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Thomas Würthwein, Maximilian Brinkmann, Tim Hellwig, Carsten Fallnich
We present the simultaneous detection of the spectrum and the complete polarization state of a multiplex coherent anti-Stokes Raman scattering signal with a fast division-of-amplitude spectro-polarimeter. The spectro-polarimeter is based on a commercial imaging spectrograph, a birefringent wedge prism, and a segmented polarizer. Compared to the standard rotating-retarder fixed-analyzer spectro-polarimeter, only a single measurement is required and an up to 21-fold reduced acquisition time is shown. The measured Stokes parameters allow us to differentiate between vibrational symmetries and to determine the depolarization ratio ρ by data post-processing...
November 21, 2017: Journal of Chemical Physics
Razvigor Ossikovski, Oriol Arteaga, Sang Hyuk Yoo, Enric Garcia-Caurel, Kurt Hingerl
We demonstrate experimentally the validity of the partial spatial coherence formalism in Mueller polarimetry and show that, in a finite spatial resolution experiment, the measured response is obtained through convolving the theoretical one with the instrument function. The reported results are of primary importance for Mueller imaging systems.
November 15, 2017: Optics Letters
Ji Qi, Honghui He, Jianyu Lin, Yang Dong, Dongsheng Chen, Hui Ma, Daniel S Elson
Tissue depolarization and linear retardance are the main polarization characteristics of interest for bulk tissue characterization, and are normally interpreted from Mueller polarimetry. Stokes polarimetry can be conducted using simpler instrumentation and in a shorter time. Here we use Stokes polarimetric imaging with circularly polarized illumination to assess the circular depolarization and linear retardance properties of tissue. Results obtained were compared with Mueller polarimetry in transmission and reflection geometry respectively...
November 13, 2017: Journal of Biophotonics
B R Johnson, F Columbro, D Araujo, M Limon, B Smiley, G Jones, B Reichborn-Kjennerud, A Miller, S Gupta
In this paper, we present the design and measured performance of a novel cryogenic motor based on a superconducting magnetic bearing (SMB). The motor is tailored for use in millimeter-wave half-wave plate (HWP) polarimeters, where a HWP is rapidly rotated in front of a polarization analyzer or polarization-sensitive detector. This polarimetry technique is commonly used in cosmic microwave background polarization studies. The SMB we use is composed of fourteen yttrium barium copper oxide (YBCO) disks and a contiguous neodymium iron boron (NdFeB) ring magnet...
October 2017: Review of Scientific Instruments
Thomas Fromenteze, Okan Yurduseven, Michael Boyarsky, Jonah Gollub, Daniel L Marks, David R Smith
We propose a polarimetric microwave imaging technique that exploits recent advances in computational imaging. We utilize a frequency-diverse cavity-backed metasurface, allowing us to demonstrate high-resolution polarimetric imaging using a single transceiver and frequency sweep over the operational microwave bandwidth. The frequency-diverse metasurface imager greatly simplifies the system architecture compared with active arrays and other conventional microwave imaging approaches. We further develop the theoretical framework for computational polarimetric imaging and validate the approach experimentally using a multi-modal leaky cavity...
October 30, 2017: Optics Express
Yang Dong, Honghui He, Wei Sheng, Jian Wu, Hui Ma
Skin tissue consists of collagen and elastic fibres, which are highly susceptible to damage when exposed to ultraviolet radiation (UVR), leading to skin aging and cancer. However, a lack of non-invasive detection methods makes determining the degree of UVR damage to skin in real time difficult. As one of the fundamental features of light, polarization can be used to develop imaging techniques capable of providing structural information about tissues. In particular, Mueller matrix polarimetry is suitable for detecting changes in collagen and elastic fibres...
October 31, 2017: Scientific Reports
Alexa W Hudnut, Behzad Babaei, Sonya Liu, Brent K Larson, Shannon M Mumenthaler, Andrea M Armani
Characterizing the mechanical behavior of living tissue presents an interesting challenge because the elasticity varies by eight orders of magnitude, from 50Pa to 5GPa. In the present work, a non-destructive optical fiber photoelastic polarimetry system is used to analyze the mechanical properties of resected samples from porcine liver, kidney, and pancreas. Using a quasi-linear viscoelastic fit, the elastic modulus values of the different organ systems are determined. They are in agreement with previous work...
