known that plate waves are usually utilized in the nondestructive testing and evaluation, for instance, in the airspace industry. Also, PEM materials are used as smart ones in various technical devices such as dispersive wave delay lines, (biochemi)sensors, lab-on-a-chip, etc.

  3. Molecular electronegativity in density functional theory(Ⅷ)——Charge polarization modes in a closed system

    Institute of Scientific and Technical Information of China (English)

    杨忠志; 王长生

    2000-01-01

    Based on the density functional theory and the atom-bond electronegativity equalization model (ABEEM), a method is proposed to construct the softness matrix and to obtain the electron population normal modes (PNMs) for a closed system. Using this method the information about the bond charge polarization in a molecule can be obtained easily. The test calculation shows that the PNM obtained by this method includes all the modes about the bond charge polarization explicitly. And the bond charge polarization mode characterized by the biggest eigenvalue, which is the softest one of all modes related with chemical bonds, can describe the charge polarization process in a molecule as exquisitely as the corresponding ab initio method.

  4. Sequential elution of multiply and singly phosphorylated peptides with polar-copolymerized mixed-mode RP18/SCX material.

    Science.gov (United States)

    Li, Xiuling; Guo, Zhimou; Sheng, Qianying; Xue, Xingya; Liang, Xinmiao

    2012-06-21

    Novel polar-copolymerized mixed-mode RP18/SCX material was developed for feasible phosphopeptide enrichment, in which multiply and singly phosphorylated peptides could be sequentially eluted and separated with high selectivity.

  5. Polarization-preserving holey fibers

    DEFF Research Database (Denmark)

    Broeng, Jes; Mogilevtsev, Dmitri; Libori, Stig E. Barkou

    2001-01-01

    In this work we suggest and discuss a microstructure of air capillaries with elliptical cross-section in a tread of glass that gives opportunity for Creation of polarization-preserving fiber with very small beat length between the fundamental modes of different polarization......In this work we suggest and discuss a microstructure of air capillaries with elliptical cross-section in a tread of glass that gives opportunity for Creation of polarization-preserving fiber with very small beat length between the fundamental modes of different polarization...

  6. Wavelength tunable stretched-pulse mode-locked all-fiber erbium ring laser with single polarization fiber.

    Science.gov (United States)

    Li, Shenping; Chen, Xin; Kuksenkov, Dmitri V; Koh, Joohyun; Li, Ming-Jun; Zenteno, Luis A; Nolan, Daniel A

    2006-06-26

    A wavelength tunable stretched-pulse mode-locked all-fiber ring laser using single polarization fiber (SPF) was demonstrated. In this laser, a segment of SPF was used simultaneously as a polarizer and a tunable filter in the laser cavity. Self-starting mode-locking with femtosecond output pulses was demonstrated. A wavelength tuning of ~20nm was achieved by bending the SPF with different radii.

  7. Isotropy-violation diagnostics for B-mode polarization foregrounds to the Cosmic Microwave Background

    Science.gov (United States)

    Rotti, Aditya; Huffenberger, Kevin

    2016-09-01

    Isotropy-violation statistics can highlight polarized galactic foregrounds that contaminate primordial B-modes in the Cosmic Microwave Background (CMB). We propose a particular isotropy-violation test and apply it to polarized Planck 353 GHz data, constructing a map that indicates B-mode foreground dust power over the sky. We build our main isotropy test in harmonic space via the bipolar spherical harmonic basis, and our method helps us to identify the least-contaminated directions. By this measure, there are regions of low foreground in and around the BICEP field, near the South Galactic Pole, and in the Northern Galactic Hemisphere. There is also a possible foreground feature in the BICEP field. We compare our results to those based on the local power spectrum, which is computed on discs using a version of the method of Planck Int. XXX (2016). The discs method is closely related to our isotropy-violation diagnostic. We pay special care to the treatment of noise, including chance correlations with the foregrounds. Currently we use our isotropy tool to assess the cleanest portions of the sky, but in the future such methods will allow isotropy-based null tests for foreground contamination in maps purported to measure primordial B-modes, particularly in cases of limited frequency coverage.

  8. Design of corrugated-horn-coupled MKID focal plane for CMB B-mode polarization

    Science.gov (United States)

    Sekimoto, Yutaro; Sekiguchi, Shigeyuki; Shu, Shibo; Sekine, Masakazu; Nitta, Tom; Naruse, Masato; Dominjon, Agnes; Hasebe, Takashi; Shan, Wenlei; Noguchi, Takashi; Miyachi, Akihira; Mita, Makoto; Kawasaki, Shigeo

    2016-07-01

    A focal plane based on MKID has been designed for cosmic microwave background (CMB) B-mode polarization experiments. We are designing and developing a focal plane with broadband corrugated horn array, planar OMT, 180 degree hybrid, bandpass filters, and MKIDs. The focal plane consists of 3 octave bands (55 - 108 GHz, 80 - 160 GHz, 160 - 320 GHz), 10 hexagonal modules. Broadband corrugated horn-array has been directly machined from an Al block and measured to have a good beam shape which is consistent with electromagnetic field simulations in octave bands. The horn array is designed to be low standing-wave, light weight, and electromagnetic shield. The broadband 4 probes ortho-mode transducer (OMT) is fabricated on Si membrane of an SOI wafer. A broadband 180 degree hybrid made with coplanar waveguide (CPW) is used to reduce higher modes of the circular waveguide. Two bandpass filters of each polarization are patterned with Nb microstrip. A prototype of the broadband corrugated horn coupled MKIDs has been fabricated and tested.

  9. Mapping of two-polarization-mode dynamics in vertical-cavity surface-emitting lasers with optical injection.

    Science.gov (United States)

    Gatare, I; Sciamanna, M; Nizette, M; Thienpont, H; Panajotov, K

    2009-08-01

    We report theoretically on the interplay between polarization switching and bifurcations to nonlinear dynamics in a vertical-cavity surface-emitting laser (VCSEL) subject to orthogonal optical injection. Qualitatively different bifurcation scenarios leading to polarization switching are found and mapped out in the plane of the injection parameters, i.e., the frequency detuning vs injection strength plane. A Hopf bifurcation mechanism on the two-polarization-mode solution determines the injection-locking boundaries and influences polarization switching induced by optical injection. We furthermore report on a torus bifurcation emerging from a two-linearly polarized (LP) mode time-periodic dynamics before polarization switching and injection locking appear. It corresponds to an interesting combination of relaxation oscillation dynamics in the x -LP mode together with wave mixing dynamics in the injected y -LP mode. In agreement with recent experiments, we unveil a period-doubling route to chaos that involves both VCSEL orthogonal LP modes. The corresponding region of chaotic dynamics coincides with abrupt changes in the polarization switching boundaries in the plane of the injection parameters.

  10. Testing statistics of the CMB B-mode polarization toward unambiguously establishing quantum fluctuation of vacuum

    CERN Document Server

    Shiraishi, Maresuke; Namba, Ryo; Namikawa, Toshiya; Hazumi, Masashi

    2016-01-01

    The B-mode polarization in the cosmic microwave background (CMB) anisotropies at large angular scales provides a smoking-gun evidence for the primordial gravitational waves (GWs). It is often stated that a discovery of the GWs establishes the quantum fluctuation of vacuum during the cosmic inflation. Since the GWs could also be generated by source fields, however, we need to check if a sizable signal exists due to such source fields before reaching a firm conclusion when the B-mode is discovered. Source fields of particular types can generate non-Gaussianity (NG) in the GWs. Testing statistics of the B-mode is a powerful way of detecting such NG. As a concrete example, we show a model in which a gauge field sources chiral GWs via a pseudoscalar coupling, and forecast the detection significance at the future CMB satellite LiteBIRD. Effects of residual foregrounds and lensing B-mode are both taken into account. We find the B-mode bispectrum "BBB" is in particular sensitive to the source-field NG, which is detec...

  11. Polarization Behavior Across Profile Modes For B0329+54: What Consistent Non-RVM Polarization Tells About the Emission Processes

    Science.gov (United States)

    Brinkman-Traverse, Casey; Rankin, Joanna M.; Mitra, Dipanjan

    2017-01-01

    In this paper, we analyze the quirky polarization behavior across different profile modes for the pulsar B0329+54. We have multi-frequency observations in both the normal and abnormal profile modes, and have identified a non-RVM polarization kink in the core component of the emission. Mitra et al initially identified this kink in the normal profile mode of the pulsar in 2007, and a mirror analysis has been done here for abnormal profile modes at three different frequencies. This kink is intensity dependent, showing up only in the abberated/retarded high intensity pulses, and is frequency independent. This parallel between profile modes shows that the same geometric phenomenon—a height dependent amplifier—is responsible for the non-RVM polarization behavior in each. The question then arises: what can be the source of the profile change, which does not change the polarization characteristics of the pulsar. This pulsar gives us a unique opportunity to study the process of pulsar emission by showing what cannot be responsible for switches in profile mode, and thus profile shape.

  12. Meta-Optical Chirality and Emergent Eigen-polarization Modes via Plasmon Interactions

    Science.gov (United States)

    Moocarme, Matthew; Proscia, Nicholas V.; Vuong, Luat T.

    2017-02-01

    The response of an individual meta-atom is often generalized to explain the collective response of a metasurface in a manner that neglects the interactions between meta-atoms. Here, we study a metasurface composed of tilted achiral meta-atoms with no spatial variation of the unit cell that derives appreciable optical chirality solely from the asymmetric interactions between meta-atoms. The interactions between meta-atoms are considered to stem from the Lorentz force arising from the Larmor radiation of adjacent plasmonic resonators because their inclusion in a simple model accurately predicts the bonding/anti- bonding modes that are measured experimentally. We also experimentally observe the emergence of multiple polarization eigenmodes, among other polarization-dependent responses, which cannot be modeled with the conventional formalism of transmission matrices. Our results are vital to the precise characterization and design of metasurfaces.

  13. Degree of circular polarization of soft X-rays emitted from a multi-polarization-mode undulator characterized by means of magnetic circular dichroism measurements.

    Science.gov (United States)

    Oura, Masaki; Nakamura, Tetsuya; Takeuchi, Tomoyuki; Senba, Yasunori; Ohashi, Haruhiko; Shirasawa, Katsutoshi; Tanaka, Takashi; Takeuchi, Masao; Furukawa, Yukito; Hirono, Toko; Ohata, Toru; Kitamura, Hideo; Shin, Shik

    2007-11-01

    The degree of circular polarization of soft X-rays emitted from the multi-polarization-mode undulator of BL17SU at SPring-8 has been deduced by means of magnetic circular dichroism in core-level X-ray absorption spectroscopy for a ferrimagnetic Gd-Fe-Co amorphous thin film. The results of reference measurements performed using well characterized undulator radiation of BL25SU at SPring-8 have also been utilized. The degrees of circular polarization were presumed for all the available operational modes and were compared with simple theoretical calculations. It was found that the calculated degrees of circular polarization were validated by the measurements reasonably well and will be useful in further experiments at BL17SU.

  14. An Analysis of Fundamental Waffle Mode in Early AEOS Adaptive Optics Images

    CERN Document Server

    Makidon, R B; Perrin, M D; Roberts, L C; Soummer, R; Oppenheimer, B R; Graham, J R

    2005-01-01

    Adaptive optics (AO) systems have significantly improved astronomical imaging capabilities over the last decade, and are revolutionizing the kinds of science possible with 4-5m class ground-based telescopes. A thorough understanding of AO system performance at the telescope can enable new frontiers of science as observations push AO systems to their performance limits. We look at recent advances with wave front reconstruction (WFR) on the Advanced Electro-Optical System (AEOS) 3.6 m telescope to show how progress made in improving WFR can be measured directly in improved science images. We describe how a "waffle mode" wave front error (which is not sensed by a Fried geometry Shack-Hartmann wave front sensor) affects the AO point-spread function (PSF). We model details of AEOS AO to simulate a PSF which matches the actual AO PSF in the I-band, and show that while the older observed AEOS PSF contained several times more waffle error than expected, improved WFR techniques noticeably improve AEOS AO performance. ...

  15. Generation of DQPSK format and its performance against polarization mode dispersion

    Institute of Scientific and Technical Information of China (English)

    Jing He; Lin Chen; Shuangchun Wen

    2009-01-01

    We propose a novel transmitter and receiver for differential quadrature phase-shift keying (DQPSK) format. The impact of the first-order polarization mode dispersion (PMD) on systems using DQPSK with 100-Gb/s non-return-to-zero (NRZ) or return-to-zero (RZ) format is investigated. Through computing the eye openings of DQPSK formats under different PMD conditions, it is found that NRZ DQPSK, as compared with RZ DQPSK, incurs smaller eye opening due to PMD. Carrier-suppressed return-to-zero (CSRZ) DQPSK format has better tolerance than RZ DQPSK format to PMD for a given bit rate.

  16. Polarization insensitive all-fiber mode-lockers functioned by carbon nanotubes deposited onto tapered fibers

    Science.gov (United States)

    Song, Yong-Won; Morimune, Keiyo; Set, Sze Y.; Yamashita, Shinji

    2007-01-01

    The authors demonstrate a nonblocked all-fiber mode locker operated by the interaction of carbon nanotubes with the evanescent field of propagating light in a tapered fiber. Symmetric cross section of the device with the randomly oriented nanotubes guarantees the polarization insensitive operation of the pulse formation. In order to minimize the scattering, the carbon nanotubes are deposited within a designed area around the tapered waist. The demonstrated passively pulsed laser has the repetition rate of 7.3MHz and the pulse width of 829fs.

  17. Polarization mode dispersion spectrum measurement via high-speed wavelength-parallel polarimetry.

    Science.gov (United States)

    Xu, Li; Wang, Shawn X; Miao, Houxun; Weiner, Andrew M

    2009-08-20

    We report experiments in which wavelength-parallel spectral polarimetry technology is used for measurement of the frequency-dependent polarization mode dispersion (PMD) vector. Experiments have been performed using either a grating spectral disperser, configured to provide 13.6 GHz spectral resolution over a 14 nm optical bandwidth, or a virtually imaged phased array spectral disperser, configured for 1.6 GHz spectral resolution over a 200 GHz band. Our results indicate that the spectral polarimetry data obtained via this approach are of sufficient quality to permit accurate extraction of the PMD spectrum. The wavelength-parallel spectral polarimetry approach allows data acquisition within a few milliseconds.

  18. A modified split—step fourier method for optical pulse propagation with polarization mode dispersion

    Institute of Scientific and Technical Information of China (English)

    RaoMin; SunXiao-Han; ZhangMing-De

    2003-01-01

    A modified split-step Fourier method (SSFM) is presented to solve the coupled nonlinear Schroedinger equation (CNLS) that can be used to model high-speed pulse propagation in optical fibres with polarization mode dispersion (PMD). We compare our approach with the SSFM and demonstrate that our approach is much faster with no loss of pre-chirped RZ(CRZ) formats in the presence of high PMD through this approach. The simulation results show that CRZ pulses are the most tolerant to high PMD values and the extinct ratio has a great impact on the transmission performance.

  19. Multichannel Adaptive Polarization Mode Dispersion Compensation with One Compensator in Dense Wavelength Division Multiplexing Transmission Systems

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qi; CHEN Ming-hua; ZHANG Ji-yu; XIE Shi-zhong

    2007-01-01

    A simple two-section polarization mode dispersion(PMD) compensator is proposed for multichannel PMD compensation, which can compensate two or even more channels simultaneously. Because of the statistical characteristics and the frequency-dependence of PMD, for current single mode fiber with moderate PMD, the probability that all channels are severely degraded at the same time is extremely small, which makes it possible to compensate a dense wavelength division multiplexing(DWDM) transmission system with moderate PMD using this compensator. It is shown that the outage probability of a 40×43Gb/s DWDM transmission system using this compensator is decreased significantly from 3.6×10-3 to 3.6×10-5.

  20. Time-delay signatures in multi-transverse mode VCSELs subject to double-cavity polarization-rotated optical feedback

    Science.gov (United States)

    Lin, Hong; Khurram, Aliza; Hong, Yanhua

    2016-10-01

    Time delay (TD) signatures are studied experimentally in orthogonal polarizations and in individual transverse modes respectively in a VCSEL operating with three transverse modes. Different types of concealment of the TD signatures are observed when the polarization of feedback is rotated through large angles. Effects of feedback strength and external cavity length on the TD signatures are investigated. Weak feedback leads to better concealment of the TD signatures in the dominant polarization. When the round-trip time difference between the two external cavities is close to a half of the relaxation oscillation period, the TD signatures are minimized.

  1. Passively mode-locked fiber laser based on polarization rotation in a multiple-quantum-well waveguide.

    Science.gov (United States)

    Okhotnikov, O G; Salcedo, J R

    1995-01-01

    We give experimental evidence for a new type of mode-locking mechanism for Er-doped fiber lasers based on polarization evolution in an intracavity multiple-quantum-well waveguide. Experiments indicate that anisotropic properties of waveguides can continuously start the mode-locking process.

  2. Dynamically coupled plasmon-phonon modes in GaP: An indirect-gap polar semiconductor

    Science.gov (United States)

    Ishioka, Kunie; Brixius, Kristina; Höfer, Ulrich; Rustagi, Avinash; Thatcher, Evan M.; Stanton, Christopher J.; Petek, Hrvoje

    2015-11-01

    The ultrafast coupling dynamics of coherent optical phonons and the photoexcited electron-hole plasma in the indirect gap semiconductor GaP are investigated by experiment and theory. For below-gap excitation and probing by 800-nm light, only the bare longitudinal optical (LO) phonons are observed. For above-gap excitation with 400-nm light, the photoexcitation creates a high density, nonequilibrium e -h plasma, which introduces an additional, faster decaying oscillation due to an LO phonon-plasmon coupled (LOPC) mode. The LOPC mode frequency exhibits very similar behavior for both n - and p -doped GaP, downshifting from the LO to the transverse optical (TO) phonon frequency limits with increasing photoexcited carrier density. We assign the LOPC mode to the LO phonons coupled with the photoexcited multicomponent plasma. For the 400-nm excitation, the majority of the photoexcited electrons are scattered from the Γ valley into the satellite X valley, while the light and spin-split holes are scattered into the heavy hole band, within 30 fs. The resulting mixed plasma is strongly damped, leading to the LOPC frequency appearing in the reststrahlen gap. Due to the large effective masses of the X electrons and heavy holes, the coupled mode appears most distinctly at carrier densities ≳5 ×1018cm-3 . We perform theoretical calculations of the nuclear motions and the electronic polarizations following an excitation with an ultrashort optical pulse to obtain the transient reflectivity responses of the coupled modes. We find that, while the longitudinal diffusion of photoexcited carriers is insignificant, the lateral inhomogeneity of the photoexcited carriers due to the laser intensity profile should be taken into account to reproduce the major features of the observed coupled mode dynamics.

  3. Testing statistics of the CMB B -mode polarization toward unambiguously establishing quantum fluctuation of the vacuum

    Science.gov (United States)

    Shiraishi, Maresuke; Hikage, Chiaki; Namba, Ryo; Namikawa, Toshiya; Hazumi, Masashi

    2016-08-01

    The B -mode polarization in the cosmic microwave background (CMB) anisotropies at large angular scales provides compelling evidence for the primordial gravitational waves (GWs). It is often stated that a discovery of the GWs establishes the quantum fluctuation of vacuum during the cosmic inflation. Since the GWs could also be generated by source fields, however, we need to check if a sizable signal exists due to such source fields before reaching a firm conclusion when the B mode is discovered. Source fields of particular types can generate non-Gaussianity (NG) in the GWs. Testing statistics of the B mode is a powerful way of detecting such NG. As a concrete example, we show a model in which gauge field sources chiral GWs via a pseudoscalar coupling and forecast the detection significance at the future CMB satellite LiteBIRD. Effects of residual foregrounds and lensing B mode are both taken into account. We find the B -mode bispectrum "BBB" is in particular sensitive to the source-field NG, which is detectable at LiteBIRD with a >3 σ significance. Therefore the search for the BBB will be indispensable toward unambiguously establishing quantum fluctuation of vacuum when the B mode is discovered. We also introduced the Minkowski functional to detect the NGs. While we find that the Minkowski functional is less efficient than the harmonic-space bispectrum estimator, it still serves as a useful cross-check. Finally, we also discuss the possibility of extracting clean information on parity violation of GWs and new types of parity-violating observables induced by lensing.

  4. Isotropy-Violation Diagnostics for $B$-mode Polarization Foregrounds to the Cosmic Microwave Background

    CERN Document Server

    Rotti, Aditya

    2016-01-01

    Isotropy-violation statistics can highlight polarized galactic foregrounds that contaminate primordial $B$-modes in the Cosmic Microwave Background (CMB). We propose a particular isotropy-violation test and apply it to polarized Planck 353 GHz data, constructing an map that indicates $B$-mode foreground dust power over the sky. We build our main isotropy test in harmonic space via the bipolar spherical harmonic basis, and our method helps us to identify the least-contaminated directions. By this measure, there are regions of low foreground in and around the BICEP field, near the South Galactic Pole, and in the Northern Galactic Hemisphere. There is also a possible foreground feature in the BICEP field. We compare our results to those based on the local power spectrum, which is computed on discs using a version of the method of Planck Int.~XXX (2016). The discs method is closely related to our isotropy-violation diagnostic. We pay special care to the treatment of noise, including chance correlations with the f...

  5. Robust polarization filter for separation of Lamb wave modes acquired using a 3D laser vibrometer

    Science.gov (United States)

    Ambroziński, Łukasz; Stepinski, Tadeusz

    2017-09-01

    Interpretation of signals related to Lamb waves propagation and scattering can rise serious difficulties due to the multi-modal nature of these waves. Different modes propagating with different velocities can be mixed up and hinder extraction of damage reflected components. As a feasible solution to this problem we propose a technique for separation of the propagating modes using a new type of polarization filter. The proposed directional polarization filter (DPF) can be applied if two components of particle movement, the in-plane and the out-of-plane, are available, for instance, from the measurement performed using laser vibrometer. The DPF is robust in the sense that it does not need a complete amplitude information of both components. Operation principle of the DPF is presented and illustrated by the simulated results in the form of B-scans obtained for an aluminum plate. The simulated results are verified by the experimental data obtained by processing the signals captured using a 3D laser vibrometer.

  6. High performance polarization-independent Quantum Dot Semiconductor Optical Amplifier with 22 dB fiber to fiber gain using Mode Propagation Tuning without additional polarization controller

    Science.gov (United States)

    Farmani, Ali; Farhang, Mahmoud; Sheikhi, Mohammad H.

    2017-08-01

    A detailed numerical investigation of polarization-independent quantum dot InAs/GaAs semiconductor optical amplifier (PIQS) based on a technique called mode propagation tuning (MPT) without the need for the polarization controller (PC) is reported, which can solve the limitation caused by polarization sensitivity in a semiconductor optical amplifier (SOA). Our calculations show that by a suitable tuning of the thickness of the active layer, only the TE0 and TM0 modes can propagate. Moreover, the gain saturation behavior of this SOA was measured at 1.55 μ m and found to be polarization-independent (PI). At active layer thickness of 1.7 μ m, the confinement factor was 0.75 and 0.7 for TE0 and TM0 modes, respectively, which leads to a gain difference up to 0.1 dB. The rate equations of the QD-SOA were also solved and a fiber to fiber gain of 22 dB was obtained. Additionally, a numerical simulation is presented which shows that the residual gain ripple and polarization sensitivity are sufficiently reduced when residual facet reflectivities of the SOA are in the range below 10-4 . In addition, the full-width at half-maximum of the horizontal and vertical far-field patterns (FFPs) are measured as 30° × 30°. The proposed structure can be used for logical applications.

  7. Displaced dual-mode imaging with desorption electrospray ionization for simultaneous mass spectrometry imaging in both polarities and with several scan modes

    DEFF Research Database (Denmark)

    Janfelt, Christian; Wellner, Niels; Hansen, Harald S

    2013-01-01

    Displaced dual-mode imaging (DDI) is introduced as a method for simultaneous imaging in positive and negative-ion mode on the same sample with desorption electrospray ionization imaging, as well as a method for simultaneous imaging in full-scan and tandem mass spectrometry (MS/MS) mode. DDI...... is performed by using a smaller row distance in the y-direction than the desired image resolution and recording for example every second row in positive-ion mode and the other half of the rows in negative-ion mode, thus resulting in two separate images. This causes some degree of oversampling, which is thus...... utilized to obtain complementary mass spectrometric of the sample. Imaging with both polarities is exemplified on an imprint of a Hypericum perforatum leaf containing secondary metabolites which ionize in both polarites and a mouse kidney containing phospholipids which ionize in positive or negative mode...

  8. Cross-splicing method for compensating fiber birefringence in polarization-maintaining fiber ring laser mode locked by nonlinear polarization evolution.

    Science.gov (United States)

    Wang, Yunzheng; Zhang, Liqiang; Zhuo, Zhuang; Guo, Songzhen

    2016-07-20

    We propose a cross-splicing method, for the first time to our knowledge, to compensate the effect of fiber birefringence in a polarization-maintaining fiber ring laser mode locked by nonlinear polarization evolution. This method has been investigated numerically and experimentally. The results indicate that stable mode-locking pulses can be obtained in the cavity with this method; otherwise, no mode-locking states are achieved. The design processes of the laser cavity are presented. Pulses with single pulse energy of 2.1 nJ are generated at pump power of 460 mW. The spectral bandwidth and pulse duration are 17.5 nm and 11.7 ps, respectively. The tunability of the laser is also studied. The central wavelength can be tuned from 1023.2 to 1045.9 nm.

  9. Single-mode and single-polarization photonics with anchored-membrane waveguides.

    Science.gov (United States)

    Chiles, Jeff; Fathpour, Sasan

    2016-08-22

    An integrated photonic platform with "anchored-membrane" structures, the T-Guide, is proposed, numerically investigated, fabricated and characterized. These compact air-clad structures have high index contrast and are much more stable than prior membrane-type structures. Their semi-infinite geometry enables single-mode and single-polarization (SMSP) operation over unprecedented bandwidths. Modal simulations quantify this behavior, showing that an SMSP window of 2.75 octaves (1.2-8.1 μm) is feasible for silicon T-Guides, spanning almost the entire transparency range of silicon. Dispersion engineering for T-Guides yields broad regions of anomalous group velocity dispersion, rendering them a promising platform for nonlinear applications such as wideband frequency conversion. Cut-back measurements of fabricated silicon T-guides at λ = 3.64 μm show low propagation losses of 1.75 ± 0.3 dB/cm.

  10. Optical vibration modes and electron-phonon interaction in ternary mixed crystals of polar semiconductors

    Institute of Scientific and Technical Information of China (English)

    Liang Xi-Xia; Ban Shi-Liang

    2004-01-01

    @@ Optical vibrations of the lattice and the electron-phonon interaction in polar ternary mixed crystals are studied in the framework of the continuum model of Born and Huang and the random-element-isodisplacement model. A normal-coordinate system to describe the optical vibration in ternary mixed crystals is correctly adopted to derive a new Frohlich-like Hamiltonian for the electron-phonon interaction including the unit-cell volume variation influence.The numerical results for the phonon modes, the electron-phonon coupling constants and the polaronic energies for several typical materials are obtained. It is verified that the nonlinearity of the electron-phonon coupling effects with the composition is essential and the unit-cell volume effects cannot be neglected for most ternary mixed crystals.

  11. A modified split-step Fourier method for optical pulse propagation with polarization mode dispersion

    Institute of Scientific and Technical Information of China (English)

    饶敏; 孙小菡; 张明德

    2003-01-01

    A modified split-step Fourier method (SSFM) is presented to solve the coupled nonlinear Schrǒdinger equation (CNLS) that can be used to model high-speed pulse propagation in optical fibres with polarization mode dispersion (PMD). We compare our approach with the SSFM and démonstrate that our approach is much faster with no loss of accuracy. We discuss the pulse distortion and system Q-factor of non-return-to-zero (NRZ), return-to-zero (RZ) and pre-chirped RZ (CRZ) formats in the presence of high PMD through this approach. The simulation results show that CRZ pulses are the most tolerant to high PMD wlues and the extinct ratio has a great impact on the transmission performance.

  12. Single-mode and single-polarization photonics with anchored-membrane waveguides

    CERN Document Server

    Chiles, Jeff

    2016-01-01

    An integrated photonic platform with anchored-membrane structures, the T-Guide, is proposed and numerically investigated. These compact air-clad structures have high index contrast and are much more stable than prior membrane-type structures. Their semi-infinite geometry enables single-mode and single-polarization (SMSP) operation over unprecedented bandwidths. Modal simulations quantify this behavior, showing that an SMSP window of 2.75 octaves (1.2 - 8.1 {\\mu}m) is feasible for silicon T-Guides, spanning almost the entire transparency range of silicon. Dispersion engineering for T-Guides yields broad regions of anomalous group velocity dispersion, rendering them a promising platform for nonlinear applications, such as wideband frequency conversion.

  13. Comparing calorimetric and dielectric polarization modes in viscous 2-ethyl-1-hexanol.

    Science.gov (United States)

    Huth, Heiko; Wang, Li-Min; Schick, Christoph; Richert, Ranko

    2007-03-14

    Dielectric relaxation and dynamic heat capacity measurements are compared for 2-ethyl-1-hexanol near its glass transition temperature Tg in order to further clarify the origin of the prominent Debye-type loss peak observed in many monohydroxy alcohols and other hydrogen-bonding liquids. While the dielectric spectrum epsilon" displays two distinct polarization processes that are separated by a factor of 2000 in terms of the peak frequency, the heat capacity cp" shows only a single peak. The dielectric process with lower amplitude and higher peak frequency coincides with the calorimetric signal, whereas the large dielectric Debye signal is not associated with calorimetric modes. The authors conclude that the Debye process corresponds to a transition among states which differ in energy only in the case of an external electric field.

  14. Polarization Maintaining, Very-Large-Mode Area, Er Fiber Amplifier for High Energy Pulses at 1572.3 nm

    Science.gov (United States)

    Nicholoson, J. W.; DeSantolo, A.; Yan, M. F.; Wisk, P.; Mangan, B.; Puc, G.; Yu, A.; Stephen, M.

    2016-01-01

    We demonstrate the first polarization maintaining, very-large-mode-area Er-doped fiber amplifier with 1000 square micron effective area. The amplifier is core pumped by a Raman fiber laser and is used to generate single frequency one microsecond pulses with pulse energy of 368 microJoules, M2 of 1.1, and polarization extinction greater than 20 dB. The amplifier operates at 1572.3 nm, a wavelength useful for trace atmospheric CO2 detection.

  15. Polarization switching from plasmonic lattice mode to multipolar localized surface plasmon resonances in arrays of large nanoantennas

    Science.gov (United States)

    Wing, Waylin J.; Sadeghi, Seyed M.; Gutha, Rithvik R.

    2016-12-01

    We experimentally investigate plasmonic lattice modes of gold nanoantenna arrays that occur in asymmetric structures containing a silica substrate and either air or a thin layer of a high-index dielectric. Very distinct polarization switching is observed in the nanoantenna arrays wherein by rotating the incident light polarization by ninety degrees, the array can exhibit either a plasmonic lattice mode or a multipolar localized surface plasmon resonance of varying nature. A large range of nanoantenna lengths are studied, and since the length of the nanoantennas dictates the multipolar localized surface plasmon resonance, we find that the characteristics of the polarization switching are affected accordingly. We also investigate how the thin layer of the high-index dielectric on top of the nanoantenna arrays, in conjunction with varying nanoantenna length, impacts the generation of plasmonic lattice modes and the polarization switching in the arrays. The high-index dielectric is found to assist in the generation and optical coupling of the plasmonic lattice modes. By altering the angle of incidence, the polarization switching can become very large, and the arrays can be made to selectively transmit light of certain wavelengths.

  16. Pulse width shaping of passively mode-locked soliton fiber laser via polarization control in carbon nanotube saturable absorber.

    Science.gov (United States)

    Jeong, Hwanseong; Choi, Sun Young; Rotermund, Fabian; Yeom, Dong-Il

    2013-11-04

    We report the continuous control of the pulse width of a passively mode-locked fiber laser via polarization state adjustment in a single-walled carbon nanotube saturable absorber (SWCNT-SA). The SWCNT, coated on the side-polished fiber, was fabricated with optimized conditions and used for stable mode-locking of the fiber laser without Q-switching instabilities for any polarization state of the laser intra-cavity. The 3-dB spectral bandwidth of the mode-locked pulses can be continuously tuned from 1.8 nm to 8.5 nm with the polarization control for a given laser cavity length and applied pump power. A pulse duration varying from 470 fs to 1.6 ps was also observed with a change in the spectral bandwidth. The linear and the nonlinear transmission properties of the SA were analyzed, and found to exhibit different modulation depths depending on the input polarization state in the SA. The largest modulation depth of the SA was observed at the polarization state of the transverse electric mode that delivers shortest pulses at the laser output.

  17. Dual-polarization and dual-mode orbital angular momentum radio vortex beam generated by using reflective metasurface

    Science.gov (United States)

    Yu, Shixing; Li, Long; Shi, Guangming

    2016-08-01

    A metasurface, which is composed of printed cross-dipole elements with different arm lengths, is designed, fabricated, and experimentally demonstrated to generate orbital angular momentum (OAM) vortex waves of dual polarizations and dual modes in the radio frequency domain simultaneously. The prototype of a practical metasurface is fabricated and measured to validate the results of theoretical analysis and design at 5.8 GHz. Numerical and experimental results verify that vortex waves with dual OAM modes and dual polarizations can be flexibly generated by using a reflective metasurface. The proposed method paves a way to generate diverse OAM vortex waves for radio frequency and microwave wireless communication applications.

  18. Constraints on Primordial Magnetic Fields from Planck combined with the South Pole Telescope CMB B-mode polarization measurements

    CERN Document Server

    Zucca, Alex; Pogosian, Levon

    2016-01-01

    A primordial magnetic field (PMF) present before recombination can leave specific signatures on the cosmic microwave background (CMB) fluctuations. Of particular importance is its contribution to the B-mode polarization power spectrum. Indeed, vortical modes sourced by the PMF can dominate the B-mode power spectrum on small scales, as they survive damping up to a small fraction of the Silk length. Therefore, measurements of the B-mode polarization at high-$\\ell$ , such as the one recently performed by the South Pole Telescope (SPT), have the potential to provide stringent constraints on the PMF. We use the publicly released SPT B-mode polarization spectrum, along with the temperature and polarization data from the Planck satellite, to derive constraints on the magnitude, the spectral index and the energy scale at which the PMF was generated. We find that, while Planck data constrains the magnetic amplitude to $B_{1 \\, \\text{Mpc}} < 3.3$ nG at 95\\% confidence level (CL), the SPT measurement improves the con...

  19. Design and analysis of a novel single-mode single-polarization photonic crystal fibre based on polarization-dependent coupling and absorption effect

    Institute of Scientific and Technical Information of China (English)

    Liu Xiao-Yi; Zhang Fang-Di; Zhang Min; Ye Pei-Da

    2007-01-01

    A novel single-mode single-polarization (SMSP) photonic crystal fibre has been proposed and analysed based on the polarization-dependent coupling and absorption effect via a full-vector finite element method with perfectly matched layers. The numerical results predict that very efficient SMSP operation can be achieved with both high bandwidth and high extinction ratio at low loss penalty. Effects of the fibre structural parameters on the SMSP bandwidth and extinction ratio have been explored, which will provide useful guide for the design and fabrication of the fibre. The results obtained will be instructive for the realization of new SMSP fibres with high performance.

  20. Period-Luminosity Relations Derived From the OGLE-III Fundamental Mode Cepheids II: The Small Magellanic Cloud Cepheids

    CERN Document Server

    Ngeow, Chow-Choong; Bhardwaj, Anupam; Singh, Harinder P

    2015-01-01

    In this paper we present multi-band period-luminosity (P-L) relations for fundamental mode Cepheids in the SMC. The optical VI-band mean magnitudes for these SMC Cepheids were taken from the third phase of the Optical Gravitational Lensing Experiment (OGLE-III) catalog. We also matched the OGLE-III SMC Cepheids to 2MASS and SAGE-SMC catalog to derive mean magnitudes in the JHK-bands and the four {\\it Spitzer} IRAC bands, respectively. All photometry was corrected for extinction by adopting the Zaritsky's extinction map. Cepheids with periods smaller than $\\sim2.5$ days were removed from the sample. In addition to the extinction corrected P-L relations in nine filters from optical to infrared, we also derived the extinction-free Wesenheit function for these Cepheids. We tested the nonlinearity of these SMC P-L relations (except the $8.0\\mu\\mathrm{m}$-band P-L relation) at 10 days: none of the P-L relations show statistically significant evidence of nonlinearity. When compared to the P-L relations in the LMC, t...

  1. Emission and propagation of Saturn kilometric radiation: magneto-ionic modes, beaming pattern and polarization state

    CERN Document Server

    Lamy, L; Zarka, P; Canu, P; Schippers, P; Kurth, W S; Mutel, R L; Gurnett, D A; Menietti, J D; Louarn, P

    2011-01-01

    The Cassini mission crossed the source region of the Saturn kilometric radiation (SKR) on 17 October 2008. On this occasion, the Radio and Plasma Wave Science (RPWS) experiment detected both local and distant radio sources, while plasma parameters were measured in situ by the magnetometer (MAG) and the Cassini Plasma Spectrometer (CAPS). A goniopolarimetric inversion was applied to RPWS 3-antenna electric measurements to determine the wave vector k and the complete state of polarization of detected waves. We identify broadband extraordinary (X) as well as narrowband ordinary (O) mode SKR at low frequencies. Within the source region, SKR is emitted just above the X mode cutoff frequency in a hot plasma, with a typical electron-to-wave energy conversion efficiency of 1% (2% peak). The knowledge of the k-vector is then used to derive the locus of SKR sources in the kronian magnetosphere, that shows X and O components emanating from the same regions. We also compute the associated beaming angle at the source thet...

  2. Fabrication of polarization-independent single-mode waveguides in lithium niobate crystal with femtosecond laser pulses

    CERN Document Server

    Qi, Jia; Liao, Yang; Chu, Wei; Liu, Zhengming; Wang, Zhaohui; Qiao, Lingling; Cheng, Ya

    2016-01-01

    We report on fabrication of depressed cladding optical waveguides buried in lithium niobate crystal with shaped femtosecond laser pulses. Depressed cladding waveguides of variable mode-field sizes are fabricated by forming the four sides of the cladding using a slit-beam shaping technique. We show that the waveguides fabricated by our technique allows single-mode propagation of the light polarized in both vertical and horizontal directions.

  3. MEASUREMENTS OF E-MODE POLARIZATION AND TEMPERATURE-E-MODE CORRELATION IN THE COSMIC MICROWAVE BACKGROUND FROM 100 SQUARE DEGREES OF SPTPOL DATA

    Energy Technology Data Exchange (ETDEWEB)

    Crites, A. T.; Henning, J. W.; Ade, P. A. R.; Aird, K. A.; Austermann, J. E.; Beall, J. A.; Bender, A. N.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Chiang, H. C.; Cho, H-M.; Citron, R.; Crawford, T. M.; Haan, T. de; Dobbs, M. A.; Everett, W.; Gallicchio, J.; Gao, J.; George, E. M.; Gilbert, A.; Halverson, N. W.; Hanson, D.; Harrington, N.; Hilton, G. C.; Holder, G. P.; Holzapfel, W. L.; Hoover, S.; Hou, Z.; Hrubes, J. D.; Huang, N.; Hubmayr, J.; Irwin, K. D.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Li, D.; Liang, C.; Luong-Van, D.; McMahon, J. J.; Mehl, J.; Meyer, S. S.; Mocanu, L.; Montroy, T. E.; Natoli, T.; Nibarger, J. P.; Novosad, V.; Padin, S.; Pryke, C.; Reichardt, C. L.; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Schaffer, K. K.; Smecher, G.; Stark, A. A.; Story, K. T.; Tucker, C.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Yefremenko, V.; Zahn, O.

    2015-05-18

    We present measurements of E-mode polarization and temperature-E-mode correlation in the cosmic microwave background using data from the first season of observations with SPTpol, the polarization-sensitive receiver currently installed on the South Pole Telescope (SPT). The observations used in this work cover 100 ${{{\\rm deg} }^{2}}$ of sky with arcminute resolution at 150 GHz. We report the E-mode angular auto-power spectrum (EE) and the temperature-E-mode angular cross-power spectrum (TE) over the multipole range 500 < ℓ ≤ 5000. These power spectra improve on previous measurements in the high-ℓ (small-scale) regime. We fit the combination of the SPTpol power spectra, data from Planck, and previous SPT measurements with a six-parameter ΛCDM cosmological model. We find that the best-fit parameters are consistent with previous results. The improvement in high-ℓ sensitivity over previous measurements leads to a significant improvement in the limit on polarized point-source power: after masking sources brighter than 50 mJy in unpolarized flux at 150 GHz, we find a 95% confidence upper limit on unclustered point-source power in the EE spectrum of ${{D}_{\\ell }}=\\ell (\\ell +1){{C}_{\\ell }}/2\\pi \\lt 0.40\\ \\mu {{{\\rm K}}^{2}}$ at $\\ell =3000$, indicating that future EE measurements will not be limited by power from unclustered point sources in the multipole range $\\ell \\lt 3600$, and possibly much higher in $\\ell .$

  4. Measurements of E-Mode Polarization and Temperature-E-Mode Correlation in the Cosmic Microwave Background from 100 Square Degrees of SPTpol Data

    Energy Technology Data Exchange (ETDEWEB)

    Crites, A.T.; et al.

