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Lior Neeman, Regev Ben-Zvi, Katya Rechav, Ronit Popovitz-Biro, Dan Oron, Ernesto Joselevich
The growth of horizontal nanowires (NWs) guided by epitaxial and graphoepitaxial relations with the substrate is becoming increasingly attractive owing to the posibility of controlling their position, direction and crystallographic orientation. In guided NWs, as opposed to the extensively characterized vertically grown NWs, there is an increasing need for understanding the relation between structure and properties, specifically the role of the epitaxial relation with the substrate. Furthermore, the uniformity of crystallographic orientation along guided NWs and over the substrate has yet to be checked...
January 17, 2017: Nano Letters
Monica Fallon, Oliver Valero, Marta Pazos, Alfonso Antón
Imaging devices such as the Heidelberg Retinal Tomograph (HRT3), scanning laser polarimetry (GDx), and optical coherence tomography (OCT), play an important role in glaucoma diagnosis. A systematic search for evidence-based data was performed for prospective studies evaluating the diagnostic accuracy of HRT3, GDx and OCT. The diagnostic odds ratio (DOR) was calculated. To compare the accuracy among instruments and parameters, a meta-analysis considering the hierarchical summary receiver operating characteristic (H-SROC) model was performed...
January 13, 2017: Survey of Ophthalmology
Andre Neumann, Jessica Lindlau, Léo Colombier, Manuel Nutz, Sina Najmaei, Jun Lou, Aditya D Mohite, Hisato Yamaguchi, Alexander Högele
Transition metal dichalcogenide semiconductors represent elementary components of layered heterostructures for emergent technologies beyond conventional optoelectronics. In their monolayer form they host electrons with quantized circular motion and associated valley polarization and valley coherence as key elements of opto-valleytronic functionality. Here, we introduce two-dimensional polarimetry as means of direct imaging of the valley pseudospin degree of freedom in monolayer transition metal dichalcogenides...
January 16, 2017: Nature Nanotechnology
Soma Khanra, Kartik Ghosh, Fabio F Ferreira, Wendel A Alves, Francesco Punzo, Ping Yu, Suchismita Guha
Self-assembled l,l-diphenylalanine (FF) peptide micro/nanotubes represent a class of biomimetic materials with a non-centrosymmetric crystal structure and strong piezoelectricity. The peptide nanotubes synthesized by a liquid phase method yield tube lengths in the hundreds of micron range, inner diameters in the few hundred nanometer range, and outer diameters in the 5-15 μm range. Second harmonic generation (SHG) polarimetry from individual self-assembled FF nanotubes is used to obtain the nonlinear (NLO) optical coefficients as a function of the tube diameter and thermal treatment...
January 12, 2017: Physical Chemistry Chemical Physics: PCCP
Bence Kutus, Dániel Ozsvár, Norbert Varga, István Pálinkó, Pál Sipos
The complex formation equilibria between Ca(2+) ions and six carbohydrate derivatives related to d-glucose was quantitatively characterized by potentiometry, freezing point depression and polarimetry. Complexation could not be observed for d-glucose, while weak association was deduced for d-sorbitol and d-mannitol. Stronger complexes are formed with d-gluconate and d-heptagluconate due to the presence of the carboxylate group. In addition to the plausible 1 : 1 species, the 1 : 2 species can also be detected at higher ligand to metal ratios...
January 5, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Sirel Gür Güngör, Ahmet Akman, Almila Sarıgül Sezenöz, Gülşah Tanrıaşıkı
OBJECTIVES: The presence of retinal nerve fiber layer (RNFL) split bundles was recently described in normal eyes scanned using scanning laser polarimetry and by histologic studies. Split bundles may resemble RNFL loss in healthy eyes. The aim of our study was to determine the prevalence of nerve fiber layer split bundles in healthy people. MATERIALS AND METHODS: We imaged 718 eyes of 359 healthy persons with the spectral domain optical coherence tomography in this cross-sectional study...
December 2016: Turkish Journal of Ophthalmology
Peng Li, Yi Zhang, Sheng Liu, Lei Han, Huachao Cheng, Fan Yu, Jianlin Zhao
We report on the generation and control of quasi-Bessel beams having not only a uniform axial intensity but also a longitudinally varying polarization state. Based on the optimization routine of the spatial spectrum of the so-called Durnin ring, we generate quasi-Bessel beams possessing longitudinally variant axial intensity with linear or sinusoidal envelopes. By utilizing a Sagnac interferometer, we create and coaxially composite two orthogonally polarized beams with complementary axial intensities to form quasi-Bessel beams with uniform axial intensity but a longitudinally varying polarization state...
