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P Shi, J Chen, L Gao, Y Liu, H Liu, Y N Zhou, G Zhuang
The multi-channel three-wave polarimeter-interferometer system on J-TEXT tokamak has been exploited to measure far-forward collective scattering from electron density fluctuations. The diagnostic utilizes far infrared lasers operated at 432 μm with 17-channel vertical chords (3 cm chord spacing), covering the entire cross section of plasma. Scattering laser power is measured using a high-sensitivity Schottky planar diode mixer which can also detect polarimetric and interferometric phase simultaneously. The system provides a line-integrated measurement of density fluctuations with maximum measurable wave number: k⊥max ≤ 2 cm(-1) and time response up to 350 kHz...
November 2016: Review of Scientific Instruments
H Q Liu, J P Qian, Y X Jie, W X Ding, D L Brower, Z Y Zou, W M Li, H Lian, S X Wang, Y Yang, L Zeng, T Lan, Y Yao, L Q Hu, X D Zhang, B N Wan
A double-pass, radially viewing, far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique has been implemented for diagnosing the plasma current and electron density profiles in the Experimental Advanced Superconducting Tokamak (EAST). POINT has been operated routinely during the most recent experimental campaign and provides continuous 11 chord line-integrated Faraday effect and density measurement throughout the entire plasma discharge for all heating schemes and all plasma conditions (including ITER relevant scenario development)...
November 2016: Review of Scientific Instruments
Ahmad Golaraei, Lukas Kontenis, Richard Cisek, Danielle Tokarz, Susan J Done, Brian C Wilson, Virginijus Barzda
Second-harmonic generation (SHG) double Stokes-Mueller polarimetric microscopy is applied to study the alteration of collagen ultrastructure in a tissue microarray containing three pathological human breast cancer types with differently overexpressed estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor 2 (HER2). Kleinman symmetry is experimentally validated in breast tissue for 1028 nm laser wavelength and it has been shown that measurements with only linearly polarized incoming and outgoing states can determine molecular nonlinear susceptibility tensor component ratio, average in-plane orientation of collagen fibers and degree of linear polarization of SHG...
October 1, 2016: Biomedical Optics Express
Chunmin Zhang, Qiwei Li, Tingyu Yan, Tingkui Mu, Yutong Wei
A high throughput static channeled interference imaging spectropolarimeter (CIISP) over 480-960nm spectral range is presented. The CIISP system includes two birefringent retarders and a Savart interferometer employing tempo-spatially mixed modulated mode with no internal moving parts, and offers a robust system and a high optical throughput to resist the instrument noise. The optical layout and operation of the CIISP sensor are presented in addition to the radiometric, spectral and improved polarimetric calibration techniques used with the system...
October 3, 2016: Optics Express
Fei Hu, Yayun Cheng, Liangqi Gui, Liang Wu, Xinyi Zhang, Xiaohui Peng, Jinlong Su
The polarization properties of thermal millimeter-wave emission capture inherent information of objects, e.g., material composition, shape, and surface features. In this paper, a polarization-based material-classification technique using passive millimeter-wave polarimetric imagery is presented. Linear polarization ratio (LPR) is created to be a new feature discriminator that is sensitive to material type and to remove the reflected ambient radiation effect. The LPR characteristics of several common natural and artificial materials are investigated by theoretical and experimental analysis...
November 1, 2016: Applied Optics
Jian Liang, Wenfei Zhang, Liyong Ren, Haijuan Ju, Enshi Qu
Polarimetric dehazing methods have proven effective in enhancing the quality of chromatic hazy images. Considering that the infrared radiance has a better capacity for traveling through the haze, in this paper we propose a polarimetric dehazing method based on visible and infrared image fusion to improve the visibility of hazy images, especially for dense haze conditions. Experimental results demonstrate that the visibility of hazy images can be effectively enhanced, and the color information can be finely maintained...