    2015-05-18

    We present measurements of E-mode polarization and temperature-E-mode correlation in the cosmic microwave background using data from the first season of observations with SPTpol, the polarization-sensitive receiver currently installed on the South Pole Telescope (SPT). The observations used in this work cover 100 ${{{\\rm deg} }^{2}}$ of sky with arcminute resolution at 150 GHz. We report the E-mode angular auto-power spectrum (EE) and the temperature-E-mode angular cross-power spectrum (TE) over the multipole range 500 < ℓ ≤ 5000. These power spectra improve on previous measurements in the high-ℓ (small-scale) regime. We fit the combination of the SPTpol power spectra, data from Planck, and previous SPT measurements with a six-parameter ΛCDM cosmological model. We find that the best-fit parameters are consistent with previous results. The improvement in high-ℓ sensitivity over previous measurements leads to a significant improvement in the limit on polarized point-source power: after masking sources brighter than 50 mJy in unpolarized flux at 150 GHz, we find a 95% confidence upper limit on unclustered point-source power in the EE spectrum of ${{D}_{\\ell }}=\\ell (\\ell +1){{C}_{\\ell }}/2\\pi \\lt 0.40\\ \\mu {{{\\rm K}}^{2}}$ at $\\ell =3000$, indicating that future EE measurements will not be limited by power from unclustered point sources in the multipole range $\\ell \\lt 3600$, and possibly much higher in $\\ell .$

  5. A Measurement of the Cosmic Microwave Background B-Mode Polarization Power Spectrum at Sub-Degree Scales with POLARBEAR

    CERN Document Server

    Ade, P A R; Anthony, A E; Arnold, K; Atlas, M; Barron, D; Boettger, D; Borrill, J; Chapman, S; Chinone, Y; Dobbs, M; Elleflot, T; Errard, J; Fabbian, G; Feng, C; Flanigan, D; Gilbert, A; Grainger, W; Halverson, N W; Hasegawa, M; Hattori, K; Hazumi, M; Holzapfel, W L; Hori, Y; Howard, J; Hyland, P; Inoue, Y; Jaehnig, G C; Jaffe, A H; Keating, B; Kermish, Z; Keskitalo, R; Kisner, T; Jeune, M Le; Lee, A T; Leitch, E M; Linder, E; Lungu, M; Matsuda, F; Matsumura, T; Meng, X; Miller, N J; Morii, H; Moyerman, S; Myers, M J; Navaroli, M; Nishino, H; Paar, H; Peloton, J; Poletti, D; Quealy, E; Rebeiz, G; Reichardt, C L; Richards, P L; Ross, C; Schanning, I; Schenck, D E; Sherwin, B D; Shimizu, A; Shimmin, C; Shimon, M; Siritanasak, P; Smecher, G; Spieler, H; Stebor, N; Steinbach, B; Stompor, R; Suzuki, A; Takakura, S; Tomaru, T; Wilson, B; Yadav, A; Zahn, O

    2014-01-01

    We report a measurement of the B-mode polarization power spectrum in the cosmic microwave background (CMB) using the POLARBEAR experiment in Chile. The faint B-mode polarization signature carries information about the Universe's entire history of gravitational structure formation, and the cosmic inflation that may have occurred in the very early Universe. Our measurement covers the angular multipole range 500 < l < 2100 and is based on observations of 30 square degrees with 3.5 arcmin resolution at 150 GHz. On these angular scales, gravitational lensing of the CMB by intervening structure in the Universe is expected to be the dominant source of B-mode polarization. Including both systematic and statistical uncertainties, the hypothesis of no B-mode polarization power from gravitational lensing is rejected at 97.5% confidence. The band powers are consistent with the standard cosmological model. Fitting a single lensing amplitude parameter A_BB to the measured band powers, A_BB = 1.12 +/- 0.61 (stat) +0.0...

  6. Detection of B-mode Polarization in the Cosmic Microwave Background with Data from the South Pole Telescope

    CERN Document Server

    Hanson, D; Crites, A; Ade, P A R; Aird, K A; Austermann, J E; Beall, J A; Bender, A N; Benson, B A; Bleem, L E; Bock, J J; Carlstrom, J E; Chang, C L; Chiang, H C; Cho, H-M; Conley, A; Crawford, T M; de Haan, T; Dobbs, M A; Everett, W; Gallicchio, J; Gao, J; George, E M; Halverson, N W; Harrington, N; Henning, J W; Hilton, G C; Holder, G P; Holzapfel, W L; Hrubes, J D; Huang, N; Hubmayr, J; Irwin, K D; Keisler, R; Knox, L; Lee, A T; Leitch, E; Li, D; Liang, C; Luong-Van, D; Marsden, G; McMahon, J J; Mehl, J; Meyer, S S; Mocanu, L; Montroy, T E; Natoli, T; Nibarger, J P; Novosad, V; Padin, S; Pryke, C; Reichardt, C L; Ruhl, J E; Saliwanchik, B R; Sayre, J T; Schaffer, K K; Schulz, B; Smecher, G; Stark, A A; Story, K; Tucker, C; Vanderlinde, K; Vieira, J D; Viero, M P; Wang, G; Yefremenko, V; Zahn, O; Zemcov, M

    2013-01-01

    Gravitational lensing of the cosmic microwave background generates a curl pattern in the observed polarization. This "B-mode" signal provides a measure of the projected mass distribution over the entire observable Universe and also acts as a contaminant for the measurement of primordial gravity-wave signals. In this letter we present the first detection of gravitational lensing B modes, using first-season data from the polarization-sensitive receiver on the South Pole Telescope (SPTpol). We construct a template for the lensing B-mode signal by combining E-mode polarization measured by SPTpol with estimates of the lensing potential from a Herschel-SPIRE map of the cosmic infrared background. We compare this template to the B modes measured directly by SPTpol, finding a non-zero correlation at 7.7 sigma significance. The correlation has an amplitude and scale-dependence consistent with theoretical expectations, is robust with respect to analysis choices, and constitutes the first measurement of a powerful cosmo...

  7. A stable polarization switching laser from a bidirectional passively mode-locked thulium-doped fiber oscillator.

    Science.gov (United States)

    Zhou, Wei; Shen, Deyuan; Wang, Yishan; Ma, Hefeng; Wang, Fei

    2013-04-08

    We report on a novel polarization switching laser from a bidirectional passively mode-locked thulium(Tm)-doped fiber oscillator, which was characterized by the periodical change of polarization state of every pulse. The switching laser was created by combing two orthogonally stable vector solitons, which were found to be wave-breaking-free pulses in the all-anomalous-dispersion regime. The measured repetition rates of switching laser and the corresponding vector solitons were 49.596 MHz, 24.798 MHz, and 24.798MHz. By controlling wave plates, either of the polarized pulse trains can be switched on or off. To our knowledge, this is the first report of polarization switching laser with vector solitons in Tm fiber oscillators.

  8. Statistical characteristics and effects of polarization mode dispersion in dispersion managed soliton systems

    Institute of Scientific and Technical Information of China (English)

    XU Ming; JI Jian-hua

    2006-01-01

    Firstly,the JME(Jones matrix eigen) method is used to simulate the statistical characteristics of first- and second-order PMD in dispersion management system.Then,with help of the CNLSE (coupled nonlinear Schrdinger equations),the effects of PMD on DMS (dispersion managed soliton) transmission is studied with a variational method.The simplified relationships of the statistical parameters of second-order and first-order of PMD in dispersion management system have been gotten,from which the detailed information of second-order can be obtained,if the condition of DGD is given.The results have shown that the first and second-order PMD (polarization mode dispersion) vectors influence the evolution of energy and Mean square of time displacement of DMS in high-speed bit rates systems.When D1 stPMD>0.3 ps/km1/2,we must consider some means of control(for example the filter) to restrain the PMD.

  9. Ultra-High-Speed Travelling Wave Protection of Transmission Line Using Polarity Comparison Principle Based on Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Dong Wang

    2015-01-01

    Full Text Available The traditional polarity comparison based travelling wave protection, using the initial wave information, is affected by initial fault angle, bus structure, and external fault. And the relationship between the magnitude and polarity of travelling wave is ignored. Because of the protection tripping and malfunction, the further application of this protection principle is affected. Therefore, this paper presents an ultra-high-speed travelling wave protection using integral based polarity comparison principle. After empirical mode decomposition of the original travelling wave, the first-order intrinsic mode function is used as protection object. Based on the relationship between the magnitude and polarity of travelling wave, this paper demonstrates the feasibility of using travelling wave magnitude which contains polar information as direction criterion. And the paper integrates the direction criterion in a period after fault to avoid wave head detection failure. Through PSCAD simulation with the typical 500 kV transmission system, the reliability and sensitivity of travelling wave protection were verified under different factors’ affection.

  10. High-speed polarization-sensitive OCT at 1060 nm using a Fourier domain mode-locked swept source

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Torzicky, Teresa; Klein, Thomas;

    2012-01-01

    , polarization-maintaining or depolarizing areas within the sample. This information can be used to distinguish retinal layers and structures with different polarization properties. High imaging speed is crucial for imaging ocular structures in vivo in order to minimize motion artifacts while acquiring...... sufficiently large datasets. Here, we demonstrate PS-OCT imaging at 350 kHz A-scan rate using a two-channel PS-OCT system in conjunction with a Fourier domain mode-locked laser. The light source spectrum spans up to 100nm around the water absorption minimum at 1060 nm. By modulating the laser pump current, we...

  11. Impact of polarization mode dispersion and nonlinear effect on 40 Gbit/s dense wavelength division multiplexing system

    Institute of Scientific and Technical Information of China (English)

    SUN Xue-ming; ZHANG Hui-jian; ZUO Meng; GU Wan-yi; XU Da-xiong

    2006-01-01

    Dense wavelength division multiplexing (DWDM) system is the ultimate selection as an optical communication system because of its high speeds and capacities.However,the fiber nonlinear effects and polarization mode dispersion severely limit the performance of the system when signal propagates at 40 Gbit/s in a single channel.The coupled nonlinear Schr(o)dinger equations of a single channel in DWDM,which are all considered factors of group velocity dispersion (GVD),self phase modulation (SPM),cross phase modulation (XPM),four wave mixing (FWM) and polarization mode dispersion (PMD),are derived,while their number results are obtained with extended split-step Fourier method.Finally,to analyze the impacts of the fiber nonlinear effects and PMD on the optical communication system,the simulated results of an 8x40 Gbit/s DWDM system are discussed under different conditions respectively.

  12. Retrieval of Aerosol Fine-Mode Fraction from Intensity and Polarization Measurements by PARASOL over East Asia

    Directory of Open Access Journals (Sweden)

    Yang Zhang

    2016-05-01

    Full Text Available The fine-mode fraction (FMF of aerosol optical depth (AOD is a key optical parameter that represents the proportion of fine particles relative to total aerosols in the atmosphere. However, in comparison to ground-based measurements, the FMF is still difficult to retrieve from satellite observations, as attempted by a Moderate-resolution Imaging Spectroradiometer (MODIS algorithm. In this paper, we introduce the retrieval of FMF based on Polarization and Anisotropy of Reflectances for Atmospheric Science coupled with Observations from a Lidar (PARASOL data. This method takes advantage of the coincident multi-angle intensity and polarization measurements from a single satellite platform. In our method, we use intensity measurements to retrieve the total AOD and polarization measurements to retrieve the fine-mode AOD. The FMF is then calculated as the ratio of the retrieved fine-mode AOD to the total AOD. The important processes in our method include the estimation of the surface intensity and polarized reflectance by using two semi-empirical models, and the building of two sets of aerosol retrieval lookup tables for the intensity and polarized measurements via the 6SV radiative transfer code. We apply this method to East Asia, and comparisons of the retrieved FMFs for the Beijing, Xianghe and Seoul_SNU sites with those of the Aerosol Robotic Network (AERONET ground-based observations produce correlation coefficients (R2 of 0.838, 0.818, and 0.877, respectively. However, the comparison results are relatively poor (R2 = 0.537 in low-AOD areas, such as the Osaka site, due to the low signal-to-noise ratio of the satellite observations.

  13. Demonstration of ultra-broadband single-mode and single-polarization operation in T-Guides

    CERN Document Server

    Chiles, Jeff

    2016-01-01

    Silica-based anchored-membrane waveguides (T-Guides) are fabricated and characterized from the visible to infrared with streak imaging. It is numerically shown that the T-Guides can have wideband single-mode and single-polarization (SMSP) properties over a span of 2.6 octaves. Experimentally, a polarization-dependent loss difference of up to 90 dB/cm is measured between orthogonal polarizations, and a record SMSP window of >1.27 octaves is observed, limited only by the available measurement equipment. These measurements make a strong case for T-Guides for SMSP photonics, particularly on high-index materials such as our previous demonstration on silicon.

  14. Demonstration of ultra-broadband single-mode and single-polarization operation in T-Guides.

    Science.gov (United States)

    Chiles, Jeff; Fathpour, Sasan

    2016-08-15

    Silica-based anchored-membrane waveguides (T-Guides) are fabricated and characterized from the visible to infrared with streak imaging. It is numerically shown that the T-Guides can have wideband single-mode and single-polarization (SMSP) properties over a span of 2.6 octaves. Experimentally, a polarization-dependent loss difference of up to 89±19 dB/cm is measured between orthogonal polarizations and a record SMSP window of >1.27 octaves is observed, limited only by the available measurement equipment. These measurements make a strong case for T-Guides for SMSP photonics, particularly in high-index materials such as those in our previous demonstration on silicon.

  15. Two modes of interfacial pattern formation by atmospheric pressure helium plasma jet-ITO interactions under positive and negative polarity

    Science.gov (United States)

    Liu, Zhijie; Liu, Dingxin; Xu, Dehui; Cai, Haifeng; Xia, Wenjie; Wang, Bingchuan; Li, Qiaosong; Kong, Michael G.

    2017-05-01

    In this paper, we report the observation of an interfacial pattern formation on the ITO surface by atmospheric pressure helium plasma jet-ITO interactions. By changing the voltage polarity of positive and negative pulses, the interfacial phenomenon displays two different pattern modes, i.e. a double ring pattern with a combination of homogeneous and filamentous modes as well as a single ring pattern with a homogeneous mode. The reasons may mainly be attributed to the spread of a radially outward traveling surface ionization wave that would cause electric field distributions and charge accumulations on the ITO surface. The spatial-temporal distribution of \\text{N}2+≤ft({{B}2}{\\sum}\\text{u}+\\right) , He(3s3S), and O(3p5P) emissions are diagnosed to better understand the formation mechanism and the differences of plasma jet patterns under positive and negative polarities. Results show that the distribution of \\text{N}2+≤ft({{B}2}{\\sum}\\text{u}+\\right) emission is the main contributor for generating the filament structure in a double ring pattern for positive polarity, the homogeneous mode pattern mainly depends on the distribution of O(3p5P) emission for positive and negative polarity. Additionally, in order to further systematically understand the behaviors of plasma jet patterns, some parametric results, such as behaviors versus pulse peak voltage, dielectric material, pulse repetition rate, and flow rate are investigated. Some interesting phenomena and additional insights for the plasma jet pattern are found with different parametric conditions. This study might help to better understand effects of plasma jets in interaction with surfaces, or its application in the medical sector.

  16. The properties of photonic band gap and surface plasmon modes in the three-dimensional magnetized photonic crystals as the mixed polarized modes considered

    Science.gov (United States)

    Zhang, Hai-Feng; Liu, Shao-Bin; Jiang, Yu-Chi

    2015-04-01

    In this paper, the properties of photonic band gap (PBG) and surface plasmon modes in the three-dimensional (3D) magnetized plasma photonic crystals (MPPCs) with face-centered-cubic (fcc) lattices are theoretically investigated based on the plane wave expansion (PWE) method, in which the homogeneous magnetized plasma spheres are immersed in the homogeneous dielectric background, as the Voigt effects of magnetized plasma are considered (the incidence electromagnetic wave vector is perpendicular to the external magnetic field at any time). The dispersive properties of all of the EM modes are studied because the PBG is not only for the extraordinary and ordinary modes but also for the mixed polarized modes. The equations for PBGs also are theoretically deduced. The numerical results show that the PBG and a flatbands region can be observed. The effects of the dielectric constant of dielectric background, filling factor, plasma frequency and plasma cyclotron frequency (the external magnetic field) on the dispersive properties of all of the EM modes in such 3D MPPCs are investigated in detail, respectively. Theoretical simulations show that the PBG can be manipulated by the parameters as mentioned above. Compared to the conventional dielectric-air PCs with similar structure, the larger PBG can be obtained in such 3D MPPCs. It is also shown that the upper edge of flatbands region cannot be tuned by the filling factor and dielectric constant of dielectric background, but it can be manipulated by the plasma frequency and plasma cyclotron frequency.

  17. Three-party Quantum Secure Direct Communication with Single Photons in both Polarization and Spatial-mode Degrees of Freedom

    Science.gov (United States)

    Wang, LiLi; Ma, WenPing; Wang, MeiLing; Shen, DongSu

    2016-05-01

    We present an efficient three-party quantum secure direct communication (QSDC) protocol with single photos in both polarization and spatial-mode degrees of freedom. The three legal parties' messages can be encoded on the polarization and the spatial-mode states of single photons independently with desired unitary operations. A party can obtain the other two parties' messages simultaneously through a quantum channel. Because no extra public information is transmitted in the classical channels, the drawback of information leakage or classical correlation does not exist in the proposed scheme. Moreover, the comprehensive security analysis shows that the presented QSDC network protocol can defend the outsider eavesdropper's several sorts of attacks. Compared with the single photons with only one degree of freedom, our protocol based on the single photons in two degrees of freedom has higher capacity. Since the preparation and the measurement of single photon quantum states in both the polarization and the spatial-mode degrees of freedom are available with current quantum techniques, the proposed protocol is practical.

  18. Planck intermediate results XXXVIII. E- and B-modes of dust polarization from the magnetized filamentary structure of the interstellar medium

    DEFF Research Database (Denmark)

    Ade, P. A. R.; Aghanim, N.; Arnaud, M.

    2016-01-01

    , derived from their polarization angles. We present mean maps of the filaments in Stokes I, Q, U, E, and B, computed by stacking individual images rotated to align the orientations of the filaments. Combining the stacked images and the histogram of relative orientations, we estimate the mean polarization...... at high Galactic latitude, relevant to the study of dust emission as a polarized foreground to the CMB. We filter the intensity and polarization maps to isolate filaments in the range of angular scales where the power asymmetry between E-modes and B-modes is observed. Using the Smoothed Hessian Major Axis...

  19. Mueller matrix analysis for all optical fiber co-existence of birefringence-polarization dependent gain-mode coupling at a single wavelength

    Institute of Scientific and Technical Information of China (English)

    Shang Chio; Wu Chong-Qing; Li Zheng-Yong; Yang Shuang-Shou; Gao Kai-Qiang; Yu Kuang-Lu; Feng Zhen

    2011-01-01

    Birefringence (polarization-related phase-shift),polarization dependent gain (PDG) and mode coupling are three factors that may synchronously influence the transmission of single-wavelength polarized light in optical fibers.This paper obtains a new Mueller matrix analysis,which can be used under conditions that all these three factors are existing and changing.According to our transmission model,the state of polarization (SOP) changes along an optical microstructure fiber with co-existence of birefringence-PDG-mode coupling were simulated. The simulated results,which show the phenomena of SOP constringency,are in good agreement with previous theoretical analyses.

  20. Quasi interference of perpendicularly polarized guided modes observed with a photon scanning tunneling microscope

    NARCIS (Netherlands)

    Balistreri, M.L.M.; Driessen, A.; Korterik, Jeroen P.; Kuipers, L.; van Hulst, N.F.

    2000-01-01

    The simultaneous detection of TE- as well as TM-polarized light with a photon scanning tunneling microscope leads to a quasi- interference pattern of these mutually perpendicular polarized fields. This interference pattern has been observed in the optical field distribution as a function of both pos

  1. Vector solitons with locked and precessing states of polarization

    OpenAIRE

    Sergeyev, Sergey; Mou, Chengbo; Rozhin, Alex; Turitsyn, Sergei

    2012-01-01

    We demonstrate experimentally new families of vector solitons with locked and precessing states of polarization for fundamental and multipulse soliton operations in a carbon nanotube mode-locked fiber laser with anomalous dispersion laser cavity.

  2. Electro-optically generating and controlling right- and left-handed circularly polarized multiring modes of light beams.

    Science.gov (United States)

    Zhu, Wenguo; She, Weilong

    2012-07-15

    We propose a simple method for generating and controlling right- and left-handed circularly polarized (RHP and LHP) multiring modes of light beams by means of Pockels effect in a single strontium barium niobate (SBN) crystal. The numerical results show that an LHP Laguerre-Gaussian LG(0l) beam, propagating along the optical axis of the crystal, will partly turn into an RHP vortex light field of order l+2. Moreover, a pair of the LHP and RHP components of the output light field is LG-like modes sharing an identically radial index, which is electro-optically controllable. The power ratio between these two components depends on the applied electric field and the mode of input beam.

  3. Performance of low-cost few-mode fiber Bragg grating sensor systems: polarization sensitivity and linearity of temperature and strain response

    DEFF Research Database (Denmark)

    Ganziy, Denis; Rose, Bjarke; Bang, Ole

    2016-01-01

    We evaluate whether 850 nm fiber Bragg grating (FBG) sensor systems can use low-cost 1550 nm telecom fibers; in other words, how detrimental the influence of higher-order modes is to the polarization stability and linearity of the strain and temperature response. We do this by comparing...... polarization sensitivity of a few-mode 850 nm FBG sensor to a strictly single-mode 850 nm FBG sensor system using 850 nm single-mode fibers. We also compare the performance of the FBGs in strain and temperature tests. Our results show that the polarization stability and the linearity of the response degrade...... due to the presence of the higher-order modes. We demonstrate that, by using simple coiling of the 1550 nm fiber, one can regain the performance of the few-mode system and make it usable for high precision measurements....

  4. Model of multistep electron transfer in a single-mode polar medium

    Science.gov (United States)

    Feskov, S. V.; Yudanov, V. V.

    2017-09-01

    A mathematical model of multistep photoinduced electron transfer (PET) in a polar medium with a single relaxation time (Debye solvent) is developed. The model includes the polarization nonequilibrity formed in the vicinity of the donor-acceptor molecular system at the initial steps of photoreaction and its influence on the subsequent steps of PET. It is established that the results from numerical simulation of transient luminescence spectra of photoexcited donor-acceptor complexes (DAC) conform to calculated data obtained on the basis of the familiar experimental technique used to measure the relaxation function of solvent polarization in the vicinity of DAC in the picosecond and subpicosecond ranges.

  5. Analytical model and new structure of the enhancement-mode polarization-junction HEMT with vertical conduction channel

    Science.gov (United States)

    Yang, Chao; Xiong, Jiayun; Wei, Jie; Wu, Junfeng; Peng, Fu; Deng, Siyu; Zhang, Bo; Luo, Xiaorong

    2016-04-01

    A novel enhancement-mode (E-mode) polarization-junction HEMT with vertical conduction channel (PVC-HEMT) is proposed, and its analytical model for threshold voltage (Vth) is presented. It has two features: one is GaN/AlGaN/GaN double hetero-structure, the other is that source and drain locate at the same side of trench-type MOS gate (T-gate), and the source contacts with the T-gate, which forms vertical conduction channel (VC). The 2-D hole gas (2-DHG) and 2-D electron gas (2-DEG) are formed at the GaN-top/AlGaN and AlGaN/GaN-buffer interface, respectively, forming the polarization-junction. First, the E-mode operation is realized because 2-DHG under the source prevents the electrons injecting from source to 2-DEG, breaking through the conventional E-mode method by depleting 2-DEG under the gate. Second, a uniform electric field (E-field) distribution is achieved due to the assisted depletion effect by polarization-junction. Third, the source reduces the E-field peak at the T-gate side and modulates the E-field distribution. The breakdown voltage (BV) of PVC-HEMT is 705 V and specific ON-resistance (RON,sp) is 1.18 mΩ cm2. Compared with conventional HEMT (C-HEMT), PVC-HEMT has a smaller size due to the special location of the source and T-gate. An analytic threshold voltage model is presented and the analytical results agree well with the simulated results.

  6. Theoretical Calculation of System Performance of Fiber Optic Network with Chromatic Dispersion, Polarization Mode Dispersion, Polarization Dependent Loss, and Amplifier Spontaneous Emission Noise

    Science.gov (United States)

    Abuzariba, Suad Mohamed

    This thesis includes a theoretical study of the performance of an optical network system with linear impairments: chromatic dispersion (CD), polarization mode dispersion (PMD), polarization dependent loss (PDL), and amplified spontaneous emission (ASE) noise. Both the a-factor and bit error rate (BER) were used as performance parameters in this study. First, an analytical optical eye diagram evaluation for a system of highly mode coupled PMD/PDL fiber and lumped sections (up to fifteen sections) have been presented in this study. Based on this evaluation we found that with PDL considered as well as PMD, the a-factor of the output becomes higher than that of a Maxwellian fiber having the same total root mean-squared PMD and PDL values, when the mean-square PDL element of the lumped sections makes up the major portion of the total mean-square of the whole system. Whereas without considering PDL, the a-factor becomes higher as the mean-square PMD element of the Maxwellian fiber takes the major portion of the total mean-square PMD element of the whole system. Also the worst case for the a-factor occurred when the lumped sections were in the middle between two equivalent Maxwellian fibers, rether than if the lumped sections were followed by Maxwellian fiber or the Maxwellian fiber is followed by the lumped sections. We also note that two equivalent Maxwellian fibers connected in series will not give the same a-factor as a Maxwellian fiber equivalent calculated by concatenation rules unless they have the same values of PMD, PDL, and polarization direction correlation elements. Second, considering ASE-noise besides CD, PMD, and PDL, improved values of bit error rate (BER) were gotten using the moment generation function for the optical system in cases of ON-OFF modulation format and DPSK modulation format. We found that, even when considering the noise only without the signal, the probability density function of the output current was dependent on the output state of

  7. Planck intermediate results L. Evidence of spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB B-mode analysis

    DEFF Research Database (Denmark)

    Aghanim, N.; Ashdown, M.; Aumont, J.

    2017-01-01

    The characterization of the Galactic foregrounds has been shown to be the main obstacle in the challenging quest to detect primordial B-modes in the polarized microwave sky. We make use of the Planck-HFI 2015 data release at high frequencies to place new constraints on the properties of the polar...

  8. Measurement for polarization mode dispersion of LiNbO3 integrated waveguide modulator used white light interferometry

    Science.gov (United States)

    Yu, Zhangjun; Peng, Feng; Yang, Jun; Zhou, Ai; Liang, Shuai; Yuan, Yonggui; Wu, Bing; Zhang, Yu; Liu, Zhihai; Yuan, Libo

    2015-09-01

    We present a method to measure the polarization mode dispersion (PMD) of the LiNbO3 multifunctional integrated waveguide modulator (MFIWM) which is consist of a Y-waveguide, two extended polarization maintaining (PM) fibers, lead-in PM pigtail and lead-out PM pigtail. This method is based on an all-fiber time-domain scanning white light interferometer and utilizes fast Fourier transform (FFT) technology to obtain interferometric phase. The PMD of each part of MFIWM was measured and distinguished accurately. It's demonstrated that, the PMD of Y-waveguide is 13.5 ps/nm/km@1555nm which is approximately 40~160 times of the PMD of PM fibers in the MFIWM under test.

  9. High-Order Interference Effect Introduced by Polarization Mode Coupling in Polarization—Maintaining Fiber and Its Identification

    Directory of Open Access Journals (Sweden)

    Chuang Li

    2016-03-01

    Full Text Available The high-order interference (HOI—The interferogram introduced by polarization mode couplings (PMC of multiple perturbations—Will cause misjudgment of the realistic coupling points in polarization-maintaining fiber (PMF which is tested with a white light interferometer (WLI with large dynamic range. We present an optical path tracking (OPT method for simplifying the analysis of HOI, and demonstrate the enhancement and suppression conditions for the HOIs. A strategy is proposed to readily identify HOI by altering the spliced angle between polarizers’ pigtails and the PMF under test. Moreover, a PMF experiment with two perturbation points, for simplicity, is given as an example. As a result, all the characteristic interferograms including HOIs can be distinguished through just four measurements. Utilizing this identification method, we can estimate the realistic coupling points in PMFs and distinguish them from the interference signals including numerous HOIs.

  10. High-Order Interference Effect Introduced by Polarization Mode Coupling in Polarization—Maintaining Fiber and Its Identification

    Science.gov (United States)

    Li, Chuang; Yang, Jun; Yu, Zhangjun; Yuan, Yonggui; Zhang, Jianzhong; Wu, Bing; Peng, Feng; Yuan, Libo

    2016-01-01

    The high-order interference (HOI)—The interferogram introduced by polarization mode couplings (PMC) of multiple perturbations—Will cause misjudgment of the realistic coupling points in polarization-maintaining fiber (PMF) which is tested with a white light interferometer (WLI) with large dynamic range. We present an optical path tracking (OPT) method for simplifying the analysis of HOI, and demonstrate the enhancement and suppression conditions for the HOIs. A strategy is proposed to readily identify HOI by altering the spliced angle between polarizers’ pigtails and the PMF under test. Moreover, a PMF experiment with two perturbation points, for simplicity, is given as an example. As a result, all the characteristic interferograms including HOIs can be distinguished through just four measurements. Utilizing this identification method, we can estimate the realistic coupling points in PMFs and distinguish them from the interference signals including numerous HOIs. PMID:27011191

  11. Mathematical approximations for the amplitude of the fundamental mode field (LP01) of a dispersion shifted fiber at six wavelengths

    Science.gov (United States)

    Lamarche, Louis

    2009-06-01

    Hydro-Quebec optical network includes more than 5,000 km of optical ground wires [1] (OPGW) using dispersion shifted fibers (SMF-DSTM) [2]-[3]. This paper provides a model of the index profile for a typical reference fiber and the mathematical approximations of the amplitude of the LP01 mode at six important wavelengths (1.31, 1.41, 1.45, 1.48, 1.55, 1.625 μm). The fiber model has a triangular core and a quadratic ring shape. The weakly guided mode is obtained using the variational principle [4] implemented using an algorithm based on a Laguerre-Gauss-Bessel approximation of the field [5]. We modeled the wavelength dependence of the index of refraction of germanium doped silica using an experimental formula [6]. A comprehensive algorithm was developed to compute the normalized damping factor W and the normalized propagation constant U in the variational algorithm. The mode field diameter, group velocity and chromatic dispersion were also computed at the above wavelengths.

  12. Perturbations of gyrosynchrotron emission polarization from solar flares by sausage modes: forward modeling

    Science.gov (United States)

    Reznikova, V. E.; Van Doorsselaere, T.; Kuznetsov, A. A.

    2015-03-01

    We examined the polarization of the microwave flaring emission and its modulation by the fast sausage standing wave using a linear 3D magnetohydrodynamic model of a plasma cylinder. We analyzed the effects of the line-of-sight angle on the perturbations of the gyrosynchrotron intensity for two models: a base model with strong Razin suppression and a low-density model in which the Razin effect was negligible. The circular polarization (Stokes V) oscillation is in phase with the intensity oscillation, and the polarization degree (Stokes V/I) oscillates in phase with the magnetic field at the examined frequencies in both models. The two quantities experience a periodical reversal of their signs with a period equal to half of the sausage wave period when seen at a 90° viewing angle, in this case, their modulation depth reaches 100%.

  13. Climate mode simulation of North Atlantic polar lows in a limited area model

    Science.gov (United States)

    Zahn, Matthias; von Storch, Hans; Bakan, Stephan

    2008-08-01

    Polar lows are not properly resolved in global re-analyses. In order to describe the year-to-year variability and decadal trends in the formation of such mesoscale storms, atmospheric limited area models, which post-process re-analysis data, may be an appropriate tool. In this study we demonstrate the merits and potential of this approach. A series of 3-week long ensemble simulations of weather situations over the NE Atlantic with a limited area model/regional climate model (CLM) are examined. The model was driven with NCEP-NCAR re-analyses at the lateral and lower boundaries. Additionally, the spectral nudging technique was used to enforce the large-scale circulation, as given by the NCEP-NCAR reanalysis, on the simulation. The ensemble members differ by initial conditions taken from several consecutive days. In most of the cases, a polar low developed after a simulated time of about 2 weeks, that is, long after the initialization of the model calculations. The spectrally nudged version of the model is very insensitive to initial conditions. The observed polar lows were reproduced in all ensemble members. A reasonable correlation between the simulated polar low features and those derived from a satellite product (HOAPS-III) and operational high-resolution weather analyses (DWD) is found. The polar lows are considerably deepened compared to the driving NCEP-NCAR analysis, but the comparison with weather maps indicates some differences in detail. When CLM is run without the large-scale constraint of spectral nudging, considerable variability emerges across the different ensemble members and the observed polar low often does not emerge.

  14. Phase sensitivity to temperature of the guiding mode in polarization-maintaining photonic crystal fiber.

    Science.gov (United States)

    Song, Jingming; Sun, Kang; Li, Shuai; Cai, Wei

    2015-08-20

    The propagating phase changing of a polarization-maintaining photonic crystal fiber (PM-PCF) caused by temperature variation is theoretically studied, as well as compared with conventional PANDA fiber. As to verifying numerical analysis, a platform based on a Michelson interferometer for phase versus temperature measurement was built for both kinds of fiber. Experiments show that PM-PCF has similar temperature sensitivity with conventional polarization-maintaining fiber. With optimized PM-PCF design (thinner coating layer and coating material with smaller thermal expansion coefficient), the sensitivity could be further reduced to about 80% of the present level.

  15. Spatially and spectrally resolved ultra-narrowband TE-polarization absorber based on the guide-mode resonance

    Science.gov (United States)

    Liao, Yan-Lin; Zhao, Yan; Zhang, Xingfang; Zhang, Wen; Wang, Zhongzhu

    2017-08-01

    A spatially and spectrally resolved ultra-narrowband absorber with a dielectric grating and metal substrate has been reported. The absorber shows that the absorption rate is more than 0.99 with the absorption bandwidth less than 1.5 nm at normal incidence for TE polarization (electric field is parallel to grating grooves). The angular width of the absorption is about 0.27∘. The wavelength-angle sensitivity and absorption-angle sensitivity are 13.4 nm per degree and 296.3% per degree, respectively. The simulation results also show the spatially and spectrally resolved ultra-narrowband absorption is originated from the guide-mode resonance. In addition, the wavelength-angle sensitivity can be improved by enlarging the grating period according to the guide-mode resonance mechanism. The proposed absorber has potential applications in optical filters, angle measurement and thermal emitters.

  16. Space-Variant Post-Filtering for Wavefront Curvature Correction in Polar-Formatted Spotlight-Mode SAR Imagery

    Energy Technology Data Exchange (ETDEWEB)

    DOREN,NEALL E.

    1999-10-01

    Wavefront curvature defocus effects occur in spotlight-mode SAR imagery when reconstructed via the well-known polar-formatting algorithm (PFA) under certain imaging scenarios. These include imaging at close range, using a very low radar center frequency, utilizing high resolution, and/or imaging very large scenes. Wavefront curvature effects arise from the unrealistic assumption of strictly planar wavefronts illuminating the imaged scene. This dissertation presents a method for the correction of wavefront curvature defocus effects under these scenarios, concentrating on the generalized: squint-mode imaging scenario and its computational aspects. This correction is accomplished through an efficient one-dimensional, image domain filter applied as a post-processing step to PF.4. This post-filter, referred to as SVPF, is precalculated from a theoretical derivation of the wavefront curvature effect and varies as a function of scene location. Prior to SVPF, severe restrictions were placed on the imaged scene size in order to avoid defocus effects under these scenarios when using PFA. The SVPF algorithm eliminates the need for scene size restrictions when wavefront curvature effects are present, correcting for wavefront curvature in broadside as well as squinted collection modes while imposing little additional computational penalty for squinted images. This dissertation covers the theoretical development, implementation and analysis of the generalized, squint-mode SVPF algorithm (of which broadside-mode is a special case) and provides examples of its capabilities and limitations as well as offering guidelines for maximizing its computational efficiency. Tradeoffs between the PFA/SVPF combination and other spotlight-mode SAR image formation techniques are discussed with regard to computational burden, image quality, and imaging geometry constraints. It is demonstrated that other methods fail to exhibit a clear computational advantage over polar-formatting in conjunction

  17. Sub-100 fs pulses from an all-polarization maintaining Yb-fiber oscillator with an anomalous dispersion higher-order-mode fiber

    DEFF Research Database (Denmark)

    Verhoef, A. J.; Zhu, L.; Israelsen, Stine Møller

    2015-01-01

    We present an Yb-fiber oscillator with an all-polarizationmaintaining cavity with a higher-order-mode fiber for dispersion compensation. The polarization maintaining higher order mode fiber introduces not only negative second order dispersion but also negative third order dispersion in the cavity...

  18. Theory of nonlinear s-polarized plasmon-polariton and phonon-polariton modes in dielectric superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Baher, S. [Department of Physics, Lorestan University, Khoramabad (Iran, Islamic Republic of) and Research Institute of Applied Sciences (ACECR), Shahid Beheshti University (Iran, Islamic Republic of)]. E-mail: bahersalar@yahoo.com; Baharvand, A. [Department of Physics, Lorestan University, Khoramabad (Iran, Islamic Republic of); Sepahvand, R. [Department of Physics, Lorestan University, Khoramabad (Iran, Islamic Republic of); Badraghi, J. [Research Institute of Applied Sciences (ACECR), Shahid Beheshti University (Iran, Islamic Republic of)

    2007-04-30

    The propagation of nonlinear s-polarized polariton waves (TE modes) in an infinitely extended superlattice is considered. The periodic system is composed of two different components where the layers are arranged in an alternating fashion so that each layer of material 1 is bounded by two layers of material 2 and vice versa. In general, each of the individual layers may be characterized by a Kerr-type nonlinear dielectric function with a frequency-dependent characteristic of either the plasmons in a metal/semiconductor or the optical phonons in an ionic crystal. To investigate the propagation of polariton modes in such a system, a theoretical model is formulated leading to Jacobi elliptic functions for the electric field amplitude across the layers. Subsequently, the application of boundary conditions at the interfaces gives rise to dispersion relations. Numerical examples are given for plasmon-polariton and phonon-polariton modes and a comparison is made with phonon-polariton modes propagating in a three layered system.

  19. High-power Yb-fiber comb with feed-forward control of nonlinear-polarization-rotation mode-locking and large-mode-area fiber amplification.

    Science.gov (United States)

    Yan, Ming; Li, Wenxue; Yang, Kangwen; Zhou, Hui; Shen, Xuling; Zhou, Qian; Ru, Qitian; Bai, Dongbi; Zeng, Heping

    2012-05-01

    We report on a simple scheme to precisely control carrier-envelope phase of a nonlinear-polarization-rotation mode-locked self-started Yb-fiber laser system with an average output power of ∼7  W and a pulse width of 130 fs. The offset frequency was locked to the repetition rate of ∼64.5  MHz with a relative linewidth of ∼1.4  MHz by using a self-referenced feed-forward scheme based on an acousto-optic frequency shifter. The phase noise and timing jitter were calculated to be 370 mrad and 120 as, respectively.

  20. Numerical investigation of polarization insensitive two-mode division (De)multiplexer based on an asymmetric directional coupler

    Science.gov (United States)

    Truong, Cao Dung; Trinh, M. Tuan; Dang, Hoai Bac; Nguyen, Van Tho

    2017-02-01

    We propose a polarization insensitive two-mode division (de)multiplexer based on a silicon-on-insulator platform operating with a broadband, low insertion and scattering loss, and small crosstalk. By using an asymmetric directional coupler, two-mode (de)multiplexing functions for both polarization TE and TM states can be realized by the numerical simulation. Simulated results using a three dimensional beam propagation method (3D-BPM) incorporated with an effective index method (EIM) show high performance of the device with an operation efficiency above 81.2% (i.e., insertion loss is less than 0.9 dB) in the range of ±5 nm around the central wavelength of 1550 nm. Fabrication tolerances also have proved suitability to current manufacture technologies for the planar waveguides. Besides a low scattering loss of the sidewall roughness and a little influence of dispersion, a small footprint can bring the device to applications of high bitrate and compact on-chip silicon photonic integrated circuits.

  1. Four-mode continuous-variables entangled state:generation from beam splitter, a parametric down-conversion and a polarizer

    Institute of Scientific and Technical Information of China (English)

    Kuang Mai-Hua; Ma Shan-Jun; Liu Dong-Mei; Wang Shu-Jing

    2009-01-01

    We introduce a new kind of four-mode continuous variable entangled state in Fock space. The completeness relation and the partly nonorthonormal property of such a state are proven. The scheme to generate this state is presented by combining a symmetrical beamsplitter, a parametric down-conversion and a polarizer. After making a single-mode quadrature amplitude measurement, the remaining three modes are kept in entanglement. And its applications are also discussed.

  2. Measurements of the Temperature and E-Mode Polarization of the CMB from 500 Square Degrees of SPTpol Data

    Energy Technology Data Exchange (ETDEWEB)

    Henning, J.W.; et al.

