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Sarah Forward, Adam Gribble, Sanaz Alali, Andras A Lindenmaier, I Alex Vitkin
Polarimetry is a noninvasive method that uses polarised light to assess biophysical characteristics of tissues. A series of incident polarisation states illuminates a biological sample, and analysis of sample-altered polarisation states enables polarimetric tissue assessment. The resultant information can, for example, help quantitatively differentiate healthy from pathologic tissue. However, most bio-polarimetric assessments are performed using free-space optics with bulky optical components. Extension to flexible fibre-based systems is clinically desirable, but is challenging due to polarisation-altering properties of optical fibres...
September 20, 2017: Scientific Reports
Erich Michael See, Cheryl L Peck, Webster L Santos, Hans D Robinson
We demonstrate the creation of anisotropic patchy silver-nanospheroids (AgNSs) using linearly polarized UV light and a photouncaging o-nitrobenzyl-based ligand, which anchors to the AgNSs by two sulfur bonds. This compound anchors to both gold and silver surfaces, and exposure to a 1 J/cm(2) dose of UV light induces a photouncaging reaction which reveals a primary amine on the surface. By using linearly polarized UV light, we meter the exposure dose such that only the poles of the nanoparticle receive a full dose, limiting the photouncaging reaction primarily to the particle's plasmonic hot spots...
September 14, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Sebastian Schwindl, Birgit Kraus, Jörg Heilmann
A methanolic extract of Juglans regia L. leaves was fractioned by various chromatographic techniques yielding a total of 40 metabolites belonging to megastigmane, tetralone, phenylpropanoid, neolignane and juglone glycosides. Ten unknown megastigmane glucoside derivatives (juglanionosides A-K, 1-10) and six unknown tetralone glucoside derivatives (juglanosides J-O, 11-16) together with 24 known compounds - among them 16 described for the first time in Juglans - were isolated. As characteristic structural feature, the previously undescribed compounds showed acylation of the sugar units with sinapic, ferulic, coumaric, benzoic or salicylic acid...
September 7, 2017: Phytochemistry
Yang Dong, Ji Qi, Honghui He, Chao He, Shaoxiong Liu, Jian Wu, Daniel S Elson, Hui Ma
Polarization imaging has been recognized as a potentially powerful technique for probing the microstructural information and optical properties of complex biological specimens. Recently, we have reported a Mueller matrix microscope by adding the polarization state generator and analyzer (PSG and PSA) to a commercial transmission-light microscope, and applied it to differentiate human liver and cervical cancerous tissues with fibrosis. In this paper, we apply the Mueller matrix microscope for quantitative detection of human breast ductal carcinoma samples at different stages...
August 1, 2017: Biomedical Optics Express
Diana Viegas, Elisabete Fernandes, Raquel Queirós, Dmitri Y Petrovykh, Pieter De Beule
We investigate spectroscopic imaging ellipsometry for monitoring biomolecules at surfaces of nanoparticles. For the modeling of polarimetric light scattering off surface-adsorbed core-shell nanoparticles, we employ an extension of the exact solution for the scattering by particles near a substrate presented by Bobbert and Vlieger, which offers insight beyond that of the Maxwell-Garnett effective medium approximation. Varying thickness and refractive index of a model bio-organic shell results in systematic and characteristic changes in spectroscopic parameters [Formula: see text] and [Formula: see text]...
August 1, 2017: Biomedical Optics Express
Chukwuemeka Okoro, Kimani C Toussaint
We introduce the second-harmonic patterned polarization-analyzed reflection confocal (SPPARC) microscope-a multimodal imaging platform that integrates Mueller matrix polarimetry with reflection confocal and second-harmonic generation (SHG) microscopy. SPPARC microscopy provides label-free three-dimensional (3-D), SHG-patterned confocal images that lend themselves to spatially dependent, linear polarimetric analysis for extraction of rich polarization information based on the Mueller calculus. To demonstrate its capabilities, we use SPPARC microscopy to analyze both porcine tendon and ligament samples and find differences in both circular degree-of-polarization and depolarization parameters...
August 2017: Journal of Biomedical Optics
Gourab Chatterjee, Prashant Kumar Singh, A P L Robinson, D Blackman, N Booth, O Culfa, R J Dance, L A Gizzi, R J Gray, J S Green, P Koester, G Ravindra Kumar, L Labate, Amit D Lad, K L Lancaster, J Pasley, N C Woolsey, P P Rajeev
The transport of hot, relativistic electrons produced by the interaction of an intense petawatt laser pulse with a solid has garnered interest due to its potential application in the development of innovative x-ray sources and ion-acceleration schemes. We report on spatially and temporally resolved measurements of megagauss magnetic fields at the rear of a 50-μm thick plastic target, irradiated by a multi-picosecond petawatt laser pulse at an incident intensity of ~10(20) W/cm(2). The pump-probe polarimetric measurements with micron-scale spatial resolution reveal the dynamics of the magnetic fields generated by the hot electron distribution at the target rear...