October 1, 2017: Biomedical Optics Express
Iftikhar Ahmad
Myocardial infarction (MI), a cause of significant morbidity and mortality, is typically followed by microstructural alterations where the necrotic myocardium is steadily replaced with a collagen scar. Engineered remodeling of the fibrotic scar via stem cell regeneration has been shown to improve/restore the myocardium function after MI. Nevertheless, the heterogeneous nature of the scar patch may impair the myocardial electrical integrity, leading to the formation of arrhythmogenesis. Radiofrequency ablation (RFA) offers an effective treatment for focal arrhythmias where local heating generated via electric current at specific spots in the myocardium ablate the arrhythmogenic foci...
October 2017: Journal of Biomedical Optics
Emilio Pedrotti, Christian Luigi Demasi, Enrico Bruni, Francesca Bosello, Paolo Plinio Di Sarro, Mattia Passilongo, Adriano Fasolo, Nicola Gennaro, Alessandra De Gregorio, Marcello Ferrari, Giorgio Marchini
OBJECTIVES: To assess the occurrence of glaucoma, eyelid, corneal and macular disorders in a cohort of patients with obstructive sleep apnoea (OSA) diagnosed by overnight polysomnography and to investigate into the risk factors for the above eye diseases (EDs). DESIGN: Cross-sectional cohort study between 2014 and 2015. SETTING: Unit of Respiratory Medicine and Eye Clinic of the University of Verona. PARTICIPANTS: 431 consecutive patients were considered eligible...
October 22, 2017: BMJ Open
Marta Pokrzywnicka, Robert Koncki
Disaccharides are determined mainly for dietetic purposes, hence the most analyses are carried out for food and drink samples. Its content can also be used to profile groceries in order to identify the origin and quality of the products. They also can be an indicator of the rate of metabolism as well as for the control of some technological and biotechnological processes. Unfortunately most of technological analysis are performed with nonselective polarimetry methods. Sugars due to specific physicochemical properties of compounds are difficult to determine with classical analytical techniques...
October 20, 2017: Critical Reviews in Analytical Chemistry
Tatiana Novikova
This paper provides an overview of the current research in the field of optical techniques for cervical neoplasia detection and covers a wide range of the existing and emerging technologies. Using colposcopy, a visual inspection of the uterine cervix with a colposcope (a binocular microscope with 3- to 15-fold magnification), has proven to be an efficient approach for the detection of invasive cancer. Nevertheless, the development of a reliable and cost-effective technique for the identification of precancerous lesions, confined to the epithelium (cervical intraepithelial neoplasia) still remains a challenging problem...
2017: Beilstein Journal of Nanotechnology
Aarón Cofré, Asticio Vargas, Fabián A Torres-Ruiz, Juan Campos, Angel Lizana, María M Sánchez-López, Ignacio Moreno
We report the realization of polarization sensitive split lens configurations. While split lenses can be used to easily generate different types of controlled structured light patterns, their realization has been limited so far to scalar beams. Here we propose and experimentally demonstrate their generalization to vectorial split lenses, leading to light patterns with customized intensity and state of polarization. We demonstrate how these polarization split lenses can be experimentally implemented by means of an optical system using two liquid crystal spatial light modulators, each one phase modulating one orthogonal polarization component...
October 2, 2017: Optics Express
Denis A Belyaev, Konstantin B Yushkov, Sergey P Anikin, Yuri S Dobrolenskiy, Aleksander Laskin, Sergey N Mantsevich, Vladimir Ya Molchanov, Sergey A Potanin, Oleg I Korablev
Spectral imaging in the near infrared is a promising method for mineralogy analysis, in particular well-suited for airless celestial objects or those with faint atmospheres. Additional information about structure and composition of minerals can be obtained using spectral polarimetry with high spatial resolution. We report design and performance of laboratory prototype for a compact near infrared acousto-optic imaging spectro-polarimeter, which may be implemented for remote or close-up analysis of planetary surfaces...