    2017-07-28

    We present measurements of the $E$-mode polarization angular auto-power spectrum ($EE$) and temperature-$E$-mode cross-power spectrum ($TE$) of the cosmic microwave background (CMB) using 150 GHz data from three seasons of SPTpol observations. We now report the $EE$ and $TE$ power spectra over the spherical harmonic multipole range $50 < \\ell \\leq 8000$, and detect the first nine acoustic peaks in the $EE$ spectrum with high signal-to-noise. These measurements are the most sensitive to date of the $EE$ and $TE$ angular polarization power spectra at $\\ell > 1050$ and $\\ell > 1475$, respectively. The observations cover $500\\, \\rm{deg}^2$ of sky, a fivefold increase in area compared to previous SPTpol power spectrum releases, leading to more than a factor of two reduction in bandpower uncertainties. The additional sky coverage increases our sensitivity to the photon-diffusion damping tail of the CMB angular power spectra, which enables tighter constraints on $\\Lambda CDM$ model extensions such as primordial helium content $Y_\\rm{p}$ and effective number of relativistic species $N_\\rm{eff}$. Furthermore, after masking all sources with unpolarized flux $>50$ mJy we place a 95% confidence upper limit on residual polarized point-source power of $D_\\ell < 0.10 \\mu{\\rm K}^2$ at $\\ell=3000$. This limit is a factor of four lower than the previous best upper limit, and suggests that the $EE$ damping tail is brighter than foregrounds to at least $\\ell = 4100$ with modest source masking. Finally, we find cosmological parameter constraints consistent with those for $Planck$ temperature when fitting SPTpol data at $\\ell < 1000$. However, including SPTpol data at $\\ell > 1000$ results in a preference for a higher value of the expansion rate ($H_0 = 71.2 \\pm 2.1\\,\\mbox{km}\\,s^{-1}\\mbox{Mpc}^{-1}$) and a lower value for present-day density fluctuations ($\\sigma_8 = 0.77 \\pm 0.02$). (Abridged).

  3. Fundamental and high-order anapoles in all-dielectric metamaterials via Fano–Feshbach modes competition

    KAUST Repository

    Gongora, J. S. Totero

    2017-02-01

    One of the most fascinating possibilities enabled by metamaterials is the strong reduction of the electromagnetic scattering from nanostructures. In dielectric nanoparticles, the formation of a minimal scattering state at specific wavelengths is associated with the excitation of photonic anapoles, which represent a peculiar type of radiationless state and whose existence has been demonstrated experimentally. In this work, we investigate the formation of anapole states in generic dielectric structures by applying a Fano-Feshbach projection scheme, a general technique widely used in the study of quantum mechanical open systems. By expressing the total scattering from the structure in terms of an orthogonal set of internal and external modes, defined in the interior and in the exterior of the dielectric structure, respectively, we show how anapole states are the result of a complex interaction among the resonances of the system and the surrounding environment. We apply our approach to a circular resonator, where we observe the formation of higher-order anapole states, which are originated by the superposition of several internal resonances of the system.

  4. Spectroscopic monitoring of the Herbig Ae star HD 104237. II. Non-radial pulsations, mode analysis and fundamental stellar parameters

    CERN Document Server

    Fumel, Aurelie

    2011-01-01

    Herbig Ae/Be stars are intermediate-mass pre-main sequence (PMS) stars showing signs of intense activity and strong stellar winds, whose origin is not yet understood in the frame of current theoretical models of stellar evolution for young stars. The evolutionary tracks of the earlier Herbig Ae stars cross a recently discovered PMS instability strip. Many of these stars exhibit pulsations of delta Scuti type. HD 104237 is a well-known pulsating Herbig Ae star. In this article, we reinvestigated an extensive high-resolution quasi-continuous spectroscopic data set in order to search for very faint indications of non-radial pulsations in the line profile. To do this, we worked on dynamical spectra of equivalent photospheric (LSD) profiles of HD 104237. A 2D Fourier analysis (F2D) was performed of the entire profile and the temporal variation of the central depth of the line was studied with the time-series analysis tools Period04 and SigSpec. We present a mode identification corresponding to the detected dominan...

  5. Fundamental ecology is fundamental.

    Science.gov (United States)

    Courchamp, Franck; Dunne, Jennifer A; Le Maho, Yvon; May, Robert M; Thébaud, Christophe; Hochberg, Michael E

    2015-01-01

    The primary reasons for conducting fundamental research are satisfying curiosity, acquiring knowledge, and achieving understanding. Here we develop why we believe it is essential to promote basic ecological research, despite increased impetus for ecologists to conduct and present their research in the light of potential applications. This includes the understanding of our environment, for intellectual, economical, social, and political reasons, and as a major source of innovation. We contend that we should focus less on short-term, objective-driven research and more on creativity and exploratory analyses, quantitatively estimate the benefits of fundamental research for society, and better explain the nature and importance of fundamental ecology to students, politicians, decision makers, and the general public. Our perspective and underlying arguments should also apply to evolutionary biology and to many of the other biological and physical sciences. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  6. Double-pass high-gain low-noise EDFA over S- and C+L-bands by tunable fundamental-mode leakage loss.

    Science.gov (United States)

    Hung, Chi-Ming; Chen, Nan-Kuang; Lai, Yinchieh; Chi, Sien

    2007-02-19

    We demonstrate a high-gain low-noise double-pass tunable EDFA over S- and C+L-bands by discretely introducing fundamental-mode leakage loss in a 16-m-long standard C-band Er(3+)-doped fiber. The amplified spontaneous emission at the wavelengths of longer than 1530 nm can be substantially attenuated by the ASE suppressing filters to maintain high population inversion and to squeeze out the optical gain for S-band signals. When the filters are disabled, the gain bandwidth immediately returns back to the C+L-bands. Under S-band operation, a 37 dB small signal gain and a minimum 4.84 dB noise figure at 1486.9 nm are achieved with a 980 nm pump power of 154 mW.

  7. Multiwavelength mode-locked cylindrical vector beam fiber laser based on mode selective coupler

    Science.gov (United States)

    Huang, Ping; Cai, Yu; Wang, Jie; Wan, Hongdan; Zhang, Zuxing; Zhang, Lin

    2017-10-01

    We propose and demonstrate a multiwavelength mode-locked fiber laser with cylindrical vector beam generation for the first time, to the best of our knowledge. The mode-locking mechanism is based on a nonlinear polarization rotation effect in fiber, and the multiwavelength operation is contributed to by an in-line birefringence fiber filter with periodic multiple passbands, formed by incorporating a section of polarization maintaining fiber into the laser cavity with a fiber polarizer. Furthermore, by using a home-made mode selective coupler, which acts as both a mode converter from fundamental mode to higher-order mode and an output coupler, multiwavelength mode-locked cylindrical vector beams have been obtained. This may have potential applications in mode-division multiplexing optical fiber communication and material processing.

  8. Characterization of lemon (Citrus limon) polar extract by liquid chromatography-tandem mass spectrometry in high resolution mode.

    Science.gov (United States)

    Ledesma-Escobar, C A; Priego-Capote, F; Luque de Castro, M D

    2015-11-01

    Eighty four metabolites (32 flavonoids, 15 amino acids, nine carboxylic acids, six coumarins, six sugars, five phenolic acids and 11 unclassified compounds) have been tentatively identified in a polar extract from lemon, without reference standards, based on their liquid chromatography-quadrupole-time-of-flight MS/MS spectra and the comparison with databases. Despite information in databases for some families of plant compounds is poor, tentative identification based on MS/MS information (mass of the precursor ion and their fragments, together with neutral mass loss) was possible with the help of known fragmentation patterns for the given families of compounds. Both positive and negative ionization modes and at least two collision energies were always applied to obtain as much information as possible from each molecular entity, thus helping for identification. As the tentatively identified metabolites are the same regardless of the organism they belong, their fragmentation patterns are useful for identification with independence of the sample nature.

  9. Development of Optical Voltage Transducer Based on Dual-Mode Highly Elliptical-Core Polarization Maintenance Fiber

    Institute of Scientific and Technical Information of China (English)

    Wei-Hong Bi; Feng Liu; Xuan Guo

    2008-01-01

    This paper describes an optical voltage transducer (OVT) for the 35 kV electric power system based on modular interference in dual-mode highly elliptical-core polarization maintenance fiber (E-Core PMIF). The temperature and environmental perturb-bation can be compensated automatically. In the scheme, a quartz crystal cylinder wrapped with highly elliptical-core fiber plays the role of voltage sensor head. The two interference output lobes' intensity from the E-core PMF is modulated with the converse piezoelectric effect of quartz crystal. A PZT wrapped with E-core PMF at ground potential serves as the static modular phase difference control and temperature compensation unit. The experiment results indicate that the OVT designed in this paper has satisfying performance and could successfully rejects the temperature perturbation.

  10. Impact of Polarization Mode Dispersion on Transmission Characteristics of Dispersion-Managed Solitons and Its Suppression

    Institute of Scientific and Technical Information of China (English)

    杨祥林; 徐铭; 蔡炬

    2003-01-01

    The coupled nonlinear Schrodinger equations for dispersion-managed soliton (DMS) with the impact of thepolarization mode dispersion (PMD) are constructed, and a PMD-suppression approach of DMS is proposed for the first time. Then, based on variational method, the analytical equations of the DMS transmission system within-line optical filter control are obtained. Finally, in order to investigate the validity of the equations, we presentan application sample for practical systems with in-line filter control. The results verify that the control is quiteeffective and valid.

  11. CMB B-mode Polarization Measurements and constraints on Primordial Gravitational Waves from the BICEP/Keck Program at South Pole

    Science.gov (United States)

    Kovac, John; Bicep/Keck Collaboration

    2017-01-01

    The BICEP/Keck Array cosmic microwave background (CMB) polarization experiments located at the South Pole are a series of small-aperture refracting telescopes designed to probe the degree-scale B-mode signature of primordial gravitational waves. These highly-targeted experiments have produced the world's deepest maps of CMB polarization, leading to the most stringent constraints on the tensor-to-scalar ratio to date: r r r < 0 . 01 and below within the next several years.

  12. Switchable Dual-Wavelength Mode-Locked Er-Doped Fibre Laser Using a Bragg Grating in Polarization-Maintaining Fibre

    Institute of Scientific and Technical Information of China (English)

    FENG Xin-Huan; LIU Yan-Ge; SUN Lei; XIONG Ling-Yun; LI-Yao; YUAN Shu-Zhong; KAI Gui-Yun; DONG Xiao-Yi

    2004-01-01

    @@ A simple actively mode-locked fibre ring laser is proposed and successfully demonstrated to generate switchable dual-wavelength picosecond pulses using a Bragg grating in a polarization-maintaining fibre. The wavelength spacing specified by the grating is only 0.52nm. The proposed laser can be made to operate in stable dualwavelength or switch between wavelengths at room temperature, only by simple adjustment of a polarization controller.

  13. Making maps of Cosmic Microwave Background polarization for B-mode studies: the POLARBEAR example

    CERN Document Server

    Poletti, Davide; Jeune, Maude Le; Peloton, Julien; Arnold, Kam; Baccigalupi, Carlo; Barron, Darcy; Beckman, Shawn; Borrill, Julian; Chapman, Scott; Chinone, Yuji; Cukierman, Ari; Ducout, Anne; Elleflot, Tucker; Errard, Josquin; Feeney, Stephen; Goeckner-Wald, Neil; Groh, John; Hall, Grantland; Hasegawa, Masaya; Hazumi, Masashi; Hill, Charles; Howe, Logan; Inoue, Yuki; Jaffe, Andrew H; Jeong, Oliver; Katayama, Nobuhiko; Keating, Brian; Keskitalo, Reijo; Kisner, Theodore; Kusaka, Akito; Lee, Adrian T; Leon, David; Linder, Eric; Lowry, Lindsay; Matsuda, Frederick; Navaroli, Martin; Paar, Hans; Puglisi, Giuseppe; Reichardt, Christian L; Ross, Colin; Siritanasak, Praween; Stebor, Nathan; Steinbach, Bryan; Stompor, Radek; Suzuki, Aritoki; Tajima, Osamu; Teply, Grant; Whitehorn, Nathan

    2016-01-01

    Analysis of cosmic microwave background (CMB) datasets typically requires some filtering of the raw time-ordered data. Filtering is frequently used to minimize the impact of low frequency noise, atmospheric contributions and/or scan synchronous signals on the resulting maps. In this work we explicitly construct a general filtering operator, which can unambiguously remove any set of unwanted modes in the data, and then amend the map-making procedure in order to incorporate and correct for it. We show that such an approach is mathematically equivalent to the solution of a problem in which the sky signal and unwanted modes are estimated simultaneously and the latter are marginalized over. We investigate the conditions under which this amended map-making procedure can render an unbiased estimate of the sky signal in realistic circumstances. We then study the effects of time-domain filtering on the noise correlation structure in the map domain, as well as impact it may have on the performance of the popular pseudo...

  14. Mode Coupling between the Nonpolar K3 and Polar Γ2-Phonons as the Ferroelectricity Origin of Multiferroic h-LuMnO3

    Science.gov (United States)

    Song, Seungwoo; Heo, Seungyang; Jang, Hyun Myung

    2014-03-01

    LuMnO3 is expected to show the highest stability towards the hexagonal phase among 15 different lanthanide-based manganites. Currently, the most puzzling problem associated with the hexagonal LuMnO3 (h-LMO) is the observed large temperature-gap between the structural phase transition to the polar P63cm phase at ~ 1290 K and the emergence of the spontaneous polarization at a substantially reduced temperature, ~ 750 K. This anomalous temperature-gap has also been observed in h-YMnO3. To resolve this puzzling issue, we have carried out density-functional theory calculations and found that the structural phase transition to the polar P63 cm phase from the nonpolar P63/mmc phase is mediated by the freezing-in of the zone-boundary K3 phonon in h-LMO. However, the spontaneous ferroelectric polarization does not appear until the amplitude of K3 phonon becomes a certain critical value above which the coupling of the polar Γ2-mode with the nonpolar K3 mode is practically turned on. This mode-coupling-induced polarization, thus, elucidates the above puzzle.

  15. Calculating the contribution of different binding modes to Quinacrine - DNA complex formation from polarized fluorescence data

    CERN Document Server

    Voloshin, Igor; Karachevtsev, Victor; Zozulya, Victor

    2013-01-01

    Binding of acridine derivative quinacrine (QA) to chicken erythrocyte DNA was studied by methods of absorption and polarized fluorescent spectroscopy. Measurements were carried out in aqueous buffered solutions (pH 6.9) of different dye concentrations (QA concentration range from $10^{-6}$ till $10^{-4}$ M) and ionic strengths ($Na^{+}$ concentration rang from $10^{-3}$ till 0.15 M) in a wide range of phosphate-to-dye molar ratios ($P/D$). It is established that the minimum of fluorescent titration curve plotted as relative fluorescence intensity $vs$ $P/D$ is conditioned by the competition between the two types of QA binding to DNA which posses by different emission parameters: (i) intercalative one dominating under high $P/D$ values, and (ii) outside electrostatic binding dominating under low $P/D$ values, which is accompanied by the formation of non-fluorescent dye associates on the DNA backbone. Absorption and fluorescent characteristics of complexes formed were determined. The method of calculation of di...

  16. Dynamics of centrosome translocation and microtubule organization in neocortical neurons during distinct modes of polarization.

    Science.gov (United States)

    Sakakibara, Akira; Sato, Toshiyuki; Ando, Ryota; Noguchi, Namiko; Masaoka, Makoto; Miyata, Takaki

    2014-05-01

    Neuronal migration and process formation require cytoskeletal organization and remodeling. Recent studies suggest that centrosome translocation is involved in initial axon outgrowth, while the role of centrosomal positioning is not clear. Here, we examine relations between centrosomal positioning, axonogenesis, and microtubule (MT) polarization in multipolar and bipolar neocortical neurons. We monitored dynamic movements of centrosomes and MT plus ends in migratory neurons in embryonic mouse cerebral slices. In locomoting bipolar neurons, the centrosome oriented toward the pia-directed leading process. Bipolar neurons displayed dense MT plus end dynamics in leading processes, while trailing processes showed clear bidirectional MTs. In migrating multipolar neurons, new processes emerged irrespective of centrosome localization, followed by centrosome reorientations toward the dominant process. Anterograde movements of MT plus ends occurred in growing processes and retrograde movements were observed after retraction of the distal tip. In multipolar neurons, axon formed by tangential extension of a dominant process and the centrosome oriented toward the growing axon, while in locomoting neurons, an axon formed opposite to the direction of migration and the centrosome localized to the base of the leading process. Our data suggest that MT organization may alter centrosomal localization and that centrosomal positioning does not necessarily direct process formation.

  17. Fundamentally updating fundamentals.

    Science.gov (United States)

    Armstrong, Gail; Barton, Amy

    2013-01-01

    Recent educational research indicates that the six competencies of the Quality and Safety Education for Nurses initiative are best introduced in early prelicensure clinical courses. Content specific to quality and safety has traditionally been covered in senior level courses. This article illustrates an effective approach to using quality and safety as an organizing framework for any prelicensure fundamentals of nursing course. Providing prelicensure students a strong foundation in quality and safety in an introductory clinical course facilitates early adoption of quality and safety competencies as core practice values.

  18. Hybrid plasmonic gap modes in metal film-coupled dimers and their physical origins revealed by polarization resolved dark field spectroscopy

    Science.gov (United States)

    Li, Guang-Can; Zhang, Yong-Liang; Lei, Dang Yuan

    2016-03-01

    Plasmonic gap modes sustained by metal film-coupled nanostructures have recently attracted extensive research attention due to flexible control over their spectral response and significantly enhanced field intensities at the particle-film junction. In this work, by adopting an improved dark field spectroscopy methodology - polarization resolved spectral decomposition and colour decoding - we are able to ``visualize'' and distinguish unambiguously the spectral and far field radiation properties of the complex plasmonic gap modes in metal film-coupled nanosphere monomers and dimers. Together with full-wave numerical simulation results, it is found that while the monomer-film system supports two hybridized dipole-like plasmon modes having different oscillating orientations and resonance strengths, the scattering spectrum of the dimer-film system features two additional peaks, one strong yet narrow resonant mode corresponding to a bonding dipolar moment and one hybridized higher order resonant mode, both polarized along the dimer axis. In particular, we demonstrate that the polarization dependent scattering radiation of the film-coupled nanosphere dimer can be used to optically distinguish from monomers and concurrently determine the spatial orientation of the dimer with significantly improved accuracy at the single-particle level, illustrating a simple yet highly sensitive plasmon resonance based nanometrology method.Plasmonic gap modes sustained by metal film-coupled nanostructures have recently attracted extensive research attention due to flexible control over their spectral response and significantly enhanced field intensities at the particle-film junction. In this work, by adopting an improved dark field spectroscopy methodology - polarization resolved spectral decomposition and colour decoding - we are able to ``visualize'' and distinguish unambiguously the spectral and far field radiation properties of the complex plasmonic gap modes in metal film

  19. Polarized infrared reflectance spectra of brushite (CaHPO4·2H2O) crystal investigation of the phosphate stretching modes.

    Science.gov (United States)

    Mevellec, Jean-Yves; Quillard, Sophie; Deniard, Philippe; Mekmene, Omar; Gaucheron, Frédéric; Bouler, Jean-Michel; Buisson, Jean-Pierre

    2013-07-01

    Polarized infrared (IR) reflectance measurements at near-normal incidence were recorded from the ac-plane of a monoclinic brushite (CaHPO4·2H2O) crystal in the 800-1200 cm(-1) spectral range (P-O stretching modes). The adjustment of these data, on the basis of a dispersion analysis (DA) model for monoclinic case, allowed the determination of oscillators parameters for the four P-O stretching observed modes of the phosphate group.

  20. Polarized infrared reflectance spectra of brushite (CaHPO4ṡ2H2O) crystal investigation of the phosphate stretching modes

    Science.gov (United States)

    Mevellec, Jean-Yves; Quillard, Sophie; Deniard, Philippe; Mekmene, Omar; Gaucheron, Frédéric; Bouler, Jean-Michel; Buisson, Jean-Pierre

    2013-07-01

    Polarized infrared (IR) reflectance measurements at near-normal incidence were recorded from the ac-plane of a monoclinic brushite (CaHPO4ṡ2H2O) crystal in the 800-1200 cm-1 spectral range (P-O stretching modes). The adjustment of these data, on the basis of a dispersion analysis (DA) model for monoclinic case, allowed the determination of oscillators parameters for the four P-O stretching observed modes of the phosphate group.

  1. Pygmy and core polarization dipole modes in 206Pb: Connecting nuclear structure to stellar nucleosynthesis

    Science.gov (United States)

    Tonchev, A. P.; Tsoneva, N.; Bhatia, C.; Arnold, C. W.; Goriely, S.; Hammond, S. L.; Kelley, J. H.; Kwan, E.; Lenske, H.; Piekarewicz, J.; Raut, R.; Rusev, G.; Shizuma, T.; Tornow, W.

    2017-10-01

    A high-resolution study of the electromagnetic response of 206Pb below the neutron separation energy is performed using a (γ → ,γ‧) experiment at the HI γ → S facility. Nuclear resonance fluorescence with 100% linearly polarized photon beams is used to measure spins, parities, branching ratios, and decay widths of excited states in 206Pb from 4.9 to 8.1 MeV. The extracted ΣB (E 1) ↑ and ΣB (M 1) ↑ values for the total electric and magnetic dipole strength below the neutron separation energy are 0.9 ± 0.2 e2fm2 and 8.3 ± 2.0 μN2, respectively. These measurements are found to be in very good agreement with the predictions from an energy-density functional (EDF) plus quasiparticle phonon model (QPM). Such a detailed theoretical analysis allows to separate the pygmy dipole resonance from both the tail of the giant dipole resonance and multi-phonon excitations. Combined with earlier photonuclear experiments above the neutron separation energy, one extracts a value for the electric dipole polarizability of 206Pb of αD = 122 ± 10 mb /MeV. When compared to predictions from both the EDF+QPM and accurately calibrated relativistic EDFs, one deduces a range for the neutron-skin thickness of Rskin206 = 0.12- 0.19 fm and a corresponding range for the slope of the symmetry energy of L = 48- 60 MeV. This newly obtained information is also used to estimate the Maxwellian-averaged radiative cross section 205Pb (n , γ)206Pb at 30 keV to be σ = 130 ± 25 mb. The astrophysical impact of this measurement-on both the s-process in stellar nucleosynthesis and on the equation of state of neutron-rich matter-is discussed.

  2. Phase-polarization parallax barriers for an autostereo/stereo/monoscopic display with full-screen resolution at each operation mode.

    Science.gov (United States)

    Ezhov, Vasily

    2015-10-01

    It is attractive to have a three-mode flat-panel 3D display capable of working in autostereoscopic, stereoscopic-with-passive-glasses, and monoscopic modes and providing full-screen resolution of images at each mode. The concept of autostereoscopic displays simultaneously reproducing two image elements in each display pixel based on information-dependent polarization coding and subsequent decoding was recently proposed. Such a concept allows full-screen resolution in each image view and flickerless 3D images to be observed even at a 60-Hz frame rate. The essential problem of such display implementation is to create the suitable structure of the phase-polarization parallax barrier (PPPB) capable of working properly at a variable polarization state of input light. This paper presents the results of theoretical research of an electrically switchable liquid crystal (LC) PPPB. The Jones matrix notation of the required performance function of the LC PPPB is found. The results of computer modeling of achromatic characteristics of suitable LC structures are discussed to determine the optimum structures for PPPB. The proposed layout of three-mode 3D display with LC PPPB allows it to go from autostereoscopic mode to "stereoscopic-with-passive-glasses" mode and backward by electrical switching the LC PPPB in combination with removing/inserting the output polaroid film.

  3. Pygmy and core polarization dipole modes in 206 Pb: Connecting nuclear structure to stellar nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Tonchev, A. P.; Tsoneva, N.; Bhatia, C.; Arnold, C. W.; Goriely, S.; Hammond, S. L.; Kelley, J. H.; Kwan, E.; Lenske, H.; Piekarewicz, J.; Raut, R.; Rusev, G.; Shizuma, T.; Tornow, W.

    2017-10-01

    A high-resolution study of the electromagnetic response of 206Pb below the neutron separation energy is performed using a (γ→,γ') experiment at the HIγ→S facility. Nuclear resonance fluorescence with 100% linearly polarized photon beams is used to measure spins, parities, branching ratios, and decay widths of excited states in 206Pb from 4.9 to 8.1 MeV. The extracted ΣB(E1)↑ and ΣB(M1)↑ values for the total electric and magnetic dipole strength below the neutron separation energy are 0.9±0.2e2fm2 and 8.3±2.0μ$2\\atop{N}$, respectively. These measurements are found to be in very good agreement with the predictions from an energy-density functional (EDF) plus quasiparticle phonon model (QPM). Such a detailed theoretical analysis allows to separate the pygmy dipole resonance from both the tail of the giant dipole resonance and multi-phonon excitations. Combined with earlier photonuclear experiments above the neutron separation energy, one extracts a value for the electric dipole polarizability of 206Pb of αD=122±10mb/MeV. When compared to predictions from both the EDF+QPM and accurately calibrated relativistic EDFs, one deduces a range for the neutron-skin thickness of R$206\\atop{skin}$=0.12–0.19fm and a corresponding range for the slope of the symmetry energy of L=48–60MeV. This newly obtained information is also used to estimate the Maxwellian-averaged radiative cross section 205Pb(n,γ)Pb206 at 30 keV to be σ=130±25mb. The astrophysical impact of this measurement—on both the s-process in stellar nucleosynthesis and on the equation of state of neutron-rich matter—is discussed.

  4. Planck intermediate results. XXXVIII. $E$- and $B$-modes of dust polarization from the magnetized filamentary structure of the interstellar medium

    CERN Document Server

    Ade, P A R; Arnaud, M; Ashdown, M; Aumont, J; Baccigalupi, C; Banday, A J; Barreiro, R B; Bartolo, N; Battaner, E; Benabed, K; Benoit-Lévy, A; Bernard, J -P; Bersanelli, M; Bielewicz, P; Bonaldi, A; Bonavera, L; Bond, J R; Borrill, J; Bouchet, F R; Boulanger, F; Bracco, A; Burigana, C; Calabrese, E; Cardoso, J -F; Catalano, A; Chamballu, A; Chary, R -R; Chiang, H C; Christensen, P R; Colombo, L P L; Combet, C; Crill, B P; Curto, A; Cuttaia, F; Danese, L; Davies, R D; Davis, R J; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J -M; Dickinson, C; Diego, J M; Dole, H; Donzelli, S; Doré, O; Douspis, M; Dunkley, J; Dupac, X; Efstathiou, G; Elsner, F; Enßlin, T A; Eriksen, H K; Falgarone, E; Ferrière, K; Finelli, F; Forni, O; Frailis, M; Fraisse, A A; Franceschi, E; Frolov, A; Galeotta, S; Galli, S; Ganga, K; Ghosh, T; Giard, M; Gjerløw, E; González-Nuevo, J; Górski, K M; Gruppuso, A; Guillet, V; Hansen, F K; Harrison, D L; Helou, G; Hernández-Monteagudo, C; Herranz, D; Hildebrandt, S R; Hivon, E; Hornstrup, A; Hovest, W; Huang, Z; Huffenberger, K M; Hurier, G; Jaffe, T R; Jones, W C; Juvela, M; Keihänen, E; Keskitalo, R; Kisner, T S; Kneissl, R; Knoche, J; Kunz, M; Kurki-Suonio, H; Lamarre, J -M; Lasenby, A; Lattanzi, M; Lawrence, C R; Leonardi, R; León-Tavares, J; Levrier, F; Liguori, M; Lilje, P B; Linden-Vørnle, M; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; Maffei, B; Maino, D; Mandolesi, N; Maris, M; Martin, P G; Martínez-González, E; Masi, S; Matarrese, S; McGehee, P; Melchiorri, A; Mennella, A; Migliaccio, M; Miville-Deschênes, M -A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, J A; Naselsky, P; Nati, F; Natoli, P; Novikov, D; Novikov, I; Oppermann, N; Oxborrow, C A; Pagano, L; Pajot, F; Paoletti, D; Pasian, F; Perdereau, O; Pettorino, V; Piacentini, F; Piat, M; Pierpaoli, E; Plaszczynski, S; Pointecouteau, E; Polenta, G; Ponthieu, N; Pratt, G W; Prunet, S; Puget, J -L; Rachen, J P; Reach, W T; Rebolo, R; Reinecke, M; Remazeilles, M; Renault, C; Renzi, A; Ristorcelli, I; Rocha, G; Rosset, C; Rossetti, M; Roudier, G; Rubiño-Martín, J A; Rusholme, B; Sandri, M; Santos, D; Savelainen, M; Savini, G; Scott, D; Serra, P; Soler, J D; Stolyarov, V; Sudiwala, R; Sunyaev, R; Suur-Uski, A -S; Sygnet, J -F; Tauber, J A; Terenzi, L; Toffolatti, L; Tomasi, M; Tristram, M; Tucci, M; Umana, G; Valenziano, L; Valiviita, J; Van Tent, B; Vielva, P; Villa, F; Wade, L A; Wandelt, B D; Wehus, I K; Yvon, D; Zacchei, A; Zonca, A

    2015-01-01

    The quest for a $B$-mode imprint from primordial gravity waves on the polarization of the cosmic microwave background (CMB) requires the characterization of foreground polarization from Galactic dust. We present a statistical study of the filamentary structure of the $353\\,$GHz Planck Stokes maps at high Galactic latitude, relevant to the study of dust emission as a polarized foreground to the CMB. We filter the intensity and polarization maps to isolate filaments in the range of angular scales where the power asymmetry between $E$-modes and $B$-modes is observed. Using the Smoothed Hessian Major Axis Filament Finder, we identify 259 filaments at high Galactic latitude, with lengths larger or equal to $2$\\deg\\ (corresponding to $3.5\\,$pc in length for a typical distance of $100\\,$pc). These filaments show a preferred orientation parallel to the magnetic field projected onto the plane of the sky, derived from their polarization angles. We present mean maps of the filaments in Stokes $I$, $Q$, $U$, $E$, and $B$...

  5. Information Leakage Problem in Efficient Bidirectional Quantum Secure Direct Communication with Single Photons in Both Polarization and Spatial-Mode Degrees of Freedom

    Science.gov (United States)

    Liu, Zhi-Hao; Chen, Han-Wu; Liu, Wen-Jie

    2016-11-01

    The information leakage problem in the efficient bidirectional quantum secure direct communication protocol with single photons in both polarization and spatial-mode degrees of freedom is pointed out. Next, a way to revise this protocol to a truly secure one is given. We hope people pay more attention to the information leakage problem in order to design truly secure quantum communication protocols.

  6. Entanglement of Vector-Polarization States of Photons

    CERN Document Server

    Kong, Ling-Jun; Si, Yu; Liu, Rui; Wang, Zhou-Xiang; Tu, Chenghou; Wang, Hui-Tian

    2015-01-01

    Photons may have homogeneous polarization and may carry quantized orbital angular momentum (OAM). Photon entanglement has been realized in various degrees of freedom such as polarization and OAM. Using a pair of orthogonally polarized states carrying opposite-handedness quantized OAMs could create "quantized" vector polarization states with space-variant polarization structures. It is thus possible to extend the polarization degree of freedom from two dimensional space to indefinite dimensional discrete Hilbert space. We present a class of vector-polarization entangled Bell states, which use the spatial modes of the vector fields with space-variant polarization structure. We propose a scheme of creating the vector-polarization entangled Bell states using a Sagnac interferometer. We also design an analyzer for identifying the vector-polarization entangled Bell states. Such a class of entanglement is important for quantum information science and technology, and fundamental issues of quantum theory, due to its a...

  7. Repetition frequency scaling of an all-polarization maintaining erbium-doped mode-locked fiber laser based on carbon nanotubes saturable absorber

    Energy Technology Data Exchange (ETDEWEB)

    Sotor, J., E-mail: jaroslaw.sotor@pwr.edu.pl; Sobon, G.; Abramski, K. M. [Laser and Fiber Electronics Group, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Jagiello, J.; Lipinska, L. [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland)

    2015-04-07

    We demonstrate an all-polarization maintaining (PM), mode-locked erbium (Er)-doped fiber laser based on a carbon nanotubes (CNT) saturable absorber (SA). The laser resonator was maximally simplified by using only one passive hybrid component and a pair of fiber connectors with deposited CNTs. The repetition frequency (F{sub rep}) of such a cost-effective and self-starting mode-locked laser was scaled from 54.3 MHz to 358.6 MHz. The highest F{sub rep} was obtained when the total cavity length was shortened to 57 cm. The laser allows ultrashort pulse generation with the duration ranging from 240 fs to 550 fs. Because the laser components were based on PM fibers the laser was immune to the external perturbations and generated laniary polarized light with the degree of polarization (DOP) of 98.7%.

  8. Sub-100 fs pulses from an all-polarization maintaining Yb-fiber oscillator with an anomalous dispersion higher-order-mode fiber

    DEFF Research Database (Denmark)

    Verhoef, A.J.; Zhu, L.; Israelsen, Stine Møller;

    2015-01-01

    We present an Yb-fiber oscillator with an all-polarization-maintaining cavity with a higher-order-mode fiber for dispersion compensation. The polarization maintaining higher order mode fiber introduces not only negative second order dispersion but also negative third order dispersion in the cavity......, in contrast to dispersion compensation schemes used in previous demonstrations of all-polarization maintaining Yb-fiber oscillators. The performance of the saturable absorber mirror modelocked oscillator, that employs a free space scheme for coupling onto the saturable absorber mirror and output coupling......-fiber oscillator. The spectral phase of the output pulses is well behaved and can be compensated such that wing-free Fourier transform limited pulses can be obtained. Further reduction of the net intracavity third order dispersion will allow generating broader output spectra and consequently shorter pulses...

  9. Repetition frequency scaling of an all-polarization maintaining erbium-doped mode-locked fiber laser based on carbon nanotubes saturable absorber

    Science.gov (United States)

    Sotor, J.; Sobon, G.; Jagiello, J.; Lipinska, L.; Abramski, K. M.

    2015-04-01

    We demonstrate an all-polarization maintaining (PM), mode-locked erbium (Er)-doped fiber laser based on a carbon nanotubes (CNT) saturable absorber (SA). The laser resonator was maximally simplified by using only one passive hybrid component and a pair of fiber connectors with deposited CNTs. The repetition frequency (Frep) of such a cost-effective and self-starting mode-locked laser was scaled from 54.3 MHz to 358.6 MHz. The highest Frep was obtained when the total cavity length was shortened to 57 cm. The laser allows ultrashort pulse generation with the duration ranging from 240 fs to 550 fs. Because the laser components were based on PM fibers the laser was immune to the external perturbations and generated laniary polarized light with the degree of polarization (DOP) of 98.7%.

  10. INFLUENCE OF POLARIZATION MODE DISPERSION ON THE EFFECT OF CROSS-PHASE MODULATION IN INTENSITY MODULATION-DIRECT DETECTION WDM TRANSMISSION SYSTEM

    Directory of Open Access Journals (Sweden)

    M S Islam

    2010-03-01

    Full Text Available Cross-phase modulation (XPM changes the state-of-polarization (SOP of the channels through nonlinear polarization rotation and induces nonlinear time dependent phase shift for polarization components that leads to amplitude modulation of the propagating waves in a wavelength division multiplexing (WDM system. Due to the presence of birefringence, the angle between the SOP changes randomly and as a result polarization mode dispersion (PMD causes XPM modulation amplitude fluctuation random in the perturbed channel. In this paper we analytically determine the probability density function of the random angle between the SOP of pump and probe, and evaluate the impact of polarization mode dispersion on XPM in terms of bit error rate, channel spacing etc for a two channel intensity modulation-direct detection WDM system at 10 Gb/s. It is found that the XPM induced crosstalk is polarization independent for channel spacing greater than 3 nm or PMD coefficient larger than 2 ps/√km. We also investigate the dependence of SOP variance on PMD coefficient and channel spacing.

  11. Optimum design of phononic crystal perforated plate structures for widest bandgap of fundamental guided wave modes and maximized in-plane stiffness

    Science.gov (United States)

    Hedayatrasa, Saeid; Abhary, Kazem; Uddin, Mohammad; Ng, Ching-Tai

    2016-04-01

    This paper presents a topology optimization of single material phononic crystal plate (PhP) to be produced by perforation of a uniform background plate. The primary objective of this optimization study is to explore widest exclusive bandgaps of fundamental (first order) symmetric or asymmetric guided wave modes as well as widest complete bandgap of mixed wave modes (symmetric and asymmetric). However, in the case of single material porous phononic crystals the bandgap width essentially depends on the resultant structural integration introduced by achieved unitcell topology. Thinner connections of scattering segments (i.e. lower effective stiffness) generally lead to (i) wider bandgap due to enhanced interfacial reflections, and (ii) lower bandgap frequency range due to lower wave speed. In other words higher relative bandgap width (RBW) is produced by topology with lower effective stiffness. Hence in order to study the bandgap efficiency of PhP unitcell with respect to its structural worthiness, the in-plane stiffness is incorporated in optimization algorithm as an opposing objective to be maximized. Thick and relatively thin Polysilicon PhP unitcells with square symmetry are studied. Non-dominated sorting genetic algorithm NSGA-II is employed for this multi-objective optimization problem and modal band analysis of individual topologies is performed through finite element method. Specialized topology initiation, evaluation and filtering are applied to achieve refined feasible topologies without penalizing the randomness of genetic algorithm (GA) and diversity of search space. Selected Pareto topologies are presented and gradient of RBW and elastic properties in between the two Pareto front extremes are investigated. Chosen intermediate Pareto topology, even not extreme topology with widest bandgap, show superior bandgap efficiency compared with the results reported in other works on widest bandgap topology of asymmetric guided waves, available in the literature

  12. Linearly polarized pumped passively Q-switched Nd:YVO4 microchip laser for Ince-Gaussian laser modes with controllable orientations

    Science.gov (United States)

    He, Hong-Sen; Zhang, Ming-Ming; Dong, Jun; Ueda, Ken-Ichi

    2016-12-01

    A tilted, linearly polarized laser diode end-pumped Cr4+:YAG passively Q-switched a-cut Nd:YVO4 microchip laser for generating numerous Ince-Gaussian (IG) laser modes with controllable orientations has been demonstrated by selecting the crystalline orientation of an a-cut Nd:YVO4 crystal. The same IG laser mode with different orientations has been achieved with the same absorbed pump power in a passively Q-switched Nd:YVO4 microchip laser under linearly polarized pumping when the incident pump power and the crystalline orientation of an a-cut Nd:YVO4 crystal are both properly selected. The significant improvement of pulsed laser performance of controllable IG modes has been achieved by selecting the crystalline orientation of an a-cut Nd:YVO4 crystal. The maximum pulse energy is obtained along the a-axis of an a-cut Nd:YVO4 crystal and the highest peak power is achieved along the c-axis of an a-cut Nd:YVO4 crystal, respectively, which has potential applications on quantum computation and optical manipulation. The generation of controllable IG laser modes in microchip lasers under linearly polarized pumping provides a convenient and universal way to control IG laser mode numbers with anisotropic crystal as a gain medium.

  13. Generation regimes of bidirectional hybridly mode-locked ultrashort pulse erbium-doped all-fiber ring laser with a distributed polarizer.

    Science.gov (United States)

    Krylov, Alexander A; Chernykh, Dmitriy S; Arutyunyan, Natalia R; Grebenyukov, Vyacheslav V; Pozharov, Anatoly S; Obraztsova, Elena D

    2016-05-20

    We report on the stable picosecond and femtosecond pulse generation from the bidirectional erbium-doped all-fiber ring laser hybridly mode-locked with a coaction of a single-walled carbon nanotube-based saturable absorber and nonlinear polarization evolution that was introduced through the insertion of the short-segment polarizing fiber. Depending on the total intracavity dispersion value, the laser emits conservative solitons, transform-limited Gaussian pulses, or highly chirped stretched pulses with almost 20 nm wide parabolic spectrum in both clockwise (CW) and counterclockwise (CCW) directions of the ring. Owing to the polarizing action in the cavity, we have demonstrated for the first time, to the best of our knowledge, an efficient tuning of soliton pulse characteristics for both CW and CCW channels via an appropriate polarization control. We believe that the bidirectional laser presented may be highly promising for gyroscopic and other dual-channel applications.

  14. Aerosol optical depth and fine-mode fraction retrieval over East Asia using multi-angular total and polarized remote sensing

    Science.gov (United States)

    Cheng, T.; Gu, X.; Xie, D.; Li, Z.; Yu, T.; Chen, H.

    2012-03-01

    A new aerosol retrieval algorithm using multi-angular total and polarized measurements is presented. The algorithm retrieves aerosol optical depth (AOD), fine-mode fraction (FMF) for studying the impact of aerosol on climate change. The retrieval algorithm is based on a lookup table (LUT) method, which assumes that one fine and one coarse lognormal aerosol modes can be combined with proper weightings to represent the ambient aerosol properties. To reduce the ambiguity in retrieval algorithm, the key characteristics of aerosol model over East Asia are constrained using the cluster analysis technique based on the AERONET sun-photometer observation over East Asia, and the fine and coarse modes are not fixed but can vary. A mixing model of bare soil and green vegetation spectra and the Nadal and Breon model for the bidirectional polarized reflectance factor (BPDF) were used to simulate total and polarized surface reflectance of East Asia. By applying the present algorithm to POLDER measurements, three different aerosol cases of clear, polluted and dust are analyzed to test the algorithm. The comparison of retrieved aerosol optical depth (AOD) and fine-mode fraction (FMF) with those of AERONET sun-photometer observations show reliable results. Preliminary validation is encouraging. Using the new aerosol retrieval algorithm for multi-angular total and polarized measurements, the spatial and temporal variability of anthropogenic aerosol optical properties over East Asia, which were observed during a heavy polluted event, were analyzed. Exceptionally high values of aerosol optical depth contributed by fine mode of up to 0.5 (at 0.865 μm), and high values of fine-mode fraction of up to 0.9, were observed in this case study.