October 10, 2016: Applied Optics
Dongqing Peng, Haijian Zhang, Wei Guo, Wen Yang
Based on Time-Frequency (TF) analysis and a-contrario theory, this paper presents a new approach for extraction of linear arranged power transmission tower series in Polarimetric Synthetic Aperture Radar (PolSAR) images. Firstly, the PolSAR multidimensional information is analyzed using a linear TF decomposition approach. The stationarity of each pixel is assessed by testing the maximum likelihood ratio statistics of the coherency matrix. Then, based on the maximum likelihood log-ratio image, a Cell-Averaging Constant False Alarm Rate (CA-CFAR) detector with Weibull clutter background and a post-processing operator is used to detect point-like targets in the image...
November 5, 2016: Sensors
J J Lima, A Aguilar, F G Sánchez, A N Díaz
This work reports a new analytical approach for monitoring the enantiomeric ratios of styrene glycol (SG), encountered during the manufacture of plastics, by chiral liquid chromatography and the application as a biomarker for exposure to styrene. The isomers were separated using an AGP column running in the reverse phase and isocratic mode with a mobile phase consisting of 20 mM phosphate buffer saline (pH 4.15) and methanol at a flow rate of 0.8 mL/min. Photometric, polarimetric, and circular dichroism detectors were employed...
November 4, 2016: Chemosphere
Bence Kutus, Ákos Buckó, Gábor Peintler, István Pálinkó, Pál Sipos
The Ca(ii)-complexation and acid-base properties of l-gulonic acid (HGul), a diastereomer of d-gluconic acid (HGluc) differing only in the configurations of C2 and C5 have been investigated via(1)H and (13)C NMR spectroscopies, Ca-ISE- and pH-potentiometry, polarimetry and freezing point depression. Data obtained for Gul(-)/HGul have been compared with those of Gluc(-)/HGluc. It was found that some properties (acid dissociation constant, the stoichiometry and formation constants of the Ca(ii)-complexes) were insensitive to the difference in the configuration...
November 1, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Swarupananda Pradhan
The three axis vector magnetic field measurement based on the interaction of a single elliptically polarized light beam with an atomic system is described. The magnetic field direction dependent atomic responses are extracted by the polarimetric detection in combination with laser frequency modulation and magnetic field modulation techniques. The magnetometer geometry offers additional critical requirements like compact size and large dynamic range for space application. Further, the three axis magnetic field is measured using only the reflected signal (one polarization component) from the polarimeter and thus can be easily expanded to make spatial array of detectors and/or high sensitivity field gradient measurement as required for biomedical application...
September 2016: Review of Scientific Instruments
E Villa, J Cagigas, B Aja, L de la Fuente, E Artal
A 30% bandwidth phase shifter with four phase states is designed to be integrated in a radio astronomy receiver. The circuit has two 90° out-of-phase microwave phase-shifting branches which are combined by Wilkinson power dividers. Each branch is composed of a 180° phase shifter and a band-pass filter. The 180° phase shifter is made of cascaded hybrid rings with microwave PIN diodes as switching devices. The 90° phase shift is achieved with the two band-pass filters. Experimental characterization has shown significant results, with average phase shift values of -90...
September 2016: Review of Scientific Instruments
Djordje Mirkovic, Phillip M Stepanian, Jeffrey F Kelly, Phillip B Chilson
The radar scattering characteristics of aerial animals are typically obtained from controlled laboratory measurements of a freshly harvested specimen. These measurements are tedious to perform, difficult to replicate, and typically yield only a small subset of the full azimuthal, elevational, and polarimetric radio scattering data. As an alternative, biological applications of radar often assume that the radar cross sections of flying animals are isotropic, since sophisticated computer models are required to estimate the 3D scattering properties of objects having complex shapes...
October 20, 2016: Scientific Reports
Yue Zhang, Huanxin Zou, Tiancheng Luo, Xianxiang Qin, Shilin Zhou, Kefeng Ji
The superpixel segmentation algorithm, as a preprocessing technique, should show good performance in fast segmentation speed, accurate boundary adherence and homogeneous regularity. A fast superpixel segmentation algorithm by iterative edge refinement (IER) works well on optical images. However, it may generate poor superpixels for Polarimetric synthetic aperture radar (PolSAR) images due to the influence of strong speckle noise and many small-sized or slim regions. To solve these problems, we utilized a fast revised Wishart distance instead of Euclidean distance in the local relabeling of unstable pixels, and initialized unstable pixels as all the pixels substituted for the initial grid edge pixels in the initialization step...