October 15, 2016: Optics Letters
Ivan S Ferreira, Camilo Tello, Miguel Bergano, Thyrso Villela, Domingos Barbosa, George F Smoot
BACKGROUND: We describe the design, the construction and performance of a narrow band ortho-mode transducer, currently used in the 5 GHz polarimetric receiver of the Galactic Emission Mapping project. RESULTS: The ortho-mode transducer was designed to achieve a high degree of transmission within the 400 MHz of the GEM band around the 5 GHz (4.8-5.2 GHz). It is composed of a circular-to-square waveguide transition, a septum polarizer, a thin waveguide coupler and a smooth square-to-rectangular waveguide transition with custom waveguide bends to the output ports...
2016: SpringerPlus
Marie-Elena Kleemann, Jan Mertens, Xuezhi Zheng, Sean Cormier, Vladimir Turek, Felix Benz, Rohit Chikkaraddy, William Deacon, Anna Lombardi, Victor V Moshchalkov, Guy A E Vandenbosch, Jeremy J Baumberg
Polarized optical dark-field spectroscopy is shown to be a versatile noninvasive probe of plasmonic structures that trap light to the nanoscale. Clear spectral polarization splittings are found to be directly related to the asymmetric morphology of nanocavities formed between faceted gold nanoparticles and an underlying gold substrate. Both experiment and simulation show the influence of geometry on the coupled system, with spectral shifts Δλ = 3 nm from single atoms. Analytical models allow us to identify the split resonances as transverse cavity modes, tightly confined to the nanogap...
December 22, 2016: ACS Nano
Delphine Pitrat, Nicolas Daugey, Marion Jean, Nicolas Vanthuyne, Frank Wien, Laurent Ducasse, Nathalie Calin, Thierry Buffeteau, Thierry Brotin
Enantiopure cryptophane-222 derivative (1) devoid of substituents was obtained via high-performance liquid chromatography (HPLC) using chiral stationary phases. The chiroptical properties of 1 were determined from polarimetry, electronic circular dichroism (ECD), synchrotron radiation circular dichroism (SRCD), vibrational circular dichroism (VCD), and Raman optical activity (ROA) experiments and were compared to those of the cryptophane-A (2) derivative. Unusual polarimetric results were obtained for 1 in CHCl3 solvent as the sign of the optical rotation (OR) values changes in the nonresonance region above 365 nm, whereas no change was observed in the CH2Cl2 solvent...
December 15, 2016: Journal of Physical Chemistry. B
Liang Wu, M Salehi, N Koirala, J Moon, S Oh, N P Armitage
Topological insulators have been proposed to be best characterized as bulk magnetoelectric materials that show response functions quantized in terms of fundamental physical constants. Here, we lower the chemical potential of three-dimensional (3D) Bi2Se3 films to ~30 meV above the Dirac point and probe their low-energy electrodynamic response in the presence of magnetic fields with high-precision time-domain terahertz polarimetry. For fields higher than 5 tesla, we observed quantized Faraday and Kerr rotations, whereas the dc transport is still semiclassical...
December 2, 2016: Science
S Reyes Cortes, B Alper, D Alves, M Baruzzo, J Bernardo, P Buratti, R Coelho, C Challis, I Chapman, N Hawkes, T C Hender, J Hobirk, E Joffrin
In this communication we propose a novel diagnostic technique, which uses the collection optics of the JET Motional Stark Effect (MSE) diagnostic, to perform polarimetry marking of observed MHD in high temperature plasma regimes. To introduce the technique, first we will present measurements of the coherence between MSE polarimeter, electron cyclotron emission, and Mirnov coil signals aiming to show the feasibility of the method. The next step consists of measuring the amplitude fluctuation of the raw MSE polarimeter signals, for each MSE channel, following carefully the MHD frequency on Mirnov coil data spectrograms...
November 2016: Review of Scientific Instruments
E Parke, W X Ding, J Duff, D L Brower
Measuring high-frequency fluctuations (above tearing mode frequencies) is important for diagnosing instabilities and transport phenomena. The Madison Symmetric Torus interferometer-polarimeter system has been upgraded to utilize improved planar-diode mixer technology. The new mixers reduce phase noise and allow more sensitive measurements of fluctuations at high frequency. Typical polarimeter rms phase noise values of 0.05°-0.07° are obtained with 400 kHz bandwidth. The low phase noise enables the resolution of fluctuations up to 250 kHz for polarimetry and 600 kHz for interferometry...