  15. Measurements of sub-degree B-mode polarization in the cosmic microwave background from 100 square degrees of SPTPOL data

    Energy Technology Data Exchange (ETDEWEB)

    Keisler, R.; Hoover, S.; Harrington, N.; Henning, J. W.; Ade, P. A. R.; Aird, K. A.; Austermann, J. E.; Beall, J. A.; Bender, A. N.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Chiang, H. C.; Cho, H-M.; Citron, R.; Crawford, T. M.; Crites, A. T.; de Haan, T.; Dobbs, M. A.; Everett, W.; Gallicchio, J.; Gao, J.; George, E. M.; Gilbert, A.; Halverson, N. W.; Hanson, D.; Hilton, G. C.; Holder, G. P.; Holzapfel, W. L.; Hou, Z.; Hrubes, J. D.; Huang, N.; Hubmayr, J.; Irwin, K. D.; Knox, L.; Lee, A. T.; Leitch, E. M.; Li, D.; Luong-Van, D.; Marrone, D. P.; McMahon, J. J.; Mehl, J.; Meyer, S. S.; Mocanu, L.; Natoli, T.; Nibarger, J. P.; Novosad, V.; Padin, S.; Pryke, C.; Reichardt, C. L.; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Schaffer, K. K.; Shirokoff, E.; Smecher, G.; Stark, A. A.; Story, K. T.; Tucker, C.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Yefremenko, V.; Zahn, O.

    2015-07-09

    We present a measurement of the B-mode polarization power spectrum (the BB spectrum) from 100 ${\\mathrm{deg}}^{2}$ of sky observed with SPTpol, a polarization-sensitive receiver currently installed on the South Pole Telescope. The observations used in this work were taken during 2012 and early 2013 and include data in spectral bands centered at 95 and 150 GHz. We report the BB spectrum in five bins in multipole space, spanning the range $300\\leqslant {\\ell }\\leqslant 2300$, and for three spectral combinations: 95 GHz × 95 GHz, 95 GHz × 150 GHz, and 150 GHz × 150 GHz. We subtract small (<0.5σ in units of statistical uncertainty) biases from these spectra and account for the uncertainty in those biases. The resulting power spectra are inconsistent with zero power but consistent with predictions for the BB spectrum arising from the gravitational lensing of E-mode polarization. If we assume no other source of BB power besides lensed B modes, we determine a preference for lensed B modes of 4.9σ. After marginalizing over tensor power and foregrounds, namely, polarized emission from galactic dust and extragalactic sources, this significance is 4.3σ. Fitting for a single parameter, ${A}_{\\mathrm{lens}}$, that multiplies the predicted lensed B-mode spectrum, and marginalizing over tensor power and foregrounds, we find ${A}_{\\mathrm{lens}}=1.08\\pm 0.26$, indicating that our measured spectra are consistent with the signal expected from gravitational lensing. The data presented here provide the best measurement to date of the B-mode power spectrum on these angular scales.

  16. Aerosol optical depth and fine-mode fraction retrieval over East Asia using multi-angular total and polarized remote sensing

    Directory of Open Access Journals (Sweden)

    T. Cheng

    2012-03-01

    Full Text Available A new aerosol retrieval algorithm using multi-angular total and polarized measurements is presented. The algorithm retrieves aerosol optical depth (AOD, fine-mode fraction (FMF for studying the impact of aerosol on climate change. The retrieval algorithm is based on a lookup table (LUT method, which assumes that one fine and one coarse lognormal aerosol modes can be combined with proper weightings to represent the ambient aerosol properties. To reduce the ambiguity in retrieval algorithm, the key characteristics of aerosol model over East Asia are constrained using the cluster analysis technique based on the AERONET sun-photometer observation over East Asia, and the fine and coarse modes are not fixed but can vary. A mixing model of bare soil and green vegetation spectra and the Nadal and Breon model for the bidirectional polarized reflectance factor (BPDF were used to simulate total and polarized surface reflectance of East Asia. By applying the present algorithm to POLDER measurements, three different aerosol cases of clear, polluted and dust are analyzed to test the algorithm. The comparison of retrieved aerosol optical depth (AOD and fine-mode fraction (FMF with those of AERONET sun-photometer observations show reliable results. Preliminary validation is encouraging. Using the new aerosol retrieval algorithm for multi-angular total and polarized measurements, the spatial and temporal variability of anthropogenic aerosol optical properties over East Asia, which were observed during a heavy polluted event, were analyzed. Exceptionally high values of aerosol optical depth contributed by fine mode of up to 0.5 (at 0.865 μm, and high values of fine-mode fraction of up to 0.9, were observed in this case study.

  17. Measurement of anchoring coefficient of homeotropically aligned nematic liquid crystal using a polarizing optical microscope in reflective mode

    Directory of Open Access Journals (Sweden)

    Sang-In Baek

    2015-09-01

    Full Text Available Although the homeotropic alignment of liquid crystals is widely used in LCD TVs, no easy method exists to measure its anchoring coefficient. In this study, we propose an easy and convenient measurement technique in which a polarizing optical microscope is used in the reflective mode with an objective lens having a low depth of focus. All measurements focus on the reflection of light near the interface between the liquid crystal and alignment layer. The change in the reflected light is measured by applying an electric field. We model the response of the director of the liquid crystal to the electric field and, thus, the change in reflectance. By adjusting the extrapolation length in the calculation, we match the experimental and calculated results and obtain the anchoring coefficient. In our experiment, the extrapolation lengths were 0.31 ± 0.04 μm, 0.32 ± 0.08 μm, and 0.23 ± 0.05 μm for lecithin, AL-64168, and SE-5662, respectively.

  18. High energy, 1572.3 nm pulses for CO2 LIDAR from a polarization-maintaining, very-large-mode-area, Er-doped fiber amplifier.

    Science.gov (United States)

    Nicholson, J W; DeSantolo, A; Yan, M F; Wisk, P; Mangan, B; Puc, G; Yu, A W; Stephen, M A

    2016-08-22

    We demonstrate the first polarization-maintaining, very-large-mode-area, Er-doped fiber amplifier with ~1100 μm2 effective area. The amplifier is core pumped by a Raman fiber laser and is used to generate single-frequency, one-microsecond, pulses with pulse energy of 541 μJ, peak power of 700 W, M2 of 1.1, and polarization extinction > 20 dB. The amplifier operates at 1572.3 nm, a wavelength useful for trace atmospheric CO2 detection.

  19. Assessment of the stereoselective fungal biotransformation of albendazole and its analysis by HPLC in polar organic mode.

    Science.gov (United States)

    Hilário, Viviane Cangerana; Carrão, Daniel Blascke; Barth, Thiago; Borges, Keyller Bastos; Furtado, Niege Araçari Jacometti Cardoso; Pupo, Mônica Tallarico; de Oliveira, Anderson Rodrigo Moraes

    2012-03-05

    A high-performance liquid chromatographic method using polar organic mode was developed to analyze albendazole (ABZ), albendazole sulfone (ABZSO(2)) and the chiral and active metabolite albendazole sulfoxide (ABZSOX, ricobendazole) that was further applied in stereoselective fungal biotransformation studies. The chromatographic separation was performed on a Chiralpak AS column using acetonitrile:ethanol (97:3, v/v) plus 0.2% triethylamine and 0.2% acetic acid as the mobile phase at a flow rate of 0.5 mL min(-1). The present study employed hollow fiber liquid-phase microextraction as sample preparation. The method showed to be linear over the concentration range of 25-5000 ng mL(-1) for each ABZSOX enantiomer, 200-10,000 ng mL(-1) for ABZ and 50-1000 ng mL(-1) for ABZSO(2) metabolite with correlation coefficient (r)>0.9934. The mean recoveries for ABZ, rac-ABZSOX and ABZSO(2) were, respectively, 9%, 33% and 20% with relative standard deviation below 10%. Within-day and between-day precision and accuracy assays for these analytes were studied at three concentration levels and were lower than 15%. This study opens the door regarding the possibility of using fungi in obtaining of the active metabolite ricobendazole. Nigrospora sphaerica (Sacc.) E. W. Mason (SS67), Pestalotiopsis foedans (VR8), Papulaspora immersa Hotson (SS13) and Mucor rouxii were able to stereoselectively metabolize ABZ into its chiral metabolite. Among them, the fungus Mucor rouxii was the most efficient in the production of (+)-ABZSOX.

  20. Mode-locking of a high power, 888 nm pumped Nd:YVO4 laser using nonlinear polarization rotation via Type I second harmonic generation.

    Science.gov (United States)

    Schäfer, Christoph; Fries, Christian; Theobald, Christian; L'huillier, Johannes A

    2013-01-15

    Continuous-wave mode-locking of a laser exploiting the nonlinear polarization rotation (NPR) technique via Type I second harmonic generation is demonstrated for the first time. The NPR is generated by a lithium triborate crystal and transformed into nonlinear cavity losses of a 888 nm pumped Nd:YVO4 laser. Self-starting, reliable mode-locking has been achieved at a high average output power of 20.6 W and a pulse duration of 7.3 ps. Furthermore, transform limited pulses down to 2.7 ps have been demonstrated at 9.9 W.

  1. Groove-type channel enhancement-mode AlGaN/GaN MIS HEMT with combined polar and nonpolar AlGaN/GaN heterostructures

    Science.gov (United States)

    Duan, Xiao-Ling; Zhang, Jin-Cheng; Xiao, Ming; Zhao, Yi; Ning, Jing; Hao, Yue

    2016-08-01

    A novel groove-type channel enhancement-mode AlGaN/GaN MIS high electron mobility transistor (GTCE-HEMT) with a combined polar and nonpolar AlGaN/GaN heterostucture is presented. The device simulation shows a threshold voltage of 1.24 V, peak transconductance of 182 mS/mm, and subthreshold slope of 85 mV/dec, which are obtained by adjusting the device parameters. Interestingly, it is possible to control the threshold voltage accurately without precisely controlling the etching depth in fabrication by adopting this structure. Besides, the breakdown voltage (V B) is significantly increased by 78% in comparison with the value of the conventional MIS-HEMT. Moreover, the fabrication process of the novel device is entirely compatible with that of the conventional depletion-mode (D-mode) polar AlGaN/GaN HEMT. It presents a promising way to realize the switch application and the E/D-mode logic circuits. Project supported by the National Science and Technology Major Project, China (Grant No. 2013ZX02308-002) and the National Natural Science Foundation of China (Grant Nos. 11435010, 61474086, and 61404099).

  2. Polar Interface Optical Phonon Modes and Froehlich Electron-Phonon Interaction Hamiltonians in an Arbitrary Layer-Number Quantum Well System

    Institute of Scientific and Technical Information of China (English)

    ZHANGLi; Hong-Jing; CHENChuan-Yu

    2003-01-01

    By using determinant method as in our recent work, the IO phonon modes, the orthogonal relation for polarization vector, electron-IO phonon F~6hlich interaction Hamiltonian, the dispersion relation, and the electron-phonon coupling function in an arbitrary layer-number quantum well system have been derived and investigated within the framework of dielectric continuum approximation. Numerical calculation on seven-layer AlxGal-xAs/GaAs systems have been performed. Via the numerical results in this work and previous works, the general characters of the IO phonon modes in an n-layer coupling quantum well system were concluded and summarized. This work can be regarded as a generalization of previous works on IO phonon modes in some fLxed layer-number quantum well systems, and it provides a uniform method to investittate the effects of IO phonons on the multi-layer coupling quantum well systems.

  3. Generation of isolated asymmetric umbilics in light's polarization

    CERN Document Server

    Galvez, Enrique J; Kumar, Vijay; Viswanathan, Nirmal K

    2014-01-01

    Polarization-singularity C-points, a form of line singularities, are the vectorial counterparts of the optical vortices of spatial modes and fundamental optical features of polarization-spatial modes. Their generation in tailored beams has been limited to lemon and star C-points that contain symmetric dislocations in state-of-polarization patterns. In this article we present the theory and laboratory measurements of two complementary methods to generate isolated asymmetric C-points in tailored beams, of which symmetric lemons and stars are limiting cases; and we report on the generation of monstars, an asymmetric C-point with characteristics of both lemons and stars.

  4. Study of different HILIC, mixed-mode, and other aqueous normal-phase approaches for the liquid chromatography/mass spectrometry-based determination of challenging polar pesticides.

    Science.gov (United States)

    Vass, Andrea; Robles-Molina, José; Pérez-Ortega, Patricia; Gilbert-López, Bienvenida; Dernovics, Mihaly; Molina-Díaz, Antonio; García-Reyes, Juan F

    2016-07-01

    The aim of the study was to evaluate the performance of different chromatographic approaches for the liquid chromatography/mass spectrometry (LC-MS(/MS)) determination of 24 highly polar pesticides. The studied compounds, which are in most cases unsuitable for conventional LC-MS(/MS) multiresidue methods were tested with nine different chromatographic conditions, including two different hydrophilic interaction liquid chromatography (HILIC) columns, two zwitterionic-type mixed-mode columns, three normal-phase columns operated in HILIC-mode (bare silica and two silica-based chemically bonded columns (cyano and amino)), and two standard reversed-phase C18 columns. Different sets of chromatographic parameters in positive (for 17 analytes) and negative ionization modes (for nine analytes) were examined. In order to compare the different approaches, a semi-quantitative classification was proposed, calculated as the percentage of an empirical performance value, which consisted of three main features: (i) capacity factor (k) to characterize analyte separation from the void, (ii) relative response factor, and (iii) peak shape based on analytes' peak width. While no single method was able to provide appropriate detection of all the 24 studied species in a single run, the best suited approach for the compounds ionized in positive mode was based on a UHPLC HILIC column with 1.8 μm particle size, providing appropriate results for 22 out of the 24 species tested. In contrast, the detection of glyphosate and aminomethylphosphonic acid could only be achieved with a zwitterionic-type mixed-mode column, which proved to be suitable only for the pesticides detected in negative ion mode. Finally, the selected approach (UHPLC HILIC) was found to be useful for the determination of multiple pesticides in oranges using HILIC-ESI-MS/MS, with limits of quantitation in the low microgram per kilogram in most cases. Graphical Abstract HILIC improves separation of multiclass polar pesticides.

  5. Completely monolithic linearly polarized high-power fiber laser oscillator

    Science.gov (United States)

    Belke, Steffen; Becker, Frank; Neumann, Benjamin; Ruppik, Stefan; Hefter, Ulrich

    2014-03-01

    We have demonstrated a linearly polarized cw all-in-fiber oscillator providing 1 kW of output power and a polarization extinction ratio (PER) of up to 21.7 dB. The design of the laser oscillator is simple and consists of an Ytterbium-doped polarization maintaining large mode area (PLMA) fiber and suitable fiber Bragg gratings (FBG) in matching PLMA fibers. The oscillator has nearly diffraction-limited beam quality (M² high power 6+1:1 pump coupler. The slope efficiency of the laser is 75 %. The electro/optical efficiency of the complete laser system is ~30 % and hence in the range of Rofin's cw non-polarized fiber lasers. Choosing an adequate bending diameter for the Yb-doped PLMA fiber, one polarization mode as well as higher order modes are sufficiently supressed1. Resulting in a compact and robust linearly polarized high power single mode laser without external polarizing components. Linearly polarized lasers are well established for one dimensional cutting or welding applications. Using beam shaping optics radially polarized laser light can be generated to be independent from the angle of incident to the processing surface. Furthermore, high power linearly polarized laser light is fundamental for nonlinear frequency conversion of nonlinear materials.

  6. Polarization insensitive and low-loss coupling mode-size converter from super luminescent diode to silica-based planar lightwave circuit

    Science.gov (United States)

    She, Xuan; Li, Bei; Chen, Kan; Li, Ke; Shu, Xiaowu; Liu, Cheng

    2017-02-01

    We present a design of a laterally tapered optical waveguide mode-size converter from super luminescent diode (SLD) to silica-based planar lightwave circuit (PLC). The mode-size converter is based on silica-based PLC. By using three dimensional semi-vectorial beam propagation methods, laterally tapered waveguides with different boundaries are simulated and compared with each other, where the factors of polarization-dependent loss and coupling loss are mainly focused on. The results show that the most influential factor for polarization-dependent loss is the ratio of the divergence angle of SLD in the horizontal direction and the vertical direction. The refractive index difference Δ between core layer and cladding layer, core width of endface and taper length influence coupling loss mostly, while the effect of all side boundaries is within 0.05 dB. We also investigate the SLD misalignment tolerance and wavelength bandwidth's impact on coupling loss. Furthermore, we examine the performance of the mode-size converter based on a particular SLD which has a divergence angle of 30°×45°. By optimizing the parameters of the tapered waveguide, the coupling efficiency is increased to 62.4% and the polarization-dependent loss is reduced to 0.035 dB. Meanwhile, it eΔnables us to reduce the coupling loss variation to 0.05dB with core width of endface fabrication tolerance of ±0.5 μm and taper length tolerance of ±0.5 mm. The proposed mode-size converter has been demonstrated to be well performed, implying its application in the optical transceiver module using SLD as light source and hybrid integration of III-V semiconductor waveguiding devices and PLCs.

  7. Electron binding energies and the fundamental gap of a push-pull dye in a polar environment: p-nitroaniline in liquid water

    Science.gov (United States)

    Cabral, Benedito J. C.

    2017-01-01

    The outer valence electron binding energies and the fundamental gap of p-nitroaniline (PNA) in water were determined by electron propagator theory. The adopted methodology relies on the calculation of electron binding energies by using configurations generated by Born-Oppenheimer molecular dynamics of PNA in water. The fundamental gap (Eg) of PNA in water was estimated from the first ionisation energy (IE) and the first vertical electron affinity VEA (Eg = IE-VEA). In liquid water Eg is predicted to be 6.5 ± 0.5 eV (OVGF), which is ∼3.3 eV greater than the experimental optical gap (3.25 eV).

  8. 基于WalkGIS的地形数据建库加工整理模式%The Processing Mode with Data Built into 1∶ 500 Fundamental Geographic Database on WalkGIS Basis

    Institute of Scientific and Technical Information of China (English)

    张玲; 李育平

    2012-01-01

    以1∶500基础地理信息数据加工整理模式为研究对象,对数据整理的技术要求和整理方法进行了清晰的阐述,总结出一套基于WalkGIS平台的基础地理信息数据库建库数据加工整理模式,为数据整理工作提供参考。%This paper studies on the processing mode with data built into 1:500 fundamental geographic database,elaborates the technical requirements and methods of data processing.The mode with data built into 1∶500 fundamental geographic database on WalkGIS basis has been put forward,and it offers a reference for data conformity.

  9. Single input state, single–mode fiber–based polarization sensitive optical frequency domain imaging by eigenpolarization referencing

    Science.gov (United States)

    Lippok, Norman; Villiger, Martin; Jun, Chang–Su; Bouma, Brett E.

    2015-01-01

    Fiber–based polarization sensitive OFDI is more challenging than free–space implementations. Using multiple input states, fiber–based systems provide sample birefringence information with the benefit of a flexible sample arm but come at the cost of increased system and acquisition complexity, and either reduce acquisition speed or require increased acquisition bandwidth. Here we show that with the calibration of a single polarization state, fiber–based configurations can approach the conceptual simplicity of traditional free–space configurations. We remotely control the polarization state of the light incident at the sample using the eigenpolarization states of a wave plate as a reference, and determine the Jones matrix of the output fiber. We demonstrate this method for polarization sensitive imaging of biological samples. PMID:25927775

  10. Observation of mode instability and coherence collapse in a single-frequency polarization-maintaining fiber ring laser

    Science.gov (United States)

    Ma, Mingxiang; Hu, Zhengliang; Xu, Pan; Hu, Yongming

    2014-06-01

    Mode instability acts as a common feature in single-frequency fiber ring lasers. The mechanism of coherence collapse by mode instability is theoretically analyzed and demonstrated with an unbalanced fiber Michelson interferometer utilizing phase modulation, which is illuminated by a single-frequency erbium-doped fiber ring laser. Multiform mode instability phenomena accompanied with coherence collapse are observed and discussed in detail by tracing the dynamics of the interference fringe visibility. The results show that mode instability would introduce extra phase noises like a false alarm to interferometric fiber optic sensing systems.

  11. Note: Leaf undulator to realize polarization control with low on-axis heat load.

    Science.gov (United States)

    Yan, J; Qiao, S

    2010-05-01

    Here, a new operational mode of an electromagnetic elliptical undulator, called leaf undulator, is proposed and studied. It can provide linearly polarized radiation at an arbitrary polarization direction depending on the magnitude and polarity of the horizontal and vertical magnetic fields. The polarization direction becomes 45 degrees when the horizontal and vertical magnetic fields are equal in strength. It is also able to switch the operational mode to purely circular or elliptical one. To lower the on-axis power density generated by undulators operating in linear mode, different designs have been presented in the past. Leaf undulator can suppress the on-axis power density by an order of magnitude compared to the so-called Knot and Figure-8 undulators, while maintaining comparable photon flux of the fundamental harmonic. Furthermore, it is possible to reach a lower fundamental energy under linear mode than by any other design using comparable magnetic field strengths.

  12. Investigation of the Stability of the Ruthenium based Dye (N719) Utilizing the Polarization Properties of Dispersive Raman Modes and/or of the Fluorescent Emission

    DEFF Research Database (Denmark)

    Hassing, Søren; Jernshøj, Kit Drescher; Phuong, Nguyen

    2013-01-01

    Dye-sensitized solar cells (DSCs) offer intriguing new possibilities with the integration of these into, e.g., power generating windows or facade applications. For the DSCs to constitute a viable investment, the thermal appliance with respect to the working conditions typically encountered must...... be considered. One of the aspects governing the long-term thermal stability of the DSC is the dye stability and hence whether or not the dye is degraded upon heating or illumination. This emphasizes the need for a sensitive and nondestructive measuring technique with which it is possible to distinguish between...... for short) is possible by exploiting a combination of the polarization properties of the dispersive Raman modes with the small spectral change in the visible absorption spectrum and/or the difference in the polarization of the fluorescence related to the difference in molecular configuration. By measuring...

  13. Separation of polar mushroom toxins by mixed-mode hydrophilic and ionic interaction liquid chromatography-electrospray ionization-mass spectrometry.

    Science.gov (United States)

    Chung, Wai-cheung; Tso, Sau-ching; Sze, Sai-tim

    2007-02-01

    Reversed-phase liquid chromatography (RPLC) is commonly used to analyze nonvolatile contaminants and naturally occurring toxins in foods. However, polar compounds, such as hydrophilic polypeptides and quaternary ammonium salts, are often not satisfactorily separated by RPLC and present a challenge for analytical scientists. In this study, hydrophilic interaction liquid chromatography (HILIC), on an amide-based stationary phase in combination with electrospray ionization (ESI) tandem mass spectrometry (MS-MS), is successfully employed to simultaneously separate polar mushroom toxins, including amanitins and phallotoxins, which are cyclic oligopeptides and muscarine, a quaternary ammonium compound, in mushrooms. The sensitivity of different ionization modes is studied, and the positive ionization mode is found to provide a more sensitive and effective tool for the unambiguous identification of the concerned polar toxins because of their characteristic fragmentation patterns. The properties of the mobile phase are also found to have significant impacts on the separation. At a high acetonitrile (ACN) concentration, hydrophilic interaction dominates, and all analytes under study demonstrate a much higher affinity with the stationary phase. The addition of methanol (MeOH) as a modifier could further enhance the HILIC separation for amanitins, phallotoxins, and muscarine. Valley-to-valley separation is achieved upon the optimatizatiqn of the mobile phase (comprising of ACN, MeOH, and ammonium formate buffer at pH approximately 3.5) and the solvent gradient. HILIC coupled with ESI-MS-MS is demonstrated to be a novel technique for the simultaneous separation and confirmatory analysis of the concerned polar toxins by providing an environment of solubility and retention that could not be achieved through the use of RPLC.

  14. Dynamic Multi-Party Quantum Private Comparison Protocol with Single Photons in Both Polarization and Spatial-Mode Degrees of Freedom

    Science.gov (United States)

    Liu, Wen; Wang, Yong-Bin

    2016-12-01

    A dynamic quantum private comparison protocol based on the single photons in both polarization and spatial-mode degrees of freedom is proposed. In this protocol, any two parties of n( n ≥ 4) parties can compare their private information with the help of others n - 2 parties. And any party can join in the protocol to take part in the comparison of n parties. Correctness analysis shows that the proposed protocol can be used to compare their information correctly. Security analysis shows that the proposed protocol can resist the general active attacks from an outside eavesdropper. And it can overcomes the problem of information leakage.

  15. Non-linearly phased 2-D array transducers arranged on a cylindrical-polar grid for real time guided wave mode control and steering

    Science.gov (United States)

    Kannajosyula, H.; Lissenden, C. J.; Rose, J. L.

    2012-05-01

    Ultrasonic guided wave mode control and steering using phased array transducers (PATs) is studied. A PAT with elements arranged on a cylindrical-polar grid is proposed to overcome the problem of large side-lodes associated with a rectangular grid PAT. The PAT is visualized as a spatio-temporal filter to calculate phase delays. Wavenumber bands resulting from the radial rows enable constructive interfere only in the vicinity of the desired wavenumber and angle of propagation. Finite element simulations are presented to study PAT performance.

  16. Mode-locked femtosecond all polarization-maintaining erbium-doped dispersion managed fiber laser based on a nonlinear amplifying loop mirror

    Science.gov (United States)

    Wu, Wenjue; Zhou, Yue; Sun, Ji; Dai, Yitang; Yin, Feifei; Dai, Jian; Xu, Kun

    2016-11-01

    We proposed a mode-locked all-polarization-maintaining erbium-doped fiber laser base on a nonlinear amplifying loop mirror (NALM). The laser can generate 1.6 ps pulses at 1550 nm with the energy of 1 nJ that can be compressed down to 100 fs with the compressor outside the cavity. The repetition rate of the output pulse is 12MHz. Such configuration of laser is easier controlled and self starting long term operation, and is highly desirable for industrial applications, such as micro-machining.

  17. Information Leakage in Efficient Bidirectional Quantum Secure Direct Communication with Single Photons in Both Polarization and Spatial-Mode Degrees of Freedom

    Science.gov (United States)

    Zhang, Cai; Situ, Haozhen

    2016-11-01

    Recently, Wang et al. presented a bidirectional quantum secure direct communication protocol with single photons in both polarization and spatial-mode degrees of freedom (Int. J. Theor. Phys. 54(10): 3443-3453, 2015). They claimed that their protocol was efficient and removed the drawback of information leakage. However, we found that the information leakage actually exists in their protocol. In this paper, we analyze Wang et al.'s protocol in detail. In addition, we propose an improvement to avoid the information leakage. The security of the improved protocol has also been discussed.

  18. Three-dimensional coupled-wave theory for the guided mode resonance in photonic crystal slabs: TM-like polarization.

    Science.gov (United States)

    Yang, Yi; Peng, Chao; Liang, Yong; Li, Zhengbin; Noda, Susumu

    2014-08-01

    A general coupled-wave theory is presented for the guided resonance in photonic crystal (PhC) slabs with TM-like polarization. Numerical results based on our model are presented with finite-difference time-domain validations. The proposed analysis facilitates comprehensive understanding of the physics of guided resonance in PhC slabs and provides guidance for its applications.

  19. Nonlinear force dependence on optically bound arrays of micro-particles trapped in the evanescent fields of fundamental and higher order microfibre modes

    CERN Document Server

    Maimaiti, Aili; Truong, Viet Giang; Ritsch, Helmut; Chormaic, Sile Nic

    2016-01-01

    Particles trapped in the evanescent field of an ultrathin optical fibre interact over very long distances via multiple scattering of the fibre-guided fields. In ultrathin fibres that support higher order modes these interactions are stronger and exhibit qualitatively new behaviour due to the coupling of different fibre modes, which have different propagation wave vectors, by the particles. Here, we study one dimensional longitudinal optical binding interactions of chains of 3 {\\mu}m polystyrene spheres under the influence of the evanescent fields of a two-mode microfibre. The observation of long-range interactions, self-ordering and speed variation of particle chains reveals strong optical binding effects between the particles, which can be well modelled by a tritter scattering-matrix approach. The optical forces, optical binding interactions and the velocity of bounded particle chains are calculated using this method. Results show good agreement with finite element numerical simulations. Experimental data an...

  20. Evidence of a circularly polarized light mode along the optic axis in c-cut NH{sub 4}H{sub 2}PO{sub 4}, induced by circular differential reflection and anomalous birefringence

    Energy Technology Data Exchange (ETDEWEB)

    Kaminsky, Werner; Steininger, Steven [Department of Chemistry, University of Washington, Seattle, WA 98195 (United States); Herreros-Cedres, Javier [Departmento de Fisica Basica, Facultad de Fisica, University De La Laguna, La Laguna, Tenerife (Spain); Glazer, Anthony Michael, E-mail: kaminsky@chem.washington.ed [Clarendon Laboratory, University of Oxford, Oxford (United Kingdom)

    2010-03-10

    The anomalous birefringence and circular differential reflection of NH{sub 4}H{sub 2}PO{sub 4} (4-bar2m), cut on the optic axis, have been found to cause an additional signal in measurements of the optical rotation employing polarized light technology, with the sample between crossed and slightly modulated linear polarizers (tilting high accuracy universal polarimetry). The azimuthal rotation of the linearly polarized light, up to 100 times larger than expected, is described in terms of a circularly polarized light mode along the optic axis of varying amplitude. Experimental evidence leading to our conclusion is given and a qualitative model for the effect is presented.

  1. Nonlinear force dependence on optically bound micro-particle arrays in the evanescent fields of fundamental and higher order microfibre modes.

    Science.gov (United States)

    Maimaiti, Aili; Holzmann, Daniela; Truong, Viet Giang; Ritsch, Helmut; Nic Chormaic, Síle

    2016-07-25

    Particles trapped in the evanescent field of an ultrathin optical fibre interact over very long distances via multiple scattering of the fibre-guided fields. In ultrathin fibres that support higher order modes, these interactions are stronger and exhibit qualitatively new behaviour due to the coupling of different fibre modes, which have different propagation wave-vectors, by the particles. Here, we study one dimensional longitudinal optical binding interactions of chains of 3 μm polystyrene spheres under the influence of the evanescent fields of a two-mode microfibre. The observation of long-range interactions, self-ordering and speed variation of particle chains reveals strong optical binding effects between the particles that can be modelled well by a tritter scattering-matrix approach. The optical forces, optical binding interactions and the velocity of bounded particle chains are calculated using this method. Results show good agreement with finite element numerical simulations. Experimental data and theoretical analysis show that higher order modes in a microfibre offer a promising method to not only obtain stable, multiple particle trapping or faster particle propulsion speeds, but that they also allow for better control over each individual trapped object in particle ensembles near the microfibre surface.

  2. Nonlinear force dependence on optically bound micro-particle arrays in the evanescent fields of fundamental and higher order microfibre modes

    Science.gov (United States)

    Maimaiti, Aili; Holzmann, Daniela; Truong, Viet Giang; Ritsch, Helmut; Nic Chormaic, Síle

    2016-01-01

    Particles trapped in the evanescent field of an ultrathin optical fibre interact over very long distances via multiple scattering of the fibre-guided fields. In ultrathin fibres that support higher order modes, these interactions are stronger and exhibit qualitatively new behaviour due to the coupling of different fibre modes, which have different propagation wave-vectors, by the particles. Here, we study one dimensional longitudinal optical binding interactions of chains of 3 μm polystyrene spheres under the influence of the evanescent fields of a two-mode microfibre. The observation of long-range interactions, self-ordering and speed variation of particle chains reveals strong optical binding effects between the particles that can be modelled well by a tritter scattering-matrix approach. The optical forces, optical binding interactions and the velocity of bounded particle chains are calculated using this method. Results show good agreement with finite element numerical simulations. Experimental data and theoretical analysis show that higher order modes in a microfibre offer a promising method to not only obtain stable, multiple particle trapping or faster particle propulsion speeds, but that they also allow for better control over each individual trapped object in particle ensembles near the microfibre surface. PMID:27451935

  3. Radiology fundamentals

    CERN Document Server

    Singh, Harjit

    2011-01-01

    ""Radiology Fundamentals"" is a concise introduction to the dynamic field of radiology for medical students, non-radiology house staff, physician assistants, nurse practitioners, radiology assistants, and other allied health professionals. The goal of the book is to provide readers with general examples and brief discussions of basic radiographic principles and to serve as a curriculum guide, supplementing a radiology education and providing a solid foundation for further learning. Introductory chapters provide readers with the fundamental scientific concepts underlying the medical use of imag

  4. Supercontinuum generation based on all-normal-dispersion Yb-doped fiber laser mode-locked by nonlinear polarization rotation: Influence of seed's output port

    Science.gov (United States)

    Xiao, Xiaosheng; Hua, Yi

    2016-10-01

    All-normal-dispersion (ANDi) mode-locked Yb-doped fiber laser is a promising seed source for supercontinuum (SC) generation, due to its compact structure and broadband output. The influences of output ports of the ANDi laser mode-locked by nonlinear polarization rotation (NPR), on the generated SC are investigated. Two output ports of ANDi laser are considered, one of which is the conventional nonlinear polarization rotation (NPR) port and the other is extracted from a coupler after the NPR port. It is found that, the SC originated from the coupler port is much broader than that from the NPR port, which is validated by lots of experiments with different output parameters. Furthermore, the conclusion is verified and generalized to general ANDi lasers by numerical simulations, because the output pulse from coupler port could be cleaner than that from NPR port. Besides, there are no significant differences in the phase coherence and temporal stability between the SCs generated from both ports. Hence for the SC generation based on ANDi laser, it is preferred to use the pulse of coupler port (i.e. pulse after NPR port) serving as the seed source.

  5. Stable single-polarization single-longitudinal-mode linear cavity erbium-doped fiber laser based on structured chirped fiber Bragg grating.

    Science.gov (United States)

    Yin, Bin; Liu, Zhibo; Feng, Suchun; Bai, Yunlong; Li, Haisu; Jian, Shuisheng

    2015-01-01

    A novel linear cavity erbium-doped fiber (EDF) laser based on a structured chirped fiber Bragg grating (CFBG) filter is proposed for stable single-polarization (SP) single-longitudinal-mode (SLM) operation. For the first time, to the best of our knowledge, a structured CFBG filter with an ultranarrow transmission band which is generated by tapering directly on CFBG is used to select the laser longitudinal mode. The SLM operation is obtained by using the structured CFBG together with an unpumped EDF acting as a saturable absorber. The fluctuations of the laser peak power and center wavelength are less than 0.07 dB and 1 pm in 1 h, respectively. The stable SP operation is achieved by using the inline broadband polarizer. The measured 20 dB laser linewidth is about 27.7 kHz, which indicates the laser linewidth is approximately 1.39 kHz FWHM.

  6. Fundamental Limits of Ultrathin Metasurfaces

    CERN Document Server

    Arbabi, Amir

    2014-01-01

    We present universal theoretical limits on the operation and performance of non-magnetic passive ultrathin metasurfaces. In particular, we prove that their local transmission, reflection, and polarization conversion coefficients are confined to limited regions of the complex plane. As a result, full control over the phase of the light transmitted through such metasurfaces cannot be achieved if the polarization of the light is not to be affected at the same time. We also establish fundamental limits on the maximum polarization conversion efficiency of these metasurfaces, and show that they cannot achieve more than 25% polarization conversion efficiency in transmission.

  7. Switchable dual-mode all-fiber laser with few-mode fiber Bragg grating

    Science.gov (United States)

    Jin, Wenxing; Qi, Yanhui; Yang, Yuguang; Jiang, Youchao; Wu, Yue; Xu, Yao; Yao, Shuzhi; Jian, Shuisheng

    2017-09-01

    We propose a new approach to realize switchable mode operation in a few-mode erbium-doped fiber laser. The ring fiber laser structure is constructed with a core-offset splicing between single-mode fiber and dual-mode fiber. Stable operating on the fundamental mode laser and second-order mode laser individually or simultaneously is realized by appropriately adjusting the state of the polarization controller and bending status of the few-mode fiber Bragg grating. The narrow 3 dB linewidth less than 0.02 nm and high optical signal to noise ratio more than 42 dB are obtained for both modes in either separate laser or simultaneous laser operating conditions.

  8. Planck intermediate results. L. Evidence for spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB $B$-mode analysis

    CERN Document Server

    Aghanim, N; Aumont, J; Baccigalupi, C; Ballardini, M; Banday, A J; Barreiro, R B; Bartolo, N; Basak, S; Benabed, K; Bernard, J -P; Bersanelli, M; Bielewicz, P; Bonaldi, A; Bonavera, L; Bond, J R; Borrill, J; Bouchet, F R; Boulanger, F; Bracco, A; Burigana, C; Calabrese, E; Cardoso, J -F; Chiang, H C; Colombo, L P L; Combet, C; Comis, B; Crill, B P; Curto, A; Cuttaia, F; Davis, R J; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J -M; Di Valentino, E; Dickinson, C; Diego, J M; Doré, O; Douspis, M; Ducout, A; Dupac, X; Dusini, S; Efstathiou, G; Elsner, F; Enßlin, T A; Eriksen, H K; Falgarone, E; Fantaye, Y; Finelli, F; Frailis, M; Fraisse, A A; Franceschi, E; Frolov, A; Galeotta, S; Galli, S; Ganga, K; Génova-Santos, R T; Gerbino, M; Ghosh, T; Giard, M; González-Nuevo, J; Górski, K M; Gregorio, A; Gruppuso, A; Gudmundsson, J E; Hansen, F K; Helou, G; Herranz, D; Hivon, E; Huang, Z; Jaffe, A H; Jones, W C; Keihänen, E; Keskitalo, R; Kisner, T S; Krachmalnicoff, N; Kunz, M; Kurki-Suonio, H; Lagache, G; Lähteenmäki, A; Lamarre, J -M; Lasenby, A; Lattanzi, M; Lawrence, C R; Jeune, M Le; Levrier, F; Liguori, M; Lilje, P B; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; Maggio, G; Maino, D; Mandolesi, N; Mangilli, A; Maris, M; Martin, P G; Martínez-González, E; Matarrese, S; Mauri, N; McEwen, J D; Melchiorri, A; Mennella, A; Migliaccio, M; Mitra, S; Miville-Deschênes, M -A; Molinari, D; Moneti, A; Montier, L; Morgante, G; Moss, A; Naselsky, P; Nørgaard-Nielsen, H U; Oxborrow, C A; Pagano, L; Paoletti, D; Partridge, B; Patrizii, L; Perdereau, O; Perotto, L; Pettorino, V; Piacentini, F; Plaszczynski, S; Polenta, G; Puget, J -L; Rachen, J P; Reinecke, M; Remazeilles, M; Renzi, A; Rocha, G; Rossetti, M; Roudier, G; Rubiño-Martín, J A; Ruiz-Granados, B; Salvati, L; Sandri, M; Savelainen, M; Scott, D; Sirignano, C; Sirri, G; Stanco, L; Suur-Uski, A -S; Tauber, J A; Tenti, M; Toffolatti, L; Tomasi, M; Tristram, M; Trombetti, T; Valiviita, J; Vansyngel, J; Van Tent, F; Vielva, P; Wandelt, B D; Wehus, I K; Zacchei, A; Zonca, A

    2016-01-01

    The characterization of the Galactic foregrounds has been shown to be the main obstacle in the challenging quest to detect primordial B-modes in the polarized microwave sky. We make use of the Planck-HFI 2015 data release at high frequencies to place new constraints on the properties of the polarized thermal dust emission at high Galactic latitudes. Here, we specifically study the spatial variability of the dust polarized spectral energy distribution, and its potential impact on the determination of the tensor-to-scalar ratio. We use the correlation ratio of the $C_\\ell^{BB}$ angular power spectra between the 217- and 353-GHz channels as a tracer of these potential variations, computed on different high Galactic latitude regions, ranging from 80% to 20% of the sky. The new insight from Planck data is a departure of the correlation ratio from unity that cannot be attributed to a spurious decorrelation due to the cosmic microwave background, instrumental noise, or instrumental systematics. The effect is margina...

  9. Nonlinear ion modes in a strongly coupled plasma in the presence of nonthermal ion fluids and polarization force

    Science.gov (United States)

    Ema, S. A.; Hossen, M. R.; Mamun, A. A.

    2016-04-01

    The nonlinear propagation of ion-acoustic (IA) waves in a strongly coupled plasma system containing Maxwellian electrons and nonthermal ions has been theoretically and numerically investigated. The well-known reductive perturbation technique is used to derive both the Burgers and Korteweg-de Vries (KdV) equations. Their shock and solitary wave solutions have also been numerically analyzed in understanding localized electrostatic disturbances. It has been observed that the basic features (viz. polarity, amplitude, width, etc.) of IA waves are significantly modified by the effect of polarization force and other plasma parameters (e.g., the electron-to-ion number density ratio and ion-to-electron temperature ratio). This is a unique finding among all theoretical investigations made before, whose probable implications are discussed in this investigation. The implications of the results obtained from this investigation may be useful in understanding the wave propagation in both space and laboratory plasmas.

  10. Wyckoff positions and the expression of polarization singularities in photonic crystals.

    Science.gov (United States)

    Wheeldon, Jeffrey F; Schriemer, Henry

    2009-02-16

    We reveal the fundamental relation between linear photonic crystal symmetries and the local polarization states of its Bloch modes, in particular the location and nature of polarization singularities as established by rigorous group theoretic analysis, encompassing the full system symmetry. This is illustrated with the fundamental transverse electric mode of a two-dimensional hexagonal photonic crystal, in the vanishing contrast limit and at the K point. For general Wyckoff positions within the fundamental domain, the transformation of a local polarization state is determined by the nature of the symmetry operations that map to members of its crystallographic orbit. In particular, the site symmetries that correspond to specific Wyckoff positions constrain the local polarization state to singular character--circular, linear or disclination. Moreover, through the application of a local symmetry transformation relation, and the group's character table, the precise natures of the singularities may be determined from self-consistency arguments.