October 13, 2016: Sensors
Irene Estévez, Victor Sopo, Angel Lizana, Alex Turpin, Juan Campos
We propose a new complete snapshot Stokes polarimeter based on a single biaxial crystal. It presents different strengths (snapshot, complete polarimetric measurements, large data redundancy, and high sensitivity) in a simple and compact optical arrangement. The polarimeter is experimentally implemented and analyzed in terms of accuracy and repeatability.
October 1, 2016: Optics Letters
Artur Carnicer, Oriol Arteaga, Josep M Suñé-Negre, Bahram Javidi
The counterfeiting of pharmaceutical products represents concerns for both industry and the safety of the general public. Falsification produces losses to companies and poses health risks for patients. In order to detect fake pharmaceutical tablets, we propose producing film-coated tablets with gold nanoparticle encoding. These coated tablets contain unique polarimetric signatures. We present experiments to show that ellipsometric optical techniques, in combination with machine learning algorithms, can be used to distinguish genuine and fake samples...
October 1, 2016: Optics Letters
A Battaglia, K Mroz, Tim Lang, F Tridon, S Tanelli, Lin Tian, Gerald M Heymsfield
Due to the large natural variability of its microphysical properties, the characterization of solid precipitation is a longstanding problem. Since in situ observations are unavailable in severe convective systems, innovative remote sensing retrievals are needed to extend our understanding of such systems. This study presents a novel technique able to retrieve the density, mass, and effective diameter of graupel and hail in severe convection through the combination of airborne microwave remote sensing instruments...
August 27, 2016: Journal of Geophysical Research. Atmospheres: JGR
Slobodan J Petricevic, Pedja M Mihailovic
Compensation of the temperature dependence of the Verdet constant in a polarimetric extrinsic Faraday sensor is of major importance for applying the magneto-optical effect to AC current measurements and magnetic field sensing. This paper presents a method for compensating the temperature effect on the Faraday rotation in a Bi12GeO20 crystal by sensing its optical activity effect on the polarization of a light beam. The method measures the temperature of the same volume of crystal that effects the beam polarization in a magnetic field or current sensing process...
September 30, 2016: Sensors
Feng Lu, Jongwon Lee, Aiting Jiang, Seungyong Jung, Mikhail A Belkin
Polarimetric imaging is widely used in applications from material analysis to biomedical diagnostics, vision and astronomy. The degree of circular polarization, or light ellipticity, is associated with the S3 Stokes parameter which is defined as the difference in the intensities of the left- and right-circularly polarized components of light. Traditional way of determining this parameter relies on using several external optical elements, such as polarizers and wave plates, along with conventional photodetectors, and performing at least two measurements to distinguish left- and right-circularly polarized light components...
October 5, 2016: Nature Communications
Masahiro Yamanari, Satoru Tsuda, Taiki Kokubun, Yukihiro Shiga, Kazuko Omodaka, Naoko Aizawa, Yu Yokoyama, Noriko Himori, Shiho Kunimatsu-Sanuki, Kazuichi Maruyama, Hiroshi Kunikata, Toru Nakazawa
Estimation of polarimetric parameters has been a fundamental issue to assess biological tissues that have form birefringence or polarization scrambling in polarization-sensitive optical coherence tomography (PS-OCT). We present a mathematical framework to provide a maximum likelihood estimation of the target covariance matrix and its incoherent target decomposition to estimate a Jones matrix of a dominant scattering mechanism, called Cloude-Pottier decomposition, thereby deriving the phase retardation and the optic axis of the sample...
September 1, 2016: Biomedical Optics Express
Aymeric Le Gratiet, Matthieu Dubreuil, Sylvain Rivet, Yann Le Grand
A full Mueller polarimeter was implemented on a commercial laser-scanning microscope. The new polarimetric microscope is based on high-speed polarization modulation by spectral coding using a wavelength-swept laser as a source. Calibration as well as estimation of the measurement errors of the device are reported. The acquisition of Mueller images at the speed of a scanning microscope is demonstrated for the first time. Mueller images of mineral and biological samples illustrate this new polarimetric microscopy...
September 15, 2016: Optics Letters
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