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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
François Goudail, Matthieu Boffety
We address the comparison of contrast improvement obtained with a fully adaptive polarimetric imager and the best channel of a static polarimetric imager in the presence of both intensity and polarization differences between the target and the background. We develop an in-depth quantitative study of the performance loss incurred by a static imager compared to a fully adaptive one in this case. These results are useful to make a well-informed choice between these two polarimetric imaging architectures in a given application...
September 1, 2016: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Raphaël Turcotte, Danette J Rutledge, Erik Bélanger, Dorothy Dill, Wendy B Macklin, Daniel C Côté
Myelin plays an essential role in the nervous system and its disruption in diseases such as multiple sclerosis may lead to neuronal death, thus causing irreversible functional impairments. Understanding myelin biology is therefore of fundamental and clinical importance, but no tools currently exist to describe the fine spatial organization of myelin sheaths in vivo. Here we demonstrate intravital quantification of the myelin molecular structure using a microscopy method based on polarization-resolved coherent Raman scattering...
2016: Scientific Reports
Jose Luis Vilas, Jose Antonio Sanchez-Martin, Eusebio Bernabeu
The temperature dependence of the birefringence in a suspended core fiber (SCF) has been experimentally analyzed by using a polarimetric setup. The used configuration consists of two linear polarizers and the SCF as birefringent medium. A theoretical study based on Jones matrices has been carried out to analyze the experimental observed behavior. For this, a polarimetric all-fiber configuration was used whose sensitivity depends on the wavelength variation with temperature. Results obtained show that it is strongly affected when the air holes of SCF are partially filled with ethanol...
August 10, 2016: Applied Optics
Suman Singha, Rudolf Ressel
Use of polarimetric SAR data for offshore pollution monitoring is relatively new and shows great potential for operational offshore platform monitoring. This paper describes the development of an automated oil spill detection chain for operational purposes based on C-band (RADARSAT-2) and X-band (TerraSAR-X) fully polarimetric images, wherein we use polarimetric features to characterize oil spills and look-alikes. Numbers of near coincident TerraSAR-X and RADARSAT-2 images have been acquired over offshore platforms...
November 15, 2016: Marine Pollution Bulletin
Huijie Zhao, Wujian Xu
The polarization patterns of skylight which arise due to the scattering of sunlight in the atmosphere can be used by many insects for deriving compass information. Inspired by insects' polarized light compass, scientists have developed a new kind of navigation method. One of the key techniques in this method is the polarimetric sensor which is used to acquire direction information from skylight. In this paper, a polarization navigation sensor is proposed which imitates the working principles of the polarization vision systems of insects...
2016: Sensors
Bruce C Hamper, Michael P Mannino, Melissa E Mueller, Liam T Harrison, Christopher D Spilling
Chromatographic separation of the enantiomers of parent compounds dimethyl α-hydroxyallyl phosphonate and 1-(dimethoxyphosphoryl) allyl methyl carbonate was demonstrated by high-performance liquid chromatography (HPLC) using Chiralpak AS-H and ad-H chiral stationary phases (CSP), respectively, using a combination of UV, polarimetric, and refractive index detectors. A comparison was made of the separation efficiency and elution order of enantiomeric α-hydroxyallyl phosphonates and their carbonate derivatives on commercially available polysaccharide AS, ad, OD, IC-3, and Whelk-O 1 CSPs...
September 2016: Chirality
Jacob A Martin, Kevin C Gross
Current material identification techniques rely on estimating reflectivity or emissivity which vary with viewing angle. As off-nadir remote sensing platforms become increasingly prevalent, techniques robust to changing viewing geometries are desired. A technique leveraging polarimetric hyperspectral imaging (P-HSI), to estimate complex index of refraction, N̂(ν̃), an inherent material property, is presented. The imaginary component of N̂(ν̃) is modeled using a small number of "knot" points and interpolation at in-between frequencies ν̃...
August 8, 2016: Optics Express
Elad Segal, Adam Weissman, David Gachet, Adi Salomon
Metallic hole arrays have been recently used for color generation and filtering due to their reliability and color tunability. However, color generation is still limited to several microns. Understanding the interaction between the individual elements of the whole nanostructure may push the resolution to the sub-micron level. Herein, we study the hybridization between silver nanocavities in order to obtain active color generation at the micron scale. To do so, we use five identical triangular cavities which are separated by hundreds of nanometers from each other...
August 18, 2016: Nanoscale
Dénes Száz, Alexandra Farkas, András Barta, Balázs Kretzer, Ádám Egri, Gábor Horváth
The theory of sky-polarimetric Viking navigation has been widely accepted for decades without any information about the accuracy of this method. Previously, we have measured the accuracy of the first and second steps of this navigation method in psychophysical laboratory and planetarium experiments. Now, we have tested the accuracy of the third step in a planetarium experiment, assuming that the first and second steps are errorless. Using the fists of their outstretched arms, 10 test persons had to estimate the elevation angles (measured in numbers of fists and fingers) of black dots (representing the position of the occluded Sun) projected onto the planetarium dome...
July 2016: Proceedings. Mathematical, Physical, and Engineering Sciences
Minjie Wan, Guohua Gu, Weixian Qian, Kan Ren, Qian Chen
A novel method to optimize the polarization state of a polarimetric imaging system is proposed to solve the problem of target/background contrast enhancement in an outdoor environment adaptively. First, the last three elements of the Stokes vector are selected to be the observed object's polarization features, the discriminant projection of which is regarded as the detecting function of our imaging system. Then, the polarization state of the system, which can be seen as a physical classifier, is calculated by training samples with a support vector machine method...
July 20, 2016: Applied Optics
Peter Westphal, Johannes-Maria Kaltenbach, Kai Wicker
A good understanding of the corneal birefringence properties is essential for polarimetric glucose monitoring in the aqueous humor of the eye. Therefore, we have measured complete 16-element Mueller matrices of single-pass transitions through nine porcine corneas in-vitro, spectrally resolved in the range 300…1000 nm. These ellipsometric measurements have been performed at several angles of incidence at the apex and partially at the periphery of the corneas. The Mueller matrices have been decomposed into linear birefringence, circular birefringence (i...
April 1, 2016: Biomedical Optics Express
S Gupta Roy, O M Awartani, P Sen, B T O'Connor, M W Kudenov
Polarimetry has widespread applications within atmospheric sensing, telecommunications, biomedical imaging, and target detection. Several existing methods of imaging polarimetry trade off the sensor's spatial resolution for polarimetric resolution, and often have some form of spatial registration error. To mitigate these issues, we have developed a system using oriented polymer-based organic photovoltaics (OPVs) that can preferentially absorb linearly polarized light. Additionally, the OPV cells can be made semitransparent, enabling multiple detectors to be cascaded along the same optical axis...
June 27, 2016: Optics Express
Olivier Morel, Ralph Seulin, David Fofi
This paper presents a complete and original calibration framework for the three-CCD polarimetric cameras. These Division-of-Amplitude imaging polarimeters provide polarization images in real-time and open new applications in robotics. In order to fully exploit properties from polarization images, the sensor has to be calibrated leading sometimes to a tedious task that has to be undertaken with specific optical devices in a controlled environment. The proposed framework relies only on the use of a tablet and enables both to calibrate the geometric and the polarization settings of the camera...
June 13, 2016: Optics Express
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