August 21, 2017: Scientific Reports
Alexander T Martin, Shane M Nichols, Sichao Li, Melissa Tan, Bart Kahr
Circular birefringence (CB) is generally responsible for only a small perturbation to the state of light polarization in crystals that also exhibit linear birefringence (LB). As such, the magnetoelectric tensor of gyration, which gives rise to CB and optical activity, is less well determined than the electric permittivity tensor in optical models of the Mueller matrix. To visualize the effect of the magnetoelectric tensor on polarimetric measurements, reported here are experimental mappings of the Mueller matrix and of the CB in a new chiral crystal with accidental null LB at an accessible optical frequency...
August 1, 2017: Journal of Applied Crystallography
Hao Guo, Danni Wu, Jubai An
Oil slicks and lookalikes (e.g., plant oil and oil emulsion) all appear as dark areas in polarimetric Synthetic Aperture Radar (SAR) images and are highly heterogeneous, so it is very difficult to use a single feature that can allow classification of dark objects in polarimetric SAR images as oil slicks or lookalikes. We established multi-feature fusion to support the discrimination of oil slicks and lookalikes. In the paper, simple discrimination analysis is used to rationalize a preferred features subset...
August 9, 2017: Sensors
Aziz Tariq, Pengcheng Li, Dongsheng Chen, Donghong Lv, Hui Ma
We propose a physically realizable space for the polarized light scattering measurement using the Stokes-Mueller formalism by a purity-index-depolarization-index (PI-P_{Δ}) plane. The parameter PI is defined from indices of polarimetric purity (IPP), which exhibits the overall magnitude of the polarimetric randomness of a medium, while the depolarization index (P_{Δ}) delineates a proper global degree of polarimetric purity and may also refer to the average measure of depolarization power of the scattering medium...
July 21, 2017: Physical Review Letters
Shinpei Ogawa, Masafumi Kimata
Wavelength- or polarization-selective thermal infrared (IR) detectors are promising for various novel applications such as fire detection, gas analysis, multi-color imaging, multi-channel detectors, recognition of artificial objects in a natural environment, and facial recognition. However, these functions require additional filters or polarizers, which leads to high cost and technical difficulties related to integration of many different pixels in an array format. Plasmonic metamaterial absorbers (PMAs) can impart wavelength or polarization selectivity to conventional thermal IR detectors simply by controlling the surface geometry of the absorbers to produce surface plasmon resonances at designed wavelengths or polarizations...
May 4, 2017: Materials
E Troja, V M Lipunov, C G Mundell, N R Butler, A M Watson, S Kobayashi, S B Cenko, F E Marshall, R Ricci, A Fruchter, M H Wieringa, E S Gorbovskoy, V Kornilov, A Kutyrev, W H Lee, V Toy, N V Tyurina, N M Budnev, D A H Buckley, J González, O Gress, A Horesh, M I Panasyuk, J X Prochaska, E Ramirez-Ruiz, R Rebolo Lopez, M G Richer, C Román-Zúñiga, M Serra-Ricart, V Yurkov, N Gehrels
Newly formed black holes of stellar mass launch collimated outflows (jets) of ionized matter that approach the speed of light. These outflows power prompt, brief and intense flashes of γ-rays known as γ-ray bursts (GRBs), followed by longer-lived afterglow radiation that is detected across the electromagnetic spectrum. Measuring the polarization of the observed GRB radiation provides a direct probe of the magnetic fields in the collimated jets. Rapid-response polarimetric observations of newly discovered bursts have probed the initial afterglow phase, and show that, minutes after the prompt emission has ended, the degree of linear polarization can be as high as 30 per cent-consistent with the idea that a stable, globally ordered magnetic field permeates the jet at large distances from the central source...
July 26, 2017: Nature
Gabriela Statkiewicz-Barabach, Jacek Olszewski, Pawel Mergo, Waclaw Urbanczyk
We present a comprehensive study of an in-line Mach-Zehnder intermodal interferometer fabricated in a boron-doped two-mode highly birefringent microstructured fiber. We observed different interference signals at the output of the interferometer, related to the intermodal interference of the fundamental and the first order modes of the orthogonal polarizations and a beating of the polarimetric signal related to the difference in the group modal birefringence between the fundamental and the first order modes, respectively...