  11. Single all-optical platform for measurement of twist and transverse stress using polarization modulation in distinct dual-mode fiber placed in a Sagnac loop.

    Science.gov (United States)

    Khan, Saba N; Chatterjee, Sudip K; Chaudhuri, Partha Roy

    2016-01-01

    We report here the experimental demonstration of measurement of both twist and transverse stress using polarization modulation in a single all-fiber circuit consisting of a single-mode fiber (SMF)/dual-mode fiber (DMF) in a Sagnac interferometer (SI) loop. The SMF-SI prototype setup is seen to be suitable for precise measurement of twist over a broad range of ±50° and transverse stress up to 5 N with a sensitivity as high as 2.85×10(6)  pW/° and 2.08×10(7)  pW/N, respectively. It is envisaged that nearly ideal operation for twist measurement can be achieved by appropriately selecting the operating domain (pretwisted Sagnac loop for practical realization of the device) and required magnitude of applied transverse stress (weight yielding maximum sensitivity). Unlike SMF-SI, a DMF assisted SI exhibits asymmetric transmittance yielding a peak shift (∼45°) in addition to falling/rising peak amplitude of effective power(∼20  μW). This key characteristic is further utilized for tunable measurement of torsion (unidirectional from -70° to 40°) while keeping the sensitivity fixed. This research problem is then analyzed on the avenue of theoretical consideration and using classical polarization optics; we have derived the Jones birefringence matrix that accurately describes the transmission behavior of the configured fiber circuit (SMF-SI and DMF-SI) for each of the three cases, namely, transverse stress, twist, and both twist and transverse stress. Series of experimental measurements for various conditions of induced birefringence (linear/circular) were performed at length, and the results were compared with those determined theoretically towards configuring a twist and stress measuring device. The study provides an understanding of the underlying physics of dual-mode interference in a Sagnac configuration experiencing linear and circular birefringence.

  12. A theoretical investigation on the parametric instability excited by X-mode polarized electromagnetic wave at Tromsø

    Science.gov (United States)

    Wang, Xiang; Cannon, Patrick; Zhou, Chen; Honary, Farideh; Ni, Binbin; Zhao, Zhengyu

    2016-04-01

    Recent ionospheric modification experiments performed at Tromsø, Norway, have indicated that X-mode pump wave is capable of stimulating high-frequency enhanced plasma lines, which manifests the excitation of parametric instability. This paper investigates theoretically how the observation can be explained by the excitation of parametric instability driven by X-mode pump wave. The threshold of the parametric instability has been calculated for several recent experimental observations at Tromsø, illustrating that our derived equations for the excitation of parametric instability for X-mode heating can explain the experimental observations. According to our theoretical calculation, a minimum fraction of pump wave electric field needs to be directed along the geomagnetic field direction in order for the parametric instability threshold to be met. A full-wave finite difference time domain simulation has been performed to demonstrate that a small parallel component of pump wave electric field can be achieved during X-mode heating in the presence of inhomogeneous plasma.

  13. Surface-mode model of the extraordinary optical transmission without plasmons.

    Science.gov (United States)

    Xie, Yunya; Liu, Haitao; Jia, Hongwei; Zhong, Ying

    2015-03-09

    We propose a microscopic surface-mode model for the extraordinary optical transmission (EOT) through subwavelength metallic slit array covered with a thin dielectric layer under illumination of transverse-electric (TE) polarization. Remarkably, surface plasmon polarizations (SPPs) do not exist for this polarization. It is commonly believed that the waveguide mode in the dielectric layer plays a role similar to that of the SPP in classical EOT. To check the intuitive belief, we derive a surface-mode model by considering the multiple scattering process of the fundamental waveguide mode and neglecting all other residual field in the thin dielectric layer. The model captures the main feature of EOT and provides a phase-matching condition to predict the transmission resonance. Quantitative comparison between fully-vectorial calculations and model predictions shows that besides the fundamental waveguide mode, other residual field in the thin dielectric layer also contributes to the EOT without SPP.

  14. 保偏光纤模式耦合分析及其相干检测%Analysis and coherent detection of mode coupling of polarization maintaining fiber

    Institute of Scientific and Technical Information of China (English)

    郭振武; 温国强; 张红霞; 陈信伟; 刘铁根

    2012-01-01

    When there are structure imperfections within polarization maintaining fiber(PMF) and external perturbations acting on PMF, the polarization mode light which is propagating in PMF would be partly coupled into the other orthogonal one. The principle of the polarization mode coupling in PMF was analyzed. The detecting method of the mode coupling based on white-light interferometry was presented. Michelson interferometer was used to measure the spatial distribution and coupling intensity of polarization coupling along PMF. The optical path difference (OPD) between two arms of Michelson interferometer, changed by the movement of scanning arm reflector driven by a step motor, compensated the OPD of two orthogonal beams resulted from polarization coupling to realize the measurement of polarization coupling. In order to improve the sensitivity of the detection system, the signal-to-noise ratio of the output signal should be higher. By adding high-frequency modulation to the light emitted from the optical source and coherent demodulation to the signal detected by the photodiode, the disturbance and noise were restrained strongly. As a result, the peak SNR improved about 5.1 dB. The minimum coupling intensity of the system increased from -57.6 dB to -62.7 dB. The result shows that the ability to detect weaker coupling intensity of the system is enhanced.%当保偏光纤存在结构不均匀或者受到外部扰动时,将使其内部传输的一部分偏振光耦合到与其正交的偏振态上去.分析了保偏光纤内偏振光模式耦合的原理,给出了基于白光干涉法的偏振模式耦合检测方法,并用迈克尔逊干涉仪对保偏光纤的偏振模式耦合的耦合强度和耦合点发生的空间位置进行了测试.通过步进电机控制迈克尔逊干涉仪扫描臂的反射镜移动,改变干涉仪两臂之间的光程差,来补偿由于偏振耦合而形成的两偏振光从保偏光纤出射时的光程差,实现了对偏振耦合的测量.为

  15. Fundamental Astronomy

    CERN Document Server

    Karttunen, Hannu; Oja, Heikki; Poutanen, Markku; Donner, Karl Johan

    2007-01-01

    Fundamental Astronomy gives a well-balanced and comprehensive introduction to the topics of classical and modern astronomy. While emphasizing both the astronomical concepts and the underlying physical principles, the text provides a sound basis for more profound studies in the astronomical sciences. The fifth edition of this successful undergraduate textbook has been extensively modernized and extended in the parts dealing with the Milky Way, extragalactic astronomy and cosmology as well as with extrasolar planets and the solar system (as a consequence of recent results from satellite missions and the new definition by the International Astronomical Union of planets, dwarf planets and small solar-system bodies). Furthermore a new chapter on astrobiology has been added. Long considered a standard text for physical science majors, Fundamental Astronomy is also an excellent reference and entrée for dedicated amateur astronomers.

  16. BICEP2 / Keck Array VIII: Measurement of gravitational lensing from large-scale B-mode polarization

    CERN Document Server

    Array, The Keck; Ade, P A R; Ahmed, Z; Aikin, R W; Alexander, K D; Barkats, D; Benton, S J; Bischoff, C A; Bock, J J; Bowens-Rubin, R; Brevik, J A; Buder, I; Bullock, E; Buza, V; Connors, J; Crill, B P; Duband, L; Dvorkin, C; Filippin, J P; Fliescher, S; Grayson, J; Halpern, M; Harrison, S; Hildebrandt, S R; Hilton, G C; Hui, H; Irwin, K D; Kang, J; Karkare, K S; Karpel, E; Kaufman, J P; Keating, B G; Kefeli, S; Kernasovskiy, S A; Kovac, J M; Kuo, C L; Leitch, E M; Lueker, M; Megerian, K G; Namikawa, T; Netterfield, C B; Nguyen, H T; O'Brient, R; Ogburn, R W; Orlando, A; Pryke, C; Richter, S; Schwarz, R; Sheehy, C D; Staniszewski, Z K; Steinbach, B; Sudiwala, R V; Teply, G P; Thompson, K L; Tolan, J E; Tucker, C; Turner, A D; Vieregg, A G; Weber, A C; Wiebe, D V; Willmert, J; Wong, C L; Wu, W L K; Yoon, K W

    2016-01-01

    We present measurements of polarization lensing using the 150 GHz maps which include all data taken by the BICEP2 & Keck Array CMB polarization experiments up to and including the 2014 observing season (BK14). Despite their modest angular resolution ($\\sim 0.5^\\circ$), the excellent sensitivity ($\\sim 3\\mu$K-arcmin) of these maps makes it possible to directly reconstruct the lensing potential using only information at larger angular scales ($\\ell\\leq 700$). From the auto-spectrum of the reconstructed potential we measure an amplitude of the spectrum to be $A^{\\phi\\phi}_{\\rm L}=1.15\\pm 0.36$ (Planck $\\Lambda$CDM prediction corresponds to $A^{\\phi\\phi}_{\\rm L}=1$), and reject the no-lensing hypothesis at 5.8$\\sigma$, which is the highest significance achieved to date using EB lensing estimator. Taking the cross-spectrum of the reconstructed potential with the Planck 2015 lensing map yields $A^{\\phi\\phi}_{\\rm L}=1.13\\pm 0.20$. These direct measurements of $A^{\\phi\\phi}_L$ are consistent with the $\\Lambda$CDM...

  17. Systematically Asymmetric Heliospheric Magnetic Field: Evidence for a Quadrupole Mode and Non-Axisymmetry with Polarity Flip-Flops

    Science.gov (United States)

    Mursula, K.; Hiltula, T.

    2004-10-01

    Recent studies of the heliospheric magnetic field (HMF) have detected interesting, systematic hemispherical and longitudinal asymmetries which have a profound significance for the understanding of solar magnetic fields. The in situ HMF measurements since the 1960s show that the heliospheric current sheet (HCS) is systematically shifted (coned) southward during solar minimum times, leading to the concept of a bashful ballerina. While temporary shifts can be considerably larger, the average HCS shift (coning) angle is a few degrees, less than the 7.2∘ tilt of the solar rotation axis. Recent solar observations during the last two solar cycles verify these results and show that the magnetic areas in the northern solar hemisphere are larger and their intensity weaker than in the south during long intervals in the late declining to minimum phase. The multipole expansion reveals a strong quadrupole term which is oppositely directed to the dipole term. These results imply that the Sun has a symmetric quadrupole S0 dynamo mode that oscillates in phase with the dominant dipole A0 mode. Moreover, the heliospheric magnetic field has a strong tendency to produce solar tilts that are roughly opposite in longitudinal phase. This implies is a systematic longitudinal asymmetry and leads to a “flip-flop” type behaviour in the dominant HMF sector whose period is about 3.2 years. This agrees very well with the similar flip-flop period found recently in sunspots, as well as with the observed ratio of three between the activity cycle period and the flip-flop period of sun-like stars. Accordingly, these results require that the solar dynamo includes three modes, A0, S0 and a non-axisymmetric mode. Obviously, these results have a great impact on solar modelling.

  18. Modelization, fabrication and evaluation avalanche photodiodes polarized in Geiger mode for the single photon in astrophysics applications; Modelisation, fabrication et evaluation des photodiodes a avalanche polarisees en mode Geiger pour la detection du photon unique dans les applications Astrophysiques

    Energy Technology Data Exchange (ETDEWEB)

    Pellion, D

    2008-12-15

    The genesis of the work presented in this this is in the field of very high energy astrophysics. One century ago, scientists identified a new type of messenger coming from space: cosmic rays. This radiation consists of particles (photons or other) of very high energy which bombard the Earth permanently. The passage of cosmic radiations in the Earth's atmosphere results in the creation of briefs luminous flashes (5 ns) of very low intensity (1 pW), a Cherenkov flash, and then becomes visible on the ground. In the current state of the art the best detector of light today is the Photomultiplier tube (PMT), thanks to its characteristics of sensitivity and speed. But there are some drawbacks: low quantum efficiency, cost, weight etc. We present in this thesis a new alternative technology: silicon photon counters, made of photodiodes polarized in Geiger mode. This operating mode makes it possible to obtain an effect of multiplication comparable to that of the PMT. A physical and electrical model was developed to reproduce the behaviour of this detector. We then present in this thesis work an original technological process allowing the realization of these devices in the Center of Technology of LAAS-CNRS, with the simulation of each operation of the process. We developed a scheme for the electric characterization of the device, from the static mode to the dynamic mode, in order to check conformity with SILVACO simulations and to the initial model. Results are already excellent, given this is only a first prototype step, and comparable with the results published in the literature. These silicon devices can intervene in all the applications where there is a photomultiplier and replace it. The applications are thus very numerous and the growth of the market of these detectors is very fast. We present a first astrophysical experiment installed at the 'Pic du Midi' site which has detected Cherenkov flashes from cosmic rays with this new semiconductor technology

  19. Polarity at Many Levels

    Science.gov (United States)

    Flannery, Maura C.

    2004-01-01

    An attempt is made to find how polarity arises and is maintained, which is a central issue in development. It is a fundamental attribute of living things and cellular polarity is also important in the development of multicellular organisms and controversial new work indicates that polarization in mammals may occur much earlier than previously…

  20. Marketing fundamentals.

    Science.gov (United States)

    Redmond, W H

    2001-01-01

    This chapter outlines current marketing practice from a managerial perspective. The role of marketing within an organization is discussed in relation to efficiency and adaptation to changing environments. Fundamental terms and concepts are presented in an applied context. The implementation of marketing plans is organized around the four P's of marketing: product (or service), promotion (including advertising), place of delivery, and pricing. These are the tools with which marketers seek to better serve their clients and form the basis for competing with other organizations. Basic concepts of strategic relationship management are outlined. Lastly, alternate viewpoints on the role of advertising in healthcare markets are examined.

  1. LC-MS/MS determination of cinacalcet enantiomers in rat plasma on Chirobiotic V column in polar ionic mode: application to a pharmacokinetic study.

    Science.gov (United States)

    Ramisetti, Nageswara Rao; Bompelli, Sravan

    2014-12-01

    A simple and selective polar ionic liquid chromatography-tandem mass spectrometric method for separation and determination of cinacalcet enantiomers in rat plasma was developed and validated. The chromatographic separation was accomplished on a Chirobiotic V column packed with vancomycin as a chiral stationary phase using 2.5 mm ammonium formate in 100% methanol as a mobile phase in an isocratic mode of elution at a flow rate of 1.0 mL/min. The analytes were extracted from rat plasma by precipitating the proteins with acetonitrile. The developed method exhibited a linear dynamic range over 0.5-500 ng/mL in rat plasma for both enantiomers. The method was successfully applied to study the pharmacokinetics after a single dose by oral administration of 10 mg/kg of cinacalcet enantiomers to healthy male Wistar rats.

  2. 基于偏振模式转换的声光陀螺研究%Research of Acousto-Optical Gyroscope Based on Polarization-Mode Conversion

    Institute of Scientific and Technical Information of China (English)

    路书祥; 陈淑芬; 付雷; 邹正锋; 孟彦彬

    2012-01-01

    A type of acousto-optic gyroscope based on polarization-mode conversion is presented, the principle and structure is analyzed and some tests of the gyroscope are carried out. The sensitivity of sensor is also given. The statical result shows that the coupling efficient is 80.02% when the length of acousto-optic interaction is 15 mm, the input electrical power of surface acoustic wave (SAW) is 100 mW and the frequency of SAW is 168. 201 MHz. A linear voltage-rotation response curve of the gyroscope is obtained when rotating, and the sensitivity is 1 mV/[C)/s]. Acousto-optic gyroscope based on polarization-mode conversion keeps the advantage of SAW gyroscope, and the sensitivity is enhanced greatly.%提出一种基于偏振模式转换的声光陀螺,分析其原理与结构并对该陀螺进行实验测试.静态测试结果表明,当声光作用长度为15 mm,声表面波输入功率为100 mW,频率为168.201 MHz时,偏振模式转化效率为80.02%.在偏置条件下进行旋转测试,得到输出电压随陀螺转速呈线性变化的曲线,其灵敏度约为1 mY/[(°)/s].偏振型声光陀螺保留声表面波陀螺体积小、成本低等优点,而在灵敏度上有大幅提高.

  3. Fast and sensitive method to determine parabens by capillary electrophoresis using automatic reverse electrode polarity stacking mode: application to hair samples.

    Science.gov (United States)

    Sako, Alysson V F; Dolzan, Maressa D; Micke, Gustavo Amadeu

    2015-09-01

    This paper describes a fast and sensitive method for the determination of methyl, ethyl, propyl, and butylparaben in hair samples by capillary electrophoresis using automatic reverse electrode polarity stacking mode. In the proposed method, solutions are injected using the flush command of the analysis software (940 mbar) and the polarity switching is carried out automatically immediately after the sample injection. The advantages compared with conventional stacking methods are the increased analytical frequency, repeatability, and inter-day precision. All analyses were performed in a fused silica capillary (50 cm, 41.5 cm in effective length, 50 μm i.d.), and the background electrolyte was composed of 20 mmol L(-1) sodium tetraborate in 10 % of methanol, pH 9.3. For the reverse polarity, -25 kV/35 s was applied followed by application of +30 kV for the electrophoretic run. Temperature was set at 20 °C, and all analytes were monitored at 297 nm. The method showed acceptable linearity (r (2) > 0.997) in the studied range of 0.1-5.0 mg L(-1), limits of detection below 0.017 mg L(-1), and inter-day, intra-day, and instrumental precision better than 6.2, 3.6, and 4.6 %, respectively. Considering parabens is widely used as a preservative in many products and the reported possibility of damage to the hair and also to human health caused by these compounds, the proposed method was applied to evaluate the adsorption of parabens in hair samples. The results indicate that there is a greater adsorption of methylparaben compared to the other parabens tested and also dyed hairs had a greater adsorption capacity for parabens than natural hairs.

  4. LiteBIRD: a small satellite for the study of B-mode polarization and inflation from cosmic background radiation detection

    Science.gov (United States)

    Hazumi, M.; Borrill, J.; Chinone, Y.; Dobbs, M. A.; Fuke, H.; Ghribi, A.; Hasegawa, M.; Hattori, K.; Hattori, M.; Holzapfel, W. L.; Inoue, Y.; Ishidoshiro, K.; Ishino, H.; Karatsu, K.; Katayama, N.; Kawano, I.; Kibayashi, A.; Kibe, Y.; Kimura, N.; Koga, K.; Komatsu, E.; Lee, A. T.; Matsuhara, H.; Matsumura, T.; Mima, S.; Mitsuda, K.; Morii, H.; Murayama, S.; Nagai, M.; Nagata, R.; Nakamura, S.; Natsume, K.; Nishino, H.; Noda, A.; Noguchi, T.; Ohta, I.; Otani, C.; Richards, P. L.; Sakai, S.; Sato, N.; Sato, Y.; Sekimoto, Y.; Shimizu, A.; Shinozaki, K.; Sugita, H.; Suzuki, A.; Suzuki, T.; Tajima, O.; Takada, S.; Takagi, Y.; Takei, Y.; Tomaru, T.; Uzawa, Y.; Watanabe, H.; Yamasaki, N.; Yoshida, M.; Yoshida, T.; Yotsumoto, K.

    2012-09-01

    LiteBIRD [Lite (Light) satellite for the studies of B-mode polarization and Inflation from cosmic background Radiation Detection] is a small satellite to map the polarization of the cosmic microwave background (CMB) radiation over the full sky at large angular scales with unprecedented precision. Cosmological inflation, which is the leading hypothesis to resolve the problems in the Big Bang theory, predicts that primordial gravitational waves were created during the inflationary era. Measurements of polarization of the CMB radiation are known as the best probe to detect the primordial gravitational waves. The LiteBIRD working group is authorized by the Japanese Steering Committee for Space Science (SCSS) and is supported by JAXA. It has more than 50 members from Japan, USA and Canada. The scientific objective of LiteBIRD is to test all the representative inflation models that satisfy single-field slow-roll conditions and lie in the large-field regime. To this end, the requirement on the precision of the tensor-to-scalar ratio, r, at LiteBIRD is equal to or less than 0.001. Our baseline design adopts an array of multi-chroic superconducting polarimeters that are read out with high multiplexing factors in the frequency domain for a compact focal plane. The required sensitivity of 1.8μKarcmin is achieved with 2000 TES bolometers at 100mK. The cryogenic system is based on the Stirling/JT technology developed for SPICA, and the continuous ADR system shares the design with future X-ray satellites.

  5. Applying the data fusion method to evaluation of the performance of two control signals in monitoring polarization mode dispersion effects in fiber optic links

    Science.gov (United States)

    Dashtbani Moghari, M.; Rezaei, P.; Habibalahi, A.

    2015-02-01

    With increasing distance and bit rate in fiber optic links the effects of polarization mode dispersion (PMD) have been highlighted. Since PMD has a statistical nature, using a control signal that can provide accurate information to dynamically tune a PMD compensator is of great importance. In this paper, we apply the data fusion method with the aim of introducing a method that can be used to evaluate more accurately the performance of control signals before applying them in a PMD compensation system. Firstly, the minimum and average degree of polarization (DOP_min and DOP_ave respectively) as control signals in monitoring differential group delay (DGD) for a system including all-order PMD are calculated. Then, features including the amounts of sensitivity and ambiguity in DGD monitoring are calculated for NRZ data format as DGD to bit time (DGD/T) varies. It is shown that each of the control signals mentioned has both positive and negative features for efficient DGD monitoring. Therefore, in order to evaluate features concurrently and increase reliability, we employ data fusion to fuse features of each control signal, which makes evaluating and predicting the performance of control signals possible, before applying them in a real PMD compensation system. Finally, the reliability of the results obtained from data fusion is tested in a typical PMD compensator.

  6. An ab initio potential energy surface for the formic acid dimer: zero-point energy, selected anharmonic fundamental energies, and ground-state tunneling splitting calculated in relaxed 1-4-mode subspaces.

    Science.gov (United States)

    Qu, Chen; Bowman, Joel M

    2016-09-14

    We report a full-dimensional, permutationally invariant potential energy surface (PES) for the cyclic formic acid dimer. This PES is a least-squares fit to 13475 CCSD(T)-F12a/haTZ (VTZ for H and aVTZ for C and O) energies. The energy-weighted, root-mean-square fitting error is 11 cm(-1) and the barrier for the double-proton transfer on the PES is 2848 cm(-1), in good agreement with the directly-calculated ab initio value of 2853 cm(-1). The zero-point vibrational energy of 15 337 ± 7 cm(-1) is obtained from diffusion Monte Carlo calculations. Energies of fundamentals of fifteen modes are calculated using the vibrational self-consistent field and virtual-state configuration interaction method. The ground-state tunneling splitting is computed using a reduced-dimensional Hamiltonian with relaxed potentials. The highest-level, four-mode coupled calculation gives a tunneling splitting of 0.037 cm(-1), which is roughly twice the experimental value. The tunneling splittings of (DCOOH)2 and (DCOOD)2 from one to three mode calculations are, as expected, smaller than that for (HCOOH)2 and consistent with experiment.

  7. Measuring the Largest Angular Scale CMB B-mode Polarization with Galactic Foregrounds on a Cut Sky

    CERN Document Server

    Watts, Duncan J; Marriage, Tobias A; Abitbol, Maximilian H; Appel, John W; Bennett, Charles L; Chuss, David T; Eimer, Joseph R; Essinger-Hileman, Thomas; Miller, Nathan J; Rostem, Karwan; Wollack, Edward J

    2015-01-01

    We consider the effectiveness of foreground cleaning in the recovery of Cosmic Microwave Background (CMB) polarization sourced by gravitational waves for tensor-to-scalar ratios in the range $0

  8. Behaviour of a polar relaxation mode around the phase transition point in the antiferroelectric PbZrO{sub 3} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Roleder, K.; Dec, J. [Univ. of Silesia, Katowice (Poland). Inst. of Physics; Maglione, M. [Univ. of Bourgogne, Dijon (France). Lab. de Physique; Fontana, M.D. [Univ. of Metz (France). Lab. Materiaux Optiques a Proprietes Specifiques

    1996-12-02

    In measurements of the dielectric dispersion carried out on single crystals of antiferroelectric lead zirconate (PbZrO{sub 3}) a polar relaxation mode in the frequency range from 10{sup 6} to 10{sup 9} Hz has been found. Using the Cole-Cole relation for the complex {epsilon}({omega}) response the relaxation frequency and dielectric step of the mode have been determined as functions of temperature. In the paraelectric phase the squared relaxation frequency well obeys a relation f{sub r}{sup 2} {approx} (T-T{sub o}) with T{sub o} = 222.9 deg. C. The temperature dependence of the dielectric step corresponds to a sharp anomaly of the dielectric permittivity observed at the phase transition between the paraelectric and antiferroelectric states in PbZrO{sub 3}. The phase transition mechanism of order-disorder type is discussed considering a disorder of the Pb sublattice in the paraelectric phase. It should be pointed out that similar dipolar relaxation in ABO{sub 3} perovskites is known to appear only in those with ferroelectric properties. (author)

  9. Hierarchical super-structure identified by polarized light microscopy, electron microscopy and nanoindentation: Implications for the limits of biological control over the growth mode of abalone sea shells

    Directory of Open Access Journals (Sweden)

    Schneider Andreas S

    2012-09-01

    American Chemical Society 2008, 130:17519–17527]. Polarized optical microscopy revealed unprecedented super-structures in the calcitic shell part. This bears, in principle, the potential for in vivo studies, which might be useful for investigating the growth modes of nacre and other shell types.

  10. Dual-band wavelength tunable nonlinear polarization rotation mode-locked Erbium-doped fiber lasers induced by birefringence variation and gain curvature alteration.

    Science.gov (United States)

    Lin, Sheng-Fong; Lin, Gong-Ru

    2014-09-08

    With the combining effects of the fiber birefringence induced round-trip phase variation and the gain profile reshaping induced spectral filtering in the Erbium-doped fiber laser (EDFL) cavity, the mechanism corresponding to the central wavelength tunability of the EDFL passively mode-locked by nonlinear polarization rotation is explored. Bending the intracavity fiber induces the refractive index difference between orthogonal axes, which enables the dual-band central wavelength shift of 2.9 nm at 1570 nm region and up to 10.2 nm at 1600 nm region. The difference between the wavelength shifts at two bands is attributed to the gain dispersion decided by the gain spectral curvature of the EDFA, and the spacing between two switchable bands is provided by the birefringence induced variation on phase delay which causes transmittance variation. In addition, the central wavelength shift can also be controlled by varying the pumping geometry. At 1570 nm regime, an offset of up to 5.9 nm between the central wavelengths obtained under solely forward or backward pumping condition is observed, whereas the bidirectional pumping scheme effectively compensates the gain spectral reshaping effects to minimize the central wavelength shift. In contrast, the wavelength offset shrinks to only 1.1 nm when mode-locking at 1600 nm under single-sided pumping, as the gain profile strongly depends on the spatial distribution of the excited erbium ions under different pumping schemes. Except the birefringence variation and the gain spectral filtering phenomena, the gain-saturation mechanism induced refractive index change and its influence to the dual-band central wavelength tunability are also observed and analyzed.

  11. 强化规划管控实现土地利用方式根本转变%Enhancing the Management and Control over Planning and Achieving Fundamental Shift in the Mode of Land Use

    Institute of Scientific and Technical Information of China (English)

    张维宸

    2015-01-01

    土地利用规划、土地利用方式都与社会发展、科技进步息息相关,土地利用规划是土地利用方式的“预算管理”手段,土地利用规划与土地利用方式是规范和被规范的关系。从2009-2013年国有建设用地供应前10名省份的当年G D P总量来看,产粮大省耕地面积的“结伴”下行,势必对国家粮食安全带来一定冲击,强化土地利用规划管控十分重要和紧迫。实现土地利用方式根本转变,必须强化规划管控:一是要把土地利用方式根本转变作为规划的主线;二是配套制定专业用地规划和土地利用详细规划;三是建立和完善土地利用规划的法律制度体系;四是建设土地利用方式根本转变的监管体系。%Land use planning and land use mode are closely linked with social development and technological advancements. Land use planning is the means of “budget management” for land use pattern. The relationship between land use planning and land use pattern is that the former is the norm for the latter, and the latter must be according to the former. Seeing GDP gross of the top 10 provinces that the state-owned construction land were supplied for from 2009 to 2013, the arable land area in grain provinces was downward together. This situation inevitably will bring a certain impact on national food security, so it is very important and urgent for us to enhance the management and control over land use planning. The speciifc measures should be focused on the following: regarding the fundamental shift in the mode of land use as the focus of our efforts, working out special land use planning and detailed land-use planning, establishing and perfecting the legal system of land use planning, and building the supervision system to monitor the fundamental shift in the mode of land use.

  12. 基于PBL+竞争机制的“程序设计基础”课程教学模式探究%Exploration on teaching mode of program design fundamental course based on PBL+ competitive mechanism

    Institute of Scientific and Technical Information of China (English)

    彭海云; 马占欣

    2012-01-01

    Fundamental courses for the current program design focus on the existence of grammatical knowledge but at the expense of programming, debugging abilities, passive learning, not mastery, lack of competition in learning process, the main problem is proposed based on PBL + competition program design curriculum mode. In teaching methods, exercises mode, assessment methods, etc. , several aspects of the teaching process are changed to foster self-learning, innovation, competition, collaboration awareness. Through student self-assessment, peer assessment, teacher evaluation, it is found that this mode has a role to promote the student's comprehensive ability.%针对目前“程序设计基础”课程存在的侧重于语法知识的传授而忽视了编写程序、调试程序能力的培养,学生被动学习、不会融会贯通,学习过程中缺乏竞争意识等主要问题,提出基于PBL+竞争机制的程序设计课程的教学模式.在教学方法、习题模式、考核方式几个方面进行变革,改善教学过程,培养学生自学、创新、竞争、协作意识,通过学生自评、互评、教师评价,发现这种模式对学生综合能力的提高有一定促进作用.

  13. Superconductivity in the two-dimensional electron gas induced by high-energy optical phonon mode and large polarization of the SrTiO3 substrate

    Science.gov (United States)

    Rosenstein, Baruch; Shapiro, B. Ya.; Shapiro, I.; Li, Dingping

    2016-07-01

    Pairing in one-atomic-layer-thick two-dimensional electron gas (2DEG) by a single flat band of high-energy longitudinal optical phonons is considered. The polar dielectric SrTiO3 (STO) exhibits such an energetic phonon mode and the 2DEG is created both when one unit cell FeSe layer is grown on its (100 ) surface and on the interface with another dielectric like LaAlO3 (LAO). We obtain a quantitative description of both systems solving the gap equation for Tc for arbitrary Fermi energy ɛF, electron-phonon coupling λ , and the phonon frequency Ω , and direct (random-phase approximation) electron-electron repulsion strength α . The focus is on the intermediate region between the adiabatic, ɛF>>Ω , and the nonadiabatic, ɛF<<Ω , regimes. The high-temperature superconductivity in single-unit-cell FeSe/STO is possible due to a combination of three factors: high-longitudinal-optical phonon frequency, large electron-phonon coupling λ ˜0.5 , and huge dielectric constant of the substrate suppression the Coulomb repulsion. It is shown that very low density electron gas in the interfaces is still capable of generating superconductivity of the order of 0.1 K in LAO/STO.

  14. Use of mixed-mode ion exchange sorbent for the passive sampling of organic acids by polar organic chemical integrative sampler (POCIS).

    Science.gov (United States)

    Fauvelle, Vincent; Mazzella, Nicolas; Delmas, François; Madarassou, Karine; Eon, Mélissa; Budzinski, Hélène

    2012-12-18

    Acidic herbicides are increasingly monitored in freshwater, since their high solubility favors their rapid transfer to the water phase. Therefore, contaminant levels in the water can vary rapidly and passive sampling would be preferred over spot sampling to integrate all pollution events over a given exposure time. In this work, we propose to compare the conventional pharmaceutical polar organic chemical integrative sampler (POCIS) with modified POCISs containing two different receiving phases: a standard polystyrene divinylbenzene polymer with a higher specific surface area (Chromabond HR-X) and a mixed-mode anion exchange sorbent providing additional strong anion exchange interaction sites (Oasis MAX). Due to its hydrophobic character, Chromabond HR-X had little interaction with water (no sampling of acidic herbicides); whereas Oasis MAX provided acceptable sampling parameters (longer kinetic regime together with higher sampling rates). Additional experiments with POCIS-MAX showed no influence of nitrates on analyte uptakes, and linear isotherms reaching 10 μg L⁻¹, supporting the applicability of this device for the sampling of organic acids in continental water. The performance and reference compound (PRC) approach would be then applicable for POCIS-MAX if no competition is observed with other anions, especially organic acids (e.g., humic acids).

  15. Gold-nanoparticle extraction and reversed-electrode-polarity stacking mode combined to enhance capillary electrophoresis sensitivity for conjugated nucleosides and oligonucleotides containing thioether linkers.

    Science.gov (United States)

    Bosi, Valentina; Sarti, Elena; Navacchia, Maria Luisa; Perrone, Daniela; Pasti, Luisa; Cavazzini, Alberto; Capobianco, Massimo L

    2015-07-01

    We present a capillary electrophoresis method for determining two different C8-conjugated deoxyadenosines, and for oligonucleotides containing them, in which a psoralen or an acridine molecule is bonded to the base via a short alkyl chain containing sulfur ethers at both ends. The sensitivity of the micellar electrokinetic chromatography (MEKC) method was increased by using two preconcentration techniques, micro solid-phase extraction (μSPE) followed by reversed-electrode-polarity stacking mode (REPSM). Variables that affect the efficiency of the extraction in μSPE and preconcentration by REPSM, including the type and volume of extraction nanoparticle, concentration, and injection time, were investigated. Under the optimum conditions, enrichment factors obtained were in the range 360-400. The limits of detection (LODs) at a signal-to-noise ratio of 3 ranged from 2 to 5 nmol L(-1). The relative recoveries of labelled adenosines from water samples were 95-103%. The proposed method provided high enrichment factors and good precision and accuracy with a short analysis time. On the basis of the advantages of simplicity, high selectivity, high sensitivity, and good reproducibility, the proposed method may have great potential for biochemical applications.

  16. Analysis of CMOS Compatible Cu-Based TM-Pass Optical Polarizer

    KAUST Repository

    Ng, Tien Khee

    2012-02-10

    A transverse-magnetic-pass (TM-pass) optical polarizer based on Cu complementary metal-oxide-semiconductor technology platform is proposed and analyzed using the 2-D method-of-lines numerical model. In designing the optimum configuration for the polarizer, it was found that the metal-insulator-metal (MIM) polarizer structure is superior compared to the insulator-metal-insulator polarizer structure due to its higher polarization extinction ratio (PER) and low insertion loss. An optimized MIM TM-pass polarizer exhibits simulated long wavelength pass filter characteristics of > ?1.2 ?m, with fundamental TM 0 and TE 0 mode transmissivity of >70% and <5%, respectively, and with PER ?11.5 dB in the wavelength range of 1.2-1.6 ?m. The subwavelength and submicrometer features of this TM-polarizer are potentially suitable for compact and low power photonics integrated circuit implementation on silicon-based substrates. © 1989-2012 IEEE.

  17. Integrated polymer polarization rotator based on tilted laser ablation

    Science.gov (United States)

    Poulopoulos, Giannis; Kalavrouziotis, Dimitrios; Missinne, Jeroen; Bosman, Erwin; Van Steenberge, Geert; Apostolopoulos, Dimitrios; Avramopoulos, Hercules

    2017-02-01

    The ubiquitous need for compact, low-cost and mass production photonic devices, for next generation photonic enabled applications, necessitates the development of integrated components exhibiting functionalities that are, to date, carried out by free space elements or standard fiber equipment. The polarization rotator is a typical example of such tendency, as it is a crucial part of the PBS operation of future transceiver modules that leverage polarization multiplexing schemes for increasing the optical network capacity. Up to now, a variety of integrated polarization rotating concepts has been proposed and reported, relying, mainly, on special waveguide crossection configurations for achieving the rotation. Nevertheless, most of those concepts employ SiPh or III-V integration platforms, significantly increasing the fabrication complexity required for customizing the waveguide crossection, which in turn leads to either prohibitively increased cost or compromised quality and performance. In this manuscript we demonstrate the extensive design of a low-cost integrated polymer polarization rotator employing a right-trapezoidal waveguide interfaced to standard square polymer waveguides. First the crossection of the waveguide is defined by calculating and analyzing the components of the hybrid modes excited in the waveguide structure, using a Finite Difference mode solver. Mode overlaps between the fundamental polymer mode and each hybrid mode reveal the optimum lateral offset between the square polymer and the trapezoidal waveguide that ensures both minimum interface loss and maximized polarization rotation performance. The required trapezoidal waveguide length is obtained through EigenMode Expansion (EME) propagation simulations, while more than 95% maximum theoretical conversion efficiency is reported over the entire C-band, resulting to more than 13dB polarization extinction ratio. The polarization rotator design relies on the development of angled polymer waveguide

  18. Influence of polarization extinction ratio on distributed polarization coupling detection

    Institute of Scientific and Technical Information of China (English)

    XU Tian-hua; TANG Feng; JING Wen-cai; ZHANG Hong-xia; JIA Da-gong; YU Chang-song; ZHOU Ge; ZHANG Yi-mo

    2008-01-01

    Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelsonin terferorneter. This technique usually requires that only one polarization mode is excited. However, in practical measurement,the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of theincident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.

  19. Development of an enantioseparation method for novel psychoactive drugs by HPLC using a Lux(®) Cellulose-2 column in polar organic phase mode.

    Science.gov (United States)

    Taschwer, Magdalena; Grascher, Jörg; Schmid, Martin G

    2017-01-01

    Since the last decade, the hype of the recreational use of novel psychoactive drugs is still on its top in entire Europe. Every year, new derivatives enter the drug market and enlarge the broad spectrum of misused drugs. Many of these compounds contain a stereogenic centre and therefore two enantiomers exist. It is obvious that the pharmacological potency of the isomers differ as it is already known from various pharmaceutical ingredients. Therefore, the development of analytical methods for the chiral separation of new psychoactive substances is of great medical and forensic interest. The aim of this study was to establish an enantioseparation method, which is applicable at equal conditions for different drug compound classes including cathinones, amphetamines, benzofurans, thiophenes, phenidine and phenidate derivatives. A commercially available Lux(®) Cellulose-2 column consisting of cellulose tris(3-chloro-4-methylphenylcarbamate) coated on silica gel was found to be appropriate for the chiral separation of the mentioned drug classes. Experiments were performed under isocratic conditions in polar organic phase mode using UV-detection. With a mobile phase consisting of acetonitrile:isopropanol:diethylamine:formic acid (100%) (95:5:0.1:0.1) 40 out of 43 psychoactive compounds were successfully baseline or partially separated. 3-Fluoroamphetamine, 4-fluoroamphetamine and 1-(benzofuran-6-yl)-N-ethylpropan-2-amine were not chirally separated. The established method enabled enantioseparation of a broad spectrum of different psychoactive compounds under equal conditions. Forty of forty-three compounds were separated in their enantiomers, thus this method has a wide applicability for the enantioseparation of novel psychoactive drugs.

  20. Simultaneous quantitative determination of celecoxib and its two metabolites using liquid chromatography-tandem mass spectrometry in alternating polarity switching mode.

    Science.gov (United States)

    Oh, Hyun-A; Kim, Donghak; Lee, Soo Hyun; Jung, Byung Hwa

    2015-03-25

    A simple and rapid quantitative analytical method for the simultaneous detection of celecoxib and its two main metabolites, hydroxycelecoxib (celecoxib-OH) and celecoxib carboxylic acid (celecoxib-COOH), in rat plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The plasma sample was prepared through simple protein precipitation, and the reconstitution solution (0.1% formic acid in 50% methanol) was optimized to achieve the best peak shape and recovery. The analytes were separated using an Atlantis T3 column (2.1 mm × 100 mm, 3 μm), and the mobile phase was composed of 10 mM ammonium formate in either 5% acetonitrile or 95% acetonitrile. The detection of the analytes was performed in alternating polarity switching mode using electrospray ionization. As celecoxib-OH and celecoxib-COOH were slightly unstable following freeze-thaw cycles and long-term storage at -80°C in stability tests, every analysis was carefully conducted with one-freeze thaw cycle and a short storage duration (<1 week). Acceptable accuracy (<15%) and precision (<15%) were obtained in intra- and inter-day validations. The method was successfully applied to the pharmacokinetic study of celecoxib, celecoxib-OH and celecoxib-COOH following the oral administration of celecoxib in rats at a dose of 10mg/kg. Comparing the related pharmacokinetic parameters of celecoxib and its metabolites, celecoxib was quickly metabolized into celecoxib-OH and subsequently converted to celecoxib-COOH in short intervals. The AUCs for the two metabolites were less than 10% of that for celecoxib, indicating that the rate of celecoxib metabolism was low.

  1. Exploring transverse pattern formation in a dual-polarization self-mode-locked monolithic Yb: KGW laser and generating a 25-GHz sub-picosecond vortex beam via gain competition.

