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Polarimetry

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https://www.readbyqxmd.com/read/28191819/snapshot-linear-stokes-imaging-spectropolarimeter-using-division-of-focal-plane-polarimetry-and-integral-field-spectroscopy
#1
Tingkui Mu, Shaun Pacheco, Zeyu Chen, Chunmin Zhang, Rongguang Liang
In this paper, the design and experimental demonstration of a snapshot linear-Stokes imaging spectropolarimeter (SLSIS) is presented. The SLSIS, which is based on division-of-focal-plane polarimetry with four parallel linear polarization channels and integral field spectroscopy with numerous slit dispersive paths, has no moving parts and provides video-rate Stokes-vector hyperspectral datacubes. It does not need any scanning in the spectral, spatial or polarization dimension and offers significant advantages of rapid reconstruction without heavy computation during post-processing...
February 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28187977/retinal-and-optic-nerve-degeneration-in-patients-with-multiple-sclerosis-followed-up-for-5-years
#2
Elena Garcia-Martin, Jose R Ara, Jesus Martin, Carmen Almarcegui, Isabel Dolz, Elisa Vilades, Laura Gil-Arribas, Francisco J Fernandez, Vicente Polo, Jose M Larrosa, Luis E Pablo, Maria Satue
PURPOSE: To quantify retinal nerve fiber layer (RNFL) changes in patients with multiple sclerosis (MS) and healthy controls with a 5-year follow-up and to analyze correlations between disability progression and RNFL degeneration. DESIGN: Observational and longitudinal study. PARTICIPANTS: One hundred patients with relapsing-remitting MS and 50 healthy controls. METHODS: All participants underwent a complete ophthalmic and electrophysiologic exploration and were re-evaluated annually for 5 years...
February 7, 2017: Ophthalmology
https://www.readbyqxmd.com/read/28176895/advanced-endoscopic-imaging-in-gastric-neoplasia-and-preneoplasia
#3
Jonathan W J Lee, Lee Guan Lim, Khay Guan Yeoh
Conventional white light endoscopy remains the current standard in routine clinical practice for early detection of gastric cancer. However, it may not accurately diagnose preneoplastic gastric lesions. The technological advancements in the field of endoscopic imaging for gastric lesions are fast growing. This article reviews currently available advanced endoscopic imaging modalities, in particular chromoendoscopy, narrow band imaging and confocal laser endomicroscopy, and their corresponding evidence shown to improve diagnosis of preneoplastic gastric lesions...
2017: BMJ Open Gastroenterology
https://www.readbyqxmd.com/read/28168045/transient-peripapillary-retinoschisis-in-glaucomatous-eyes
#4
Josine van der Schoot, Koenraad A Vermeer, Hans G Lemij
Purpose. To investigate transient focal microcystic retinoschisis in glaucomatous eyes in images obtained with several imaging techniques used in daily glaucoma care. Methods. Images of 117 glaucoma patients and 91 healthy subjects participating in a large prospective follow-up study into glaucoma imaging were reviewed. Participants were measured with spectral domain optical coherence tomography (SD-OCT), scanning laser polarimetry (SLP), scanning laser tomography (SLT), and standard automated perimetry (SAP)...
2017: Journal of Ophthalmology
https://www.readbyqxmd.com/read/28157922/liquid-crystal-based-mueller-matrix-spectral-imaging-polarimetry-for-parameterizing-mineral-structural-organization
#5
James C Gladish, Donald D Duncan
Herein, we discuss the remote assessment of the subwavelength organizational structure of a medium. Specifically, we use spectral imaging polarimetry, as the vector nature of polarized light enables it to interact with optical anisotropies within a medium, while the spectral aspect of polarization is sensitive to small-scale structure. The ability to image these effects allows for inference of spatial structural organization parameters. This work describes a methodology for revealing structural organization by exploiting the Stokes/Mueller formalism and by utilizing measurements from a spectral imaging polarimeter constructed from liquid crystal variable retarders and a liquid crystal tunable filter...