October 16, 2017: Optics Express
Mykola Shopa, Nazar Ftomyn, Yaroslav Shopa
A method of high-accuracy polarimetry, which includes optical activity measurements' systematic errors, was realized with a dual-wavelength polarimeter for the two wavelengths of 635 and 650 nm. Simultaneous measurements with neighboring wavelengths significantly improved the data processing by increasing the amount of obtained data to eliminate the systematic errors. For a langasite crystal, La3Ga5SiO14, we measured the temperature dependence of the gyration tensor component g11. Our acquired value does not exceed 0...
June 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Yu-Ming Wei, Ying Yu, Jing Wang, Lin Liu, Hai-Qiao Ni, Zhi-Chuan Niu, Jun-Tao Li, Xue-Hua Wang, Si-Yuan Yu
We investigate optical second harmonic generation (SHG) from individual self-catalyzed zinc-blende (ZB) GaAs nanowires (NWs), where the polarimetry strongly depends on the NW diameter. We report a direct observation on the SHG induced by surface nonlinear susceptibilities in a single, ultra-thin GaAs NW. By considering the contributions from both optical field and structural discontinuities in our theoretical model, we can well explain the optical SHG polarimetry from NWs with different diameters. We also show that the optical in-coupling coefficient arising from the depolarization electromagnetic field can determine the polarization of the SHG...
October 26, 2017: Nanoscale
Ji Qi, Honghui He, Hui Ma, Daniel S Elson
The polar decomposition method for Mueller matrices proposed by Lu-Chipman has been demonstrated and validated for many applications. However, in some situations, e.g., when analyzing the Mueller matrix of birefringent turbid media with Mie-sized scatterers acquired in reflection geometry, the method may suffer from limitations due to the assumptions required by this method. Here we extend the Lu-Chipman method and show that it can provide more reasonable results for these situations. The method has been validated experimentally with turbid phantoms...
October 15, 2017: Optics Letters
Andréa S G Figueiredo-Rinhel, Lamartine L de Melo, Leandro O Bortot, Everton O L Santos, Micássio F Andrade, Ana Elisa C S Azzolini, Luciana M Kabeya, Antonio Caliri, Jairo K Bastos, Yara Maria Lucisano-Valim
OBJECTIVES: To examine whether the hydroalcoholic extract from Baccharis dracunculifolia leaves (BdE) modulates the human neutrophil oxidative metabolism, degranulation, phagocytosis and microbial killing capacity. METHODS: In-vitro assays based on chemiluminescence, spectrophotometry, flow cytometry and polarimetry were used, as well as docking calculations. KEY FINDINGS: At concentrations that effectively suppressed the neutrophil oxidative metabolism elicited by soluble and particulate stimuli (<10 μg/ml), without clear signs of cytotoxicity, BdE (1) inhibited NADPH oxidase and myeloperoxidase activity; (2) scavenged H2 O2 and HOCl; (3) weakly inhibited phagocytosis; and (4) did not affect neutrophil degranulation and microbial killing capacity, the expression levels of TLR2, TLR4, FcγRIIa, FcγRIIIb and CR3 and the activity of elastase and lysozyme...
October 10, 2017: Journal of Pharmacy and Pharmacology
Dénes Száz, Alexandra Farkas, András Barta, Balázs Kretzer, Miklós Blahó, Ádám Egri, Gyula Szabó, Gábor Horváth
According to Thorkild Ramskou's theory proposed in 1967, under overcast and foggy skies, Viking seafarers might have used skylight polarization analysed with special crystals called sunstones to determine the position of the invisible Sun. After finding the occluded Sun with sunstones, its elevation angle had to be measured and its shadow had to be projected onto the horizontal surface of a sun compass. According to Ramskou's theory, these sunstones might have been birefringent calcite or dichroic cordierite or tourmaline crystals working as polarizers...
September 2017: Proceedings. Mathematical, Physical, and Engineering Sciences
Oriol Arteaga, Razvigor Ossikovski, Ertan Kuntman, Mehmet A Kuntman, Adolf Canillas, Enric Garcia-Caurel
In this Letter we describe an experiment in which coherent light is sent through a calcite crystal that separates the photons by their polarization. The two beams are then let to superpose, and this recombined beam is used to measure the Mueller matrix of the system. Results are interpreted according to our recent formalism of coherent superposition in material media. This is the first experimental implementation of a Young's experiment with complete polarimetry, and it is demonstrated that our method can be used for the experimental synthesis of optical devices with on-demand optical properties...
October 1, 2017: Optics Letters
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
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