    Science.gov (United States)

    Chang, M T; Liang, H C; Su, K W; Chen, Y F

    2016-04-18

    Formation of transverse modes in a dual-polarization self-mode-locked monolithic Yb: KGW laser under high-power pumping is thoroughly explored. It is experimentally observed that the polarization-resolved transverse patterns are considerably affected by the pump location in the transverse plane of the gain medium. In contrast, the longitudinal self-mode-locking is nearly undisturbed by the pump position, even under the high-power pumping. Under central pumping, a vortex beam of the Laguerre-Gaussian LGp,l mode with p = 1 and l = 1 can be efficiently generated through the process of the gain competition with a sub-picosecond pulse train at 25.3 GHz and the output power can be up to 1.45 W at a pump power of 10.0 W. Under off-center pumping, the symmetry breaking causes the transverse patterns to be dominated by the high-order Hermite-Gaussian modes. Numerical analyses are further performed to manifest the symmetry breaking induced by the off-center pumping.

  2. 基于混合学习法的大学计算机基础教学模式初探%Study on Teaching Mode of Fundamental Computer Based on Blended Learning

    Institute of Scientific and Technical Information of China (English)

    李瑞芳; 刘华蓥; 王莉利; 杨王黎

    2014-01-01

    本文针对目前大学计算机基础教育中学生学习兴趣低、主体能动性差等问题,提出了基于混合学习法的计算机基础教学模式,旨在最大限度地发挥学生的主体能动性,培养学生的自主学习能力和团队协作精神。实践证明,混合学习法有效地提高了不同水平学生的信息素养,取得了很好的授课质量和效果。%In view of the problems of students' lack of interest and motivation about fundamental computer course, the teaching mode based on blended learning is put forward, which is de-signed to maximize students' learning initiative,cultivate students' self-learning ability and teamwork sense. Practice has proved, blended learning method effectively improves students' informa-tion literacy of different levels, and achieved very good teaching quality and effectiveness.

  3. Improved Assignments of the Vibrational Fundamental Modes of ortho-, meta-, and para-xylene Using Gas- and Liquid-Phase Infrared and Raman Spectra Combined with ab initio Calculations: Quantitative Gas-Phase Infrared Spectra for Detection

    Energy Technology Data Exchange (ETDEWEB)

    Lindenmaier, Rodica; Scharko, Nicole K.; Tonkyn, Russell G.; Nguyen, Kiet T.; Williams, Stephen D.; Johnson, Timothy J.

    2017-12-05

    Xylenes contain a blend of the ortho-, meta-, and para- isomers, and all are abundant contaminants in the ground, surface waters, and air. To better characterize xylene and to better enable its detection, we report high quality quantitative vapor-phase infrared spectra of all three isomers over the 540˗6500 cm-1 range. All fundamental vibrational modes are assigned based on these vapor-phase infrared spectra, liquid-phase infrared and Raman spectra, along with density functional theory (DFT), ab initio MP2 and high energy-accuracy compound theoretical model (W1BD) calculations. Both MP2 and DFT predict a single conformer with C2v symmetry for ortho-xylene, and two conformers each for meta- and para-xylene, depending on the preferred orientations of the methyl groups. For meta-xylene the two conformers have Cs and C2 symmetry, and for para-xylene these conformers have C2v or C2h symmetry. Since the relative population of the two conformers is approximately 50% for both isomers and predicted frequencies and intensities are very similar for each conformer, we made an arbitrary choice to discuss the Cs conformer for meta-xylene and the C2v conformer for para-xylene. We report integrated band intensities for all isomers. Using the quantitative infrared data, we determine the global warming potential values of each isomer and discuss potential bands for atmospheric monitoring.

  4. Analysis of the multipactor effect in circular waveguides excited by two orthogonal polarization waves

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, A. M.; Boria, V. E. [Departamento de Comunicaciones-iTEAM, Universidad Politécnica de Valencia Camino de Vera s/n, 46022 Valencia (Spain); Gimeno, B. [Departamento de Física Aplicada y Electromagnetismo-ICMUV, Universitat de València c/Dr. Moliner, 50, 46100 Valencia (Spain); Anza, S.; Vicente, C.; Gil, J. [Aurora Software and Testing S.L., Edificio de Desarrollo Empresarial 9B, Universidad Politécnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)

    2014-08-15

    Circular waveguides, either employed as resonant cavities or as irises connecting adjacent guides, are widely present in many passive components used in different applications (i.e., particle accelerators and satellite subsystems). In this paper, we present the study of the multipactor effect in circular waveguides considering the coexistence of the two polarizations of the fundamental TE{sub 11} circular waveguide mode. For a better understanding of the problem, only low multipactor orders have been explored as a function of the polarization ellipse eccentricity. Special attention has been paid to the linear and circular polarizations, but other more general configurations have also been explored.

  5. Crossing characteristics of lamb wave modes in [001]{sub c} and [011]{sub c} polarized Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} crystal plates

    Energy Technology Data Exchange (ETDEWEB)

    Chen Chuanwen, E-mail: cwchen@hqu.edu.cn [College of Information Science and Engineering, Huaqiao University(Xiamen), Xiamen 361021 (China); Xiang Yang [College of Information Science and Engineering, Huaqiao University(Xiamen), Xiamen 361021 (China)

    2012-04-01

    Multiple crossings of Lamb modes found in [001]{sub c} and [011]{sub c} polarized (1-x)Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-xPbTiO{sub 3} (PMN-xPT, x=0.33 and 0.29, respectively) plates have been studied by comparing their slowness patterns with their dispersion patterns. Multiple bandgaps and crossings of Lamb wave dispersion curves are directly related to the multivalued curves in region II, and a pair of complex conjugate b{sup 2} values in region I of their slowness curves. An expression composed of elastic and piezoelectric constants has been derived to judge whether S{sub 0} and A{sub 0} modes cross with each other. This expression can be greatly simplified for non-piezoelectric materials, and there are no crossings of Lamb modes for isotropic materials.

  6. EFECTOS DE LA DISPERSIÓN POR MODO DE POLARIZACIÓN (PMD EN LA PROPAGACIÓN DE PULSOS A TRAVÉS DE FIBRAS ÓPTICAS EFFECTS OF POLARIZATION MODE DISPERSION (PMD ON PROPAGATION OF OPTICAL PULSES IN OPTICAL FIBERS

    Directory of Open Access Journals (Sweden)

    Ariel Leiva L

    2007-12-01

    Full Text Available En este trabajo se revisan los conceptos fundamentales de la dispersión por modo de polarización (PMD: Polarization Mode Dispersion que ocurre en fibras ópticas. PMD produce ensanchamientos aleatorios de los pulsos ópticos transmitidos a través de una fibra óptica y su efecto es considerable para velocidades de transmisión digital iguales o superiores a 10 Gbps. Se revisa la teoría de PMD y se plantea la relevancia de caracterizar el fenómeno en transmisión por fibra óptica, concluyéndose con un método de simulación de la propagación de pulsos afectados por PMD. Este trabajo constituye un punto de partida para posteriores análisis de los efectos de PMD en sistemas de transmisión, para su compensación y mediciónThis work reviews the fundamental concepts of polarization mode dispersion (PMD occurring in optical fibers. PMD broadens optical pulses transmitted through an optical fiber at random and its effect is significant for bit rates equal or exceeding 10 Gbps. The theory of PMD and relevance of characterizing this phenomenon in optical fiber transmission is presented, concluding with a simulation model of the optical pulse propagation, subject to PMD. This provides a starting point for further analysis of the effects of PMD in transmission systems and how to measure and compensate these

  7. A mode converter to generate a Gaussian-like mode for injection into the VENUS electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Lyneis, C., E-mail: CMLyneis@lbl.gov; Benitez, J.; Hodgkinson, A.; Strohmeier, M.; Todd, D. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Plaum, B. [Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie (IGVP), Stuttgart (Germany); Thuillier, T. [Laboratoire de Physique Subatomique et de Cosmologie, Université Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut Polytechnique de Grenoble, 53 rue des martyrs 38026 Grenoble cedex (France)

    2014-02-15

    A number of superconducting electron cyclotron resonance (ECR) ion sources use gyrotrons at either 24 or 28 GHz for ECR heating. In these systems, the microwave power is launched into the plasma using the TE{sub 01} circular waveguide mode. This is fundamentally different and may be less efficient than the typical rectangular, linearly polarized TE{sub 10} mode used for launching waves at lower frequencies. To improve the 28 GHz microwave coupling in VENUS, a TE{sub 01}-HE{sub 11} mode conversion system has been built to test launching HE{sub 11} microwave power into the plasma chamber. The HE{sub 11} mode is a quasi-Gaussian, linearly polarized mode, which should couple strongly to the plasma electrons. The mode conversion is done in two steps. First, a 0.66 m long “snake” converts the TE{sub 01} mode to the TE{sub 11} mode. Second, a corrugated circular waveguide excites the HE{sub 11} mode, which is launched directly into the plasma chamber. The design concept draws on the development of similar devices used in tokamaks and stellerators. The first tests of the new coupling system are described below.

  8. Fundamentals of plastic optical fibers

    CERN Document Server

    Koike, Yasuhiro

    2014-01-01

    Polymer photonics is an interdisciplinary field which demands excellence both in optics (photonics) and materials science (polymer). However, theses disciplines have developed independently, and therefore the demand for a comprehensive work featuring the fundamentals of photonic polymers is greater than ever.This volume focuses on Polymer Optical Fiber and their applications. The first part of the book introduces typical optical fibers according to their classifications of material, propagating mode, and structure. Optical properties, the high bandwidth POF and transmission loss are discussed,

  9. Principal modes in fiber amplifiers

    CERN Document Server

    Fridman, Moti; Dubinskii, Mark; Friesem, Asher A; Davidson, Nir

    2010-01-01

    The dynamics of the state of polarization in single mode and multimode fiber amplifiers are presented. The experimental results reveal that although the state of polarizations at the output can vary over a large range when changing the temperatures of the fiber amplifiers, the variations are significantly reduced when resorting to the principal states of polarization in single mode fiber amplifiers and principal modes in multimode fiber amplifiers.

  10. FInvestigation of enhancement mode HfO2 insulated N-polarity GaN/InN/GaN/In0.9Al0.1N heterostructure MISHEMT for high-frequency applications

    Science.gov (United States)

    Mohanbabu, A.; Mohankumar, N.; Godwin Raj, D.; Sarkar, Partha

    2017-08-01

    In this paper, we examined normally-OFF N-polar InN-channel Metal insulated semiconductor high-electron mobility transistors (MISHEMTs) device with a relaxed In0.9Al0.1N buffer layer. In addition, the enhancement-mode operation of the N-polar structure was investigated. The effect of scaling in N-polar MISHEMT, such as the dielectric and the channel thickness, alter the electrical behavior of the device. We have achieved a maximum drain current of 1.17 A/mm, threshold voltage (VT) =0.728 V, transconductance (gm) of 2.9 S mm-1, high ION/IOFF current ratio of 3.23×103, lowest ON-state resistance (RON) of 0.41 Ω mm and an intrinsic delay time (τ) of 1.456 Fs along with high-frequency performance with ft/ fmaxof 90 GHz/109 GHz and 180 GHz/260 GHz for TCH =0.5 nm at Vds =0.5 V and 1.0 V. The numerically simulated results of highly confined GaN/InN/GaN/In0.9Al0.1N heterostructure MISHEMT exhibits outstanding potential as one of the possibility to replace presently used N-polar MISHEMTs for delivering high power density and frequency at RF/power amplifier applications.

  11. 基于椭圆偏振光注入垂直腔表面发射激光器的正交偏振模式单周期振荡产生两路光子微波∗%Two channel photonic microwave generation based on period-one oscillations of two orthogonally polar-ized modes in a vertical-cavity surface-emitting laser subjected to an elliptically polarized optical injection

    Institute of Scientific and Technical Information of China (English)

    周娅; 吴正茂; 樊利; 孙波; 何洋; 夏光琼

    2015-01-01

    Previous investigations demonstrated that a semiconductor laser subjected to optical injection can realize period-one (P1) oscillation output under suitable operational parameters, which can be used to obtain high quality photonic microwave. In this paper, we propose a scheme for simultaneously generating two channel photonic microwave based on the P1 oscillations of two orthogonally polarization modes in a vertical-cavity surface-emitting laser (VCSEL) subjected to an elliptical polarization optical injection, and the relevant characteristics of obtained photonic microwave are numerically simulated and analyzed. The results show that under suitable operational parameters, a free-running VCSEL (named master VCSEL, M-VCSEL) can output an elliptical polarization light in which both X and Y polarization components of the elliptical polarization light oscillate at the same frequency. By using the elliptical polarization light from the M-VCSEL as an injection light into another VCSEL (named slave VCSEL, S-VCSEL), both two polarization components of the S-VCSEL can be driven into P1 oscillation through selecting suitable injection strength under a fixed frequency detuning between the M-VCSEL and the S-VCSEL. Based on the P1 oscillation, two orthogonally photonic microwave signals can be obtained. With the increase of the injection strength from the M-VCSEL, the frequency of photonic microwave shows a gradually increasing trend while the power of photonic microwave displays an increasing process accompanied by slight ripples. Combining the distribution mappings of the frequency, the power, and the amplitude difference between the first sideband and the second sideband of the photonic microwave in the parameter space of the injection strength and the frequency detuning, certain regions with optimally operational parameters can be determined for acquiring high quality photonic microwave.

  12. Polarity reversion of the operation mode of HfO2-based resistive random access memory devices by inserting Hf metal layer.

    Science.gov (United States)

    Peng, Ching-Shiang; Chang, Wen-Yuan; Lin, Ming-Ho; Chen, Wei-Su; Chen, Frederick; Tsai, Ming-Jinn

    2013-03-01

    The reversion of polarity within bipolar resistive switching operation occurs in Pt/HfO2/TiN and Pt/Hf/HfO2/TiN resistive random access memory devices. This reversion of voltage polarity is the result of interface generation which induces a conduction mechanism transformation from Poole-Frenkel emission to space charge limited current mechanism. To prove the reversion of polarity, this study uses curve fitting of I-V relations to verify the conduction mechanism theoretically and physical analysis to verify the oxygen ion distribution practically. The proposed Pt/Hf/HfO2/TiN devices exhibit good resistive switching characteristics, such as good uniformity, low voltage operation, robust endurance (10(3) dc sweep), and long retention (3 x 10(4) s at 85 degrees C).

  13. Rayleigh waves ellipticity and mode mis-identification in multi-channel analysis of surface waves

    DEFF Research Database (Denmark)

    Boaga, Jacopo; Cassiani, Giorgio; Strobbia, Claudio

    dispersion curve which is then inverted. Typically, single component vertical and multi channel receivers are used. In most cases the inversion of the dispersion properties is carried out assuming that the experimental dispersion curve corresponds to a single mode, mostly the fundamental Rayleigh mode......-identification known as ‘osculation’ (‘kissing’). In general it is called ‘osculation point’ the point where the energy peak shifts at low frequencies from the fundamental to the first higher mode. This jump occurs, with a continuous smooth transition, around a well-define frequency where the two modes get very close...... the vertical component of ground motion, as the mode osculation is linked to the Rayleigh wave ellipticity polarization, and therefore we conclude that multi-component data, using also horizontal receivers, can help discern the multi-modal nature of surface waves. Finally we introduce a-priori detectors...

  14. Retinal polarization-sensitive optical coherence tomography at 1060 nm with 350 kHz A-scan rate using an Fourier domain mode locked laser

    DEFF Research Database (Denmark)

    Torzicky, Teresa; Marschall, Sebastian; Pircher, Michael;

    2013-01-01

    , averaging several two-dimensional frames allows the generation of high-definition B-scans without the use of an eye-tracking system. The increased penetration depth of the system, which is caused by the longer probing beam wavelength, is beneficial for imaging choroidal and scleral structures and allows...... automated segmentation of these layers based on their polarization characteristics....

  15. Saturation of the f -mode instability in neutron stars: Theoretical framework

    Science.gov (United States)

    Pnigouras, Pantelis; Kokkotas, Kostas D.

    2015-10-01

    The basic formulation describing quadratic mode coupling in rotating Newtonian stars is presented, focusing on polar modes. Due to the Chandrasekhar-Friedman-Schutz mechanism, the f -mode (fundamental oscillation) is driven unstable by the emission of gravitational waves. If the star falls inside the so-called instability window, the mode's amplitude grows exponentially, until it is halted by nonlinear effects. Quadratic perturbations form three-mode networks inside the star, which evolve as coupled oscillators, exchanging energy. Coupling of the unstable f -mode to other (stable) modes can lead to a parametric resonance and the subsequent saturation of its amplitude, thus suppressing the instability. The saturation point determines the amplitude of the gravitational-wave signal obtained from an individual source, as well as the evolutionary path of the latter inside the instability window.

  16. Saturation of the f-mode instability in neutron stars: I. Theoretical framework

    CERN Document Server

    Pnigouras, Pantelis

    2015-01-01

    The basic formulation describing quadratic mode coupling in rotating Newtonian stars is presented, focusing on polar modes. Due to the Chandrasekhar-Friedman-Schutz mechanism, the f-mode (fundamental oscillation) is driven unstable by the emission of gravitational waves. If the star falls inside the so-called instability window, the mode's amplitude grows exponentially, until it is halted by non-linear effects. Quadratic perturbations form three-mode networks inside the star, which evolve as coupled oscillators, exchanging energy. Coupling of the unstable f-mode to other (stable) modes can lead to a parametric resonance and the subsequent saturation of its amplitude, thus suppressing the instability. The saturation point determines the amplitude of the gravitational-wave signal obtained from an individual source, as well as the evolutionary path of the latter inside the instability window.

  17. Exchange Rates and Fundamentals.

    Science.gov (United States)

    Engel, Charles; West, Kenneth D.

    2005-01-01

    We show analytically that in a rational expectations present-value model, an asset price manifests near-random walk behavior if fundamentals are I (1) and the factor for discounting future fundamentals is near one. We argue that this result helps explain the well-known puzzle that fundamental variables such as relative money supplies, outputs,…

  18. Program for fundamental and applied research of fuel cells in VNIIEF

    Energy Technology Data Exchange (ETDEWEB)

    Anisin, A.V.; Borisseonock, V.A.; Novitskii, Y.Z.; Potyomckin, G.A.

    1996-04-01

    According to VNIIEF the integral part of development of fuel cell power plants is fundamental and applied research. This paper describes areas of research on molten carbonate fuel cells. Topics include the development of mathematical models for porous electrodes, thin film electrolytes, the possibility of solid nickel anodes, model of activation polarization of anode, electrolyte with high solubility of oxygen. Other areas include research on a stationary mode of stack operation, anticorrosion coatings, impedance diagnostic methods, ultrasound diagnostics, radiation treatments, an air aluminium cell, and alternative catalysts for low temperature fuel cells.

  19. Investigation of low-energy dipole modes in the heavy deformed nucleus {sup 154}Sm via inelastic polarized proton scattering at zero degree

    Energy Technology Data Exchange (ETDEWEB)

    Krugmann, Andreas; Martin, Dirk; Neumann-Cosel, Peter von; Pietralla, Norbert; Poltoratska, Iryna; Ponomarev, Vladimir [Technische Univ. Darmstadt (Germany). Inst. fuer Kernphysik; Tamii, Atsushi [RCNP, Osaka University (Japan); Iwamoto, Chihiro [Konan University (Japan); Yoshida, Kenichi [Niigata University (Japan); Collaboration: E350-Collaboration

    2013-07-01

    Polarized proton scattering has been measured on the heavy deformed nucleus {sup 154}Sm at extreme forward angles with 300 MeV protons at RCNP, Osaka. The aim is to investigate the impact of ground state deformation on the properties of the pygmy dipole resonance (PDR) and the spin M1 resonance claimed to show a double-hump structure in heavy deformed nuclei. The (p,p') cross sections can be decomposed into E1 and M1 parts in two independent ways based either on a multipole decomposition of the cross sections or spin transfer observables. The analysis of polarization transfer observables shows dominant non-spinflip cross sections in the excitation energy region 5-9 MeV with a resonance structure interpreted as the PDR, while the spinflip M1 strength shows a broad distribution between 5 and 10 MeV.

  20. High-sensitivity capillary electrophoresis method for monitoring purine nucleoside phosphorylase and adenosine deaminase reactions by a reversed electrode polarity switching mode.

    Science.gov (United States)

    Iqbal, Jamshed; Müller, Christa E

    2011-07-22

    A simple, efficient, and highly sensitive in-line CE method was developed for the characterization and for inhibition studies of the nucleoside-metabolizing enzymes purine nucleoside phosphorylase (PNP) and adenosine deaminase (ADA) present in membrane preparations of human 1539 melanoma cells. After filling the running buffer (50 mM borate buffer, 100 mM SDS, pH 9.10) into a fused-silica capillary (50 cm effective length × 75 μm), a large sample volume was loaded by hydrodynamic injection (5 psi, 36 s), followed by the removal of the large plug of sample matrix from the capillary using polarity switching (-20 kV). The current was monitored and the polarity was reversed when 95% of the current had been recovered. The separation of the neutral analytes (nucleosides and nucleobases) was performed by applying a voltage of 15 kV. An about 10-fold improvement of sensitivity for the five investigated analytes (adenosine, inosine, adenine, hypoxanthine, xanthine) was achieved by large-volume stacking with polarity switching when compared with CE without stacking. For inosine and adenine detection limits as low as 60 nM were achieved. To the best of our knowledge, this represents the highest sensitivity for nucleoside and nucleobase analysis using CE with UV detection reported so far. The Michaelis-Menten constants (K(m)) for PNP and ADA and the inhibition constants (K(i)) for standard inhibitors determined with the new method were consistent with literature data.

  1. Sub-100 fs pulses from an all-polarization maintaining Yb-fiber oscillator with an anomalous dispersion higher-order-mode fiber

    DEFF Research Database (Denmark)

    Verhoef, A. J.; Zhu, L.; Israelsen, Stine Møller;

    2015-01-01

    , was investigated for different settings of the intracavity dispersion. When the cavity is operated with close to zero net dispersion, highly stable 0.5-nJ pulses externally compressed to sub-100-fs are generated. These are to our knowledge the shortest pulses generated from an all-polarization-maintaining Yb......-fiber oscillator. The spectral phase of the output pulses is well behaved and can be compensated such that wing-free Fourier transform limited pulses can be obtained. Further reduction of the net intracavity third order dispersion will allow generating broader output spectra and consequently shorter pulses......, without sacrificing pulse fidelity....

  2. An insight into polarization states of solid-state organic lasers

    CERN Document Server

    Gozhyk, I; Meallet-Renault, R; Dvorko, M; Pansu, R; Audibert, J -F; Brosseau, A; Lafargue, C; Tsvirkun, V; Lozenko, S; Forget, S; Chenais, S; Ulysse, C; Zyss, J; Lebental, M

    2012-01-01

    The polarization states of lasers are crucial issues both for practical applications and fundamental research. In general, they depend in a combined manner on the properties of the gain material and on the structure of the electromagnetic modes. In this paper, we address this issue in the case of solid-state organic lasers, a technology which enables to vary independently gain and mode properties. Different kinds of resonators are investigated: in-plane micro-resonators with Fabry-Perot, square, pentagon, stadium, disk, and kite shapes, and external vertical resonators. The degree of polarization P is measured in each case. It is shown that although TE modes prevail generally (P>0), kite-shaped micro-laser generates negative values for P, i.e. a flip of the dominant polarization which becomes mostly TM polarized. We at last investigated two degrees of freedom that are available to tailor the polarization of organic lasers, in addition to the pump polarization and the resonator geometry: upon using resonant en...

  3. BICEP2 / Keck Array V: Measurements of B-mode Polarization at Degree Angular Scales and 150 GHz by the Keck Array

    CERN Document Server

    Ade, P A R; Aikin, R W; Alexander, K D; Barkats, D; Benton, S J; Bischoff, C A; Bock, J J; Brevik, J A; Buder, I; Bullock, E; Buza, V; Connors, J; Crill, B P; Dowell, C D; Dvorkin, C; Duband, L; Filippini, J P; Fliescher, S; Golwala, S R; Halpern, M; Hasselfield, M; Hildebrandt, S R; Hilton, G C; Hristov, V V; Hui, H; Irwin, K D; Karkare, K S; Kaufman, J P; Keating, B G; Kefeli, S; Kernasovskiy, S A; Kovac, J M; Kuo, C L; Leitch, E M; Lueker, M; Mason, P; Megerian, K G; Netterfield, C B; Nguyen, H T; O'Brient, R; Ogburn, R W; Orlando, A; Pryke, C; Reintsema, C D; Richter, S; Schwarz, R; Sheehy, C D; Staniszewski, Z K; Sudiwala, R V; Teply, G P; Thompson, K L; Tolan, J E; Turner, A D; Vieregg, A G; Weber, A C; Willmert, J; Wong, C L; Yoon, K W

    2015-01-01

    The Keck Array is a system of cosmic microwave background (CMB) polarimeters, each similar to the BICEP2 experiment. In this paper we report results from the 2012 and 2013 observing seasons, during which the Keck Array consisted of five receivers all operating in the same (150 GHz) frequency band and observing field as BICEP2. We again find an excess of B-mode power over the lensed-$\\Lambda$CDM expectation of $> 5 \\sigma$ in the range $30 6\\sigma$.

  4. Fundamentals of gas dynamics

    CERN Document Server

    Babu, V

    2014-01-01

    Fundamentals of Gas Dynamics, Second Edition isa comprehensively updated new edition and now includes a chapter on the gas dynamics of steam. It covers the fundamental concepts and governing equations of different flows, and includes end of chapter exercises based on the practical applications. A number of useful tables on the thermodynamic properties of steam are also included.Fundamentals of Gas Dynamics, Second Edition begins with an introduction to compressible and incompressible flows before covering the fundamentals of one dimensional flows and normal shock wav

  5. Crystal science fundamentals

    OpenAIRE

    Ramachandran, V.; Halfpenny, PJ; Roberts, KJ

    2017-01-01

    The fundamentals of crystal science notably crystallography, crystal chemistry, crystal defects, crystal morphology and the surface chemistry of crystals are introduced with particular emphasis on organic crystals.

  6. A switched ring Stark decelerator for both light and heavy polar molecules

    Science.gov (United States)

    Hou, Shunyong; Wang, Qin; Deng, Lianzhong; Yin, Jianping

    2016-03-01

    There is increasing interest in cold heavy polar molecular species for their applications in fundamental physics, such as the tests of the electron’s electric dipole moment. Here we propose a switched ring Stark decelerator suitable for slowing both light and heavy polar molecules. Two typical polar molecular species, ND3 and 205TlF, are employed to test the feasibility of our scheme with the help of trajectory calculation. Our proposed scheme is found to share many advantages with the state-of-the-art traveling wave decelerator, yet with relatively simple electronics and flexible operation modes. Sub-millikelvin molecular samples can be conveniently obtained in our decelerator using a combined operation mode. These monochromatic beams are ideal starting points for precise studies of molecular collision, cold chemistry and high-resolution spectroscopy.

  7. Frequency splitting of polarization eigenmodes in microscopic Fabry-Perot cavities

    CERN Document Server

    Uphoff, Manuel; Rempe, Gerhard; Ritter, Stephan

    2014-01-01

    We study the frequency splitting of the polarization eigenmodes of the fundamental transverse mode in CO2 laser-machined, high-finesse optical Fabry-Perot cavities and investigate the influence of the geometry of the cavity mirrors. Their highly reflective surfaces are typically not rotationally symmetric, but have slightly different radii of curvature along two principal axes. We observe that the eccentricity of such elliptical mirrors lifts the degeneracy of the polarization eigenmodes. The impact of the eccentricity increases for smaller radii of curvature. A model derived from corrections to the paraxial resonator theory is in excellent agreement with measurements, showing that geometric effects are the main source of the frequency splitting of polarization modes for the studied type of microscopic cavity. By rotation of one of the mirrors around the cavity axis, the splitting can be tuned. In the case of an identical differential phase shift per mirror it can even be eliminated, despite a nonvanishing ec...

  8. Vectorial optical fields fundamentals and applications

    CERN Document Server

    2014-01-01

    Polarization is a vector nature of light that plays an important role in optical science and engineering. While existing textbook treatments of light assume beams with spatially homogeneous polarization, there is an increasing interest in vectorial optical fields with spatially engineered states of polarization. New effects and phenomena have been predicted and observed for light beams with these unconventional polarization states. This edited review volume aims to provide a comprehensive overview and summarize the latest developments in this important emerging field of optics. This book will cover the fundamentals including mathematical and physical descriptions, experimental generation, manipulation, focusing, propagation, and the applications of the engineered vectorial optical fields in focal field engineering, plasmonic focusing and optical antenna, single molecular imaging, optical tweezers/trapping, as well as optical measurements and instrumentations. Readership: Students, professionals, post-graduat...

  9. VCSELs Fundamentals, Technology and Applications of Vertical-Cavity Surface-Emitting Lasers

    CERN Document Server

    2013-01-01

    The huge progress which has been achieved in the field is covered here, in the first comprehensive monograph on vertical-cavity surface-emitting lasers (VCSELs) since eight years. Apart from chapters reviewing the research field and the laser fundamentals, there are comprehensive updates on red and blue emitting VCSELs, telecommunication VCSELs, optical transceivers, and parallel-optical links for computer interconnects. Entirely new contributions are made to the fields of vectorial three-dimensional optical modeling, single-mode VCSELs, polarization control, polarization dynamics, very-high-speed design, high-power emission, use of high-contrast gratings, GaInNAsSb long-wavelength VCSELs, optical video links, VCSELs for optical mice and sensing, as well as VCSEL-based laser printing. The book appeals to researchers, optical engineers and graduate students.

  10. Fundamentals of Physics

    Science.gov (United States)

    Halliday, David; Resnick, Robert; Walker, Jearl

    2003-01-01

    No other book on the market today can match the success of Halliday, Resnick and Walker's Fundamentals of Physics! In a breezy, easy-to-understand style the book offers a solid understanding of fundamental physics concepts, and helps readers apply this conceptual understanding to quantitative problem solving.

  11. Dependence and Fundamentality

    Directory of Open Access Journals (Sweden)

    Justin Zylstra

    2014-12-01

    Full Text Available I argue that dependence is neither necessary nor sufficient for relative fundamentality. I then introduce the notion of 'likeness in nature' and provide an account of relative fundamentality in terms of it and the notion of dependence. Finally, I discuss some puzzles that arise in Aristotle's Categories, to which the theory developed is applied.

  12. Performance Analysis of Multiradio Transmitter with Polar or Cartesian Architectures Associated with High Efficiency Switched-Mode Power Amplifiers (invited paper

    Directory of Open Access Journals (Sweden)

    F. Robert

    2010-12-01

    Full Text Available This paper deals with wireless multi-radio transmitter architectures operating in the frequency band of 800 MHz – 6 GHz. As a consequence of the constant evolution in the communication systems, mobile transmitters must be able to operate at different frequency bands and modes according to existing standards specifications. The concept of a unique multiradio architecture is an evolution of the multistandard transceiver characterized by a parallelization of circuits for each standard. Multi-radio concept optimizes surface and power consumption. Transmitter architectures using sampling techniques and baseband ΣΔ or PWM coding of signals before their amplification appear as good candidates for multiradio transmitters for several reasons. They allow using high efficiency power amplifiers such as switched-mode PAs. They are highly flexible and easy to integrate because of their digital nature. But when the transmitter efficiency is considered, many elements have to be taken into account: signal coding efficiency, PA efficiency, RF filter. This paper investigates the interest of these architectures for a multiradio transmitter able to support existing wireless communications standards between 800 MHz and 6 GHz. It evaluates and compares the different possible architectures for WiMAX and LTE standards in terms of signal quality and transmitter power efficiency.

  13. Materials Fundamentals of Gate Dielectrics

    CERN Document Server

    Demkov, Alexander A

    2006-01-01

    This book presents materials fundamentals of novel gate dielectrics that are being introduced into semiconductor manufacturing to ensure the continuous scalling of the CMOS devices. This is a very fast evolving field of research so we choose to focus on the basic understanding of the structure, thermodunamics, and electronic properties of these materials that determine their performance in device applications. Most of these materials are transition metal oxides. Ironically, the d-orbitals responsible for the high dielectric constant cause sever integration difficulties thus intrinsically limiting high-k dielectrics. Though new in the electronics industry many of these materials are wel known in the field of ceramics, and we describe this unique connection. The complexity of the structure-property relations in TM oxides makes the use of the state of the art first-principles calculations necessary. Several chapters give a detailed description of the modern theory of polarization, and heterojunction band discont...

  14. Far-infrared spectra of dimethyl-ether and its 13C enriched isotopologues: The fundamental band of the C-O-C in plane bending mode, ν7

    Science.gov (United States)

    Kutzer, P.; Weismann, D.; Waßmuth, B.; Pirali, O.; Roy, P.; Yamada, K. M. T.; Giesen, T. F.

    2016-11-01

    We recorded the ν7 fundamental band of dimethyl-ether around 400 cm-1 for the normal and 13C-enriched isotopologues using the Fourier transform spectrometer at the SOLEIL Synchrotron facility. For all three species P, Q and R branch-transitions up to J = 20 and Ka = 5 were assigned and the band origins and rotational parameters of Watson's A-reduced Hamiltonian have been determined by the least-squares fitting procedure. The line splitting due to the torsional tunneling is observed for low J transitions, which is attributed to the ro-vibrational interaction with the excited torsional states.

  15. Low-loss polarization-maintaining fusion splicing of single-mode fibers and hollow-core photonic crystal fibers, relevant for monolithic fiber laser pulse compression

    DEFF Research Database (Denmark)

    Kristensen, Jesper Toft; Houmann, Andreas; Liu, Xiaomin;

    2008-01-01

    B. The reciprocal HC-PCF-to-PM-SMF splice loss is found to be 2.19 ± 0.33 dB, which is caused by the mode evolution in HC-PCF. The return loss in both cases was measured to be −14 dB. We show that a splice defect is caused by the HC-PCF cleave defect, and the lossy splice can be predicted at an early stage...... of the splicing process. We also demonstrate that the higher splice loss compromises the PM properties of the splice. Our splicing technique was successfully applied to the realization of a low-loss, environmentally stable monolithic PM fiber laser pulse compressor, enabling direct end-of-the-fiber femtosecond...

  16. Fundamentals of electronics

    CERN Document Server

    Schubert, Thomas F

    2015-01-01

    This book, Electronic Devices and Circuit Application, is the first of four books of a larger work, Fundamentals of Electronics. It is comprised of four chapters describing the basic operation of each of the four fundamental building blocks of modern electronics: operational amplifiers, semiconductor diodes, bipolar junction transistors, and field effect transistors. Attention is focused on the reader obtaining a clear understanding of each of the devices when it is operated in equilibrium. Ideas fundamental to the study of electronic circuits are also developed in the book at a basic level to

  17. Polarized Raman scattering study of kesterite type Cu2ZnSnS4 single crystals

    OpenAIRE

    Maxim Guc; Sergiu Levcenko; Ivan V. Bodnar; Victor Izquierdo-Roca; Xavier Fontane; Volkova, Larisa V.; Ernest Arushanov; Alejandro Pérez-Rodríguez

    2016-01-01

    A non-destructive Raman spectroscopy has been widely used as a complimentary method to X-ray diffraction characterization of Cu2ZnSnS4 (CZTS) thin films, yet our knowledge of the Raman active fundamental modes in this material is far from complete. Focusing on polarized Raman spectroscopy provides important information about the relationship between Raman modes and CZTS crystal structure. In this framework the zone–center optical phonons of CZTS, which is most usually examined in active layer...

  18. Fundamentals of electrochemical science

    CERN Document Server

    Oldham, Keith

    1993-01-01

    Key Features* Deals comprehensively with the basic science of electrochemistry* Treats electrochemistry as a discipline in its own right and not as a branch of physical or analytical chemistry* Provides a thorough and quantitative description of electrochemical fundamentals

  19. Fundamentals of crystallography

    CERN Document Server

    2011-01-01

    Crystallography is a basic tool for scientists in many diverse disciplines. This text offers a clear description of fundamentals and of modern applications. It supports curricula in crystallography at undergraduate level.

  20. An Analysis of MT Forward Modeling and Different Polarization Modes in 3D Fault Model%三维断层模型的 MT 正演响应及极化模式分析

    Institute of Scientific and Technical Information of China (English)

    梁霄; 艾林; 吴仁学

    2016-01-01

    从三维断层地质体 MT 的正演响应出发,通过两条测线不同极化模式的对比分析,得出了断层 MT 响应的正演规律:TE 极化模式纵向分辨率比 TM极化模式要高;横向分辨率上 TM极化模式比 TE 极化模式分辨率高,对模型有更高的识别度和灵敏度,能更好地反应断层构造形态上的电阻率差异;通过两条测线的对比分析可判断出断层走向和倾向,对今后 MT 中的断层识别,起到一定的指导作用。%Three-dimensional magnetotelluric sounding positive and negative speech technology is leading edge research in geophysical exploration field.The theoretical research is not deep enough.This study starts from MT forward response about three-dimensional structure of fault,by analyzing the difference between the different polarization modes of two lines.I draw the following conclusions:firstly,TM mode’s transverse resolution has a higher resolution than TE mode,and then I know TMmode is higher than the TE mode in the model identification and sensitivity.We can get the trend and tendency of the faults by comparing the response results of the two lines. These conclusions can play a guiding role in Fault identification in the MT in latterly study.

  1. Fundamentals of structural dynamics

    CERN Document Server

    Craig, Roy R

    2006-01-01

    From theory and fundamentals to the latest advances in computational and experimental modal analysis, this is the definitive, updated reference on structural dynamics.This edition updates Professor Craig's classic introduction to structural dynamics, which has been an invaluable resource for practicing engineers and a textbook for undergraduate and graduate courses in vibrations and/or structural dynamics. Along with comprehensive coverage of structural dynamics fundamentals, finite-element-based computational methods, and dynamic testing methods, this Second Edition includes new and e

  2. Masses of Fundamental Particles

    CERN Document Server

    Terazawa, Hidezumi

    2011-01-01

    Not only the masses of fundamental particles including the weak bosons, Higgs scalar, quarks, and leptons, but also the mixing angles of quarks and those of neutrinos are all explained and/or predicted in the unified composite model of quarks and leptons successfully. In addition, both of the two anomalies recently found by the CDF Collaboration are suggested to be taken as evidences for the substructure of the fundamental particles.

  3. Information security fundamentals

    CERN Document Server

    Peltier, Thomas R

    2013-01-01

    Developing an information security program that adheres to the principle of security as a business enabler must be the first step in an enterprise's effort to build an effective security program. Following in the footsteps of its bestselling predecessor, Information Security Fundamentals, Second Edition provides information security professionals with a clear understanding of the fundamentals of security required to address the range of issues they will experience in the field.The book examines the elements of computer security, employee roles and r

  4. 基于小波降噪的偏振耦合检测分析%Analysis of polarization mode coupling of PMF based on wavelet denoising method

    Institute of Scientific and Technical Information of China (English)

    郭振武; 陈信伟; 张红霞; 贾大功; 刘铁根

    2011-01-01

    理论分析了基于白光干涉的保偏光纤偏振模式耦合检测原理,并以迈克尔逊干涉仪对保偏光纤的偏振耦合的耦合强度和耦合点的位置进行了测试.由于机械式扫描干涉仪和信号处理电路会受到环境干扰和各种噪声的影响,限制了系统偏振耦合检测的灵敏度,应用小波变换对检测信号进行了分析,采用软阈值方法降噪处理,有效地去除了各种干扰和噪声,提高了干涉信号的信噪比3.2dB,耦合强度测试灵敏度也相应地得到了提高,增强了测试系统检测微弱偏振耦合的能力.%The principle of the cross coupling in polarization maintaining fiber based on white-light interferometry is presented The coupling intensity and coupling position are measured by using Michelson-interferometer. The sensitivity of detection system is limited by environmental disturbance and mixture noise in the course of scanning measurement of the mechanical interferometer and signal processing. A wavelet soft threshold denoising method is adopted to process the interference signals. And then the noises are strongly restrained and the signal-to-noise ratio of the output signal is improved about 3. 2 dB. The sensitivity increases correspondingly, and the ability of detecting weak coupling is improved.

  5. Polarizing Filter for Integrated Optics

    Science.gov (United States)

    Ramer, O. G.; Goss, W. C.; Goldstein, R.

    1986-01-01

    Polarizing filter for titanium-doped lithium niobate light waveguide suppresses transverse magnetic (TM) mode of light propagation while allowing transverse electric (TE) mode to continue on its way. Filter - lithium niobate crystal - is expected to find many applications in integrated optical circuits.

  6. Wave modes of collective vortex gyration in dipolar-coupled-dot-array magnonic crystals

    Science.gov (United States)

    Han, Dong-Soo; Vogel, Andreas; Jung, Hyunsung; Lee, Ki-Suk; Weigand, Markus; Stoll, Hermann; Schütz, Gisela; Fischer, Peter; Meier, Guido; Kim, Sang-Koog

    2013-07-01

    Lattice vibration modes are collective excitations in periodic arrays of atoms or molecules. These modes determine novel transport properties in solid crystals. Analogously, in periodical arrangements of magnetic vortex-state disks, collective vortex motions have been predicted. Here, we experimentally observe wave modes of collective vortex gyration in one-dimensional (1D) periodic arrays of magnetic disks using time-resolved scanning transmission x-ray microscopy. The observed modes are interpreted based on micromagnetic simulation and numerical calculation of coupled Thiele equations. Dispersion of the modes is found to be strongly affected by both vortex polarization and chirality ordering, as revealed by the explicit analytical form of 1D infinite arrays. A thorough understanding thereof is fundamental both for lattice vibrations and vortex dynamics, which we demonstrate for 1D magnonic crystals. Such magnetic disk arrays with vortex-state ordering, referred to as magnetic metastructure, offer potential implementation into information processing devices.