November 2016: Review of Scientific Instruments
B H Deng, M Beall, J Schroeder, G Settles, P Feng, J S Kinley, H Gota, M C Thompson
A high sensitivity multi-channel far infrared laser diagnostics with switchable interferometry and polarimetry operation modes for the advanced neutral beam-driven C-2U field-reversed configuration (FRC) plasmas is described. The interferometer achieved superior resolution of 1 × 10(16) m(-2) at >1.5 MHz bandwidth, illustrated by measurement of small amplitude high frequency fluctuations. The polarimetry achieved 0.04° instrument resolution and 0.1° actual resolution in the challenging high density gradient environment with >0...
November 2016: Review of Scientific Instruments
E Viezzer, R Dux, M G Dunne
A new edge beam emission polarimetry diagnostic dedicated to the measurement of the magnetic field line angle has been installed on the ASDEX Upgrade tokamak. The new diagnostic relies on the motional Stark effect and is based on the simultaneous measurement of the polarization direction of the linearly polarized π (parallel to the electric field) and σ (perpendicular to the electric field) lines of the Balmer line Dα. The technical properties of the system are described. The calibration procedures are discussed and first measurements are presented...
November 2016: Review of Scientific Instruments
M C Thompson, H Gota, S Putvinski, M Tuszewski, M Binderbauer
The C-2U experiment at Tri Alpha Energy studies the evolution of field-reversed configuration (FRC) plasmas sustained by neutral beam injection. Data on the FRC plasma performance are provided by a comprehensive suite of diagnostics that includes magnetic sensors, interferometry, Thomson scattering, spectroscopy, bolometry, reflectometry, neutral particle analyzers, and fusion product detectors. While many of these diagnostic systems were inherited from the preceding experiment C-2, C-2U has a variety of new and upgraded diagnostic systems: multi-chord far-infrared polarimetry, multiple fast imaging cameras with selectable atomic line filters, proton detector arrays, and 100 channel bolometer units capable of observing multiple regions of the spectrum simultaneously...
November 2016: Review of Scientific Instruments
R J Smith, T E Weber
The technique of fiber optic pulsed polarimetry, which provides a distributed (local) measurement of the magnetic field along an optical fiber, has been improved to the point where, for the first time, photocathode based optical detection of backscatter is possible with sub-mm spatial resolutions. This has been realized through the writing of an array of deterministic fiber Bragg gratings along the fiber, a so-called backscatter-tailored optical fiber, producing a 34 000-fold increase in backscatter levels over Rayleigh...
November 2016: Review of Scientific Instruments
Shuo Li, Weiqi Jin, Runqiu Xia, Li Li, Xia Wang
The architecture of imaging polarimeters with front-mounted polarizer generally used in infrared imaging polarimetry has significant influence on the imaging process of the systems and further calculation of the polarization information of the observed scenario. In this study, the imaging process of infrared polarization imaging system with front-mounted polarizer is analyzed, a radiation correction method based on the modified infrared imaging model of such a system is proposed, and both laboratory and outdoor experiments are performed to verify its effect...
November 14, 2016: Optics Express
Sayyad Mannan, Mohammad Zaffar, Asima Pradhan, Sumit Basu
The microfibril angle (MFA) giving the orientation of cellulose chains in hard sclerenchymatous bamboo fibers is one of the most important parameters determining the overall strength of the bamboo culm. In this work, Mueller matrix imaging polarimetry is implemented for determining MFA measured over a transverse section of group of fibers and parenchyma cells in bamboo of Dendrocalamus strictus species. The method, based on the Stokes-Mueller formalism, decouples the birefringence exhibited by crystalline cellulose from the clumped polarization parameters using 16 images taken with different polarization states at subcellular resolution...
November 10, 2016: Applied Optics
K Veyrinas, V Gruson, S J Weber, L Barreau, T Ruchon, J-F Hergott, J-C Houver, R R Lucchese, P Salières, D Dowek
Due to the intimate anisotropic interaction between an XUV light field and a molecule resulting in photoionization (PI), molecular frame photoelectron angular distributions (MFPADs) are most sensitive probes of both electronic/nuclear dynamics and the polarization state of the ionizing light field. Consequently, they encode the complex dipole matrix elements describing the dynamics of the PI transition, as well as the three normalized Stokes parameters s1, s2, s3 characterizing the complete polarization state of the light, operating as molecular polarimetry...
December 16, 2016: Faraday Discussions
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