July 18, 2017: Sensors
Ying Yu, Jing Wang, Yu-Ming Wei, Zhang-Kai Zhou, Hai-Qiao Ni, Zhi-Chuan Niu, Xue-Hua Wang, Si-Yuan Yu
We demonstrate the utility of optical second harmonic generation (SHG) polarimetry to perform structural characterization of self-assembled zinc-blende/wurtzite III-V nanowire heterostructures. By analyzing four anisotropic SHG polarimetric patterns, we distinguish between wurtzite (WZ), zinc-blende (ZB) and ZB/WZ mixing III-V semiconducting crystal structures in nanowire systems. By neglecting the surface contributions and treating the bulk crystal within the quasi-static approximation, we can well explain the optical SHG polarimetry from the NWs with diameter from 200-600 nm...
July 6, 2017: Nanotechnology
Charles-Alban Deledalle, Loic Denis, Sonia Tabti, Florence Tupin
Speckle reduction is a longstanding topic in synthetic aperture radar (SAR) imaging. Since most current and planned SAR imaging satellites operate in polarimetric, interferometric, or tomographic modes, SAR images are multi-channel and speckle reduction techniques must jointly process all channels to recover polarimetric and interferometric information. The distinctive nature of SAR signal (complex-valued, corrupted by multiplicative fluctuations) calls for the development of specialized methods for speckle reduction...
September 2017: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
Masahiro Miura, Shuichi Makita, Satoshi Sugiyama, Young-Joo Hong, Yoshiaki Yasuno, Ann E Elsner, Shigeo Tamiya, Rintaro Tsukahara, Takuya Iwasaki, Hiroshi Goto
The purpose of the present study was to evaluate the intraretinal migration of the retinal pigment epithelium (RPE) cells in age-related macular degeneration (AMD) using polarimetry. We evaluated 155 eyes at various AMD stages. Depolarized light images were computed using a polarization-sensitive scanning laser ophthalmoscope (PS-SLO), and the degree of polarization uniformity was calculated using polarization-sensitive optical coherence tomography (OCT). Each polarimetry image was compared with the corresponding autofluorescence (AF) images at 488 nm (SW-AF) and at 787 nm (NIR-AF)...
June 9, 2017: Scientific Reports
Jérémy Vizet, Jean Rehbinder, Stanislas Deby, Stéphane Roussel, André Nazac, Ranya Soufan, Catherine Genestie, Christine Haie-Meder, Hervé Fernandez, François Moreau, Angelo Pierangelo
Mueller polarimetric imaging enables the detection and quantification of modifications of the collagen fibers in the uterine cervix due to the development of a precancerous lesion. This information is not accessible through the use of the classic colposcope, a low magnification microscope used in current practice for cervical cancer screening. However, the in vivo application of Mueller polarimetric imaging poses an instrumental challenge: the device should be sufficiently compact, while still being able to perform fast and accurate acquisition of Mueller matrices in real-world conditions...
June 1, 2017: Scientific Reports
Rodolfo Mastropasqua, Mario Nubile, Niccolò Salgari, Manuela Lanzini, Roberta Calienno, Peter A Mattei, Alessandra Sborgia, Luca Agnifili
A rotating polarimetric 90°-cross linear-filter interferometry system was used to detect the morphological characteristics and features of interference patterns produced in in-vivo corneal stroma in healthy human corneas of 23 subjects. The characteristic corneal isogyres presenting with an evident cross-shaped pattern, grossly aligned with the fixation axis, were observed in all patients with centers within the pupillary dark area, impeding the exact determination of the center point. During the rotational scan in 78...
2017: PloS One
Steffen Wegener, Martin Kaufmann, Lothar W Kroh
Heating aqueous d-glucose model reactions with l-glutamine and l-alanine yielded similar colored solutions. However, size-exclusion chromatography (SEC) revealed that both non-enzymatic browning reactions proceeded differently. Due to a fast occurring cyclization of l-glutamine to pyroglutamic acid, the typical amino-carbonyl reaction was slowed down. However, l-glutamine and l-alanine model reactions showed the same browning index. Closer investigations could prove that l-pyroglutamic acid was able to influence non-enzymatic browning reactions...
October 1, 2017: Food Chemistry
Jan Dupont, Xavier Orlik, Romain Ceolato, Thibault Dartigalongue
Spectralons are reference radiometric samples which exhibit a calibrated reflectance. However, in case of low reflectance samples, the degree of polarization (DOP) of scattered light is hard to characterize. Here, an accurate determination of spectralon spatial depolarization is proposed. Based on a spatially resolved polarimetric imaging system, the polarization state of the scattered light is characterized for every pixel. A statistic distribution analysis is carried out over the entire image. The relative phase shift distribution between two orthogonal components of the scattered electric field clearly exhibits a high sensitivity to the reflectance, the phase statistics following a circular Voigt profile...
May 1, 2017: Optics Express
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