January 20, 2017: Applied Optics
https://www.readbyqxmd.com/read/28113877/automated-diagnosis-of-glaucoma-using-empirical-wavelet-transform-and-correntropy-features-extracted-from-fundus-images
#6
Shishir Maheshwari, Ram Bilas Pachori, U Rajendra Acharya
Glaucoma is an ocular disorder caused due to increased fluid pressure in the optic nerve. It damages the optic nerve subsequently causes loss of vision. The available scanning methods are Heidelberg Retinal Tomography (HRT), Scanning Laser Polarimetry (SLP) and Optical Coherence Tomography (OCT). These methods are expensive and require experienced clinicians to use them. So, there is a need to diagnose glaucoma accurately with low cost. Hence, in this paper, we have presented a new methodology for an automated diagnosis of glaucoma using digital fundus images based on Empirical Wavelet Transform (EWT)...
March 22, 2016: IEEE Journal of Biomedical and Health Informatics
https://www.readbyqxmd.com/read/28107928/determination-of-d-lactide-content-in-lactide-stereoisomeric-mixture-using-gas-chromatography-polarimetry
#7
Lidong Feng, Xinchao Bian, Zhiming Chen, Sheng Xiang, Yanlong Liu, Bin Sun, Gao Li, Xuesi Chen
An analytical method has been proposed to quantify the D-lactide content in a lactide stereoisomeric mixture using combined gas chromatography and polarimetry (GC- polarimetry). As for a lactide stereoisomeric mixture, meso-lactide can be determined quantitatively using GC, but D- and L-lactides cannot be separated by the given GC system. The composition of a lactide stereoisomeric mixture is directly relative to its specific optical rotation. The specific optical rotations of neat L-lactide were obtained in different solutions, which were -266...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28105702/hydrodynamic-effects-in-soft-matter-self-assembly-the-case-of-j-aggregates-of-amphiphilic-porphyrins
#8
REVIEW
Josep M Ribo, Zoubir El-Hachemi, Oriol Arteaga, Adolf Canillas, Joaquim Crusats
Chiral J-aggregates of achiral amphiphilic porphyrins (4-sulfonatophenyl and aryl meso-substituted porphyrins) show several effects under the hydrodynamic forces of common stirring. These effects can be classified as pure mechanic (e. g. elasticity, plasticity and breaking of the self-assembly non-covalent bonding) and chemically selective as detected in the formation/growth of the nanoparticles. Diastereoselective, enantioselective and, depending on the sign of chiral shear forces, even enantiospecific selections have been described...
January 20, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28094977/crystallographic-mapping-of-guided-nanowires-by-second-harmonic-generation-polarimetry
#9
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 possibility 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...
February 8, 2017: Nano Letters
https://www.readbyqxmd.com/read/28093287/diagnostic-accuracy-of-imaging-devices-in-glaucoma-a-meta-analysis
#10
REVIEW
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
https://www.readbyqxmd.com/read/28092378/opto-valleytronic-imaging-of-atomically-thin-semiconductors
#11
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
https://www.readbyqxmd.com/read/28079210/probing-nonlinear-optical-coefficients-in-self-assembled-peptide-nanotubes
#12
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
https://www.readbyqxmd.com/read/28054068/ml-and-ml2-complex-formation-between-ca-ii-and-d-glucose-derivatives-in-aqueous-solutions
#13
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
https://www.readbyqxmd.com/read/28050324/prevalence-of-split-nerve-fiber-layer-bundles-in-healthy-people-imaged-with-spectral-domain-optical-coherence-tomography
#14
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
https://www.readbyqxmd.com/read/28005899/quasi-bessel-beams-with-longitudinally-varying-polarization-state-generated-by-employing-spectrum-engineering
#15
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
https://www.readbyqxmd.com/read/27995046/a-c-band-broadband-ortho-mode-transducer-for-radioastronomy-polarimetry
#16
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
https://www.readbyqxmd.com/read/27983796/revealing-nanostructures-through-plasmon-polarimetry
#17
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
https://www.readbyqxmd.com/read/27973824/unusual-chiroptical-properties-of-the-cryptophane-222-skeleton
#18
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
https://www.readbyqxmd.com/read/27934759/quantized-faraday-and-kerr-rotation-and-axion-electrodynamics-of-a-3d-topological-insulator
#19
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
https://www.readbyqxmd.com/read/27910694/mhd-marking-using-the-mse-polarimeter-optics-in-ilw-jet-plasmas
#20
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
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