  7. Variation of Fundamental Constants

    Science.gov (United States)

    Flambaum, V. V.

    2006-11-01

    Theories unifying gravity with other interactions suggest temporal and spatial variation of the fundamental ``constants'' in expanding Universe. The spatial variation can explain a fine tuning of the fundamental constants which allows humans (and any life) to appear. We appeared in the area of the Universe where the values of the fundamental constants are consistent with our existence. We present a review of recent works devoted to the variation of the fine structure constant α, strong interaction and fundamental masses. There are some hints for the variation in quasar absorption spectra. Big Bang nucleosynthesis, and Oklo natural nuclear reactor data. A very promising method to search for the variation of the fundamental constants consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transition between accidentally degenerate atomic and molecular energy levels. A new idea is to build a ``nuclear'' clock based on the ultraviolet transition between very low excited state and ground state in Thorium nucleus. This may allow to improve sensitivity to the variation up to 10 orders of magnitude! Huge enhancement of the variation effects is also possible in cold atomic and molecular collisions near Feshbach resonance.

  8. Polarization and Polarimetry: A Review

    CERN Document Server

    Trippe, S

    2014-01-01

    Polarization is a basic property of light and is fundamentally linked to the internal geometry of a source of radiation. Polarimetry complements photometric, spectroscopic, and imaging analyses of sources of radiation and has made possible multiple astrophysical discoveries. In this article I review (i) the physical basics of polarization: electromagnetic waves, photons, and parameterizations; (ii) astrophysical sources of polarization: scattering, synchrotron radiation, active media, and the Zeeman, Goldreich-Kylafis, and Hanle effects, as well as interactions between polarization and matter (like birefringence, Faraday rotation, or the Chandrasekhar-Fermi effect); (iii) observational methodology: on-sky geometry, influence of atmosphere and instrumental polarization, polarization statistics, and observational techniques for radio, optical, and X/gamma wavelengths; and (iv) science cases for astronomical polarimetry: solar and stellar physics, planetary system bodies, interstellar matter, astrobiology, astro...

  9. Polarization entangled cluster state generation in a lithium niobate chip

    Science.gov (United States)

    Szep, Attila; Kim, Richard; Shin, Eunsung; Fanto, Michael L.; Osman, Joseph; Alsing, Paul M.

    2016-10-01

    We present a design of a quantum information processing C-phase (Controlled-phase) gate applicable for generating cluster states that has a form of integrated photonic circuits assembled with cascaded directional couplers on a Ti in-diffused Lithium Niobate (Ti-LN) platform where directional couplers as the integrated optical analogue of bulk beam splitters are used as fundamental building blocks. Based on experimentally optimized fabrication parameters of Ti-LN optical waveguides operating at an 810nm wavelength, an integrated Ti-LN quantum C-phase gate is designed and simulated. Our proposed C-phase gate consists of three tunable directional couplers cascaded together with having different weighted switching ratios for providing a tool of routing vertically- and horizontally-polarized photons independently. Its operation mechanism relies on selectively controlling the optical coupling of orthogonally polarized modes via the change in the index of refraction, and its operation is confirmed by the BPM simulation.

  10. Partial Polarization in Interfered Plasmon Fields

    Directory of Open Access Journals (Sweden)

    P. Martínez Vara

    2014-01-01

    Full Text Available We describe the polarization features for plasmon fields generated by the interference between two elemental surface plasmon modes, obtaining a set of Stokes parameters which allows establishing a parallelism with the traditional polarization model. With the analysis presented, we find the corresponding coherence matrix for plasmon fields incorporating to the plasmon optics the study of partial polarization effects.

  11. Primordial magnetism in CMB polarization

    Science.gov (United States)

    Pogosian, Levon

    2014-03-01

    A large scale B-mode signal in the CMB polarization would constitute a smoking gun of Inflation and is the main target of several ongoing and upcoming experiments. In this contribution, I consider distinguishing features of another potential source of primordial B-modes - magnetic fields. In particular, the Faraday Rotation of CMB polarization provides a distinctive signature of cosmic magnetic fields through the characteristic frequency dependence and the mode-coupling correlations of the CMB variables. I discuss constraints on primordial magnetism that can be expected from future CMB experiments, taking into account the obstruction caused by the magnetic field of the Milky Way.

  12. Fundamentals of algebraic topology

    CERN Document Server

    Weintraub, Steven H

    2014-01-01

    This rapid and concise presentation of the essential ideas and results of algebraic topology follows the axiomatic foundations pioneered by Eilenberg and Steenrod. The approach of the book is pragmatic: while most proofs are given, those that are particularly long or technical are omitted, and results are stated in a form that emphasizes practical use over maximal generality. Moreover, to better reveal the logical structure of the subject, the separate roles of algebra and topology are illuminated. Assuming a background in point-set topology, Fundamentals of Algebraic Topology covers the canon of a first-year graduate course in algebraic topology: the fundamental group and covering spaces, homology and cohomology, CW complexes and manifolds, and a short introduction to homotopy theory. Readers wishing to deepen their knowledge of algebraic topology beyond the fundamentals are guided by a short but carefully annotated bibliography.

  13. Fundamentals of turbomachines

    CERN Document Server

    Dick, Erik

    2015-01-01

    This book explores the working principles of all kinds of turbomachines. The same theoretical framework is used to analyse the different machine types. Fundamentals are first presented and theoretical concepts are then elaborated for particular machine types, starting with the simplest ones.For each machine type, the author strikes a balance between building basic understanding and exploring knowledge of practical aspects. Readers are invited through challenging exercises to consider how the theory applies to particular cases and how it can be generalised.   The book is primarily meant as a course book. It teaches fundamentals and explores applications. It will appeal to senior undergraduate and graduate students in mechanical engineering and to professional engineers seeking to understand the operation of turbomachines. Readers will gain a fundamental understanding of turbomachines. They will also be able to make a reasoned choice of turbomachine for a particular application and to understand its operation...

  14. Monte Carlo fundamentals

    Energy Technology Data Exchange (ETDEWEB)

    Brown, F.B.; Sutton, T.M.

    1996-02-01

    This report is composed of the lecture notes from the first half of a 32-hour graduate-level course on Monte Carlo methods offered at KAPL. These notes, prepared by two of the principle developers of KAPL`s RACER Monte Carlo code, cover the fundamental theory, concepts, and practices for Monte Carlo analysis. In particular, a thorough grounding in the basic fundamentals of Monte Carlo methods is presented, including random number generation, random sampling, the Monte Carlo approach to solving transport problems, computational geometry, collision physics, tallies, and eigenvalue calculations. Furthermore, modern computational algorithms for vector and parallel approaches to Monte Carlo calculations are covered in detail, including fundamental parallel and vector concepts, the event-based algorithm, master/slave schemes, parallel scaling laws, and portability issues.

  15. Quantum theory and experimental study of laser polarization

    Energy Technology Data Exchange (ETDEWEB)

    Guo Siji; Gao Zhihui; Mao Huajin

    1987-02-01

    The full quantum theory of laser polarization is presented in this paper. The polarization properties of multimode laser beam in anisotropic cavity are analysed. Basic equations, calculation curve and polarization configurations of describing the inter-angle of mode polarization directions in 6328 A He-Ne laser vs. anisotropy are given. The effects of the phase anisotropy on mode polarization by stress is investigated. The experimental result and theory analysis is coincident.

  16. Assignment of the Fundamental Modes of Hydroxyacetone Using Gas-Phase Infrared, Far-Infrared, Raman, and ab Initio Methods: Band Strengths for Atmospheric Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lindenmaier, Rodica; Tipton, Nicole; Sams, Robert L.; Brauer, Carolyn S.; Blake, Thomas A.; Williams, Stephen D.; Johnson, Timothy J.

    2016-08-04

    Hydroxyacetone (acetol) is a simple organic molecule of interest in both the astrophysical and atmospheric communities, having recently been observed in biomass burning events, as well as a known degradation product of isoprene oxidation. However, its vibrational assignment has never been fully completed, and few quantitative data are available for its detection via infrared spectroscopy. Our recent acquisition of both the pressure-broadened gas-phase data and the far-IR spectra now allow for unambiguous assignment of several (new) bands. In particular, the observed C-type bands of several fundamentals (particularly in the far-infrared) and a few combination bands demonstrate that the monomer is in a planar (Cs) conformation, at least a majority of the time. As suggested by other researchers, the monomer is a cis-cis conformer stabilized by an intramolecular O—H···O=C hydrogen bond forming a five-membered planar ring structure. Band assignments in the Cs point group are justified (at least for a good fraction of the molecules in the ensemble) by the presence of the C-type bands. The results and band assignments are well confirmed by both ab initio MP2-ccpvtz calculations as well as GAMESS (B3LYP) theoretical calculations. In addition, using vetted methods for quantitative measurements, we report the first IR absorption band strengths of acetol (also in electronic format) that can be used for atmospheric monitoring and other applications.

  17. Fundamentals of fluid lubrication

    Science.gov (United States)

    Hamrock, Bernard J.

    1991-01-01

    The aim is to coordinate the topics of design, engineering dynamics, and fluid dynamics in order to aid researchers in the area of fluid film lubrication. The lubrication principles that are covered can serve as a basis for the engineering design of machine elements. The fundamentals of fluid film lubrication are presented clearly so that students that use the book will have confidence in their ability to apply these principles to a wide range of lubrication situations. Some guidance on applying these fundamentals to the solution of engineering problems is also provided.

  18. Infosec management fundamentals

    CERN Document Server

    Dalziel, Henry

    2015-01-01

    Infosec Management Fundamentals is a concise overview of the Information Security management concepts and techniques, providing a foundational template for both experienced professionals and those new to the industry. This brief volume will also appeal to business executives and managers outside of infosec who want to understand the fundamental concepts of Information Security and how it impacts their business decisions and daily activities. Teaches ISO/IEC 27000 best practices on information security management Discusses risks and controls within the context of an overall information securi

  19. Fundamentals of piping design

    CERN Document Server

    Smith, Peter

    2013-01-01

    Written for the piping engineer and designer in the field, this two-part series helps to fill a void in piping literature,since the Rip Weaver books of the '90s were taken out of print at the advent of the Computer Aid Design(CAD) era. Technology may have changed, however the fundamentals of piping rules still apply in the digitalrepresentation of process piping systems. The Fundamentals of Piping Design is an introduction to the designof piping systems, various processes and the layout of pipe work connecting the major items of equipment forthe new hire, the engineering student and the vetera

  20. Homeschooling and religious fundamentalism

    Directory of Open Access Journals (Sweden)

    Robert KUNZMAN

    2010-10-01

    Full Text Available This article considers the relationship between homeschooling and religious fundamentalism by focusing on their intersection in the philosophies and practices of conservative Christian homeschoolers in the United States. Homeschooling provides an ideal educational setting to support several core fundamentalist principles: resistance to contemporary culture; suspicion of institutional authority and professional expertise; parental control and centrality of the family; and interweaving of faith and academics. It is important to recognize, however, that fundamentalism exists on a continuum; conservative religious homeschoolers resist liberal democratic values to varying degrees, and efforts to foster dialogue and accommodation with religious homeschoolers can ultimately helpstrengthen the broader civic fabric.

  1. Pragmatic electrical engineering fundamentals

    CERN Document Server

    Eccles, William

    2011-01-01

    Pragmatic Electrical Engineering: Fundamentals introduces the fundamentals of the energy-delivery part of electrical systems. It begins with a study of basic electrical circuits and then focuses on electrical power. Three-phase power systems, transformers, induction motors, and magnetics are the major topics.All of the material in the text is illustrated with completely-worked examples to guide the student to a better understanding of the topics. This short lecture book will be of use at any level of engineering, not just electrical. Its goal is to provide the practicing engineer with a practi

  2. Fundamentals of nonlinear optics

    CERN Document Server

    Powers, Peter E

    2011-01-01

    Peter Powers's rigorous but simple description of a difficult field keeps the reader's attention throughout. … All chapters contain a list of references and large numbers of practice examples to be worked through. … By carefully working through the proposed problems, students will develop a sound understanding of the fundamental principles and applications. … the book serves perfectly for an introductory-level course for second- and third-order nonlinear optical phenomena. The author's writing style is refreshing and original. I expect that Fundamentals of Nonlinear Optics will fast become pop

  3. Fundamentals of continuum mechanics

    CERN Document Server

    Rudnicki, John W

    2014-01-01

    A concise introductory course text on continuum mechanics Fundamentals of Continuum Mechanics focuses on the fundamentals of the subject and provides the background for formulation of numerical methods for large deformations and a wide range of material behaviours. It aims to provide the foundations for further study, not just of these subjects, but also the formulations for much more complex material behaviour and their implementation computationally.  This book is divided into 5 parts, covering mathematical preliminaries, stress, motion and deformation, balance of mass, momentum and energ

  4. Antennas fundamentals, design, measurement

    CERN Document Server

    Long, Maurice

    2009-01-01

    This comprehensive revision (3rd Edition) is a senior undergraduate or first-year graduate level textbook on antenna fundamentals, design, performance analysis, and measurements. In addition to its use as a formal course textbook, the book's pragmatic style and emphasis on the fundamentals make it especially useful to engineering professionals who need to grasp the essence of the subject quickly but without being mired in unnecessary detail. This new edition was prepared for a first year graduate course at Southern Polytechnic State University in Georgia. It provides broad coverage of antenna

  5. Fundamentals of magnetism

    CERN Document Server

    Reis, Mario

    2013-01-01

    The Fundamentals of Magnetism is a truly unique reference text, that explores the study of magnetism and magnetic behavior with a depth that no other book can provide. It covers the most detailed descriptions of the fundamentals of magnetism providing an emphasis on statistical mechanics which is absolutely critical for understanding magnetic behavior. The books covers the classical areas of basic magnetism, including Landau Theory and magnetic interactions, but features a more concise and easy-to-read style. Perfect for upper-level graduate students and industry researchers, The Fu

  6. Polarization Dependence of Linewidth Enhancement Factor in Semiconductor Optical Amplifier and Its Implication for Nonlinear Polarization Rotation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Shuang; WU Chong-Qing; WANG Yong-Jun

    2009-01-01

    Linewidth enhancement factors (LEFs) of the transverse electric mode and the transverse magnetic mode in bulk semiconductor optical amplifiers are measured using the nonlinear optical loop mirror method and the principal state of polarization vector method.The polarization dependence of LEFs plays an important role in the nonlinear polarization rotation.The relationship between the polarization-dependence of LEFs and nonlinear polarization rotation in the Stokes space is demonstrated.

  7. Homeschooling and Religious Fundamentalism

    Science.gov (United States)

    Kunzman, Robert

    2010-01-01

    This article considers the relationship between homeschooling and religious fundamentalism by focusing on their intersection in the philosophies and practices of conservative Christian homeschoolers in the United States. Homeschooling provides an ideal educational setting to support several core fundamentalist principles: resistance to…

  8. Fundamental partial compositeness

    DEFF Research Database (Denmark)

    Sannino, Francesco; Strumia, Alessandro; Tesi, Andrea

    2016-01-01

    We construct renormalizable Standard Model extensions, valid up to the Planck scale, that give a composite Higgs from a new fundamental strong force acting on fermions and scalars. Yukawa interactions of these particles with Standard Model fermions realize the partial compositeness scenario. Unde...

  9. Fundamentals of Business Economics

    OpenAIRE

    2013-01-01

    Powerpoint presentations of the 9 theoretical units of the subject: Fundamentals of Business Economics. Business Administration Degree. Faculty of Economics. University of Alicante En el marco de ayudas a preparación de materiales docentes en lengua inglesa, por parte del Servei de Política Llingüística de la Universidad de Alicante

  10. Fundamental Physics Microgravity Sensitivity

    Science.gov (United States)

    Israelsson, Ulf

    1998-01-01

    An introduction followed by a brief discussion about the sensitivity to microgravity environment disturbances for some recent and planned experiments in microgravity fundamental physics will be presented. In particular, correlation between gravity disturbances and the quality of science data sets measured by the Confined Helium Experiment (CHEX) during ground testing and during the November 1997 USMP-4 flight will be described.

  11. Fundamental Metallurgy of Solidification

    DEFF Research Database (Denmark)

    Tiedje, Niels

    2004-01-01

    The text takes the reader through some fundamental aspects of solidification, with focus on understanding the basic physics that govern solidification in casting and welding. It is described how the first solid is formed and which factors affect nucleation. It is described how crystals grow from ...

  12. Fundamentals of convolutional coding

    CERN Document Server

    Johannesson, Rolf

    2015-01-01

    Fundamentals of Convolutional Coding, Second Edition, regarded as a bible of convolutional coding brings you a clear and comprehensive discussion of the basic principles of this field * Two new chapters on low-density parity-check (LDPC) convolutional codes and iterative coding * Viterbi, BCJR, BEAST, list, and sequential decoding of convolutional codes * Distance properties of convolutional codes * Includes a downloadable solutions manual

  13. Fundamentals of soil science

    Science.gov (United States)

    This study guide provides comments and references for professional soil scientists who are studying for the soil science fundamentals exam needed as the first step for certification. The performance objectives were determined by the Soil Science Society of America's Council of Soil Science Examiners...

  14. Fundamentals and Optimal Institutions

    DEFF Research Database (Denmark)

    Gonzalez-Eiras, Martin; Harmon, Nikolaj Arpe; Rossi, Martín

    2016-01-01

    of regulatory institutions such as revenue sharing, salary caps or luxury taxes. We show, theoretically and empirically, that these large differences in adopted institutions can be rationalized as optimal responses to differences in the fundamental characteristics of the sports being played. This provides...

  15. Fundamentals of astrodynamics

    NARCIS (Netherlands)

    Wakker, K.F.

    2015-01-01

    This book deals with the motion of the center of mass of a spacecraft; this discipline is generally called astrodynamics. The book focuses on an analytical treatment of the motion of spacecraft and provides insight into the fundamentals of spacecraft orbit dynamics. A large number of topics are trea

  16. Fundamentals of plasma physics

    CERN Document Server

    Bittencourt, J A

    1986-01-01

    A general introduction designed to present a comprehensive, logical and unified treatment of the fundamentals of plasma physics based on statistical kinetic theory. Its clarity and completeness make it suitable for self-learning and self-paced courses. Problems are included.

  17. Nanowire Plasmon Excitation by Adiabatic Mode Transformation

    Science.gov (United States)

    Verhagen, Ewold; Spasenović, Marko; Polman, Albert; Kuipers, L. (Kobus)

    2009-05-01

    We show with both experiment and calculation that highly confined surface plasmon polaritons can be efficiently excited on metallic nanowires through the process of mode transformation. One specific mode in a metallic waveguide is identified that adiabatically transforms to the confined nanowire mode as the waveguide width is reduced. Phase- and polarization-sensitive near-field investigation reveals the characteristic antisymmetric polarization nature of the mode and explains the coupling mechanism.

  18. Ultracompact and high efficient silicon-based polarization splitter-rotator using a partially-etched subwavelength grating coupler

    Science.gov (United States)

    Xu, Yin; Xiao, Jinbiao

    2016-06-01

    On-chip polarization manipulation is pivotal for silicon-on-insulator material platform to realize polarization-transparent circuits and polarization-division-multiplexing transmissions, where polarization splitters and rotators are fundamental components. In this work, we propose an ultracompact and high efficient silicon-based polarization splitter-rotator (PSR) using a partially-etched subwavelength grating (SWG) coupler. The proposed PSR consists of a taper-integrated SWG coupler combined with a partially-etched waveguide between the input and output strip waveguides to make the input transverse-electric (TE) mode couple and convert to the output transverse-magnetic (TM) mode at the cross port while the input TM mode confine well in the strip waveguide during propagation and directly output from the bar port with nearly neglected coupling. Moreover, to better separate input polarizations, an additional tapered waveguide extended from the partially-etched waveguide is also added. From results, an ultracompact PSR of only 8.2 μm in length is achieved, which is so far the reported shortest one. The polarization conversion loss and efficiency are 0.12 dB and 98.52%, respectively, together with the crosstalk and reflection loss of -31.41/-22.43 dB and -34.74/-33.13 dB for input TE/TM mode at wavelength of 1.55 μm. These attributes make the present device suitable for constructing on-chip compact photonic integrated circuits with polarization-independence.

  19. Polarized proton beams since the ZGS

    Energy Technology Data Exchange (ETDEWEB)

    Krisch, A.D.

    1994-12-31

    The author discusses research involving polarized proton beams since the ZGS`s demise. He begins by reminding the attendee that in 1973 the ZGS accelerated the world`s first high energy polarized proton beam; all in attendance at this meeting can be proud of this accomplishment. A few ZGS polarized proton beam experiments were done in the early 1970`s; then from about 1976 until 1 October 1979, the majority of the ZGS running time was polarized running. A great deal of fundamental physics was done with the polarized beam when the ZGS ran as a dedicated polarized proton beam from about Fall 1977 until it shut down on 1 October 1979. The newly created polarization enthusiats then dispersed; some spread polarized seeds al over the world by polarizing beams elsewhere; some wound up running the High Energy and SSC programs at DOE.

  20. RECOVERY OF LARGE ANGULAR SCALE CMB POLARIZATION FOR INSTRUMENTS EMPLOYING VARIABLE-DELAY POLARIZATION MODULATORS

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N. J.; Marriage, T. A.; Appel, J. W.; Bennett, C. L.; Eimer, J.; Essinger-Hileman, T.; Harrington, K.; Rostem, K.; Watts, D. J. [Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218 (United States); Chuss, D. T. [Department of Physics, Villanova University, 800 E Lancaster, Villanova, PA 19085 (United States); Wollack, E. J.; Fixsen, D. J.; Moseley, S. H.; Switzer, E. R., E-mail: Nathan.J.Miller@nasa.gov [Observational Cosmology Laboratory, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2016-02-20

    Variable-delay Polarization Modulators (VPMs) are currently being implemented in experiments designed to measure the polarization of the cosmic microwave background on large angular scales because of their capability for providing rapid, front-end polarization modulation and control over systematic errors. Despite the advantages provided by the VPM, it is important to identify and mitigate any time-varying effects that leak into the synchronously modulated component of the signal. In this paper, the effect of emission from a 300 K VPM on the system performance is considered and addressed. Though instrument design can greatly reduce the influence of modulated VPM emission, some residual modulated signal is expected. VPM emission is treated in the presence of rotational misalignments and temperature variation. Simulations of time-ordered data are used to evaluate the effect of these residual errors on the power spectrum. The analysis and modeling in this paper guides experimentalists on the critical aspects of observations using VPMs as front-end modulators. By implementing the characterizations and controls as described, front-end VPM modulation can be very powerful for mitigating 1/f noise in large angular scale polarimetric surveys. None of the systematic errors studied fundamentally limit the detection and characterization of B-modes on large scales for a tensor-to-scalar ratio of r = 0.01. Indeed, r < 0.01 is achievable with commensurately improved characterizations and controls.

  1. Switching Time of Magnetic Moment Driven by Circularly Polarized Field

    Directory of Open Access Journals (Sweden)

    A.Yu. Polyakov

    2012-10-01

    Full Text Available The magnetization switching effect of the uniaxial nanoparticle driven by a circularly polarized in the plane perpendicular to the easy axis field in the presence of thermal fluctuations is studied. The frequency dependence of the magnetic moment switching time from one equilibrium state to another is investigated in details, indicating its resonant character and fundamental dependence on the direction of rotation of the field. The effect of precession mode on switching time is discussed. A comparative analysis of the switching time with a lifetime for precession modes is done in this paper. We study the influence of the damping parameter and the amplitude of the external field on the switching time.

  2. Metal-ion effects on the polarization of metal-bound water and infrared vibrational modes of the coordinated metal center of Mycobacterium tuberculosis pyrazinamidase via quantum mechanical calculations.

    Science.gov (United States)

    Salazar-Salinas, Karim; Baldera-Aguayo, Pedro A; Encomendero-Risco, Jimy J; Orihuela, Melvin; Sheen, Patricia; Seminario, Jorge M; Zimic, Mirko

    2014-08-28

    Mycobacterium tuberculosis pyrazinamidase (PZAse) is a key enzyme to activate the pro-drug pyrazinamide (PZA). PZAse is a metalloenzyme that coordinates in vitro different divalent metal cofactors in the metal coordination site (MCS). Several metals including Co(2+), Mn(2+), and Zn(2+) are able to reactivate the metal-depleted PZAse in vitro. We use quantum mechanical calculations to investigate the Zn(2+), Fe(2+), and Mn(2+) metal cofactor effects on the local MCS structure, metal-ligand or metal-residue binding energy, and charge distribution. Results suggest that the major metal-dependent changes occur in the metal-ligand binding energy and charge distribution. Zn(2+) shows the highest binding energy to the ligands (residues). In addition, Zn(2+) and Mn(2+) within the PZAse MCS highly polarize the O-H bond of coordinated water molecules in comparison with Fe(2+). This suggests that the coordination of Zn(2+) or Mn(2+) to the PZAse protein facilitates the deprotonation of coordinated water to generate a nucleophile for catalysis as in carboxypeptidase A. Because metal ion binding is relevant to enzymatic reaction, identification of the metal binding event is important. The infrared vibrational mode shift of the C═Nε (His) bond from the M. tuberculosis MCS is the best IR probe to metal complexation.

  3. Polarization developments

    Energy Technology Data Exchange (ETDEWEB)

    Prescott, C.Y.

    1993-07-01

    Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist.

  4. Single-mode optical fibres

    CERN Document Server

    Cancellieri, G

    1991-01-01

    This book describes signal propagation in single-mode optical fibres for telecommunication applications. Such description is based on the analysis of field propagation, considering waveguide properties and also some of the particular characteristics of the material fibre. The book covers such recent advances as, coherent transmissions; optical amplification; MIR fibres; polarization maintaining; polarization diversity and photon counting.

  5. Fundamental stellar parameters

    CERN Document Server

    Wittkowski, M

    2004-01-01

    I present a discussion of fundamental stellar parameters and their observational determination in the context of interferometric measurements with current and future optical/infrared interferometric facilities. Stellar parameters and the importance of their determination for stellar physics are discussed. One of the primary uses of interferometry in the field of stellar physics is the measurement of the intensity profile across the stellar disk, both as a function of position angle and of wavelength. High-precision fundamental stellar parameters are also derived by characterizations of binary and multiple system using interferometric observations. This topic is discussed in detail elsewhere in these proceedings. Comparison of observed spectrally dispersed center-to-limb intensity variations with models of stellar atmospheres and stellar evolution may result in an improved understanding of key phenomena in stellar astrophysics such as the precise evolutionary effects on the main sequence, the evolution of meta...

  6. Fundamentals of nuclear physics

    CERN Document Server

    Takigawa, Noboru

    2017-01-01

    This book introduces the current understanding of the fundamentals of nuclear physics by referring to key experimental data and by providing a theoretical understanding of principal nuclear properties. It primarily covers the structure of nuclei at low excitation in detail. It also examines nuclear forces and decay properties. In addition to fundamentals, the book treats several new research areas such as non-relativistic as well as relativistic Hartree–Fock calculations, the synthesis of super-heavy elements, the quantum chromodynamics phase diagram, and nucleosynthesis in stars, to convey to readers the flavor of current research frontiers in nuclear physics. The authors explain semi-classical arguments and derivation of its formulae. In these ways an intuitive understanding of complex nuclear phenomena is provided. The book is aimed at graduate school students as well as junior and senior undergraduate students and postdoctoral fellows. It is also useful for researchers to update their knowledge of diver...

  7. Fundamentals of differential beamforming

    CERN Document Server

    Benesty, Jacob; Pan, Chao

    2016-01-01

    This book provides a systematic study of the fundamental theory and methods of beamforming with differential microphone arrays (DMAs), or differential beamforming in short. It begins with a brief overview of differential beamforming and some popularly used DMA beampatterns such as the dipole, cardioid, hypercardioid, and supercardioid, before providing essential background knowledge on orthogonal functions and orthogonal polynomials, which form the basis of differential beamforming. From a physical perspective, a DMA of a given order is defined as an array that measures the differential acoustic pressure field of that order; such an array has a beampattern in the form of a polynomial whose degree is equal to the DMA order. Therefore, the fundamental and core problem of differential beamforming boils down to the design of beampatterns with orthogonal polynomials. But certain constraints also have to be considered so that the resulting beamformer does not seriously amplify the sensors’ self noise and the mism...

  8. What is Fundamental?

    CERN Multimedia

    2004-01-01

    Discussing what is fundamental in a variety of fields, biologist Richard Dawkins, physicist Gerardus 't Hooft, and mathematician Alain Connes spoke to a packed Main Auditorium at CERN 15 October. Dawkins, Professor of the Public Understanding of Science at Oxford University, explained simply the logic behind Darwinian natural selection, and how it would seem to apply anywhere in the universe that had the right conditions. 't Hooft, winner of the 1999 Physics Nobel Prize, outlined some of the main problems in physics today, and said he thinks physics is so fundamental that even alien scientists from another planet would likely come up with the same basic principles, such as relativity and quantum mechanics. Connes, winner of the 1982 Fields Medal (often called the Nobel Prize of Mathematics), explained how physics is different from mathematics, which he described as a "factory for concepts," unfettered by connection to the physical world. On 16 October, anthropologist Sharon Traweek shared anecdotes from her ...

  9. Variation of fundamental constants

    CERN Document Server

    Flambaum, V V

    2006-01-01

    We present a review of recent works devoted to the variation of the fine structure constant alpha, strong interaction and fundamental masses. There are some hints for the variation in quasar absorption spectra, Big Bang nucleosynthesis, and Oklo natural nuclear reactor data. A very promising method to search for the variation of the fundamental constants consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transition between accidentally degenerate atomic and molecular energy levels. A new idea is to build a ``nuclear'' clock based on the ultraviolet transition between very low excited state and ground state in Thorium nucleus. This may allow to improve sensitivity to the variation up to 10 orders of magnitude! Huge enhancement of the variation effects is also possible in cold atomic and molecular collisions near Feschbach resonance.

  10. Fundamental composite electroweak dynamics

    DEFF Research Database (Denmark)

    Arbey, Alexandre; Cacciapaglia, Giacomo; Cai, Haiying

    2017-01-01

    Using the recent joint results from the ATLAS and CMS collaborations on the Higgs boson, we determine the current status of composite electroweak dynamics models based on the expected scalar sector. Our analysis can be used as a minimal template for a wider class of models between the two limiting...... cases of composite Goldstone Higgs and Technicolor-like ones. This is possible due to the existence of a unified description, both at the effective and fundamental Lagrangian levels, of models of composite Higgs dynamics where the Higgs boson itself can emerge, depending on the way the electroweak...... space at the effective Lagrangian level. We show that a wide class of models of fundamental composite electroweak dynamics are still compatible with the present constraints. The results are relevant for the ongoing and future searches at the Large Hadron Collider....

  11. Fundamentals of Stochastic Networks

    CERN Document Server

    Ibe, Oliver C

    2011-01-01

    An interdisciplinary approach to understanding queueing and graphical networks In today's era of interdisciplinary studies and research activities, network models are becoming increasingly important in various areas where they have not regularly been used. Combining techniques from stochastic processes and graph theory to analyze the behavior of networks, Fundamentals of Stochastic Networks provides an interdisciplinary approach by including practical applications of these stochastic networks in various fields of study, from engineering and operations management to communications and the physi

  12. Fundamentals of queueing theory

    CERN Document Server

    Gross, Donald; Thompson, James M; Harris, Carl M

    2013-01-01

    Praise for the Third Edition ""This is one of the best books available. Its excellent organizational structure allows quick reference to specific models and its clear presentation . . . solidifies the understanding of the concepts being presented.""-IIE Transactions on Operations Engineering Thoroughly revised and expanded to reflect the latest developments in the field, Fundamentals of Queueing Theory, Fourth Edition continues to present the basic statistical principles that are necessary to analyze the probabilistic nature of queues. Rather than pre

  13. Fundamentals of Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Wollaber, Allan Benton [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-16

    This is a powerpoint presentation which serves as lecture material for the Parallel Computing summer school. It goes over the fundamentals of the Monte Carlo calculation method. The material is presented according to the following outline: Introduction (background, a simple example: estimating π), Why does this even work? (The Law of Large Numbers, The Central Limit Theorem), How to sample (inverse transform sampling, rejection), and An example from particle transport.

  14. High voltage engineering fundamentals

    CERN Document Server

    Kuffel, E; Hammond, P

    1984-01-01

    Provides a comprehensive treatment of high voltage engineering fundamentals at the introductory and intermediate levels. It covers: techniques used for generation and measurement of high direct, alternating and surge voltages for general application in industrial testing and selected special examples found in basic research; analytical and numerical calculation of electrostatic fields in simple practical insulation system; basic ionisation and decay processes in gases and breakdown mechanisms of gaseous, liquid and solid dielectrics; partial discharges and modern discharge detectors; and over

  15. Biomedical engineering fundamentals

    CERN Document Server

    Bronzino, Joseph D

    2014-01-01

    Known as the bible of biomedical engineering, The Biomedical Engineering Handbook, Fourth Edition, sets the standard against which all other references of this nature are measured. As such, it has served as a major resource for both skilled professionals and novices to biomedical engineering.Biomedical Engineering Fundamentals, the first volume of the handbook, presents material from respected scientists with diverse backgrounds in physiological systems, biomechanics, biomaterials, bioelectric phenomena, and neuroengineering. More than three dozen specific topics are examined, including cardia

  16. Fundamentals of neurobiology.

    Science.gov (United States)

    Greg Hall, D

    2011-01-01

    Session 1 of the 2010 STP/IFSTP Joint Symposium on Toxicologic Neuropathology, titled "Fundamentals of Neurobiology," was organized to provide a foundation for subsequent sessions by presenting essential elements of neuroanatomy and nervous system function. A brief introduction to the session titled "Introduction to Correlative Neurobiology" was provided by Dr. Greg Hall (Eli Lilly and Company, Indianapolis, IN). Correlative neurobiology refers to considerations of the relationships between the highly organized and compartmentalized structure of nervous tissues and the functioning within this system.

  17. Fundamentals of Biomechanics

    OpenAIRE

    Duane Knudson

    2007-01-01

    DESCRIPTION This book provides a broad and in-depth theoretical and practical description of the fundamental concepts in understanding biomechanics in the qualitative analysis of human movement. PURPOSE The aim is to bring together up-to-date biomechanical knowledge with expert application knowledge. Extensive referencing for students is also provided. FEATURES This textbook is divided into 12 chapters within four parts, including a lab activities section at the end. The division is as follow...

  18. Fundamentals of linear algebra

    CERN Document Server

    Dash, Rajani Ballav

    2008-01-01

    FUNDAMENTALS OF LINEAR ALGEBRA is a comprehensive Text Book, which can be used by students and teachers of All Indian Universities. The Text has easy, understandable form and covers all topics of UGC Curriculum. There are lots of worked out examples which helps the students in solving the problems without anybody's help. The Problem sets have been designed keeping in view of the questions asked in different examinations.

  19. Neutrons and Fundamental Symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Plaster, Bradley [Univ. of Kentucky, Lexington, KY (United States). Dept. of Physics and Astronomy

    2016-01-11

    The research supported by this project addressed fundamental open physics questions via experiments with subatomic particles. In particular, neutrons constitute an especially ideal “laboratory” for fundamental physics tests, as their sensitivities to the four known forces of nature permit a broad range of tests of the so-called “Standard Model”, our current best physics model for the interactions of subatomic particles. Although the Standard Model has been a triumphant success for physics, it does not provide satisfactory answers to some of the most fundamental open questions in physics, such as: are there additional forces of nature beyond the gravitational, electromagnetic, weak nuclear, and strong nuclear forces?, or why does our universe consist of more matter than anti-matter? This project also contributed significantly to the training of the next generation of scientists, of considerable value to the public. Young scientists, ranging from undergraduate students to graduate students to post-doctoral researchers, made significant contributions to the work carried out under this project.

  20. Value of Fundamental Science

    Science.gov (United States)

    Burov, Alexey

    Fundamental science is a hard, long-term human adventure that has required high devotion and social support, especially significant in our epoch of Mega-science. The measure of this devotion and this support expresses the real value of the fundamental science in public opinion. Why does fundamental science have value? What determines its strength and what endangers it? The dominant answer is that the value of science arises out of curiosity and is supported by the technological progress. Is this really a good, astute answer? When trying to attract public support, we talk about the ``mystery of the universe''. Why do these words sound so attractive? What is implied by and what is incompatible with them? More than two centuries ago, Immanuel Kant asserted an inseparable entanglement between ethics and metaphysics. Thus, we may ask: which metaphysics supports the value of scientific cognition, and which does not? Should we continue to neglect the dependence of value of pure science on metaphysics? If not, how can this issue be addressed in the public outreach? Is the public alienated by one or another message coming from the face of science? What does it mean to be politically correct in this sort of discussion?

  1. Higher Order Mode Fibers

    DEFF Research Database (Denmark)

    Israelsen, Stine Møller

    . The research presented in this thesis falls in three parts. In the first part, a first time demonstration of the break of the azimuthal symmetry of the Bessel-like LP0X modes is presented. This effect, known as the bowtie effect, causes the mode to have an azimuthal dependence as well as a quasi...... and polarization state are investigated. For this fiber, the onset of the bowtie effect is shown numerically to be LP011. The characteristics usually associated with Bessel-likes modes such as long diffraction free length and selfhealing are shown to be conserved despite the lack of azimuthal symmetry...

  2. Dynamics on the SU(2) fundamental domain

    CERN Document Server

    Van den Heuvel, B; van den Heuvel, Bas; van Baal, Pierre

    1994-01-01

    For SU(2) gauge theory on the three-sphere we focus on a subspace of modes of the gauge field that contains the tunnelling paths and the sphalerons and on which the energy functional is degenerate to second order in the fields. The ultimate goal is to study the \\theta-dependence of the low-lying states for this model by imposing boundary conditions on the fundamental domain.

  3. PEM Fuel Cells - Fundamentals, Modeling and Applications

    Directory of Open Access Journals (Sweden)

    Maher A.R. Sadiq Al-Baghdadi

    2013-01-01

    Full Text Available Part I: Fundamentals Chapter 1: Introduction. Chapter 2: PEM fuel cell thermodynamics, electrochemistry, and performance. Chapter 3: PEM fuel cell components. Chapter 4: PEM fuel cell failure modes. Part II: Modeling and Simulation Chapter 5: PEM fuel cell models based on semi-empirical simulation. Chapter 6: PEM fuel cell models based on computational fluid dynamics. Part III: Applications Chapter 7: PEM fuel cell system design and applications.

  4. Polarization, political

    NARCIS (Netherlands)

    M. Wojcieszak

    2015-01-01

    Polarization has been studied in three different forms: on a social, group, and individual level. This entry first focuses on the undisputed phenomenon of elite polarization (i.e., increasing adherence of policy positions among the elites) and also outlines different approaches to assessing mass pol

  5. Polar Codes

    Science.gov (United States)

    2014-12-01

    QPSK Gaussian channels . .......................................................................... 39 vi 1. INTRODUCTION Forward error correction (FEC...Capacity of BSC. 7 Figure 5. Capacity of AWGN channel . 8 4. INTRODUCTION TO POLAR CODES Polar codes were introduced by E. Arikan in [1]. This paper...Under authority of C. A. Wilgenbusch, Head ISR Division EXECUTIVE SUMMARY This report describes the results of the project “More reliable wireless

  6. Polarization holography

    DEFF Research Database (Denmark)

    Nikolova, L.; Ramanujam, P.S.

    Current research into holography is concerned with applications in optically storing, retrieving, and processing information. Polarization holography has many unique properties compared to conventional holography. It gives results in high efficiency, achromaticity, and special polarization...... properties. This books reviews the research carried out in this field over the last 15 years. The authors provide basic concepts in polarization and the propagation of light through anisotropic materials, before presenting a sound theoretical basis for polarization holography. The fabrication...... and characterization of azobenzene based materials, which remain the most efficient for the purpose, is described in detail. This is followed by a description of other materials that are used in polarization holography. An in-depth description of various applications, including display holography and optical storage...

  7. Polarization holography

    DEFF Research Database (Denmark)

    Nikolova, L.; Ramanujam, P.S.

    properties. This books reviews the research carried out in this field over the last 15 years. The authors provide basic concepts in polarization and the propagation of light through anisotropic materials, before presenting a sound theoretical basis for polarization holography. The fabrication......Current research into holography is concerned with applications in optically storing, retrieving, and processing information. Polarization holography has many unique properties compared to conventional holography. It gives results in high efficiency, achromaticity, and special polarization...... and characterization of azobenzene based materials, which remain the most efficient for the purpose, is described in detail. This is followed by a description of other materials that are used in polarization holography. An in-depth description of various applications, including display holography and optical storage...

  8. Polarization-dependent intermodal four-wave mixing in a birefringent multimode photonic crystal fiber.

    Science.gov (United States)

    Yuan, Jinhui; Kang, Zhe; Li, Feng; Zhou, Guiyao; Sang, Xinzhu; Wu, Qiang; Yan, Binbin; Zhou, Xian; Zhong, Kangping; Wang, Liang; Wang, Kuiru; Yu, Chongxiu; Lu, Chao; Tam, Hwa Yaw; Wai, P K A

    2017-05-01

    In this Letter, polarization-dependent intermodal four-wave mixing (FWM) is demonstrated experimentally in a birefringent multimode photonic crystal fiber (BM-PCF) designed and fabricated in-house. Femtosecond pump pulses at wavelengths ∼800  nm polarized along one of the principal axes of the BM-PCF are coupled into a normal dispersion region away from the zero-dispersion wavelengths of the fundamental guided mode of the BM-PCF. Anti-Stokes and Stokes waves are generated in the 2nd guided mode at visible and near-infrared wavelengths, respectively. For pump pulses at an average input power of 500 mW polarized along the slow axis, the conversion efficiencies ηas and ηs of the anti-Stokes and Stokes waves generated at wavelengths 579.7 and 1290.4 nm are 19% and 14%, respectively. For pump pulses polarized along the fast axis, the corresponding ηas and ηs at 530.4 and 1627 nm are 23% and 18%, respectively. We also observed that fiber bending and intermodal walk-off have a small effect on the polarization-dependent intermodal FWM-based frequency conversion process.

  9. Multiple scattering of polarized light in a turbid medium

    NARCIS (Netherlands)

    Gorodnichev, E. E.; Kuzovlev, A. I.; Rogozkin, D. B.

    2007-01-01

    It is shown that multiple scattering of polarized light in a turbid medium can be represented as independent propagation of three basic modes: intensity and linearly and circularly polarized modes. Weak interaction between the basic modes can be described by perturbation theory and gives rise to "ov

  10. Polarized neutron scattering on HYSPEC: the HYbrid SPECtrometer at SNS

    Energy Technology Data Exchange (ETDEWEB)

    Zaliznyak, Igor [Brookhaven National Laboratory (BNL); Savici, Andrei T [ORNL; Garlea, Vasile O [ORNL; Winn, Barry L [ORNL; Schneelock, John [Brookhaven National Laboratory (BNL); Tranquada, John M. [Brookhaven National Laboratory (BNL); Gu, G. D. [Brookhaven National Laboratory (BNL); Wang, Aifeng [Brookhaven National Laboratory (BNL); Petrovic, C [Brookhaven National Laboratory (BNL)

    2017-01-01

    We describe some of the first polarized neutron scattering measurements performed at HYSPEC spectrometer at the Spallation Neutron Source, Oak Ridge National Laboratory. We discuss details of the instrument setup and the experimental procedures in the mode with the full polarization analysis. Examples of the polarized neutron diffraction and the polarized inelastic neutron data obtained on single crystal samples are presented.

  11. FUNDAMENTALS OF BIOMECHANICS

    Directory of Open Access Journals (Sweden)

    Duane Knudson

    2007-09-01

    Full Text Available DESCRIPTION This book provides a broad and in-depth theoretical and practical description of the fundamental concepts in understanding biomechanics in the qualitative analysis of human movement. PURPOSE The aim is to bring together up-to-date biomechanical knowledge with expert application knowledge. Extensive referencing for students is also provided. FEATURES This textbook is divided into 12 chapters within four parts, including a lab activities section at the end. The division is as follows: Part 1 Introduction: 1.Introduction to biomechanics of human movement; 2.Fundamentals of biomechanics and qualitative analysis; Part 2 Biological/Structural Bases: 3.Anatomical description and its limitations; 4.Mechanics of the musculoskeletal system; Part 3 Mechanical Bases: 5.Linear and angular kinematics; 6.Linear kinetics; 7.Angular kinetics; 8.Fluid mechanics; Part 4 Application of Biomechanics in Qualitative Analysis :9.Applying biomechanics in physical education; 10.Applying biomechanics in coaching; 11.Applying biomechanics in strength and conditioning; 12.Applying biomechanics in sports medicine and rehabilitation. AUDIENCE This is an important reading for both student and educators in the medicine, sport and exercise-related fields. For the researcher and lecturer it would be a helpful guide to plan and prepare more detailed experimental designs or lecture and/or laboratory classes in exercise and sport biomechanics. ASSESSMENT The text provides a constructive fundamental resource for biomechanics, exercise and sport-related students, teachers and researchers as well as anyone interested in understanding motion. It is also very useful since being clearly written and presenting several ways of examples of the application of biomechanics to help teach and apply biomechanical variables and concepts, including sport-related ones

  12. Information security fundamentals

    CERN Document Server

    Blackley, John A; Peltier, Justin

    2004-01-01

    Effective security rules and procedures do not exist for their own sake-they are put in place to protect critical assets, thereby supporting overall business objectives. Recognizing security as a business enabler is the first step in building a successful program.Information Security Fundamentals allows future security professionals to gain a solid understanding of the foundations of the field and the entire range of issues that practitioners must address. This book enables students to understand the key elements that comprise a successful information security program and eventually apply thes

  13. El grupo fundamental

    Directory of Open Access Journals (Sweden)

    Carlos A. Robles Corbalá

    2015-12-01

    Full Text Available En este artículo se aborda un problema clásico para poder detectar si dos espacios topológicos son homeomorfos o no. Para lo cual a cada espacio topológico se le asocia un grupo algebraico, de tal suerte que si los espacios son homeomorfos, entonces los grupos asociados serán isomorfos. Se presenta una construcción del grupo fundamental de un espacio topológico y se enfoca en demostrar que efectivamente es un grupo.

  14. Fundamentals of calculus

    CERN Document Server

    Morris, Carla C

    2015-01-01

    Fundamentals of Calculus encourages students to use power, quotient, and product rules for solutions as well as stresses the importance of modeling skills.  In addition to core integral and differential calculus coverage, the book features finite calculus, which lends itself to modeling and spreadsheets.  Specifically, finite calculus is applied to marginal economic analysis, finance, growth, and decay.  Includes: Linear Equations and FunctionsThe DerivativeUsing the Derivative Exponential and Logarithmic Functions Techniques of DifferentiationIntegral CalculusIntegration TechniquesFunctions

  15. Fundamentals of engineering electromagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nam; Yoon, Youngro; Jun, Sukhee; Jun, Hoin

    2004-08-15

    It indicates fundamentals of engineering electromagnetism. It mentions electromagnetic field model of introduction and International system of units and universal constant, Vector analysis with summary and orthogonal coordinate systems, electrostatic field on Coulomb's law and Gauss's law, electrostatic energy and strength, steady state current with Ohm's law and Joule's law and calculation of resistance, crystallite field with Vector's electrostatic potential, Biot-Savart law and application and Magnetic Dipole, time-Savart and Maxwell equation with potential function and Faraday law of electromagnetic induction, plane electromagnetic wave, transmission line, a wave guide and cavity resonator and antenna arrangement.

  16. Fundamentals of attosecond optics

    CERN Document Server

    Chang, Zenghu

    2011-01-01

    Attosecond optical pulse generation, along with the related process of high-order harmonic generation, is redefining ultrafast physics and chemistry. A practical understanding of attosecond optics requires significant background information and foundational theory to make full use of these cutting-edge lasers and advance the technology toward the next generation of ultrafast lasers. Fundamentals of Attosecond Optics provides the first focused introduction to the field. The author presents the underlying concepts and techniques required to enter the field, as well as recent research advances th

  17. Fundamentals of microwave photonics

    CERN Document Server

    Urick, V J; McKinney , Jason D

    2015-01-01

    A comprehensive resource to designing andconstructing analog photonic links capable of high RFperformanceFundamentals of Microwave Photonics provides acomprehensive description of analog optical links from basicprinciples to applications.  The book is organized into fourparts. The first begins with a historical perspective of microwavephotonics, listing the advantages of fiber optic links anddelineating analog vs. digital links. The second section coversbasic principles associated with microwave photonics in both the RFand optical domains.  The third focuses on analog modulationformats-starti

  18. Mathematical analysis fundamentals

    CERN Document Server

    Bashirov, Agamirza

    2014-01-01

    The author's goal is a rigorous presentation of the fundamentals of analysis, starting from elementary level and moving to the advanced coursework. The curriculum of all mathematics (pure or applied) and physics programs include a compulsory course in mathematical analysis. This book will serve as can serve a main textbook of such (one semester) courses. The book can also serve as additional reading for such courses as real analysis, functional analysis, harmonic analysis etc. For non-math major students requiring math beyond calculus, this is a more friendly approach than many math-centric o

  19. Fundamentals of Project Management

    CERN Document Server

    Heagney, Joseph

    2011-01-01

    With sales of more than 160,000 copies, Fundamentals of Project Management has helped generations of project managers navigate the ins and outs of every aspect of this complex discipline. Using a simple step-by-step approach, the book is the perfect introduction to project management tools, techniques, and concepts. Readers will learn how to: ò Develop a mission statement, vision, goals, and objectives ò Plan the project ò Create the work breakdown structure ò Produce a workable schedule ò Understand earned value analysis ò Manage a project team ò Control and evaluate progress at every stage.

  20. Fundamental concepts of mathematics

    CERN Document Server

    Goodstein, R L

    Fundamental Concepts of Mathematics, 2nd Edition provides an account of some basic concepts in modern mathematics. The book is primarily intended for mathematics teachers and lay people who wants to improve their skills in mathematics. Among the concepts and problems presented in the book include the determination of which integral polynomials have integral solutions; sentence logic and informal set theory; and why four colors is enough to color a map. Unlike in the first edition, the second edition provides detailed solutions to exercises contained in the text. Mathematics teachers and people

  1. Fundamentals of semiconductor devices

    CERN Document Server

    Lindmayer, Joseph

    1965-01-01

    Semiconductor properties ; semiconductor junctions or diodes ; transistor fundamentals ; inhomogeneous impurity distributions, drift or graded-base transistors ; high-frequency properties of transistors ; band structure of semiconductors ; high current densities and mechanisms of carrier transport ; transistor transient response and recombination processes ; surfaces, field-effect transistors, and composite junctions ; additional semiconductor characteristics ; additional semiconductor devices and microcircuits ; more metal, insulator, and semiconductor combinations for devices ; four-pole parameters and configuration rotation ; four-poles of combined networks and devices ; equivalent circuits ; the error function and its properties ; Fermi-Dirac statistics ; useful physical constants.

  2. Fundamental of biomedical engineering

    CERN Document Server

    Sawhney, GS

    2007-01-01

    About the Book: A well set out textbook explains the fundamentals of biomedical engineering in the areas of biomechanics, biofluid flow, biomaterials, bioinstrumentation and use of computing in biomedical engineering. All these subjects form a basic part of an engineer''s education. The text is admirably suited to meet the needs of the students of mechanical engineering, opting for the elective of Biomedical Engineering. Coverage of bioinstrumentation, biomaterials and computing for biomedical engineers can meet the needs of the students of Electronic & Communication, Electronic & Instrumenta

  3. Fundamentals of Cavitation

    CERN Document Server

    Franc, Jean-Pierre

    2005-01-01

    The present book is aimed at providing a comprehensive presentation of cavitation phenomena in liquid flows. It is further backed up by the experience, both experimental and theoretical, of the authors whose expertise has been internationally recognized. A special effort is made to place the various methods of investigation in strong relation with the fundamental physics of cavitation, enabling the reader to treat specific problems independently. Furthermore, it is hoped that a better knowledge of the cavitation phenomenon will allow engineers to create systems using it positively. Examples in the literature show the feasibility of this approach.

  4. Fundamentals of photonics

    CERN Document Server

    Saleh, Bahaa E A

    2007-01-01

    Now in a new full-color edition, Fundamentals of Photonics, Second Edition is a self-contained and up-to-date introductory-level textbook that thoroughly surveys this rapidly expanding area of engineering and applied physics. Featuring a logical blend of theory and applications, coverage includes detailed accounts of the primary theories of light, including ray optics, wave optics, electromagnetic optics, and photon optics, as well as the interaction of photons and atoms, and semiconductor optics. Presented at increasing levels of complexity, preliminary sections build toward more advan

  5. Nanomachines fundamentals and applications

    CERN Document Server

    Wang, Joseph

    2013-01-01

    This first-hand account by one of the pioneers of nanobiotechnology brings together a wealth of valuable material in a single source. It allows fascinating insights into motion at the nanoscale, showing how the proven principles of biological nanomotors are being transferred to artificial nanodevices.As such, the author provides engineers and scientists with the fundamental knowledge surrounding the design and operation of biological and synthetic nanomotors and the latest advances in nanomachines. He addresses such topics as nanoscale propulsions, natural biomotors, molecular-scale machin

  6. Electronic circuits fundamentals & applications

    CERN Document Server

    Tooley, Mike

    2015-01-01

    Electronics explained in one volume, using both theoretical and practical applications.New chapter on Raspberry PiCompanion website contains free electronic tools to aid learning for students and a question bank for lecturersPractical investigations and questions within each chapter help reinforce learning Mike Tooley provides all the information required to get to grips with the fundamentals of electronics, detailing the underpinning knowledge necessary to appreciate the operation of a wide range of electronic circuits, including amplifiers, logic circuits, power supplies and oscillators. The

  7. Fundamentals of Medical Ultrasonics

    CERN Document Server

    Postema, Michiel

    2011-01-01

    This book sets out the physical and engineering principles of acoustics and ultrasound as used for medical applications. It covers the basics of linear acoustics, wave propagation, non-linear acoustics, acoustic properties of tissue, transducer components, and ultrasonic imaging modes, as well as the most common diagnostic and therapeutic applications. It offers students and professionals in medical physics and engineering a detailed overview of the technical aspects of medical ultrasonic imaging, whilst serving as a reference for clinical and research staff.

  8. Single-Mode VCSELs

    Science.gov (United States)

    Larsson, Anders; Gustavsson, Johan S.

    The only active transverse mode in a truly single-mode VCSEL is the fundamental mode with a near Gaussian field distribution. A single-mode VCSEL produces a light beam of higher spectral purity, higher degree of coherence and lower divergence than a multimode VCSEL and the beam can be more precisely shaped and focused to a smaller spot. Such beam properties are required in many applications. In this chapter, after discussing applications of single-mode VCSELs, we introduce the basics of fields and modes in VCSELs and review designs implemented for single-mode emission from VCSELs in different materials and at different wavelengths. This includes VCSELs that are inherently single-mode as well as inherently multimode VCSELs where higher-order modes are suppressed by mode selective gain or loss. In each case we present the current state-of-the-art and discuss pros and cons. At the end, a specific example with experimental results is provided and, as a summary, the most promising designs based on current technologies are identified.

  9. Fiber based polarization filter for radially and azimuthally polarized light.

    Science.gov (United States)

    Jocher, Christoph; Jauregui, Cesar; Voigtländer, Christian; Stutzki, Fabian; Nolte, Stefan; Limpert, Jens; Tünnermann, Andreas

    2011-09-26

    We demonstrate a new fiber based concept to filter azimuthally or radially polarized light. This concept is based on the lifting of the modal degeneracy that takes place in high numerical aperture fibers. In such fibers, the radially and azimuthally polarized modes can be spectrally separated using a fiber Bragg grating. As a proof of principle, we filter azimuthally polarized light in a commercially available fiber in which a fiber Bragg grating has been written by a femtosecond pulsed laser. © 2011 Optical Society of America

  10. The MOND Fundamental Plane

    CERN Document Server

    Cardone, V F; Diaferio, A; Tortora, C; Molinaro, R

    2010-01-01

    Modified Newtonian Dynamics (MOND) has been shown to be able to fit spiral galaxy rotation curves as well as giving a theoretical foundation for empirically determined scaling relations, such as the Tully - Fisher law, without the need for a dark matter halo. As a complementary analysis, one should investigate whether MOND can also reproduce the dynamics of early - type galaxies (ETGs) without dark matter. As a first step, we here show that MOND can indeed fit the observed central velocity dispersion $\\sigma_0$ of a large sample of ETGs assuming a simple MOND interpolating functions and constant anisotropy. We also show that, under some assumptions on the luminosity dependence of the Sersic n parameter and the stellar M/L ratio, MOND predicts a fundamental plane for ETGs : a log - linear relation among the effective radius $R_{eff}$, $\\sigma_0$ and the mean effective intensity $\\langle I_e \\rangle$. However, we predict a tilt between the observed and the MOND fundamental planes.

  11. Testing Our Fundamental Assumptions

    Science.gov (United States)

    Kohler, Susanna

    2016-06-01

    Science is all about testing the things we take for granted including some of the most fundamental aspects of how we understand our universe. Is the speed of light in a vacuum the same for all photons regardless of their energy? Is the rest mass of a photon actually zero? A series of recent studies explore the possibility of using transient astrophysical sources for tests!Explaining Different Arrival TimesArtists illustration of a gamma-ray burst, another extragalactic transient, in a star-forming region. [NASA/Swift/Mary Pat Hrybyk-Keith and John Jones]Suppose you observe a distant transient astrophysical source like a gamma-ray burst, or a flare from an active nucleus and two photons of different energies arrive at your telescope at different times. This difference in arrival times could be due to several different factors, depending on how deeply you want to question some of our fundamental assumptions about physics:Intrinsic delayThe photons may simply have been emitted at two different times by the astrophysical source.Delay due to Lorentz invariance violationPerhaps the assumption that all massless particles (even two photons with different energies) move at the exact same velocity in a vacuum is incorrect.Special-relativistic delayMaybe there is a universal speed for massless particles, but the assumption that photons have zero rest mass is wrong. This, too, would cause photon velocities to be energy-dependent.Delay due to gravitational potentialPerhaps our understanding of the gravitational potential that the photons experience as they travel is incorrect, also causing different flight times for photons of different energies. This would mean that Einsteins equivalence principle, a fundamental tenet of general relativity (GR), is incorrect.If we now turn this problem around, then by measuring the arrival time delay between photons of different energies from various astrophysical sources the further away, the better we can provide constraints on these

  12. Fundamentals of Space Systems

    Science.gov (United States)

    Pisacane, Vincent L.

    2005-06-01

    Fundamentals of Space Systems was developed to satisfy two objectives: the first is to provide a text suitable for use in an advanced undergraduate or beginning graduate course in both space systems engineering and space system design. The second is to be a primer and reference book for space professionals wishing to broaden their capabilities to develop, manage the development, or operate space systems. The authors of the individual chapters are practicing engineers that have had extensive experience in developing sophisticated experimental and operational spacecraft systems in addition to having experience teaching the subject material. The text presents the fundamentals of all the subsystems of a spacecraft missions and includes illustrative examples drawn from actual experience to enhance the learning experience. It included a chapter on each of the relevant major disciplines and subsystems including space systems engineering, space environment, astrodynamics, propulsion and flight mechanics, attitude determination and control, power systems, thermal control, configuration management and structures, communications, command and telemetry, data processing, embedded flight software, survuvability and reliability, integration and test, mission operations, and the initial conceptual design of a typical small spacecraft mission.

  13. Meta-Chirality: Fundamentals, Construction and Applications

    Directory of Open Access Journals (Sweden)

    Xiaoliang Ma

    2017-05-01

    Full Text Available Chiral metamaterials represent a special type of artificial structures that cannot be superposed to their mirror images. Due to the lack of mirror symmetry, cross-coupling between electric and magnetic fields exist in chiral mediums and present unique electromagnetic characters of circular dichroism and optical activity, which provide a new opportunity to tune polarization and realize negative refractive index. Chiral metamaterials have attracted great attentions in recent years and have given rise to a series of applications in polarization manipulation, imaging, chemical and biological detection, and nonlinear optics. Here we review the fundamental theory of chiral media and analyze the construction principles of some typical chiral metamaterials. Then, the progress in extrinsic chiral metamaterials, absorbing chiral metamaterials, and reconfigurable chiral metamaterials are summarized. In the last section, future trends in chiral metamaterials and application in nonlinear optics are introduced.

  14. Meta-Chirality: Fundamentals, Construction and Applications

    Science.gov (United States)

    Ma, Xiaoliang; Pu, Mingbo; Li, Xiong; Guo, Yinghui; Gao, Ping; Luo, Xiangang

    2017-01-01

    Chiral metamaterials represent a special type of artificial structures that cannot be superposed to their mirror images. Due to the lack of mirror symmetry, cross-coupling between electric and magnetic fields exist in chiral mediums and present unique electromagnetic characters of circular dichroism and optical activity, which provide a new opportunity to tune polarization and realize negative refractive index. Chiral metamaterials have attracted great attentions in recent years and have given rise to a series of applications in polarization manipulation, imaging, chemical and biological detection, and nonlinear optics. Here we review the fundamental theory of chiral media and analyze the construction principles of some typical chiral metamaterials. Then, the progress in extrinsic chiral metamaterials, absorbing chiral metamaterials, and reconfigurable chiral metamaterials are summarized. In the last section, future trends in chiral metamaterials and application in nonlinear optics are introduced. PMID:28513560

  15. All-fiber Raman Probe using Higher Order Modes

    DEFF Research Database (Denmark)

    Larsen, Stine Højer Møller; Rishøj, Lars Søgaard; Rottwitt, Karsten

    2013-01-01

    We demonstrate the first all-fiber Raman probe utilizing higher order modes for the excitation. The spectrum of cyclohexane is measured using both the fundamental mode as well as in-fiber-generated Bessel-like modes.......We demonstrate the first all-fiber Raman probe utilizing higher order modes for the excitation. The spectrum of cyclohexane is measured using both the fundamental mode as well as in-fiber-generated Bessel-like modes....

  16. Polarizing cues.

    Science.gov (United States)

    Nicholson, Stephen P

    2012-01-01

    People categorize themselves and others, creating ingroup and outgroup distinctions. In American politics, parties constitute the in- and outgroups, and party leaders hold sway in articulating party positions. A party leader's endorsement of a policy can be persuasive, inducing co-partisans to take the same position. In contrast, a party leader's endorsement may polarize opinion, inducing out-party identifiers to take a contrary position. Using survey experiments from the 2008 presidential election, I examine whether in- and out-party candidate cues—John McCain and Barack Obama—affected partisan opinion. The results indicate that in-party leader cues do not persuade but that out-party leader cues polarize. This finding holds in an experiment featuring President Bush in which his endorsement did not persuade Republicans but it polarized Democrats. Lastly, I compare the effect of party leader cues to party label cues. The results suggest that politicians, not parties, function as polarizing cues.

  17. Digital Fourier analysis fundamentals

    CERN Document Server

    Kido, Ken'iti

    2015-01-01

    This textbook is a thorough, accessible introduction to digital Fourier analysis for undergraduate students in the sciences. Beginning with the principles of sine/cosine decomposition, the reader walks through the principles of discrete Fourier analysis before reaching the cornerstone of signal processing: the Fast Fourier Transform. Saturated with clear, coherent illustrations, "Digital Fourier Analysis - Fundamentals" includes practice problems and thorough Appendices for the advanced reader. As a special feature, the book includes interactive applets (available online) that mirror the illustrations.  These user-friendly applets animate concepts interactively, allowing the user to experiment with the underlying mathematics. For example, a real sine signal can be treated as a sum of clockwise and counter-clockwise rotating vectors. The applet illustration included with the book animates the rotating vectors and the resulting sine signal. By changing parameters such as amplitude and frequency, the reader ca...

  18. Fundamentals of quantum mechanics

    CERN Document Server

    House, J E

    2017-01-01

    Fundamentals of Quantum Mechanics, Third Edition is a clear and detailed introduction to quantum mechanics and its applications in chemistry and physics. All required math is clearly explained, including intermediate steps in derivations, and concise review of the math is included in the text at appropriate points. Most of the elementary quantum mechanical models-including particles in boxes, rigid rotor, harmonic oscillator, barrier penetration, hydrogen atom-are clearly and completely presented. Applications of these models to selected “real world” topics are also included. This new edition includes many new topics such as band theory and heat capacity of solids, spectroscopy of molecules and complexes (including applications to ligand field theory), and small molecules of astrophysical interest.

  19. Fundamental partial compositeness

    CERN Document Server

    Sannino, Francesco

    2016-01-01

    We construct renormalizable Standard Model extensions, valid up to the Planck scale, that give a composite Higgs from a new fundamental strong force acting on fermions and scalars. Yukawa interactions of these particles with Standard Model fermions realize the partial compositeness scenario. Successful models exist because gauge quantum numbers of Standard Model fermions admit a minimal enough 'square root'. Furthermore, right-handed SM fermions have an SU(2)$_R$-like structure, yielding a custodially-protected composite Higgs. Baryon and lepton numbers arise accidentally. Standard Model fermions acquire mass at tree level, while the Higgs potential and flavor violations are generated by quantum corrections. We further discuss accidental symmetries and other dynamical features stemming from the new strongly interacting scalars. If the same phenomenology can be obtained from models without our elementary scalars, they would reappear as composite states.

  20. Lasers Fundamentals and Applications

    CERN Document Server

    Thyagarajan, K

    2010-01-01

    Lasers: Fundamentals and Applications, serves as a vital textbook to accompany undergraduate and graduate courses on lasers and their applications. Ever since their invention in 1960, lasers have assumed tremendous importance in the fields of science, engineering and technology because of their diverse uses in basic research and countless technological applications. This book provides a coherent presentation of the basic physics behind the way lasers work, and presents some of their most important applications in vivid detail. After reading this book, students will understand how to apply the concepts found within to practical, tangible situations. This textbook includes worked-out examples and exercises to enhance understanding, and the preface shows lecturers how to most beneficially match the textbook with their course curricula. The book includes several recent Nobel Lectures, which will further expose students to the emerging applications and excitement of working with lasers. Students who study lasers, ...

  1. Fundamentals of Structural Engineering

    CERN Document Server

    Connor, Jerome J

    2013-01-01

    Fundamentals of Structural Engineering provides a balanced, seamless treatment of both classic, analytic methods and contemporary, computer-based techniques for conceptualizing and designing a structure. The book’s principle goal is to foster an intuitive understanding of structural behavior based on problem solving experience for students of civil engineering and architecture who have been exposed to the basic concepts of engineering mechanics and mechanics of materials. Making it distinct from many other undergraduate textbooks, the authors of this text recognize the notion that engineers reason about behavior using simple models and intuition they acquire through problem solving. The approach adopted in this text develops this type of intuition  by presenting extensive, realistic problems and case studies together with computer simulation, which allows rapid exploration of  how a structure responds to changes in geometry and physical parameters. This book also: Emphasizes problem-based understanding of...

  2. Fundamentals of sustainable neighbourhoods

    CERN Document Server

    Friedman, Avi

    2015-01-01

    This book introduces architects, engineers, builders, and urban planners to a range of design principles of sustainable communities and illustrates them with outstanding case studies. Drawing on the author’s experience as well as local and international case studies, Fundamentals of Sustainable Neighbourhoods presents planning concepts that minimize developments' carbon footprint through compact communities, adaptable and expandable dwellings, adaptable landscapes, and smaller-sized yet quality-designed housing. This book also: Examines in-depth global strategies for minimizing the residential carbon footprint, including district heating, passive solar gain, net-zero residences, as well as preserving the communities' natural assets Reconsiders conceptual approaches in building design and urban planning to promote a better connection between communities and nature Demonstrates practical applications of green architecture Focuses on innovative living spaces in urban environments

  3. Fundamentals of phosphors

    CERN Document Server

    Yen, William M; Yamamoto, Hajime

    2006-01-01

    Drawing from the second edition of the best-selling Handbook of Phosphors, Fundamentals of Phosphors covers the principles and mechanisms of luminescence in detail and surveys the primary phosphor materials as well as their optical properties. The book addresses cutting-edge developments in phosphor science and technology including oxynitride phosphors and the impact of lanthanide level location on phosphor performance.Beginning with an explanation of the physics underlying luminescence mechanisms in solids, the book goes on to interpret various luminescence phenomena in inorganic and organic materials. This includes the interpretation of the luminescence of recently developed low-dimensional systems, such as quantum wells and dots. The book also discusses the excitation mechanisms by cathode-ray and ionizing radiation and by electric fields to produce electroluminescence. The book classifies phosphor materials according to the type of luminescence centers employed or the class of host materials used and inte...

  4. Superconductivity fundamentals and applications

    CERN Document Server

    Buckel, Werner

    2004-01-01

    This is the second English edition of what has become one of the definitive works on superconductivity in German -- currently in its sixth edition. Comprehensive and easy to understand, this introductory text is written especially with the non-specialist in mind. The authors, both long-term experts in this field, present the fundamental considerations without the need for extensive mathematics, describing the various phenomena connected with the superconducting state, with liberal insertion of experimental facts and examples for modern applications. While all fields of superconducting phenomena are dealt with in detail, this new edition pays particular attention to the groundbreaking discovery of magnesium diboride and the current developments in this field. In addition, a new chapter provides an overview of the elements, alloys and compounds where superconductivity has been observed in experiments, together with their major characteristics. The chapter on technical applications has been considerably expanded...

  5. Fundamentals of Fire Phenomena

    DEFF Research Database (Denmark)

    Quintiere, James

    discipline. It covers thermo chemistry including mixtures and chemical reactions; Introduces combustion to the fire protection student; Discusses premixed flames and spontaneous ignition; Presents conservation laws for control volumes, including the effects of fire; Describes the theoretical bases...... analyses. Fire phenomena encompass everything about the scientific principles behind fire behaviour. Combining the principles of chemistry, physics, heat and mass transfer, and fluid dynamics necessary to understand the fundamentals of fire phenomena, this book integrates the subject into a clear...... for empirical aspects of the subject of fire; Analyses ignition of liquids and the importance of evaporation including heat and mass transfer; Features the stages of fire in compartments, and the role of scale modelling in fire. The book is written by Prof. James G. Quintiere from University of Maryland...

  6. Automotive electronics design fundamentals

    CERN Document Server

    Zaman, Najamuz

    2015-01-01

    This book explains the topology behind automotive electronics architectures and examines how they can be profoundly augmented with embedded controllers. These controllers serve as the core building blocks of today’s vehicle electronics. Rather than simply teaching electrical basics, this unique resource focuses on the fundamental concepts of vehicle electronics architecture, and details the wide variety of Electronic Control Modules (ECMs) that enable the increasingly sophisticated "bells & whistles" of modern designs.  A must-have for automotive design engineers, technicians working in automotive electronics repair centers and students taking automotive electronics courses, this guide bridges the gap between academic instruction and industry practice with clear, concise advice on how to design and optimize automotive electronics with embedded controllers.

  7. Fundamentals of Fire Phenomena

    DEFF Research Database (Denmark)

    Quintiere, James

    Understanding fire dynamics and combustion is essential in fire safety engineering and in fire science curricula. Engineers and students involved in fire protection, safety and investigation need to know and predict how fire behaves to be able to implement adequate safety measures and hazard...... analyses. Fire phenomena encompass everything about the scientific principles behind fire behaviour. Combining the principles of chemistry, physics, heat and mass transfer, and fluid dynamics necessary to understand the fundamentals of fire phenomena, this book integrates the subject into a clear...... discipline. It covers thermo chemistry including mixtures and chemical reactions; Introduces combustion to the fire protection student; Discusses premixed flames and spontaneous ignition; Presents conservation laws for control volumes, including the effects of fire; Describes the theoretical bases...

  8. Adiabatic/diabatic polarization beam splitter

    Energy Technology Data Exchange (ETDEWEB)

    DeRose, Christopher; Cai, Hong

    2017-09-12

    The various presented herein relate to an on-chip polarization beam splitter (PBS), which is adiabatic for the transverse magnetic (TM) mode and diabatic for the transverse electric (TE) mode. The PBS comprises a through waveguide and a cross waveguide, wherein an electromagnetic beam comprising TE mode and TM mode components is applied to an input port of the through waveguide. The PBS can be utilized to separate the TE mode component from the TM mode component, wherein the TE mode component exits the PBS via an output port of the through waveguide, and the TM mode component exits the PBS via an output port of the cross waveguide. The PBS has a structure that is tolerant to manufacturing variations and exhibits high polarization extinction ratios over a wide bandwidth.

  9. Polarization-dependent intensity noise in a microchip solid-state laser with spatially coherent polarization vector fields.

    Science.gov (United States)

    Otsuka, Kenju

    2012-10-15

    Polarization-resolved intensity noise has been investigated experimentally in a laser-diode-pumped isotropic microchip solid-state laser possessing spatially coherent polarization vector fields, which are formed by the coherent superposition of a pair of orthogonally polarized Ince-Gauss (IG) modes through the transverse mode locking. A large amount of noise reduction as compared with the total output, which is a coherent state, was observed for the stronger IG mode component by controlling the pump-beam focus.

  10. Fundamentals of semiconductor lasers

    CERN Document Server

    Numai, Takahiro

    2015-01-01

    This book explains physics under the operating principles of semiconductor lasers in detail based on the experience of the author, dealing with the first manufacturing of phase-shifted DFB-LDs and recent research on transverse modes.   The book also bridges a wide gap between journal papers and textbooks, requiring only an undergraduate-level knowledge of electromagnetism and quantum mechanics, and helps readers to understand journal papers where definitions of some technical terms vary, depending on the paper. Two definitions of the photon density in the rate equations and two definitions of the phase-shift in the phase-shifted DFB-LD are explained, and differences in the calculated results are indicated, depending on the definitions.    Readers can understand the physics of semiconductor lasers and analytical tools for Fabry-Perot LDs, DFB-LDs, and VCSELs and will be stimulated to develop semiconductor lasers themselves.

  11. Coherent optical control of polarization with a critical metasurface

    CERN Document Server

    Kang, Ming

    2015-01-01

    We describe the mechanism by which a metamaterial surface can act as an ideal phase-controlled rotatable linear polarizer. With equal-power linearly polarized beams incident on each side of the surface, varying the relative phase rotates the polarization angles of the output beams, while keeping the polarization exactly linear. The explanation is based on coupled-mode theory and the idea of coherent perfect absorption into auxiliary polarization channels. The polarization-rotating behavior occurs at a critical point of the coupled-mode theory, which can be associated with the exceptional point of a parity-time (PT) symmetric effective Hamiltonian.

  12. Fundamentals of ergonomic exoskeleton robots

    NARCIS (Netherlands)

    Schiele, A.

    2008-01-01

    This thesis is the first to provide the fundamentals of ergonomic exoskeleton design. The fundamental theory as well as technology necessary to analyze and develop ergonomic wearable robots interacting with humans is established and validated by experiments and prototypes. The fundamentals are (1) a

  13. Fundamentals of ergonomic exoskeleton robots

    NARCIS (Netherlands)

    Schiele, A.

    2008-01-01

    This thesis is the first to provide the fundamentals of ergonomic exoskeleton design. The fundamental theory as well as technology necessary to analyze and develop ergonomic wearable robots interacting with humans is established and validated by experiments and prototypes. The fundamentals are (1) a

  14. Optical mode switch based on multimode interference couplers

    Science.gov (United States)

    Xiao, Huifu; Deng, Lin; Zhao, Guolin; Liu, Zilong; Meng, Yinghao; Guo, Xiaonan; Liu, Guipeng; Liu, Su; Ding, Jianfeng; Tian, Yonghui

    2017-02-01

    In this paper, we propose an optical mode switch based on two cascaded multimode interference (MMI) couplers. After a fundamental mode divided into two equal-power fundamental modes in the first MMI coupler, the thermo-optic effect is employed to modulate the phase of the two fundamental modes before directed to the next MMI for the purpose of mode switching. By adjusting the electric signals applied to the modulation arms, the proposed device can implement mode switching in three states: (a) one first-order and two fundamental modes simultaneously output, (b) one first-order mode output, and (c) two fundamental modes output. As a result, the simulated excess losses are -0.29 dB, -0.10 dB, and -0.63 dB, respectively.

  15. Mode decomposition evolution equations.

    Science.gov (United States)

    Wang, Yang; Wei, Guo-Wei; Yang, Siyang

    2012-03-01

    Partial differential equation (PDE) based methods have become some of the most powerful tools for exploring the fundamental problems in signal processing, image processing, computer vision, machine vision and artificial intelligence in the past two decades. The advantages of PDE based approaches are that they can be made fully automatic, robust for the analysis of images, videos and high dimensional data. A fundamental question is whether one can use PDEs to perform all the basic tasks in the image processing. If one can devise PDEs to perform full-scale mode decomposition for signals and images, the modes thus generated would be very useful for secondary processing to meet the needs in various types of signal and image processing. Despite of great progress in PDE based image analysis in the past two decades, the basic roles of PDEs in image/signal analysis are only limited to PDE based low-pass filters, and their applications to noise removal, edge detection, segmentation, etc. At present, it is not clear how to construct PDE based methods for full-scale mode decomposition. The above-mentioned limitation of most current PDE based image/signal processing methods is addressed in the proposed work, in which we introduce a family of mode decomposition evolution equations (MoDEEs) for a vast variety of applications. The MoDEEs are constructed as an extension of a PDE based high-pass filter (Europhys. Lett., 59(6): 814, 2002) by using arbitrarily high order PDE based low-pass filters introduced by Wei (IEEE Signal Process. Lett., 6(7): 165, 1999). The use of arbitrarily high order PDEs is essential to the frequency localization in the mode decomposition. Similar to the wavelet transform, the present MoDEEs have a controllable time-frequency localization and allow a perfect reconstruction of the original function. Therefore, the MoDEE operation is also called a PDE transform. However, modes generated from the present approach are in the spatial or time domain and can be

  16. Fundamentals of klystron testing

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, J.W. Jr.

    1978-08-01

    Fundamentals of klystron testing is a text primarily intended for the indoctrination of new klystron group test stand operators. It should significantly reduce the familiarization time of a new operator, making him an asset to the group sooner than has been experienced in the past. The new employee must appreciate the mission of SLAC before he can rightfully be expected to make a meaningful contribution to the group's effort. Thus, the introductory section acquaints the reader with basic concepts of accelerators in general, then briefly describes major physical aspects of the Stanford Linear Accelerator. Only then is his attention directed to the klystron, with its auxiliary systems, and the rudiments of klystron tube performance checks. It is presumed that the reader is acquainted with basic principles of electronics and scientific notation. However, to preserve the integrity of an indoctrination guide, tedious technical discussions and mathematical analysis have been studiously avoided. It is hoped that the new operator will continue to use the text for reference long after his indoctrination period is completed. Even the more experienced operator should find that particular sections will refresh his understanding of basic principles of klystron testing.

  17. GRBs and Fundamental Physics

    Science.gov (United States)

    Petitjean, Patrick; Wang, F. Y.; Wu, X. F.; Wei, J. J.

    2016-12-01

    Gamma-ray bursts (GRBs) are short and intense flashes at the cosmological distances, which are the most luminous explosions in the Universe. The high luminosities of GRBs make them detectable out to the edge of the visible universe. So, they are unique tools to probe the properties of high-redshift universe: including the cosmic expansion and dark energy, star formation rate, the reionization epoch and the metal evolution of the Universe. First, they can be used to constrain the history of cosmic acceleration and the evolution of dark energy in a redshift range hardly achievable by other cosmological probes. Second, long GRBs are believed to be formed by collapse of massive stars. So they can be used to derive the high-redshift star formation rate, which can not be probed by current observations. Moreover, the use of GRBs as cosmological tools could unveil the reionization history and metal evolution of the Universe, the intergalactic medium (IGM) properties and the nature of first stars in the early universe. But beyond that, the GRB high-energy photons can be applied to constrain Lorentz invariance violation (LIV) and to test Einstein's Equivalence Principle (EEP). In this paper, we review the progress on the GRB cosmology and fundamental physics probed by GRBs.

  18. Fundamental Limits of Cooperation

    CERN Document Server

    Lozano, Angel; Andrews, Jeffrey G

    2012-01-01

    Cooperation is viewed as a key ingredient for interference management in wireless systems. This paper shows that cooperation has fundamental limitations. The main result is that even full cooperation between transmitters cannot in general change an interference-limited network to a noise-limited network. The key idea is that there exists a spectral efficiency upper bound that is independent of the transmit power. First, a spectral efficiency upper bound is established for systems that rely on pilot-assisted channel estimation; in this framework, cooperation is shown to be possible only within clusters of limited size, which are subject to out-of-cluster interference whose power scales with that of the in-cluster signals. Second, an upper bound is also shown to exist when cooperation is through noncoherent communication; thus, the spectral efficiency limitation is not a by-product of the reliance on pilot-assisted channel estimation. Consequently, existing literature that routinely assumes the high-power spect...

  19. Revisiting energy efficiency fundamentals

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Lombard, L.; Velazquez, D. [Grupo de Termotecnia, Escuela Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos s/n, 41092 Seville (Spain); Ortiz, J. [Building Research Establishment (BRE), Garston, Watford, WD25 9XX (United Kingdom)

    2013-05-15

    Energy efficiency is a central target for energy policy and a keystone to mitigate climate change and to achieve a sustainable development. Although great efforts have been carried out during the last four decades to investigate the issue, focusing into measuring energy efficiency, understanding its trends and impacts on energy consumption and to design effective energy efficiency policies, many energy efficiency-related concepts, some methodological problems for the construction of energy efficiency indicators (EEI) and even some of the energy efficiency potential gains are often ignored or misunderstood, causing no little confusion and controversy not only for laymen but even for specialists. This paper aims to revisit, analyse and discuss some efficiency fundamental topics that could improve understanding and critical judgement of efficiency stakeholders and that could help in avoiding unfounded judgements and misleading statements. Firstly, we address the problem of measuring energy efficiency both in qualitative and quantitative terms. Secondly, main methodological problems standing in the way of the construction of EEI are discussed, and a sequence of actions is proposed to tackle them in an ordered fashion. Finally, two key topics are discussed in detail: the links between energy efficiency and energy savings, and the border between energy efficiency improvement and renewable sources promotion.

  20. Development on dynamic nuclear polarized targets

    CERN Document Server

    Penttila, S I

    2002-01-01

    Our interest in understanding the spin content of the nucleon has left its marks on the recent development of the dynamic nuclear polarized (DNP) targets. This can be seen from the targets developed at CERN and SLAC for the measurement of the polarized spin structure functions in deep inelastic scattering. The results of the experiments indicated that less than 30% of the nucleon spin is carried by the quarks. This unpredicted small value initiated planning of new polarized target experiments to determine the gluon polarization on the nucleon using polarized real photons and polarized /sup 6/LiD targets. In several facilities very intense polarized photon beams are available at a wide energy range. During the next few years these photon beams with DNP targets will be used to test the fundamental GDH sum rule. Other DNP target developments are also discussed. (61 refs).